Entropy-guided end-tidal desflurane concentration during living donor liver transplantation

Abstract

Background:The three phases of living donor liver transplantation (LDLT) represent different liver conditions. The aim is to study the required end-tidal desflurane concentration (ET-Des) guided with entropy monitoring for the depth of anesthesia.Methods:After the Ethics and Research Committee approval, 40 patients were included in this prospective study. Anesthesia was maintained with Desflurane-O2-air. State entropy (SE) and Response entropy (RE) were kept between 40 and 60.Results:Age and Model for End-stage Liver Disease (MELD) score were 45±10 years and 15.43±3.92, respectively. ET-Des were significantly lower in the anhepatic phase (2.8±0.4%) than in the pre-anhepatic and neohepatic phases (3.3±0.3%, 3.47±0.3%, respectively, P<0.001). The SE and RE for pre-anhepatic, anhepatic, and neohepatic phases were (45.6±3.7, 47.4±3.2), (44.7±2.1, 46.4±2.04), and (46.1±3.3, 47.9±3.3), respectively, with no significant changes between the phases, P > 0.05. Total operative time was 651±88 minutes, and for each phase it was 276±11, 195±55, and 191±24 minutes, respectively. Significant changes were found in hemoglobin g/dl and hematocrit % between the three phases (10.28±1.5, 30.48±4.3), (9.45±1.34, 28.36±4.1), and (8.88±1.1, 26.63±3.5), P<0.05. The heart rate and mean blood pressures were stable despite the cardiac index demonstrated a significant reduction during the anhepatic phase (2.99±0.22) when compared to the pre-anhepatic and neohepatic phases (3.60±0.29) and (4.72±0.32), respectively, (P<0.05). There was a significant correlation between CI and ET-Des% (r=0.604, P<0.05).Conclusion:Inhalational anesthetic requirements differed from one phase to another during LDLT, with requirements being the least during the anhepatic phase. Monitoring of the anesthesia depth was required, to avoid excess administration, which could compromise the hemodynamics before the critical time of reperfusion.

The anhepatic phase extended by temporary portocaval shunt does not affect anesthetic sensitivity and postoperative cognitive function

“…[21–27] For this reason, the end-tidal desflurane concentration was fixed at 0.6 age-adjusted MAC, and its corresponding BIS values, which represented anesthetic sensitivity, were obtained in the present study. Unlike the results of the previous studies, which reported the highest anesthetic sensitivity in the anhepatic phase by showing the lowest anesthetic requirements to maintain the desired depth of anesthesia during this phase, [10–12] our results demonstrated that there was no significant change in anesthetic sensitivity at a constant anesthetic concentration during the 3 phases in the non-TPCS group (Table 4). Despite prolongation of the anhepatic phase by TPCS, the interval change in anesthetic sensitivity remained insignificant (Table 4).…”

“…In addition to differences in the methods of anesthetic administration, the insignificant change in anesthetic sensitivity during the 3 phases and its insignificant difference between the 2 groups in the present study might have arisen from the difference in the duration of the anhepatic phase between ours and previous studies [10,11] with data regarding the duration of the anhepatic phase. Interestingly, the average duration of the anhepatic phase extended by TPCS (125.9 minutes) was shorter than the average durations (159 [11] and 195 [10] minutes, respectively) found in previous studies, in which TPCS was not applied.…”

“…Because poor hepatic function is associated with lower anesthetic requirements, [19,20] the anesthetic requirements are expected to be lower during the anhepatic phase than during the other 2 phases. Accordingly, the propofol target concentration required to maintain BIS values between 40 and 50, [12] the end-tidal isoflurane concentration required to maintain BIS values between 40 and 55, [11] and the end-tidal desflurane concentration required to maintain state and response entropy values between 40 and 60 [10] were lowest in the anhepatic phase than in the other phases.…”

“…However, under the above study design, which permitted a liberal change in anesthetic concentrations, [10–12] expectancy bias leading to an intentional decrease in anesthetic dose during the anhepatic phase may have arisen because a broad range of anesthetic concentrations can produce a range of processed electroencephalogram values (e.g., BIS and state and response entropy) required to maintain general anesthesia in a nonlinear pattern. [21–27] For this reason, the end-tidal desflurane concentration was fixed at 0.6 age-adjusted MAC, and its corresponding BIS values, which represented anesthetic sensitivity, were obtained in the present study.…”

“…The dose of anesthetic required to maintain consistent anesthetic depth was lower during the anhepatic phase than during the other 2 phases. [10–12] Because elderly patients with cognitive impairment are more sensitive to anesthetics than those without cognitive impairment, [13] there might be a close relationship between anesthetic sensitivity and cognitive function. Therefore, we evaluated the anesthetic depth achieved by administration of a constant end-tidal minimum alveolar concentration (MAC) of volatile anesthetic during the 3 phases and the postoperative cognitive function in recipients undergoing TPCS, which prolongs the anhepatic phase, to test the hypothesis that extending the anhepatic phase by TPCS enhances sensitivity to anesthetics, leading to the impairment of postoperative cognitive function.…”