Subcutaneous Tissue Oxygen Research Articles

Effect of oral hydration on skin microcirculation in healthy young and midlife and older adults

Clinically undetected underhydration lowers subcutaneous tissue oxygen, impairs healing and increases wound infection. This study examined the effect of supplemental oral hydration on noninvasive measures of skin temperature (T(s)), transcutaneous skin O(2) (PtcO(2)), and CO(2) (PtcCO(2)), and skin blood flow (laser Doppler fluxmetry [Flux]=concentration of moving blood cells [CMBC] x Velocity) in healthy adults. Nineteen Control and 18 Test (Hydrated) subjects participated. Ad libitum fluid intake was allowed before the experiment. Sensors were placed on the chest, lower legs, and feet. Time 1 resting supine T(s), PtcO(2)/PtcCO(2), and Flux/CMBC/Velocity were obtained. Then, the Test group ingested 500 mL of H(2)O. Time 2 measures were obtained 30 minutes later. Data were analyzed using ANOVA. Change in T(s), PtcO(2), PtcCO(2), and Velocity did not differ between groups. Flux increased more in the Test than in the Control group (p<0.01). The Flux change was explained by a CMBC increase (p<0.05). For midlife/older subjects only, the CMBC change was greater in the Test than in the Control group (p<0.01). Flux may be sufficiently sensitive to detect microvascular changes in response to supplemental oral hydration. These data also suggest that subtle levels of hypoperfusion due to underhydration may exist in community-dwelling healthy midlife/older adults in their natural state.

Laparoscopic surgery impairs tissue oxygen tension more than open surgery

Wound infection remains a common and serious complication after colonic surgery. Although many colonic operations are performed laparoscopically, it remains unclear whether this has any impact on the incidence of wound infection. Subcutaneous tissue oxygenation is an excellent predictor of surgical wound infection. The impact of open and laparoscopic colonic surgery on tissue oxygenation was compared. Fifty-two patients undergoing elective open and laparoscopic left-sided colonic resections were evaluated in a prospective observational study. Anaesthesia management was standardized and intraoperative arterial partial pressure of oxygen was kept at 150 mmHg in both groups. Oxygen tension was measured in the subcutaneous tissue of the right upper arm. At the start of surgery subcutaneous tissue oxygen tension (PsqO(2)) was similar in both groups (mean(s.d.) 65.8(17.2) and 63.7(23.6) mmHg for open and laparoscopic operations respectively; P = 0.714). Tissue oxygen remained stable in the open group, but dropped significantly in the laparoscopic group during the course of surgery (PsqO(2) after operation 53.4(12.9) and 45.5(11.6) mmHg, respectively; P = 0.012). Laparoscopic colonic surgery significantly decreases PsqO(2), an effect that occurs early in the course of surgery. As tissue oxygen tension is a predictor of wound infection, these results may explain why the risk of wound infection after laparoscopic surgery remains higher than expected.

