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Transpulmonary pressure and lung elastance can be estimated by a PEEP ‐step manoeuvre
Author(s) -
LUNDIN S.,
GRIVANS C.,
STENQVIST O.
Publication year - 2015
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/aas.12442
Subject(s) - transpulmonary pressure , medicine , positive end expiratory pressure , lung volumes , tidal volume , anesthesia , mechanical ventilation , pulmonary gas pressures , ards , respiratory system , lung
Background Transpulmonary pressure is a key factor for protective ventilation. This requires measurements of oesophageal pressure that is rarely used clinically. A simple method may be found, if it could be shown that tidal and positive end‐expiratory pressure ( PEEP ) inflation of the lungs with the same volume increases transpulmonary pressure equally. The aim of the present study was to compare tidal and PEEP inflation of the respiratory system. Methods A total of 12 patients with acute respiratory failure were subjected to PEEP trials of 0‐4‐8‐12‐16 cmH 2 O . Changes in end‐expiratory lung volume (Δ EELV ) following a PEEP step were determined from cumulative differences in inspiratory‐expiratory tidal volumes. Oesophageal pressure was measured with a balloon catheter. Results Following a PEEP increase from 0 to 16 cmH 2 O end‐expiratory oesophageal pressure did not increase (0.5 ± 4.0 cmH 2 O ). Average increase in EELV following a PEEP step of 4 cmH 2 O was 230 ± 132 ml. The increase in EELV was related to the change in PEEP divided by lung elastance (El) derived from oesophageal pressure as Δ PEEP /El. There was a good correlation between transpulmonary pressure by oesophageal pressure and transpulmonary pressure based on El determined as Δ PEEP /Δ EELV , r 2 = 0.80, y = 0.96x, mean bias −0.4 ± 3.0 cmH 2 O with limits of agreement from 5.4 to −6.2 cmH 2 O (2 standard deviations). Conclusion PEEP inflation of the respiratory system is extremely slow, and allows the chest wall complex, especially the abdomen, to yield and adapt to intrusion of the diaphragm. As a consequence a change in transpulmonary pressure is equal to the change in PEEP and transpulmonary pressure can be determined without oesophageal pressure measurements.