Tag: surgery

Categories
Feature Articles

Meditate to Medicate: Mindfulness Meditation as a Complementary Therapy for Surgical Patients

Mind-body therapies such as mindfulness meditation (MM) are increasingly being studied and applied as legitimate medical therapies. Since becoming popular in the 1970s, MM has been shown to improve psychological states such as anxiety and depression. The scope of MM has expanded in recent years, and MM has been shown to have positive effects on pain, recovery time, and even wound healing after surgery. The number and types of surgery are increasing with the ageing population, and MM has potential as a non-surgical therapy to help hasten recovery, minimise analgesic consumption, and improve overall satisfaction after surgery. Training patients in MM before surgery may be implemented at low cost and up to 24 hours before admission. Given these benefits, complementary mind-body therapies such as MM have potential to improve a patient’s surgical experience and outcomes. Despite the potential benefits, MM is not currently used routinely for patients undergoing surgery. The literature shows that there is a perceived suspicion of the practice’s effectiveness, which appears to hamper its clinical acceptance. Critics cite concerns about patients’ perception of meditation given its religious connotations and whether they would be encouraged to accept MM as a valid therapy. This essay explores the application of MM as a complementary therapy to expedite recovery from surgical admission and concludes that meditation may be as effective as medication in some circumstances.

 

Introduction

“The part can never be well unless the whole is well.” This epithet offered by Plato 2300 years ago refers to the symbiotic relationship between mental and physical health, and has increasingly been embraced by Western society [1]. The concept that psychological state can influence physical well-being has contributed to the acceptance and use of mind-body therapies and motivated research into their health benefits. Recent scientific enquiry has noted diverse benefits of meditation such as reduced anxiety and depression levels, improved cardiac health, heightened immunity, and fewer post-chemotherapy adverse symptoms among cancer patients [2-4]. Researchers have also established a strong link between mind-body therapies and pain attenuation [5]. These findings suggest that these therapies may have potential as treatment for elective surgery inpatients.

With the increased number and types of surgical procedures required by an ageing population, meditation has been proposed as a means of improving post-operative outcomes, particularly after elective surgery [6]. Despite reported benefits and potentially low implementation costs [7], traditional medicine has been slow in adopting these alternatives. Critics remain sceptical of the efficacy and practicality of meditation, whereas advocates suggest that the analgesic qualities indicate clinical potential. To reconcile these opposing views, one must consider the logistical, psychosocial, and therapeutic aspects of meditation in the surgical context.

 

Mindfulness meditation

Meditation is often defined as mental exercises and techniques designed to calm the mind through physiological processes [8-10]. Mindfulness meditation (MM) sometimes referred to as ‘Vipassana practice’ or ‘insight meditation’, was thought to have been conceived by Buddhist scholars over 2000 years ago in India and is inextricably linked with Buddhist theology [11]. It involves cultivating a focused psychological attention to the internal and external experiences occurring in the present moment [12,13]. In practice, MM requires attentiveness to simple physical sensations such as breathing, eating, or sitting. Technical applications of this approach vary. One popular methodology in a clinical setting involves using one’s imagination to mentally scan the entire body for awareness of physical sensations without judgment, beginning with the head and progressing to the toes. This can be used for any duration and in many circumstances. MM may also incorporate ‘guided imagery’ techniques in a clinical context, in which the patient visualises his or her own healing process and affirms thoughts of positivity regarding the management of illness [14].

 

MM as a form of therapy

Despite its origins in antiquity, MM has recently been adopted by Western society [15], and today’s incarnation is mostly secular [16]. One of the first occasions of mindfulness being introduced to Western medicine occurred in 1979 by Kabat-Zinn’s Mindfulness Based Stress Reduction (MBSR) program at the Stress Reduction Clinic at the University of Massachusetts Medical Center [3,17]. The inaugural program described reduced self-reported scores for depression and anxiety in participants with psychological problems [11].

To implement MM as a therapeutic tool, Kabat-Zinn adapted the methodology. He anticipated that the introduction of an alternative medicine, particularly one with religious associations, would be denounced by orthodox medical practitioners as the work of charlatans or mystics [17]. Overcoming this prevailing medical stigma was integral to the wider acceptance of mindfulness today. Accordingly, Kabat-Zinn distinguished MBSR from its religious counterpart by exploring the curative potential of meditation and designed it to be used as a clinical tool that complemented rather than replaced conventional medical therapies.

The scope of clinical mindfulness has expanded greatly with wider acceptance of MM by the wider scientific community. Current programs include mindfulness-based cognitive therapy, acceptance and commitment therapy, and mindfulness-based relapse prevention [18,19]. There are now even smart phone applications, DVDs, and self-help books, which have propelled mindfulness concepts into the public domain.

The acceptance of mindfulness by the medical community is also evidenced by the recent interest in the scientific evaluation of mindfulness as a health promotion tool. For example, in the 2008-09 fiscal year, the US government funded hundreds of studies concerning the clinical applications of various meditative practices, at a cost of US $51 million [17].

 

MM and surgical outcomes

By influencing psychological states, MM may help address post-surgical complications such as pain and reduced functioning [20]. A systematic review of studies that evaluated psychological variables and surgical outcomes found that psychological state strongly correlates with early recovery, although differences in study design restrict the ability to confidently pool results [20]. Psychological factors have also been shown on occasion to be superior predictors of post-operative outcomes than the surgical intervention itself [14]. Despite continued technological innovation, today many patients endure moderate to severe negative post-operative outcomes [21]. For example, up to 40% of patients who undergo elective joint replacement surgery report suboptimal functional improvement, pain relief, and overall satisfaction after their procedure [22]. These issues suggest that there is a need for complementary therapies to support existing therapies in a surgical setting.

Mind-body therapies such as MM are being increasingly evaluated for their effects on post-operative psychological variables. The use of mind-body therapies as a nonpharmacological adjunct has been well studied in cardiac, abdominal, and orthopaedic surgeries [14]. In these contexts, MM is associated with improved levels of pain, anxiety, fatigue, and distress [14]. Reduced systolic blood pressure has been reported during the post-operative period in patients who have practised a guided-imagery protocol [23]. Other benefits include shorter hospital stay and promotion of wound healing in some studies [14,24].

MM has been shown to be useful for reducing reliance on analgesia in the post-operative period and beyond [14]. Analgesia consumption levels can be used as a proxy for pain control. Although analgesic use is essential for promoting surgical recovery, too great a reliance on pharmaceuticals increases the risk of adverse side effects such as nausea, respiratory depression, and lethargy [25]. Some analgesics can also predispose to long-term dependency if their use is not appropriately stewarded. Palmaro et al. [26] observed that one-third of patients undergoing orthopaedic surgery for carpal tunnel syndrome had persistent and increased consumption of anti-neuropathic and/or opioid analgesics for more than two months after surgery. Among this population, psychiatric disorders and subjective levels of pre-operative pain explained this increased use [26]. MM may positively affect these two variables and reduce medication use. An estimated 234.2 million surgeries are performed worldwide each year, many of these necessitating pain medications [27]. It would therefore make fiscal sense to reduce the amount of pharmaceuticals required after surgery through the use of nonpharmacological therapies such as MM.

