Use of propofol for office-based anesthesia: effect of nitrous oxide on recovery profile

Perioperative Care of Elderly Surgical Outpatients

The ambulatory setting offers potential advantages for elderly patients undergoing elective surgery due to the advancement in both surgical and anesthetic techniques resulting in quicker recovery times, fewer complications, higher patient satisfaction, and reduced costs of care. This review article aims to provide a practical guide to anesthetic management of elderly outpatients. Important considerations in the preoperative evaluation of elderly outpatients with co-existing diseases, as well as the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and recommendations regarding the management of common postoperative complications (e.g., pain, postoperative nausea and vomiting [PONV], delirium and cognitive dysfunction, and gastrointestinal dysfunction) are discussed. The role of anesthesiologists as perioperative physicians is important for optimizing surgical outcomes for elderly patients undergoing ambulatory surgery. The implementation of high-quality, evidence-based perioperative care programs for the elderly on an ambulatory basis has assumed increased importance. Optimal management of perioperative pain using opioid-sparing multimodal analgesic techniques and preventing PONV using prophylactic antiemetics are key elements for achieving enhanced recovery after surgery.

Office-based anesthesia: safety and outcomes

The increasing volume of office-based medical and surgical procedures has fostered the emergence of office-based anesthesia (OBA), a subspecialty within ambulatory anesthesia. The growth of OBA has been facilitated by numerous trends, including innovations in medical and surgical procedures and anesthetic drugs, as well as improved provider reimbursement and greater convenience for patients. There is a lack of randomized controlled trials to determine how office-based procedures and anesthesia affect patient morbidity and mortality. As a result, studies on this topic are retrospective in nature. Some of the early literature broaches concerns about the safety of office-based procedures and anesthesia. However, more recent data have shown that care in ambulatory settings is comparable to hospitals and ambulatory surgery centers, especially when offices are accredited and their proceduralists are board-certified. Office-based suites can continue to enhance the quality of care that they deliver to patients by engaging in proper procedure and patient selection, provider credentialing, facility accreditation, and incorporating patient safety checklists and professional society guidelines into practice. These strategies aiming at patient morbidity and mortality in the office setting will be increasingly important as more states, and possibly the federal government, exercise regulatory authority over the ambulatory setting. We explore these trends, their implications for patient safety, strategies for minimizing patient complications and mortality in OBA, and future developments that could impact the field.

Nitrous oxide-related postoperative nausea and vomiting depends on duration of exposure

BACKGROUND

Inclusion of nitrous oxide in the gas mixture has been implicated in postoperative nausea and vomiting (PONV) in numerous studies. However, these studies have not examined whether duration of exposure was a significant covariate. This distinction might affect the future place of nitrous oxide in clinical practice.

METHODS

PubMed listed journals reporting trials in which patients randomized to a nitrous oxide or nitrous oxide-free anesthetic for surgery were included, where the incidence of PONV within the first 24 postoperative hours and mean duration of anesthesia was reported. Meta-regression of the log risk ratio for PONV with nitrous oxide (lnRR PONVN2O) versus duration was performed.

RESULTS

Twenty-nine studies in 27 articles met the inclusion criteria, randomizing 10,317 patients. There was a significant relationship between lnRR PONVN2O and duration (r = 0.51, P = 0.002). Risk ratio PONV increased 20% per hour of nitrous oxide after 45 min. The number needed to treat to prevent PONV by avoiding nitrous oxide was 128, 23, and 9 where duration was less than 1, 1 to 2, and over 2 h, respectively. The risk ratio for the overall effect of nitrous oxide on PONV was 1.21 (CIs, 1.04-1.40); P = 0.014.

CONCLUSIONS

This duration-related effect may be via disturbance of methionine and folate metabolism. No clinically significant effect of nitrous oxide on the risk of PONV exists under an hour of exposure. Nitrous oxide-related PONV should not be seen as an impediment to its use in minor or ambulatory surgery.

