Cardiac complications and mortality rates in diabetic patients following non-cardiac surgery in an Australian teaching hospital.

This retrospective study of diabetic patients undergoing non-cardiac surgery has identified that a greater number of patients are at risk of cardiac complications and death in the perioperative period than had previously been suggested. As well as insulin-dependent diabetic patients and patients with elevated creatinine (> 178 micromol/l) as previously found, our study suggests that non-insulin-dependent diabetic patients and patients with creatinine > 120 micromol/l are also at increased risk of cardiac complications and death following non-cardiac surgery. This increases by a factor of six those diabetic patients at risk of perioperative complications from non-cardiac surgery and also increases the number of patients with renal failure similarly at risk. The study confirms similar risks of cardiac complications and death to other recently published data and suggests ongoing comparisons will contribute to quality assurance activities in anaesthesia and surgery.

Perioperative complications in patients with drug-eluting stents: a three-year audit at Geelong Hospital.

Drug-eluting stents are a recommended treatment for lesions in the coronary arteries. Stent insertion requires the patient remain on anti-platelet medication for a minimum of six months after insertion. A serious consequence of ceasing anti-platelet medication is late stent thrombosis leading to myocardial infarction in the territory of the drug-eluting stent. Continuing anti-platelet medication can lead to excessive bleeding at the time of surgery. Understanding the risk of complications attributable to bleeding or myocardial ischaemia will help in defining the optimal management of these patients at the time of non-cardiac surgery. This study is a retrospective database analysis and case note review of all patients with drug-eluting stents presenting for non-cardiac surgical procedures over a three-year period in one centre. Twenty-four patients with drug-eluting stents inserted presented for 43 non-cardiac surgical procedures. Severe bleeding problems were encountered in one case. Three of 15 patients (20%) who ceased clopidogrel prior to surgery without alternative anti-thrombotic prophylaxis suffered myocardial infarction due to stent thrombosis. Four patients who received alternative anti-thrombotic prophylaxis did not suffer complications. All 19 patients who ceased clopidogrel remained on aspirin prior to surgery. Patients treated with drug-eluting stents for coronary artery stenosis represent a challenging group of patients for subsequent perioperative management. The risk of myocardial infarction when clopidogrel is stopped prior to surgery is 20%, if alternative anti-thrombotic prophylaxis is not used. This risk persists beyond one year after insertion of drug-eluting stents. Some treatments appear to be effective in reducing the risk of myocardial infarction.

Fiduciary disclosure of medical mistakes: the duty to promptly notify patients of adverse health care events.

Fiduciary obligations are imposed by the common law to ensure that a person occupying a societal role with a high potential for the manipulation of vulnerable persons exercises utmost good faith. Australian law has recognised that the doctor-patient relationship, while not wholly fiduciary, has fiduciary aspects. Amongst such duties are those prohibiting sexual or financial abuse of patients or disclosure without express authority of confidential information. One important consequence of attaching such fiduciary duties to the doctor-patient relationship is that the onus of proof falls not upon the vulnerable party (the patient), but upon the doctor (to disprove the allegation). Another is that consent cannot be pleaded as an absolute defence. In this article the authors advocate that the law should now accept that the fiduciary obligations of the doctor-patient relationship extend to creating a legal duty that any adverse health care event be promptly reported to the patient involved. The reasons for creating such a presumption, as well as its elements and exceptions, are explained.

Unusual cause of intraoperative hypotension diagnosed with transoesophageal echocardiography in a patient with renal cell carcinoma.

Transoesophageal echocardiography (TOE) is not commonly used in the management of non-cardiac cases. We report a case where the use of TOE played a major role in the intraoperative diagnosis and subsequent management of a patient exhibiting severe hypotension whilst undergoing a nephrectomy. The rare diagnosis of a secondary intraventricular tumour would not have been evident with more conventional monitoring techniques.

Effect of i.v. furosemide on pelvic urinary oxygen tension in humans.

Urinary oxygen tension may be an index of renal medullary blood flow. The effect of i.v. furosemide on urinary oxygen tension was studied in four patients with indwelling nephrostomy tubes. An intravascular oxygen sensor (Paratrend 7, Biomedical Sensors Ltd, UK) was inserted into the renal pelvis via the nephrostomy and urine oxygen tension measured. In all cases, furosemide 20 mg i.v. produced a decrease in pelvic urinary oxygen. The possible mechanisms and implications are discussed.

Professional misconduct: the Bristol case.