 

Proposed mechanisms to explain the effects of MM on post-operative pain

Meditative practice has been shown to change brain structure and function [28]. These effects may be seen both immediately and from chronic practice as demonstrated via brain imaging modalities such as fMRI, SPECT and PET [28]. Firstly, the prefrontal cortex (PFC) is intensely active during meditation, specifically the lateral prefrontal regions [28,29]. The ventromedial areas of the PFC are responsible for the affective integration of sensory input, whilst the posterolateral regions are concerned with sensory appraisal without self-referential value [29]. It is proposed that a neuronal shift away from the ventromedial prefrontal regions to the posterolateral centres supports a more self-detached analysis of interoceptive and exteroceptive sensory events [29]. Secondly, additional neural correlates such as modulation of the limbic system contribute to meditative effects [28]. MM practice has been shown to reduce the activity of the amygdala, and broader limbic structures concerned with emotional reactions [28].  For example, after eight weeks of an MM intervention, arterial spin labelling functional MRI showed neuroarchitectural changes such as increasing grey matter concentration within the left hippocampus an amygdala [16]. These regions are associated with emotional regulation, which may account for reduced anxiety and improved coping reported after programs of a similar duration [30]. In addition to this, MM has been posited to exert influence on the hypothalamus, which by extension shifts autonomic nervous system function towards increased parasympathetic activity [28]. This hypothesis attempts to explain physiological reductions in heart rates, blood pressure and serum cortisol levels which all evidence relaxation experienced during MM [28].

Another potential benefit of MM as a surgical therapy is pain modulation. However the exact mechanisms through which MM regulates pain are unknown [3,31]. Zeidan et al. [5] suggested MM can attenuate post-operative pain, reporting a 40% reduction in pain intensity and 57% reduction in pain unpleasantness following mindfulness intervention in a laboratory setting. The authors posited that this phenomenon results from synergistic interactions of improved attentional control, expectation modulation, and a placebo effect. By exerting attentional control on physical sensations other than discomfort, MM is thought to dampen the saliency of nociceptive stimuli.

Although this explanation seems to be reductive at face value, it is consistent with knowledge about complex neurobiology. The influence of MM on neurological pain-modulating networks is only now being explored. The cognitive inhibition of pain has traditionally been attributed to opioidergic mechanisms [32,33]. This model proposes that endogenous opioids are secreted by regions of the brain with an abundance of opioid receptors [33] and that these natural opioids elicit analgesic effects. Opioid receptors are found in high concentrations in the anterior cingulate cortex, orbitofrontal cortex (OFC), and insula [34]. Pain relief attributed to a placebo effect, conditioned pain modulation, and attentional control mechanisms such as those involved in MM rely on opioidergic pain relief [35-37]. These analgesic effects can be reversed after administration with opioid antagonists such as naloxone [34]. Imaging studies have shown that MM-induced analgesia is associated with increased activation in these regions of the brain [34]. This suggests that opioidergic mechanisms may account for some of the analgesic effects associated with MM.

Pain attenuation by MM may be supplemented by non-opioidergic mechanisms because opioidergic and non-opioidergic brain regions work synergistically. In MM, the OFC projects synapses to the thalamic reticular nuclei (TRN) which, via further projections exerts inhibitory control over the thalamus, an area considered to be the ‘gatekeeper’ through which all sensory information must pass [38]. When the TRN is active (either through the OFC or distinct mechanisms) ascending information such as nociception may be filtered from triggering conscious awareness [38]. MM therapy responses might therefore be mediated by the interaction between the OFC and the TRN, which appears to inhibit nociception from reaching the conscious part of the brain, the cerebral cortex. Self-facilitated pain modulatory systems seem to be engaged by non-evaluative recognition of an unpleasant physical sensation such as nociception [38]. Pain reduction experienced during MM is also associated with thalamic deactivation, which suggests a pain-gating effect may be exerted by the limbic system [5]. This suggests that nociception is influenced by the complex interaction of expectations, emotions, and cognitive appraisals, and may be modulated by the meta-cognitive task of focusing on the present moment [5].

 

Delivery of MM therapy to elective surgical patients

MM-based interventions vary in format and administration. Group mindfulness interventions are often preferable in clinical and research settings, and have been shown to expedite improved socialisation, program participation, and skill acquisition [14].

Group therapy with a set number of sessions of prescribed length may be more cost-effective than individual one-to-one interventions [14]. In group formats, a health professional such as a psychologist, physician or nurse instructs participants and distributes supporting material such as books and audiotapes to reinforce the program rationale and encourage independent practice outside standardised sessions.

It may not be practical to offer group sessions for patients undergoing elective surgery because of the nature of elective admissions, which are typically non-emergency procedures and can be delayed or rescheduled at short notice. Patients requiring more urgent surgery would not have sufficient advance notice to begin preoperative group therapy. Therefore, viable program methodologies should be flexible in terms of participant admission or delivered on an individualised basis as part of pre-operative patient care.

Personalised instruction or a single session with a psychologist can be tailored to the patient’s level of comprehension. Patients could also be given the opportunity for follow-up sessions to consolidate skills learned before admission.

Regardless of the mode of delivery, the rationale, advantages, and disadvantages of MM should be explained to the patient before surgery. The patient’s cognitive capacity and psychological state should be assessed by the physician or psychologist to evaluate his or her suitability for MM intervention and provide baseline psychological scores for comparison.

The benefits of regular MM practice in clinical practice have been well documented, and these skills can be consolidated for life [17]. In the context of pre-operative MM programs, optimum duration and timing of MM programs should be considered. The MBSR program developed by Kabat-Zinn [13] spans an 8-week course involving a 20-minute intervention each day. Many clinical programs use a similar program design, which has shown to be adequate to elicit desired benefits [17].

However it does not seem to be necessary for pre-operative programs to be as long as eight weeks to elicit desired effects. MM therapy given for the first time 24 hours before an operation has been shown to be beneficial. For example, Manyande et al. [39] reported reduced scores for post-operative pain and distress, and ward analgesic consumption for surgical patients given a 15-minute audio recording 1 day before elective abdominal surgery. Other studies have reported similar results [18,34,40]. Thus, although the benefits of MM are generally associated with regular practice (which may discourage some from taking up the practice), these findings imply that MM therapy involving short mental training may produce benefits even when undertaken in the days before surgery.

 

Limitations to MM therapy in the surgical context

There are potential limitations to MM as a pre- and post-operative therapy for surgical patients. The success of MM programs can be limited by surgery type and patient attributes, such as physical or cognitive impairment [14]. The stress associated with a hospital admission and surgery may impair a patient’s ability to learn a new skill such as MM [41].

Implementation of standardised programs across healthcare providers may require additional funding, development of standardised educational material, and targeted training for healthcare professionals. Estimates of the resources needed would also vary according to differences between practices and institutional infrastructure. However, the cost of implementing MM programs may be recovered at least in part by improved recovery, reduced length of stay, reduced complication rates and reduced analgesic consumption [14,24,39,42]. Further cost-benefit analysis of MM programs for surgical patients may be warranted to better understand the organisational fiscal advantages associated with the use of MM therapies.

