Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2005
Randomized Controlled Trial Clinical TrialA rapid increase in the inspired concentration of desflurane is not associated with epileptiform encephalogram.
The large inspired concentration of sevoflurane (S) during mask induction of anesthesia can induce epileptiform electroencephalogram (EEG) associated with tachycardia. Tachycardia is also seen when the concentration of desflurane (D) is abruptly increased. It is not known whether this is associated with epileptiform EEG similar to S. We studied EEG and heart rate (HR) during rapidly increased concentrations of S or D in 31 females during the postintubation period of anesthesia. Anesthesia was induced with propofol and remifentanil, and the tracheas were intubated. Patients were randomized to receive either S or D in nitrous oxide-oxygen mixture after intubation, at a small dose first. After 10 min, S or D vaporizer was advanced to the highest reading of the vaporizer (7% for S, 18% for D) for 5 min. HR and EEG were recorded. Epileptiform EEG activity was recorded in eight of 15 patients in group S and in none in group D (P < 0.05). HR increased in both groups. In group S, HR increased gradually and the highest HR value was 84 bpm at 5 min after the increase in sevoflurane concentration. In group D, HR increased to 93 bpm 2 min after the increase in desflurane concentration (no significant difference, S versus D). A rapid increase in the concentration of S frequently induces epileptiform EEG during normoventilation. Tachycardia during increasing concentrations of D is not associated with epileptiform EEG. ⋯ A rapid increase in the concentration of sevoflurane induces epileptiform encephalogram (EEG) with tachycardia. A rapid increase in the concentration of desflurane also induces tachycardia but is not associated with epileptiform EEG.
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Anesthesia and analgesia · Aug 2005
Randomized Controlled Trial Clinical TrialThe effect of different isoflurane-fentanyl dose combinations on early recovery from anesthesia and postoperative adverse effects.
We evaluated the effect of different combinations of fentanyl-isoflurane on early recovery from anesthesia in 80 adult patients undergoing laparoscopic cholecystectomy. Anesthesia was induced with fentanyl 2 microg/kg and thiopental 5 mg/kg. Nitrous oxide was not used and patients were randomly assigned to one of four groups: Group 1 (n = 20) received 0.6% end-tidal isoflurane plus fentanyl, Group 2 (n = 20) received 1.2% end-tidal isoflurane plus fentanyl, Group 3 (n = 20) received 1.8% end-tidal isoflurane plus fentanyl, and Group 4 (n = 20) received only isoflurane. In Groups 1, 2 and 3 isoflurane concentration was kept constant and fentanyl was given as necessary to maintain the mean arterial blood pressure within +/- 10% of the minimum mean arterial blood pressure measured in the ward. In Group 4, isoflurane concentration was adjusted to maintain mean arterial blood pressure as above. At the end of skin closure isoflurane was discontinued and the time to spontaneous breathing (TSB), time to extubation (TE) and time to eye opening (TEO) were recorded. In the postanesthesia care unit, the degree of sedation, respiratory rate, Spo(2), emesis, pain, and morphine consumption were evaluated every 15 min for 1 h, and thereafter every 30 min until discharge. Fentanyl requirements were 8.3 +/- 4.5 microg/kg (mean +/- sd) in Group 1, 3.8 +/- 1.3 microg/kg in Group 2, and 3.0 +/- 0.7 microg/kg in Group 3 (P < 0.001), whereas in Group 4 the mean end-tidal concentration of isoflurane was 2.0% +/- 0.4%. Although the mean TSB was <5.5 min in all groups, TE increased from 7.3 +/- 5.1 min in Group 1 to 20.6 +/- 10.7 min in Group 4 (P < 0.001), and TEO increased from 7.4 +/- 5.1 min in Group 1 to 25.8 +/- 9.4 min in Group 4 (P < 0.001). There were no differences among the groups in any of the variables measured in the postanesthesia care unit. This study shows that the combination of a small concentration of isoflurane and a relatively larger dose of fentanyl results in a faster recovery from anesthesia than the inverse combination of doses. ⋯ A fast recovery from anesthesia increases patient safety. This study shows that the combination of a small concentration of isoflurane and a relatively larger dose of fentanyl results in a faster recovery from anesthesia than the inverse combination of doses.
