RESPIRATORY COMPLICATIONS AFTER CORONARY-ARTERY BYPASS-SURGERY WITH UNILATERAL OR BILATERAL INTERNAL MAMMARY ARTERY GRAFTING

Background and study objective: Use of bilateral internal mammary arte ry (IMA) grafts during coronary artery revascularization procedures ca rries the potential for increased incidence of postoperative respirato ry complications compared with use of unilateral IMA grafts. The purpo se of this study was to compare the incidence of respiratory complicat ions such as hypoxemia, atelectasis, pleural effusion, and diaphragmat ic dysfunction in patients mho received one or both IMAs as conduit gr afts. Design: Prospective, comparative study. Setting: Surgical ICU at a tertiary teaching hospital. Patients: Seventy-five patients with bi lateral and 75 patients with unilateral IMA grafts. Measurements: Seri al postoperative PaO2/fraction of inspired oxygen measurements, radiog raphic scores of atelectasis and pleural effusion, duration of mechani cal ventilation, length of ICU and hospital stay, and incidence of pne umothorax, pneumonia, and wound infection. Results: There tvas a highe r incidence (51% vs 25%; p=0.002) and severity (0.48+/-0.09 vs 0.15+/- 0.05 on the first postoperative day, 0.39+/-0.07 vs 0.27+/-0.07 on the fourth postoperative Clay, mean+/-SEM; p=0.004) of postoperative righ t lower lobe atelectasis in the group who received bilateral IMA graft s than in those who received left IMA grafts. This finding probably re flects the effects of additional surgical intervention on the right si de of the chest. Incidence and severity of pleural effusion, gas excha nge impairment, duration of mechanical ventilation, ICU and hospital s tay, and incidence of pneumothorax, pneumonia, and wound infection wer e not influenced by use of bilateral IMA grafts (p>0.05). Conclusion: We conclude that use of bilateral IMA. grafts during coronary artery r evascularization does not increase the incidence of postoperative resp iratory complications compared with unilateral IMA grafting.