The effect size of MM intervention on post-operative outcomes has been subject to debate. Some studies investigating the use of pre-operative mind-body therapies in the surgical context failed to establish changes to post-operative outcomes such as pain and duration of hospital stay [14]. For example, Scott and Clum [43] observed no significant effects of treatments on outcome measures such pain, anxiety and analgesic intake after an attentional control regimen initiated 24hr prior to abdominal surgery. Other studies described mixed outcomes of such protocols [14,39]. It has been suggested that heterogeneity in study design and differences in the surgical context in which they are examined restrict generalizations being formed into the effectiveness of individual protocol design [14]. This is additionally hampered by fluid definitions of ‘mind-body therapies’ and noted methodological flaws consistent throughout much of existing literature, such as reduced sample size, inadequate controls and insufficient study duration [14,17]. Additionally, it is difficult to account for the influence of external factors on broader research outcomes. Factors such as insurance coverage may exert control on measures such as duration of hospital stay which may distort findings [14]. Further research may need to be conducted to reconcile these considerations and establish the clinical scope of MM.

It is unknown how receptive patients would be to learning MM around the time of surgery. Patients may be sceptical of or uninformed about mind-body therapies [17]. It is also unclear if the religious connotations associated with MM would promote or hinder patient participation [17]. Some patients may be discouraged by anything resembling a religious practice or indeed the opposite may be true [17]. Such phenomena may be subject to many individual patient factors and could be difficult to predict in the absence of empirical data. Future enquiry may seek to better understand the influence of individual patient preferences and values on MM adherence. It may be reasoned that patient education and evidence-based practice could also help dispel misconceptions about MM therapy and foster its adoption amongst the wider community, but research would be needed to corroborate this.

 

Conclusion

Since its adoption by Western society, MM has become increasingly used as a clinical tool. With an ageing population and increased demand for surgical interventions, complementary therapies such as MM should be considered. In the surgical setting, MM may reduce pain, anxiety, and distress, improve contentment, psychological state, and recovery time, and could decrease the need for high levels of medication and the risks associated with polypharmacy. Beyond its physiological effects, MM may also benefit those seeking relief from mental and physical stresses encountered during their hospital admission. Further research and development are needed to establish viable standardised treatment programs. Despite the mixed opinions about MM, it is likely that future medical practitioners will regard MM as a powerful therapeutic option in addition to its pharmacological counterpart.

 

Conflict of interest

None.

 

Acknowledgements

The authors wish to acknowledge Laurel Mackinnon, PhD, ELS, and Sharon Johnatty, PhD, for their invaluable assistance in editing this article.

 

References

[1] Wright J. Psychosomatic Interactions. Int J Adv Couns. 1986;9(1):47-60.

[2] Davidson RJ, Kabat-Zinn J, Schumacher J, Rosenkranz M, Muller D, Santorelli SF et al. Alterations in brain and immune function produced by mindfulness meditation. Psychosom Med. 2003; 65(4):564-70.

[3] Ditto B, Eclache M, Goldman N. Short-term autonomic and cardiovascular effects of mindfulness body scan meditation. Ann Behav Med. 2006;32(3):227-34.

[4] Henderson VP, Clemow L, Massion AO, Hurley T, Druker S, Hébert J. The effects of mindfulness-based stress reduction on psychosocial outcomes and quality of life in early-stage breast cancer patients: a randomized trial. Breast Cancer Res Treat. 2012;131(1):99-109. [5] Zeidan F, Martucci KT, Kraft RA, Gordon NS, Mchaffie JG, Coghill RC. Brain mechanisms supporting the modulation of pain by mindfulness meditation. J Neurosci. 2011;31(14):5540-8.

[6] Bettelli G. Anaesthesia for the elderly outpatient: preoperative assessment and evaluation, anaesthetic technique and postoperative pain management. Curr Opin Anaesthesiol. 2010;23(6):726-31.

[7] Miller JJ, Fletcher K, Kabat-Zinn J. Three-year follow-up and clinical implications of a mindfulness meditation-based stress reduction intervention in the treatment of anxiety disorders. Gen Hosp Psychiat. 1995;17(3),192-200.

[8] May A, Gaser C. Magnetic resonance-based morphometry: a window into structural plasticity of the brain. Curr Opin Neurol. 2006;19:407-11.

[9] Grant JA. Meditative analgesia: The current state of the field. Ann N Y Acad Sci. 2014;1307(1):55-63.

[10] Lutz A, Slagter HA, Dunne JD, Davidson RJ. Attention regulation and monitoring in meditation. Trends Cogn Sci. 2008;12(4):163-9.

[11] Bauer-Wu S. Mindfulness meditation. Oncology. 2010;24(10):36-40.

[12] Baer RA. Mindfulness training as a clinical intervention: a conceptual and empirical review. Clin Psychol Sci Pract. 2003;10(2):125-43.

[13] Kabat-Zinn, J. An outpatient program in behavioral medicine for chronic pain patients based on the practice of mindfulness meditation: theoretical considerations and preliminary results. Gen Hosp Psychistry. 1982;4:33-47.

[14] Nelson EA, Dowsey MM, Knowles SR, Castle DJ, Salzberg MR, Monshat K et al. Systematic review of the efficacy of pre-surgical mind-body based therapies on post-operative outcome measures. Complement Ther Med. 2013;21(6):697-711.

[15] Grossman P, Nieman,L, Schmidt S, Walach H. Mindfulness-based stress reduction and health benefits. A meta-analysis. Psychosom Res. 2004;57:35-43.

[16] Kristeller JL. Mindfulness meditation. In: P. Lehrer, R.L. Woolfolk, & W.E. Simes. Principles and Practice of Stress Management. 2nd Edition. New York: Guildford Press. 2007;393-427.

[17] Hickey WS. Meditation as medicine: a critique. Cross Curr. 2010;60(2):168-84.

[18] Segal Z, Williams M, Teasdale J. Mindfulness-based cognitive therapy for depression: A new approach to preventing relapse: Book review. Cogn Behav Ther. 2002;31:193-4.

[19] Bowen S, Chawla N, Collins SE, Witkiewitz K, Hsu S, Grow J et al. Mindfulness-based relapse prevention for substance use disorders: a pilot efficacy trial. Subst Abus. 2009;30:295-305.

[20] Mavros MN, Athanasiou S, Gkegkes ID, Polyzos KA, Peppas G, Falagas ME et al. Do psychological variables affect early surgical recovery? PLoS ONE. 2011;6(5):e20306.

[21] Pyati S, Gan TJ. Perioperative pain management. CNS Drugs. 2007;21(3):185-211.

[22] Hawker GA, Badley EM, Croxford R, Coyte PH, Glazier RJ, Guan JI et al. A population-based nested case-control study of the costs of hip and knee replacement surgery. Med Care. 2009;47(7):732-41.

[23] Lin PC. An evaluation of the effectiveness of relaxation therapy for patients receiving joint-replacement surgery. J Clin Nurs. 2012;21(5-6):601-8.

[24] Broadbent E, Kahokehr A, Booth RJ, Thomas J, Windsor JA, Buchanan CM et al. A brief relaxation intervention reduces stress and improves surgical wound healing response: A randomised trial. Brain Behav Immun. 2012;26(2):212-7.

[25] Spiller R, Aziz Q, Creed F, Emmanuel A, Houghton L, Hungin P et al. Guidelines on the irritable bowel syndrome: mechanisms and practical management. Gut. 2007;56(12):1770-98.

