CASE REPORT | doi:10.20944/preprints202110.0386.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: Atelectasis; Hypoxia; Old age; Spontaneous respiration
Online: 26 October 2021 (12:36:47 CEST)
There are several causes of hypoxia during and after surgery, and atelectasis is a common symptom that occurs during surgery. In particular, elderly patients are more vulnerable to hypoxia due to their existing lung diseases or respiratory muscle weakness. This study presents the cases of two elderly patients who developed hypoxia during total hip arthroplasty under general anesthesia. Positive end expiratory pressure, recruitment maneuver, and increased fraction of inspired oxygen improved hypoxia only temporarily, and patients’ oxygen saturation level again dropped to 79%–80%. We suspected that hypoxia was caused by atelectasis and, therefore, re-sumed spontaneous respiration. Thereafter, both the patients showed an improvement in hypoxia. Intraopera-tive hypoxia that is suspected to be caused by atelectasis can be improved by securing sufficient lung volume for respiration through increased muscle tone with spontaneous respiration
Mon, 25 October 2021
ARTICLE | doi:10.20944/preprints202110.0339.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: Drosophila melanogaster; TBI; obesity; volatile anesthetics; isoflurane; sevoflurane; preconditioning; mortality; toxicity
Online: 25 October 2021 (10:28:33 CEST)
We tested the hypothesis that obesity influences the pharmacodynamics of volatile general anesthetics (VGAs) by comparing effects of anesthetic exposure on mortality from traumatic brain injury (TBI) in lean and obese Drosophila melanogaster. We induced TBI with a High-Impact Trauma device. Starvation-selection over multiple generations resulted in an obese phenotype (SS flies). Fed flies served as lean controls (FC flies). Adult (1-7 day old) SS and FC flies were exposed to equianesthetic doses of isoflurane or sevoflurane either before or after TBI. The principal outcome was percent mortality 24 hours after injury, expressed as the Mortality Index at 24 hours (MI24). TBI resulted in lower MI24 in FC than in SS flies (21 (2.35) and 57.8 (2.14), respectively n= 12, p=0.0001). Preexposure to isoflurane or sevoflurane preconditioned FC flies to TBI reducing the risk of death to 0.53 [0.25 to 1.13] and 0.82 [0.43 to 1.58], respectively, but had no preconditioning effect in SS flies. Postexposure to isoflurane or sevoflurane increased the risk of death in SS flies. Only postexposure to isoflurane increased the risk in FC flies (1.39 [0.81 to 2.38]). Thus, obesity affects the pharmacodynamics of VGAs, thwarting the preconditioning effect of isoflurane and sevoflurane in TBI.
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