Does anaesthesia with nitrous oxide affect mortality or cardiovascular morbidity? A systematic review with meta-analysis and trial sequential analysis

BACKGROUND

The role of nitrous oxide in modern anaesthetic practice is contentious. One concern is that exposure to nitrous oxide may increase the risk of cardiovascular complications. ENIGMA II is a large randomized clinical trial currently underway which is investigating nitrous oxide and cardiovascular complications. Before the completion of this trial, we performed a systematic review and meta-analysis, using Cochrane methodology, on the outcomes that make up the composite primary outcome.

METHODS

We used conventional meta-analysis and trial sequential analysis (TSA). We reviewed 8282 abstracts and selected 138 that fulfilled our criteria for study type, population, and intervention. We attempted to contact the authors of all the selected publications to check for unpublished outcome data.

RESULTS

Thirteen trials had outcome data eligible for our outcomes. We assessed three of these trials as having a low risk of bias. Using conventional meta-analysis, the relative risk of short-term mortality in the nitrous oxide group was 1.38 [95% confidence interval (CI) 0.22-8.71] and the relative risk of long-term mortality in the nitrous oxide group was 0.94 (95% CI 0.80-1.10). In both cases, TSA demonstrated that the data were far too sparse to make any conclusions. There were insufficient data to perform meta-analysis for stroke, myocardial infarct, pulmonary embolus, or cardiac arrest.

CONCLUSION

This systematic review demonstrated that we currently do not have robust evidence for how nitrous oxide used as part of general anaesthesia affects mortality and cardiovascular complications.

Perioperative care for the older outpatient undergoing ambulatory surgery

As the number of ambulatory surgery procedures continues to grow in an aging global society, the implementation of evidence-based perioperative care programs for the elderly will assume increased importance. Given the recent advances in anesthesia, surgery, and monitoring technology, the ambulatory setting offers potential advantages for elderly patients undergoing elective surgery. In this review article we summarize the physiologic and pharmacologic effects of aging and their influence on anesthetic drugs, the important considerations in the preoperative evaluation of elderly outpatients with coexisting diseases, the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and offer recommendations regarding the management of common postoperative side effects (including delirium and cognitive dysfunction, fatigue, dizziness, pain, and gastrointestinal dysfunction) after ambulatory surgery. We conclude with a discussion of future challenges related to the growth of ambulatory surgery practice in this segment of our surgical population. When information specifically for the elderly population was not available in the peer-reviewed literature, we drew from relevant information in other ambulatory surgery populations.

Fast-track anesthetic techniques for ambulatory surgery

PURPOSE OF REVIEW

Improving perioperative efficiency and throughput has become increasingly important in facilitating the fast-track recovery process following ambulatory surgery. This review focuses on the important role played by the anesthesiologist as a perioperative physician in fast-track ambulatory surgery.

RECENT FINDINGS

A literature review of more than 200 peer-reviewed publications was used to develop evidence-based recommendations for optimizing recovery following ambulatory anesthesia. The choice of anesthetic technique should be tailored to the needs of the patient as well as the type of surgical procedure being performed in the ambulatory setting. The anesthetic decisions made by the anesthesiologist, as a key perioperative physician, are of critical importance in developing a successful fast-track ambulatory surgery program.

SUMMARY

The pivotal role played by the anesthesiologist as the key perioperative physician in facilitating the recovery process has assumed increased importance in the current outpatient fast-track recovery environment. The choice of premedication, anesthetic, analgesic and antiemetic drugs, as well as cardiovascular, hormonal and fluid therapies, can all influence the ability to fast-track outpatients after ambulatory surgery.

The Role of the Anesthesiologist in Fast-Track Surgery: From Multimodal Analgesia to Perioperative Medical Care

BACKGROUND

Improving perioperative efficiency and throughput has become increasingly important in the modern practice of anesthesiology. Fast-track surgery represents a multidisciplinary approach to improving perioperative efficiency by facilitating recovery after both minor (i.e., outpatient) and major (inpatient) surgery procedures. In this article we focus on the expanding role of the anesthesiologist in fast-track surgery.

