SESSION TYPE: Critical Care Student/Resident Case Report Posters II
PRESENTED ON: Tuesday, October 23, 2012 at 01:30 PM - 02:30 PM
INTRODUCTION: The current conventional practice of ARDSNet guided vent management strategy does not have any special consideration for morbidly obese patients. These 2 cases show that morbidly obese patients may need significantly more PEEP than we use in our conventional practice.
CASE PRESENTATION: Patient 1: 69 year old vent dependent male with a BMI of 52 transferred to a tertiary hospital for worsening respiratory failure secondary to pseudomonas pneumonia, and renal failure. Hypoxemia worsened despite antibiotics and renal replacement therapy. Despite full vent support with 100% FiO2 and PEEP 22 patient had difficulty in maintaining oxygenation. The ABG at this point was 7.18 PaCo2 59 PaO2 70. An esophageal balloon was inserted to measure trans-pulmonary pressure (PtpPEEP). Initial trans-pulmonary pressure on PEEP of 22 was - 7 cm of H2O. PEEP was titrated up to 32 to achieve a trans-pulmonary pressure of 0 to +1. Twelve hours later, on ventilator setting with higher PEEP of 32, ABG improved to 7.20/58/152. 24 hours latter, pO2 increased to 354 with no significant changes to pH or PaCO2. Despite improvement in PaO2/FiO2, family decided to withdraw life support secondary to patient’s multiple co-morbidities and ventilator dependence. Patient 2: 45 year old female BMI 42 admitted for pneumonia secondary to Influenza and was started on antibiotics and oseltamivir. Patient however became increasing dyspneic with respiratory rate of 45 subsequently requiring intubation and mechanical ventilation. Despite FiO2 90% PEEP 12 patient’s blood gas showed PaO2 54. An esophageal balloon was inserted. Pao2 improved to120 with titration of PEEP to 18 to maintain PtpPEEP between 0 and +1. Over the next 48 hours PEEP was titrated up to 21 cm H2O and FiO2 eventually decreased to 40%. PEEP was later titrated to 10 and patient was extubated successfully on day 4 of mechanical ventilation.
DISCUSSION: With Morbid obesity it is known that decreased external compliance increases intrapleural pressures and creates negative trans-pulmonary pressures. To counter the more negative trans-pulmonary pressure the greater PEEP is needed. The current conventional practice of ARDSNet guided vent management strategy does not have any special consideration for morbidly obese patients. These cases show that morbidly obese patients may need significantly more PEEP than we use in our conventional practice. Esophageal balloon guided measurement of trans-pulmonary pressure in obese patients may be a useful tool in adjusting PEEP to prevent atelectasis and improve oxygenation. It has already been shown that PtpPEEP guided ventilator management has improved oxygenation in general population.
CONCLUSIONS: Patients with ARDS induced refractory hypoxemia and high BMI may specifically benefit from PtpPEEP guided higher PEEP.
1) Talmor D, et al.: N Engl J Med. 2008; 359(20):2095
2) Bernard G: N Engl J Med 2008; 359:2166Acute Respiratory Distress Syndrome Network: N Engl J Med 2000; 342:1301
DISCLOSURE: The following authors have nothing to disclose: Charles Hunley, Rumi Khan, Rakesh Gupta, Timothy Jones, Edgar Jimenez
No Product/Research Disclosure InformationOrlando Health, Orlando, FL