title: Swimming-Induced Pulmonary Edema: Pathophysiology and Risk Reduction With Sildenafil.
abstract: BACKGROUND
  Swimming-induced pulmonary edema (SIPE) occurs during swimming or scuba diving, often in young individuals with no predisposing conditions, and its pathophysiology is poorly understood. This study tested the hypothesis that pulmonary artery and pulmonary artery wedge pressures are higher in SIPE-susceptible individuals during submerged exercise than in the general population and are reduced by sildenafil.
  
  
  RESULTS
  Ten study subjects with a history of SIPE (mean age, 41.6 years) and 20 control subjects (mean age, 36.2 years) were instrumented with radial artery and pulmonary artery catheters and performed moderate cycle ergometer exercise for 6 to 7 minutes while submersed in 20°C water. SIPE-susceptible subjects repeated the exercise 150 minutes after oral administration of 50 mg sildenafil. Work rate and mean arterial pressure during exercise were similar in controls and SIPE-susceptible subjects. Average o2 and cardiac output in controls and SIPE-susceptible subjects were: o2 2.42 L·min(-1) versus 1.95 L·min(-1), P=0.2; and cardiac output 17.9 L·min(-1) versus 13.8 L·min(-1), P=0.01. Accounting for differences in cardiac output between groups, mean pulmonary artery pressure at cardiac output=13.8 L·min(-1) was 22.5 mm Hg in controls versus 34.0 mm Hg in SIPE-susceptible subjects (P=0.004), and the corresponding pulmonary artery wedge pressure was 11.0 mm Hg versus 18.8 mm Hg (P=0.028). After sildenafil, there were no statistically significant differences in mean pulmonary artery pressure or pulmonary artery wedge pressure between SIPE-susceptible subjects and controls.
  
  
  CONCLUSIONS
  These observations confirm that SIPE is a form of hemodynamic pulmonary edema. The reduction in pulmonary vascular pressures after sildenafil with no adverse effect on exercise hemodynamics suggests that it may be useful in SIPE prevention.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00815646.
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.). richard.moon@duke.edu.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Moon
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Stefanie D
authors.initials: SD
authors.lastname: Martina
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Dionne F
authors.initials: DF
authors.lastname: Peacher
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Jennifer F
authors.initials: JF
authors.lastname: Potter
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Tracy E
authors.initials: TE
authors.lastname: Wester
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Anne D
authors.initials: AD
authors.lastname: Cherry
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Natoli
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Claire E
authors.initials: CE
authors.lastname: Otteni
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: Dawn N
authors.initials: DN
authors.lastname: Kernagis
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: William D
authors.initials: WD
authors.lastname: White
authors.affiliation: From Department of Anesthesiology, and Center for Hyperbaric Medicine & Environmental Physiology, Duke University Medical Center, Durham, NC (R.E.M., S.D.M., D.F.P., J.F.P., T.E.W., A.D.C., M.J.N., C.E.O., D.N.K., W.D.W., J.J.F.); Department of Medicine, Duke University Medical Center, Durham, NC (R.E.M.); Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia (D.F.P.); Department of Anesthesiology, University of Virginia, Charlottesville (J.F.P.); Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, Charleston (T.E.W.); Delaware County Memorial Hospital, Drexel Hill, PA (C.E.O.); and Institute for Human & Machine Cognition, Pensacola, FL (D.N.K.).
authors.forename: John J
authors.initials: JJ
authors.lastname: Freiberger
mesh_terms: D000328:Adult; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology; D003080:Cold Temperature / Q000009:adverse effects; D005080:Exercise Test / Q000187:drug effects / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011654:Pulmonary Edema / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D011669:Pulmonary Wedge Pressure / Q000187:drug effects / Q000502:physiology; D040242:Risk Reduction Behavior; D000068677:Sildenafil Citrate / Q000494:pharmacology / Q000627:therapeutic use*; D013550:Swimming / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D014665:Vasodilator Agents; D000068677:Sildenafil Citrate
keywords: diving; hemodynamics; immersion; pulmonary circulation; pulmonary edema; swimming