Descriptions of postoperative neurobehavioral disturbances suffer the same classification problems that affected all psychiatry until uniform systems of classification were introduced in the 80’s. Many investigators from differing medical specialties have tried to address the causes, diagnosis and management of these conditions. However, there is an historical lack of uniformity in the classification of the conditions being described and overlaps exist between similar but unrelated pathologies.1 Some authors fail to specifically define the psychological condition they are describing; fail to use standard classification of mental illness or fail to distinguish between, for example, acute postoperative psychoses, postoperative delirium, depression, POCD and drug induced acute psychosis.2 Furthermore the component parts necessary for defining a specific diagnosis can differ between countries.

With the advent of symptom-based diagnoses there is a growing standardization of the classification of psychiatric diagnoses.3 Two common systems for classifying mental disorders are used by professionals at present. Chapter V of the International Classification of Diseases (ICD-10) produced by the World Health Organization (WHO).4 And The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) produced by the American Psychiatric Association (APA).5 The Diagnostic and Statistical Manual of Mental Disorders v 5 claims to be
“the most comprehensive, current, and critical resource for clinical practice available to today’s mental health clinicians and researchers of all orientations. DSM-5 is used by health professionals, social workers, and forensic and legal specialists to diagnose and classify mental disorders, and is the product of more than 10 years of effort by hundreds of international experts in all aspects of mental health. The criteria are concise and explicit, intended to facilitate an objective assessment of symptom presentations in a variety of clinical settings- inpatient, outpatient, partial hospital, consultation-liaison, clinical, private practice, and primary care.”

There are numerous causes of acute psychosis that are recognized as hazards of treatment in hospital. 6 An association between recent surgery and neurobehavioral disturbances (POND) is recognized as a common subgroup.7

Some authors recognize three distinct forms of POND: emergence delirium, postoperative delirium, and postoperative cognitive decline (POCD). Unlike delirium, postoperative cognitive decline is a controversial diagnosis, which is not described in the Diagnostic and Statistical Manual of Mental Disorders. There are recognized predisposing factors, including age, length of surgery and severity of illness.8 A further sub-group common to each is “drug-induced” psychosis (substance-induced delirium, substance intoxication delirium).2 Schultz et al list 500 medications implicated in the genesis of acute drug induced psychoses.9 The ways in which these 500 drugs work on the body is so dissimilar one can assume that the mechanisms for causing neurobehavioral disturbances are equally varied. 10 However it is an error to assume all adverse postoperative outcomes are drug induced.

Postoperative disturbances have even been described in the pre anesthetic era and thus they may occur in the absence of any medication. The condition may be the result of abnormal physiology rather than an abnormal response to medications. Parikh and Chung write that acute postoperative psychosis was recognized as early as the 16th century and was first documented in 1819.11

The reported incidence of all neurological disturbances depends on, amongst other things, the patient’s age, their comorbidities, the medical condition being treated, the operation site and the type of neurobehavioral outcome. The incidence of delirium following hip repair in the elderly, for example, has been reported to be as high as 61% of all patients.12 However, in one study of 419 recovery room incidents, no episodes of POND were reported to have occurred. This is at variance with studies mentioned previously. It may be that the study did not seek this phenomenon or, in the absence of appropriate training, this may have been failure of recognition rather than non-occurrence. 13 Alternatively this disparity may accurately reflect non-occurrence during the immediate postoperative period. The condition may then only become apparent on the postoperative wards after leaving the recovery or PACU. Intensive care unit psychosis is a well-recognized phenomenon. This condition is probably no different from acute postoperative psychosis but is uniquely identified because of its location and capacity to inflict ongoing damage.

Various websites, such as are devoted to providing information to patients, relatives and medical staff. Hallucinations and delusions, possibly induced by sedatives, rather than factual events, were the most traumatizing aspects of intensive care among in one study and may have led to the development of PTSD. 14 Recent studies indicate that no sedation (after intubation) is most beneficial for patients rather than fluctuating levels of sedation. 15

Despite the increasing awareness of post operative neurological disturbances (POND) the management of acute psychotic reactions is not part of the core competencies required by nurses or anesthesiologists working in post anesthesia care units (PACU).16,17,18

Excellent training modules do exist, for example at accessed Tuesday, July 29, 2014. This type of learning module could be usefully deployed to anaesthetic and surgical trainees.