In June 1998, the Professional Conduct Committee of the General Medical Council of the United Kingdom (the body which regulates British doctors) concluded the longest-running case it has considered this century. Three medical practitioners were accused to serious professional misconduct relating to 29 deaths (and four survivors with brain damage) in 53 paediatric cardiac operations undertaken at the Bristol Royal Infirmary between 1988 and 1995. All three denied the charges but, after 65 days of evidence over eight months (costing 2.2 Pounds million), all were found guilty. The doctors concerned are Mr James Wisheart, a paediatric and adult cardiac surgeon (appointed in 1976, now retired), and the former Medical Director of the United Bristol Healthcare Trust (the hospital group that includes the Bristol Royal Infirmary); Mr Janardan Dhasmana, paediatric and adult cardiac surgeon (appointed in 1986); and Dr John Roylance, a former radiologist, and Chief Executive of the Trust from its creation in 1991 until his retirement in 1995. The central allegations were that the Chief Executive and the Medical Director of the Trust allowed to be carried out, and the two paediatric cardiac surgeons carried out, operations on children knowing that the mortality rates for these operations, in the hands of these surgeons, were high. Furthermore, the surgeons were accused of not communicating to the parents the correct risk of death for these operations in their hands. Stephen Bolsin, a cardiac anaesthetist, "blew the whistle" and then had the courage to follow through until a full investigation was carried out. The process took over six years. Here he tells his story.

Effect of dopexamine hydrochloride on renal vascular resistance index and haemodynamic responses following coronary artery bypass graft surgery.

A randomized double-blind study was carried out on 20 patients after coronary artery bypass surgery to investigate the effects of graded doses of dopexamine hydrochloride or placebo on systemic haemodynamic responses and renal vascular resistance index (RVRI) measured using Doppler ultrasound. Pre-operatively, all patients had good left ventricular function and normal renal function. Eleven were allocated randomly to receive incremental infusions of dopexamine 0.5, 1, 2, and 4 micrograms kg-1 min-1 for 40 min each, and nine received corresponding infusions of placebo. One patient was withdrawn from the dopexamine group because of tachycardia. In the remaining 19, heart rate (HR) and cardiac index (CI) were significantly (P < 0.05) increased from base-line with dopexamine: the HR values with dopexamine differed significantly from those with placebo at the 2 and 4 micrograms kg-1 min-1 dose and at 4 micrograms kg-1 min-1 for CI. Systemic vascular resistance index (SVRI) fell significantly in both groups: the reduction was significantly greater with dopexamine 4 micrograms kg-1 min-1 than with the corresponding infusion of placebo. RVRI increased and urine output decreased significantly during the infusions in both groups, but with no significant difference between groups. There were no changes in systemic arterial pressures, pulmonary artery occlusion pressures, stroke volume index or left ventricular stroke work index. Where changes from base-line occurred in either group, they had not returned to base-line within 40 min of stopping the infusions (except perhaps for CI in the dopexamine group). Dopexamine appears to offer no particular protection to the renal vascular bed.

Modification of the diuretic and natriuretic effects of a dopamine infusion by fluid loading in preoperative cardiac surgical patients.

An intravenous infusion of dopamine at 2.5 microgram/kg/min was administered for 40 minutes to anesthetized cardiac surgical patients, and their renal function was measured. Five patients had the usual preoperative regimen of reduced fluid intake for the night and morning before surgery (nonhydrated), and five patients received normal saline, 2 mL/kg/hr intravenously, for 6 hours before anesthesia (hydrated). Renal function (measured by urine output, sodium excretion, free water clearance, and fractional excretion of sodium) was similar immediately before starting the dopamine infusion. All four variables were significantly higher in the hydrated group after 10 minutes; this difference becoming maximal after 40 minutes. Twenty minutes after stopping the dopamine infusion, renal function was similar in the two groups. This study indicates that preoperatively fluid-restricted patients demonstrate powerful salt and water conservation with reduced natriuretic and diuretic responses to a low-dose dopamine infusion when compared with hydrated patients. Patients with adequate fluid loading and intravascular volume will demonstrate a marked natriuresis and diuresis in response to low-dose dopamine infusion.

Total i.v. anaesthesia with propofol and alfentanil for coronary artery bypass grafting.

The haemodynamic effects of total i.v. anaesthesia with a combination of propofol and alfentanil infusions were studied in eight patients with good left ventricular function undergoing coronary artery bypass surgery. Haemodynamic indices were measured before anaesthesia and at specified intervals before cardiopulmonary bypass. The technique resulted in haemodynamic changes comparable to those reported with opioid-based anaesthesia for coronary artery surgery, and has potential advantages.

Anaesthesia for closed embolisation of cerebral arteriovenous malformations.

Cerebral arteriovenous malformation embolisation is a therapeutic, neuroradiological procedure involving injection of bucrylate glue into the nidus of the AV malformation to obliterate the abnormal vascular network. These procedures may involve significant risks, are often long and thereby necessitate the need for some form of sedation and for adequate monitoring of the cerebral, cardiovascular and respiratory systems. The anaesthetic management of a series of twenty patients undergoing embolisation of a cerebral arteriovenous malformation is outlined, seven general and nineteen neurolept anaesthetics being administered. Neurolept anaesthesia is the preferred technique as neurological assessment during the procedure is possible and complications may be diagnosed immediately. Systemic arterial hypotension may facilitate the embolisation process and various agents, including glyceryl trinitrate and sodium nitroprusside, have been employed for this purpose.