2005 OPEN FORUM Abstracts
HIGH FREQUENCY PERCUSSIVE VENTILATION (HFPV) IN THE MANAGEMENT OF SEVERE PULMONARY CONTUSION AND ABDOMINAL COMPARTMENT SYNDROME - CASE REPORT
Brent Kenney BSRT, RRT, Martin Tyson, DO, Bill Haire RRT. Mercy St. John's Health System, Springfield, MO.
Introduction: Increased intra-abdominal pressure has been demonstrated in patients undergoing large volume fluid resuscitation who are admitted for major trauma, burns, and complex major surgeries. Normal intra-abdominal pressure is zero or may be subatmospheric. Variations occur with body positioning and obesity. Interest has focused on the effects of increased abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) and the effects on the gut, heart, kidneys and lungs. There is lack of agreement on clinical assessment sensitivity and measurement techniques, but bladder pressure is most often used to confirm physical assessment. Elevation of the diaphragm, compression atelectasis, V/Q mismatch, hypoxemia, and increased peak inspiratory pressures represent the effects of IAH and ACS on the lungs. Major trauma patients are at risk for developing Acute Respiratory Distress Syndrome (ARDS). High Frequency Percussive Ventilation with the Percussionaire VDR-4 has been used successfully patients with ARDS. The use of HFPV in ACS is not well documented in the medical literature.
Case Summary: The patient was a 16 y/o male involved in a MVA rollover who was ejected from the car. He sustained a closed head injury, C2 facet fracture, L renal contusions, L renal infarct, liver subcapsular hematoma, L medial malleous fracture, multiple R rib fractures, and extensive bilateral pulmonary contusions. Upon arrival in the Emergency Trauma Center the SpO2 was 83% on FIO2 1.0. Patient was placed on a mechanical ventilator and the first ABG was pH 7.13, PCO2 48, PO2 68 on settings of A/C, VT 700, f 14, FIO2 1.0, Peep 10. Upon arrival to the ICU the patient experienced severe desaturation requiring ACLS protocol for resuscitation including electroshock. Bilateral chest tubes and a pulmonary artery catheter (PAC) were inserted. Initial PAC readings were unremarkable. ABGs after the ACLS protocol and before VDR were pH 6.84, PCO2 110, PO2 60 with P/F ratio 60. The patient was placed on the VDR-4 per Respiratory Care Protocol. Settings were Pulse frequency 500, Convective rate 10, FIO2 1.0, Oscillatory CPAP 10, Proximal airway pressure (PAP) 64 cmH20. ABGs after being placed on the VDR were pH 7.17, PCO2 43, PO2 251 with P/F ratio 251. Over the next 3 hours the patient's SpO2 decreased to the 80s and blood pressure became unstable with tachycardia noted. Pulsatile flowrate on the VDR-4 was increased to maintain oxygenation with mean airway pressure (MAP) > 50 cmH20. Abdominal exploration for ACS was performed in the ICU. Proximal airway pressures dropped from 85 cmH2O to < 60 cmH2O immediately with opening of the abdomen. Slight drop in blood pressure was noted as the patient reperfused his liver and bowel. ABGs after surgery were pH 7.35, PCO2 22, PO2 65 with MAP 33 cmH2O with P/F ratio 65. Twenty four hours later the Proximal Airway Pressure was 42 cmH2O and the MAP was 28 cmH2O with ABGs of pH 7.37, PCO2 36, PO2 149 with P/F ratio 373. The patient was switched to CMV+AF on the Drager Evita 4 after four days. Patient was extubated after 15 days. The abdomen was surgically closed after five days. The patient was discharged to home ambulating with a walker after on day 32.
Conclusion: HFPV with the VDR-4 is a time cycled, pressure limited mode capable of delivering sub physiological tidal volumes at rates of approximately 500 breaths/minute , convective pressure rises at conventional rates and oscillatory/demand CPAP. The Phasitron on the VDR-4 is uniquely designed to change entrainment ratio and delivered VT in response to back pressure in the venturi throat due to increased airway resistance (Raw) and reduced lung compliance (Cdyn). A set pulsatile flow rate against a compressed lung increases PAP. Surgical opening of the abdominal cavity begins reversal of the effect IAH on the diaphragmatic incursion into the thoracic cavity as well as reducing the PAP. HFPV with the VDR-4 was used successfully in this patient with severe bilateral pulmonary contusions and abdominal compartment syndrome.