H. Higham

Issues in the Perioperative Management of the Elderly Patient with Cardiovascular Disease

The elderly patient may show normal physiological changes of the cardiovascular and respiratory systems that accompany aging, as well as features of intrinsic cardiac disease. The latter include: a past history of myocardial infarction or ischaemic heart disease; history of congestive cardiac failure; angina; arterial hypertension (BP >140/90mm Hg); and conduction disorders. A key aspect to the safe and effective anaesthetic management of the elderly patient with cardiac disease is a careful preoperative assessment and optimisation of pre-existing drug therapies. All cardiac medications should be continued up to and including the morning of surgery with the exception of anticoagulation involving warfarin, and perhaps large doses of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists in patients with hypertension or heart failure.Anaesthetic techniques used in these patients should avoid episodes of excessive hypotension after induction of anaesthesia or large blood loss, or the combination of hypertension and tachycardia after noxious stimulation. The latter physiological disturbances are pivotal for the development of myocardial ischaemia.Both premedication (if used) and anaesthesia should avoid excessive sedation and respiratory depression. The choice of anaesthetic technique may vary between: a balanced technique involving an opiate and a volatile agent; an intravenous technique utilising infusions of propofol; or regional anaesthesia with or without additional sedation. There are no good data to suggest any one technique is better than the rest.The occurrence of ischaemia in the perioperative period may precede the postoperative development of significant cardiac morbidity and mortality (including myocardial infarction or unstable angina, congestive cardiac failure, cerebrovascular accidents, and severe arrhythmias). A number of strategies have been examined to reduce these adverse outcomes. The effect of acute β-adrenoceptor blockade in treatment-naive patients is associated with reduction in the haemo-dynamic response to noxious stimuli and decreased ECG evidence of myocardial ischaemia, as well as a reduction in the number of cardiac adverse events. Other drugs (calcium channel antagonists, α2-agonists and adenosine modulators) have a less predictable influence on both myocardial ischaemia and hard cardiac outcomes. There is inadequate evidence at present to define the optimal time course for acute β-blockade, or the groups of patients in whom preoperative β-blockade should be initiated in the absence of contraindications. Nevertheless, addition of β-blockers to the preoperative regimen should be considered in patients with evidence of or at risk for coronary disease undergoing major surgery. There is also evidence that long-term β-adrenoceptor or calcium channel blockade or nitrate therapy for the high-risk cardiac patient offers little protection against silent myocardial ischaemia, nonfatal infarction, cardiac failure and cardiac death.

Peri-operative troponin I concentration as a marker of long-term postoperative adverse cardiac outcomes - A study in high-risk surgical patients

We have previously demonstrated that the peri‐operative measurement of increased serum concentrations of the cardiac markers troponins I and T and creatine kinase‐MB can be predictors of major cardiovascular outcomes (including cardiac death) at 3 months after surgery. In the present study, we have followed the postoperative course of 157 patients undergoing major vascular surgery or major joint arthroplasty to 1 year using a patient questionnaire, general practitioner follow‐up and case‐notes review. Increased postoperative marker concentrations were defined as values greater than the upper reference limit. Increases in troponin I and troponin T concentrations, as well as a single elevated creatine kinase‐MB and two successively elevated creatine kinase‐MB concentrations were measured in 12, 13, 33 and 15 patients respectively. Thirty‐nine major adverse cardiac outcomes were recorded (cardiac death, myocardial ischaemia, congestive cardiac failure, unstable angina, cerebrovascular accident and major arrhythmias needing active treatment). There was no association between increases in any of these cardiac markers and cardiac death to 1 year. However, increases in troponin I and both a single elevated creatine kinase‐MB and two successively elevated creatine kinase‐MB concentrations were associated with an increased incidence of major cardiac outcomes, including cardiac death, to 1 year (odds ratio [95% confidence intervals] = 4.19 [1.16–14.87], 3.97 [1.65–9.44] and 5.19 [1.60–16.22], respectively).

Peri-operative silent myocardial ischaemia and long-term adverse outcomes in non-cardiac surgical patients.

