Effect of low dose phenylephrine infusion on shivering and hypothermia in patients undergoing cesarean section under spinal anesthesia: a randomized clinical trial.

BACKGROUND: Shivering is a common complication of spinal anesthesia. Phenylephrine, due to its peripheral vasoconstrictive effect, may limit the core to periphery redistribution of body temperature following spinal anesthesia, and reduce hypothermia and shivering. We hypothesized that prophylactic phenylephrine infusion would reduce shivering and hypothermia in women undergoing cesarean section under spinal anesthesia. METHODS: A two-arm randomized, double-blind, placebo-controlled trial in term pregnant patients undergoing cesarean section. In the phenylephrine group (n=75) prophylactic phenylephrine infusion was administered at 25 µg/min immediately after initiation of spinal anesthesia and continued until the end of the operative period. In the placebo group (n=75) a normal saline infusion was administered during the same period. The primary outcome was the incidence of shivering; secondary outcomes were severity of shivering, changes in nasopharyngeal (core) temperature, and incidence of hypotension and bradycardia. RESULTS: The incidence of shivering in the phenylephrine and control groups was 24.0% (95% CI 14.3% to 33.7%) and 53.3% (95% CI 42.0% to 64.6%), respectively. The severity of shivering was greater in the control group (P=0.002) and the mean (±SD) end of surgery core temperature was significantly higher in the phenylephrine group (35.84°C ±â€¯0.60) compared with controls (35.61°C ±â€¯0.48) (P=0.009). The incidence of hypotension was higher in controls (53.4% vs. 2.7%; P <0.001) but bradycardia more frequent in group P (P=0.023). CONCLUSION: The incidence of shivering and degree of hypothermia were significantly reduced by a prophylactic phenylephrine infusion during cesarean section under spinal anesthesia.

Comparison of conventional C-MAC video laryngoscope guided intubation by anesthesia trainees with and without Frova endotracheal introducer: A randomized clinical trial.

BACKGROUND AND AIMS: Successful intubation with video laryngoscopes necessitates good hand-eye coordination and the use of intubation adjuncts like bougie and stylet. We proposed this study to find whether using Frova introducer with C-MAC video laryngoscope will reduce the intubation time in trainee anesthesiologists. MATERIAL AND METHODS: We enrolled 140 adults without any difficult airway predictors. They were randomly assigned to undergo C-MAC video laryngoscope guided intubation by anesthesia residents using tracheal tube preloaded over Frova introducer (n = 70) or without Frova introducer (n = 70). Primary outcome was the intubation time. Secondary outcomes were the number of redirections of tracheal tube or Frova introducer toward glottis, need for external laryngeal maneuvers (ELMs), first attempt intubation success rate, and ease of intubation. RESULTS: The median actual intubation time (IQR) in Frova and non-Frova group, respectively, were 25.46 (28.11-19.80) and 19.96 (26.59-15.52) s (P = 0.001). The number of redirections of TT or Frova introducer toward glottis, first attempt success rate, and ease of intubation were comparable. The need for ELMs [n (%)] was 15 (21.4) and 26 (37.1) in Frova and non-Frova group, respectively (P = 0.04). CONCLUSION: Frova introducer guided endotracheal intubation with C-MAC videolaryngoscope in patients with normal airways had a marginally prolonged intubation time with a significant reduction in the need of external laryngeal manoeuvres but with a comparable number of redirections and attempts. Further research is needed to generalize these findings to patients with difficult airways.

Comparing slow and rapid bolus of ephedrine in pregnant patients undergoing planned cesarean section under spinal anesthesia.

BACKGROUND AND AIMS: While ephedrine was the preferred drug for treating spinal-induced hypotension in pregnancy, its use has declined because of resultant fetal acidosis. The objective of this randomized control trial was to compare the effects of a slow and rapid bolus of ephedrine on fetal acidosis, maternal blood pressure, and heart rate (HR) during cesarean section performed under spinal anesthesia. MATERIAL AND METHODS: Eighty full-term parturients scheduled for cesarean section under spinal anesthesia were randomly allocated into two groups. While both groups received 6 mg of ephedrine to treat hypotension, Group R (n = 40) received it as a rapid intravenous bolus and Group S (n = 40) received it slowly over 20 s with an infusion pump. The maternal vital parameters were recorded until delivery of the baby using a video camera. Umbilical cord blood was obtained using the three clamp method. Hemodynamic parameters, fetal acidosis, total number of ephedrine bolus used, peak HR after the ephedrine bolus, and occurrence of postoperative nausea and vomiting (PONV) were compared between the groups. RESULTS: Mean increase in HR and blood pressure were significantly higher in Group R than the Group S after the first ephedrine bolus. Umbilical artery pH was significantly lower in Group R than in Group S (7.2 [6.8-7.3] vs. 7.3 [7.3-7.4], P < 0.01). A total number of ephedrine boluses were comparable in the two groups. 35% of the patients had PONV in Group R, whereas none had it in Group S (P < 0.01). CONCLUSION: Slow bolus of ephedrine is better than rapid bolus to treat spinal-induced hypotension during cesarean section in view of less fetal acidosis.

Comparison of different regimens of intravenous dexmedetomidine on duration of subarachnoid block.

BACKGROUND AND AIMS: Many studies have studied the effect of intravenous dexmedetomidine on the prolongation of the duration of the subarachnoid block (SAB). These studies had administered dexmedetomidine using different regimens. This study was designed to find out the suitable regimen with maximum advantages and minimum disadvantages. MATERIAL AND METHODS: Ninety-three ASA 1 and 2 patients scheduled to undergo surgeries under SAB were randomly allocated into three groups namely B, M, and BM. After SAB, Group B received 0.5 µg/kg of dexmedetomidine bolus over 15 min, Group M received 0.5 µg/kg/h of dexmedetomidine infusion until the end of surgery, Group BM received both bolus and infusion. RESULTS: The time to achieve T10 sensory level (SL) was significantly faster in the Groups B and BM than in the Group M. Maximum block height achieved was T4 and was same in all the groups. The Time to achieve maximum SL and Bromage 3 was comparable in all groups. The two-segment regression time and time to reach Bromage 0 was significantly higher in Groups M and BM than Group B. The time for a first request of analgesia was similar in Groups M and BM. The maximum sedation attained in all groups was Ramsay Sedation Score of 3. Side effects such as bradycardia, hypotension, and desaturation were comparable between the groups. CONCLUSION: We conclude that the continuous infusion of dexmedetomidine results in more advantages than just a bolus dose. Therefore, we suggest using only the maintenance dose of intravenous dexmedetomidine after subarachnoid blockade for prolonging the duration and achieving sedation.