Determining the Target Concentration of Propofol for Sedation in Patients Undergoing Endoscopic Retrograde Cholangiopancreatography: A Target-Controlled Infusion Approach

Introduction Endoscopic retrograde cholangiopancreatography (ERCP) is vital for diagnosing and treating biliary and pancreatic diseases, necessitating deep sedation typically achieved through total intravenous anesthesia. Propofol, with its favorable pharmacokinetic profile, is the preferred sedative, but conventional administration methods of mg/kg boluses or infusion rates pose challenges. Target-controlled infusion (TCI) systems offer a solution that ensures precise dose delivery of propofol. Despite its widespread use, the literature lacks specific guidance on the target plasma concentration (Cp) of propofol for sedation in patients undergoing ERCP. Methods A prospective interventional study was conducted at the Institute of Liver and Biliary Sciences, Delhi, India to determine the target Cp of propofol for sedation during ERCP. The study enrolled 86 American Society of Anesthesiologists (ASA) grade I and II patients aged 18-70 years. The primary objective was to establish the optimal propofol concentration for sedation as guided by a bispectral index (BIS) value of 60-70. Secondary outcomes included induction time, recovery time, total propofol consumption, and the occurrence of adverse events (if any). The Marsh pharmacokinetic model guided the TCI pump, adjusting Cp until the target sedation was achieved. Results The mean Cp of propofol to maintain the BIS value 60-70 was 2.21 ± 0.42 µg/ml. Age-wise analysis revealed variations, emphasizing the need for individualized dosing. Induction time was 4.21 ± 0.68 minutes; recovery times were seven minutes (median, IQR: 5-10 minutes) for BIS >80 and seven minutes (median, IQR: 5-10 minutes) for achieving a Modified Observer's Assessment of Alertness/Sedation score of ≥5. The mean propofol consumption was 6.24 mg/kg/hr. Side effects were minimal, with 1.16% experiencing transient hypoxia and hypotension. Conclusion The study establishes a mean target propofol concentration of 2.21 ± 0.42 µg/ml for sedation in ASA I and II patients undergoing ERCP.

Safety and efficacy of target-controlled infusion versus intermittent bolus administration of propofol for sedation in colonoscopy: a randomized controlled trial

BACKGROUND

Our objective was to compare the safety and efficacy of Target-Controlled Infusion (TCI) versus intermittent bolus of propofol for colonoscopy sedation.

METHODS

We conducted a randomized (1:1), single-blind, parallel-group superiority trial with fifty ASA I or II patients, both sexes, aged 18 to 65 years, Body Mass Index ≤ 30 kg.m-2, undergoing colonoscopy, allocated to receive propofol by TCI (effect-site, 2 μg.mL-1 plus 0.5 μg.mL-1 until unconsciousness and as necessary for agitation) or intermittent bolus (1 mg.kg-1 plus 0.5 mg.kg-1 every 5 minutes or as above). The primary safety outcome was the need for airway maneuvers and the primary efficacy outcome was the need for interventions to adjust the level of sedation. Secondary outcomes included incidence of agitation, propofol dose, and time to recovery.

RESULTS

The median (IQR) number of airway maneuvers and interventions needed to adjust sedation was 0 (0‒0) vs. 0 (0‒0) (p = 0.239) and 1 (0‒1) vs. 3 (1‒4) (p < 0.001) in the TCI and control groups, respectively. Agitation was more common in the intermittent bolus group ‒ 2 (0‒2) vs. 1 (0‒1), p < 0.001. The mean ± SD time to recovery was 4.9 ± 1.4 minutes in the TCI group vs. 2.3 ± 1.6 minutes in the control group (p < 0.001). The total propofol dose was higher in the TCI group (234 ± 46 µg.kg-1.min-1 vs. 195 ± 44 µg.kg-1.min-1 (p = 0.040)).

CONCLUSIONS

During colonoscopy, TCI is as safe as intermittent bolus of propofol while reducing the incidence of agitation and the need for dose adjustments. However, intermittent bolus administration was associated with lower total propofol dose and earlier recovery.

Safety and efficacy of target controlled infusion administration of propofol and remifentanil for moderate sedation in non-hospital dental practice

Background

Fearful and anxious patients who find dental treatment intolerable without sedative and analgesic support may benefit from moderate sedation. Target controlled infusion (TCI) pumps are superior to bolus injection in maintaining low plasma and effect-site concentration variability, resulting in stable, steady-state drug concentrations. We evaluated the safety and efficacy of moderate sedation with remifentanil and propofol using TCI pumps in non-hospital dental settings.

Methods

A prospective chart review was conducted on 101 patients sedated with propofol and remifentanil using TCI pumps. The charts were completed at two oral surgeons and one general dentist's office over 6 months. Hypoxia, hypotension, bradycardia, and over-sedation were considered adverse events and were collected using Tracking and Reporting Outcomes of Procedural Sedation (TROOPS). Furthermore, patient recovery time, sedation length, drug dose, and patient satisfaction questionnaires were used to measure sedation effectiveness.

