Lennart Edmark1, Kamelia Kostova-Aherdan, Mats Enlund, Göran Hedenstierna. 1. Department of Anesthesiology and Intensive Care, Central Hospital, Västerås, and Research Associate, Department of Medical Sciences, Clinical Physiology, University Hospital, Uppsala, Sweden. lennart.edmark@ltvastmanland.se
Abstract
BACKGROUND: The use of 100% oxygen during induction of anesthesia may produce atelectasis. The authors investigated how different oxygen concentrations affect the formation of atelectasis and the fall in arterial oxygen saturation during apnea. METHODS:Thirty-six healthy, nonsmoking women were randomized to breathe 100, 80, or 60% oxygen for 5 min during the induction of general anesthesia. Ventilation was then withheld until the oxygen saturation, assessed by pulse oximetry, decreased to 90%. Atelectasis formation was studied with computed tomography. RESULTS: Atelectasis in a transverse scan near the diaphragm after induction of anesthesia and apnea was 9.8 +/- 5.2 cm2 (5.6 +/- 3.4% of the total lung area; mean +/- SD), 1.3 +/- 1.2 cm2 (0.6 +/- 0.7%), and 0.3 +/- 0.3 cm2 (0.2 +/- 0.2%) in the groups breathing 100, 80, and 60% oxygen, respectively (P < 0.01). The corresponding times to reach 90% oxygen saturation were 411 +/- 84, 303 +/- 59, and 213 +/- 69 s, respectively (P < 0.01). CONCLUSION: During routine induction of general anesthesia, 80% oxygen for oxygenation caused minimal atelectasis, but the time margin before unacceptable desaturation occurred was significantly shortened compared with 100% oxygen.
RCT Entities:
BACKGROUND: The use of 100% oxygen during induction of anesthesia may produce atelectasis. The authors investigated how different oxygen concentrations affect the formation of atelectasis and the fall in arterial oxygen saturation during apnea. METHODS: Thirty-six healthy, nonsmoking women were randomized to breathe 100, 80, or 60% oxygen for 5 min during the induction of general anesthesia. Ventilation was then withheld until the oxygen saturation, assessed by pulse oximetry, decreased to 90%. Atelectasis formation was studied with computed tomography. RESULTS: Atelectasis in a transverse scan near the diaphragm after induction of anesthesia and apnea was 9.8 +/- 5.2 cm2 (5.6 +/- 3.4% of the total lung area; mean +/- SD), 1.3 +/- 1.2 cm2 (0.6 +/- 0.7%), and 0.3 +/- 0.3 cm2 (0.2 +/- 0.2%) in the groups breathing 100, 80, and 60% oxygen, respectively (P < 0.01). The corresponding times to reach 90% oxygen saturation were 411 +/- 84, 303 +/- 59, and 213 +/- 69 s, respectively (P < 0.01). CONCLUSION: During routine induction of general anesthesia, 80% oxygen for oxygenation caused minimal atelectasis, but the time margin before unacceptable desaturation occurred was significantly shortened compared with 100% oxygen.
Authors: Lars P Thomsen; Dan S Karbing; Bram W Smith; David Murley; Ulla M Weinreich; Søren Kjærgaard; Egon Toft; Per Thorgaard; Steen Andreassen; Stephen E Rees Journal: J Clin Monit Comput Date: 2013-02-21 Impact factor: 2.502
Authors: Mauro R Tucci; Eduardo L V Costa; Tyler J Wellman; Guido Musch; Tilo Winkler; R Scott Harris; Jose G Venegas; Marcelo B P Amato; Marcos F Vidal Melo Journal: Anesthesiology Date: 2013-07 Impact factor: 7.892
Authors: Christian S Meyhoff; Jørn Wetterslev; Lars N Jorgensen; Steen W Henneberg; Inger Simonsen; Therese Pulawska; Line R Walker; Nina Skovgaard; Kim Heltø; Peter Gocht-Jensen; Palle S Carlsson; Henrik Rask; Sharaf Karim; Charlotte G Carlsen; Frank S Jensen; Lars S Rasmussen Journal: Trials Date: 2008-10-22 Impact factor: 2.279