Effective Dose of Prophylactic Oxytocin Infusion During Cesarean Delivery in 90% Population of Nonlaboring Patients With Preeclampsia Receiving Magnesium Sulfate Therapy and Normotensives: An Up-Down Sequential Allocation Dose-Response Study.

BACKGROUND: Oxytocin administration during cesarean delivery is the first-line therapy for the prevention of uterine atony. Patients with preeclampsia may receive magnesium sulfate, a drug with known tocolytic effects, for seizure prophylaxis. However, no study has evaluated the minimum effective dose of oxytocin during cesarean delivery in women with preeclampsia. METHODS: This study compared the effective dose in 90% population (ED90) of oxytocin infusion for achieving satisfactory uterine tone during cesarean delivery in nonlaboring patients with preeclampsia who were receiving magnesium sulfate treatment with a control group of normotensives who were not receiving magnesium sulfate. This prospective dual-arm dose-finding study was based on a 9:1 biased sequential allocation design. Oxytocin infusion was initiated at 13 IU/h, on clamping of the umbilical cord, in the first patient of each group. Uterine tone was graded as satisfactory or unsatisfactory by the obstetrician at 4 minutes after initiation of oxytocin infusion. The dose of oxytocin infusion for subsequent patients was decided according to the response exhibited by the previous patient in the group; it was increased by 2 IU/h after unsatisfactory response or decreased by 2 IU/h or maintained at the same level after satisfactory response, in a ratio of 1:9. Oxytocin-associated side effects were also evaluated. Dose-response data for the groups were evaluated using a log-logistic function and ED90 estimates were derived from fitted equations using the delta method. RESULTS: The ED90 of oxytocin was significantly greater for the preeclampsia group (n = 27) than for the normotensive group (n = 40) (24.9 IU/h [95% confidence interval {CI}, 22.4-27.5] and 13.9 IU/h [95% CI, 12.4-15.5], respectively); the difference in dose requirement was 10.9 IU/h (95% CI, 7.9-14.0; P < .001). The number of patients with oxytocin-related hypotension, defined as a decrease in systolic blood pressure >20% from baseline or to <90 mm Hg, was significantly greater in the preeclampsia group (92.6% vs 62.5%; P = .030), while other side effects such as ST-T depression, nausea/vomiting, headache, and flushing, were not significantly different. There was no significant difference in the need for additional uterotonic or uterine massage, estimated blood loss, and need for re-exploration for uncontrolled bleeding. CONCLUSIONS: Patients with preeclampsia receiving preoperative magnesium therapy need a greater intraoperative dose of oxytocin to achieve satisfactory contraction of the uterus after fetal delivery, as compared to normotensives.

Intraabdominal pressure in non-laboring preeclamptic vs normotensive patients undergoing cesarean section: A prospective observational study.

INTRODUCTION: It is hypothesized that increased intraabdominal pressure (IAP) may be a cause of preeclampsia. There is, however, a paucity of clinical data regarding IAP in preeclamptics. We evaluated and compared the IAP and its effects on organ functions, in normotensive and preeclamptic patients. MATERIAL AND METHODS: Previously healthy non-laboring patients with a singleton pregnancy scheduled for elective cesarean section under subarachnoid block were enrolled (preeclamptic and normotensive; n = 29 each). IAP was measured using an indwelling Foley catheter, and compared in both cohorts at four predefined time points: just before subarachnoid block, immediately after the onset of sensory block to T6 dermatomal level, just after surgery, and 2 hours later. In addition, the presence of organ dysfunction for respiratory, cardiovascular, renal, hepatic, hematopoietic and central nervous systems were evaluated for association with IAP. RESULTS: Although age, body mass index, gravidity, parity, serum bilirubin, serum creatinine, PaO2 /FiO2 ratio and Glasgow coma score of the preeclamptic and normotensive patients were similar, the mean blood pressure was significantly higher (P < 0.001), the period of gestation less (P = 0.003) and the platelet count lower (P = 0.020) in the former. The IAP was significantly higher in the preeclamptic group at all four time points: respectively, 15.1 (1.0) vs 14.2 (0.9) mm Hg (P = 0.002); 14.9 (0.9) vs 14.1 (1.0) mm Hg (P = 0.002), 10.4 (1.0) vs 9.5 (1.3) mm Hg (P = 0.008) and 10.2 (0.8) vs 9.2 (1.2) mm Hg (P = 0.001). There was no correlation between the IAP and various organ dysfunctions. CONCLUSIONS: Preeclampsia is associated with a significantly higher IAP in patients undergoing a cesarean section. The clinical relevance of this finding needs further investigation.

Critically Ill Obstetric Patients: Much more than Meets the Eye.

How to cite this article: Tyagi A, Luthra A, Garg D. Critically Ill Obstetric Patients: Much more than Meets the Eye. Indian J Crit Care Med 2019;23(10):493.

Risk of early postoperative acute kidney injury with stroke volume variation-guided tetrastarch versus Ringer's lactate.

BACKGROUND: Whether intraoperative use of hydroxyethyl starch (HES) solutions is associated with postoperative acute kidney injury (AKI) continues to be researched. Urinary neutrophil gelatinase-associated lipocalin (NGAL) is validated for early detection of AKI. Previous studies are limited and use empirically predefined volumes of HES solutions with serum creatinine as marker for AKI. MATERIALS AND METHODS: Adults scheduled for orthopedic surgery under general anesthesia with >200-300 mL blood loss expected were included; 40 were randomized to receive 6% HES 130/0.4 (tetrastarch) (group HES) or Ringer's lactate (group RL) boluses when stroke volume variation (SVV) >10% in supine or lateral position, or >14% in prone position. Incidence of early postoperative AKI using urinary NGAL (>100 ng/mL) was the primary outcome, and using derangement of serum creatinine was the secondary measure. RESULTS: In 38 patients, intervention was completed, and incidence of AKI (postoperative urinary NGAL >100 ng/mL) among them was 0% in both groups. Patients with urinary NGAL >50 ng/mL were insignificantly higher for group RL versus group HES (6/19 vs. 4/19) (P = 0.461), as were those with incidence of AKI as per creatinine values (5/19 vs. 4/19) (P = 1.000). Group RL had significantly higher requirement of fluid (1211 ± 758 mL vs. 689 ± 394 mL) (P = 0.013) and lower cardiac index (P < 0.05) versus group HES. CONCLUSION: SVV-guided tetrastarch and Ringer's lactate do not result in postoperative AKI diagnosed by urinary NGAL >100 ng/mL; however, an insignificant trend for better renal functions as well as significantly more efficacious volume expansion and hemodynamic stability were seen with tetrastarch instead.