METHODS

A multidisciplinary group of clinical investigators met at McGill University in the Fall of 2005 to discuss current anesthetic and surgical practices directed at improving the postoperative recovery process. A subgroup of the attendees at this conference was assigned the task of reviewing the peer-reviewed literature on this topic as it related to the role of the anesthesiologist as a perioperative physician.

RESULTS

Anesthesiologists as perioperative physicians play a key role in fast-track surgery through their choice of preoperative medication, anesthetics and techniques, use of prophylactic drugs to minimize side effects (e.g., pain, nausea and vomiting, dizziness), as well as the administration of adjunctive drugs to maintain major organ system function during and after surgery.

CONCLUSION

The decisions of the anesthesiologist as a key perioperative physician are of critical importance to the surgical care team in developing a successful fast-track surgery program.

Nitrous Oxide Does Not Aggravate Postoperative Emesis After Orthognathic Surgery in Female and Nonsmoking Patients

PURPOSE

The purpose of this study was to evaluate the effect of supplemental nitrous oxide on postoperative nausea and vomiting (PONV) after propofol anesthesia for orthognathic surgery in female and nonsmoking patients.

PATIENTS AND METHODS

We compared PONV in 28 ASA-I female nonsmoking patients undergoing orthognathic surgery. Anesthesia was induced with propofol combined with fentanyl, and tracheal intubation was facilitated with vecuronium. Anesthesia was maintained with propofol with or without nitrous oxide. No patient received neostigmine. PONV was assessed as score 0 (no PONV), score 1 (nausea), and score 2 (vomiting) during the 24-hour recovery period.

RESULTS

There were no differences in the patients' characteristics, operation, anesthesia and emergence time, fluid transfusion, blood loss, urine output, and total propofol and fentanyl doses between the 2 groups. There was also no difference in PONV score in 2 groups. Only 1 patient in each group vomited.

CONCLUSIONS

It is suggested that supplemental nitrous oxide does not aggravate PONV after propofol anesthesia for orthognathic surgery in female nonsmoking patients.

Anaesthesia in day case laparoscopic female sterilization: a comparison of two anaesthetic methods

BACKGROUND

Laparoscopic sterilization (LS) in women is a procedure frequently carried out in a day case setting. The purpose of the study was to measure postoperative pain, nausea and vomiting (PONV), the incidence of unplanned overnight admissions and patient satisfaction with two different anaesthetic methods.

METHODS

From August 1997 to January 1999 the LS patients were anaesthetized with propofol + fentanyl/alfentanil, N2O and atracurium, and from January 1999 to end of 2001 they were given TIVA with propofol + remifentanil. Postoperative pain was managed with standardized high doses of paracetamol and NSAID in both groups. Data were collected from hospital records and from questionnaires given to all the patients.

RESULTS

Six hundred and eighty-one women were sterilized. There were no significant differences in postoperative pain between the two groups, with 8.2 and 12.1 per cent, respectively, experiencing severe pain. Significantly fewer patients experienced moderate or severe postoperative nausea after the introduction of remifentanil anaesthesia (3.3 vs. 11.7%, P = 0.001). Eleven patients (1.8%) were admitted overnight, with no difference between the two groups. 94.5% and 96.3% of the patients were either satisfied or very satisfied with their treatment (P = 0.50).

CONCLUSION

Both anaesthetic methods provide equally good postoperative pain relief, few unplanned admissions and a high degree of patient satisfaction when combined with postoperative paracetamol and NSAID. Patients anaesthetized with remifentanil and propofol have less postoperative nausea.