[26] Palmaro A, Fuzier R, Serres I, Bourrel R, Lapeyre-Mestre M. Analgesic drug consumption increases after carpal tunnel surgery: a pharmacoepidemiological study investigating postoperative pain. Clin Ther. 2015;37(8):e64-5.

[27] Weiser TG, Regenbogen SE, Thompson KD, Haynes AB, Lipsitz SR, Berry WR et al. An estimation of the global volume of surgery: a modelling strategy based on available data. Lancet. 2008;372(9633):139-44.

[28] Wasi P. Brain and meditation. J Neurol Sci. 2009;285(1):s36.

[29] Farb NA, Segal ZV, Mayberg H, Bean J, McKeon D, Fatima Z et al. Attending to the present: mindfulness meditation reveals distinct neural modes of self-reference. Soc Cogn Affect Neur. 2007;2(4):313-322.

[30] Hoge EA, Metcalf CA, Morris LK, Simon NM. Mindfulness meditation for generalized anxiety disorder: effects on resilience, anxiety, and hypothalamic pituitary adrenal (HPA) axis. ‎Psychosom Med. 2013;75(3):A-2.

[31] Kahokehr A, Broadbent E, Wheeler BRL, Sammour T, Hill AG. The effect of perioperative psychological intervention on fatigue after laparoscopic cholecystectomy: a randomized controlled trial. Surg Endosc. 2012;26(6):1730-6.

[32] Wager TD, Scott DJ, Zubiet, J-K. Placebo effects on human mu-opioid activity during pain. Proc Natl Acad Sci USA. 2007;104(26):11056-61.

[33] Tracey I, Ploghaus A, Gati JS, Smith S, Matthews PM, Gati JS et al. Imaging attentional modulation of pain in the periaqueductal gray in humans. J Neurosci. 2002;22(7);2748-52.

[34] Zeidan, F, Adler-Neal AL, Wells RE, Stagnaro E, May LM, Eisenach JC et al. Mindfulness-meditation-based pain relief is not mediated by endogenous opioids. J Neurosci. 2016;36(11):3391-7.

[35] Sprenger C, Eippert F, Finsterbusch J, Bingel U, Rose M, Büchel C. Attention modulates spinal cord responses to pain. Curr Biol. 2012; 22(11):1019-22.

[36] Eippert F, Bingel U, Schoell ED, Yacubian J, Klinger R, Lorenz J et al. Activation of the opioidergic descending pain control system underlies placebo analgesia. Neuron. 2009;63(4):533-43.

[37] King CD, Goodin B, Kindler LL, Caudle R, Edwards R, Gravenstein N et al. Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing. J Behav Med. 2013;36(3):315-27.

[38] Zikopoulos B, Barbas H. Circuits for multisensory integration and attentional modulation through the prefrontal cortex and the thalamic reticular nucleus in primates. Rev Neurosci. 2007;18(6):417-38.

[39] Manyande A, Berg S, Gettins D, Stanford SC, Mazhero S, Marks DF et al. Preoperative rehearsal of active coping imagery influences subjective and hormonal responses to abdominal surgery. Psychosom Med. 1995;57(2):177-82.

[40] Lin P-C. An evaluation of the effectiveness of relaxation therapy for patients receiving joint replacement surgery. J Clin Nurs. 2012;21(5-6):601-8.

[41] Jawaid M, Mushtaq A, Mukhtar S, Khan Z. Preoperative anxiety before elective surgery. Neurosciences. 2007;12(2):145-8.

[42] Manyande A, Salmon P. Effects of pre-operative relaxation on post-operative analgesia: immediate increase and delayed reduction. Br J Health Psychol. 1998;3(Pt 3):215-24.

[43] Scott LE, Clum GA. Examining the interaction effects of coping style and brief interventions in the treatment of postsurgical pain. Pain 1984;20(3):279-91.

Categories
Guest Articles

Surgery: art or science?

Professor Ian Harris AM

It’s often said that surgery is more art than science. Rubbish. Too much emphasis is placed on surgeons’ technical skills and not enough on the decisions behind them.

Any good surgeon can operate, better surgeons know when to operate and the best surgeons know when not to. Knowing when to operate and when to hold off relies on weighing up relative probabilities of success and failure between alternatives.

Good decision makers (and therefore good surgeons) base such decisions on quality evidence, and this is where science comes in. The evidence we seek is evidence of the true effectiveness of an intervention, and it is the scientific method that provides us with the most accurate and reliable estimate of the truth. Faced with alternatives, surgeons can sometimes make the wrong choice by being unscientific.

Surgeons often decide to do certain procedures because it’s what’s usually done, because it’s what they were taught, because it sounds logical, or because it fits with their own observations. If the surgeon’s perception of effectiveness and the evidence from scientific studies align, there is little problem. It’s when the two conflict that there’s a problem: either the surgeon’s opinion or the evidence is wrong. Worse, sometimes there is no good quality evidence and we are left with the surgeon’s opinion.

There is abundant evidence that surgeons overestimate the effectiveness of surgery, and considerable evidence of seemingly effective operations (based on observational evidence) turning out to be ineffective on proper scientific testing.

So what evidence should we rely on? Put simply, when you are trying to determine true effectiveness, the best method is the one that is least wrong, i.e., the method that has the least error. The scientific method is constructed to reduce error – we rarely know the truth, but we can increase the likelihood of our estimates containing the truth and we can make those estimates more precise by reducing error. In other words, we can never be certain but we can reduce uncertainty.

There are two types of error: random error and systematic error. Random error is easy to understand. If you toss a coin ten times, you may get seven heads, but that doesn’t mean the coin is unbalanced. Toss it 100 times and if you get 100 heads then you have reduced random error (the play of chance in generating such a result) and it is now very likely (and we are more certain) that the coin is unbalanced.

Systematic error (bias) is when we consistently get the wrong answer because we are doing the experiment wrong. There are many causes of bias in science and many go unrecognised, like confirmation bias, selective outcome reporting bias, selective analysis bias, measurement bias, and confounding. Systematic error is poorly understood and a major reason for the difference between the true and the apparent effectiveness of many surgical procedures.

The best way to test the effectiveness of surgery and overcome bias (particularly when the outcome is subjective, such as with pain) is to compare it with a sham or placebo procedure and to keep the patients and those who measure the effectiveness ‘blinded’ to which treatment was given. Yet such studies, common in the drug world, are rare in surgery.

In a study that summarised the research that has compared surgery to sham or placebo procedures, it was shown that the surgery in most such studies was no better than pretending to do the procedure [1]. And in the studies where surgery was better than placebo, the difference was generally small.

It’s not always necessary to compare surgery to a sham – sometimes comparing it to non-surgical treatment is sufficient. This is particularly the case for objective outcomes (survival, recurrence of disease, anatomic corrections) where blinding is less important. But you still have to compare it to something – to merely report the results of an operation with no comparator provides no reference for effectiveness beyond some historical control (of different patients, with possibly different conditions, from another place and another time). Journals are littered with case reports showing that most people got better after receiving treatment X but such reports tell us nothing about what would have happened to the patients if they did not receive treatment X, or received some other treatment. These types of non-comparative studies continue to sustain many quack therapies as well as common medical and surgical therapies, just as they sustained the apparent effectiveness of bloodletting for thousands of years.

