Jaya Ramanathan

Correlation between Bleeding Times and Platelet Counts in Women with Preeclampsia Undergoing Cesarean Section

Platelet count and bleeding time and the correlation between these two variables in women with preeclampsia who received epidural or general anesthesia for cesarean section were evaluated. The study included 106 women with preeclampsia who were undergoing cesarean section and 94 healthy, term parturients receiving epidural anesthesia for labor analgesia or for cesarean section. Platelet counts were measured using an automated Coulter Counter, and bleeding times were measured using the modified Ivy bleeding time technique. Platelet count was significantly lower and bleeding time significantly prolonged in patients with preeclampsia compared with the control group (P less than 0.0001). In the preeclampsia group, eight patients (7.5%) had thrombocytopenia (platelet count less than 100,000/mm3), whereas in the control group, all women had a normal platelet count (greater than 150,000/mm3). All but one patient with thrombocytopenia had prolonged bleeding time. In addition, 34% of those women with severe preeclampsia and 13% with mild preeclampsia had prolonged bleeding time, although their platelet count was adequate. In the control group, 2% had abnormal bleeding time in the presence of a normal platelet count. There was good correlation between bleeding time and platelet count only when platelet count was lower than 100,000/mm3 (r = -0.76, P less than -0.02).

The use of labetalol for attenuation of the hypertensive response to endotracheal incubation in preeclampsia

Twenty-five women with preeclampsia who were scheduled to undergo cesarean section under general anesthesia were randomly assigned to either a labetalol pretreatment group ( n = 15) or a control group ( n = 10) who did not receive any antihypertensive therapy before the induction of anesthesia. Patients in the labetalol group received 20 mg of labetalol intravenously followed by 10 mg increments up to a total dose of 1 mg/kg, which resulted in moderate reductions in the maternal mean arterial pressure and heart rate with attenuation of the hypertensive and tachycardiac responses to laryngoscopy and endotracheal intubation. In the labetalol group there was no excessive reduction in the mean arterial pressure with the use of isoflurane and the usual amount of blood loss that occurred during cesarean section. The neonatal Apgar scores and umbilical arterial and venous pH and blood gas values were similar in the two groups. Side effects such as hypotension, bradycardia, and hypoglycemia were not seen in the neonates in the labetalol treatment group.

Anesthetic modification of hemodynamic and neuroendocrine stress responses to cesarean delivery in women with severe preeclampsia

We conducted a prospective evaluation of the comparative effects of lumbar epidural and general anesthesia on the hemodynamic and neuroendocrine stress response to cesarean delivery in 21 women with severe preeclampsia. In the epidural group (n = 11), anesthesia extending to the T-4 dermatome level was obtained using 2% plain lidocaine in divided doses. In the general anesthesia group (n = 10), anesthesia was induced after pretreatment with labetalol or nitroglycerin. In the epidural group, mean arterial pressure (MAP) gradually decreased from 133.3 +/- 5.6 mm Hg to 119 +/- 4.4 mm Hg (P less than 0.002). After pretreatment with labetalol or nitroglycerin, MAP in the general group decreased from 131.5 +/- 4.9 mm Hg to 112.2 +/- 3.5 mm Hg (P less than 0.001). At skin incision (after tracheal intubation), MAP increased from 112.2 +/- 3.5 mm Hg to 143 +/- 5.4 mm Hg (P less than 0.001); however, this was not significantly different from baseline MAP. In the epidural group, there were no further changes in MAP. The difference in MAP at skin incision and postpartum period between the two groups was significant (P less than 0.004 and P less than 0.009, respectively). In the general anesthesia group, both adrenocorticotropic hormone and beta-endorphin-like immunoactivity increased significantly from base levels at skin incision. The catecholamines also increased significantly and remained so throughout the study period. In the epidural group, the concentrations of these hormones decreased or remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuromuscular transmission studies in preeclamptic women receiving magnesium sulfate

The purpose of the study was to evaluate the neuromuscular transmission defect in preeclamptic women receiving intravenous magnesium sulfate and to study the correlation of the degree of defect with serum magnesium and calcium levels. The study population included: group 1, 14 preeclamptic women receiving magnesium sulfate and undergoing induction of labor; group 2, six preeclamptic women studied in the postpartum period while receiving magnesium sulfate; and group 3, 10 normotensive women undergoing induction of labor. The neuromuscular transmission studies were performed with standard techniques before and during the administration of magnesium sulfate. During magnesium sulfate therapy patients in groups 1 and 2 showed abnormal responses characterized by an initial low-amplitude muscle action potential followed by a progressive increase in the amplitudes of the successive responses. There was significant correlation between the degree of the neuromuscular transmission defect and serum magnesium levels, serum calcium levels, and the magnesium/calcium ratio in groups 1 and 2. All studies were normal in group 3. The findings confirm the occurrence of abnormal neuromuscular transmission in preeclamptic women receiving magnesium sulfate, and the intensity of the defect correlates significantly with increased serum magnesium levels and decreased serum calcium levels.

