Inhalational techniques in ambulatory anesthesia

In the current health care environment, anesthesia practitioners are frequently required to reevaluate their practice to be more efficient and cost-effective. Although IV induction with propofol and inhalational induction with sevoflurane are both suitable techniques for outpatients, patients prefer IV induction. Maintenance of anesthesia with the newer inhaled anesthetics (ie, desflurane and sevoflurane) provide for a rapid early recovery as compared with infusion of propofol (ie, TIVA), while allowing easy titratability of anesthetic depth. Titration of hypnotic sedatives using BIS monitoring may reduce the time to awakening and thereby may facilitate fast tracking (ie, bypassing the PACU) and reduce hospital stay. Inhalational anesthesia is associated with a higher incidence of PONV, but no differences have been demonstrated with respect to late recovery (eg, PACU stay and home readiness). Although clinical differences between desflurane and sevoflurane appear to be small, desflurane may be associated with faster emergence, particularly in elderly and morbidly obese patients. Balanced anesthesia with IV propofol induction and inhalation anesthesia with N2O for maintenance, and an LMA for airway management, may be an optimal technique for ambulatory surgery. Inhalational anesthesia may have an economic advantage over a TIVA technique.     

Comparison of the hemodynamic effects of sevoflurane anesthesia induction and maintenancevs TIVA in CABG surgery

PURPOSE: To compare the hemodynamic effects of sevoflurane when used for induction and maintenance of anesthesia with a total intravenous technique in patients with known coronary artery disease (CAD). METHODS: Thirty patients undergoing elective coronary artery bypass graft (CABG) were randomly allocated to receive either sevoflurane (S group, n = 15) at a minimal concentration of 4% in oxygen for induction and at 0.5-2 MAC end-tidal concentration for maintenance, or a total intravenous technique (T group, n = 15) consisting of midazolam for induction and propofol for maintenance. In both groups, anesthesia was supplemented with sufentanil and muscle relaxation with cis-atracurium. Hemodynamic measurements included systemic and pulmonary pressures, heart rate, mixed venous oxygen saturation and cardiac output at the following times: pre-induction, 7 and 25 min post-induction, chest closure, one hour after surgery and pre and post tracheal extubation. RESULTS: More patients in the S group (8/15) presented bradycardia in the induction period (T:2/15) (P = 0.05). During maintenance of anesthesia, treatment of hypertension was more frequent in the T group (12/15) than in the S group (6/15) (P = 0.025). All other parameters were comparable. CONCLUSION: Induction of anesthesia in patients with CAD, VCRII with sevoflurane supplemented by sufentanil provided hemodynamic responses comparable with those of TIVA although bradycardia was observed more often with sevoflurane. Intraoperative control of systemic blood pressure was achieved with fewer interventions with a sevoflurane/sufentanil maintenance than with a propofol/sufentanil technique in CABG surgery.     

Total Intravenous Anesthesia with Midazolam, Remifentanil, Propofol and Cisatracurium in Morbid Obesity

Background: According to physical impairments of massive obesity, cardiac, respiratory and gastrointestinal physiology must be considered as much as pharmacokinetic behavior. Anesthetic management of morbidly obese patients has to be carefully planned, in order to minimize the increased risks of aspirative pneumonitis, hemodynamic instability and delay in recovery.The ideal anesthesia should provide a smooth and quick induction, allowing rapid airway control, prominent hemodynamic stability, and rapid emergence from anesthesia.To approach these ideal conditions,aTotal Intravenous Anesthesia (TIVA) with midazolam, remifentanil, propofol and cisatracurium was designed and analyzed. Methods: 10 consenting morbidly obese patients scheduled for elective Laparoscopic Adjustable Gastric Banding participated in the study.TIVA with midazolam, remifentanil, propofol and cisatracurium was used in all cases.Time to loss of consciousness, tracheal intubation, perianesthetic physiological parameters and complications, incidence of awareness with recall, recovery times, postoperative analgesia and costs of drugs were evaluated. Results:The analyzed data showed adequate time and physiological conditions for induction and tracheal intubation, stable maintenance with easy handling of deepness, low incidence of perianesthetic complications, excellent recovery performance and institutional efficiency. Conclusions: TIVA with midazolam, remifentanil, propofol and cisatracurium was found to be effective, secure, predictable and economic for the anesthetic management of morbidly obese patients.     

