PT  - JOURNAL ARTICLE
AU  - G Hedenstierna
AU  - H Lundquist
AU  - B Lundh
AU  - L Tokics
AU  - A Strandberg
AU  - B Brismar
AU  - C Frostell
TI  - Pulmonary densities during anaesthesia. An experimental study on lung morphology and gas exchange
AID  - 10.1183/09031936.93.02060528
DP  - 1989 Jun 01
TA  - European Respiratory Journal
PG  - 528--535
VI  - 2
IP  - 6
4099  - http://erj.ersjournals.com/content/2/6/528.short
4100  - http://erj.ersjournals.com/content/2/6/528.full
SO  - Eur Respir J1989 Jun 01; 2
AB  - The nature of dense areas in dependent lung regions regularly seen in anaesthetized humans was examined in a sheep model. During anaesthesia with muscle paralysis and mechanical ventilation dense areas in dependent lung regions could be seen by means of computerized tomography (CT). They had the same location and the same attenuation as in anaesthetized humans. Gas exchange impairment tended to increase in proportion to the size of the dense area on the CT scan. Microscopy showed that the densities in the sheep were atelectatic lung regions, with no or little interstitial oedema and only minor vascular congestion. The atelectatic lung tissue was sharply demarcated and the lung tissue in the immediate vicinity was well aerated, or even hyperinflated. Gravimetry showed the same amount of extravascular fluid and blood per unit lung weight in the atelectatic lung and in the aerated lung region. It is concluded that the densities appearing in dependent lung regions during anaesthesia are caused by atelectasis.