Episodes of POND are usually self-limiting and patients are assumed to recover without lasting harm, but this may not always be true.The significance of an acute postoperative psychosis is poorly understood and awareness of its diagnosis and knowledge of its management are critical to provide better care to patients.19 Patients suffering from acute postoperative delirium are capable of extreme self-harm and the condition should be considered a medical emergency. Relatives who notice significant changes in patients psyche should never be ignored.


    • 1. James Scott, Postoperative psychosis in the aged. The American Journal of Surgery Volume 100, Issue 1, July 1960, Pages 38–42
    • 2. Olympio MA. Postanesthetic delirium: historical perspectives. J Clin Anesth. 1991 Jan-Feb;3(1):60-3.
    • 3. Mayes R And Horwitz Av. DSM-Iii And The Revolution In The Classification Of Mental Illness. Journal of the History of the Behavioral Sciences, Vol. 41(3), 249–267 Summer 2005. Published online in Wiley Interscience ( DOI 10.1002 /jhbs.20103
    • 4. Tuesday, July 1, 2014
    • 5.Diagnostic and Statistical Manual of Mental Disorders FIFTH EDITION
    • 6. Abdullah MS1, Al-Waili NS, Baban NK, Butler GJ, Sultan L. Postsurgical psychosis: case report and review of literature. Adv Ther. 2006 Mar-Apr;23(2):325-31.
    • 7. Deiner S and J. H. Silverstein JH. Postoperative delirium and cognitive dysfunction. Br. J. Anaesth. (2009) 103 (suppl 1): i41-i46. doi: 10.1093/bja/aep291
    • 8. Sanders Rd et al. Anticipating and managing postoperative delirium and cognitive decline in adults BMJ 2011; 343 doi: (Published 20 July 2011) Cite this as: BMJ 2011;343:d433
    • 9. Schultz, U.; Idelberger, R.; Rossaint, R.; Buhre, W., 2002: Central anticholinergic syndrome in a child undergoing circumcision. Acta Anaesthesiologica Scandinavica 46(2): 224-226
    • 10. Lieberman, Jeffrey A.; Kinon, Bruce J.; Loebel, Antony D. Dopaminergic Mechanisms in Idiopathic and Drug-Induced Psychoses. Schizophrenia Bulletin, Vol 16(1), 1990, 97-110.
    • 11. Parikh S and Chung F. Postoperative delirium in the elderly. Anesth Analg 1995; 80: 1223-32.
    • 12. Sultan S S. Assessment of role of perioperative melatonin in prevention and treatment of postoperative delirium after hip arthroplasty under spinal anesthesia in the elderly Saudi J Anaesth. 2010 Sep-Dec; 4(3): 169–173.
    • 13. Kluger MT1, Bullock MF Recovery room incidents: a review of 419 reports from the Anaesthetic Incident Monitoring Study (AIMS) Anaesthesia. 2002 Nov;57(11):1060-6…
    • 14. Wade DM, Brewin CR, Howell DC, White E, Mythen MG, Weinman JA. Intrusive memories of hallucinations and delusions in traumatized intensive care patients: An interview study. Br J Health Psychol. 2014 Jun 18. doi: 10.1111/bjhp.12109. [Epub ahead of print]
    • 15. Svenningsen H. Associations between sedation, delirium and post-traumatic stress disorder and their impact on quality of life and memories following discharge from an intensive care unit. Dan Med J. 2013 Apr; 60(4):B4630.
    • 16. Kluger MT, Bullock MF. Recovery room incidents: a review of 419 reports from the Anaesthetic Incident Monitoring Study (AIMS). Anaesthesia. 2002 Nov;57(11):1060-6.
    • 17. Guidelines. Immediate post-anaesthesia recovery 2013. Association of Anaesthetists of Great Britain and Ireland. Anaesthesia 2013, 68, 288–297.
    • 18. UK National Core Competencies for Post-anaesthesia Care 2013 at
    • 19. Morgado P., Gonçalves J. P-404 – Postoperative psychosis – a case reportEuropean Psychiatry Volume 27, Supplement 1, Page 1, 2012
This condition is poorly described in the medical literature as it is spread over journals from a wide variety of differing specializations. It may be useful to explore the literature that describes a similar psychiatric disturbance with an equal capacity to cause patients harm. Postoperative psychosis (one of several different manifestations of POND) may be described as an acute first-episode psychosis (FEP).This severe reaction is uncommon, especially in the absence of a previous history of mental illness. However, obtaining a history of previous psychiatric illness does not form part of a standard anesthetic pre-assessment. Furthermore, warning patients of potential negative neurobehavioral outcomes does not commonly form part of pre-operative discussions between either the surgeon or the anesthesiologist and the patient. Unfortunately the risk of suicidal behavior is relatively high in first-episode psychosis (FEP) patients.2Early detection of psychotic disorders and implementing treatment earlier in the course of illness reduces mortality.3 The diagnosis of an FEP or Postoperative delirium or psychosis in the immediate postoperative period should, in our opinion, be considered a medical emergency because of the severity of possible outcomes.In order for valid informed consent to be given, a competent individual who has received the necessary information must be able to understand, retain, use or weigh up that information and be able to communicate their wishes. A person must first be made aware of all risks. It has been argued that it is part of the duty of care of clinicians to be aware of these risks and be able to adequately communicate them to patients.4Any liability for failing to warn patients of the risk of postoperative neurobehavioral changes remains untested in the courts. However failing to warn patients of possible adverse neurobehavioral outcomes that create lasting morbidity or death may, in the future, be considered to be negligence in some jurisdictions.5 In Chester v. Afshar the claimant had suffered back pain for 6 years. She elected to have surgical treatment.This surgery had a small but measurable risk associated with it of further pain and nerve damage. Her consultant neurosurgeon Mr. Afshar was under a duty to warn her of all risks, including rare but significant ones, but failed to do so. The claimant had the operation and unfortunately it worsened her condition. The trial judge found that the surgeon had not been negligent in performing the operation but his failure to warn her of the risk was a breach of duty.6 It can also be argued that a duty of care will extend to hospital administrators who are responsible for training and staffing levels in areas where this outcome is a possibility, like post anesthesia care units (PACU). In California safe staffing levels are not contentious as law set them in 2004.7