Anesthetic management of morbidly obese patients using inhalation induction with high concentrations of sevoflurane

We describe successful anesthetic management of three morbidly obese patients, using inhalation induction with high concentrations of sevoflurane. In morbidly obese patients, reduced airway space of the pharynx can cause upper airway obstruction after the induction of general anesthesia and may explain difficult mask ventilation. For these patients, careful airway management is essential during the anesthetic induction. In inhalation induction with sevoflurane, the incidence of transient apnea is lower and the control over depth of anesthesia is easier as compared with intravenous induction. Therefore, sevoflurane may be an excellent induction agent in morbidly obese patients with a potentially difficult airway.     

Comparison of total intravenous anesthesia and sevoflurane-fentanyl anesthesia for outpatient otorhinolaryngeal surgery

STUDY OBJECTIVE: To compare the recovery characteristics of two widely used anesthetic techniques: remifentanyl-propofol and sevoflurane-fentanyl in a standardized ambulatory population.DESIGN: Randomized, single-blinded study. SETTING: University-affiliated medical center. PATIENTS: 50 ASA physical status I and II patients undergoing elective ambulatory otorhinolaryngeal surgery. INTERVENTIONS: Patients were randomized two groups to receive total intravenous anesthesia (TIVA group) with remifentanil and propofol or sevoflurane-fentanyl (SF group). TIVA patients received induction with propofol 1.5 mg/kg intravenously (IV) and remifentanil 0.5 microg/kg IV. The anesthesia was continued with a continuous infusion of propofol 100 microg/kg/min and remifentanil 0.0625-0.25 microg/kg/min. The SF group received, at induction, fentanyl 2 microg/kg followed by propofol 1.5 mg/kg IV. Maintenance was obtained with 1 to 1.5 minimum alveolar concentration of sevoflurane and bolus of fentanyl 1 microg/kg IV as needed. MEASUREMENTS AND MAIN RESULTS: Early recovery times (eye opening, response to commands, extubation, orientation, operating room stay after surgery, and Aldrete score > or =9) and patient satisfaction were similar between the two groups. Postanesthetic discharge scoring system (PADSS) > or = 9 was significantly shorter for the TIVA group (135.9 +/- 51 vs. 103 +/- 32 min) (p < 0.01) but this difference was not associated with a shorter postanesthesia care unit (PACU) length of stay. CONCLUSION: Early recovery times are comparable between total intravenous anesthesia and sevoflurane-based anesthesia. Even though patients in the TIVA group achieved home readiness criteria in a significantly shorter time, this technique does not shorten PACU length of stay, which depends instead on multiple nonmedical and administrative issues.     

Postoperative Results after Desflurane or Sevoflurane Combined with Remifentanil in Morbidly Obese Patients

Background: This randomized prospective study with blinded postanesthesia care unit (PACU) observers compared the recovery profiles in morbidly obese patients who received sevoflurane or desflurane for maintenance of anesthesia in combination with a remifentanil target controlled infusion (TCI). Methods: 50 morbidly obese patients scheduled for laparoscopic gastric banding were included to receive BIS-guided sevoflurane or desflurane anesthesia with BIS-triggered inhalation boli in combination with remifentanil TCI. In the PACU, the following recovery scores were investigated: Modified Aldrete score, a modified Observers' Assessment of Alertness/Sedation Scale (OAA/S), pain numerical rating scale (NRS), oxygen saturation (SpO₂) and postoperative nausea and vomiting (PONV). Results: OAA/S and NRS pain scores showed a similar evolution in both groups from the moment of PACU admission up to 120 minutes after admission. In both groups, patients showed no serious hypoxemia during PACU stay. Incidence of PONV was shorter lasting in the sevoflurane group compared to the desflurane group. Conclusions: No clinically relevant difference was found in recovery in the PACU between morbidly obese patients anesthetized with desflurane or sevoflurane. Both agents resulted in satisfactory recovery in morbidly obese patients.     

