The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

HIGH FREQUENCY VENTILATION IN A CASE OF SEVERE ATHROGRYPOSIS MULTIPLEX CONGENITA.

Steve Sitting. RRT, Pediatric-Perinatal Specialist, Scott LeBard, M.D., Mayo Eugenio Litta Children's Hospital, Rochester, Minnesota

Introduction: In this case study we describe how we utilized the Sensormedics 3100 high frequency ventilator in the postoperative management of a 36-kg, 16-year-old male with severe athrogryposis. Case Summary: The patient was admitted for anterior/posterior fusion for progressive scoliosis. A chest x-ray prior to surgery showed a 100° curvature of the spine. Pulmonary function tests revealed a total lung capacity of 46% and an FEV_{1} of 32%. He initially underwent anterior exposure of the thoracolumbar spine for multiple diskectomies (10). He was maintained postop on conventional ventilation without complications. On hospital day 8, he underwent posterior fusion with instrumentation requiring 2 right-sided chest tubes and 1 on the left. Postop, he was initially returned to his preoperative ventilation settings of SIMV 14, V_{t} 450 mL, PEEP 7 cm H_{2}O, but required 80% FiO_{2}. Peak airway pressures were noted to be over 50 cm H_{2}O; therefore, the ventilator was changed to pressure control assist control rate 14, peak inspiratory pressure (PIP) 38, inspiratory time (IT) 1.5 sec, PEEP 8 cm H_{2}O, mean airway pressure (MAP) 22, and FiO_{2} of 80%. Delivered V_{T} was 450 mL. Five hours postop, a chest x-ray showed a right-sided pneumothorax. The anterior right chest tube was repositioned with resolution of the pneumothorax. As compliance increased, the PIP was weaned to 32 cm H_{2}O with a delivered V_{T} of 480 mL. PIP was continually monitored and adjusted to maintain delivered V_{T} of around 440 mL. Twelve hours postop, the delivered V_{T} and SaO_{2} dropped significantly. A repeat chest x-ray showed a large left pneumothorax requiring a second left-sided chest tube. At this point, he was placed on high frequency ventilation via Sensormedics 3100. Initial settings were FiO_{2} 1.0, amplitude delta p of 80 cm H_{2}O, MAP 30 cm H_{2}O, frequency 7 Hz, and IT 40%. The first arterial blood gas showed a pH 7.28, PCO_{2} 85, PaO_{2} 63, with a correlating TcPCO_{2} of 87. The frequency was decreased to 5 Hz and the IT to 50% to increase minute ventilation. The TcPCO_{2} decreased from 82 to 67. Initial chest x-ray on HFO showed total resolution of the bilateral pneumothoracies with moderate right lower lobe (RLL) consolidation. A bronchoscopy was done on day 3 of HFO ventilation; no mucus plugs were noted. He was then placed with the left side down to aid right lung reexpansion with successful results. For 12 days, he was maintained on HFO, adjusting settings to 3 Hz, delta p 80, MAP 24 cm H_{2}O, 50% IT, and 65% FiO_{2}. In order to remove sedation/paralytic agents and allow spontaneous respiration, he was placed on pressure control AC 48, PIP 28 cm H_{2}O, PEEP 7cm H_{2}O, IT of 0.5 sec and 70% FiO_{2}. He tolerated the transition with acceptable ABGs. He underwent a tracheostomy on postop day 21 to facilitate weaning. His pulmonary mechanics slowly improved, and on postop day 33, he was changed to volume ventilation. Slow, conventional weaning progressed as he improved. On day 89, he was transferred to the general pediatric floor on a 35% trach collar. Discussion: In this case study, we report the successful application of the Sensormedics 3100 in a difficult-to-manage ventilator patient with a restrictive lung component. While the Sensormedics was initially limited to patients under 35 kg, documented cases of successful management over this weight are being reported. Due to the unique pathology, recurrent airleak, and patient's size, we felt this case to be worth reporting.

OF-97-022

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