Alveolar ventilation in children during flexible bronchoscopy.

Abstract

Hypoxia and hypercarbia complicate flexible bronchoscopy (FB). Unlike oxygenation by pulse-oximetry, alveolar ventilation is not routinely monitored during FB. The aim of this study was to investigate ventilation in children undergoing FB by measuring carbon-dioxide (CO2 ) levels using the transcutaneous technique. Children admitted for FB were recruited. In addition to routine monitoring, transcutaneous CO2 (TcCO2 ) levels were recorded. All were sedated using the same protocol. Ninety-five children were studied. There was no association between peak TcCO2 or rise in TcCO2 and age, weight percentile, bronchoscope size, or diagnosis. Median baseline TcCO2 was 36 mmHg (IQR 32,40), median peak TcCO2 was 51 mmHg (IQR 43,62) with median TcCO2 rise of 17 mmHg (IQR 6.5,23.7). A rise of 15 mmHg or higher was recorded in 55% (n = 52) patients. Children requiring total propofol dose over 3.5 mg/kg had a significantly higher TcCO2 peak of 57.6 mmHg (IQR 47.8,66.7) compared to 47.1 mmHg (IQR 40,57) (P = 0.004) and a higher rise in TcCO2 22.5 mmHg (IQR 17,33.9) compared to 13.6 mmHg (6,22) (P = 0.001). Results were not affected by intranasal midazolam and broncho-alveolar lavage. No complications were reported. Non clinically significant (i.e., not lower than 90%) brief drops in oxygen saturation were observed. A large proportion of children undergoing FB have significant alveolar hypoventilation indicated by a rise in TcCO2 . Monitoring ventilation with TcCO2 is feasible and should be added during FB particularly in cases that are expected to require large amounts of sedation and patients susceptible to complications from respiratory acidosis. Pediatr Pulmonol. 2016;51:1177-1182. © 2016 Wiley Periodicals, Inc.