The target adjustment of the end-tidal carbon dioxide partial pressure in preterm infants under mechanical ventilation

Abstract

Objective To reduce the incidence of the hypocapnia, the cutoff value of the end-tidal carbon dio-xide partial pressure[Pet(CO2)] for predicting the hypocapnia so as to understand the suitable adjustment target and target range of the Pet(CO2) in preterm infants under mechanical ventilation. Methods From Jan.2012 to Oct.2013, 96 cases of the preterm infants with respiratory distress syndrome(RDS) who needed mechanical support were selected from the Huaian Maternity and Child Health Care Hospital.Pet(CO2) value of each time point(1 h, 24 h, 48 h and 72 h after mechanical ventilation) were recorded, while radial artery blood was collected for blood gas analysis.The level of pa(CO2) 60 mmHg was for diagnosing hypercapnia.The diagnostic cutoff and the suitable adjustment target and adjustment target range of the Pet(CO2) were confirmed by receiver operating characteristic (ROC) curve. Results The data from 381 arterial blood gas analysis results were gained, of which 151 times belonged to hypocapnia, and the rate was 39.6%, the other 230 cases were normal, and no case was of hypercapnia.The area under the ROC curve was 0.895, and the area of the standard error was 0.016.There was a statistical significance in Pet(CO2) value for the diagnosis of hypocapnia(P= 0.000). The lower the value of Pet(CO2), the greater the likelihood of hypocapnia, and 95% confidence interval area was 0.864-0.926.The Pet(CO2) optimal diagnostic cutoff value determined in accordance with Youden index was 30.5 mmHg.When Pet(CO2) among 41.5 mmHg, sensitivity was 100%. Conclusions Diagnostic cutoff value for forecasting hypocapnia is 30.5 mmHg.The suitable adjustment target of mechanical ventilation parameter adjustment is 41.5 mmHg for the Pet(CO2). The target range of mechanical ventilation parameter adjustment is 30.6-41.5 mmHg for the Pet(CO2). Key words: End-tidal carbon dioxide partial pressure; Infant, preterm; Mechanical ventilation