Instructions for Obtaining Journal CME Credit

Anesthesiology's journal-based CME program is open to all readers. Members of the American Society of Anesthesiologists participate at a preferred rate, but you need not be an ASA member or a journal subscriber to take part in this CME activity. Please complete the following steps:The American Society of Anesthesiologists is approved by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing medical education programs for physicians.The American Society of Anesthesiologists designates this educational activity for a maximum of 1 AMA PRA Category 1 Credit ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.Purpose: The focus of the journal-based CME program, and the articles chosen for the program, is to educate readers on current developments in the science and clinical practice of the specialty of Anesthesiology.Target Audience: Physicians and other medical professionals whose medical specialty is the practice of anesthesia.Learning Objectives: After reading this article, participants should have a better understanding of some of the factors contributing to surgical site infections and what anesthesiologists can do to reduce this complication.Authors –William J. Mauermann, M.D., and Edward C. Nemergut, M.D. Grants or research support: None Consultantships or honoraria: None The article authored by Drs. Mauermann and Nemergut was supported solely from institutional and/or departmental sources.Question Writer –Peter L. Bailey, M.D. Dr. Bailey has no grants, research support, or consultant positions, nor does he receive any honoraria from outside sources, which may create conflicts of interest concerning this CME program.Based on the article by Mauermann and Nemergut entitled “The anesthesiologist's role in the prevention of surgical site infections”http://content.wkhealth.com/linkback/openurl/trusted?issn=0003-3022&amp;volume=105&amp;issue=2&amp;spage=413&amp;part=fulltextin the August issue of Anesthesiology, choose the one correct answer for each question:1. Which of the following statements concerning surgical site infections is most likely true?A. They account for the vast majority of all hospital-acquired infections.B. They become established within a few hours of contamination.C. They typically present later than 48 hours after surgery.D. They are not related to surgical technique.2. Compared to normothermia (37 ± 0.3 °C), mild perioperative hypothermia (34–36 °C) is most likely to be associated withA. A decrease in cardiac complicationsB. Improved intraoperative hemostasisC. An increase in surgical site infectionsD. Shorter hospital length of stay3. Compared to normothermia (37 ± 0.3 °C), mild perioperative hypothermia (34–36 °C) is associated with all of the following except A. A greater degree of subcutaneous tissue vasoconstrictionB. Delayed postoperative food intakeC. A greater incidence of surgical site infectionsD. Earlier collagen deposition in surgical wounds4. Which of the following statements is most likely true?A. Decreased subcutaneous tissue oxygen tensions are associated with surgical site infections.B. Hypothermia enhances the killing of bacteria by neutrophils.C. Hypothermia decreases nitrogen loss.D. Subcutaneous tissue oxygen requirements are high.5. Which of the following statements concerning glucose and the risk for surgical site infections is most likely true?A. Hyperglycemia increases surgical site infections only in diabetic patients.B. Hyperglycemia decreases immune defense mechanisms against infection.C. Keeping glucose levels less than 250 mg/dl eliminates the increased risk of infection associated with hyperglycemia.D. Hyperglycemia is not associated with an increase in mortality in hospitalized patients.6. Which of the following statements concerning preoperative antibiotic prophylaxis for surgical site infections is most likely true?A. Prophylaxis should target as many pathogens as possible.B. Prophylaxis with a cephalosporin is not adequate for surgery requiring gram-negative and anaerobic coverage.C. Patients reporting any reaction to penicillin should not receive a cephalosporin.D. The most effective time for antibiotic administration is within 1 hour prior to skin incision.

Subcutaneous tissue oxygenation is markedly low during the postoperative period in patients undergoing cardiac bypass surgery

Cardio-Thoracic and Vascular Anesthesiology and Intens, General Hospital of Vienna, Vienna, Germany

Correlation between arterial and subcutaneous tissue oxygenation in lean and obese volunteers

Correlation between arterial and subcutaneous tissue oxygenation in lean and obese volunteers

Tissue oxygenation response to mild hypercapnia during cardiopulmonary bypass with constant pump output

Tissue oxygenation is the primary determinant of wound infection risk. Mild hypercapnia markedly improves cutaneous, subcutaneous (s.c.), and muscular tissue oxygenation in volunteers and patients. However, relative contributions of increased cardiac output and peripheral vasodilation to this response remains unknown. We thus tested the hypothesis that increased cardiac output is the dominant mechanism. We recruited 10 ASA III patients, aged 40-65 yr, undergoing cardiopulmonary bypass for this crossover trial. After induction of anaesthesia, a Silastic tonometer was inserted s.c. in the upper arm. S.C. tissue oxygen tension was measured with both polarographic electrode and fluorescence-based systems. Oximeter probes were placed bilaterally on the forehead to monitor cerebral oxygenation. After initiation of cardiopulmonary bypass, in random order patients were exposed to two arterial CO(2) partial pressures for 30 min each: 35 (normocapnia) or 50 mm Hg (hypercapnia). Bypass pump flow was kept constant throughout the measurement periods. Hypercapnia during bypass had essentially no effect on Pa(CO(2)) , mean arterial pressure, or tissue temperature. Pa(CO(2)) and pH differed significantly. S.C. tissue oxygenation was virtually identical during the two Pa(CO(2)) periods [139 (50-163) vs 145 (38-158), P=0.335] [median (range)]. In contrast, cerebral oxygen saturation (our positive control measurement) was significantly less during normocapnia [57 (28-67)%] than hypercapnia [64 (37-89)%, P=0.025]. Mild hypercapnia, which normally markedly increases tissue oxygenation, did not do so during cardiopulmonary bypass with fixed pump output. This suggests that hypercapnia normally increases tissue oxygenation by increasing cardiac output rather than direct dilation of peripheral vessels.

