1. Comparing nasopharyngeal apnoeic oxygenation at 18 l/min to preoxygenation alone in obese patients - A randomised controlled study.
- Author
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Pierpoint SA and Burke JL
- Subjects
- Adult, Humans, Respiration, Artificial, Oxygen, Nasopharynx, Oxygen Inhalation Therapy adverse effects, Apnea etiology, Apnea therapy, Obesity, Morbid complications
- Abstract
Study Objective: Investigate a low-cost, nasopharyngeal apnoeic oxygenation technique, establish its efficacy, and compare it to preoxygenation only in an obese population. The study's hypothesis was that nasopharyngeal apnoeic oxygenation at 18 l.min
-1 would significantly prolong safe apnoea time compared to preoxygenation alone., Design: Randomised controlled study., Setting: Theatre complex of a resource constrained hospital., Patients: 30 adult, obese (BMI ≥ 35 kg.m-2 ) patients presenting for elective surgery. Patients with limiting cardio-respiratory disease, suspected difficult airway, risk of aspiration, and that were pregnant, were excluded. Patients were allocated by block randomisation in a 1:2 ratio to a preoxygenation-only (No-AO) and an intervention group (NPA-O2 )., Interventions: All patients were preoxygenated to an Et-O2 > 80%, followed by a standardised induction. The intervention group received oxygen at 18 l.min-1 via the nasopharyngeal catheter intervention. The desaturation process was documented until an SpO2 of 92% or 600 s was reached., Measurements: Baseline demographic and clinical characteristics were collected. The primary outcome was safe apnoea time, defined as the time taken to desaturate to an SpO2 of 92%. Secondary outcomes were rate of carbon dioxide accumulation and factors affecting the risk of desaturation., Main Results: The study was conducted in a morbidly obese population (NoAO = 41,1 kg.m-2 ; NPA-O2 = 42,5 kg.m-2 ). The risk of desaturation was signifantly lower in the intervention group (Hazzard Ratio = 0,072, 95% CI[0,019-0,283]) (Log-Rank test, p < 0.001). The median safe apnoea time was significantly longer in the intervention group (NoAO = 262 s [IQR 190-316]; NPA-O2 = 600 s [IQR 600-600]) (Mann-Whitney-U test, p < 0.001). The mean rate of CO2 accumalation was significantly slower in the intervention group (NoAO = 0,47 ± 0,14 kPa.min-1 ; NPA-O2 = 0,3 ± 0,09 kPa.min-1 ) (t-test, p = 0.003). There were no statistically significant risk factors associated with an increased risk of desaturation found., Conclusions: Nasopharyngeal apnoeic oxygenation at 18 l/min prolongs safe apnoea time, compared to preoxygenation alone, and reduces the risk of desaturation in morbidly obese patients., Clinical Trial Registration: PACTR202202665252087; WC/202004/007., Competing Interests: Declaration of Competing Interest There were no conflict of interest of either authors in the production of this wok. The research was conducted for completion of Degree purposes. There was no funding, grants, stock ownership or patent applications made. There are no academic disclosures to mention., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2023
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