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Effectiveness of chest tube clamping in massive hemothorax.

OBJECTIVE
To test the effectiveness of chest tube clamping in massive hemothorax.


DESIGN, MATERIALS AND METHODS
This was assessed in 32 spontaneously breathing Yorkshire piglets with 2.5 mm (groups A and B) or 4.0 mm (groups C and D) lacerations of the thoracic aorta.


MEASUREMENTS
Hemodynamics, blood loss, length of survival, and arterial blood gases (on 100% oxygen) were monitored. The four groups of eight animals all had chest tubes but groups A and C had these tubes clamped. Measurements were made at baseline, immediately after aortic injury, and every 15 minutes until death.


RESULTS
Groups C and D survived 39 +/- 4 and 38 +/- 5 minutes respectively compared to 68 +/- 6 and 70 +/- 4 minutes in groups A and B. Total blood loss was not statistically significantly different among the four groups (1225 +/- 72, 1312 +/- 84, 1020 +/- 90, and 1110 +/- 84 mL for groups A, B, C, and D respectively). The rate of blood loss was greater in groups C and D (29.4 +/- 0.2 mL and 30.1 +/- 0.3 mL/min) compared with 14.7 +/- 0.5 mL and 16.0 +/- 0.9 mL/min respectively in groups A and B. Blood loss rate was similar with clamped or unclamped chest tubes. All groups had similar baseline cardiac output (3.5 to 3.8 L/min) and arterial blood pressures (110 to 114 mm Hg) with a greater decrease in these parameters following the larger lacerations and no difference with chest tube clamping. Arterial PO2 decreased from approximately 400 to 50 mm Hg with clamping but only decreased to approximately 350 mm Hg without clamping. The hypoxia was associated with significant hypercapnea (PCO2 of 78 mm Hg).


CONCLUSIONS
Chest tube clamping did not decrease hemorrhage or mortality but worsened gas exchange without improving hypotension and is therefore not recommended in the treatment of massive hemothorax.