Steven S. Schwalbe

The use of small-dose intravenous nitroglycerin in a case of uterine inversion

U terine inversion is a rare complication, occurring in 0.04%-0.06% of vaginal deliveries, but one that creates serious risk to the patient (l-3). It is associated with profuse hemorrhage and lifethreatening shock. Relaxation of the uterus may be necessary to facilitate its reinsertion. The anesthesiologist may therefore face the difficult situation of having to provide rapid uterine relaxation, usually with a volatile inhaled anesthetic, in a hypovolemic patient. Nitroglycerin is a vascular smooth muscle relaxant whose actions are mediated by cyclic guanosine 3’,5’monophosphate. Nitroglycerin has been successfully used for uterine relaxation in cases of retained placentas (4,5). We describe a case of uterine inversion in which relaxation of the uterus was accomplished quickly and safely with the use of intravenous nitroglycerin. The dose used was sufficient to relax the uterus but did not result in hypotension (4,5).

Automated blood pressure measurements in laboring women: Are they reliable?

OBJECTIVE In laboring women a consistent difference has become evident between measurements obtained with an automated blood pressure device and those obtained with the auscultatory method. A prospective study was designed to assess the concordance of these two methods. STUDY DESIGN Three sets of brachial blood pressure measurements were made by both oscillatory and auscultatory techniques in 30 women in labor, 20 term pregnant women not in labor, and 20 nonpregnant volunteers. RESULTS In the nonlaboring women and the nonpregnant controls there was satisfactory agreement between the results of the two methods of measurement. In the parturients systolic pressures were consistently and significantly higher and diastolic pressures consistently and significantly lower with the oscillatory compared with the auscultatory method, but mean arterial pressures were not different. CONCLUSION In laboring women there is a discrepancy between systolic and diastolic pressures obtained by the auscultatory versus the oscillatory method of measurement, although mean pressures are not significantly different. We suggest that during labor the diagnoses of hypertension and hypotension be based on the mean rather than the systolic or diastolic pressure.

Hypoglycemia enhances bupivacaine-induced cardiotoxicity in the rat

The effect of blood glucose concentration on bupivacaine-induced cardiotoxicity was investigated in normoglycemic and hypoglycemic adult rats and compared to that of equipotent doses of lidocaine. The anesthetic agents were injected intraperitoneally into tracheostomized animals anesthetized with ketamine. ECG and direct blood pressure measurements were recorded continuously. Femoral arterial blood was used for determinations of glucose level, potassium concentration and base deficit values. Blood was drawn from the heart at the time of death for local anesthetic levels. In hypoglycemic animals, bupivacaine rapidly produced serious dysrhythmias leading to asystole. In normoglycemic rats, only ST-segment changes followed bupivacaine injection and death ensued from hypoxemia secondary to respiratory failure. With lidocaine, both hypoglycemic and normoglycemic rats died of hypoxemia following respiratory paralysis without antecedent dysrhythmias. Thus, hypoglycemia enhanced the cardiac effects of bupivacaine but not those of lidocaine.