title: The relation of near-infrared spectroscopy with changes in peripheral circulation in critically ill patients.
abstract: OBJECTIVE
  We conducted this observational study to investigate tissue oxygen saturation during a vascular occlusion test in relationship with the condition of peripheral circulation and outcome in critically ill patients.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Multidisciplinary intensive care unit in a university hospital.
  
  
  METHODS
  Seventy-three critically ill adult patients admitted to the intensive care unit.
  
  
  METHODS
  None.
  
  
  RESULTS
  Patients were followed every 24 hrs until day 3 after intensive care admission. Near-infrared spectroscopy was used to measure thenar tissue oxygen saturation, tissue oxygen saturation deoxygenation rate, and tissue oxygen saturation recovery rate after the vascular occlusion test. Measurements included heart rate, mean arterial pressure, forearm-to-fingertip skin-temperature gradient, and physical examination of peripheral perfusion with capillary refill time. Patients were stratified according to the condition of peripheral circulation (abnormal: forearm-to-fingertip skin-temperature gradient ≥4 and capillary refill time >4.5 secs). The outcome was defined based on the daily Sequential Organ Failure Assessment score and blood lactate levels. Upon intensive care unit admission, 35 (47.9%) patients had abnormal peripheral perfusion (forearm-to-fingertip skin-temperature gradient >4 or capillary refill time >4.5 secs). With the exception of the tissue oxygen saturation deoxygenation rate, tissue oxygen saturation baseline and tissue oxygen saturation recovery rate were statistically lower in patients who exhibited abnormal peripheral perfusion than in those with normal peripheral perfusion: 72 ± 9 vs. 81 ± 9; p = .001 and 1.9 ± 0.7 vs. 3.2 ± 0.9; p = .001, respectively. When a mixed-model analysis was performed over time for estimate (s) calculation, adjusted to the condition of disease, we did not find a significant clinical effect between vascular occlusion test-derived tissue oxygen saturation measurements (as response variables) and mean systemic hemodynamic variables (as independent variables): tissue oxygen saturation vs. heart rate: s (95% confidence interval) = 0.007 (-0.08; 0.09); tissue oxygen saturation vs. mean arterial pressure: s (95% confidence interval) = -0.02 (-0.12; 0.08); tissue oxygen saturation deoxygenation rate vs. heart rate: s (95% confidence interval) = 0.002 (-0.0004; 0.006); tissue oxygen saturation deoxygenation rate vs. mean arterial pressure: s (95% confidence interval) - 0.0007 (-0.003; 0.004); tissue oxygen saturation recovery rate vs. heart rate: s (95% confidence interval) = -0.009 (-0.02; -0.0015); tissue oxygen saturation recovery rate vs. mean arterial pressure: s (95% confidence interval) = 0.01 (0.002; 0.018). However, there was a strong association between tissue oxygen saturation baseline and tissue oxygen saturation recovery rate with abnormal peripheral perfusion: tissue oxygen saturation vs. abnormal peripheral perfusion: s (95% confidence interval) = -10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) =-10.1 (-13.9; -6.2); tissue oxygen saturation recovery rate vs. abnormal peripheral perfusion: s (95% confidence interval) = -1.1 (-1.4; -0.81). Poor outcome was more closely related to abnormalities in peripheral perfusion than to tissue oxygen saturation-derived parameters.
  
  
  CONCLUSIONS
  We found that the condition of peripheral circulation in critically ill patients strongly influences tissue oxygen saturation resting values and the tissue oxygen saturation reoxygenation rate but not the tissue oxygen saturation deoxygenation rate. In addition, changes in near-infrared spectroscopy-derived variables were independent of condition of disease and were not accompanied by any major differences in systemic hemodynamic variables.
authors.affiliation: Department of Intensive Care Adults, Erasmus MC University Hospital Rotterdam, Rotterdam, The Netherlands.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lima
authors.forename: Jasper
authors.initials: J
authors.lastname: van Bommel
authors.forename: Karolina
authors.initials: K
authors.lastname: Sikorska
authors.forename: Michel
authors.initials: M
authors.lastname: van Genderen
authors.forename: Eva
authors.initials: E
authors.lastname: Klijn
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Lesaffre
authors.forename: Can
authors.initials: C
authors.lastname: Ince
authors.forename: Jan
authors.initials: J
authors.lastname: Bakker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001785:Blood Gas Monitoring, Transcutaneous / Q000379:methods; D016638:Critical Illness; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008663:Metacarpus / Q000502:physiology; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology*; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000502:physiology*; D012772:Shock, Septic / Q000097:blood / Q000503:physiopathology*; D012881:Skin Temperature / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010100:Oxygen