title: Detection of microcirculatory impairment by transcutaneous oxymetry monitoring during hemodialysis: an observational study.
abstract: BACKGROUND
  Little is known about the effects of intermittent hemodialysis on microcirculatory perfusion. The aim of this study is to assess the effects of hemodialysis on microvascular perfusion using transcutaneous oxymetry (TCPO2).
  
  
  METHODS
  In this observational study, hourly TCPO2 measurements were performed during hemodialysis sessions. Ankle brachial index (ABI) was carried out to classify patients according their vascular condition.
  
  
  RESULTS
  50 patients (mean age 70 ± 8 years old) were enrolled. Mean TCPO2 decreased significantly on average 23.9% between start and finish of hemodialysis. Severe ischemia (TCPO2 < 30 mmHg) and critical ischemia (TCPO2 < 10 mmHg) occurred during dialysis in 47.1% and 15.5% respectively. Critical ischemia occurred only in limbs with ABI < 0.9 (8.3%) or > 1.3 (28%). Patients with critical ischemia experienced a significantly larger decline in mean blood pressure (32.4 ± 26.1 mmHg vs 12.7 ± 10.7 mmHg; P = 0.007) and a more pronounced ultrafiltration (45.55 ± 16.9 ml/kg vs 35.17 ± 18.2 ml/kg; P = 0.04) compared to patients without ischemia. Clinical outcomes (death or vascular procedures) were five times more frequent in patients who had developed critical ischemia (55.7% vs 10.1% P = 0.01). The elevated age of patients, the low basal value of TCPO2, and the occurrence of critical ischemia were more frequently associated with clinical outcome (P = 0.03, P = 0.048, P = 0.01 respectively).
  
  
  CONCLUSIONS
  This study demonstrates that hemodialysis induces microcirculatory injury, dependent on blood pressure reduction, peripheral vascular state and ultrafiltration. The occurrence of critical ischemia is associated to pejorative patient outcome and therefore, TCPO2 seems to be useful to avoid potential distal tissue damage during hemodialysis.
authors.affiliation: Department of Internal Medicine, Rouen University Hospital, 1 Rue de Germont, 76031 Rouen, France. ygal.benhamou@chu-rouen.fr.
authors.forename: Ygal
authors.initials: Y
authors.lastname: Benhamou
authors.forename: Loic
authors.initials: L
authors.lastname: Begarin
authors.forename: Nathalie
authors.initials: N
authors.lastname: David
authors.forename: Nicole
authors.initials: N
authors.lastname: Cailleux
authors.forename: Catherine
authors.initials: C
authors.lastname: Bessin
authors.forename: Herve
authors.initials: H
authors.lastname: Lévesque
authors.forename: Stephane
authors.initials: S
authors.lastname: Edet
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D006801:Humans; D008297:Male; D008833:Microcirculation; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D058729:Peripheral Arterial Disease / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010100:Oxygen