However, even when comparative studies are done, they are not always acted upon. In a study looking at the evidence base for orthopaedic surgical procedures, it was found that only about half of all orthopaedic procedures had been subjected to tests comparing them to not operating [2]. And for those procedures that had been compared to not operating, about half were shown to be no better than not operating, yet the operations were still being done. The other surgical specialties are unlikely to be much better.

So there are two problems in surgery: an evidence gap in which there’s a lack of high quality evidence to support current practice, and an evidence-practice gap where there’s high quality evidence that a procedure doesn’t work, yet it’s still performed.

Part of the problem is that operations are often introduced before there’s good quality evidence of their effectiveness in the real world. The studies comparing them to non-operative treatment or placebo often come much later – if at all.

Surgical procedures should not be introduced or funded until there’s high quality evidence showing their effectiveness, and it should be unethical to introduce a new technique without studying its effectiveness. Instead, the opposite is argued: that high quality comparative studies (placebo controlled trials) are unethical.

Often, procedures that surgeons consider to be obviously effective are later shown to be ineffective. In the US in the 1980s, a new procedure that removed some lung tissue was touted for emphysema. Animal studies and (non-comparative) results on humans were encouraging. So the procedure became commonplace. A comparative trial was called for but proponents argued that this would deprive many people of the benefits of the procedure, the effectiveness of which was obvious.

Medicare in the US decided only to fund the surgery if patients participated in a trial comparing it to non-surgical treatment. The trial was done and the surgery was found wanting. This cost Medicare some money, but much less than paying for the procedure for decades until someone else studied it. This type of solution should be considered in Australia – only introduce new procedures if they are being evaluated as part of a trial.

The current practice of surgery is not based on quality science. If you got a physicist from NASA to look at the quality of science supporting current surgical practice they would faint. But it is getting better. It is getting better because of advancements in our understanding, because of the spread of evidence based medicine (in teaching and in journal requirements, for example), and because surgeons are understanding science better. The trials are getting better, but the incorporation of the results of those trials into practice is slow and often meets resistance because of suspicions that stem from a lack of understanding of science and the biases that drive current practice.

Billions are spent worldwide on surgical procedures that may not be effective because in many areas of surgery we still rely on surgical opinions based on biased observations and tradition. It is time for surgery to be a real science and to rely on the kind of evidence on which other scientific endeavours rely; the kind of evidence that we demand of other medical specialties and of non-medical practitioners. It’s not too hard. It’s not unethical. It’s right, and it’s time.

 

References

[1] Wartolowska K, Judge A, Hopewell S, Collins GS, Dean BJF, Rombach I, et al. Use of placebo controls in the evaluation of surgery: systematic review. BMJ. 2014;348:3253.

[2] Lim HC, Adie S, Naylor JM, Harris IA. Randomised trial support for orthopaedic surgical procedures. PLoS One. 2014;9(6):96745.

Categories
Case Reports

Impact of socioeconomic status on the provision of surgical care

In Australia, there is an association between low socioeconomic status (SES) and poor health outcomes. Surgical conditions account for a large portion of a population’s disease burden. The aim was to determine the difference in provision of surgical care and patient satisfaction between low and high SES communities in Sydney, Australia. A cross sectional analytical study was conducted using questionnaire-based data. Patients were recruited from five general practice centres across low and high SES areas. Participants were eligible for this study if they had surgery performed under general anaesthesia  within  the  last  five years.  Analysis  was performed to determine whether waiting times for surgery and surgical consultations were different between low and high SES groups, and whether private health insurance impacted on waiting times. A total of 107 patient responses were used in the final data analysis. Waiting times for elective surgery were longer in the low SES group (p=0.002).The high SES group were more likely to have private health insurance (p <0.001) and were 28.6 times more likely to have their surgery in a private hospital. Private health insurance reduced waiting times for elective surgical procedures (p = 0.004), however, there was no difference in waiting times for initial surgical consults (p=0.449). Subjective patient satisfaction was similar between the two groups. In conclusion, our study demonstrates that SES does not impact on access to a surgical consultation, but a low SES is associated with longer waiting times for elective surgeries. Despite this, patients in both groups remained generally satisfied with their surgical care.

v6_i1_a18a

Introduction

In Australia, low socioeconomic status (SES) has been linked to poor health outcomes [1] with a 1.3 times greater mortality risk in low SES areas when compared to the highest SES areas. [2-3] Individuals living in more disadvantaged areas are more likely to engage in unhealthy behaviours, and their poorer health is reflected in more frequent utilisation of health care services. [4] Greater Western Sydney represents one of the lowest SES areas in Sydney, Australia [5] and according to the Socio-Economic Indexes of Areas (SEIFA), contains eight of the ten most disadvantaged areas in Sydney. [5-6] For general elective procedures, average waiting times in Greater Western Sydney hospitals varied from 23 to 93 days, compared with 4 to 36 days in other areas of Sydney. [6] Thus, timely and easily accessible provision of surgical services is a growing necessity for the expanding population of Greater Western Sydney.

Methods

The research was approved by the University of Western Sydney Human Research Ethics Committee (H9067).  The SEIFA [7] score was used to determine the areas chosen for data collection. A total of five Sydney General Practices, three located in low SES areas and two in high SES areas, were chosen randomly for patient recruitment.

The data collection tool employed was a survey which included questions relating to SES factors, health fund status, comorbidities, details of the surgical procedures undertaken, waiting times for operations,  follow-up   consultations,  post-operative   complications and patient satisfaction. The survey and written consent were offered to all General Practice waiting room patients over a period of two weeks by the authors. Patients were eligible to participate if they had undergone a surgical procedure in Sydney, performed under general anaesthesia within the last five years. The survey was anonymous with no personally identifying information recorded.

Data were analysed using Microsoft Excel 2010 and SPSS software version 22.0. Logarithmic values were calculated for all data sets and t-tests performed for analysis. Chi-squared analyses were conducted to assess the effect of private health insurance on hospital choice.

Results

A total of 107 surveys were eligible for analysis after excluding dental procedures, colonoscopies, procedures performed outside Sydney, emergency procedures, caesarean sections and respondents under 18 years of age.

Table 1 illustrates the characteristics of the sample studied. Notable differences between responses from high and low SES areas include level of education and private health insurance status. The median ages were 56 for low SES and 66 for high SES (p=0.02). Table 2 displays the types of surgical procedures that were included in the study.

v6_i1_a18b

v6_i1_a18c

Waiting times

The average waiting time for consultation with a surgeon was 2.5 weeks in the low SES group and two weeks in the high SES group (p=0.449). Private health insurance status did not influence this waiting time. Waiting times for elective surgery were on average six weeks in the low SES group and 2.5 weeks in the high SES group (p=0.002). Possession of private health insurance was associated with a decreased waiting time (p=0.004).

Private health insurance and choice of hospital

Responders with private health insurance were 28.6 times (p < 0.001) more likely to have surgery performed at a private hospital.