Efficacy and effect of TIVA with propofol or dexmedetomidine versus sevoflurane without muscle relaxant during repair of the brachial plexus

BackgroundTotal intravenous anesthesia (TIVA) versus inhalational anesthesia was selected as the anesthetic method, in order to avoid the use of muscle relaxants during repair of brachial plexus injury. We designed this study to determine effect and efficacy of TIVA versus sevoflurane during repair of brachial plexus injury.MethodsSixty patients scheduled for repair of injured brachial plexus from January 2009 till December 2011 were enrolled in this prospective, single-blind, randomized study. They received either inhalation induction with sevoflurane and maintenance with sevoflurane and fentanyl (Group 1) or TIVA with, propofol and fentanyl (Group 2) or TIVA with dexmedetomidine and fentanyl (Group 3). Hemodynamics, intubation conditions, sedation score were assessed. Postoperative pain using visual analogue scale (VAS) was assessed. Discharge time, postoperative respiratory condition, any postoperative complications were recorded.ResultsAll groups provided a similar significant reduction in hemodynamics compared with baseline values. Respiratory rate values of dexmedetomidine–fentanyl group were significantly higher than those in other groups. Oxygen saturation values of dexmedetomidine–fentanyl group were significantly higher than those of propofol–fentanyl group. Time to reach an Aldrete score of 10 was similar in all groups. Patients in sevoflurane–fentanyl group have significantly higher visual analogue score than other groups. Sedation score was higher in the dexmedetomidine–fentanyl group.ConclusionTIVA with propofol and with dexmedetomidine was more effective and favorable anesthesia than sevoflurane anesthesia during repair of brachial plexus injury.     

Dynamic cerebral blood flow autoregulation during sevoflurane anesthesia and TIVA

BACKGROUND: Dynamic cerebral blood flow autoregulation during sevoflurane anesthesia and total intravenous anesthesia (TIVA) is unclear. We examined the cerebral circulation autoregulation during anesthesia by sevoflurane or TIVA. METHODS: We measured mean blood pressure (MBP) and blood flow velocity of the middle cerebral artery by a transcranial Doppler ultrasonography before and during anesthesia using sevoflurane (volatile induction and maintenance of anesthesia (VIMA) group) and using propofol and fentanyl (TIVA group), and the relationship between changes in MBP and cerebral blood flow velocity was evaluated using the method of transfer function analysis. We calculated transfer gain and coherence by cross-spectrum from autospectra of MBP and cerebral blood flow velocity. RESULTS: Transfer gain during anesthesia by TIVA in the low frequency range and high frequency range was near 1 cm.sec-1.mmHg-1. It was about equal to the value of transfer gain before anesthesia. But transfer gain during anesthesia by VIMA was above 2 cm.sec-1.mmHg-1. CONCLUSION: These results suggest that TIVA by propofol and fentanyl maintains the dynamic autoregulation of cerebral blood flow, but sevoflurane impairs the autoregulation.     

Intraocular pressure more reduced during anesthesia with propofol than with sevoflurane: both combined with remifentanil

BACKGROUND: Short-acting anesthetic agents are suitable and commonly used in ocular surgery. Propofol and remifentanil are known to reduce intraocular pressure (IOP), but no information is available regarding the effects of sevoflurane combined with remifentanil on IOP. METHODS: Therefore, a prospective, randomized study was conducted to compare the effects on IOP of two different anesthetic techniques: one based on a total intravenous anesthesia with propofol (Group P, bolus 1.5-2.0 mg/kg, maintenance 3.0-7.0 mg/kg/h); and the other based on sevoflurane (Group S, inhalational induction, end-tidal concentration 0.7-1.2 vol.%). An infusion of remifentanil (10 microg/kg/h) was used with both techniques. In ASA I-III patients with normal IOP undergoing elective cataract surgery, using an applanation tonometer, IOP was measured contralateral to the operated eye at nine predefined time points before, during and after anesthesia. RESULTS: The two groups (n=20 each) were comparable with regard to demographic data and hemodynamic variables. Baseline IOP was 14.2+/-2.8 mmHg (Group P) and 14.1+/-2.4 mmHg (Group S; NS). During and following the induction of anesthesia, IOP was reduced in both groups. Intraocular pressure was significantly lower in Group P (6.0+/-3.2 mmHg) than in Group S (8.9+/-3.4 mmHg) during the induction of anesthesia. CONCLUSION: In patients undergoing cataract surgery under general anesthesia with tracheal intubation, anesthetic regimens with propofol as well as with sevoflurane, both combined with remifentanil, decrease IOP significantly. The decrease in IOP was significantly more pronounced in the propofol group than in the sevoflurane group.     

