Anaesthesia for endoscopy and laser surgery

Canadian Journal of Anesthesia/Journal canadien d'anesthésie -     

An introduction to transoesophageal echocardiography: II. clinical applications

Purpose

As progress has been made in the acquisition of cardiac images with transoesophageal echocardiography, the technique has moved from the confines of the cardiology laboratory into the operating room, the intensive care unit, and the emergency department. This has afforded anaesthetists the opportunity to become familiar with, and develop expertise in its practice. The purpose of this article is to present a review of transoesophageal echocardiography with reference to anaesthetic practice.

Source

The principle source of material was a computerized Medline? search of the English language literature from 1986 to 1995.

Principle findings

After discussing the technique of probe insertion, and describing some of the standard images, transoesophageal echocardiography’s clinical utility is critically assessed. Comparisons with available monitoring techniques are made with reference to ventricular function, valvular heart disease, pericardial, aortic and congenital heart disease, and the management of the multiple traumatized patient. Issues of certification and maintenance of competence are also discussed.

Conclusion

Although the benefit of transoesophageal echocardiography is intuitive in many clinical situations, in others, it has not been shown to improve upon presently existing monitoring techniques. The need for adequate training and collaboration with cardiology colleagues is emphasized.     

A comparison of propofol and thiopentone as induction agents in outpatient surgery

We studied 90 healthy ASA physical status I or II female patients scheduled for outpatient therapeutic abortions. Sixty patients received induction doses of propofol (2.5 mg X kg-1) and 30 patients received thiopentone (4 mg X kg-1). Anaesthesia was maintained with nitrous oxide plus additional doses of the agent used for induction. Comparisons were made regarding the efficacy of induction and maintenance, rapidity of recovery, haemodynamic and respiratory variables and side effects. The number of "excellent" inductions was significantly different (p = 0.02), with 97 per cent of the patients induced with propofol and 80 per cent of the patients induced with thiopentone receiving this rating. A larger number of patients receiving propofol exhibited minor extraneous muscular movement during induction (p = 0.01). Recovery for the propofol group was significantly more rapid than with the thiopentone group (p = 0.001). The respiratory effect of the two drugs was not significantly different. Propofol caused a decrease in pulse rate and a decrease in systolic, diastolic and mean pressure which were significantly greater than with thiopentone. From the observations made we conclude that propofol has the potential to be an excellent induction and maintenance agent for outpatient surgery in combination with nitrous oxide alone.     

A clinical and microbiological study of venous catheterization

In a prospective study of 210 intravenous catheters and needles 31 (15%) swabs yielded 34 microbial isolates. Twenty-eight were “non-pathogenic” skin commensals and six were “pathogenic” organisms. Commensals were isolated predominantly from catheters left in situ for only a short time (up to two days) and pathogenic organisms most frequently from specimens left in situ for a longer time. Correlation was not confirmed between colonization and infection, antibiotic therapy or phlebitis. All samples of IV fluids were sterile on culture. Changing the IV catheter at least every two days is recommended.     

Inhaled nitric oxide does not alter pulmonary or cardiac effects of fat embolism in dogs after cemented arthroplasty

PURPOSE: We examined the effect of inhaled nitric oxide (NO) on the acute pulmonary hypertension and right ventricular (RV) dilation after fat embolism. METHODS: A bilateral cemented arthroplasty (BCA), created fat embolism in 20 dogs. In Part A, 12 dogs were randomized to an NO group (n=6, inhaled NO 40 ppm before BCA and throughout the study) or a control group (n=6). In Part B, a third group of dogs (n=8) were given NO 20-40 ppm 2-3 min after BCA when pulmonary artery pressure (PAP) increased. Transesophageal echocardiography (TEE) and invasive hemodynamic monitoring evaluated the hemodynamic response to BCA. Postmortem, quantitative morphometry was used to estimate the number of fat emboli and diameter of lung vessel occluded by fat. RESULTS: Part A: The increase in PAP in the NO group (16 +/- 1 to 34 +/- 9 mmHg) within three minutes of BCA was not different from that in the control group (14 +/- 4 to 35 +/- 9 mmHg). Within three minutes of BCA, TEE demonstrated RV dilation in all groups (P < 0.05) but there was no difference in the change in RV area in the NO and control groups. When NO was given after BCA, no difference in PAP or RV dilation was noted from that in the control group. There were no differences, at post mortem, between the groups in the diameter of lung vessel occluded by fat CONCLUSION: Whether given before the embolic insult or two to three minutes after the onset of pulmonary hypertension, inhaled NO did not attenuate the acute pulmonary hypertension or RV dilation after cemented arthroplasty.