Short-term effects of low-volume resuscitation with hypertonic saline and hydroxyethylstarch in an experimental model of lung contusion and haemorrhagic shock.

OBJECTIVES

This study aimed to assess the short-term respiratory tolerance and haemodynamic efficiency of low-volume resuscitation with hypertonic saline and hydroxyethylstarch (HS/HES) in a pig model of lung contusion and controlled haemorrhagic shock. We hypothesised that a low-volume of HS/HES after haemorrhagic shock did not impact contused lungs in terms of extravascular lung water 3hours after trauma.

METHODS

A lung contusion resulting from blunt chest trauma was induced in 28 anaesthetised female pigs with five bolt-shots to the right thoracic cage, followed by haemorrhagic shock and fluid resuscitation. Pigs were randomly allocated into two groups: fluid resuscitation by 4ml/kg of HS/HES, or fluid resuscitation by 10ml/kg of normal saline (NS). Monitoring was based on transpulmonary thermodilution and a pulmonary artery catheter. After 3h, animals were euthanized to measure extravascular lung water (EVLW) by gravimetry.

RESULTS

Blunt chest trauma was followed by a transient collapse and hypoxaemia in both groups. Post-mortem gravimetric assessment demonstrated a significant difference between EVLW in the NS-group (8.1±0.7ml/kg) and in the HS/HES-group (6.2±0.6ml/kg, P=0.038). Based on a pathological EVLW threshold of > 7ml/kg, results indicated that only the NS-group experienced moderate pulmonary oedema, contrary to the HS/HES-group. After haemorrhagic shock, HS/HES infusion enabled the restoration of effective mean arterial pressure and cardiac index. Intrapulmonary shunting increased transiently after fluid resuscitation but there was no significant impairment of oxygenation.

CONCLUSION

In this pig model of lung contusion, the short-term assessment of fluid resuscitation after haemorrhagic shock with 4ml/kg of HS/HES showed that pulmonary oedema was avoided compared to fluid resuscitation with 10ml/kg of NS.