Prevention of atelectasis formation during the induction of general anesthesia in morbidly obese patients

Atelectasis caused by general anesthesia is increased in morbidly obese patients. We have shown that application of positive end-expiratory pressure (PEEP) during the induction of anesthesia prevents atelectasis formation in nonobese patients. We therefore studied the efficacy of PEEP in morbidly obese patients to prevent atelectasis. Twenty-three adult morbidly obese patients (body mass index >35 kg/m(2)) were randomly assigned to one of two groups. In the PEEP group, patients breathed 100% oxygen (5 min) with a continuous positive airway pressure of 10 cm H(2)O and, after the induction, mechanical ventilation via a face mask with a PEEP of 10 cm H(2)O. In the control group, the same induction was applied but without continuous positive airway pressure or PEEP. Atelectasis, determined by computed tomography, and blood gas analysis were measured twice: before the induction and directly after intubation. After endotracheal intubation, patients of the control group showed an increase in the amount of atelectasis, which was much larger than in the PEEP group (10.4% +/- 4.8% in control group versus 1.7% +/- 1.3% in PEEP group; P < 0.001). After intubation with a fraction of inspired oxygen of 1.0, PaO(2) was significantly higher in the PEEP group compared with the control group (457 +/- 130 mm Hg versus 315 +/- 100 mm Hg, respectively; P = 0.035) We conclude that in morbidly obese patients, atelectasis formation is largely prevented by PEEP applied during the anesthetic induction and is associated with a better oxygenation. IMPLICATIONS: Application of positive end-expiratory pressure during induction of general anesthesia in morbidly obese patients prevents atelectasis formation and improves oxygenation. Therefore, this technique should be considered for anesthesia induction in morbidly obese patients.     

七氟醚吸入麻醉在非住院患儿清创缝合术中的应用

目的观察七氟醚吸入麻醉在非住院患儿清创缝合术中的应用。方法年龄2~6岁ASAⅠ或Ⅱ级行清创缝合术患儿60例,随机均分为两组:七氟醚组(S组)及氯胺酮组(K组),分别采用面罩吸入七氟醚或肌肉注射氯胺酮进行麻醉诱导及维持。观察并记录两组患儿麻醉中MAP、HR、RR及SpO2的变化,记录意识消失、苏醒及麻醉恢复室(PACU)停留时间,观察并随访麻醉中及麻醉后的不良反应。结果 S组患儿术中MAP略有下降,HR无明显变化,而K组术中MAP升高、HR增快(P<0.05);S组患儿意识消失时间、苏醒时间及PACU停留时间明显短于K组(P<0.05);K组诱导期兴奋、术中体动及分泌物增加的病例数显著多于S组(P<0.05)。结论七氟醚吸入麻醉诱导迅速、维持平稳、苏醒彻底、循环呼吸影响小、不良反应发生率低、PACU停留时间短,可安全用于非住院患儿清创缝合手术麻醉。     

Economical benefit of continuous total intravenous anesthesia]