Patient satisfaction

Table 3 demonstrates rates of patient satisfaction between the low and high SES groups. There was an overall trend for patients in the lower SES groups to be dissatisfied with waiting times but be generally satisfied with other aspects of surgery.

v6_i1_a18d

Discussion

The study found that patients from lower SES groups had less private health insurance and longer wait times for surgery. Despite this, a high level of satisfaction was expressed across both SES groups regarding surgical outcomes and overall medical care during hospital admission.

These findings were anticipated and are consistent with previous research which has shown that patients in the public system experienced longer waiting times and were 60-95% less likely to undergo surgery than private patients. Furthermore, privately insured patients were also found to have greater access to surgical care, shorter overall length of stay and lower mortality rates. [8] This relationship creates the premise that increasing access to private care will relieve the burden on the public system and reduce waiting times. However, the converse has been shown to be the case, with an increase in waiting times for surgery when access to private hospitals is increased. [9] The trend for generally high levels of satisfaction is counter-intuitive, however, is consistent with the literature. [10-11]

The implications of longer waiting times in Western Sydney is of concern because the region’s population is expected to grow by 50% over the next 20 years, a growth of 1 million people [12], and the availability of health care services will have to expand to accommodate this increasing population. There are increasing numbers of additions to public hospital elective surgery waiting lists every year. [13] Availability and staffing of beds in public hospitals are lower in the Western Sydney region, and there is a relative lack of private hospitals compared to the wider Sydney metropolitan area [6]. Compounding the issue of access

to healthcare are lower rates of private health insurance membership and the generally poorer health of low SES populations. [6] It becomes apparent  that  there  is  a  relative  lack  of  services  available  in  low SES areas of Sydney. It is estimated that the cost of funding enough public hospital beds to accommodate a populace of this size would be a minimum of $1.29 billion a year. This poses the risk of escalating inequality in access to health services between the low SES areas of Western Sydney and the wider metropolitan area. [6] The NSW government has invested $1.3 billion from the recent health budget to upgrade existing hospitals [14], however, ongoing funding of these hospitals will need to increase to accommodate the growing demand. [6]

Data were collected from a small number of locations across only three SES regions in Sydney, providing a limited sample size for analysis. Recall bias would also have an impact on accuracy of responses, despite the criteria for a five year cut off. Future research would benefit from increasing data collection across a larger number of SES sites to reduce any possible sample bias. Furthermore, expanding data sources to include hospital databases would minimise recall bias, allowing for more objective and accurate data regarding the length of time spent on surgical waiting lists and utilisation of private health cover.

Conclusion

It is well established that a low SES is associated with poorer health. This study has found that patients from low SES areas experienced longer waiting times for elective surgery. A contributing factor to the longer waiting times was possession of private health insurance. Patients from low SES areas felt that they waited too long for their surgery; however, overall satisfaction ratings were generally high across both SES groups. The interplay between SES and the public and private health systems has created a disparity in access to timely elective surgery.

Acknowledgements

None.

Conflict of interest

None declared.

Correspondence

Z El-Hamawi: z.elhamawi@hotmail.com

References

[1] Armstrong BK, Gillespie JA, Leeder SR, Rubin GL, Russell LM. Challenges in health and health care for Australia. Med J Aust. 2007;187(9):485-489.

[2] Korda RJ, Clements MS, Kelman CW. Universal health care no guarantee of equity: Comparison of socioeconomic inequalities in the receipt of coronary procedures in patients with acute myocardial infarction and angina. BMC Public Health. 2009 14;9:460.

[3] Clarke P, Leigh A. Death, dollars and degrees: Socio-economic status and longevity in Australia. Economic Papers: 2011 Sept 3;30(No. 3): 348–355.

[4] Australian Bureau of Statistics. Health Status: Health & socioeconomic disadvantage of area. Canberra. 2006 May. Cat. No 4102.0

[5] Australian Bureau of Statistics. ABS releases measures of socio-economic advantage and disadvantage. Canberra. 2008 March.Cat. No. 2033.0.55.001

[6] Critical Condition: A comparative study of health services in Western Sydney [Internet]; Australia: Western Sydney Regional Organisation of Councils. August 2012. [cited 2013 Feb]

[7] Australian Bureau of Statistics. Census of population and housing: Socio-economic index for areas, Australia, 2011. Canberra. 2013 March. Cat. No. 2033.0.55.001

[8] Brameld K, Holman D, Moorin R. Possession of health insurance in Australia – how does it affect hospital use and outcomes? J Health Serv Res Policy. 2006;11(2):94-100.

[9] Duckett S.J. Private care and public waiting. Aust Health Rev. 2005;29(1);87-93

[10] Myles PS, Williams DL, Hendrata M, Anderson H, Weeks AM. Patient satisfaction after anaesthesia & surgery: Results of a prospective survey of 10811 patients. Br J Anaesth. 2000;84(1):6-10

[11] Mira JJ, Tomás O, Virtudes-Pérez M, Nebot C, Rodríguez-Marín J. Predictors of patient satisfaction in surgery. Surgery. 2009;145(5):536-541.

[12] New South Wales in the future: Preliminary 2013 population projections [Internet]. Australia: NSW Government Department of Planning and Infrastructure;2013 [cited 2014 Sept]

[13]  Australian  Institute of Health and Welfare. Australian hospital statistics 2011-12: Elective surgery waiting times – Summary. 2012 Oct

[14] $1.3 billion building boom for NSW hospitals [Internet].Media Release. Australia: NSW Government Budget 2014-2015; 2014. [cited 2014 Sept]

Categories
Review Articles

Bispectral analysis for intra-operative monitoring of the neurologically impaired: a literature review

Introduction: The bispectral index (BIS) is a technology which uses a modified electroencephalogram (EEG) to predict the likelihood that an anaesthetised patient has awareness of their surroundings. This method of monitoring was developed by analysing the EEGs of approximately 1000 patients with normal neurological function. It therefore has questionable applicability to those with neurological disability which may cause abnormal EEG patterns. Aim: To review the literature and establish whether the BIS monitor can be used to measure depth of anaesthesia in patients with neurologic disability. Method: Databases including Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE and PubMed were searched to identify studies investigating the use of the BIS in patients with neurological disability causing atypical EEG patterns. Results: Four case reports and four observational studies were found describing patients with Alzheimer’s disease, vascular dementia, intellectual disability, epilepsy and congenitally low EEG, who were monitored with the BIS when undergoing anaesthesia. In general, these studies showed patients with neurologic disabilities score lower on the BIS even when fully aware than their non-disabled peers; however, relative changes in BIS score appear to reflect reasonably accurately changes in conscious state and likelihood of awareness. Conclusion: The BIS score fails to provide an absolute measure of level of consciousness in patients with neurological impairment and should not be relied upon as the sole measure of awareness. It can, however, provide a relative measure of change in consciousness.