Continuous intraoperative opioid administration increases subcutaneous tissue oxygen tension

Continuous intraoperative opioid administration increases subcutaneous tissue oxygen tension

Mild Hypercapnia Increases Subcutaneous and Colonic Oxygen Tension in Patients Given 80% Inspired Oxygen during Abdominal Surgery

Supplemental perioperative oxygen increases tissue oxygen tension and decreases incidence of wound infection in colorectal surgery patients. Mild intraoperative hypercapnia also increases subcutaneous tissue oxygen tension. However, the effect of hypercapnia in patients already receiving supplemental oxygen is unknown, as is the effect of mild hypercapnia on intestinal oxygenation in humans-although the intestines are presumably the tissue of interest for colon surgeries. The authors tested the hypothesis that mild intraoperative hypercapnia increases both subcutaneous tissue and intramural intestinal oxygen tension in patients given supplemental oxygen. Patients undergoing elective colon resection were randomly assigned to normocapnia (n = 15, end-tidal carbon dioxide tension 35 mmHg) or mild hypercapnia (n = 15, end-tidal carbon dioxide tension 50 mmHg). Intraoperative inspired oxygen concentration was 80%. The authors measured subcutaneous tissue oxygen tension in the right upper arm and intramural oxygen tension in the left colon. Measurements were averaged over time within each patient and, subsequently, among patients. Data were compared with chi-square, unpaired t, or Mann-Whitney rank sum tests; P < 0.05 was significant. Morphometric characteristics and other possible confounding factors were similar in the groups. Intraoperative tissue oxygen tension in hypercapnic patients was significantly greater in the arm (mean +/- SD: 116 +/- 29 mmHg vs. 84 +/- 25 mmHg; P = 0.006) and colon (median [interquartile range]: 107 [81-129] vs. 53 [41-104] mmHg; P = 0.020). During supplemental oxygen administration, mild intraoperative hypercapnia increased tissue oxygen tension in the arm and colon. Previous work suggests that improved tissue oxygenation will reduce infection risk via the proposed pathomechanism, although only an outcome study can confirm this.

Optimal perioperative oxygen administration

During anesthesia and surgery oxygen is routinely administered to all patients. Inspired oxygen concentrations, however, vary between 30 and 100%, and oxygen is often administered in a seemingly random manner. During the last decade it has been shown in several randomized trials that perioperative supplemental oxygen administration might improve outcome after certain surgical procedures. The purpose of this review is to provide an overview about the benefits and risks of supplemental oxygen administration in the perioperative period. Supplemental oxygen improves immune function. Furthermore, 80% inspired oxygen fraction almost doubles subcutaneous tissue oxygen tension and halves the rate of postoperative wound infections. Some studies have shown that supplemental oxygen also decreases the rate of postoperative nausea and vomiting after laparoscopic and open abdominal surgical procedures. Preconditioning with oxygen might improve organ function after liver transplantation and outcome after spinal ischemic insults. Supplemental perioperative oxygen administration is not associated with clinically important side effects. Supplemental oxygen administration during the perioperative period might be a simple, inexpensive and well-tolerated treatment option to improve patient outcome. The optimal inspired oxygen concentration still needs to be evaluated.

