title: Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.
abstract: BACKGROUND
  Patients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism.
  
  
  METHODS
  Ten consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter.
  
  
  RESULTS
  At 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31+/-10 vs. 49+/-12%, p<0.0001; 86+/-12 vs. 105+/-17 mmHg, p<0.01; 1.5+/-0.4 vs. 1.9+/-0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonary-artery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29+/-10 vs. 21+/-12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=-0.855, p<0.001).
  
  
  CONCLUSIONS
  In obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.
authors.affiliation: Department for Intensive Internal Medicine, General Hospital Celje, Slovenia.
authors.forename: Bojan
authors.initials: B
authors.lastname: Krivec
authors.forename: Gorazd
authors.initials: G
authors.lastname: Voga
authors.forename: Matej
authors.initials: M
authors.lastname: Podbregar
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D003422:Critical Care; D005260:Female; D005440:Fluid Therapy; D006439:Hemodynamics; D006493:Heparin / Q000008:administration & dosage*; D017052:Hospital Mortality; D006801:Humans; D007261:Infusions, Intra-Arterial; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood*; D010102:Oxygen Inhalation Therapy; D011379:Prognosis; D011651:Pulmonary Artery; D011655:Pulmonary Embolism / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D012769:Shock / Q000188:drug therapy* / Q000401:mortality / Q000503:physiopathology; D015996:Survival Rate; D015912:Thrombolytic Therapy; D014568:Urokinase-Type Plasminogen Activator / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D006493:Heparin; D014568:Urokinase-Type Plasminogen Activator; D010100:Oxygen