“The anaesthetist and surgeon could have before them on tape or screen a continuous record of the electric activity of… [the] brain.” F. Gibbs, 1937 [1]

v6_i1_a5

Introduction

Originally, monitoring depth of anaesthesia involved the use of clinical signs considered proxies for consciousness, such as those described by Snow in 1847 and later by Guedel. [2,3] Subsequent calculations of the minimum alveolar concentration improved monitoring and reduced  the  incidence  of  awareness.  More  recently,  however,  it has been recognised that intra-operative awareness can occur independently of sympathetic responses or changes in end tidal concentration parameters. [4] Awareness under anaesthesia is defined as “consciousness under general anaesthesia with subsequent recall”, [5] which is commonly detected via patient self-reports or the use of a structured interview, such as a ‘Brice’ questionnaire. [6] The current incidence of awareness is estimated as occurring in 0.1-0.2% of surgical procedures. [7] Though uncommon, episodes of intra-operative awareness can have significant negative psychological consequences. [8] These consequences have the potential to be greater in patients with neurological disease as they may lack insight into their medical condition and the need for surgery.

The EEG was first suggested as a way to overcome the shortcomings of clinical measures of awareness in 1937. [1] Since then, there have been numerous attempts to achieve this, culminating with the production of the bispectral index (BIS) in 1996. The BIS uses a proprietary algorithm to transform the EEG into a single, dimensionless number between 0 and 100. 100 correlates to “awake”, 40 to 60 to “general anaesthesia” and 65-85 to “sedation”. The mathematics of bispectral analysis are beyond the purview of this paper but are detailed elsewhere. [9] A trial in patients at high-risk for awareness, but without neurological illness, found significant reductions in rates of intra-operative awareness, though similar successes have not been replicated elsewhere. [10,11]

Importantly, the algorithm underpinning the BIS was developed by analysing the normal electroencephalograms (EEG) of over 1000 healthy volunteers. Patients with neurologic disease, however, often have underlying structural or physiological abnormalities that manifest themselves as abnormal EEG findings. This has been demonstrated in a variety of psychiatric, degenerative and developmental disabilities. [12] Atypical EEG patterns not taken into consideration during the development of the algorithm can therefore influence BIS levels independently of the depth of anaesthesia. [13] Theoretically, this reduces the BIS’s ability to accurately measure depth of anaesthesia in patients with neurological disease. [14]

Aim

To review the literature and establish whether the BIS monitor can be used to measure depth of anaesthesia in patients with neurologic disability.

Search strategy

A search was undertaken of the medical literature. The following keywords and their alternative spellings were mapped to their medical subject headings: neurology, cognitive disability, intellectual disability, BIS, bispectral index and intra-operative monitoring. These keywords were combined with appropriate Boolean operators and used to search databases including Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE and PubMed.

Literature review

There were four case reports and four observational studies found. Conditions described in the literature were Alzheimer’s disease and vascular dementia (one observational study), intellectual disability (two observational studies), seizures (three case reports and one observational study), and congenital low amplitude EEG (one case report).

The results of a prospective observational study suggest the BIS may be of limited use in monitoring patients with Alzheimer’s disease or vascular dementia. [15] The study compared 36 patients with dementia with 36 age-matched controls. It found that patients with these conditions had an awake BIS on average of 89.1, 5.6 lower than age-matched controls with a baseline of 94.7, and below 90, considered the cut-off point indicating sedation. [16] These results indicate the BIS values corresponding to awareness validated in normal patients may not apply to those diagnosed with Alzheimer’s disease or vascular dementia. Participants in this study were not anaesthetised, so response in BIS to anaesthesia was unable to be assessed. Therefore, it could not be determined whether the BIS intervals which correspond to general anaesthesia and sedation in normal patients were applicable to Alzheimer’s patients or alternatively whether they would need to be anaesthetised to a lower BIS given their lower baseline level.

The BIS in intellectually-disabled patients has been investigated in two prospective, observational studies, though these provided conflicting results. The first compared 20 children with quadriplegic cerebral palsy and intellectual disability with 21 matched controls at a number of clinical endpoints. [17] The mean BIS of children with cerebral palsy was significantly lower at sedation (91.63 vs 96.79, p = 0.01), at an end-tidal sevoflurane concentration of 1% (48.55 vs 53.38, p = 0.03) and at emergence (90.73 vs 96.45, p = 0.032). The authors concluded validation of the BIS in children with intellectual disability may be tenuous. However, though the absolute BIS scores were different between these groups, the relative reduction in BIS score and pattern of change at increasing levels of anaesthesia was similar. The BIS may therefore not be a guide to the absolute depth of anaesthesia, but changes indicate increasing or decreasing awareness. It should be noted that this study was performed in children, for whom the BIS was not developed, as opposed to adults. The difference in EEGs between adults and children may therefore have confounded these results.

The  second  article described  a  prospective observational study  of 80 adolescent and adult patients with varying degrees of intellectual disability undergoing general anaesthesia for dental procedures. [18] The aetiology of intellectual disability varied between patients but was predominately due to autism, cerebral palsy or Down syndrome. The study found no statistically significant difference in BIS scores between patients with mild, moderate, severe or profound disability at eight different clinical endpoints (awake, induction of anaesthesia, intravenous catheter placement, tracheal intubation, start of surgery, end of surgery, awakening to commands, and tracheal extubation). The only statistically significant finding of the study was that patients with more severe intellectual disability took longer to emerge from anaesthesia. The BIS monitor, however, accurately predicted this and provided an additional clue to the anaesthetist of the time required until extubation. These results indicate that intellectual disability does not affect the BIS and support the authors’ hypothesis that the BIS score is “a measure of global neuronal function, not a measure of the aberrant neuronal connection” [18] and could therefore be applied to these patients.

Though these two studies provide conflicting results on whether intellectual  disability  affects  the  absolute  BIS  level,  both  provide good evidence that relative reductions in BIS scores correlate well with increasing depth of anaesthesia in these patients. The BIS may therefore have a role in monitoring changes in conscious states.

Despite the known ability of epilepsy to cause significant derangement of the EEG, only three case reports were found which dealt with this in relation to the BIS. The first describes a patient with pre-existing epilepsy undergoing surgery. [19] Despite no clinical change, the patient’s BIS score dropped sharply from 40 to 20 before recovering every five minutes. This occurred over a period of hours until the raw EEG was checked and found to show epileptiform activity. Anticonvulsants were given at which point the BIS stabilised. In another report, seizures were evoked using photic stimulation. [20] Despite the patient remaining conscious, the BIS level dropped to 63 during the seizure. In the third case report, a patient in status epilepticus had a measured BIS of 93 despite being unconscious. [21] This dropped to 23 with control of the seizures. These reports provide strong support for the assertion that “BIS values may not accurately reflect the actual level of consciousness when abnormal EEG activity is evoked in epileptic patients”. [20]

In these studies of epilepsy, when patients were not ictal, BIS scores provided measures of depth of anaesthesia that were as accurate as would be expected in non-epileptic patients. The seizures themselves were heralded by large, rapid changes in the BIS, as was their recovery. Epilepsy is not therefore a contraindication to monitoring with the BIS, but anaesthetists should be aware that abnormal BIS scores may be the result of seizures rather than changes in depth of anaesthesia. Furthermore, in instances of sudden changes in the BIS the raw EEG can be checked to determine if the change is due to seizure activity.

The final description of a neurological condition affecting the BIS found in the literature was a congenital, non-pathological low amplitude EEG. In one case report, a man with this condition, despite being fully conscious, had a recorded BIS of 40. [22] This is on the low edge of the level considered ideal for general anaesthesia. As many as 5-10% of the population may show this rhythm when attached to an EEG, which is genetically determined and not associated with any pathology. [23] The current BIS algorithm is incapable of distinguishing awareness from anaesthesia in these patients.

