Protective effect of therapeutic hypercapnia on lung during one-lung ventilation in patients undergoing pulmonary lobectomy

Abstract

Objective To evaluate the protective effect of therapeutic hypercapnia on the lung during one-lung ventilation(OLV)in the patients undergoing pulmonary lobectomy. Methods Fifty patients of both sexes, aged 20-60 yr, with body mass index 18-30 kg/m2, of American Society of Anesthesiologists physical status Ⅱ, scheduled for elective pulmonary lobectomy, were randomly divided into 2 groups(n=25 each)using a random number table: control group(group C)and therapeutic hypercapnia group(group H). After induction of general anesthesia, the patients were endotracheally intubated and mechanically ventilated in volume-controlled mode.The ventilator settings were adjusted during two-lung ventilation to maintain the end-tidal pressure of carbon dioxide(PETCO2) at 25-35 mmHg.Group H inhaled the mixture of CO2 (3%-6%)and O2(70%-82%)during OLV to maintain PETCO2 at 50-60 mmHg.Group C inhaled O2(70%-88%)during OLV to maintain PETCO2 at 25-35 mmHg.Anesthesia was maintained with inhalation of sevoflurane and intravenous infusion of remifentanil.Immediately before OLV and at 30 min after restoration of two-lung ventilation, the airway peak pressure, airway plateau pressure and lung compliance were recorded, arterial blood samples were collected for blood gas analysis, and broncho-alveolar lavage fluid(BALF)from the collapsed lung and venous blood samples were collected for determination of tumor necrosis factor-alpha(TNF-α), interleukin-1beta(IL-1β), IL-6, IL-8 and IL-10 concentrations in BALF and serum by enzyme-linked immunosorbent assay.Oxygenation index was calculated. Results Compared with group C, the airway peak pressure and airway plateau pressure were significantly decreased, the lung compliance was significantly increased, the concentrations of TNF-α, IL-1β, IL-6 and IL-8 in BALF were significantly decreased, and the concentrations of IL-10 in BALF were significantly increased at 30 min after restoration of two-lung ventilation(P 0.05). Conclusion Therapeutic hypercapnia can improve pneumodynamics and attenuate inflammatory responses, and has no significant difference clinically in improving oxygenation during OLV in the patients undergoing pulmonary lobectomy. Key words: Hypercapnia; Respiration, artificial; Pneumonectomy