Total intravenous anesthesia (TIVA) has been recommended in view of avoiding air pollution. However, intermittent administration of anesthetic agents has a large disadvantage of delayed emergence. We reported that continuous TIVA with propofol, ketamine, vecuronium and buprenorphine (PKBp) could bring rapid emergence. In this study, we calculated and compared the cost of anesthesia in the subjects who had undergone general anesthesia either with continuous PKBp or nitrous oxide-oxygen-sevoflurane. In group PKBp subjects, after induction with propofol, ketamine, vecuronium and buprenorphine, anesthesia was maintained with continuous intravenous administration of propofol corresponding to the patient's age using twice step down method; ketamine (240 micrograms.kg-1.h-1), vecuronium (80 micrograms.kg-1.h-1) and buprenorphine (0.4 microgram.kg-1.h-1). Group GOS subjects, after the same induction method, received nitrous oxide, sevoflurane and vecuronium. Moreover, the group GOS subjects were divided to two groups; the high flow GOS (N2O:O2:sevoflurane = 4 l:2 l:30 ml) and the low flow GOS (N2O:O2:sevoflurane = 2 l:1 l:15 ml). Continuous PKBp group showed lower cost than the high flow GOS group. The PKBp group showed lower cost than the low flow GOS group except in patients weighing more than 100 kg. Furthermore, we calculated the cost of continuous PKBp anesthesia in Japan, U.S.A. and U.K. The U.S.A. cost of PKBp was higher than the Japanese and the U.K., because the cost of ketamine in U.S.A. is higher than in the other countries. Continuous PKBp is more economical than the high flow GOS, and continuous PKBp in Japan is more economical than in U.S.A.     

Intraoperative effects of combined versus general anesthesia during major liver surgery

AIM: The study compares the intraoperative effects of combined versus general anesthesia during major liver surgery. METHODS: In this prospective randomized study, 70 patients were divided into 2 group of 35 subjects. Group A received general anesthesia (thiopentone, fentanyl, vecuronium, sevoflurane in a closed circuit) 15 minutes after placement of an epidural catheter (D9-D10) and induction of epidural anesthesia (6 ml 2% naropine). Continuous epidural infusion was initiated before surgical incision and continued with 0.2% naropine (7 ml/h) until the end of the operation. Group B received combined intraoperative anesthesia wit fentanyl doses according to hemodynamic parameters and 0.1 mg/kg morphine 30-4 minutes before cutaneous suture. Hemodynamic values were measured at base line (T0), and then at 15, 30, 60, 120 and 180 minutes after induction of general anesthesia (T1, T2, T3, T4 and T5, respectively). On recovery, patients were assessed for pain at rest and on movement reported on a visual analog scale; degree of motor blockade according to the Bromage scale; appearance of side effects; use af analgesic. RESULTS: A statistically significant decrease in the mean arterial blood pressure (ABP) and heart rate (HR) was noted within each group at 15 minutes after induction of general anesthesia. Significant differences in ABP were found between the 2 groups at T1 to T5, whereas HR values were substantially similar. The mean intraoperative use of fentanyl was significantly higher in Group B than in Group A, as was that of vecuronium. Pain intensity on recovery in patients who received epidural anesthesia was lower both at rest and on movement; only the patients in Group B required additional analgesics. No motor blockade was observed in either group. Nausea and vomiting were more frequent in Group B; hypotension was more frequent in Group A. CONCLUSION: The study confirms the safety of locoregional anesthesia in liver surgery, with good hemodynamic stability and absence of major side effects. The lower intraoperative use of opioids and muscle relaxants in patients who received epidural anesthesia confirms the neurovegetative protection this method provides. The data support the hypothesis that greater intraoperative use of opioids may be responsible for the higher incidence of side effects. Therefore, the intraoperative use of combined low-concentration anesthetic agents alone appears to offer a reasonable treatment option that provides adequate pain control at recovery from general anesthesia, with only minor side effects typically associated with analgesic (motor blockade) and opioids (nausea and vomiting). Given the complications associated with the technique, it should be performed by an expert anesthetist.     

Recovery profile, costs, and patient satisfaction with propofol and sevoflurane for fast-track office-based anesthesia.

