Respiratory dead space under anaesthesia in patients with mitral stenosis.
Physiological deadspace (VDphys) and arterial to end-tidal carbon dioxide tension difference [P(a-E)CO2] were calculated under anaesthesia in 27 patients with mitral stenosis planned for close mitral commissurotomy and in 15 healthy individuals for elective non-thoracic surgical procedures. A square wave inspiratory flow pattern and an end-inspiratory pause (25% and 10% of cycle time respectively) were given with a SERVO 900B ventilator used at respiratory rate of approximately 16 per min. An infra-red CO2 analyser was used to measure CO2 production and end-tidal CO2 concentration. Measurements were made prior to the start of the surgery after a minimum of 10 min of stable ventilation to avoid the effect of surgery. Patients with multiple stenosis had significantly higher VDphys (4.28 +/- 1.02 ml kg-1 as compared to 2.10 +/- 0.52 ml kg-1 in controls, P less than 0.001), higher P(a-E)CO2 [0.43 +/- 0.51 kPa as compared to -0.02 +/- 0.23 kPa, P less than 0.01] and lower respiratory system compliance (Crs). Péco2 was positively correlated with PaCO2 in both groups (P less than 0.01). PaO2 was lower in mitral stenosis patients and P(A-a)O2 negatively correlated to Crs (P less than 0.01).
Puri
G D
GD
Department of Anaesthesiology, Postgraduate Institute of Medical Education, Chandigarh, India.
D000328:Adult; D000771:Anesthesia, Intravenous; D002245:Carbon Dioxide / Q000032:analysis / Q000097:blood; D005260:Female; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008946:Mitral Valve Stenosis / Q000503:physiopathology* / Q000601:surgery; D008991:Monitoring, Physiologic; D009020:Morphine / Q000008:administration & dosage; D010100:Oxygen / Q000097:blood; D010197:Pancuronium / Q000008:administration & dosage; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology; D012126:Respiratory Dead Space / Q000502:physiology*; D013874:Thiopental / Q000008:administration & dosage; D013990:Tidal Volume
D002245:Carbon Dioxide; D009020:Morphine; D010197:Pancuronium; D013874:Thiopental; D010100:Oxygen