The complexity of recovery from anesthesia

Society of Anesthesia and Sleep Medicine Guideline on Intraoperative Management of Adult Patients With Obstructive Sleep Apnea

The purpose of the Society of Anesthesia and Sleep Medicine Guideline on Intraoperative Management of Adult Patients With Obstructive Sleep Apnea (OSA) is to present recommendations based on current scientific evidence. This guideline seeks to address questions regarding the intraoperative care of patients with OSA, including airway management, anesthetic drug and agent effects, and choice of anesthesia type. Given the paucity of high-quality studies with regard to study design and execution in this perioperative field, recommendations were to a large part developed by subject-matter experts through consensus processes, taking into account the current scientific knowledge base and quality of evidence. This guideline may not be suitable for all clinical settings and patients and is not intended to define standards of care or absolute requirements for patient care; thus, assessment of appropriateness should be made on an individualized basis. Adherence to this guideline cannot guarantee successful outcomes, but recommendations should rather aid health care professionals and institutions to formulate plans and develop protocols for the improvement of the perioperative care of patients with OSA, considering patient-related factors, interventions, and resource availability. Given the groundwork of a comprehensive systematic literature review, these recommendations reflect the current state of knowledge and its interpretation by a group of experts at the time of publication. While periodic reevaluations of literature are needed, novel scientific evidence between updates should be taken into account. Deviations in practice from the guideline may be justifiable and should not be interpreted as a basis for claims of negligence.

Anaesthetic management for balloon dilation of cor triatriatum dexter in a dog

A three-month-old female Rottweiler puppy was referred for intravascular correction of a previously identified cor triatriatum dexter. Echocardiography confirmed the presence of a hyperechoic membrane that divided the right atrium into a cranial and caudal chamber. A foramen in this membrane allowed the blood to flow from the caudal to the cranial chamber. Balloon dilation of the defect under transthoracic echocardiographic guidance was scheduled for the following day. The dog was premedicated with 0.5 μg/kg sufentanil and 0.2 mg/kg midazolam administered intravenously. General anaesthesia was induced with 2 mg/kg propofol and maintained with inhaled isoflurane in oxygen; at the same time, a constant rate infusion of 0.5 μg/kg/h sufentanil was administered by means of an infusion pump. Uneventful ventricular and supraventricular tachyarrhythmias developed during the placement of catheters and balloon dilation. At the end of procedure, when the guide wire and balloon catheter were removed, normal sinus rhythm was observed. To the authors’ knowledge, no previous reports have described the anaesthetic management of a balloon dilation procedure for cor triatriatum dexter in dogs.

Postoperative recovery after anesthesia in morbidly obese patients: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Obese patients present a challenge to safe general anesthesia because of impaired cardiopulmonary physiology and increased risks of aspiration and acute upper airway obstruction. Since studies are lacking regarding the postoperative effects on recovery from general anesthesia in morbidly obese patients, we conducted a systematic review and meta-analysis of recovery outcomes in morbidly obese patients who had undergone general anesthesia.

SOURCE

We systematically searched the PubMed, EMBASE™, Cochrane, and Scopus™ databases for randomized controlled trials that evaluated the outcome of anesthesia with desflurane, sevoflurane, isoflurane, or propofol in morbidly obese patients. Using a random effects model, we conducted meta-analyses to assess recovery times (eye opening, hand squeezing, tracheal extubation, and stating name or birth date), time to discharge from the postanesthesia care unit (PACU), and the incidence and severity of postoperative nausea and vomiting (PONV).

PRINCIPAL FINDINGS

We reviewed results for 11 trials and found that patients given desflurane took less time: to respond to commands to open their eyes (weighted mean difference [WMD] -3.10 min; 95% confidence interval (CI): -5.13 to -1.08), to squeeze the investigator's hand (WMD -7.83 min; 95% CI: -8.81 to -6.84), to be prepared for tracheal extubation (WMD -3.88 min; 95% CI: -7.42 to -0.34), and to state their name (WMD -7.15 min; 95% CI: -11.00 to -3.30). We did not find significant differences in PACU discharge times, PONV, or the PACU analgesic requirement.