Perflubron emulsion increases subcutaneous tissue oxygen tension in rats

ABSTRACTOxygen plays a central role in wound healing. The hypothesis of this study was that the administration of a perfluorocarbon emulsion, which dissolves oxygen will increase subcutaneous tissue oxygen tension (PsqO2) in normovolemic and hemorrhaged animals. In the first set of experiments, PsqO2 was measured with a polarographic oxygen electrode along the dorsum of normovolemic‐anesthetized rats (n=20) breathing supplemental oxygen. After baseline equilibration of tissue oxygen tension, perflubron emulsion (n=12) or saline control (n=8) was administered. Perflubron administration increased PsqO2 by 32.0 ± 7.2 mmHg, whereas saline administration had no effect (−1.0 ± 6.6 mmHg). In a second set of experiments, PsqO2 (n=12) was measured in rats breathing 100 percent oxygen after being bled 20 percent of their blood volume. Creating hypovolemic rats allowed for the study of the effect of perflubron emulsion administration on subcutaneous oxygen tension in tissues with compromised blood flow. Perflubron emulsion was only effective at increasing oxygen tension in tissues with oxygen extractions less then 2.0 vol%. These findings agree with those results analytically predicted based on the oxygen solubility of the perflubron emulsion.

Urapidil enhances subcutaneous tissue oxygen tension during convective rewarming of mildly hypothermic rats

To investigate whether urapidil ( α 1-adrenergic antagonist/5-HT 1A agonist) enhances subcutaneous tissue oxygen tension (P sqO 2) during convective rewarming, we performed a prospective, randomized, placebo-controlled animal study. Mild hypothermia was achieved by surface cooling. Protocol A: before rewarming : i.v. bolus of 1.0 ml NaCl 0.9%/kg body weight; Protocol B: before rewarming: i.v. bolus of 5 mg urapidil/kg body weight. Urapidil significantly reduced the rewarming time (placebo: 30.2±2.9 min, urapidil: 24.2±2.3 min, P = 0.0 1 2 ) and the P sqO 2 during rewarming was significantly enhanced ( P = 0.0 2 3 , AUC P sq O 2 ‐ placebo versus AUC P sq O 2 ‐ urapidil ). The α 1-adrenergic antagonist/5-HT 1A agonist urapidil accelerates convective rewarming and enhances P sqO 2 during rewarming in mildly hypothermic rats. Obviously, urapidil therapy increased the shift of heat from the periphery to the core. It is known that 5-HT 1A receptor agonists reduce thermoregulatory thresholds to cold. Therefore, a reduction in oxygen consumption with an increased oxygen delivery to subcutaneous tissues by urapidil is a further possible mechanism.

Evaluation of tissue oximetry in perioperative monitoring of colorectal surgery.

Twenty patients undergoing elective colorectal surgery were studied during and after operation by means of tissue oximetry measuring the subcutaneous partial pressure of oxygen (PscO2) and by gastric intramural pH measurement. Mean(s.d.) PscO2 recorded 24 h after surgery was significantly lower than the peroperative value: 14(10) versus 24(14) mmHg, P less than 0.02. The postoperative PscO2 was also significantly lower than that measured in a control group of ten healthy volunteers: 14(10) versus 34(18) mmHg, P less than 0.001. The peroperative PscO2 of the patients who developed a postoperative complication was significantly lower than that of those who had an uneventful postoperative clinical outcome: 16(9) versus 32(14) mmHg, P less than 0.02. The peroperative PscO2 of the patient group with complications was also significantly lower than that of the control group: 16(9) versus 34(18) mmHg, P less than 0.02. The peroperative PscO2 of the group of patients without complications was almost identical to that of the control group. During operation only one patient developed gastric intramural acidosis. Perioperative oxygen debt and the response of subcutaneous tissue oxygen tension to oxygen breathing seemed to correlate better with clinical outcome than gastric wall pH values and the conventional parameters of tissue perfusion.

