Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1999
Which clinical anesthesia outcomes are important to avoid? The perspective of patients.
Healthcare quality can be improved by eliciting patient preferences and customizing care to meet the needs of the patient. The goal of this study was to quantify patients' preferences for postoperative anesthesia outcomes. One hundred one patients in the preoperative clinic completed a written survey. Patients were asked to rank (order) 10 possible postoperative outcomes from their most undesirable to their least undesirable outcome. Each outcome was described in simple language. Patients were also asked to distribute $100 among the 10 outcomes, proportionally more money being allocated to the more undesirable outcomes. The dollar allocations were used to determine the relative value of each outcome. Rankings and relative value scores correlated closely (r2 = 0.69). Patients rated from most undesirable to least undesirable (in order): vomiting, gagging on the tracheal tube, incisional pain, nausea, recall without pain, residual weakness, shivering, sore throat, and somnolence (F-test < 0.01). ⋯ Although there is variability in how patients rated postoperative outcomes, avoiding nausea/vomiting, incisional pain, and gagging on the endotracheal tube was a high priority for most patients. Whether clinicians can improve the quality of anesthesia by designing anesthesia regimens that most closely meet each individual patient's preferences for clinical outcomes deserves further study.
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Anesthesia and analgesia · Sep 1999
Cerebral venous and tissue gases and arteriovenous shunting in the dog.
Cerebral venous blood gas values have been used to indicate brain tissue oxygenation. However, it is not clear how cerebral tissue and venous measures may vary under physiologic conditions caused by arteriovenous shunt. The purpose of this study was to measure brain tissue and local cerebral venous oxygen (PO2) and carbon dioxide (P(CO2)) partial pressure during changes in ventilation and to calculate shunt fraction. Eight dogs were anesthetized with isoflurane. After a craniotomy, a Neurotrend probe (Diametrics Inc., St. Paul, MN) that measures P(O2), P(CO2), pH, and temperature was inserted into brain tissue, and a small vein that drained the same tissue was catheterized. Arterial, cerebral venous, and brain tissue P(O2) and Pco2 were measured during random changes in ventilation to produce five different levels of inspired oxygen (room air, 40%, 60%, 80%, 95%) at each of three different end-tidal Pco2 (20 mm Hg, 40 mm Hg, 60 mm Hg). Arteriovenous shunt was calculated from oxygen and C(O2) content in artery, vein, and tissue, representing capillary. Tissue P(CO2) was 8 mm Hg greater than vein Pco2 during hypocapnia and this difference increased to 20 mm Hg during hypercapnia. Vein P(O2) was 8 mm Hg higher than tissue P(O2) during hypocapnia, and this difference increased to 40 mm Hg during hypercapnia. Shunt fraction increased from 10%-20% during hypocapnia to 50%-60% during hypercapnia. These results show that brain vein and tissue P(O2) and P(CO2) differ because of arteriovenous shunting and this difference is increased as end-tidal P(CO2) increases. ⋯ We found, in dogs, that the gradient between brain venous and tissue P(O2) and PCO2 is increased with increased arterial P(CO2). The divergence between tissue and venous gases can be described by arterial to venous shunting.
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Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Comparative Study Clinical TrialMetabolic and hemodynamic changes during recovery and tracheal extubation in neurosurgical patients: immediate versus delayed recovery.
Delayed recovery has been advocated to limit the postoperative stress linked to awakening from anesthesia, but data on this subject are lacking. In this study, we measured oxygen consumption (V(O2)) and plasma catecholamine concentrations as markers of postoperative stress. We tested the hypothesis that delayed recovery and extubation would attenuate metabolic changes after intracranial surgery. Thirty patients were included in a prospective, open study and were randomized into two groups. In Group I, the patients were tracheally extubated as soon as possible after surgery. In Group II, the patients were sedated with propofol for 2 h after surgery. V(O2), catecholamine concentration, mean arterial pressure (MAP), and heart rate (HR) were measured during anesthesia, at extubation, and 30 min after extubation. V(O2) and noradrenaline on extubation and mean V(O2) during recovery were significantly higher in Group II than in Group I (V(O2) for Group I: preextubation 215 +/- 46 mL/min, recovery 198 +/- 38 mL/min; for Group II: preextubation 320 +/- 75 mL/min, recovery 268 +/- 49 mL/min; noradrenaline on extubation for Group I: 207 +/- 76 pg/mL, for Group II: 374 +/- 236 pg/ mL). Extubation induced a significant increase in MAP. MAP, HR, and adrenaline values were not statistically different between groups. In conclusion, delayed recovery after neurosurgery cannot be recommended as a mechanism of limiting the metabolic and hemodynamic consequences from emergence from general anesthesia. ⋯ In this study, we tested the hypothesis that delayed recovery after neurosurgery would attenuate the consequences of recovery from general anesthesia. As markers of stress, oxygen consumption and noradrenaline blood levels were higher after delayed versus early recovery. Thus, delayed recovery cannot be recommended as a mechanism of limiting the metabolic and hemodynamic consequences from emergence after neurosurgery.