The optimal dose of remifentanil for acceptable intubating conditions during propofol induction without neuromuscular blockade

Determining the optimum dose of remifentanil in combination with propofol for total intravenous anaesthesia in hysteroscopy under Narcotrend and SPI monitoring

Background

Outpatient hysteroscopic surgery requires patients to be anaesthetised and recover quickly, and the drugs used must be safe and effective. Remifentanil is typically co-administered with propofol as total intravenous anaesthesia (TIVA) for hysteroscopy because of its favourable pharmacokinetic and pharmacodynamic properties. However, the optimal dose of remifentanil when co-administered with propofol without neuromuscular blocking agents (NMBAs) has not been established.

Objectives

In this sequential dose-finding study, the 90% effective dose (ED90) of remifentanil effect-site concentration (Ce) combined with propofol without NMBAs during outpatient hysteroscopy was calculated to minimise the side effects of using higher doses.

Design

This sequential dose-finding study was conducted in August 2022.

Methods

Forty patients who underwent outpatient hysteroscopy under TIVA were included in the study. With a biased coin up-and-down design, the initial remifentanil Ce was established at 2 ng/mL, and the subsequent remifentanil dosage was determined based on the reaction of the previous patient. The primary outcome was a remifentanil Ce that resulted in successful TIVA by maintaining a Narcotrend index < 60, surgical pleth index (SPI) < 50, and without patient movement throughout hysteroscopy. Secondary outcomes included rates of hypotension-related symptoms and interventions, drug consumption, post-anaesthesia care unit (PACU)-estimated visual analogue scale (VAS) and Ramsay sedation scores, modified Aldrete scores, and other adverse effects of anaesthesia. The ED90 and 95% confidence intervals (CI) were estimated using isotonic regression methods and bootstrapping.

Results

For TIVA without NMBAs during outpatient hysteroscopy, the ED90 Ce of remifentanil combined with propofol was determined to be 2.75 ng/mL (95% CI, 2.50-3.00 ng/mL). The incidence of peri-operative adverse effects of anaesthesia was relatively low. All the patients had satisfactory VAS, Ramsay sedation, and modified Aldrete scores in the PACU.

Conclusion

Remifentanil at a Ce of 2.75 ng/mL is recommended for TIVA combined with propofol in outpatient hysteroscopic surgery.

Trial registration

http://www.chictr.org.cn (ChiCTR2200062284; 31/7/2022).

Assessment of remifentanil for rapid sequence induction and intubation in patients at risk of pulmonary aspiration of gastric contents compared to rapid-onset paralytic agents: study protocol for a non-inferiority simple blind randomized controlled trial (the REMICRUSH study)

Background

Rapid-onset paralytic agents are recommended to achieve muscle relaxation and facilitate tracheal intubation during rapid sequence induction in patients at risk of pulmonary aspiration of gastric contents. However, opioids are frequently used in this setting. The study’s objective is to demonstrate the non-inferiority of remifentanil compared to rapid-onset paralytic agents, in association with an hypnotic drug, for tracheal intubation in patients undergoing  procedure under general anesthesia and at risk of pulmonary aspiration of gastric contents.

Methods

The REMICRUSH (Remifentanil for Rapid Sequence Induction of Anaesthesia) study is a multicenter, single-blinded, non-inferiority randomized controlled trial comparing remifentanil (3 to 4 μg/kg) with rapid-onset paralytic agents (succinylcholine or rocuronium 1 mg/kg) for rapid sequence induction in 1150 adult surgical patients requiring tracheal intubation during general anesthesia. Enrolment started in October 2019 in 15 French anesthesia units. The expected date of the final follow-up is October 2021. The primary outcome is the proportion of successful tracheal intubation without major complications. A non-inferiority margin of 7% was chosen. Analyses of the intent-to-treat and per-protocol populations are planned.

Discussion

The REMICRUSH trial protocol has been approved by the ethics committee of The Comité de Protection des Personnes Sud-Ouest et Outre-Mer II and will be carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. The results of this study will be disseminated through presentations at scientific conferences and publications in peer-reviewed journals. The REMICRUSH trial is the first randomized controlled trial powered to investigate whether remifentanil with hypnotics is non-inferior to rapid-onset paralytic agents with hypnotic in rapid sequence induction of anesthesia for full stomach patients considering successful tracheal intubation without major complication.

Trial registration

ClinicalTrials.gov NCT03960801. Registered on May 23, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05192-x.

