INFLUENCE OF AGE ON ATELECTASIS FORMATION AND GAS EXCHANGE IMPAIRMENT DURING GENERAL ANAESTHESIA

• Published in: British journal of anaesthesia : BJA 1991-04, Vol.66 (4), p.423-432
• Main Authors: GUNNARSSON, L., TOKICS, L., GUSTAVSSON, H., HEDENSTIERNA, G.
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; Anaesthesia; Anesthesia; Anesthesia, General - adverse effects; Anesthesia, Inhalation - adverse effects; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; atelectasis; Biological and medical sciences; Blood Pressure - drug effects; Cardiac Output - drug effects; Complications: age; Enflurane; Female; gas exchange; General anesthesia. Technics. Complications. Neuromuscular blocking. Premedication. Surgical preparation. Sedation; Halothane; Humans; Lung - diagnostic imaging; Lung: atelectasis; Male; Medical sciences; Middle Aged; Partial Pressure; Pulmonary Atelectasis - diagnostic imaging; Pulmonary Atelectasis - epidemiology; Pulmonary Atelectasis - etiology; Pulmonary Gas Exchange - drug effects; Regression Analysis; Tomography, X-Ray Computed; Ventilation-Perfusion Ratio - physiology
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/66.4.423

We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and non-smokers, aged 23–69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P < 0.001) and the alveolar—arterial oxygen partial pressure difference (PAO2 − PaO2) increased with age (P < 0.001). Shunt, assessed by the multiple inert gas elimination technique, was small (mean 0.5%) and uninfluenced by age. However, there was an increasing dispersion (log SD Q) of ventilation/perfusion ratios (VA/Q) and increasing perfusion of regions of low VA/Q (VA/Q