Isoflurane and mivacurium chloride neuromuscular blockade in patients with myasthenia gravis.

The relaxograph findings are presented in two patients. In the first, isoflurane alone is administered, and mivacurium with isoflurane is administered to the second patient with myasthenia gravis. A significantly lower dose of mivacurium is required. It was noticed that the T4:T1 ratio was 100% after mivacurium and reversal agent, but T1 did not return to normal. In the patient that only received isoflurane, T1 was 60% to 70% of the baseline, indicating the neuromuscular blocking effects of isoflurane. These cases illustrate that inhalation anesthetics are adequate for muscle relaxant effects, and if neuromuscular blockers are necessary, then a lower dose of nondepolarizer should be administered, and the patient carefully monitored. Mivacurium appears to be an ideal agent for neuromuscular blockade in myasthenia gravis as long as careful neuromuscular blockade is performed.

Dynamic left ventricular outflow tract obstruction. Diagnosis by transesophageal echocardiography in a critically ill patient.

Dynamic left ventricular outflow tract obstruction (DLVOTO) can be present in critically ill patients with congestive heart failure. Diagnosis by transthoracic two-dimensional echocardiography may be technically difficult in the critically ill patient or patients who are obese. This report describes the diagnosis of DLVOTO by transesophageal echocardiography and subsequent management.

Postpneumonectomy pulmonary edema. A retrospective analysis of associated variables.

STUDY OBJECTIVE: Evaluate the correlation between intravenous fluid administration and postpneumonectomy pulmonary edema. DESIGN: Retrospective chart review. SETTING: Large multispecialty group practice hospital. PATIENTS: Adults who had a pneumonectomy performed between 1977 and 1988. MEASUREMENTS AND RESULTS: Patients were identified who had postpneumonectomy pulmonary edema (PPE). Fluid administration and fluid balance information was found in records and compared with age- and sex-matched control patients who did not develop PPE. The side of pneumonectomy was noted for patients in each group. Autopsy findings were recorded for patients who died. Twenty-one patients met PPE criteria. No significant difference was found between groups for fluid administration or fluid balance. Patients who had right pneumonectomy had a significantly higher incidence of PPE. Patients with PPE had a 100 percent mortality rate and histologic evidence of the adult respiratory distress syndrome (ARDS) at autopsy. CONCLUSIONS: PPE is caused by noncardiogenic pulmonary edema rather than excess intravenous fluid administration. There is a greater incidence of the syndrome with right pneumonectomy for unknown reasons. The mortality rate is high despite interventions for ARDS.

Pancuronium, vecuronium, and heart rate during anesthesia for aortocoronary bypass operations.

To determine the effects of pancuronium and vecuronium on heart rate, 90 patients scheduled for aortocoronary bypass were randomly assigned to one of three groups (30 patients each) which received vecuronium 100 micrograms[sdot]kg-1, pancuronium 100 micrograms[sdot]kg-1, or a mixture of vecuronium (50 micrograms[sdot]kg-1) and pancuronium (50 micrograms[dot]kg-1) in a double-blind fashion during induction of anesthesia. All patients were premedicated with lorazepam prior to surgery, hence avoiding the effects of scopolamine. Our results showed no significant increase in heart rate from the administration of pancuronium, following administration of this drug the heart rate increased by only four beats per minute. The heart rate was unchanged after the mixture, but decreased by twelve beats per minute after vecuronium (P < 0.05). The heart rate response differed by 16 beats per minute between pancuronium and vecuronium. All patients who received either of the neuromuscular relaxants and who were on beta blockers showed a decrease in heart rate. In this study, the administration of pancuronium after an adequate induction dose of fentanyl did not cause tachycardia. We therefore feel that pancuronium still has a role in cardiac anesthesia, especially as the newer muscle relaxants such as vecuronium, pipecuronium and doxacurium are significantly more expensive.