BACKGROUND: Office-based surgery is becoming increasingly popular because of its cost-saving potential Both propofol and sevoflurane are commonly used in the ambulatory setting because of their favorable recovery profiles. This clinical investigation was designed to compare the clinical effects, recovery characteristics, and cost-effectiveness of propofol and sevoflurane when used alone or in combination for office-based anesthesia. METHODS: One hundred four outpatients undergoing superficial surgical procedures at an office-based surgical center were randomly assigned to one of three general anesthetic groups. In groups I and II, propofol 2 mg/kg was administered for induction followed by propofol 75-150 microg x kg(-1) x min(-1) (group I) or sevoflurane 1-2% (group II) with N2O 67% in oxygen for maintenance of anesthesia In group m, anesthesia was induced and maintained with sevoflurane in combination with N2O 67% in oxygen. Local anesthetics were injected at the incision site before skin incision and during the surgical procedure. The recovery profiles, costs of drugs, and resources used, as well as patient satisfaction, were compared among the three treatment groups. RESULTS: Although early recovery variables (e.g., eye opening, response to commands, and sitting up) were similar in all three groups, the times to standing up and to be "home ready" were significantly prolonged when sevoflurane-N2O was used for both induction and maintenance of anesthesia. The time to tolerating fluids, recovery room stay, and discharge times were significantly decreased when propofol was used for both induction and maintenance of anesthesia. Similarly, the incidence of postoperative nausea and vomiting and the need for rescue antiemetics were also significantly reduced after propofol anesthesia. Finally, the total costs and patient satisfaction were more favorable when propofol was used for induction and maintenance of office-based anesthesia CONCLUSION: Compared with sevoflurane-N2O, use of propofol-N2O for office-based anesthesia was associated with an improved recovery profile, greater patient satisfaction, and lower costs. There were significantly more patients who were dissatisfied with the sevoflurane anesthetic technique.     

Severity of airway hyperreactivity associated with laryngeal mask airway removal: correlation with volatile anesthetic choice and depth of anesthesia.

STUDY OBJECTIVE: To compare the influence of anesthetic depth and choice of volatile anesthetic drug on the incidence and severity of airway hyperreactivity associated with Laryngeal Mask Airway (LMA) removal. DESIGN: Randomized observer-blinded study. SETTING: Ambulatory Surgical Center at a University Medical Center. PATIENTS: 123 ASA physical status I and II children undergoing infraumbilical procedures. INTERVENTIONS: Patients were randomly assigned to one of four treatment groups: Group 1 = anesthetic induction with halothane, maintenance with isoflurane, nitrous oxide (N(2)O), and oxygen (O(2)), LMA removed when child awakened; Group 2 =anesthetic induction and maintenance as in Group 1, LMA removed while child anesthetized with age adjusted 2 minimum alveolar concentration (MAC) end-tidal concentration of isoflurane; Group 3 = anesthetic induction and maintenance with sevoflurane, N(2)O, and O(2), LMA removed when child awakened; Group 4 = anesthetic induction and maintenance as in Group 3, but LMA removed while child anesthetized with age-adjusted 2 MAC end-tidal concentration of sevoflurane. MEASUREMENTS AND MAIN RESULTS: Severity of airway hyperreactivity was graded as mild, moderate, or severe. A significant difference was not found amongst the four groups with respect to mild and moderate airway hyperreactivity. Severe airway hyperreactivity leading to a critical event [partial or complete laryngospasm with oxygen saturation (SPO(2)) < 85%] was only encountered in Group 1 patients (incidence 13%). Adverse airway events (SPO(2) < 90%, vomiting and bronchospasm) were also significantly higher in Group 1 (p < 0.05). Isoflurane use was independently associated with significantly higher airway hyperreactivity when compared with sevoflurane (p < 0.05). CONCLUSIONS: Depth of anesthesia during LMA removal does not appear to affect the incidence or severity of airway hyperreactivity when sevoflurane is the maintenance anesthetic. However, awake LMA removal during isoflurane anesthesia results in a higher incidence of adverse airway events and carries the risk of severe airway hyperreactivity.     

A cost comparison of methohexital and propofol for ambulatory anesthesia.