Intubation and Ventilation amid the COVID-19 Outbreak: Wuhan's Experience

The COVID-19 outbreak has led to 80,409 diagnosed cases and 3,012 deaths in mainland China based on the data released on March 4, 2020. Approximately 3.2% of patients with COVID-19 required intubation and invasive ventilation at some point in the disease course. Providing best practices regarding intubation and ventilation for an overwhelming number of patients with COVID-19 amid an enhanced risk of cross-infection is a daunting undertaking. The authors presented the experience of caring for the critically ill patients with COVID-19 in Wuhan. It is extremely important to follow strict self-protection precautions. Timely, but not premature, intubation is crucial to counter a progressively enlarging oxygen debt despite high-flow oxygen therapy and bilevel positive airway pressure ventilation. Thorough preparation, satisfactory preoxygenation, modified rapid sequence induction, and rapid intubation using a video laryngoscope are widely used intubation strategies in Wuhan. Lung-protective ventilation, prone position ventilation, and adequate sedation and analgesia are essential components of ventilation management.

Comparison of intubating conditions after induction with propofol and remifentanil or sufentanil : Randomized controlled REMIDENT trial for surgical tooth extraction

PURPOSE

The aim of this study was to compare tracheal intubation conditions after induction of anesthesia with a bolus of propofol-sufentanil or propofol-remifentanil and a rapid induction technique.

MATERIAL AND METHODS

A total of 70 patients (American Society of Anesthesiologists (ASA) classification I‑II) undergoing outpatient surgery under general anesthesia with intubation for tooth extraction were randomly assigned to two groups in this double-blind study. Patients received either a bolus of remifentanil (3 μg/kg) or sufentanil (0.3 μg/kg) together with 2.5 mg/kg propofol for intubation. The primary outcome was the percentage of excellent intubation conditions and the secondary outcomes were the percentage of patients with a decrease of over 20% in mean arterial pressure (MAP) or heart rate (HR), time to achieve spontaneous respiration, time between the end of surgery and extubation and time to achieve an Aldrete score of 10. VAS pain score was >3 or having laryngeal pain 15 min after arriving in the postanesthesia care unit (PACU) were also analyzed.

RESULTS

Intubating conditions (perfect + good conditions) were significantly better with remifentanil than with sufentanil (88.5% vs. 68.6%; p = 0.01). When using remifentanil, the hemodynamic conditions were good. Using remifentanil did not significantly increase the pain score or the laryngeal pain in the recovery room. This was confirmed by no significant differences between the groups for morphine consumption. Remifentanil significantly decreased the time to achieve an Aldrete score of 10.

CONCLUSION

When intubation without muscle relaxants is required, intubating conditions are much better when a remifentanil bolus is used compared to a sufentanil bolus. The remifentanil/propofol rapid induction technique is a valuable technique to quickly intubate and achieve good conditions.

High-flow Nasal Cannulae Versus Non-invasive Ventilation for Preoxygenation of Obese Patients: The PREOPTIPOP Randomized Trial

BACKGROUND

In obese patients, preoxygenation with non-invasive ventilation (NIV) was reported to improve outcomes compared with facemask. In this setting, high-flow nasal cannulae (HFNC) used before and during intubation has never been studied against NIV.

METHODS

The PREOPTIPOP study is a randomised, single-centre, open-labelled, controlled trial including obese patients requiring intubation before scheduled surgery. Patients were randomised to receive preoxygenation by HFNC or NIV. HFNC was maintained throughout intubation whereas NIV was removed when apnea occurred to perform laryngoscopy. The study was designed to assess the superiority of HNFC. The primary outcome was the lowest level of end-tidal oxygen concentration (EtO2) within 2 min after intubation. Secondary outcomes included drop in pulse oximetry and complications related to intubation.

MAIN FINDINGS

A total of 100 patients were randomised. The intent-to-treat analysis found median [IQR] lowest EtO2 of 76% [66-82] for HFNC and 88% [82-90] for NIV (mean difference - 12·1 [- 15·1 to - 8·5], p < 0·0001). Mild desaturation below 95% was more frequent with HFNC (30%) than with NIV (12%) (relative risk 2·5, IC 95% [1·1 to 5·9], p = 0·03) and median lowest SpO2 during intubation was 98% [93-99] in HFNC vs. 99% [97-100] in NIV (p = 0·03). Severe and moderate complications were not different but patients reported more discomfort with NIV (28%) vs. HFNC (4%), p = 0·001.

