SESSION TITLE: Critical Care Cases
SESSION TYPE: Medical Student/Resident Case Report
PRESENTED ON: Sunday, October 27, 2013 at 07:30 AM - 08:30 AM
INTRODUCTION: Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation that coordinates the delivery of mechanical breaths and the level of inspiratory support with the neural respiratory drive as measured by the diaphragmatic electromyogram. The purpose of this case is to present a scenario where NAVA was used successfully to manage respiratory failure due to Pneumocystis jerovicii pneumonia (PJP) that was refractory to conventional modes of mechanical ventilation (CMMV).
CASE PRESENTATION: A 38 year old male with a history of AIDS, non-compliant with anti-retroviral and prophylactic therapies presented to the hospital with a 3 week history of dyspnea, fever and productive cough. His temperature was 104.4° F, heart rate 156/min, respirations 40/min, and oxygen saturation 89% on 10 L/min supplemental oxygen. Chest exam revealed bilateral scattered rhonchi. The white cell count was 15.9×103/μL, CD4 count 12/mm3. He had an acidosis (pH 7.24) with hypocapnia (PCO2 13 Torr) and hypoxemia (PO2 30 Torr). Lactic acid was 6.6 mmol/L, and lactate dehydrogenase (LDH) was 1198 U/L. Blood and urine cultures were negative, but sputum silver stain revealed Pneumocystis jerovicii . Chest radiograph revealed diffuse bilateral infiltrates, with extensive subcutaneous emphysema, pneumomediastinum and small bilateral pneumothoraces. He was treated with broad-spectrum antimicrobials, trimethoprim-sulfamethoxazole, and prednisone. After developing respiratory arrest he was intubated and placed on pressure support ventilation (PSV). He required increasing PEEP and PS to maintain oxygenation. He remained tachypneic and hypoxemic despite FIO2 of 1.0 and the use of pressure regulated volume control and volume support ventilation. NAVA ventilation was initiated. His hypoxemia improved despite weaning of FIO2. He subsequently demonstrated clinical and laboratory improvement. Radiographs revealed improvement then resolution of pulmonary infiltrates and emphysematous changes. He became less tachypneic and maintained oxygenation when converted back to PSV.
DISCUSSION: Patient-ventilator asynchrony contributes to failure of CMMV and may be circumvented by NAVA. Persistent tachypnea is a component of asynchrony and may have contributed to the failure of conventional ventilation in our patient. Once NAVA was initiated, he maintained adequate oxygenation despite reduction in FIO2. The patient's pneumonia and emphysematous changes improved, and his respiratory rate normalized.
CONCLUSIONS: To our knowledge, this is the first reported case of refractory respiratory distress due to severe PJP with emphysematous changes successfully managed with NAVA. NAVA should be considered in patients refractory to CMMV.
Reference #1: Verbrugghe W, Jorens PG. Neurally adjusted ventilatory assist: a ventilation tool or a ventilation toy? Respir Care 2011;56:327-35.
Reference #2: Thille AW, Rodriguez P, Cabello B, et al. Patient-ventilator asynchrony during assisted mechanical ventilation. Intensive Care Med 2006;32:1515-22.
DISCLOSURE: The following authors have nothing to disclose: Yasin Khan, Bradley Walker, Romana Shehzadi, Steven Conrad
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