Methohexital is eliminated more rapidly than thiopental, and early recovery compares favorably with propofol. We designed this study to evaluate the recovery profile when methohexital was used as an alternative to propofol for the induction of anesthesia before either sevoflurane or desflurane in combination with nitrous oxide. One hundred twenty patients were assigned randomly to one of four anesthetic groups: (I) methohexital-desflurane, (II) methohexital-sevoflurane, (III) propofol-desflurane, or (IV) propofol-sevoflurane. Recovery times after the anesthetic drugs, as well as the perioperative side effect profiles, were similar in all four groups. A cost-minimization analysis revealed that methohexital was less costly for the induction of anesthesia. At the fresh gas flow rates used during this study, the costs of the volatile anesthetics for maintenance of anesthesia did not differ among the four groups. However, at low flow rates (< or = 1 L/min), the methohexital-desflurane group would have been the least expensive anesthetic technique. In conclusion, methohexital is a cost-effective alternative to propofol for the induction of anesthesia in the ambulatory setting. At low fresh gas flow rates, the methohexital-desflurane combination was the most cost-effective for the induction and maintenance of general anesthesia. Implications: Using methohexital as an alternative to propofol for the induction of anesthesia for ambulatory surgery seems to reduce drug costs. When fresh gas flow rates < or = 1 L/min are used, the combination of methohexital for the induction and desflurane for maintenance may be the most cost-effective general anesthetic technique for ambulatory surgery.     

The effect of anesthetic technique on early postoperative gastric emptying: comparison of propofol-remifentanil and opioid-free sevoflurane anesthesia

Purpose A postoperative decrease in the gastric emptying (GE) rate may delay the early start of oral feeding and alter the bioavailability of orally administered drugs. The aim of this study was to compare the effect on early gastric emptying between two anesthetic techniques. Methods Fifty patients (age, 19–69 years) undergoing day-case laparascopic cholecystectomy were randomly assigned to received either total intravenous anesthesia with propofol/remifentanil/rocuronium (TIVA; n = 25) or inhalational opioid-free anesthesia with sevoflurane/rocuronium (mask induction; GAS; n = 25). Postoperative gastric emptying was evaluated by the acetaminophen method. After arrival in the recovery unit, acetaminophen (paracetamol) 1.5 g was given through a nasogastric tube, and blood samples were drawn during a 2-h period. The area under the serum-acetaminophen concentration curve from 0–60 min (AUC₆₀), the maximal concentration (C_max), and the time to reach C-max (T_max) were calculated. Results Twelve patients were excluded due to surgical complications (e.g., conversion to open surgery) and difficulty in drawing blood samples (TIVA, n = 7; GAS, n = 5). Gastric emptying parameters were (mean ± SD): TIVA, AUC60, 2458 ± 2775 min·μmol·l⁻¹; Cmax, 71 ± 61 μmol·l⁻¹; and Tmax, 81 ± 37 min; and GAS, AUC60, 2059 ± 2633 min·μmol·l⁻¹; Cmax, 53 ± 53 μmol·l⁻¹; and Tmax, 83 ± 41 min. There were no significant differences between groups. Conclusion There was no major difference in early postoperative gastric emptying between inhalation anesthesia with sevoflurane versus total intravenous anesthesia with propofol-remifentanil. Both groups showed a pattern of delayed gastric emptying, and the variability in gastric emptying was high. Perioperative factors other than anesthetic technique may have more influence on gastric emptying.     

丙泊酚与七氟醚对结直肠癌根治术患者缺氧诱导因子-1水平的影响

探讨丙泊酚与七氟醚对结直肠癌根治术患者围手术期血清缺氧诱导因子-1（hypoxia inducible factor-1, HIF-1）的影响。 方法 选择符合纳入标准结直肠癌根治术患者40例,采用随机数字表法分为两组：丙泊酚组（P组）和七氟醚组（S组）,每组20例。P组采用全凭静脉全身麻醉,常规静脉诱导,靶控输注（target-controlled infusion, TCI）丙泊酚,术中维持：瑞芬太尼TCI、丙泊酚TCI。S组采用静吸复合全身麻醉,常规静脉诱导,术中维持：瑞芬太尼TCI、七氟醚吸入。于麻醉前30 min（T0）、手术结束即刻（T1）、术后24 h（T2）时采集患者颈内静脉血样4 ml,采用双抗体夹心ELISA法检测HIF-1血清浓度。 结果 P组T1时点HIF-1浓度小于T0时点,差异有统计学意义（P＜0.05）。S组T1时点HIF-1浓度大于T0时点,差异有统计学意义（P＜0.05）。与P组比较,S组T1时点HIF-1浓度升高（P＜0.05）。 结论 丙泊酚可以使结直肠癌患者血清HIF？蛳1的浓度降低,而七氟醚上调其表达水平,提示丙泊酚更适用于此类患者,对肿瘤后期治疗及康复有意义。     