    • 1. Yale School of Medicine 7/27/14
    • 2. Pompili M, Serafini G, Innamorati M, Lester D, Shrivastava A, Girardi P, Nordentoft M Suicide risk in first episode psychosis: a selective review of the current literature. Schizophr Res. 2011 Jun;129(1):1-11. doi: 10.1016/j.schres.2011.03.008. Epub 2011 May 6
    • 3. Editorial. Can Early Detection of Psychosis Prevent Suicidal Behavior? Am J Psychiatry 163:5, May 2006 769
    • 4. Bajwa SJ1, Jindal R, Kaur J, Singh A. Psychiatric diseases: Need for an increased awareness among the anesthesiologists. J Anaesthesiol Clin Pharmacol. 2011 Oct;27(4):440-6. doi: 10.4103/0970-9185.86572.
    • 5. Chester v Afshar [2004] UKHL 41 Pt 2 The duty to warn patients about risk. Monday, June 30, 2014
    • 6. Chester (Respondent) v. Afshar (Appellant) [2004] UKHL 41
    • 7. Aiken L, Sloane D et al (2010) Implications of the California Nurse Staffing Mandate for Other States. Health Services Research. 45 (4) 904-21.
If there is an association between anaesthesia and POND an obvious question is to ask do we need anaesthetics? The simple but improbable answer is no, we do not always need anaesthesia for all surgery or interventions. Anaesthesia may be induced by the administration of anaesthetic gases or the intravenous injection of drugs.First however, it is necessary to define our terms. The word anaesthesia originates from Greek anaisthēsia, from an- ‘without’ + aisthēsis ‘sensation’.1 Anesthesia may be general anaesthesia, which affects the whole body, or local anaesthesia that by various means and the use of local anesthetic agents (e.g. lidocaine or lignocaine), produces numbness of the operation site or limb.Analgesia is the lack of pain.The term anesthetist refers to any anaesthesia practitioner, usually a physician specialising in anaesthesia (e.g. UK and Australasia) or, in some countries (e.g. USA and Scandinavia), a certified nurse anesthetist. In these latter locations a physician anesthesiologist commonly supervises the certified nurse anaesthetist.

The question “do we need anaesthesia” needs to be asked because of increasing concerns regarding the neurotoxicity (damage to brain cells) of general anaesthetic agents.2 This is a highly contentious issue, especially in the case of newborn children3 and the elderly.4 The concerns of this latter group of international experts are best summarized in their own words.