Intravenous techniques in ambulatory anesthesia

The growing importance of ambulatory surgery during the past decade has led to the development of efficient anesthetic techniques in terms of quality and safety of anesthesia and recovery. In these challenging objectives, intravenous techniques have played an important role, as they provide safe, efficient, and cost-effective anesthesia in the ambulatory setting. Among the numerous intravenous drugs, propofol, with its fast and smooth onset of action, short duration of action, and low incidence of postoperative side effects appears to be the anesthetic of choice in this situation. The recent development of new techniques of administration (such as TCI, monitored anesthesia care, or patient-controlled sedation) and monitoring (such as the BIS and the availability of "hit and run" drugs such as remifentanil) will optimize intraoperative conditions and recovery, thus allowing faster home readiness in the ambulatory setting.

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.

Propofol-ketamine versus propofol-fentanyl for outpatient laparoscopy: comparison of postoperative nausea, emesis, analgesia, and recovery

STUDY OBJECTIVE

To compare postoperative nausea, emesis, analgesia, and recovery between propofol-ketamine and propofol-fentanyl in outpatient laparoscopic tubal ligations with general anesthesia.

STUDY DESIGN

Prospective, randomized, blinded study.

SETTING

Tertiary-care women's hospital.

PATIENTS

120 ASA physical status I and II ambulatory patients scheduled for elective laparoscopic tubal ligation.

INTERVENTIONS

Patients were randomized to two groups to receive either ketamine (1-1.5 mg/kg) or fentanyl (3-5 microg/kg).

MEASUREMENTS

Measured variables included total dose of ketamine, fentanyl, propofol, and operating time. Vital signs, pain visual analog scale scores (VAS), nausea VAS, presence of emesis, treatment for nausea and vomiting, pruritus, sedation, and presence of dreaming were recorded on postanesthesia care unit (PACU) admission, PACU discharge, stepdown unit admission, and hospital discharge. Results are expressed as means +/- SD or medians and analyzed using t-test, Chi-square, or Mann-Whitney (p < 0.05).

MAIN RESULTS

No differences were noted with respect to propofol dose, operating times, pain or nausea VAS scores, emesis, treatment for nausea and vomiting, pruritus, and sedation on PACU admission, PACU discharge, stepdown unit admission, and hospital discharge. The ketamine group had a higher heart rate, required more pain medication, and had a higher frequency of dreaming on PACU admission than the fentanyl group. These differences became insignificant on PACU discharge.

CONCLUSIONS

For outpatient laparoscopic tubal ligations with general anesthesia, propofol-ketamine does not improve postoperative nausea, emesis, analgesia or recovery compared with the propofol-fentanyl combination.

Fast-tracking after ambulatory surgery

The fast-tracking recovery concept examines different paradigms for streamlining the postoperative recovery process. Fast-tracking anesthetic techniques allow suitable outpatients to be discharged earlier after ambulatory surgery. Outpatients are normally transferred from the OR to the PACU, followed by transfer to the Phase II step-down (day-surgery unit) before discharge home. With conventional fast-tracking, it is possible to bypass the PACU and take patients directly from the OR to the step-down unit if they meet specific criteria before leaving the OR. Alternatively, if the step-down unit is already functioning at maximum capacity, the PACU can be restructured to include a fast-track area, where appropriate patients are treated as if they had been admitted directly to the step-down unit. For these PACU fast-track patients, less monitoring is performed, a family member is permitted to be with the patient, and the patient is allowed to ambulate, change into street clothes, and be discharged home directly from the PACU without any time restrictions. Preliminary studies have shown that outpatients who are fast-tracked can be discharged home earlier without any increase in complications or side effects. Importantly, fast-tracking after ambulatory surgery does not seem to compromise patient satisfaction with the surgical experience.