Comparative study of 3 techniques for total intravenous anesthesia: midazolam-ketamine, propofol-ketamine, and propofol-fentanyl]

OBJECTIVE: To compare the characteristics of induction, maintenance and awakening for three techniques of combined total intravenous anesthesia (TIVA): propofol-ketamine, midazolam-ketamine and propofol-fentanyl. PATIENTS AND METHODS: Sixty patients were randomly assigned to three TIVA groups. Group 1 (n = 20) received midazolam, ketamine and vecuronium. Group 2 (n = 20) received propofol, ketamine and vecuronium. Group 3 (n = 20) received propofol, fentanyl and vecuronium. The variables compared were hemodynamic changes during induction and maintenance and upon awakening; time until awakening; and the incidence of postanesthetic complications. We also assessed whether propofol was better than midazolam at preventing the psychomimetic effects of ketamine. RESULTS: The demographic characteristics of the three groups were similar. Hemodynamic variables were most stable in group 2. Perfusion of midazolam-ketamine was accompanied by a significantly higher number of hypertensive peaks. Time to awakening was significantly shorter in Group I (11.8 +/- 5 min) than in group 2 (20.2 +/- 12.5 min); in group 2 time to awakening was 16.6 +/- 5.6 min. Eight patients in group 1, 5 in group 2 and 1 in group 3 reported having bad dreams, the difference between groups 1 and 3 reaching statistical significance. No patient experienced hallucinations and all reported satisfaction with the anesthetic technique used. CONCLUSIONS: TIVA with ketamine and propofol is comparable to the most commonly used combination of propofol and fentanyl and may be an appropriate choice when hemodynamic stability is of great importance; withdrawal 15 min before ending surgery prevents prolonged awakening. Perfusion of midazolam-ketamine is not recommendable for scheduled surgery because it induces too many hypertensive peaks. Although neither midazolam nor propofol completely prevents the psychomimetic effects of ketamine, such effects are not so severe that patients reject the anesthetic technique used.     

Emergence and recovery characteristics of desflurane versus sevoflurane in morbidly obese adult surgical patients: a prospective, randomized study

We compared postoperative recovery after desflurane (n = 25) versus sevoflurane (n = 25) anesthesia in morbidly obese adults (body mass index >/=35) who underwent gastrointestinal bypass surgery via an open laparotomy. After premedication with midazolam and metoclopramide 1 h before surgery, epidural catheter placement, induction of anesthesia with fentanyl and propofol, and tracheal intubation facilitated with succinylcholine, anesthesia was maintained with age-adjusted 1 minimum alveolar concentration (MAC) desflurane or sevoflurane. Fentanyl IV, morphine or local anesthetics epidurally, and vasoactive drugs as needed were used to maintain arterial blood pressure at +/-20% of baseline value and to keep bispectral index of the electroencephalogram values between 40 to 60 U. Although patients were anesthetized with desflurane for a longer time (261 +/- 50 min versus 234 +/- 37 min, mean +/- sd; P < 0.05, desflurane versus sevoflurane, respectively) and for more MAC-hours (4.2 +/- 0.9 h versus 3.7 +/- 0.8 h; P < 0.05), significantly earlier recovery of response to command and tracheal extubation occurred in patients given desflurane than in patients given sevoflurane. The modified Aldrete score was greater in desflurane-anesthetized patients on admission to the postanesthesia care unit (PACU) (P = 0.01) but not at discharge (P = 0.47). On admission to PACU, patients given desflurane had higher oxygen saturations (97.0% +/- 2.4%) than patients given sevoflurane (94.8% +/- 4.4%, P = 0.035). Overall, the incidence of postoperative nausea and vomiting and the use of antiemetics did not differ between the two anesthetic groups. We conclude that morbidly obese adult patients who underwent major abdominal surgery in a prospective, randomized study awoke significantly faster after desflurane than after sevoflurane anesthesia and the patients anesthetized with desflurane had higher oxygen saturation on entry to the PACU.