“Although previously considered entirely reversible, general anaesthesia is now being viewed as a potentially significant risk to cognitive performance at both extremes of age. A large body of preclinical as well as some retrospective clinical evidence suggest that exposure to general anaesthesia could be detrimental to cognitive development in young subjects, and might also contribute to accelerated cognitive decline in the elderly.”

They concluded:

“Mounting evidence exists from preclinical studies that general anaesthetics are powerful modulators of neuronal development and function. Although evidence from clinical studies in paediatric and geriatric anaesthesiology is emerging, it is important for this line of research to be expanded. As general anaesthesia often cannot be avoided regardless of patient age, it is important to understand the complex mechanisms and effects involved in anaesthesia-induced neurotoxicity, and to develop strategies for avoiding or limiting potential brain injury. Studies towards those ends will permit more definitive conclusions about potential neurotoxicity in humans, and facilitate the establishment of recommendations to guide clinical practice as definitive clinical data are likely to be elusive.”

Some authors have warned it is important we do not “throw the baby out with the bath water”.5 To understand what that means it is important to understand what would happen if we did not have anaesthetics. Evidence can be sought from the period in history where surgery was undertaken without the routine use of anaesthesia.

Until 1846, when contemporary anesthesia started, opium and alcohol, neither of which are anesthetics, were the only agents amongst a myriad of contenders, that were regarded as reliable means of producing pain relief (analgesia) but they were not able to induce unconsciousness except in toxic doses. Following the introduction of anesthesia its use was adopted piecemeal in various countries more or less at the whim of individual surgeons. To answer the question “do we need anaesthetics?” it is instructive to look at the scope of surgery before and during the advent of anesthesia and the advances in surgical practice made possible following the widespread adoption of anesthesia.

There are numerous sources of such information, including contemporaneous battlefield accounts of the treatment of injuries that occurred during the Crimean (1853 –1856) and American Civil wars (1861 – 1865). It was during these wars, contemporaneous with the development of anaesthetic techniques, that anesthesia essentially came of age.

Prior to the advent of anesthesia, elective surgery was rarely performed and only as a last resort. Statistics for the Massachusetts General Hospital (MGH) illustrate representative surgical activity in the first half of the 19th century in North America. In the 25-year epoch, from 1821 to 1846, the annual reports of the MGH recorded 333 surgeries, representing barely more than one case per month.6 Between 1836 and 1846, a total of 39 surgical procedures were performed at that hospital annually.

Under many modern licensing permits these numbers of surgical cases are so low they would preclude a contemporary hospital’s recognition as a place where surgery may be undertaken safely. Furthermore, the numbers are so low they would inhibit the development of, what now would be considered minimum, surgical skills. Documentation of operative experience is an essential component of all general surgery residencies (training programs). One 5-year program, for example, sets the following standards. The minimum number of operations that should be performed as surgeon: 750 with at least 150 of these as chief surgeon.7 In the aforementioned 25 year period at MGH there would have been too few surgical procedures to adequately train a single contemporary surgical trainee.8

Following the introduction of anaesthesia, from 1847 to 1857, the annual average of surgeries in this same hospital increased to 189 procedures, mostly amputations. Opening abdomens or chests was rare, reflecting battlefield practices, where most surgeons gained first or second hand training and experience. Over the next 20 years and with the introduction of antisepsis and asepsis the volume of surgery increased 10 fold. Between 1894 and 1904, for example, an average of 2,427 procedures were done annually at this hospital and, by 1914, more than 4,000.9 By the end of the American civil war over 100,000 surgical operations had been performed.

One interesting historical note observes that during the early period of the war some wounded soldiers preferred to operate on themselves rather than subject themselves to the attention of novice surgeons. However, towards the end of this period, with increased knowledge and experience most of these operations (amputations) occurred with the clear benefit of anaesthesia.10 It is currently estimated that 234·2 (95% CI 187·2—281·2) million major surgical procedures are undertaken every year worldwide, each requiring an anaesthetic.11

Case histories

Two historical case histories help illustrate the benefits, though no absolute necessity, of anaesthesia and the association between surgery and psychological disturbances. Both occurred during a period when anaesthesia was considered optional rather than a necessity. In 1863, after being shot through the arm by his own pickets, Stonewall Jackson required the removal of his left arm. When a chloroform-soaked cloth was placed over his nose, the Confederate general, in great pain, is reported to have said, “What an infinite blessing,” before losing consciousness.12 Unfortunately he died 5 days later from a (possibly) unrelated chest infection.

