Crystalloid Prehydration versus Cohydration for Prevention Of Hypotension during Spinal Anaesthesia For Elective Caesarean Section

Abstract

Background: Hypotension during spinal anesthesia is a well known problem. Traditionally prehydration before the spinal block is one of the strategies used to prevent hypotension. Recently the efficacy of prehydration has been questioned. Objective: To compare the incidence of hypotension and vasopressor requirement with crystalloid prehydration and cohydration in women undergoing elective caesarean section. Methods: The prospective randomized study was carried out in 120 patients undergoing elective lower segment caesarian section under spinal anaesthesia. They were allocated to receive either 20ml/kg of lactated ringer's solution during 20 minutes prior to induction of spinal anaesthesia (prehydration group) or equivalent volume by rapid infusion immediately after administration of the local anaesthetic intrathecally (cohydration group). Vitals, incidence of hypotension, dose of mephenteramine used and complications were recorded. Results: Hypotension occurred in 19 of 60 patients (31.6%) in prehydration group whereas in 15 of 60 patients (25.0%) in cohydration group, but the difference was not significant (P>0.05). But significantly less patients in the cohydration group (2 of 60 vs 18 of 60) developed hypotension and required vasopressor therapy before delivery of baby (P<0.001). Similarly, parturients in the cohydration group required significantly less dose of mephenteramine for treatment of hypotension. Conclusion: Rapid crystalloid administration after the induction of spinal anaesthesia for elective caesarean section prevents hypotension before delivery and decreases vasopressor requirement.

Crystalloid Coload Reduced the Incidence of Hypotension in Spinal Anesthesia for Cesarean Delivery, When Compared to Crystalloid Preload: A Meta-Analysis

“…In these studies, hypotension was defined as a 20% decrease from baseline in MAP or SBP, or SBP < 90 mmHg. Seven studies [ 11 , 12 , 15 – 18 , 21 ] used ephedrine to treat intraoperative hypotension, two studies [ 14 , 19 ] used ephedrine or phenylephrine, and mephentermine was selected in one study [ 20 ]. Seven studies [ 11 , 12 , 14 , 16 , 17 , 19 , 20 ] used vasopressors when patients developed hypotension, while one study [ 18 ] combined crystalloid boluses and ephedrine.…”

“…Seven studies [ 11 , 12 , 15 – 18 , 21 ] used ephedrine to treat intraoperative hypotension, two studies [ 14 , 19 ] used ephedrine or phenylephrine, and mephentermine was selected in one study [ 20 ]. Seven studies [ 11 , 12 , 14 , 16 , 17 , 19 , 20 ] used vasopressors when patients developed hypotension, while one study [ 18 ] combined crystalloid boluses and ephedrine. Nine studies [ 11 , 12 , 14 – 18 , 20 , 21 ] recorded the number of patients with hypotension throughout the surgery, and one study [ 19 ] recorded hypotension at 3 and 5 min after anesthesia induction.…”

“…Seven studies [ 11 , 12 , 14 , 16 , 17 , 19 , 20 ] used vasopressors when patients developed hypotension, while one study [ 18 ] combined crystalloid boluses and ephedrine. Nine studies [ 11 , 12 , 14 – 18 , 20 , 21 ] recorded the number of patients with hypotension throughout the surgery, and one study [ 19 ] recorded hypotension at 3 and 5 min after anesthesia induction.…”

“…Eight studies [ 11 , 12 , 14 , 16 – 20 ] compared the needs for vasopressors between the preload and coload groups. The results indicated a significant increase in the need for vasopressors when patients received fluid preload (OR = 1.71, 95% CI = 1.07–2.04, and P = 0.02) ( Figure 4(a) ).…”

“…Four studies [ 12 , 15 , 16 , 21 ] reporting on HR during 60 min after spinal anesthesia showed a higher HR in the preload group (MD = 2.18 beats/min, 95% CI = 0.02–4.35, and P = 0.05). Five studies [ 12 , 15 , 16 , 20 , 21 ] on SBP found no significant difference between the groups. Additionally, the preload group had higher MAP during 20 min after spinal anesthesia (MD = 3.25 mmHg, 95% CI = 1.63–4.87, and P < 0.0001) [ 11 , 12 , 16 ].…”