Tissue Oxygenation in Obese and Non-obese Patients During Laparoscopy

Wound infection risk is inversely related to subcutaneous tissue oxygenation, which is reduced in obese patients and may be reduced even more during laparoscopic procedures. We evaluated subcutaneous tissue oxygenation (PsqO(2)) in 20 patients with a body mass index (BMI) > or=40 kg/m(2) (obese group) and 15 patients with BMI <30 kg/m(2) (non-obese group) undergoing laparoscopic surgery with standardized anaesthesia technique and fluid administration. Arterial oxygen tension was maintained near 150 mmHg. PsqO(2) was measured from a surrogate wound on the upper arm. A mean FIO(2) of 51% (13%) was required in obese patients to reach an arterial oxygen tension of 150 mmHg; however, a mean FIO(2) of only 40% (7%) was required to reach the same oxygen tension in non-obese patients (P=0.007). PsqO(2) was significantly less in obese patients: 41 (10) vs 57 (15) mmHg (P<0.001). Obese patients having laparoscopic surgery require a significantly greater FIO(2) to reach an arterial oxygen tension of about 150 mmHg than non-obese patients; they also have significantly lower subcutaneous oxygen tensions. Both factors probably contribute to an increased infection risk in obese patients.

Real time dependency of subcutaneous tissue oxygenation on inspired oxygen concentrations

Real time dependency of subcutaneous tissue oxygenation on inspired oxygen concentrations

Supplemental oxygen and carbon dioxide each increase subcutaneous and intestinal intramural oxygenation.

Oxidative killing by neutrophils, a primary defense against surgical pathogens, is directly related to tissue oxygenation. We tested the hypothesis that supplemental inspired oxygen or mild hypercapnia (end-tidal PCO2 of 50 mm Hg) improves intestinal oxygenation. Pigs (25 +/- 2.5 kg) were used in 2 studies in random order: 1) Oxygen Study: 30% versus 100% inspired oxygen concentration at an end-tidal PCO2 of 40 mm Hg, and 2) Carbon Dioxide Study: end-tidal PCO2 of 30 mm Hg versus 50 mm Hg with 30% oxygen. Within each study, treatment order was randomized. Treatments were maintained for 1.5 h; measurements were averaged over the final hour. A tonometer inserted in the subcutaneous tissue of the left upper foreleg measured subcutaneous oxygen tension. Tonometers inserted into the intestinal wall measured intestinal intramural oxygen tension from the small and large intestines. Oxygen 100% administration doubled subcutaneous oxygen partial pressure (PO2) (57 +/- 10 to 107 +/- 48 mm Hg, P = 0.006) and large intestine intramural PO2 (53 +/- 14 to 118 +/- 72 mm Hg, P = 0.014); intramural PO2 increased 40% in the small intestine (37 +/- 10 to 52 +/- 25 mm Hg, P = 0.004). An end-tidal PCO2 of 50 mm Hg increased large intestinal PO2 approximately 16% (49 +/- 10 to 57 +/- 12 mm Hg, P = 0.039), whereas intramural PO2 increased by 45% in the small intestine (31 +/- 12 to 44 +/- 16 mm Hg, P = 0.002). Supplemental oxygen and mild hypercapnia each increased subcutaneous and intramural tissue PO2, with supplemental oxygen being most effective.

Subcutaneous tissue oxygen tension after coronary revascularisation with and without cardiopulmonary bypass.