An equally unlucky Private Winchell required the same procedure, but the amputation was performed whilst surgical assistants were holding him down, without him benefiting from anaesthesia. Postoperatively he had an understandably rough recovery, receiving no analgesia (pain relief) and surviving a mental state fluctuating between delirium and coma. Private Winchell lived another thirty years and was subsequently able to narrate his dreadful experiences. 13

Not only did anesthesia relieve patients of unbearable suffering it also relieved fellow patients and hospital staff of the trauma of hearing the process from afar or having to witness painful surgery directly. Other advantages followed. Surgical speed was no longer an absolute pre-requisite and greater care could be exercised, reducing blood loss, complication rates and increasing surgical precision. The increasing numbers of patients willing to subject themselves to surgery allowed for the acquisition of greater surgical skills whilst the presence of a skilled practitioner, trained in anesthesia and dedicated to the patients intra-operative welfare, relieved surgeons of these distractions.


    • 1. Oxford English Dictionary
    • 2. Vlisides P1, Xie Z. Neurotoxicity of general anesthetics: an update. Curr Pharm Des. 2012;18(38):6232-40.
    • 3. McCann ME, Soriano SG. Is anesthesia bad for the newborn brain? Anesthesiol Clin. 2009 Jun;27(2):269-84. doi: 10.1016/j.anclin.2009.05.007.
    • 4. Jevtovic-Todorovic V1, Absalom AR, Blomgren K, Brambrink A, Crosby G, Culley DJ, Fiskum G, Giffard RG, Herold KF, Loepke AW, Ma D, Orser BA, Planel E, Slikker W Jr, Soriano SG, Stratmann G, Vutskits L, Xie Z, Hemmings HC Jr. Anaesthetic neurotoxicity and neuroplasticity: an expert group report and statement based on the BJA Salzburg Seminar. Br J Anaesth. 2013 Aug;111(2):143-51.
    • 5. Soriano SG, Loepke AW. Let’s not throw the baby out with the bath water: potential neurotoxicity of anesthetic drugs in infants and children. J Neurosurg Anesthesiol. 2005 Oct;17(4):207-9.
    • 6. Sullivan JT “Surgery before anesthesia” American Society of Anesthesiologists newsletter, September, 1996, Vol. 60, No. 9, Pages 8-10.
    • 7. Cedars Sinai 7/19/14
    • 8. Joint Committee of Surgical Training 7/19/14
    • 9. The Truth About Civil War Surgery By Alfred J. Bollett 7/13/14.
    • 10. NIH U.S. National Library of Science 7/19/14
    • 11. Weiser TG et al. An estimation of the global volume of surgery: a modelling strategy based on available data. The Lancet. 2008: 372; 9633: 139 – 144. doi:10.1016/S0140-6736(08)60878-8
    • 12. Albinemail MS. In praise of anesthesia: Two case studies of pain and suffering during major surgical procedures with and without anesthesia in the United States Civil War-1861–65. Scandinavian Journal of Pain. Volume 4, Issue 4, Pages 243–246, October 2013
    • 13. Stevens, C.A. Wounded and a prisoner. Berdan’s United States Sharpshooters in the Army of the Potomac, 1861–1865. Price McGill Co, St. Paul; 1892

Anaesthetics are considerably safer now then it was 150 years ago. Compared to other specialties it is often held to be a shining example of improved patient safety. Gaba (2000) summarized this in the following manner.1

“Anesthesiology is acknowledged as the leading medical specialty in addressing patient safety.Anaesthesia is safer than ever owing to many different types of solutions to safety problems.Solution strategies have included incorporating new technologies, standards, and guidelines, and addressing problems relating to human factors and systems issues.The multidisciplinary Anesthesia Safety Foundation was a key vehicle for promoting patient safety.”A crucial step was institutionalizing patient safety as a topic of professional concern.”

The USA based Institute of Medicine (IOM) asserted in 1999: “Anesthesia is an area in which very impressive improvements in safety have been made.” The Committee stated that anesthesia mortality rates have decreased from 2 deaths per 10,000 anesthetics administered in the 1980s to about 1 death per 200,000 to 300,000 anesthetics administered today.2 Other authors, in contrast, state that this improvement in safety records is overstated by several orders of magnitude.3 The truth must lie somewhere between the ranges of figures offered by different authors. Suffice it to say most anesthetists will complete an entire career in anesthesia without experiencing a single unexpected death (mortality) during surgery.

