Wayne R. Cohen

Catastrophic complications of previous cesarean section

Of 711 patients who were delivered after one or more previous cesarean sections, 17 (2.4%) had an extremely serious complication. Uterine rupture and placenta previa or placenta accreta with accompanying hemorrhage were the major contributors to mortality and major morbidity. Nine uterine ruptures occurred, including five associated with labor with a low transverse uterine scar and one with an unknown scar (1.4% of trials of labor). There were two cases of placenta previa and five with varying degrees of placenta accreta. The nature and frequency of the observed complications emphasize the potentially serious remote consequences of cesarean section.

Association of episiotomy and delivery position with deepperineal laceration during spontaneous delivery in nulliparous women

Spontaneous deliveries of 241 nulliparous women were analyzed to test the hypothesis that both episiotomy and use of stirrups for delivery of infants were related to the occurrence of third- and fourth-degree perineal lacerations. These deep perineal tears occurred in 0.9% of the women delivered of infants without the use of either episiotomy or stirrups and in 27.9% of the women delivered of infants with both episiotomy and stirrups. Women exposed to episiotomy alone or to stirrups alone had intermediate rates of laceration. There was no independent correlation of laceration with maternal age, 1- and 5-minute Apgar scores, or midwife or physician as delivery attendant. The results suggest that selective use of episiotomy and stirrups can minimize perineal trauma during spontaneous delivery in nulliparous women.

Spontaneous infarction of placental chorioangioma and associated regression of hydrops fetalis

We report a case of a large chorioangioma diagnosed prenatally with concomitant meconium peritonitis and hydrops fetalis in the second trimester. Spontaneous regression of the tumor occurred, associated with some resolution of the fetal hydrops and delivery near term with good neonatal outcome.

Cardiac sympathetic activity during rat pregnancy

The turnover of injected tracer [3H] norepinephrine (NE) was determined in heart and interscapular brown adipose tissue of virgin and 10-day and 20-day pregnant rats. In two experiments fractional [3H]NE turnover in heart was 87% and 92% higher in 20-day pregnant animals compared to virgin controls, but did not differ between 10-day pregnant and control animals. NE turnover in brown adipose tissue did not differ between control and pregnant animals at either gestational age. Twenty-four-hour urinary excretion of NE, epinephrine (E), and dopamine (D) was measured serially in six pregnant rats and compared to virgin controls. NE excretion during pregnancy was significantly higher than the controls and showed a progressive increase during the last third of pregnancy. At term the excretion rate was 2.6-fold greater than that of controls. Excretion of E and D did not differ between pregnant and nonpregnant animals. It is concluded that cardiac sympathetic nervous system activity increases during rat pregnancy. That this change in sympathetic activity is not global is indicated by the finding of unchanged NE turnover in interscapular brown adipose tissue. Urinary excretion data are consistent with increased sympathetic activity during late gestation, with no change in adrenal medullary function.

Local heat and cold application after eastern cottonmouth moccasin (Agkistrodon piscivorus) envenomation in the rat: Effect on tissue injury

We studied the effect of local application of heat or cold on the development of tissue necrosis in envenomated rats. Anesthetized animals had 6 mg/kg venom from Agkistrodon piscivorus injected subcutaneously into the lateral aspect of a hind limb. Heat or cold was applied to the site of envenomation in the experimental groups for 4-6 hr, and the injected area was examined histologically after 24 hr. Neither local treatment, with or without the presence of systemic antivenin, significantly affected the severity of tissue necrosis induced by the venom in comparison to a control group left at ambient temperature.

Sex differences in the adrenal catecholamine response to hypoglycemia in rats

We studied the influence of sex on the adrenal catecholamine response to acute insulin-induced hypoglycemia in Sprague-Dawley rats. Eight male and seven female adult rats were anesthetized with pentobarbital, and a microdialysis probe was placed in the left adrenal. Dialyzed epinephrine and norepinephrine levels were measured by high-performance liquid chromatography during a control period and for 1 hour after insulin administration. The blood glucose level was measured every 15 minutes. The same protocol was applied to 23 adult females at various stages of the estrus cycle. The pattern of blood glucose changes during insulin-induced hypoglycemia was similar in both sexes, but males exhibited a significantly greater increase in epinephrine than females (261% v 52%, P = .001) in the sex-comparison experiment. A similar trend was observed for norepinephrine (73% v 0%, P = .075). The adrenal response in females for both catecholamines was not significantly affected by the estrus cycle phase (P = .989 for epinephrine and P = .424 for norepinephrine). We conclude that sex influences the magnitude of the adrenal catecholamine counterregulatory response to hypoglycemia. Males had a significantly greater increase in epinephrine release than females exposed to the same pattern of hypoglycemia. Female responses to hypoglycemia were not influenced by estrus cyclicity.

Hyperglycemia Suppresses the Adrenal Medullary: Response to Hypoxemia

An in vivo microdialysis technique was used to study adrenal medullary function in 6 euglycemic and 6 hyperglycemic anesthetized Sprague-Dawley rats exposed to hypoxia. After stabilization of an adrenal dialysis probe, dialyzable adrenal epinephrine and norepinephrine were measured in response to 15 min of 7.8% oxygen breathing in both groups. In euglycemic rats, hypoxia increased epinephrine and norepinephrine by 650 and 320% above baseline, respectively. During hyperglycemia, (mean plasma glucose level 30.0 mM) epinephrine and norepinephrine rose only 119 and 104%, respectively. The catecholamine increase in the hyperglycemic rats was significantly attenuated in comparison to euglycemic controls (epinephrine, P = 0.0232; norepinephrine, P = 0.0079). These data demonstrate that acute hyperglycemia has the capacity to suppress the normal adrenal medullary response to hypoxemia.

The Adrenal Secretion of Catecholamines during Systemic Metabolic Acidosis in Fetal Sheep

This study was undertaken to determine whether or not metabolic acidemia per se stimulates catecholamine (CA) secretion from the adrenal medulla in fetal sheep. The potential confounding effect of low O2 content, occasioned by the right shift in the oxyhemoglobin dissociation curve with acidemia, was taken into account in experimental design. Hemodynamic values, blood gases, O2 content, lactate and glucose concentrations and adrenal CA secretion rates and plasma CA levels were studied in fetal sheep at baseline and during control (saline infusion) and acidemic (15 and 30% lactic acid infusion) periods. Experiments were conducted after recovery from preparative operations performed under general anesthesia. Arterial pH did not change with saline infusion. During 15 and 30% lactic acid infusions, pH fell to 7.23 and 7.09, respectively, as lactate concentrations increased 4.7 and 10 times. Arterial PCO2 increased from 50 to 58 torr during 30% lactic acid infusion. Fetal CA secretion and plasma concentrations did not change during saline, or 15 or 30% lactic acid infusions. Moreover, hemodynamic parameters did not indicate increased CA secretion. In conclusion, we found no evidence for stimulation of adrenal CA secretion by metabolic acidosis.