Two hundred and seventy‐five non‐cardiac surgical patients were recruited to determine risk factors associated with the development of postoperative cardiovascular complications during the first year after surgery. Patients underwent ambulatory electrocardiography pre‐ and postoperatively. There were 34 adverse events over the whole study period. Twenty‐four occurred within 6 months and the remaining 10 occurred between 6 and 12 months postoperatively. Silent myocardial ischaemia was associated with adverse outcome over both the first 6 months [OR 4.44 (95% CI 1.77–11.13)] and the whole study period [OR 2.81 (1.26–6.07)]. Other risk factors were: vascular surgery [OR 17.09 (2.67–351.44)], history of angina [OR 6.29 (2.21–17.62)], concurrent treatment with calcium entry blockers [OR 2.68 (1.03–6.93)] and smoking [OR 4.93 (2.00–12.02)]. None of these was a useful predictor of long‐term outcome (between 6 and 12 months postsurgery). These results are at variance with other published data, but we conclude that monitoring for peri‐operative silent myocardial ischaemia does not aid the prediction of long‐term cardiovascular complications.

Failure to perceive clinical events: An under-recognised source of error ☆

INTRODUCTION Attentional focus narrows as individuals concentrate on tasks. Missing an event that would otherwise appear obvious is termed a perceptual error. These forms of perceptual failure are well-recognised in psychological literature, but little attention has been paid to them in medicine. Cognitive workload and expertise modulate risk, although how these factors interplay in practice is unclear. This video-based experiment was designed to explore the hypothesis that perceptual errors affect clinicians. METHODS 142 volunteers with varying levels of experience of adult resuscitation were shown a short video depicting a simulated cardiac arrest. This video included a series of change-events designed to elicit perceptual errors. The experiment was conducted on-line, with participants watching the video and then responding via combinations of open-ended free-text and directed questioning. RESULTS 141 people experienced at least a single perceptual error. Even the most clinically significant event (disconnection of the patients oxygen supply) was missed by three in four viewers. Although expertise was associated with increased likelihood of detecting an occurrence, even highly significant events were missed by up to two thirds of the most experienced observers. DISCUSSION This study demonstrates, for the first time, that perceptual errors occur during healthcare-relevant scenarios at significant levels. Events such as an oxygen malfunction would meaningfully affect patient outcome and, although expertise conferred some advantages, events were still missed more often than not. Data acquisition is fundamental to good-quality situational awareness. These results suggest perceptual error may be a contributor to adverse events in practice.

Go/no-go decision in anaesthesia: wide variation in risk tolerance amongst anaesthetists

Background. The variability in risk tolerance in medicine is not well understood. Parallels are often drawn between aviation and anaesthesia. The aviation industry is perceived as culturally risk averse, and part of preflight checks involves a decision on whether the flight can operate. This is sometimes termed a go/no‐go decision. This questionnaire study was undertaken to explore the equivalent go/no‐go decision in anaesthesia. We presented anaesthetists with a range of situations in which additional risk might be expected and asked them to decide whether they would proceed with the case. Methods. An electronic questionnaire was distributed to anaesthetic colleagues of all grades in one National Health Service Trust. Eleven scenarios, all drawn from critical incident data, were presented. Participants were invited to consider whether they would proceed, how they would modify their anaesthetic technique, and to predict whether a colleague with similar experience would make the same decision. Textual responses were analysed qualitatively. Results. The scenario response rate was 28%. Consultants were significantly more likely to proceed than trainees. In no scenario was there absolute agreement over whether to proceed, even in scenarios where national guidelines would suggest a case should be cancelled. Thematic analysis suggested a wide variability in what anaesthetists consider acceptable or professional behaviour. Conclusions. It is clear that safety decisions cannot be made in isolation and that clinicians must consider operational requirements, such as throughput, when making a go/no‐go decision. The level of variability in decision‐making was surprising, particularly for scenarios that appeared to go against guidelines.

To err is human: use of simulation to enhance training and patient safety in anaesthesia

Abstract Human beings who work in complex, dynamic, and stressful situations make mistakes. This is as true for anaesthetists as for any other health‐care professional, but we face unique challenges in the many roles and responsibilities we have in diverse clinical contexts. As a profession, we are well versed in the development and utilization of improvement techniques and technologies that prioritize high‐quality, safe care for patients. This article focuses on one particular domain of patient safety in which anaesthetists have been pre‐eminent, the use of simulation in training to improve both professional capabilities and patient safety in anaesthetic practice. This review considers the impact of error in health care; the role of anaesthetists in promoting simulation‐based education for the development of clinical skills and improved teamwork; and their role in disseminating human factors and quality improvement science to enhance safety in the clinical workplace. Finally, we consider our position at the vanguard of developments in patient safety and how the profession should continue to pursue a leadership role in the application of simulation‐based interventions to training and systems design across health care.

