biostudies-literatureUnknown14(4)Siddiki H<h4>Introduction</h4>Dead-space fraction (Vd/Vt) has been shown to be a powerful predictor of mortality in acute lung injury (ALI) patients. The measurement of Vd/Vt is based on the analysis of expired CO2 which is not a part of standard practice thus limiting widespread clinical application of this method. The objective of this study was to determine prognostic value of Vd/Vt estimated from routinely collected pulmonary variables.<h4>Methods</h4>Secondary analysis of the original data from two prospective studies of ALI patients. Estimated Vd/Vt was calculated using the rearranged alveolar gas equation: Vd/Vt=1-[(0.86×VCO2est)/(VE×PaCO2)] where VCO2est is the estimated CO2 production calculated from the Harris Benedict equation, minute ventilation (VE) is obtained from the ventilator rateCritical care (London, England)R141https://www.ebi.ac.uk/biostudies/studies/S-EPMC2945122biostudies-literatureBedside quantification of dead-space fraction using routine clinical data in patients with acute lung injury: secondary analysis of two prospective trials.PMC2945122Li GSiddiki HKojicic MYilmaz MThompson TBHubmayr RDGajic OfalseBedside quantification of dead-space fraction using routine clinical data in patients with acute lung injury: secondary analysis of two prospective trials.<h4>Introduction</h4>Dead-space fraction (Vd/Vt) has been shown to be a powerful predictor of mortality in acute lung injury (ALI) patients. The measurement of Vd/Vt is based on the analysis of expired CO2 which is not a part of standard practice thus limiting widespread clinical application of this method. The objective of this study was to determine prognostic value of Vd/Vt estimated from routinely collected pulmonary variables.<h4>Methods</h4>Secondary analysis of the original data from two prospective studies of ALI patients. Estimated Vd/Vt was calculated using the rearranged alveolar gas equation: Vd/Vt=1-[(0.86×VCO2est)/(VE×PaCO2)] where VCO2est is the estimated CO2 production calculated from the Harris Benedict equation, minute ventilation (VE) is obtained from the ventilator rate2010-01-01T00:00:00Z20102025-05-29T20:31:10.747Z2025-05-29T20:31:10.747ZS-EPMC29451222067041110.1186/cc9206