Directly measured subcutaneous tissue oxygen tension reflects the adequacy of regional tissue oxygenation and influences wound infection and healing. We tested the hypothesis that off-pump coronary artery bypass would increase subcutaneous tissue oxygen tension by minimizing cardiopulmonary bypass-induced systemic inflammation. Ten consecutive patients scheduled for off-pump coronary artery bypass were compared with 10 undergoing conventional cardiopulmonary bypass. All patients had a tissue oxygen sensor implanted longitudinally into the subcutaneous tissue of the leg in the saphenous vein harvest wound. Data were collected from closure of the saphenous vein wound for 20 h postoperatively. Although more off-pump patients had only one coronary artery grafted, postoperative subcutaneous tissue oxygen tension was significantly higher in off-pump patients throughout the 20-h study. Absolute mean (SD) differences ranged from 2.3 kPa in the first 2 h [14.4 (2.3) vs. 12.1 (2.4) kPa in off-pump and cardiopulmonary bypass, respectively, p = 0.04] to 4.6 kPa at 8-10 h [14.0 (3.5) vs. 9.3 (2.7) kPa, p = 0.007]. In contrast, there were no significant differences in arterial oxygen tension values over this period. Mean arterial pressure and haemoglobin were transiently higher in off-pump patients at 8 h only. We conclude that postoperative subcutaneous tissue oxygen tension was higher for 20 h after off-pump compared with conventional cardiopulmonary bypass.

Development of subcutaneous wound oxygen measurement in humans: contributions of Thomas K Hunt, MD.

When, in the early 1960s, Thomas K. Hunt, MD began investigating the role of oxygen in wound healing, he recognized that translation to humans would require the ability to measure oxygen tension in human wounds. This article will review his contributions to the development of subcutaneous tissue oxygen measurement and to the understanding of wound physiology and oxygen delivery, particularly through use of oxygen measurement. Hunt's major contributions to the field include the observations that all wounds show some degree of hypoxia, while many are severely hypoxic; the degree of hypoxia in wounds is sufficient to impair wound healing, and particularly bacterial killing by neutrophils, collagen deposition, angiogenesis, and epithelization; the sympathetic nervous system plays a central role in decreasing wound oxygen supply; and wound oxygen delivery and wound healing capacity can be increased by controlling the sympathetic nervous system. All these observations required tissue oxygen measurement, and, in particular, translation of basic scientific observations to clinical research required a method of measuring wound oxygen tension in humans.

Effects of an Augmented Postoperative Fluid Protocol on Wound Healing in Cardiac Surgery Patients

Cardiac surgery patients are vulnerable to hypoperfusion postoperatively and often have subcutaneous tissue oxygen tension less than 50 mm Hg. Hypovolemia most likely contributes to this hypoperfusion and may lead to impaired wound healing. To determine if a modified postoperative fluid replacement protocol would result in improved tissue oxygen tension, blood flow, and healing in cardiothoracic surgery patients. A total of 166 cardiac surgery patients, 18 to 90 years old, participated in a randomized, 2-group, repeated-measures study. The experimental group received fluid augmentation during the first 36 hours after surgery; the control group received standard postoperative replacement fluids. Subcutaneous tissue oxygen tension and temperature were measured 8, 18, and 36 hours after surgery. Tissue cellularity and accumulation of hydroxyproline were evaluated in tissue obtained from subcutaneous expanded polytetrafluoroethylene tubes. Wound complications were evaluated by using the ASEPSIS Wound Scoring System. Tissue oxygen levels, tissue cellularity, and accumulation of hydroxyproline were similar in the 2 groups. A negative correlation (P = .01) existed between higher tissue oxygen values and lower (better) ASEPSIS leg wound scores. More than 80% of the patients had tissue oxygen levels of 50 mm Hg or less at each time of measure. Many values were 30 to 40 mm Hg less than the ideal for control of bacteria and healing. The frequency of low oxygen levels is consistent with data from earlier studies. Determination of other interventions to improve subcutaneous tissue perfusion in cardiac surgery patients is needed.

Comparison between Tissue Oxygen Saturation as Determined by Near-Infrared Spectroscopy and Direct Measurements of Subcutaneous Tissue Oxygen

Comparison between Tissue Oxygen Saturation as Determined by Near-Infrared Spectroscopy and Direct Measurements of Subcutaneous Tissue Oxygen

Tissue oxygenation and perfusion in patients with systemic sepsis.

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. Prospective, observational study. Adult intensive care unit, tertiary referral center. Volunteers (group C, n = 7), patients undergoing cardiopulmonary bypass (group B, n = 6), and patients with severe sepsis (group S, n = 6). Limb ischemia and reperfusion. 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). 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.