The case for magnesium sulfate in preeclampsia-eclampsia

Preeclampsia-eclampsia is a syndrome of unknown etiology that is unique to human pregnancy. During the past century, numerous theories regarding its etiology have been suggested, but most have not withstood the test of time. Some of the theories that are still under consideration include abnormal placentation, cardiovascular maladaptation, immunologic intolerance between maternal and fetal tissues, genetic and dietary deficiencies. This syndrome complicates about 7% of all pregnancies; however, it remains a major cause of maternal and perinatal morbidity and mortality worldwide.’ In addition, the incidence of preeclampsia-eclampsia varies according to the population studied and the criteria used for establishing the diagnosis. The incidence is significantly increased in nulliparous women, in women with multiple gestation, and in those with previous preeclampsiaeclampsia and in women with underlying vascular or renal disease. Eclampsia is defined as the development of convulsions or coma during pregnancy or postpartum in patients with signs and symptoms of preeclampsia. In recent years the reported incidence of eclampsia ranged from 1 in 110 to 1 in 3448 pregnancies.2 The incidence reaches 3.6% in women with twin pregnancy.3 The extremely low incidence reported from some countries indicates that appropriate prenatal care, astute medical judgement, and early hospitalization of patients with preeclampsia will prevent most cases of eclampsia.2

Crack cocaine, myocardial infarction, and troponin I levels at the time of cesarean delivery.

IMPLICATIONS During the peripartum period, cocaine-abusing women are highly susceptible to myocardial infarction. This report describes a case of myocardial infarction diagnosed by increased troponin I levels in a pregnant patient with a history of recent crack cocaine use and severe preeclampsia.

Changes in maternal middle cerebral artery blood flow velocity associated with general anesthesia in severe preeclampsia.

UNLABELLED In women with severe preeclampsia, significant increases in mean arterial pressures (MAP) are common after rapid induction of general anesthesia (GA) and tracheal intubation. The objectives of this prospective study were to assess the effects of the rapid induction-intubation technique on middle cerebral artery (MCA) flow velocity in severe preeclampsia and to examine the correlation between mean MCA flow velocity (Vm) and MAP. Eight women with severe preeclampsia (study group) and six normotensive women at term (control group) scheduled to undergo cesarean section under GA were studied. Before induction, patients in the study group received i.v. labetalol in divided doses to lower diastolic pressures to <100 mm Hg. Anesthesia was induced with pentothal 4-5 mg/kg, followed by succinylcholine 1.5 mg/kg to facilitate tracheal intubation. A transcranial Doppler was used to measure Vm. Both Vm and MAP were recorded before induction and every minute for 6 min after intubation. In the study group, after the administration of labetalol, MAP decreased from 129 +/- 9 to 113 +/- 9 mm Hg (P < 0.05), and Vm decreased from 59 +/- 11 to 54 +/- 10 cm/s (P < 0.05). After intubation, MAP increased from 113 +/- 9 to 134 +/- 5 mm Hg (P < 0.001), and Vm increased from 54 +/- 10 to 70 +/- 10 cm/s (P < 0.001). In the control group, while MAP increased significantly from 89 +/- 6 to 96 +/- 4 mm Hg (P < 0.05) after intubation, the concurrent increase in Vm from 49 +/- 5 to 54 +/- 7 cm/s was not significant. There was a significant positive pooled correlation between Vm and MAP (r = 0.5, P < 0.0006) in the study group but not in the control group (r = 0.24). After induction and intubation, both Vm and MAP values were significantly increased in the study group patients at all observation points compared with the control group patients. The findings indicate that Vm increases significantly after rapid-sequence induction of GA and tracheal intubation in women with severe preeclampsia, and there seems to be a direct relationship between MAP and Vm. IMPLICATIONS In women with severe preeclampsia, rapid-sequence induction of general anesthesia and tracheal intubation can cause severe hypertension. Our results indicate that the increase in blood pressure is associated with a significant increase in maternal cerebral blood flow velocity and that there is a significant correlation between these two variables.

NEUROMUSCULAR TRANSMISSION STUDIES IN PREECLAMPTIC WOMEN RECEIVING MAGNESIUM SULFATE

The purpose of the study was to evaluate the neuromuscular transmission defect in preeclamptic women receiving intravenous magnesium sulfate and to study the correlation of the degree of defect with serum magnesium and calcium levels. The study population included: group 1, 14 preeclamptic women receiving magnesium sulfate and undergoing induction of labor; group 2, six preeclamptic women studied in the postpartum period while receiving magnesium sulfate; and group 3, 10 normotensive women undergoing induction of labor. The neuromuscular transmission studies were performed with standard techniques before and during the administration of magnesium sulfate. During magnesium sulfate therapy patients in groups 1 and 2 showed abnormal responses characterized by an initial low-amplitude muscle action potential followed by a progressive increase in the amplitudes of the successive responses. There was significant correlation between the degree of the neuromuscular transmission defect and serum magnesium levels, serum calcium levels, and the magnesium/calcium ratio in groups 1 and 2. All studies were normal in group 3. The findings confirm the occurrence of abnormal neuromuscular transmission in preeclamptic women receiving magnesium sulfate, and the intensity of the defect correlates significantly with increased serum magnesium levels and decreased serum calcium levels.