Conclusion

A search of the literature showed almost all neurological conditions which were studied cause abnormal BIS levels. Alzheimer’s disease, vascular dementia, intellectual disability, epilepsy and congenitally low amplitude EEG were studied and all disease states, except intellectual disability, in which the results were conflicting, were shown to affect the BIS. It is far from clear whether the BIS may have a role in intra- operative awareness in addition to standard clinical measures in patients  with  neurological  disease.  The  use  of  BIS  in  these  cases may therefore mislead the anaesthetist rather than help them. If the anaesthetist does choose to use the BIS to monitor these patients, the BIS should be measured at baseline as the relative reduction in BIS scores may be more important than the absolute value in these patients. Given the lack of published data on this subset of patients, further controlled trials or subgroup analysis of existing trials that compares the use of the BIS against anaesthetic outcomes in patients with neurological disease would be a worthy avenue of future research.

Acknowledgements

None.

Conflict of interest

None declared.

Correspondence

J Gipson: jsgip2@student.monash.edu.au

References

[1] Gibbs FA, Gibbs EL, and Lennox WG. Effect on the electro-encephalogram of certain drugs which influence nervous activity. Arch Intern Med 1937;60:154-66.

[2] Snow J. On the inhalation of the vapor of ether in surgical operations: containing a description of the various stages of etherization and a statement of the result of nearly eighty operations in which ether has been employed in St. George’s and University College Hospitals. London: Churchill J; 1847.

[3] Guedel A. Inhalational anesthesia, A fundamental guide. New York: Macmillan; 1937. [4] Domino KB, Posner KL, Caplan RA, Cheney FW.  Awareness during anesthesia: a closed claims analysis. Anesthesiology. 1999;90(4):1053-61.

[5] American Society of Anesthesiologists Task Force on Intraoperative, A., Practice advisory for intraoperative awareness and brain function monitoring: A report by the American Society  of  Anesthesiologists  Task  Force  on  Intraoperative  Awareness.  Anesthesiology. 2006;104(4):847-64.

[6] Pandit JJ, Andrade J, Bogod DG, Hitchman JM, Jonker WR, Lucas N et al. 5th National Audit  Project  (NAP5)  on  accidental  awareness  during  general  anaesthesia:  protocol, methods, and analysis of data. Br J Anaesth. 2014;113(4):540-8.

[7] Myles PS, Williams DL, Hendrata M, Anderson H, Weeks AM. Patient satisfaction after anaesthesia and surgery: results of a prospective survey of 10,811 patients. Br J Anaesth. 2000;84(1):6-10.

[8] Lennmarken C, Bildfors K, Eulund G, Samuelsson P, Sandin R. Victims of awareness. Acta Anaesthesiol Scand, 2002;46(3):229-31.

[9] Sigl JC, Chamoun NG. An introduction to bispectral analysis for the electroencephalogram. J Clin Monit. 1994;10(6):392-404.

[10] Myles PS, Leslie K, McNeil J, Forbes A, Chan MT. Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet. 2004;363(9423):1757-63.

[11] Avidan MS, Zhang L, Burnside BA, Finkel KJ, Searleman AC, Selvidge JA et al. Anesthesia awareness and the bispectral index. N Engl J Med. 2008; 358(11):1097-108.

[12]  Hughes  JR,  John  ER.  Conventional  and  quantitative  electroencephalography  in psychiatry. J Neuropsychiatry Clin Neurosci. 1999;11(2):190-208.

[13] Dahaba AA. Different conditions that could result in the bispectral index indicating an incorrect hypnotic state. Anesth Analg. 2005;101(3):765-73.

[14] Bennett C, Voss LJ, Barnard JP, Sleigh JW. Practical use of the raw electroencephalogram waveform during general anesthesia: the art and science. Anesth Analg. 2009;109(2):539-50.

[15] Renna M, Handy J, Shah A. Low baseline Bispectral Index of the electroencephalogram in patients with dementia. Anesth Analg. 2003;96(5):1380-5

[16] Johansen JW Sebel PS, Development and clinical application of electroencephalographic bispectrum monitoring. Anesthesiology. 2000;93(5):1336-44.

[17] Choudhry DK, Brenn BR. Bispectral index monitoring: a comparison between normal children and children with quadriplegic cerebral palsy. Anesth Analg. 2002. 95(6):1582-5 [18] Ponnudurai RN, Clarke-Moore A, Ekulide I, Sant M, Choi K, Stone J et al. A prospective study of bispectral index scoring in mentally retarded patients receiving general anesthesia. J Clin Anesth. 2010;22(6):432-6.

[19] Chinzei M, Sawamura S, Hayashida M, Kitamura T, Tamai H, Hanaoka K. Change in bispectral index during epileptiform electrical activity under sevoflurane anesthesia in a patient with epilepsy. Anesth Analg. 2004;98(6):1734-6

[20] Ohshima N, Chinzei M, Mizuno K , Hayashida M, Kitamura T, Shibuya H et al. Transient decreases in Bispectral Index without associated changes in the level of consciousness during photic stimulation in an epileptic patient. Br J Anaesth. 2007;98(1): 100-4.

[21]  Tallach  RE,  Ball  DR,  Jefferson  P.  Monitoring  seizures  with  the  Bispectral  index. Anaesthesia. 2004;59(10): 1033-4.

[22] Schnider TW, Luginbuhl M, Petersen-Felix S, Mathis J. Unreasonably low bispectral index values in a volunteer with genetically determined low-voltage electroencephalographic signal. Anesthesiology. 1998;89(6):1607-8.

[23] Niedermeyer E. The normal EEG of the waking adult, in Electroencephalography : basic principles, clinical applications, and related fields. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health; 2011. 1275p.

Categories
Letters

Surgical hand ties: a student guide

Surgical  hand  ties  are  a  procedural  skill commonly employed in surgery; however, student    exposure    to    practical    surgical experience  is  often  limited.  Students are therefore often excited at the opportunity to learn these skills to practise for themselves. Often the only opportunities to formally learn these skills come in the form of workshops presented at student conferences or run by university special interest groups.

Having attended such surgical skills workshops I have noticed the difficulty demonstrators and students have had in teaching and learning learn and master hand ties.

In addition to being an individual resource, this guide was also created for use in a workshop setting. Ideally, a demonstrator would show the students the basic steps involved in hand ties. The guide could then be used to reinforce this learning, where the student can practise with the sutures in their hands while following the steps using a combination of pictures, text, and memory aids. This would also have the benefit of letting the demonstrator help students with more specific questions on technique, rather  than  repeating  the  same the skill of surgical hand ties. I felt this was the product of two things: the difficulty the tutors had in demonstrating the small movements of the fingers to an audience; and the students’ difficulty with remembering each step later. Therefore, I combined an easy to follow graphic with some helpful memory aids into a simple resource to help medical students demonstration multiple times.

The overall aim of this guide is to make the process of learning and teaching surgical hand ties to students easier, and to improve recall and proficiency for students performing the skill through the use of simplified steps and diagrams.

v6_i1_a2a v6_i1_a2b

Acknowledgements

None.

Conflict of interest

None declared.

Correspondence

J Ende: jesse@ende.com.au