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Anesthesia and analgesia · Aug 2005
ReviewNitric oxide synthase inhibition in sepsis? Lessons learned from large-animal studies.
Nitric Oxide (NO) plays a controversial role in the pathophysiology of sepsis and septic shock. Its vasodilatory effects are well known, but it also has pro- and antiinflammatory properties, assumes crucial importance in antimicrobial host defense, may act as an oxidant as well as an antioxidant, and is said to be a "vital poison" for the immune and inflammatory network. Large amounts of NO and peroxynitrite are responsible for hypotension, vasoplegia, cellular suffocation, apoptosis, lactic acidosis, and ultimately multiorgan failure. ⋯ Thus, the issue of NOS inhibition in sepsis remains a matter of debate. Several publications have emphasized the differences concerning clinical applicability of data obtained from unresuscitated, hypodynamic rodent models using a pretreatment approach versus resuscitated, hyperdynamic models in high-order species using posttreatment approaches. Therefore, the present review focuses on clinically relevant large-animal studies of endotoxin or living bacteria-induced, hyperdynamic models of sepsis that integrate standard day-to-day care resuscitative measures.
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Anesthesia and analgesia · Aug 2005
ReviewIntraoperative fluid restriction improves outcome after major elective gastrointestinal surgery.
Fluid therapy is one of the most controversial topics in perioperative management. There is continuing debate with regard to the quantity and the type of fluid resuscitation during elective major surgery. However, there are increasing reports of perioperative excessive intravascular volume leading to increased postoperative morbidity and mortality. ⋯ Furthermore, predetermined algorithms that suggest replacement of third space losses and losses through diuresis are unnecessary. Significant reduction in crystalloid volume can be achieved without encountering intraoperative hemodynamic instability or reduced (i.e., < 0.5 mL x kg(-1) x h(-1)) urinary output just by avoiding replacement of third space losses and preloading. Finally, there is a need for well-controlled studies in a well-defined patient population using clear criteria or end-points for perioperative fluid therapy.
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Anesthesia and analgesia · Aug 2005
Comparative StudyUltrasound guidance for facet joint injections in the lumbar spine: a computed tomography-controlled feasibility study.
We conducted this study to develop an ultrasound-guided approach for facet joint injections of the lumbar spine. Five zygapophyseal joints (L1-S1) on each side of 5 embalmed cadavers were examined by ultrasound for a total of 50 examinations. The joint space was demonstrated under ultrasound guidance. The midpoint of the joint space, defined as the middle of its cranio-caudal extension on its dorsal surface, was taken as a reference point, and its position was computed from its depth and lateral distance from the spinous process. Forty-two of 50 approaches could be clearly visualized. Subsequently, these distances were compared to those obtained by computed tomography (CT). To assess the efficacy of ultrasound in the needle placement, all lumbar facet joints were approached in one embalmed cadaver. The exact placement of the needle tips was again evaluated by CT. Ultrasound and CT measurements showed the same mean depth and lateral distance to the reference point, 3.15 +/- 0.5 cm and 1.9 +/- 0.6 cm, respectively. Pearson's coefficient of correlation was 0.86 (P < 0.0001) between ultrasound and CT. All 10 needle tips were within the joint space during simulated facet joint injections. We conclude that ultrasound guidance might be a useful adjunct for facet joint injections in the lumbar spine. ⋯ This study was designed to develop an ultrasound-guided approach to the facet joints of the lumbar spine and to assess its feasibility and accuracy by means of a comparison to computed tomography images. The imaging study demonstrated a significant correlation between ultrasound and computed tomography measurements. During simulated facet injection, ultrasound guidance consistently resulted in accurate needle placement.