Methylmethacrylate induces pulmonary hypertension and increases lung vascular permeability in sheep.

Abstract

Methylmethacrylate (MMA) is a bone cement used to attach prosthetic joints to raw bone surfaces. Occasional reports of pulmonary complications following total hip replacement suggest that MMA may induce pulmonary microvascular abnormalities. We studied the hemodynamic and pulmonary edemagenic effects of 2 mg/kg and 12 mg/kg MMA in 23 sheep. After the 12 mg/kg dose there was a marked fall in mean systemic blood pressure (SBP) within 30 s from 92 +/- 7 to 59 +/- 3 mmHg (p less than 0.05). The SBP returned to normal and then decreased, again becoming significantly lower than baseline at 120 min. Mean pulmonary artery pressure (PAP) increased from 16.8 +/- 1.2 to 27.0 +/- 1.5 mmHg at 0.5 min (p less than 0.01 then slowly returned to normal over 1 h. Despite the transient changes in pulmonary hemodynamics, baseline lymph flow (QL) doubled at 30 min and tripled at 120 min to 3.0 +/- 0.4 and 4.4 +/- 0.6, respectively (p less than 0.01). Lymph/plasma ratio for albumin was 0.83 +/- 0.03 at baseline and was unchanged throughout the study. Lung tissue water/blood free dry weight ratio was 5.4 +/- 0.4 compared to 3.6 +/- 0.3 for normal sheep (p less than 0.05). After the low dose there was no change in SBP or PAP, and QL only doubled (1.0 +/- 0.3 to 2.3 +/- 0.7). The L/P albumin was unchanged. We found no evidence of polymorphonuclear leukocyte (PMN) trapping in the pulmonary parenchyma by lung biopsy or by counts of PMNs in pulmonary artery and aortic blood.(ABSTRACT TRUNCATED AT 250 WORDS)