Perioperative pulmonary circulatory changes during bilateral total hip arthroplasty under regional anesthesia

Abstract

Background and objectives: The transient and rarely clinically relevant effect of bone and cement embolization during unilateral joint arthroplasty is a known phenomenon. However, available studies do not address events surrounding bilateral total hip arthroplasties, during which embolic load is presumably doubled. To elucidate events surrounding this increasingly used procedure and assess the effect on the pulmonary hemodynamics in the intraoperative and postoperative periods, we studied 24 subjects undergoing cemented bilateral total hip arthroplasty during the same anesthetic session.

Materials: Twenty-four patients without previous pulmonary history undergoing cemented bilateral total hip arthroplasty under controlled epidural hypotension were enrolled. Pulmonary artery catheters were inserted and hemodynamic variables were recorded at baseline, 5 mins after the implantation of each hip joint, 1 hr and 1 day after surgery. Mixed venous blood gases and complete blood counts were analyzed at every time point.

Results: An increase in pulmonary vascular resistance was observed after the second but not the first hip implantation when compared with values at incision. Pulmonary vascular resistance remained elevated 1 hr after surgery. Pulmonary artery pressures were significantly elevated on postoperative day 1 compared with those at baseline. The white blood cell count increased in response to the second hip implantation but not the first compared with incision.

Conclusions: The embolization of material during bilateral total hip arthroplasty is associated with prolonged increases in pulmonary artery pressures and vascular resistance, particularly after completion of the second side. Performance of bilateral procedures should be cautiously considered in patients with diseases suggesting decreased right ventricular reserve.

Figure 1

Shown are mean systolic, mean and diastolic pulmonary artery pressures over time. Increases compared to baseline and incision were found postoperatively. Error bars represent 95%-confidence intervals. p<0.003 compared to: #Baseline; †Incision; ‡Hip1; §Hip2

Figure 2

Mean values of pulmonary vascular resistance are depicted at the various time points. An increase compared to incision was seen after the second but not the first hip. This increase lasted into the immediate postoperative period. Error bars represent 95%-confidence intervals. p<0.003 compared to: †Incision

Figure 3

Mean white blood cell counts are shown over time. Values increased in response to the second but not the first hip implantation compared to incision. Error bars represent 95%-confidence intervals. p<0.003 compared to: #Baseline; †Incision; ‡Hip1; §Hip2; ¶1 Hr