CONCLUSION

Postoperative recovery was significantly faster after desflurane than after sevoflurane, isoflurane, or propofol anesthesia in obese patients. No clinically relevant differences were observed regarding PACU discharge time, incidence of PONV, or postoperative pain scores. The systematic review was registered with PROSPERO (CRD42014009480).

Increased lung clearance of isoflurane shortens emergence in obesity: a prospective randomized-controlled trial

BACKGROUND

There is a concern that obesity may play a role in prolonging emergence from fat-soluble inhalational anaesthetics. We hypothesized that increased pulmonary clearance of isoflurane will shorten immediate recovery from anaesthesia and post-anaesthesia care unit (PACU) stay in obese patients.

METHODS

After Ethics Review Board approval, 44 ASA I-III patients with BMI>30 kg/m(2) undergoing elective gynaecological or urological surgery were randomized after completion of surgery to either an isocapnic hyperpnoea (IH) or a conventional recovery (C) group. The anaesthesia protocol included propofol, fentanyl, morphine, rocuronium and isoflurane in air/O(2) . Groups were compared using unpaired t-test and ANOVA.

RESULTS

Minute ventilation in the IH group before extubation was 22.6 ± 2.7 vs. 6.3 ± 1.8 l/min in the C group. Compared with C, the IH group had a shorter time to extubation (5.4 ± 2.7 vs. 15.8 ± 2.7 min, P<0.01), initiation of spontaneous ventilation (2.7 ± 2.3 vs. 6.5 ± 4.5 min, P<0.01), BIS recovery >75 (3.2 ± 2.3 vs. 8.9 ± 5.8 min, P<0.01), eye opening (4.6 ± 2.9 vs. 13.6 ± 7.1 min, P<0.01) and eligibility for leaving the operating room (7.1 ± 2.9 vs. 19.9 ± 11.9 min, P<0.01). There was no difference in time for eligibility for PACU discharge.

CONCLUSION

Increasing alveolar ventilation enhances anaesthetic elimination and accelerates short-term recovery in obese patients.

A comparison of the duration and quality of recovery from isoflurane, sevoflurane and desflurane anaesthesia in dogs undergoing magnetic resonance imaging

OBJECTIVE

To compare the recovery after anaesthesia with isoflurane, sevoflurane and desflurane in dogs undergoing magnetic resonance imaging (MRI) of the brain.

STUDY DESIGN

Prospective, randomized clinical trial.

ANIMALS

Thirty-eight dogs weighing 23.7 +/- 12.6 kg.

METHODS

Following pre-medication with meperidine, 3 mg kg(-1) administered intramuscularly, anaesthesia was induced intravenously with propofol (mean dose 4.26 +/- 1.3 mg kg(-1)), the trachea was intubated, and an inhalational anaesthetic agent was administered in oxygen. The dogs were randomly allocated to one of three groups: group I (n = 13) received isoflurane, group S (n = 12) received sevoflurane and group D (n = 13) received desflurane. Parameters recorded included cardiopulmonary data, body temperature, end-tidal anaesthetic concentration, duration of anaesthesia, and recovery times and quality. Qualitative data were compared using chi-squared and Fisher's exact tests and quantitative data with anova and Kruskal-Wallis test. Post-hoc comparisons for quantitative data were undertaken with the Mann-Whitney U-test.