Inhalation versus total intravenous anesthesia for lumbar disc herniation: comparison of hemodynamic effects, recovery characteristics, and cost

The clinical effects, recovery characteristics, and costs of total intravenous anesthesia (TIVA), sevoflurane, and isoflurane anesthesia have been measured in various out-patient operations, but have not been evaluated in patients undergoing laminectomy or discectomy. In the current study, the authors assessed the hemodynamic characteristics, recovery, and cost analyzes after laminectomy and discectomy operations, comparing TIVA, sevoflurane, and isoflurane anesthesia. Sixty American Society of Anesthesiologists I and II patients were randomly divided into three groups, each consisting of 20 patients. Group I received propofol-alfentanil, Group 2 received sevoflurane-N2O, and Group 3 received isoflurane-N2O. At the end of surgery, the anesthetics were discontinued, and recovery from anesthesia was assessed by measuring the time until spontaneous eye opening and the time until response to verbal commands. The drug and delivery costs were calculated in United States dollars. No significant differences were found in the demographic data. Heart rate and mean arterial pressure decreased significantly after induction of anesthesia in the TIVA group, compared to the two other groups ( P < .05 for both comparisons). The fastest recovery was seen in the TIVA group. Incidences of postoperative nausea, vomiting, and pain were significantly reduced after TIVA ( P < .05 for both comparisons). Thus, TIVA patients required fewer additional drugs and showed the lowest additional costs in the post-anesthesia care unit. However, the total cost was significantly higher in the TIVA group than in the sevoflurane and isoflurane groups (52.73 dollars, 29.99 dollars, and 24.14 dollars, respectively) ( P < .05). Total intravenous anesthesia was associated with the highest intraoperative cost but provided the most rapid recovery from anesthesia, and the least frequent postoperative side effects.

Fast-tracking after outpatient laparoscopy: reasons for failure after propofol, sevoflurane, and desflurane anesthesia

IMPLICATIONS

In this study, although 41%-94% of the patients were fast-track eligible after laparoscopic surgery, only 35%-53% of the patients actually bypassed the postanesthesia care unit (PACU) because of anesthetic-related factors and surgical complications. Residual sedation was the most common anesthetic-related cause of failure to bypass thePACU.

The use of an anesthesia information management system for prediction of antiemetic rescue treatment at the postanesthesia care unit

We used an anesthesia information management system (AIMS) to devise a score for predicting antiemetic rescue treatment as an indicator for postoperative nausea and vomiting (PONV) in the postanesthesia care unit (PACU). Furthermore, we wanted to investigate whether data collected with an AIMS are suitable for comparable clinical investigations. Over a 3-yr period (January 1, 1997, to December 31, 1999), data sets of 27,626 patients who were admitted postoperatively to the PACU were recorded online by using the automated anesthesia record keeping system NarkoData(R) (IMESO GmbH, Hüttenberg, Germany). Ten patient-related, 5 operative, 15 anesthesia-related, and 4 postoperative variables were studied by using forward stepwise logistic regression. Not only can the probability of having PONV in the PACU be estimated from the 3 previously described patient-related (female gender, odds ratio [OR] = 2.45; smoker, OR = 0.53; and age, OR = 0.995) and one operative variables (duration of surgery, OR = 1.005), but 3 anesthesia-related variables (intraoperative use of opioids, OR = 4.18; use of N(2)O, OR = 2.24; and IV anesthesia with propofol, OR = 0.40) are predictive. In implementing an equation for risk calculation into the AIMS, the individual risk of PONV can be calculated automatically.

IMPLICATIONS

The aim of this study was to investigate predictors for postoperative nausea and vomiting by using online anesthesia records. With the help of computerized data evaluation, 7 of 34 variables could be detected as risk factors. By implementing an automatic score into the record keeping system, an individual risk calculation could be made possible.

Postoperative nausea and vomiting after sevoflurane with or without ondansetron compared with propofol in female patients undergoing breast surgery

IMPLICATIONS

We studied 180 female patients undergoing breast surgery. The patients were randomly allocated to receive one of three anesthetic techniques. Compared with either propofol or sevoflurane alone, sevoflurane with ondansetron resulted in a decreased incidence of postoperative nausea and vomiting. Sevoflurane with ondansetron prophylaxis is a good alternative to propofol with respect to avoiding postoperative nausea and vomiting.