The Effect of Prehydration on Sensory Block Level in the Isobaric Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Even though the effect of prehydration on the spinal anesthesia-induced hypotension has not yet been concluded, prehydration prior to spinal anesthesia is recommended in order to reduce the incidence and severity of hypotension. We investigated the effects of prehydration on hemodynamic change during spinal anesthesia with isobaric 0.5% tetracaine. METHODS: We prospectively performed this study on 96 patients who underwent elective transurethral surgery from October 2002 to January 2004. Patients were randomly allocated to receive either no prehydration or 10 ml/kg crystalloids administered over 10 15 min prior to spinal anesthesia. We compared dermatomal spreads of spinal anesthesia, hemodynamic parameters (blood pressure, heart rate), incidences of hypotension and bradycardia between two groups. RESULTS: Hemodynamic parameters, incidences of hypotension and bradycardia showed no statistically significant differences during spinal anesthesia between two groups. There were statistically significant differences in the dermatomal spread of sensory levels between two groups from 5 to 90 min after spinal anesthesia. Sensory block levels in prehydration group were statistically lower than no prehydration group. CONCLUSION: We hypothesized that prehydration can be one of factors that influence on dermatomal spread of local anesthetics in isobaric spinal anesthesia. The difference of dermatomal spread between two groups may be caused by brain blood barrier (BBB)-freely passing crystalloids, which may influence on the volume and density of cerebrospinal fluids. To verify this phenomenon found in our study, further investigation is still warranted.

Prevention of Hypotension with Crystalloid Versus Colloid During Spinal or Combined Spinal-Epidural Anesthesia for Cesarean Delivery / 대한마취과학회지

BACKGROUND: The prevention of hypotension continues to be one of major challenges in spinal anesthesia (SA) for cesarean delivery. And prehydration is widely performed to prevent hypotension. However, some controversy exists over the types of fluid used for prehydration. Therefore, we investigated the effects of crystalloid versus colloid preload on the incidences of hypotension, and the notion that minimal local anesthetic used in combined spinal-epidural anesthesia (CSEA) could further decrease the incidence of hypotension after colloid preloading. METHODS: One hundred and fifty parturients were randomly allocated into three groups: CR (crystalloid)-SA, CO (colloid)-SA, and CO-CSEA according to the types of preload and anesthesia. In the CR-SA group, 1,000-1,500 ml of crystalloid was administered under spinal anesthesia. In the CO-SA and CO-CSEA groups, 500 ml of colloid followed by 500-1,000 ml of crystalloid under SA and CSEA was administered, respectively. Bupivacaine 9 mg with opioids was used for SA, and bupivacaine 6 mg with opioids and epidural top-up with 0.25% bupivacaine 10 ml for CSEA. Incidences of hypotension, nausea and vomiting were recorded until delivery. RESULTS: Colloid preload reduced the incidence of hypotension (18% vs 44%, P = 0.005), and side effects (2% vs 20%, P = 0.005) compared to crystalloid in SA. However, lowering local anesthetic using CSEA (hypotension 20%, side effects 4%) did not further decrease the incidences of hypotension and side effects when using colloid. CONCLUSIONS: Colloid is a better fluid for prehydration in cesarean section under spinal anesthesia. 18-20% is considered a minimum incidence of hypotension.