Isoflurane versus sevoflurane with interscalene block for shoulder arthroscopic procedures: Value of process capability indices as an additional tool for data analysis

Abstract

Background and Aims:Hypotensive anaesthesia reduces intra-articular bleed and promotes visualisation during arthroscopy. The haemodynamic effects of inhalational agents isoflurane and sevoflurane were studied extensively, and both were found to reduce mean arterial pressures (MBP) to an equivalent magnitude. We investigated the relative ability of isoflurane vis-a-vis sevoflurane to maintain the target systolic blood pressure (SBP) in patients undergoing shoulder arthroscopic procedures.Methods:In a prospective randomised study, 59 patients in two groups of 30 and 29 patients each received concomitant general anaesthesia (1.2–1.5 MAC of isoflurane and sevoflurane) and interscalene brachial plexus block. Nitrous oxide was used in both groups. Intraoperatively, serial blood pressure recordings of SBP, diastolic blood pressure (DBP), MBP and heart rates were done at every 3rd min intervals. The manipulations needed to achieve target SBP (T = 90 mmHg) for optimal arthroscopic visualisation and treat unacceptable hypotensive episodes were noted. Conventional statistical tests and process capability index (PCI) evaluation were both deployed for data analysis.Results:Lower mean SBP and DBPs were recorded for isoflurane patients as compared to sevoflurane (P < 0.05, for mean, maximum and minimum recordings). Higher mean heart rates were recorded for isoflurane (P < 0.05). PCIs indicated that isoflurane was superior to sevoflurane in the ease of achieving target SBP of 90 mmHg as well as maintaining blood pressures in the range of 80–100 mmHg.Conclusion:Isoflurane provides better intraoperative haemodynamic status vis-a-vis sevoflurane in patients undergoing shoulder arthroscopic surgery with preliminary interscalene blockade. The PCI can be a useful additional medical data analysis tool.

Sevoflurane versus isoflurane in shoulder arthroscopy in beach chair position in patients with prior interscalene brachial plexus block: A prospective randomised equivalency-based haemodynamic evaluation trial

“…A few previous studies did focus on comparing haemodynamic effects of different anaesthetic agents, but in the LDP. [ 11 12 ] In contrast to previous findings, we observed equivalent SBPs, MBPs, and HR mean s with both agents in BCP arthroscopy. While rejecting the null hypothesis, we also checked whether sevoflurane could achieve haemodynamic status equivalent with isoflurane.…”

“…Our previous study on shoulder arthroscopy in lateral decubitus position (LDP) demonstrated approximately 10 mmHg mean difference of SBP between group subjects when different techniques and inhalational agents were compared. [ 11 12 ] Based on this, we calculated the sample size for this study. A minimum of 16 patients were required in each group to detect a mean BP difference of 10 mmHg [power 80%, α = 0.05, with standard deviation (SD) of 10 in each group] assuming that differences of <10 mmHg would not be clinically significant.…”

“…PCIs[ 11 14 ] were used to evaluate an individual patient's haemodynamic parameter fluctuations since SDs of individual patients were not assessed during conventional evaluations. We derived PCIs for the desired range of maintained SBP, that is, between 100 and 80 mmHg.…”