Crystalloid Coload vs Colloid Coload following Spinal Anesthesia for Elective Cesarean Delivery: The Effects on Maternal Central Venous Pressure

Abstract

Introduction: Spinal anesthesia is widely used in the management of uncomplicated cesarean section. Maternal hypotension is the commonest serious problem which decreases uterine blood flow causing fetal hypoxia, acidosis, and neonatal depression. Fluid administration before start of the surgery (preloading) with crystalloid is found to be ineffective due to rapid redistribution of fluids in various tissue spaces. A "coload" given at the time of spinal anesthesia may be more effective. Most studies have concentrated on noninvasive systolic blood pressure (SBP) measurements to evaluate the effect of such regimens. We used central venous pressure (CVP) measurement technique in parturients receiving rapid administration of crystalloid or colloid solution at the time of initiation of anesthesia (coload). We hypothesized that a colloid coload compared with a crystalloid coload would produce a larger sustained increase in volume and therefore reduce vasopressor requirements. Materials and methods:We recruited healthy term women scheduled for elective cesarean delivery under spinal anesthesia for this randomized study. Baseline heart rate, baseline mean arterial blood pressure (MAP), and CVP were recorded. At the time of spinal injection, subjects were allocated to receive a rapid 1 L coload of either polymerized gelatin 3.5% (Haemaccel) or Hartmann (crystalloid) solution. The primary outcome CVP was compared between groups, as were secondary outcomes: phenylephrine dose and maternal hemodynamics data.Results: Maternal demographics, surgical times, and American Society of Anesthesiologists (ASA) were similar between groups. Baseline parameters were similar in all the three groups. Heart rate increased from the baseline in all the three groups; however, mean heart rate was highest in crystalloid group. Mean arterial blood pressure decreased in all the three groups from baseline; however, highest fall was recorded in crystalloid group. The incidence of hypotension was 66.66% in crystalloid group as compared with 36.66% in colloid group. Crystalloid group patients received 6.33 ± 4.54 mg of ephedrine as compared with 2.40 ± 2.82 mg in colloid group. Thus, the incidence of hypotension and ephedrine consumption was significantly higher in crystalloid group as compared with colloid group. We found statistically significant differences in the mean preoperative CVP reading (p < 0.05) between the two groups, the mean CVP reading in crystalloid group being slightly lower. With preloading, similar CVP readings were obtained in both groups. The fall in CVP during subarachnoid blockade was also not significant. The CVP began to fall with the establishment of the block until the delivery of the baby after which it was found to rise. The predelivery CVP was significantly lower than preoperative CVP in both groups-the fall being significantly more in crystalloid group. Conclusion:In our study, the results showed statistically significant decrease in volume requirement, when colloid coload is used than crystalloid coload using C...