Patricia F. Norman

Laparoscopic surgery during pregnancy

BACKGROUND Animal studies have demonstrated fetal acidosis during carbon dioxide pneumoperitoneum. This finding suggests a potential adverse effect of CO2 pneumoperitoneum on fetal outcome in humans. PATIENTS AND METHODS We reviewed our recent experience with laparoscopic surgery performed under general anesthesia and with the use of CO2 pneumoperitoneum, in pregnant women with appendicitis or cholecystitis. We compared these womens charts and pregnancy outcomes with those of pregnant women who underwent formal laparotomy during the same period of time. RESULTS Seven pregnant patients underwent laparoscopic surgery, and there were 4 fetal deaths among them (3 during the first postoperative week, and another 4 weeks postoperatively). Five pregnant patients underwent formal laparotomy, of whom 4 subsequently progressed to term and 1 was lost to follow-up. CONCLUSIONS Our recent experiences together with the available animal data suggest that caution should be used when considering nonobstetrical laparoscopic surgery in pregnant women. This experience suggests that additional clinical and laboratory investigations may be indicated to evaluate fetal risk associated with such surgery.

Nulliparous active labor, epidural analgesia, and cesarean delivery for dystocia.

OBJECTIVE Our purpose was to examine the effect of epidural analgesia on dystocia-related cesarean delivery in actively laboring nulliparous women. STUDY DESIGN Active labor was confirmed in nulliparous women by uterine contractions, cervical dilatation of 4 cm, effacement of 80%, and fetopelvic engagement. Patients were randomized to one of two groups: epidural analgesia or narcotics. A strict protocol for labor management was in place. Patients recorded the level of pain at randomization and at hourly intervals on a visual analog scale. Elective outlet operative vaginal delivery was permitted. RESULTS One hundred women were randomized. No difference in the rate of cesarean delivery for dystocia was noted between the groups (epidural 8%, narcotic 6%; p = 0.71). No significant differences were noted in the lengths of the first (p = 0.54) or second (p = 0.55) stages of labor or in any other time variable. Women with epidural analgesia underwent operative vaginal delivery more frequently (p = 0.004). Pain scores were equivalent at randomization, but large differences existed at each hour thereafter. The number of patients randomized did not achieve prestudy estimates. A planned interim analysis of the results demonstrated that we were unlikely to find a statistically significant difference in cesarean delivery rates in a trial of reasonable duration. CONCLUSIONS With strict criteria for the diagnosis of labor and with use of a rigid protocol for labor management, there was no increase in dystocia-related cesarean delivery with epidural analgesia.

Prophylactic Angiotensin II infusion during spinal anesthesia for elective cesarean delivery

Background Angiotensin II may prove useful in treating regional anesthesia‐induced hypotension in obstetric patients, because it causes less uterine vasoconstriction than do other vasoconstrictor drugs (such as phenylephrine). This study compared (1) maternal blood pressure and heart rate and (2) fetal status at delivery in parturients given either prophylactic angiotensin II or ephedrine infusion during spinal anesthesia for elective cesarean delivery. Methods Fifty‐four women were randomized to receive either angiotensin II or ephedrine infusion intravenously during spinal anesthesia for elective cesarean section delivery. Simultaneous with subarachnoid injection, infusion of angiotensin II (2.5 [micro sign]g/ml) or ephedrine (5 mg/ml) was initiated at 10 ng [middle dot] kg‐1 [middle dot] min‐1 and 50 [micro sign]g [middle dot] kg‐1 [middle dot] min‐1, respectively. The rate of each infusion was adjusted to maintain maternal systolic blood pressure at 90–100% of baseline. Results Cumulative vasopressor doses (mean +/‐ SD) through 10, 20, and 30 min were 150 +/‐ 100, 310 +/‐ 180, and 500 +/‐ 320 ng/kg in the angiotensin group and 480 +/‐ 210, 660 +/‐ 390, and 790 +/‐ 640 [micro sign]g/kg in the ephedrine group. Maternal heart rate was significantly higher (P < 0.001) during vasopressor infusion in the ephedrine group than in the angiotensin group. Umbilical arterial and venous blood pH and base excess were all significantly higher (P < 0.05) in the angiotensin group than in the ephedrine group. Conclusions Angiotensin II infusion maintained maternal systolic blood pressure during spinal anesthesia without increasing maternal heart rate or causing fetal acidosis.

The Minimum Alveolar Concentration of Isoflurane in Patients Undergoing Bilateral Tubal Ligation in the Postpartum Period

Background The minimum alveolar concentration (MAC) of volatile anesthetics is decreased during pregnancy, but MAC in the early postpartum period has not been reported. The aim of this study was to determine the MAC of isoflurane and to evaluate the relation between MAC and serum progesterone and beta-endorphin in patients after delivery. Methods Eight patients undergoing elective bilateral tubal ligation during general anesthesia in the early postpartum period (< 12 h postpartum) and eight patients undergoing this procedure in the late postpartum period (12-25 h postpartum) were studied. Eight patients undergoing bilateral tubal ligation more than 6 weeks after delivery served as control subjects. Anesthesia was induced with propofol and maintained with isoflurane in oxygen to a steady end-tidal concentration of 0.8-1.0 vol% for 10 min. Reaction to a standardized electric stimulation applied to the forearm was graded as positive (gross or delayed movement) or negative. By using the bracketing technique, the concentration of isoflurane was increased or decreased by 0.1 vol%, depending on the positive or negative responses. Results The MAC (mean plus/minus SD) in patients in the early postpartum period was significantly less (0.75 plus/minus 0.17 vol%) than that in control subjects (1.04 plus/minus 0.12 vol%; P < 0.01) and that in patients in the late postpartum period (0.95 plus/minus 0.2 vol%; P < 0.05). The difference in MAC values between late postpartum and control was not significant (P > 0.05). There was an inverse correlation between progesterone concentration postpartum and time after delivery (r = -0.527; P = 0.036), but no relation between beta-endorphin and time after delivery (r = 0.089; P = 0.744). There was no correlation between plasma progesterone or beta-endorphin and MAC by multiple regression (r = 0.166; P = 0.950). Conclusions Isoflurane MAC remains 28% less than normal within the 1st 12 h postpartum and then returns to normal 12-25 h after delivery.