G. M. Hall

Peri-operative steroid supplementation

‘The need for patients on long-term steroid treatment to increase their dose of glucocorticoids when under stress is a principle that rests in one of the most tranquil corners of medical dogma’ [1]. Two case reports published in the early 1950s described cardiovascular collapse and death in young patients undergoing routine orthopaedic surgery. A 34-year-old man died after the withdrawal of steroids (25 mg cortisone bd) 48 h pre-operatively. Although the case was complicated by possible transfusion reactions and pre-existing cardiomegaly, the cause of death was ascribed to acute adrenal insufficiency precipitated by withdrawal of steroid therapy [2]. The second patient was a 20-year-old woman who had taken 62.5–100 mg cortisone daily for 4 months; she became hyperpyrexic and died less than 6 h after surgery [3]. Autopsy findings revealed gross bilateral adrenal haemorrhage and histological changes of complete, adrenal cortical atrophy. These reports are considered the initial clinical recognition of iatrogenic adrenal insufficiency resulting from exogenous glucocorticoid administration. Subsequently, it has been assumed that the administration of steroids to patients frequently results in suppression and atrophy of the hypothalamic–pituitary–adrenal (HPA) axis through feedback inhibition of both hypothalamic and pituitary function. Adrenocorticotrophic hormone (ACTH) is necessary for normal adrenal gland growth and function and, in its absence, the adrenal glands become atrophic and unable to respond during periods of stress by secreting glucocorticoids. Further studies supported the contention that patients with suppression of the HPA axis required significant glucocorticoid supplementation during physiological stress. However, many of the case reports lacked conclusive biochemical evidence of adrenal insufficiency and Cope pointed out that ‘the vast majority of such incidents seem to be associated with medical diagnostic and not adrenal failure’ [4]. Nevertheless, the case report in 1953 concluded with a list of recommendations for peri-operative glucocorticoid treatment, which have become standard practice [3]. These recommendations amount to approximately a four-fold increase in the dose of glucocorticoid and there now appears to be an ingrained consensus that patients, currently or recently taking exogenous steroids, require additional large doses of steroids when subjected to surgery. Excessive, or prolonged, glucocorticoid administration can result in adverse clinical sequelae, including immunosuppression, delayed wound healing, decreased glucose tolerance, fluid and electrolyte imbalance and psychological effects. In two influential studies in 1969, Plumpton, Besser and Cole attempted to clarify the issue of steroid cover in a prospective study of 100 patients undergoing surgery who had either never received steroids (40 patients), recently stopped taking steroids (40 patients) or who were currently still receiving steroids (20 patients) [5]. Of the 20 patients currently receiving long-term steroid therapy, 10 patients were receiving replacement therapy for Addison’s disease, hypopituitarism or following adrenalectomy and the remaining 10 patients were receiving immunosuppressive therapy for unspecified conditions [6]. The patients treated previously had received prednisolone, or equivalent, in doses ranging from 5 to 50 mg.day for between 6 days and 10 years; the interval since treatment varied from 3 days to 24 months. The patients currently receiving treatment had taken prednisolone, or equivalent, in doses ranging from 5 to 50 mg.day for between 8 days and 15 years [5]. The first two groups of patients did not receive any peri-operative steroids. Steroid-treated patients were assessed pre-operatively using an insulin tolerance test; Anaesthesia, 1998, 53, pages 1091–1104

SHORT-TERM RECOVERY FROM HIP AND KNEE ARTHROPLASTY

There are many studies of long-term recovery from major point arthroplasty, but little is known about the first days and weeks after operation. We measured function, emotional state and life evaluation before arthroplasty and at seven and 50 days after in a consecutive series of 40 hip and 23 knee replacements. Pain was relieved significantly at seven days after hip arthroplasty and even more at 50 days. In knee patients, pain relief was modest and was not apparent until 50 days. Functional ability was much improved by 50 days in hip patients, but hardly changed in knee patients. Positive mood and life satisfaction did not improve in either group. Our findings will help with more accurate information for patients before operation and also in judging the rate of recovery.