RESULTS

The duration of anaesthesia [mean and standard deviation (SD)] in group I was: 105.3 (27.48) minutes, group S: 120.67 (19.4) minutes, and group D: 113.69 (26.68) minutes (p = 0.32). Times to extubation [group I: 8 minutes, (interquartile range 6-9.5), group S: 7 minutes (IQR 5-7), group D: 5 minutes (IQR 3.5-7), p = 0.017] and to sternal recumbency [group I: 11 minutes (IQR 9.5-13.5), group S: 9.5 minutes (IQR 7.25-11.75), group D: 7 minutes (range 3.5-11.5), p = 0.048] were significantly different, as were times to standing. One dog, following sevoflurane, had an unacceptable quality of recovery, but most other recoveries were calm, with no significant difference between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

All three agents appeared suitable for use. Dogs' tracheas were extubated and the dogs recovered to sternal recumbency most rapidly after desflurane. This may be advantageous for animals with some neurological diseases and for day case procedures.

Depth of anaesthesia monitoring in obese patients: a randomized study of propofol-remifentanil

BACKGROUND

In obese patients, depth of anaesthesia monitoring could be useful in titrating intravenous anaesthetics. We hypothesized that depth of anaesthesia monitoring would reduce recovery time and use of anaesthetics in obese patients receiving propofol and remifentanil.

METHODS

We investigated 38 patients with a body mass index >or=30 kg/m(2) scheduled for an abdominal hysterectomy. Patients were randomized to either titration of propofol and remifentanil according to a cerebral state monitor (CSM group) or according to usual clinical criteria (control group). The primary end point was time to eye opening and this was assessed by a blinded observer.

RESULTS

Time to eye opening was 11.8 min in the CSM group vs. 13.4 min in the control group (P=0.58). The average infusion rate for propofol was a median of 516 vs. 617 mg/h (P=0.24) and for remifentanil 2393 vs. 2708 microg/h (P=0.04). During surgery, when the cerebral state index was continuously between 40 and 60, the corresponding optimal propofol infusion rate was 10 mg/kg/h based on ideal body weight.

CONCLUSION

No significant reduction in time to eye opening could be demonstrated when a CSM was used to titrate propofol and remifentanil in obese patients undergoing a hysterectomy. A significant reduction in remifentanil consumption was found.

Desflurane versus sevoflurane for laparoscopic gastroplasty in morbidly obese patients

STUDY OBJECTIVE

To determine if desflurane results in a faster emergence as measured by time to eye opening compared to sevoflurane in morbidly obese patients undergoing laparoscopic gastroplasty.

STUDY DESIGN

Prospective, randomized, double-blinded study.

SETTING

Tertiary care hospital.

PATIENTS

70 patients with a body mass index of 35 or higher undergoing laparoscopic gastroplasty.

INTERVENTIONS

Patients were randomized into two groups to receive either desflurane or sevoflurane for maintenance of general anesthesia.

MEASUREMENTS

Intraoperative measured variables included the time from when the inhalation agent was turned off (no agent delivered) to eye opening and the time from when the inhalation agent was turned off to extubation. Postanesthesia care unit (PACU)-measured variables on admission and at 15 minute intervals until discharge included oxygen saturation (Spo2), blood pressure, heart rate, pain and nausea Visual Analog Scale (VAS) scores, emesis, modified Aldrete score, and Mini-Mental Status (MMS) examination score.

MAIN RESULTS

No differences were noted in demographic data, total surgical operative time, times from turning inhalation agent off to eye opening and extubation, or average length of stay in PACU. No differences were noted with respect to pain VAS, treatment for pain, modified Aldrete scores, emesis, or treatment for postoperative nausea or emesis. Differences were noted in PACU nausea VAS at 15 minutes, PACU nausea VAS at discharge, and PACU-MMS score at 45 minutes; however, multivariate analysis of variance revealed no differences between groups over the repeated PACU measured time periods in nausea VAS (P=0.17) or in MMS (P=0.34). Higher heart rates in the desflurane group were observed during PACU admission (82.3+/-9.8 vs 74.4+/-13.4 bpm, P<0.01) and 15 minutes post PACU admission (79.4+/-12.1 vs 71.3+/-13.2 bpm, P=0.01).

CONCLUSIONS

In morbidly obese patients undergoing laparoscopic gastroplasty, emergence, as measured by time to eye opening, did not differ between desflurane and sevoflurane, with similar recovery characteristics.