The effects of increasing levels of PEEP on oxygenation and lung perfusion in pigs with unilateral lung injury

cc1794 CCJ Meeting abstract The effects of increasing levels of PEEP on oxygenation and lung perfusion in pigs with unilateral lung injury Schreiber T Schwarzkopf K Preussler N Schubert H Gaser E Hüter L Karzai W

Department of Anesthesiology and Intensive Care Medicine, University of Jena, Bachstrasse 18, 07740 Jena, Germany

Department of Experimental Animals, University of Jena, Bachstrasse 18, 07740 Jena, Germany

Critical Care 22nd International Symposium on Intensive Care and Emergency Medicine Meeting abstracts 22nd International Symposium on Intensive Care and Emergency Medicine Brussels, Belgium

19–22 March 2002

1364-8535 2002 6 Suppl 1 P9 10.1186/cc1794 1 3 2002 cc-6-s1-p9

Introduction

The effects of PEEP may differ in healthy and diseased parts of the lung. Accordingly, we studied the effects of increasing PEEP-levels on ventilation, lung perfusion, oxygenation, and hemodynamics in an animal model with unilateral lung injury.

Methods

In 8 pigs (25-36 kg) unilateral lung injury was induced by bronchoscopic application of HCl 0.1 m into the left lung (total: 20-35 ml). Twenty-four hours after injury the pigs were anesthetized, endotracheally intubated with a double-lumen tube and mechanically ventilated. Catheters for hemodynamic monitoring were inserted. Volume controlled ventilation (12 ml/kg body weight, FiO₂ 1.0) with ZEEP, PEEP 5 cmH₂O and PEEP 10 cmH₂O was performed in random order in each animal. Measurements after 45 min of hemodynamic stability in each phase included differential lung perfusion using colored microspheres and differential lung ventilation using the double lumen tube. In 6 pigs (control group) the study was performed without preceding lung injury. ANOVA was used for statistical analysis.

Results and conclusion

After lung injury and in comparison to the control group, left side lung compliance and left side tidal volumes were significantly lower (data not shown). With increasing PEEP, MAP, CO and shunt fraction decreased in both groups.

Compared to the control group, perfusion of the left lung decreased after lung damage, but was not changed by PEEP. Our study shows that PEEP depresses the circulation but does not alter the perfusion of the injured lung during unilateral lung injury.

Table

Lung injury with HCl (n = 8)

Control (n = 6)

ZEEP

PEEP5

PEEP10

ZEEP

PEEP5

PEEP10

PaO₂ (mmHg)

407±17^*

471±11^*

468±22^*

470±22

488±12

525±14

MAP (mmHg)

75±8^**

65±5^**

45±8^**

67±11^**

61±11^**

53±9^**

CO (l/min)

3.6±0.2^**

2.9±0.2^**

2.0±0.1^**

3.8±0.4^**

3.2±0.2^**

2.6±0.2^**

Left lung perfusion (% of total)

30±3^*

30±4^*

30±3^*

50±1.6

47±1.1

57±1.8

Left lung TV (% of total)

29±1.6^*

32±1.2^*

33±1.2^*

45±0.8^*

47±1^*

46±0.6^*

Mean±SEM; CO=cardiac output, MAP=mean arterial pressure, TV=tidal volume. ^*P <0.05 for effects of group. ^**P <0.05 for effects of PEEP.

Slama K Gesch M J Appl Physiol 2000 89 1513 1521 11007590 Ranieri VM Eissa NT Am Rev Respir Dis 1991 144 544 551 1892293