INTERPRETATION

Compared with NIV, preoxygenation with HFNC in obese patients provided lower EtO2 after intubation and a higher rate of desaturation < 95%.

FUNDING

Institutional funding, additional grant from Fisher & Paykel.

TRIAL REGISTRATION

Clinical trial Submission: April 10, 2017. Registry name: Preoxygenation Optimization in Obese Patients: High-flow Nasal Cannulae Oxygen Versus Non-invasive Ventilation: A Single-centre Randomised Controlled Study. The PREOPTIPOP Study. Clinicaltrials.gov identifier: NCT03106441 N°ID RCB: 2017-A00305-48. Institutional review Board: CPP Nord-Ouest I, registration number 019/2017. URL registry:https://clinicaltrials.gov/ct2/show/NCT03106441.

Pharmacologic Considerations of Anesthetic Agents in Pediatric Patients: A Comprehensive Review

Acute pain in the pediatric population has important differences in terms of biology, intrapopulation variation, and epidemiology. Discussion as to the pharmacologic considerations of anesthetic agents, such as induction agents, neuromuscular blockers, opioids, local anesthetics, and adjuvant agents, is presented in this article. Special considerations and concerns, such as risk for propofol infusion syndrome and adverse potential side effects of anesthesia agents, are discussed. Anesthesiologists managing pediatric patients need to have a firm understanding of physiologic and pharmacologic differences compared with the adult population. Future studies to improve the understanding of pharmacokinetics in the pediatric population are needed.

Sugammadex ED90 dose to reverse the rocuronium neuromuscular blockade in obese patients

Objective

to determine the ED90 (minimum effective dose in 90% of patients) of sugammadex for the reversal of rocuronium-induced moderate neuromuscular blockade (NMB) in patients with grade III obesity undergoing bariatric surgery.

Methods

we conducted a prospective study with the biased coin up-and-down sequential design. We chosen the following doses: 2.0mg/Kg, 2.2mg/Kg, 2.4mg/Kg, 2.6mg/Kg, 2.8mg/Kg. The complete reversal of rocuronium-induced NMB considered a T4/T1 ratio ≥0.9 as measured by TOF. After induction of general anesthesia and calibration of the peripheral nerve stimulator and accelerometer, we injected rocuronium 0.6mg/kg. We administered propofol and remifentanil by continuous infusion, and intermittent boluses of rocuronium throughout the procedure.

Results

we evaluated 31 patients, of whom 26 had displayed successful reversal of the NMB with sugammadex, and failure in five. The mean time to complete moderate NMB reversal was 213 seconds (172-300, median 25-75%). The ED90 of sugammadex calculated by regression was 2.39mg/kg, with a 95% confidence interval of 2.27-2.46 mg/kg.

Conclusion

the ED90 of sugammadex in patients with grade III obesity or higher was 2.39mg/kg.

Prophylactic effect of ephedrine to reduce hemodynamic changes associated with anesthesia induction with propofol and remifentanil

BACKGROUND

One of the complications of anesthesia induction with propofol is a substantial decrease in arterial blood pressure and heart rate (HR), which can be intensified by adding remifentanil. This study aimed to assess the prophylactic effects of two doses of ephedrine to control the hypotension and bradycardia caused by anesthesia induced with propofol and remifentanil.

MATERIALS AND METHODS

A total of 150 patients candidate for short-term minor elective orthopedic and ophthalmic surgery under general anesthesia were randomized to three groups receiving normal saline, low dose ephedrine (0.07 mg/kg) or high dose ephedrine (0.15 mg/kg). Anesthesia was induced in all groups with propofol 2.5 mg/kg and remifentanil 3 μg/kg. No neuromuscular blocking agent was used. Patients' hemodynamic status was assessed in the following four steps: Immediately before, 2 min after induction of anesthesia, as well as 1 and 5 min after intubation.

RESULTS

A total of 143 patients consisting of 46 patients in the low dose ephedrine (0.07 mg/kg) group, 49 patients in the high dose ephedrine (0.15 mg/kg) group and 48 controls completed the trial. In all three groups, after induction of anesthesia, significant decreases occurred in the mean systolic, diastolic and mean arterial pressures, as well as in the mean HR. This decline was highest in the control group and lowest in the high dose ephedrine (0.15 mg/kg) group.

CONCLUSION

Our findings suggest that the administration of high dose ephedrine (0.15 mg/kg) may have a significant effect in preventing hypotension and bradycardia after anesthesia induction with propofol and remifentanil.

