Transcutaneous Oxygen Tension Monitoring Research Articles

Transcutaneous oxygen tension monitoring in critically ill patients receiving packed red blood cells

PurposeWhether transfusions of packed red blood cells (PRBCs) affect tissue oxygenation in stable critically ill patients is still matter of discussion. The microvascular capacity for tissue oxygenation can be determined noninvasively by measuring transcutaneous oxygen tension (tcpO2). The aim of this study was to assess tissue oxygenation by measuring tcpO2 in stable critically ill patients receiving PRBC transfusions. MethodsNineteen stable critically ill patients, who received 2 units of PRBC, were prospectively included into this pilot study. Transcutaneous oxygen tension was measured continuously during PRBC transfusions using Clark's electrodes. In addition, whole blood viscosity and global hemodynamics were determined. ResultsReliable measurement signals during continuous tcpO2 monitoring were observed in 17 of 19 included patients. Transcutaneous oxygen tension was related to the global oxygen consumption (r = −0.78; P = .003), the arterio-venous oxygen content difference (r = −0.65; P = .005), and the extraction rate (r = −0.71; P = .02). The transfusion-induced increase of the hemoglobin concentration was paralleled by an increase of the whole blood viscosity (P < .001). Microvascular tissue oxygenation by means of tcpO2 was not affected by PRBC transfusions (P = .46). Packed red blood cell transfusions resulted in an increase of global oxygen delivery (P = .02) and central venous oxygen saturation (P = .01), whereas oxygen consumption remained unchanged (P = .72). ConclusionsIn stable critically ill patients, microvascular tissue oxygenation can be continuously monitored by Clark's tcpO2 electrodes. According to continuous tcpO2 measurements, the microvascular tissue oxygenation is not affected by PRBC transfusions.

Guidelines for the treatment of arterial insufficiency ulcers

1. Co-chaired panel 2. University of Utah, Salt Lake City, UT 3. University of Texas, San Antonio, TX 4. Sinai Hospital/Johns Hopkins Medical Institutions, Baltimore, MD 5. GKT School of Medicine, King’s College, London, UK 6. University of Texas Health Science Center at Houston, TX 7. Sequoia Hospital, Redwood City, CA 8. Maricopa Medical Center, Phoenix, AZ 9. Tufts-New England Medical Center, Boston, MA 10. Southampton University Hospitals Trust NHS, Southampton, UK 11. Penrose–St. Francis Health Services, Colorado Springs, CO 12. Beverly Surgical Associates, Beverly, MA 13. Saint Francis Memorial Hospital, San Francisco, CA 14. Northbay Center for Wound Care, Vacaville, CA, and 15. University of California, San Francisco, CA

Microdialyse et monitorage des lambeaux libres à palette cutanée en chirurgie maxillo-faciale

The development of in vivo microdialysis has made it possible to monitor cutaneous free flaps in maxillo-facial surgery. A microprobe inserted in the free flap dermis collects a microdialysate enabling measurement of dermal metabolites such as glucose, lactate, pyruvate, or glycerol. The monitoring curves are predictive of ischemia-related tissue injury. Hourly measurements provide a reliable method for early diagnosis of venous or arterial thrombosis. Revision surgery can then be undertaken if needed to repair microanastomoses before clinical alteration. This technique has been compared with validated flaps monitoring systems such as temperature probe, transcutaneous oxygen tension monitoring, and laser Doppler flowmetry. Microdialysis has several advantages: objective measurements, different curves for venous and arterial thrombosis, early diagnosis. Accessibility to oral cavity or pharyngeal flaps requires careful clinical analysis (microprobe fixation, anatomy and choice of flap).

The differential effect of the level of spinal cord stimulation on patients with advanced peripheral vascular disease in the lower limbs

Percutaneous spinal cord stimulation (SCS) (Medtronic model 3487A PISCES-Quad lead) was carried out in 10 patients with rest pain from advanced peripheral vascular disease of the lower limb, who were unsuitable for conventional treatment. Trial stimulation ranged from 1-20 weeks and was associated with pain relief in nine of the patients. Claudication distance was improved in six patients. Trophic lesions improved in one patient with small artery disease. Spinal cord stimulation did not reverse the course of acute gangrenous lesions. The distal arterial pressure measured by Doppler Ankle/Brachial Pressure Index, (ABPI), showed no change. The capillary blood flow and skin temperature of both feet, measured, respectively, by Laser Doppler flowmetry and skin thermistor, showed a tendency to decrease when the stimulation was at the higher level, above T10, compared with an increase when the stimulation was at the lower level T12. Transcutaneous oxygen tension monitoring of the symptomatic foot showed an increase in four out of five patients. Pain relief was not dependent on circulatory changes, but it was more significant when the circulatory changes showed an impressive increase in the blood flow. The mechanism of these circulatory changes is probably by modulation of the sympathetic nervous system. Recognition of the optimal siting of SCS may be critical in the clinical use of this technique, which seems to be a valuable option in the treatment of patients with advanced peripheral vascular disease (PVD).

