2002 OPEN FORUM Abstracts
ADULT HIGH FREQUENCY OSCILLATORY VENTILATION (HFOV): UTILITY IN PATIENTS WITH LARGE BODY MASS INDEX (BMI).
S. Bagwell, MD; David Kissin, RRT; Department of Critical Care, Maine Medical Center, Portland, Maine.
High frequency oscillatory ventilation (HFOV) is a proven modality in the pediatric population. Trials are now underway to prove efficacy of the oscillator for the adult patient with adult respiratory distress syndrome (ARDS). We successfully oscillated two women weighing 138 and 144 kg respectively with a diagnosis of ARDS on SensorMedics 3100B oscillator.
Case 1: 35 y.o. white female, weighing 138 kg, BMI 54, presented to the ED with complaints of chest pain and dyspnea after a 10-day prodrome of upper respiratory tract symptoms. Initial evaluation revealed a complicated parapneumonic effusion. Because of extensive loculations, she was taken to the operating room for thoracoscopy and lysis of adhesions. During the surgical procedure, she became extremely difficult to oxygenate and ventilate, OI > 80, and was placed on SensorMedics 3100A HFOV; Æ P 90, Paw 40, 100% FIO2, 3 Hz, Ti 33%, flow 35 Lpm, and power 10. CXR was compatible with ARDS. Initial ABG obtained on HFOV showed, pH 7.14, PCO2 62, HCO3 21, PO2 63 She was changed to SensorMedics 3100B; Æ P 80, Paw 38, 100% FIO2, Hz 3, Ti 33%, and power 5.5. The patient stabilized and the FIO2 was quickly weaned to 55%. She remained on HFOV for 4 days, was then weaned to conventional ventilation. She was discharge to a rehabilitation hospital on day 162 without the need for oxygen.
Case 2: 42 y.o. white female, weighing 144 kg, BMI 58.5, was admitted after a motor vehicle accident, which resulted in long bone fractures, and significant chest and facial trauma. ARDS developed on day 18 secondary to staphylococcal sepsis. Multiple manipulations with conventional ventilation and prone positioning failed to provide oxygenation, OI 62. The patient was placed on 3100A; Æ P 73, Paw 45, FIO2 100%, 5 Hz, Ti 33%, flow 37 Lpm, power 10. OI 52. Oxygenation improved, but ventilation was difficult despite manipulations of Hz, cuff leak, and Ti. The patient was then placed on the 3100B; Æ P 64, Paw 33, FIO2 53%, 5 Hz, Ti 50%, 28 lpm flow, power 4.5. Oxygenation and ventilation were achieved without difficulty. She remained on HFOV for 18 days and was eventually discharged home without respiratory symptoms. These two very large adult patients with BMI greater than 54 failed conventional ventilation, from both oxygenation as well as a ventilation perspective, despite multiple manipulations. There were well oxygenated but were not able to be ventilated with model 3100A SensorMedics HFOV. Both patients were adequately ventilated with the model 3100B with titration of Ti, and HZ, without the need for cuff leak. This was felt to be due to larger tidal volumes delivered for a given Æ P and an increase in available bias flow. Major problems encountered and solved included: overheating of the driver resulting in a lowered effective Æ P and maintenance of alveolar volume during suctioning and hospital generator testing. Hemodynamics, including oxygen delivery, actually improved with the use of HFOV.