Thoracic epidural analgesia started after cardiopulmonary bypass. Adrenergic, cardiovascular and respiratory sequelae.

The effects of thoracic epidural analgesia started after cardiopulmonary bypass were studied on the subsequent adrenergic, cardiovascular and respiratory responses. Sixteen cardiac surgical patients received either a standardised general anaesthetic (control group) or a standardised general anaesthetic and thoracic epidural analgesia (epidural group). The epidural catheter was sited before surgery and heparinisation. Following discontinuation of cardiopulmonary bypass, patients in the epidural group were given 15 ml bupivacaine 0.5% down the catheter followed by an infusion of bupivacaine 0.375% at 5–8 ml.h−1 after surgery. The control group received an intravenous morphine infusion on completion of surgery. The adrenergic response was assessed by measuring arterial catecholamine concentrations. Respiratory function was determined by spirometry, peak expiratory flow and arterial partial pressure of oxygen while breathing air. Pain scores were also obtained. After cardiopulmonary bypass the increases in catecholamine concentrations were effectively inhibited in the epidural group for the remainder of the study (p < 0.05). Postoperative respiratory function was less impaired in the epidural group, with higher forced expiratory volume in 1 s, forced vital capacity and peak expiratory flow (p < 0.05). Pain scores were also significantly lower in the epidural group (p < 0.05). There were no significant differences in cardiovascular parameters.

Growth hormone responses to treadmill sprinting in sprint- and endurance-trained athletes.

The purpose of the present study was to examine the growth hormone (GH) response to treadmill sprinting in male (M) and female (F) sprint- and endurance-trained atheletes. A group of 11 sprint-trained (ST; 6M, 5F) and 12 endurance-trained (ET; 6M, 6F) athletes performed a maximal 30-s sprint on a nonmotorized treadmill. Peak power and mean power expressed in watts or in watts per kilogram body mass were higher in ST than in ET (P < 0.01) and in the men compared to the women (P < 0.01). Serum GH was greater in ST than in ET athletes, but was not statistically significantly different between the men and the women [mean peak GH: ST 72.4 (SEM 12.5) compared to ET 26.3 (SEM 4.9) mU · I−1, P < 0.01; men 59.8 (SEM 13.3) compared to the women 35.8 (SEM 7.4) mU · l−1, n.s.]. Plasma ammonia and blood lactate concentrations were higher and blood pH lower during 1 h of recovery after the sprint in ST compared to ET (all P < 0.01). Multiple log linear regression showed that 82% of the variation in the serum peak GH response was explained by the peak power output and peak blood lactate response to the sprint. As serum GH was still approximately ten times the basal value in ST athletes after 1 h of recovery, it is suggested that the exercise-induced increase in GH could have important physiological effects in this group of athletes, including increased protein synthesis and sparing of protein degradation leading to maintained or increased muscle mass.

Anaesthesia in elderly patients with neurodegenerative disorders: special considerations.