Intraoperative Transcutaneous Oxygen Tension Criteria for Completion Arteriography

During the past three years, we studied the value of transcutaneous oxygen monitoring in 28 lower extremity vascular bypass procedures. In 21 reconstructions, a rapid rise in the transcutaneous oxygen tension following reperfusion was indicative of a patent graft and patent runoff vessels. Inadequate revascularization was identified in three of four patients in whom transcutaneous oxygen tension failed to rise following femorodistal arterial bypass (positive predictive value 75%). A normal intraoperative transcutaneous oxygen tension study following femorodistal bypass had a negative predictive value of 95%. The overall accuracy was 91%. Transcutaneous oxygen tension monitoring during lower extremity vascular bypass procedures is useful in assessing the success of revascularization and may be used to select which patients should undergo completion arteriography as opposed to those in whom an arteriogram is not essential.

Evaluation of transcutaneous oxygen tension monitoring during cosmetic surgery

Evaluation of transcutaneous oxygen tension monitoring during cosmetic surgery

Sleep Apnea in Severely Handicapped Patients: Blood Gas Analysis and Transcutaneous Oxygen Tension Monitoring

Sleep Apnea in Severely Handicapped Patients: Blood Gas Analysis and Transcutaneous Oxygen Tension Monitoring

Evaluation of transcutaneous oxygen tension monitoring during cosmetic surgery.

Transcutaneous oxygen monitoring during rhytidectomy surgery under local anesthesia was evaluated in 18 patients. Blood gas analysis of samples of arterial blood obtained from the superficial temporal arteries during rhytidectomy was compared with transcutaneous PO2 values. Simple linear regression analysis indicated that the transcutaneous PO2 correlates strongly with arterial PO2. Transcutaneous PO2 monitoring could be a reliable, inexpensive, and continuous method of assessing gradual or sudden changes in arterial PO2, provided the sensor is fastidiously maintained and properly applied, elements which are critical to relying on this particular device. However, this instrument has no advantages over the digital pulse oximeter.

The value of laser Doppler velocimetry and transcutaneous oxygen tension determination in predicting healing of ischemic forefoot ulcerations and amputations in diabetic and nondiabetic patients

The ability to predict successful healing of ulcerations and amputations of the ischemic forefoot continues to be a major clinical challenge, particularly in diabetic patients whose systolic Doppler ankle pressures are often artifactually elevated. We have used the techniques of laser Doppler velocimetry (LD) and transcutaneous oxygen tension monitoring (tcPo2) to quantitatively measure skin blood flow in the distal foot. Fifty-nine limbs were studied (48 patients), of which 37 (63%) were in diabetic and 22 (37%) in nondiabetic patients. All patients were admitted with ischemic ulcerations or gangrenous changes of the forefoot or digit. Twenty transmetatarsal or digital amputations were performed; the remainder of the lesions were débrided and allowed to heal by secondary intention or were covered by a skin graft. Before operation, the systolic pressure (expressed in millimeters of mercury, mean ± SEM) was measured by Doppler technique at the ankle, and the ankle/arm index calculated (n = 59 limbs). The tcPO1 (also expressed in millimeters of mercury, mean ± SEM) was measured from the dorsal foot (n = 56). The baseline skin blood flow velocity (SBFV) and pulse wave amplitude (PWA) were measured with the LD (expressed in millivolts, mean ± SEM) on the plantar aspect of the foot (n = 53 limbs). Criteria for successful healing included a tcPO2 of more than 10 mm Hg, the combination of an LD-SBFV of more than 40 mV and an LD-PWA of more than 4 mV, and an ankle systolic pressure of more than 30 mm Hg. With these criteria, the outcome was predicted correctly in 53 of 56 limbs (95%) by tcPO2, in 46 of 53 limbs (87%) with LD, and in 31 of 59 limbs (52%) with Doppler ankle systolic pressures. We conclude that the estimation of skin blood flow by tcPO2 and LD is significantly (p < 0.05) better than Doppler ankle pressure measurements in predicting the healing of forefoot ulcerations and amputations in diabetic and nondiabetic patients.

Continuous conjunctival and transcutaneous oxygen tension monitoring during resuscitation in a patient

Conjunctival ( PcjO 2) and transcutaneous ( PtcO 2) oxygen tensions were serially measured in a patient with multiple stab wounds. Even though blood pressure was normal, severe hypovolemia due to hemorrhage was detected in the emergency department by abnormally low P cjO 2 P aO 2 and P tcO 2 P aO 2 ratios. The adequacy of resuscitation was established by return of these ratios to normal values. The conjunctival sensor stabilized more rapidly than the transcutaneous sensor and is of greater utility in the emergency setting. It was found that conjunctival and transcutaneous oxygen sensors can play an important role in monitoring clinical state and resuscitation of trauma patients.

Continuous transcutaneous oxygen tension monitoring during ultralight general anesthesia for oral surgery

The application of continuous, noninvasive, transcutaneous oxygen tension monitoring during ultralight general anesthesia is investigated. Transcutaneous PO 2 measurements showed a high correlation to simultaneously measured arterial PO 2. Significant hypoxia was observed in patients maintained on only room air during ultralight general anesthesia. In patients receiving supplemental oxygen by nasal mask, hyperoxic levels were noted throughout anesthesia, providing a significant margin of safety from hypoxia during periods of apnea or respiratory impairment.