Background: A total artificial lung (TAL) may offer a bridge to recovery or transplantation. Utilizing our recently developed paracorporeal TAL in a 7-day survival study, we critically review perioperative care and anesthetic management. Methods: Adult Suffolk ewes (n=4) underwent general anesthesia induced using 350-500 mg ketamine (7-15 mg/kg, IM), buprenorphine 0.3 mg IM, and 5% halothane by face mask; then maintained by halothane (inspired 1.5-2.5%) in 100% O2 (2.0-2.5 L/min) titrated to keep MAP 70-110 mmHg. Vent settings kept peak airway pressures < 25 mm H2O and end tidal CO2 30-40 mmHg. An 8 cm left Latissimus-sparing thoracotomy provided exposure to anastamose (end-to-side) two 42 Fr VAD arterial cannulas to the proximal and distal pulmonary artery (PA) following systemic heparinzation (200 IU/kg). Cannulas were tunneled through a subcostal, extraperitoneal plane and connected to the TAL. A silicone occluder between PA cannulas diverted total pulmonary flow to the TAL. At chest closure, PEEP eliminated atelectasis and bilateral chest tubes (16 Fr) drained pleura and pericardium. Intraoperative crystalloids were 500 ml prime, IL bolus, then 10ml/kg/hr; postoperative, 2 ml/kg/hr and a heparin drip titrated to ACT 250-300 sec. Buprenorphine (0.3 mg IM tid) controlled pain. Hemodynamic parameters, ABGs, and ACTs were measured every six hours. Results: All sheep survived TAL implantation, were extubated within 15 min. and standing within 1-5 hrs. Hemodynamic parameters did not significantly differ from baseline per animal, averaging: (MAP 82-104 mmHg; PAP 16-23 mmHg; CVP 3-11 mmHg and HE 74-118). Normal ABGs were maintained: pH 7.35-7.55; PaCO2 25-43 mmHg; PaO2 80 - 120 mmHg. TAL CO2 transfer averaged 58-105 ml/min. Complications included intraoperative hemodynamic instability (1) and arrhythmia (1). One oxygenator was replaced due to thrombosis. Two side-mounted stopcocks (now eliminated from the prototype) broke on the TAL; both sheep exsanguinated at 40 and 114 hours. Two sheep were sacrificed on day 7. Conclusion: Our technique of TAL management allows rapid recovery and up to 1 week survival in sheep.
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine