David Palma, M.D. & George Philips, M.D.
David Palma, M.D.
Former Internal Medicine Resident
Gastroenterology Fellow, University of Florida
George Philips, M.D.
Internal Medicine Resident
gphilips@uab.edu
Hepatology. 2008 Apr;47(4):1257-63.
Oxygen desaturation during sleep in hepatopulmonary syndrome.
Palma DT, Philips GM, Arguedas MR, Harding SM, Fallon MB.
Abstract: Sleep alters respiratory mechanics and gas exchange, which can adversely affect arterial oxygenation. Whether sleep affects oxygenation in hepatopulmonary syndrome is unknown. The aim of this study was to assess oxygen desaturation during sleep in hepatopulmonary syndrome. Twenty adults with cirrhosis including 10 controls and 10 patients with hepatopulmonary syndrome underwent home pulse-oximetry during sleep. Subjects at high risk for obstructive sleep apnea were excluded through the Berlin questionnaire. Subjects who spent more than 10% of total sleep time with arterial oxygen saturation < 90% were classified as sleep-time oxygen desaturators. Sleep-time desaturation was correlated with clinical variables. The results showed that 7 of 10 hepatopulmonary syndrome subjects and none of the 10 controls had sleep-time oxygen desaturation. The median percentage of total sleep time with arterial oxygen saturation < 90% was significantly higher in hepatopulmonary syndrome subjects than in controls (medians 25% versus 0%, P = 0.005). Hepatopulmonary syndrome subjects had significantly lower wake-time arterial oxygen saturation level (median, 97% versus 95%; P = 0.003) and mean sleep-time arterial oxygen saturation level (median, 96% versus 91%; P = 0.0008) than did the controls. Sleep-time desaturation directly correlated with alveolar-arterial oxygen gradient (P = 0.0007) and inversely correlated with wake-time arterial oxygen tension (P = 0.0007) and oxygen saturation (P < 0.0001). Conclusion: Oxygen desaturation occurred during sleep in 70% of hepatopulmonary syndrome subjects, the degree of which correlated with the severity of hepatopulmonary syndrome. Marked hypoxemia during sleep may occur in hepatopulmonary syndrome patients who, according to wake-time oxygen values, have only mild to moderate hypoxemia.
Biography
David Palma graduated from medical school at SUNY Syracuse in 2004. He completed residency training in internal medicine at UAB in 2007. He has since been a fellow in gastroenterology at the University of Florida. His current research focus is in the area of non-alcoholic fatty liver disease (NAFLD). He also has a particular clinical interest in gastrointestinal infections endemic in the tropics, and the application of gastroenterology to the developing world.
George Philips received his B.S. with honors from Pennylvania State University in 2002 and M.D. from University of Rochester School of Medicine in 2006. He is currently completing his Internal Medicine training at the University of Alabama at Birmingham. He served under the guidance of his mentor Dr. Michael Fallon alongside fellow resident Dr. Palma on nocturnal desaturation in hepatopulmonary syndrome. He has extended his research to other areas including potential medical therapies for hepatopulmonary syndrome. After completion of internal medicine residency he plans to continue his research training in Gastroenterology & Hepatology at Duke University.
Research Interests
Dr. Fallon’s major investigative focus is understanding the pathogenesis and clinical features of pulmonary vascular complications of chronic liver disease. His approach involves both translational studies based on animal models and a multicenter clinical study group. Translational studies are funded through an R01, the Regional American Heart Association and a VA Merit Review award. Our multicenter "Pulmonary Vascular Complications of Liver Disease" group includes 7 transplant programs across the U.S. and is currently funded by two R03 awards, one to UAB and one to Columbia University. He also has ongoing collaborations within UAB with the Vascular Biology/Hypertension Program, Center for Free Radical Biology, Gene Therapy Center, Cell Adhesion and Matrix Research Center, Pharmacology Department and with Liver Transplant program. Outside collaborations include the 6 participating transplant centers, the Cholangiocyte Biology program at Texas A&M University, the Vascular Biology program at the Medical College of Georgia, the Pulmonary Vascular Biology Program at The University of Colorado, and the Physiology Department at the University of South Alabama.