Although anesthesiology has made important strides in improving patients’ physical safety, there is still some way to go, especially with regard to non-fatal postoperative illness (morbidity), including neurobehavioral disturbances. Improving our understanding of how anaesthetics work may help in this regard.

Case history

Despite all the improvements in patient safety, an anaesthetic may, rarely, result in a non-fatal but significant illness or postoperative neurobehavioural disturbance. Various example case histories are in the public domain. Carina Storrs in Scientific American reported on the case of Susan Baker, an 81-year-old professor of Public Health at the Johns Hopkins Bloomberg School. She underwent three hours of general anesthesia whilst having back surgery. Surgery and recovery progressed uneventfully until the evening, 6 hours after surgery. During the night deterioration in her mental function occurred and she began to hallucinate that a fire raged through the hospital toward her room. Understandably terrorized she repeatedly sought help from the nursing staff. By the next day she was back to her usual self. “It was the most terrifying experience I have ever had,” she is reported to have said.4

Baker’s experience is typical of the rare and unusual postoperative disturbance that is reported as postoperative delirium. In addition to hallucinations patients become confused and may suffer memory loss. They may forget why they are in the hospital, be unable to respond to direct questioning and when they do respond the answer bears no relation to the question. Fortunately such disturbances usually resolve within a short period of time (1-2) days.

This specific type of postoperative neuro-behavioural disturbance, though severe, is fortunately infrequent. It is precisely because of its infrequency that so little is known about it.

Some authors believe that post operative psychosis or delirium may occur as a result of a period of intraoperative awareness – a period where the level of general anaesthesia is insufficient for the degree of surgical stimulation. Patients may be able to recall events that occur during surgery and indeed be aware of the surgeon’s actions. Patients’ responses vary. Some may be comfortable, others distressed or others in severe pain. This latter group may rapidly suffer from PTSD that of itself, induces delirium.

In answer to the question “Do we need an anaesthetic?” the answer is an unequivocal yes, for major surgery. Some surgery and certain other interventions may be adequately performed with the benefits of conscious sedation or local anaesthesia. To this may be added an important caveat, that is the need for an experienced, well trained anaesthetist to administer the anaesthetic and adequate numbers of trained staff to manage the postoperative period.

The purpose of this website is to focus on such untoward events, highlight their existence and encourage patients, carers, clinicians and medical educators to fill the knowledge void that surrounds these events.


    • 1. Gaba DM: Anesthesiology as a model for safety in health care. BMJ 2000; 320: 785–8
    • 2. Kohn LT, Corrigan JM, Donaldson MS: To Err Is Human—Building a Safer Health System. Washington, National Academy Press, 1999.
    • 3. Lagasse, R S. Anesthesia Safety: Model or Myth?: A Review of the Published Literature and Analysis of Current Original Data. Anesthesiology: 2002: 97 (6) ;1609-1617. Review Article.
    • 4. The Hidden Dangers of Going Under. Anesthesia may have lingering side effects on the brain, even years after an operation Mar 18, 2014. Carina Storrs

An alternative to general anaesthesia may be offered to patients who wish to avoid general anaesthesia but are about to undergo an investigation or procedure that may be too uncomfortable, painful or otherwise intolerable to be managed with the use of local anaesthesia and reassurance alone. The alternative is conscious sedation (CS).

Common examples of procedures that are suitable for this technique are dental procedures or endoscopic examinations of the gastro-intestinal tract (e.g. colonoscopy, gastroscopy). In some circumstances CS may be the preferable technique to general anaesthesia, e.g. mechanical embolus removal in cerebral ischemia1 , or certain procedures undertaken in hospital Emergency departments.2

The aims of sedation during diagnostic or therapeutic procedures include reducing fear and anxiety, augmenting pain control and minimising movement. The importance of each of these aims will vary depending on the nature of the procedure and the characteristics of the patient.3

Conscious sedation is defined by SAAD (Society for the Advancement of Anaesthesia in Dentistry) as:

