Tissue oxygenation and perfusion in patients with systemic sepsis.
OBJECTIVE
Multiple organ dysfunction is associated with systemic sepsis. To investigate whether this is attributable to peripheral tissue hypoperfusion and/or cellular hypoxia, simultaneous measurements of tissue perfusion and oxygenation were made in patients with severe sepsis and in controls.


METHODS
Prospective, observational study.


METHODS
Adult intensive care unit, tertiary referral center.


METHODS
Volunteers (group C, n = 7), patients undergoing cardiopulmonary bypass (group B, n = 6), and patients with severe sepsis (group S, n = 6).


METHODS
Limb ischemia and reperfusion.


RESULTS
Tissue oxygenation and microvascular flow were measured by using microelectrodes inserted into brachoradialis muscle and overlying subcutaneous tissue. Forearm cutaneous red cell flux and regional blood flow were measured simultaneously. Responses to 20 mins of limb ischemia and subsequent reperfusion were observed. Baseline muscle tissue oxygenation was greater in sepsis (1.7 +/- 0.2, 1.5 +/- 0.7, and 4.4 +/- 0.6 kPa for groups C, B, and S, respectively, mean +/- sem, p <.05), although baseline subcutaneous tissue oxygenation did not vary between groups. During ischemia tissue oxygenation, values decreased in muscle (to 1.3 +/- 0.2, 1.0 +/- 0.4, and 1.5 +/- 0.4 kPa for groups C, B, and S, respectively) and subcutaneous tissue (to 2.0 +/- 0.3, 1.7 +/- 0.5, and 2.3 +/- 0.2 kPa for groups C, B, and S, respectively). Decline in tissue oxygen tension was initially more rapid in septic muscle compared with controls (25% decrease, 68 +/- 23 vs. 176 +/- 38 for group S vs. group C, p <.05, and 50% decrease, 126 +/- 34 vs. 398 +/- 72 secs for group S vs. group C, p <.01). However, overall rate of tissue decline was similar (95% decrease, 444 +/- 122 vs. 614 +/- 96 for group S vs. group C, p >.05). After reperfusion, significant differences in muscle tissue oxygenation reappeared between groups (2.0 +/- 0.3, 1.5 +/- 0.7, and 4.0 +/- 0.4 kPa for groups C, B, and S, respectively, p <.05). There were no differences in time to 25%, 50%, or 95% tissue oxygen recovery. Whole limb reperfusion was significantly less in patient groups compared with controls (10.6 +/- 0.9, 4.5 +/- 1.2, and 4.3 +/- 1.6 mL x 100 mL(-1) x min(-1) for groups C, B, and S, respectively, p <.05).


CONCLUSIONS
Significant differences in tissue oxygenation distribution between muscle and subcutaneous tissues occur in patients with severe sepsis. High baseline muscle tissue oxygen levels are accompanied by rapid extraction of oxygen during stagnant ischemia.
Sair
M
M
Unit of Critical Care, Imperial College School of Medicine and Royal Brompton Hospital, London, UK.
Etherington
P J
PJ
Peter Winlove
C
C
Evans
T W
TW
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D005542:Forearm / Q000098:blood supply; D006439:Hemodynamics; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation; D008839:Microelectrodes; D008875:Middle Aged; D009102:Multiple Organ Failure / Q000503:physiopathology*; D010100:Oxygen / Q000378:metabolism*; D010991:Plethysmography; D011446:Prospective Studies; D012039:Regional Blood Flow; D018805:Sepsis / Q000503:physiopathology*; D018709:Statistics, Nonparametric
D010100:Oxygen