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Critical Care

, 14:R93

First Online: 24 May 2010Received: 27 February 2010Revised: 01 May 2010Accepted: 24 May 2010


IntroductionEndotracheal intubation in critically ill patients is associated with severe life-threatening complications in about 20%, mainly due to hypoxemia. We hypothesized that apneic oxygenation via a pharyngeal catheter during the endotracheal intubation procedure would prevent or increase the time to life-threatening hypoxemia and tested this hypothesis in an acute lung injury animal model.

MethodsEight anesthetized piglets with collapse-prone lungs induced by lung lavage were ventilated with a fraction of inspired oxygen of 1.0 and a positive end-expiratory pressure of 5 cmH2O. The shunt fraction was calculated after obtaining arterial and mixed venous blood gases. The trachea was extubated, and in randomized order each animal received either 10 L oxygen per minute or no oxygen via a pharyngeal catheter, and the time to desaturation to pulse oximeter saturation SpO2 60% was measured. If SpO2 was maintained at over 60%, the experiment ended when 10 minutes had elapsed.

ResultsWithout pharyngeal oxygen, the animals desaturated after 103 88-111 seconds median and interquartile range, whereas with pharyngeal oxygen five animals had a SpO2 > 60% for the 10-minute experimental period, one animal desaturated after 7 minutes, and two animals desaturated within 90 seconds P < 0.016, Wilcoxon signed rank test. The time to desaturation was related to shunt fraction R = 0.81, P = 0.002, linear regression; the animals that desaturated within 90 seconds had shunt fractions >40%, whereas the others had shunt fractions <25%.

ConclusionsIn this experimental acute lung injury model, pharyngeal oxygen administration markedly prolonged the time to severe desaturation during apnea, suggesting that this technique might be useful when intubating critically ill patients with acute respiratory failure.

AbbreviationsCrscompliance of the respiratory system

EIPend-inspiratory plateau pressure

FiO2fraction of inspired oxygen

PaCO2partial pressure of arterial carbon dioxide

PaO2partial pressure of arterial oxygen

PEEPpositive end-expiratory pressure

SpO2pulse oximeter oxygen saturation

VTtidal volume.

Electronic supplementary materialThe online version of this article doi:10.1186-cc9027 contains supplementary material, which is available to authorized users.

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Autor: Joakim Engström - Göran Hedenstierna - Anders Larsson


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