“A technique in which the use of a drug or drugs produces a state of depression of the central nervous system enabling treatment to be carried out, but during which verbal contact with the patient is maintained throughout the period of sedation. The drugs and techniques used to provide conscious sedation for dental treatment should carry a margin of safety wide enough to render loss of consciousness unlikely. The level of sedation must be such that the patient remains conscious, retains protective reflexes, and is able to respond to verbal commands.” 4

When planning a procedure under conscious sedation it is always ideal for existing staff and facilities to be of a standard suitable for handling the administration, maintenance and recovery from general anaesthesia.5 Some procedures may invoke sufficient discomfort or anxiety as to be no longer suitable for continuing under conscious sedation. Furthermore, it is not uncommon for patients receiving a steady dose of sedative medication required for conscious sedation to transition to unconscious sedation – otherwise referred to as general anaesthesia.

The general standards that apply are usefully defined by SAAD. 6 In the UK specific standards concerning the necessary facilities required to conform to clinician’s duty of care may be found in Guidance for Commissioning NHS England Dental Conscious Sedation Services. A Framework Tool. May 2013. 7

Conscious sedation has a long history in association with dental surgery. Initial high success rates with few complications were rapidly replaced by a rising number of critical injuries and deaths when the technique was employed by inadequately trained enthusiasts. Avoidable morbidity and mortality, precipitated directly from inappropriate training and lack of knowledge of the effects of sedative drugs, were identified by research and audit. Failure of recognition and treatment of sedation-related complications was the single most important factor in failures to rescue. 8 Poor outcomes and high mortality rates invoked two responses in the UK.

The first response in 1971 was a badly conceived draconian attempt to ban the technique in the UK, despite its previous successes. It was felt to be inappropriate to have the person monitoring the patient to also be the person operating on the patient.

The second, more rational, response was to analyse the safety of conscious sedation and develop best practice techniques and standards of care. Combining these analyses and identifying best practices into mandatory training courses for practitioners wishing to employ these techniques has turned a hazardous undertaking into a safe procedure. 9 Whatever constitutes “best practice” is under constant review and, where possible, evidence based. In the absence of significant evidence, it is formed from expert consensus.

Various professional bodies in the UK listed below review and publish their findings on a regular basis.

Because the transition from moderate conscious sedation to deep sedation (or early general anaesthesia) is unpredictable, preparing a patient for this procedure requires the same level of attention to detail as preparing the operating room, anaesthetic drugs and equipment and monitoring devices. In other words patients should undergo the full preoperative assessment enjoyed by a patient heading for general anaesthesia. Failure to comply with this simple safety precaution features fully in reports of adverse outcomes of conscious sedation.10,11,12,13

Levels of sedation, how do you know they are not anaesthetised?

Sedation is a continuum between minimal sedation and deep sedation. The different levels may be defined and published by licencing authorities – for example Texas State Board Of Dental Examiners publishes their Anesthesia Permit Regulations and defines 4 levels of sedation.14 Interestingly these standards (operator anaesthetist) would probably not be acceptable in the UK.

The American Society of Anaesthesiologists has also published a 3 level scale for sedation based on patients’ levels of responsiveness, which many practitioners find useful. It is important to emphasise that the first two levels of sedation are acceptable; the last (deep sedation) is not. Some experts would regard this phase as the onset of general anaesthesia rather than the late stage of sedation, especially as the patient may no longer be considered conscious. With increasing depth of sedation or reduction in responsiveness comes an increased risk of a patient being able to maintain self-protective reflexes – like maintaining their own airway. Rescuing a patient from this state of lost reflexes easily falls within the clinical competencies of an experienced anaesthesiologist or anaesthetist. Others may find rescue slow or impossible.

Sedation levels for adult patients:

Minimal sedation/ relaxation
Moderate sedation/analgesia (‘Conscious sedation’)
Deep sedation/analgesia
ResponsivenessNormal response to verbal stimulationPurposeful response to verbal or tactile stimulationPurposeful response after repeated or painful stimulation
AirwayUnaffectedNo intervention requiredIntervention may be required
Spontaneous ventilationUnaffectedAdequateMay be inadequate
Cardiovascular functionUnaffectedUsually maintainedUsually maintained

Gastrointestinal endoscopy

Endoscopy, using a flexible camera to visualise either end of the gut is very common and very safe, in the right hands. It is often undertaken with the benefit of conscious sedation, as they can be an uncomfortable or painful experience. The absence of an effective sedation and analgesia service discourages attendance especially for gut surveillance programs. Fear, pain, embarrassment and discomfort are common reasons for patients avoiding colonoscopy.15
However, having accepted a conscious sedation procedure to facilitate endoscopy a patient may be exposed to different set of risks.