Neurodegenerative diseases are increasingly common in elderly patients, who present a particular anaesthetic challenge. The majority of people over the age of 70 years have some degree of cerebral atrophy. The pathogenesis of neurodegenerative diseases is due to alterations in the transport, degradation and aggregation of proteins. Alterations in physiology that occur with advancing age affect both the pharmacokinetics and pharmacodynamics of drugs used in the elderly. Changes in pharmacokinetics result in either increased or reduced drug concentrations depending on the variable contributions of absorption, metabolism and elimination. The distribution of a drug depends on its protein binding, cardiac output and blood volume, which are all altered in the elderly. Metabolism and excretion of drugs are also affected due to changes in hepatic and renal mass and blood flow in the elderly.A number of drugs are used in neurodegenerative disorders including antidepressants, benzodiazepines, antipsychotics, acetylcholinesterase inhibitors and levodopa. Polypharmacy is a common problem, which can lead to adverse drug interactions and an exacerbation of dementia. Levodopa, bromocriptine and tricyclic antidepressants are known to cause orthostatic hypotension in patients with neurodegenerative disease. Elderly patients are liable to excessive sedation from benzodiazepines in both the pre- and postoperative period; therefore these drugs should be prescribed in low doses. For induction of general anaesthesia propofol is a suitable agent in patients with neurodegenerative disease due to its rapid metabolism, but may not be suitable in patients with Parkinson’s disease as it can induce spontaneous involuntary movements. Volatile inhalational agents should be administered carefully in the elderly, as they are more sensitive to the depressant cerebral and cardiovascular effects. Levodopa should be avoided in conjunction with halothane, which sensitises the heart to catecholamines. Co-administration of monoamine oxidase inhibitors and opioids should be avoided as it can cause agitation, muscular rigidity, sweating and hyperpyrexia. If an anticholinergic agent is required, then glycopyrronium bromide is the drug of choice in this group of patients, as it does not cross the blood brain barrier.Patients should continue to take their usual medications in hospital and do not let the change in routine alter the times at which treatments are administered. This is particularly relevant to the timing of levodopa in Parkinson’s disease, as missed treatment can be detrimental. Regional anaesthesia may, however, have significant advantages in patients with Parkinson’s disease, who can continue to take oral levodopa preoperatively, during surgery, if required, and early in the postoperative period. Anti-emetic drugs such as phenothiazines, butyrophenones and metoclopramide should be used carefully in the postoperative period in these patients as their antidopaminergic effects may induce or exacerbate parkinsonian effects.

Why do patients feel positive about patient-controlled analgesia?

We studied 200 patients to identify the aspects of their experience of patient‐controlled analgesia (PCA) that made them feel ‘extremely positive’ about this technique. After PCA had been withdrawn, patients completed a questionnaire which included the following topics: pre‐operative information, pain relief, the degree of control that PCA afforded the patient, side‐effects and safety. Multiple regression analysis identified three factors of their experience which were associated uniquely with feeling ‘extremely positive’ about PCA: having better pain relief, not worrying about ‘giving oneself too much drug’ and not experiencing feeling ‘peculiar in the head’. Control over pain relief, although highly correlated with feeling ‘extremely positive’ about PCA, was unimportant when these variables were controlled. Because of the well‐recognised difficulties in measuring satisfaction with analgesic regimens, we suggest that a satisfaction score based on these variables would be a significant advance on existing methods.

A Theory of Postoperative Fatigue: An Interaction of Biological, Psychological, and Social Processes

The concept of postoperative fatigue has been developed to explain the feelings of malaise and the reduction in activity during the convalescent period that follows surgery in humans. Fatigue has been assumed to reflect the degree of surgical trauma and to be a consequence of muscle weakness caused by physiological sequelae of the trauma. The evidence is inconsistent with this reductionist view. Instead we propose a theory that postoperative fatigue is based on an emotional and motivational change that has the function of ensuring inactivity so as to preserve homeostasis in vital systems in response to injury while preserving the physical capacity to respond to new challenge. This response, triggered by the patients perception of the surgical stimulus, is prolonged by the influence of staff and patient expectations, which, in turn, reflect cultural beliefs in the necessity of convalescence. This theory can be tested by manipulation of clinical practice at pharmacological and psychological levels.

Diabetes mellitus: anaesthetic management.

As the incidence of diabetes mellitus continues to increase in the United Kingdom, more diabetic patients will present for both elective and emergency surgery. Whilst the underlying pathophysiology of type 1 and type 2 diabetes differs, there is much good evidence that controlling the blood glucose to > 10 mmol.l−1 in the peri‐operative period for both types of diabetic patients improves outcome. This should be achieved with a glucose–insulin–potassium regimen in all type 1 diabetics and in type 2 diabetics undergoing moderate or major surgical procedures. After surgery, a decrease in the catabolic hormone response resulting from good analgesia and the avoidance of nausea and vomiting should allow early re‐establishment of normal glycaemic control.

