The effect of sevoflurane induction on the myocardial performance index in healthy individuals
AbstractBackground: The myocardial performance (Tei) index is a simple, reproducible and easily performed measure of cardiac performance. Its ease of use and proven clinical application make this an attractive measure perioperatively. For appropriate use of this index under sevoflurane anaesthesia, drug effects on normal values need to be defined. Methods: A total of 38 ASA 1 patients were consecutively included in this study. Induction was by sevoflurane inhalation. Steady state was defined as 3–5 min spontaneous tidal ventilation with an end-tidal sevoflurane concentration of at least 2.3%. Baseline and steady-state measurements included haemodynamics and four-chamber transthoracic echocardiographic image acquisition. Offline analysis focused on tissue Doppler studies of the lateral mitral annulus. Discrete variables before and after induction were compared. Results: Changes in simple haemodynamic variables were as expected (Systolic blood pressure: mean [95% CI] –11.62 [–15.96 to –7.27]; diastolic blood pressure: mean [95% CI] –6.46 [–11.65 to –1.28]; heart rate: mean [95% CI] 2.66 [–1.72 to 7.05]). Isovolumic contraction time decreased from baseline (mean [95% CI] –3.37 [–5.11 to –1.64]). Isovolumic relaxation time also decreased (mean [95% CI] –7.44 [–10.23 to –4.66]). Ejection time decreased (mean [95% CI] –4.41 [–11.62 to 2.80]). This saw a consistent decrease in the Tei index with a p-value of < 0.0001 (mean [95% CI] –0.035 [–0.050 to –0.021]). Conclusion: Sevoflurane at 1-MAC minimally decreases the Tei index. This implies that, overall, myocardial mechanics/performance in healthy individuals is not negatively affected by sevoflurane anaesthesia. Reference values for this index appear to be applicable for patients under sevoflurane anaesthesia. (Full text available online at www.medpharm.tandfonline.com/ojaa) South Afr J Anaesth Analg 2017; DOI: 10.1080/22201181.2017.1402536
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