The transition between sedation, deep sedation and anaesthesia is not an all or none phenomenon. Complications associated with failure to observe this transition, or failing to rescue a patient who has been observed to make this transition are not uncommon.

Historically 50% of all reported complications associated with gastrointestinal endoscopy were cardiopulmonary. The majority of these were aspiration of stomach contents into the lungs, which may give rise to acid-aspiration syndrome or pneumonia. Over sedation with inadequate breathing or obstructed airway closely followed. Finally in response to manipulation of the gut, vaso-vagal reflexes may be stimulated, producing low blood pressure and a dangerously slow heart including transient periods where there is no circulation.16,17,18The incidence of all cardiopulmonary complications was found in one study to be as high as 5.4 per 1000 patients.19

These figures are unacceptable by current standards and reflected the developmental infancy of these procedures. Contemporary standards in most countries seek to avert these unnecessary risks.20 In the USA, for example, the American Gastroenterological Association (AGA) publishes clear guidelines and set immutable standards which reputable clinicians and clinics are expected conform to. These were written in response to market changes in physician reimbursements for many endoscopic procedures that have and, will continue to, drive their performance into unregulated physician offices.21

The AGA believes that patient safety is best protected if sites where these procedures are performed adopt these evidence or consensus-based standards. They emphasise that these sites should also comply with state/federal laws for licensure or are certified as an ASC and/or are accredited by a nationally recognized accreditation program (e.g., the Joint Commission on Accreditation of Healthcare Organization’s [JCAHO] new Office-Based Surgery Standards).22 Evidence of accreditation should be made available when a patient requests it.

Regulation of office based Anaesthesia (USA)

As previously mentioned financial, remunerative and economic considerations have resulted in an increase in the number of procedures performed in office-based environments. Inevitably, legislators have been asked to intervene or have reacted to events by legislating to improve patient safety. Mostly this is undertaken in collaboration with responsible medical organisations.23

Even with statuary legislation (“Laws of New York”24,25), quality and standards of care may be impaired. Despite an increase in medical malpractice suites associated with conscious sedation it remains unclear who can and cannot legally administer these drugs for this intended purpose in which state. In the USA some of the issues revolve around a “turf war” that stems in part from the relative expense of employing a nurse or physician anaesthetists and who is required to provide supervision or oversight.26 It is inappropriate for patients to be caught up in these contentious issues. At all times the patients best interests must be at the forefront of everyone’s minds.

Any patient intending to take advantage of the relative costs and convenience of office based procedure would be well advised to confirm with the intended facility that they conform to local legal standards. An example of standards is published by the Department of Health for New York City.27 In their article “Office-Based Surgery (OBS) Frequently Asked Questions (FAQ’s) for Practitioners” they pose questions that patients may equip themselves with, such as:

    • 1.What are the Office-Based Surgery (OBS) laws and where can I find copies?
    • 2.When did the laws regarding Office Based Surgery become effective?
    • 3.What is Office-Based Surgery?
    • 4.Can you give examples of procedures that are within the definition of OBS?
    • 5.Are there any limits on the types or complexity of procedures that can be performed in an office-based surgery setting? and many more.
In addition, the State Education Department has issued Office-based Surgery and Conscious Sedation guidelines that apply to podiatrists. These can be found at: and

Accreditation, necessary to comply with these legal requirements, is performed by various organisations. For example Accrediting Agencies used by the New York Commissioner may be contacted at the following locations:

American Association for Accreditation of Ambulatory Surgery Facilities (AAAASF)
5101 Washington Street, Suite 2F
Gurnee, IL 60031

Accreditation Association for Ambulatory Health Care (AAAHC)
5250 Old Orchard Road, Suite 200
Skokie, IL 60077

The Joint Commission
One Renaissance Boulevard
Oakbrook Terrace, IL 60181

Similar organisations in different States and countries will perform the same roles. Patients may find it salutary, informative or reassuring to determine if the facilities they intend to use conform to local advisory standards and legal requirements. The ethics of utilising facilities that take advantage of the opacity of legislation in attempts to contain costs but put patients at increased risk are not complicated.


© 2018 POND Awareness

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