Preoperative fast heart rate: a harbinger of perioperative adverse cardiac events

Recent studies have shown that approximately 10% of patients with, or at risk for, cardiovascular disease suffer a major adverse cardiac event (MACE) within 30 days of surgery. In such patients non-invasive and invasive preoperative investigations may reveal conditions needing preoperative treatment. In unselected populations such complications also occur, albeit less frequently, but investigations of the cardiovascular system are seldom, if ever, as extensive as in high risk patients. Could preoperative tachycardia be a valuable signal of increased risk? For many years it has been known that tachycardia is an important causative factor for myocardial ischaemia and myocardial injury, including myocardial infarction, as a result of an imbalance between increased myocardial oxygen demand and reduced oxygen supply caused by the reduced duration of diastole. 5 Tachycardia has been identified as amajor cause of perioperative myocardial infarction for several decades both in daily life and the perioperative period. In prolonged non-cardiac surgery tachycardia and hypertension are independent predictors of adverse outcome. Similarly, in intensive care patients at risk for cardiac complications according to the revised cardiac risk index, prolonged periods of tachycardia are associatedwith adverse cardiac outcome including cardiac death. Myocardial damage, includingmyocardial infarctionmay result from the imbalance between oxygen demand and oxygen supply and also from the adverse effect of a fast heart rate on unstable plaques of atheroma resulting in their disruption and, possibly, coronary occlusion. Epidemiological data from the general population consistently demonstrate that a fast resting heart rate is associated with cardiovascular risk and mortality. 13 The fast heart ratemay be causative in itself, or simply be amarker of an underlying disease such as heart failure. Continuousmonitoring of the ECG in the perioperative period has shown that silent myocardial ischaemia, often caused by tachycardia, is very frequent and is associated with adverse outcome in a variable proportion of patients. 16 As only aweak correlation exists between silent ischaemia and major outcomes in some groups of patients, there has been increasing interest in monitoring troponins as markers of myocardial injury. The adverse prognostic role of elevated troponins was confirmed in a systematic review and meta-analysis of 14 studies with 3381 patients. The VISION study (Vascular Events inNon-cardiac Surgery Patients Cohort Evaluation) enrolled adult patients presenting for surgery (eligible patients were agedmore than 45 yr and required at least an overnight hospital admission after non-cardiac surgery). In this prospective study serial ECGs and serial troponin T measurements were obtained before and for three days after surgery. The aim of the study was to document the risk of cardiovascular adverse events, represented by elevated troponin T, myocardial infarction according to its third universal definition, and mortality, in an essentially unselected population, as opposed to studies in high risk patients. Adverse outcome such as myocardial injury in non-cardiac surgery (MINS) occurred in 7.9% of patients (1197/15 087), myocardial infarction in 2.8% of patients (454/16 007) and 2% of patients died (315/16 037). With extensive data on troponin T, the study showed that even modest increases in troponin T were associated with increased mortality within 30 days of surgery. This led to the development of the concept of MINS defined as prognostically

Simulation training for dental foundation in oral and maxillofacial surgery - a new benchmark.

Simulation training involves reproducing the management of real patients in a risk-free environment. This study aims to assess the use of simulation training in the management of acutely ill patients for those in second year oral and maxillofacial surgery dental foundation training (DF2s). DF2s attended four full day courses on the recognition and treatment of acutely ill patients. These incorporated an acute life-threatening events: recognition and treatment (ALERT™) course, simulations of medical emergencies and case-based discussions on management of surgical inpatients. Pre- and post-course questionnaires were completed by all candidates. A maximum of 11 DF2s attended the course. The questionnaires comprised 1-10 rating scales and Likert scores. All trainees strongly agreed that they would recommend this course to colleagues and all agreed or strongly agreed that it met their learning requirements. All DF2s perceived an improvement in personal limitations, recognition of critical illness, communication, assessing acutely ill patients and initiating treatment. All participants felt their basic resuscitation skills had improved and that they had learned new skills to improve delivery of safety-critical messages. These techniques could be implemented nationwide to address the more complex educational needs for DF2s in secondary care. A new benchmark for simulation training for DF2 has been established.