The Science Journal of the American Association for Respiratory Care

2006 OPEN FORUM Abstracts

Peri-Operative Administration of Aerosolized Prostacyclin via Face Mask and Endotracheal Intubation in a Patient with Severe Pulmonary Hypertension

Mark Siobal BS RRT, Robin Stackhouse MD, Jean-Francois Pittet MD, Julin Tang MD MS, Department of Anesthesia, San Francisco General Hospital, University of California San Francisco

Introduction: Aerosolized prostacyclin (AP) can be an effective treatment for pulmonary hypertension (PH) in the acute care setiing.1 AP selectively dilates pulmonary vasculature, reduces pulmonary arterial pressure (PAP), decreases pulmonary vascular resistance and afterload to the right ventricle (RV). In the peri-operative setting, AP can be effective in preventing RV failure.

Case Summary: A 61 year old female admitted for shortness of breath and pneumonia was found to have large bilateral ovarian tumors and scheduled for an exploratory laparatomy. The patient's pre-operative workup was significant for severe COPD and cor pulmonale with baseline ABG 7.42, 53, 48, 28.0, 9.3 , FEV1 = 25%, FEF 25/75 = 5%, DLCO = 20% of predicted; and severe PH with reduced RV systolic function and an estimated systolic PAP of 75 mmHg by transthoracic echocardiogram. During pre-op assessment, the anesthetic plan was to administer aerosolized prostacyclin intra-operatively to prevent worsening RV function. In the operating room prior to intubation and general anesthesia, a pulmonary artery catheter (Edwards Lifesciences, Irvine, CA) with continuous cardiac output (CCO), RV ejection fraction (EF), and RV end diastolic volume (EDV) monitoring capabilities was inserted to monitor PAP and RV function.  Following baseline hemodynamic measurements and aerosolized albuterol 2.5 mg, the patient received AP 50 ng/kg/min (Flolan, GlaxoSmithKline, Research Triangle Park, NC) via face mask.2 The patient exhibited marked reduction in PAP, increased CCO, and improved RV function. Anesthesia for intubation was induced with etomidate, fentanyl, versed, and rocuronium. General anesthesia was maintained with desflurane, fentanyl, versed, and vecuronium. AP was maintain at 50 ng/kg/min delivered through the anesthesia ventilator circuit.  A total abdominal hysterectomy, bilateral salpingo-opherectomy, lymph node dissection, omentectomy, and appendectomy were performed. The patient received 5.5L crystalloid, 4 units PRBC, and 1.0 L albumin intraoperatively. Estimated blood loss was 2.0L.  Epinephrine infusion 0.02 - 0.03 mcg/kg/min was required for an episode of hypotension following an increase of PEEP to 10. The patient's RV function remained stable during surgery and post-op following transfer to the ICU on AP 50 ng/kg/min. On post-op day 1, to avoid hemodynamic instability, the patient was weaned from mechanical ventilation prior to weaning off AP. Post extubation the patient continued to received AP via face mask.  Two hours post extubation AP was weaned off over a 4 hour period without hemodynamic complications.

Discussion: This case report demonstrates the effectiveness of utilizing this delivery system for aerosolized prostacyclin2 by face mask and by endotracheal intubation during the peri-operative period in a patient with significant RV dysfunction. Inhalation of the alkaline aerosol (approximate pH of 10.5)2 did not cause bronchospasm in this patient with chronic airway obstruction. We conclude that AP can be an effective treatment in high risk patients with severe PH and RV dysfunction in the acute care, critical care, and intra‑operative setting.

PAP (mean) mmHg Pre AP 60/33 (41) Post AP 42/28 (33) IntraOp AP 43/28 (33)* ICU AP 42/25 (31)* PostExtub AP 43/24 (30) AP Off 64/33 (43)*
CCO  L/min 2.3 4.7 5.5 * 5.2* 5.8 6.2*
RV EF % 10 22 --- 24* 20 21*
RVEDV  mL 387 276 --- 272* 313 359*

* average of several recorded measurements

1.     Siobal MS. Aerosolized Prostacyclins. Resp Care 2004;49(6): 640-652.

2.     Siobal MS, Kallet RH, Pittet JF, Warnecke EL, Kraemer RW, Venkayya RV, Tang JF. Description and evaluation of a delivery system for aerosolized prostacyclin Resp Care 2003;48(8):742-753.

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