Fentanyl and the interleukin-6 response to surgery

It has been suggested that large doses of opioids may suppress the interleukin‐6 response to surgery. We examined the effects of the supplementation of inhalational anaesthesia with either 3 or 15 μg.kg−1 fentanyl on the circulating interleukin‐6, interleukin‐8, C‐reactive protein, cortisol and glucose concentrations in 16 patients undergoing pelvic surgery. In both groups, surgery evoked the expected glucose, cortisol and interleukin‐6 response but no increase in interleukin‐8 was detected. There were no significant differences between the two groups. We conclude that the supplementation of inhalational anaesthesia with conventional doses of opioids does not modify the cytokine response to surgery.

Brief review: Angiotensin converting enzyme inhibitors and angioedema: anesthetic implications

PurposeAngiotensin converting enzyme inhibitors (ACEIs) are a group of drugs used to treat hypertension and heart failure, with additional benefits, such as cardiovascular and renal protection, in patients with diabetes. However, angioedema as a complication of ACEI therapy is under-recognized. As there are important implications for anesthesiologists and emergency medicine physicians, a review was undertaken to document the scope of the problem of ACEI-induced angioedema.MethodsA review of the published literature (identified by searching Medline, EMBASE and CINAHL) was undertaken, addressing the clinical uses of ACEIs and the incidence, risk factors, pathophysiology, clinical presentation and management of angioedema associated with the use of these drugs.Principal findingsThe incidence of ACEI related angioedema has increased from 0.1-0.2% to 1% over the last decade. Patients who are receiving ACEIs are predisposed to developing angioedema which may be triggered by trauma, airway instrumentation, infection, and irritant fumes, particularly in those who are at increased risk. Cases of acute facial and airway oedema, due to ACEI drug administration, may be misdiagnosed as an anaphylactic reaction, and the association with ACEIs may be ignored. Some cases of intraoperative and postoperative airway edema may be precipitated by airway instrumentation in patients receiving ACEI drugs. The severity of airway compromise ranges from mild facial edema to severe laryngeal or subglottic edema which may prove life-threatening.ConclusionIn view of the widespread clinical indications and ever-increasing use of ACEI drugs, the potentially life-threatening adverse reaction of ACEI-associated angioedema, and its treatment, must be recognized by anesthesiologists and all clinicians involved in airway management.RésuméObjectifLes inhibiteurs de l’enzyme de conversion de l’angiotensine (IECA) sont utilisés contre l’hypertension et l’insuffisance cardiaque et aussi pour la protection cardiovasculaire et rénale, chez les patients diabétiques. L’œdème de Quincke est toutefois peu connu comme complication de l’usage des IECA. Cette situation ayant des répercussions sur le travail des anesthésiologistes et des urgentistes, une revue a été réalisée pour montrer l’étendue du problème de l’œdème de Quincke induit par l’IECA.MéthodeUne revue des articles publiés (découverts dans Medline, EMBASE et CINAHL) a été faite en abordant les usages cliniques des IECA, l’incidence, les facteurs de risque, la physiopathologie, la présentation et le traitement cliniques de l’œdème de Quincke associés à ces médicaments.Constatations principalesL’incidence d’œdème de Quincke relié aux IECA est passée 0,1–0,2% à 1 % pendant la dernière décennie. Les patients qui prennent des IECA sont prédisposés à l’œdème de Quincke qui peut être déclenché par un traumatisme, une exploration instrumentale, une infection et des émanations irritantes, surtout chez ceux qui sont à haut risque. L’œdème aigu du visage et des voies aériennes peut être diagnostiqué à tort comme une réaction anaphylactique et l’association avec les IECA restée inconnue. L’œdème peropératoire et postopératoire des voies aériennes peut dépendre de l’utilisation d’instruments dans les voies aériennes. La sévérité de l’atteinte peut être un léger œdème facial jusqu’à un œdème laryngé ou sous-glottique important et même très grave.ConclusionDans l’optique des indications cliniques largement répandues, et en augmentation constante, de l’usage des IECA, la réaction indésirable et possiblement grave qu’est l’œdème de Quincke, et son traitement, doivent être connus des anesthésiologistes et de tous les cliniciens concernés par le contrôle des voies aériennes.