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Regional Differences in Lung Function during Anaesthesia and Intensive Care: Clinical Implications
Author(s) -
Hedenstierna G.,
Santesson J.,
Bindslev L.,
Baehrendtz S.,
Klingstedt C.,
Norlander O.
Publication year - 1982
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1982.tb01794.x
Subject(s) - medicine , lung function , intensive care , anesthesia , regional anaesthesia , intensive care medicine , lung
Anaesthesia and most frequently acute respiratory failure are accompanied by a lowered functional residual capacity (FRC). This lowering promotes airway closure in dependent lung units and forces ventilation to non‐dependent regions. Perfusion, on the other hand, is forced towards dependent lung units. A ventilalion‐perfusion mismatch is created and hypoxaemia may develop. General PEEP counters airway closure, but impedes cardiac output and forces perfusion further to dependent regions. In addition, barotrauma may occur. Improved matching of ventilation and perfusion can be achieved by: 1 positioning the subject in the lateral posture; 2 ventilating each lung separately in proportion to its perfusion (differential ventilation); and 3 applying PEEP only to the dependent lung (selective PEEP). Because of less overall intrathoracic pressure and lung expansion, interference with the total lung blood How and the danger of barotrauma should be less than with general PEEP. Improved gas exchange with a 50–100% increase in PaO 2 has been observed in a limited number of patients with acute bilateral lung disease studied so far during differential ventilation and selective PEEP.