Pediatric ambulatory anesthesia

Pediatric patients often undergo anesthesia for ambulatory procedures. This article discusses several common preoperative dilemmas, including whether to postpone anesthesia when a child has an upper respiratory infection, whether to test young women for pregnancy, which children require overnight admission for apnea monitoring, and the effectiveness of nonpharmacological techniques for reducing anxiety. Medication issues covered include the risks of anesthetic agents in children with undiagnosed weakness, the use of remifentanil for tracheal intubation, and perioperative dosing of rectal acetaminophen. The relative merits of caudal and dorsal penile nerve block for pain after circumcision are also discussed.

Management of the anticipated and unanticipated difficult airway in anesthesia outside the operating room

PURPOSE OF REVIEW

The number of diagnostic and interventional procedures outside the operating room has dramatically increased over the last years. However, providing well tolerated anesthesia with the same standard of care in these locations is often challenging to the anesthesiologist. The remote locations include different organizational aspects and hazards. Airway management in general is still confronted with scenarios of difficult intubation and ventilation and often leads to significant morbidity and mortality. Continuous awareness of the potential complications is urged when providing anesthesia for remote procedures.

RECENT FINDINGS

Recent studies have poorly addressed the issue of airway management by trained anesthesiologists outside the operating room. The majority of evidence is provided in the field of emergency medicine and intensive care settings. However, when dealing with difficult airway management in the remote setting, careful assessment and preparation is even more important than in the operating room. New evidence concerning prediction of ventilation and intubation must be incorporated in algorithms of airway management. Different anesthetic regimens using remifentanil and avoiding the use of neuromuscular blockers have to be carefully considered since they might change the scenario of intubation conditions. The new era of video laryngoscopes offers important potential to increase the tools for airway management. These new devices have the perfect design to be incorporated in remote settings. However, studies mainly focus on the emergency department and ICU. Also, there is currently a lack of consensus among professionals about their use and the large number of different devices seems to avoid careful comparisons.

SUMMARY

Airway management outside the operating room is challenging and needs the implementation of algorithms including the new airway devices. The recent update of the practice guidelines about difficult airway management of the American Society of Anesthesiologists remains the standard reference guide.

Tracheal intubation in intellectually disabled patients: clinical usefulness of remifentanil and sevoflurane without a muscle relaxant

OBJECTIVE

To compare two remifentanil doses (1 µg/kg and 2 µg/kg) in order to determine the preferred dose in intellectually disabled patients undergoing day care dental surgery under sevoflurane-induced general anaesthesia.

METHODS

Patients were randomly assigned to receive either 1 µg/kg (group 1) or 2 µg/kg (group 2) remifentanil; both groups received 8% sevoflurane anaesthesia induction. All other conditions were identical in both groups. Heart rate (HR), mean arterial pressure (MAP) and intubation conditions were assessed.

RESULTS

A total of 27/30 (90.0%) patients in group 1 and 29/30 patients (96.7%) in group 2 had acceptable intubation conditions. Remifentanil administration resulted in significant reductions in HR compared with baseline levels, in both groups. There were no significant between-group differences in HR at any timepoint. MAP decreased significantly compared with baseline in group 2 only.

CONCLUSION

Successful tracheal intubation in intellectually disabled patients can be accomplished with a combination of 1 µg/kg or 2 µg/kg remifentanil and 8% sevoflurane anaesthesia induction, without the requirement for neuromuscular blocking drugs.

Cardiac considerations in the operative management of the patient with Duchenne or Becker muscular dystrophy

Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD) is a progressive multisystem neuromuscular disorder. In addition to the skeletal muscle, the myocardium in the DMD/BMD patient is dystrophin deficient which results in a progressive cardiomyopathy. The myopathic myocardium poses significant risk of increased morbidity and mortality at the time of major surgical procedures. Careful attention must be given to the DMD/BMD patient during the intraoperative and postoperative period. Anesthesia selection is critical and anesthetics should be avoided which have been shown to be harmful in this patient population. Preanesthesia assessment should include cardiac consultation and detailed preoperative evaluation. Intraoperative management needs to insure that the weakened myocardium is not compromised by physiologic changes such as hypotension or major fluid shifts. Finally, attention to the cardiac status of the patient must continue into the postoperative period. The surgical care of the DMD/BMD patient requires a multispecialty approach to insure operative success.