Noninvasive, near infrared spectroscopic-measured muscle pH and Po2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass*
Autor: | Thomas J. Vander Salm, Sinan A. Simsir, Helen Collette, Steven D. Levin, Babs R. Soller, Patrick O. Idwasi, Jorge Balaguer, Stephen O. Heard |
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Rok vydání: | 2003 |
Předmět: |
Male
medicine.medical_specialty Coronary Disease Critical Care and Intensive Care Medicine Sensitivity and Specificity law.invention Coronary artery disease Oxygen Consumption Predictive Value of Tests law Monitoring Intraoperative Intensive care medicine Cardiopulmonary bypass Humans Postoperative Period Prospective Studies Coronary Artery Bypass Muscle Skeletal Aged Cardiopulmonary Bypass Spectroscopy Near-Infrared business.industry Near-infrared spectroscopy Carbon Dioxide Hydrogen-Ion Concentration Middle Aged medicine.disease Cardiac surgery Blood pressure Anesthesia Breathing Female business Perfusion |
Zdroj: | Critical Care Medicine. 31:2324-2331 |
ISSN: | 0090-3493 |
Popis: | OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and monitored intensive care period. Near infrared spectroscopic pH decreased significantly during cardiopulmonary bypass, decreased significantly during rewarming, and remained depressed 6 hrs after cardiopulmonary bypass. Diabetic patients responded differently than nondiabetic subjects to cardiopulmonary bypass, with lower muscle pH values (p =.02). CONCLUSIONS: Near infrared spectroscopic-measured muscle pH and Po2 are sensitive to changes in tissue perfusion during cardiopulmonary bypass. |
Databáze: | OpenAIRE |
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