Background The General Anesthesia compared to Spinal anesthesia (GAS) study is a prospective randomized, controlled, multi-site, trial designed to assess the influence of general anesthesia (GA) on neurodevelopment at five years of age. A secondary aim obtained from the blood pressure data of the GAS trial is to compare rates of intraoperative hypotension after anesthesia and to identify risk factors for intraoperative hypotension. Methods 722 infants ≤ 60 weeks postmenstrual age undergoing inguinal herniorrhaphy were randomized to either bupivacaine RA or sevoflurane GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born < 26 weeks’ gestation. Moderate hypotension was defined as mean arterial pressure (MAP) measurement of < 35 mm Hg. Any hypotension was defined as mean arterial pressure (MAP) of <45 mm Hg. Epochs were defined as a 5 minute measurement periods. The primary outcome was any measured hypotension <35 mm Hg from start of anesthesia to leaving the operating room. This analysis is reported primarily as intention to treat (ITT) and secondarily as per protocol (APP). Results The relative risk of general anesthesia compared with regional anesthesia predicting any measured hypotension<35 mm Hg from the start of anesthesia to leaving the operating room was 2.8 (CI 2.0, 4.1, p value <0.001) by ITT analysis and 4.5 (CI 2.7,7.4, p value <0.001) by APP analysis In the GA group 87% and 49% and in the RA group 41% and 16% exhibited any or moderate hypotension by ITT, respectively. In multivariable modeling, group assignment (GA vs. RA), weight at the time of surgery and minimal intraoperative temperature were risk factors for hypotension. Interventions for hypotension occurred more commonly in the GA group compared with the RA group (Relative Risk 2.8, 95% CI:1.7,4.4 by ITT). Conclusions RA reduces the incidence of hypotension and chance of intervention to treat it compared with sevoflurane anesthesia in young infants undergoing inguinal hernia repair.

Background and Aims:Routine use of pre-procedural ultrasound guided midline approach has not shown to improve success rate in administering subarachnoid block. The study hypothesis was that the routine use of pre-procedural (not real time) ultrasound-guided paramedian spinals at L5-S1 interspace could reduce the number of passes (i.e., withdrawal and redirection of spinal needle without exiting the skin) required to enter the subarachnoid space when compared to the conventional landmark-guided midline approach.Methods:After local ethics approval, 120 consenting patients scheduled for elective total joint replacements (Hip and Knee) were randomised into either Group C where conventional midline approach with palpated landmarks was used or Group P where pre-procedural ultrasound was used to perform subarachnoid block by paramedian approach at L5-S1 interspace (real time ultrasound guidance was not used).Results:There was no difference in primary outcome (difference in number of passes) between the two groups. Similarly there was no difference in the number of attempts (i.e., the number of times the spinal needle was withdrawn from the skin and reinserted). The first pass success rates (1 attempt and 1 pass) was significantly greater in Group C compared to Group P [43% vs. 22%, P = 0.02].Conclusion:Routine use of paramedian spinal anaesthesia at L5-S1 interspace, guided by pre-procedure ultrasound, in patients undergoing lower limb joint arthroplasties did not reduce the number of passes or attempts needed to achieve successful dural puncture.