Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2000
Randomized Controlled Trial Clinical TrialLow-flow desflurane and sevoflurane anesthesia minimally affect hepatic integrity and function in elderly patients.
Hepatic blood flow is reduced in a dose-related manner by all inhaled anesthetics now in use. We assessed hepatic function in elderly patients anesthetized with desflurane or sevoflurane. We measured the cytosolic liver enzyme alpha glutathione S-transferase (alpha GST), the formation of the lidocaine metabolite monoethylglycinexylidide (MEGX), and gastric mucosal tonometry-derived variables as sensitive markers of hepatic function and splanchnic perfusion. Thirty patients, 70 to 90 yr old, were allocated randomly to receive desflurane or sevoflurane anesthesia. Anesthetic exposure ranged from 2.1-4.5 minimum alveolar concentration hours. No significant changes in standard liver enzyme markers were seen throughout the study. In both anesthetic groups, tonometric measurements showed a significant decrease from baseline in regional PCO(2), regional to arterial difference in PCO(2), and intramucosal pH at 90 min after skin incision. alpha GST concentrations increased significantly in both groups (desflurane: median peak concentrations 5.8 microg/L [25th, 75th percentile 5.3 microg/L, 7.2 microg/L]; sevoflurane: 7.0 microg/L [5.8 microg/L, 7.3 microg/L]) without showing differences between both anesthetic groups. A return to baseline values in tonometric values and alpha GST levels was seen 24 h postoperatively. MEGX formation did not change significantly after surgery. Median MEGX concentrations postoperatively were 70.0 ng/mL (56.2 ng/mL, 102.0 ng/mL) and 70.0 ng/mL (60.0 ng/mL, 94.2 ng/mL) in the desflurane and sevoflurane groups, respectively. We conclude that, overall, liver function in elderly patients is well preserved during desflurane and sevoflurane anesthesia. Increased serum levels of alpha GST and changes of gastric tonometry-derived variables imply a reduction in splanchnic perfusion, leading to a temporary impairment of hepatocyte oxygenation. ⋯ We measured the lidocaine metabolite monoethylglycinexylidide, the cytosolic liver enzyme, alpha glutathione S-transferase, and gastric mucosal tonometry-derived variables to evaluate the effects of desflurane and sevoflurane on hepatic function in elderly patients. Liver function was well preserved, whereas increased alpha glutathione S-transferase levels and changes in tonometry-derived variables indicated a reduction in splanchnic blood flow and a temporary impairment of hepatocyte oxygenation for both anesthetics.
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Anesthesia and analgesia · Jul 2000
Assessing a tool to measure patient functional ability after outpatient surgery.
The "24-Hour Functional Ability Questionnaire" (24hFAQ) was developed to measure final recovery and satisfaction 24 h after surgery. We used structured interviews preoperatively to measure baseline patient concerns, and up to 24 h after discharge, to assess patient function and satisfaction. The primary objective was to assess the validity of the newly developed 24hFAQ in the postoperative outpatient setting. The criteria assessed were 1) CONTENT: comparison with expert opinion and patients' views and response frequency distributions for asymptotes and irrelevance, 2) Construct: contribution of cognitive, physical, and satisfaction domains to postoperative functional ability, 3) Discrimination: comparing mean clinical end points with patient satisfaction, and 4) Criterion (predictive) validity: testing that related constructs are best correlated. CONTENT validity was supported by the appropriate frequency distribution of subject responses, by the lack of floor or ceiling effects, and by <2% of responses indicating irrelevance. Construct validity was supported by moderate-to-strong positive interitem correlations within the cognitive and physical domains as predicted a priori. Discriminant validity support was mixed: key symptoms were associated with adverse patient satisfaction, but operating room and postanesthesia care unit residence times were unrelated. Criterion validity was supported by the finding that preoperative concern with key symptoms was independent of postoperative outcomes. The validity assessment presented was the first assessment of the measurement capability of the 24hFAQ in an outpatient postoperative population. These results provide overall support for the validity of the 24hFAQ for use in outpatient populations. ⋯ This study assessed the validity of a novel functional ability questionnaire that measured functional status after recovery from anesthesia and satisfaction 24 h after outpatient surgery. The content, construct, discriminant, and criterion (predictive) validities demonstrated the utility of this assessment instrument in the outpatient setting.
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Anesthesia and analgesia · Jul 2000
Potassium as a surrogate marker of debris in cell-salvaged blood.
Centrifuge-based cell salvage systems have decreased the use of homologous blood transfusions. Although the evidence is anecdotal, the risk associated with the use of salvaged erythrocytes seems related to cellular and chemical contaminants. We sought to determine if potassium can be a surrogate marker for cellular debris and to measure the residual heparin level. Four units of expired whole blood were heparinized and concentrated with a Sequestra 1000 (Medtronics), Parker, CO) cell salvage device. The potassium, free hemoglobin, leukocyte, and platelet counts were sampled after each 250-mL normal saline wash aliquot, to a total wash volume of 1500 mL, whereas the heparin samples were obtained at wash volumes 0 and 1000 mL. Potassium, leukocyte, and platelet concentrations at wash volumes 0 and 250 mL were significantly greater than at all other volumes (P < 0.001). After 500 mL of saline wash, the change in these values was not significant. The mean (+/- SD) heparin levels (units/mL) at wash volumes 0 and 1000 mL were 10.2 (+/-3.1) and 0.11 (+/-0.02), respectively (P < 0.007). The r(2) values for free hemoglobin, leukocytes, and platelets versus potassium were 0.006, 0.992, and 0.995, respectively. No convenient test has been validated as an indicator of salvaged erythrocyte cleanliness. This in vitro study suggests that residual potassium concentration seems to be a good indicator of quality after washing with a contemporary intraoperative salvage system. ⋯ No convenient test has been validated as an indicator of salvaged erythrocyte cleanliness. This in vitro study suggests that residual potassium concentration seems to be a good indicator of quality after washing with a contemporary intraoperative salvage system.