Parab SY, Chatterjee A, Saxena RS. The utility of gradient of end-tidal carbon dioxide between two lungs in lateral decubitus position in predicting a drop in oxygenation during one-lung ventilation in elective thoracic surgery- A prospective observational study.
Indian J Anaesth 2021;
65:744-749. [PMID:
34898701 PMCID:
PMC8607859 DOI:
10.4103/ija.ija_591_21]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 10/10/2021] [Accepted: 10/11/2021] [Indexed: 11/09/2022] Open
Abstract
Background and Aims:
Baseline difference in the perfusion of two lungs is the cause of intra-operative shunt during one-lung ventilation (OLV). This study aimed to test the hypothesis that the gradient of end-tidal carbon dioxide (EtCO2) between two lungs in lateral position (D-EtCO2lateral) would predict the quantity of shunt and hence the drop in the oxygenation during OLV.
Methods:
An observational study was conducted to include consecutive 70 patients undergoing thoracic surgery using a double-lumen tube in a lateral position. D-EtCO2lateral was calculated by subtracting EtCO2 from the non-dependent lung from that of the dependent lung when ventilation parameters are the same for each lung. Oxygenation was assessed by measuring PaO2/FiO2 ratios (P/F ratio) at 10, 20 and 40 min after OLV. Correlations between D-EtCO2lateral and P/F ratios were calculated. Receiver operating curves were analysed to test the ability of D-EtCO2lateral to identify patients with a P/F ratio of <100 during OLV.
Results:
A moderate correlation was found between D-EtCO2lateral and P/F ratios at 10 and 20 min of OLV. Among lung resection cases (n = 61), correlation was moderate at 10 (r = 0.64), and 20 min (r = 0.65) (P < 0.001) and became weak at 40 min (r = 0.489, P < 0.001). Areas under curve for D-EtCO2lateral to predict the drop in P/F ratio <100 at 10, 20 and 40 min after OLV were 0.90 (cut-off: 2.5), 0.78 (cut-off: 3.5) and 0.78 (cut-off: 4.5), respectively.
Conclusion:
D-EtCO2lateral could predict the drop in oxygenation in the early part of OLV in lung resection surgeries.
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