Results

Of the 101 reviewed sedation charts, 54 were of men, and 47 were of women. The mean age of the patients was 40.5 ±18.7 years, and their mean BMI was 25.6 ± 4.4. The patients did not experience hypoxia, bradycardia, and hypotension during the 4694 min of sedation. The average minimum Mean Arterial Pressure (MAP) and heartbeats were 75.1 mmHg and 60.4 bpm, respectively. 98% of patients agreed that the sedation technique met their needs in reducing their anxiety, and 99% agreed that they were satisfied with the sedation 24 hours later. The average sedation time was 46.9 ± 55.6 min, and the average recovery time was 12.4 ± 4.4 min. Remifentanil and propofol had mean initial effect-site concentration doses of 0.96 µ/ml and 1.0 ng/ml respectively. The overall total amount of drug administered was significantly higher in longer sedation procedures compared to shorter ones, while the infusion rate decreased as the procedural stimulus decreased.

Conclusion

According to the results of this study, no patients experienced adverse events during sedation, and all patients were kept at a moderate sedation level for a wide range of sedation times and differing procedures. The results showed that TCI pumps are safe and effective for administering propofol and remifentanil for moderate sedation in dentistry.

Comparison of Single Target-Controlled Infusion Pump-Delivered Mixed Propofol and Remifentanil with Two Target-Controlled Infusion Pumps-Delivered Propofol and Remifentanil in Patients Undergoing Breast Cancer Surgery-A Prospective Study

Total intravenous anesthesia (TIVA) with remifentanil and propofol (RP) is considered to be an ideal type of general anesthesia (GA) for pediatric and adult patients undergoing medical procedures. However, delivery of an RP mixture by target-controlled infusion (TCI) for GA in surgical procedures has not been described. We investigated the merit of this approach for breast cancer surgery. Eighty-four patients (n = 42 per group) were randomly allocated to propofol and remifentanil either delivered by separate TCI pumps (S group) or in an RP mixture by a single TCI pump (M group). Dosages were adjusted based on the bispectral index (BIS) and the analgesia nociception index (ANI). The primary outcomes were adequate anesthesia (BIS 40-60 and ANI 50-70, respectively), acceptable hemodynamic fluctuations (<30% of baseline) with less frequent TCI pump adjustments, bolus injections of anesthetics, and total consumption of anesthetics during the procedure. The secondary endpoints included time of emergence from anesthesia, patient satisfaction, postoperative pain, rescue with opioids, and adverse events. The characteristics of patients, hemodynamic parameters, BIS and ANI scores, duration of surgery, anesthesia, and emergence were not significantly different between groups. The adjustment frequency of TCI was significantly higher in the S group (3 (range 0-6) vs. 2 (0-6) times; p = 0.005). The total dosage of anesthetics, pain rating, patient satisfaction, need for opioids postoperatively, and incidence of adverse events were not significantly different. We have demonstrated that this RP mixture provided adequate hypnotic and analgesic effects under BIS and ANI monitoring in patients undergoing breast cancer surgery within 1 h.

Use of ketamine and xylazine anesthesia in dogs: A retrospective cohort study of 3,413 cases

The information regarding the risk of anesthesia-related death in veterinary medicine is scarce, and little is known about the mortality risk of specific anesthetics. The study conducted during 2019 at University of Sarajevo, Veterinary faculty, aimed to estimate the mortality risk of intermittent injectable ketamine-xylazine anesthesia in dogs and to investigate the potential relationship between mortality rate and anesthesiologists’ experience. Anesthetic records, where ketamine and xylazine combination was used for anesthesia induction and maintenance, were reviewed and divided into two groups: inexperienced (AN1) and experienced anesthesiologists (AN2). Inexperienced anesthesiologists were constantly supervised by experienced ones, whose corrective interventions were recorded. Overall detected mortality rate was 0.15%, with 0.18% and 0.11% in the AN1 and AN2 groups, respectively. A statistically significant difference was not found. Records of the AN1 group revealed interventions of experienced anesthesiologist in 92% of cases. Detected mortality rate was within the values previously established for inhalant anesthesia indicating high safety in usage of investigated protocol, if performed by experienced anesthesiologists. The high percentage of interventions of a senior anesthesiologist suggests that supervised upskilling of inexperienced anesthesiologists before their independent work could result in a better outcome.

Comparison of 2 effect-site concentrations of remifentanil with midazolam during transrectal ultrasound-guided prostate biopsy under procedural analgesia and sedation: A randomized controlled study

BACKGROUND

Until now, target-controlled infusion of remifentanil with midazolam for transrectal ultrasound-guided prostate biopsy has not been described. Here, we investigate 2 effect-site concentrations of remifentanil with intermittent bolus midazolam for transrectal ultrasound-guided prostate biopsy under procedural analgesia and sedation.

METHODS

A prospective, randomized controlled trial including patients who received a transrectal ultrasound-guided prostate biopsy between February 2019 and January 2021 was conducted. Group 1 and Group 2 were respectively administered an initial effect-site concentration of remifentanil of 1.0 ng/mL and 2.0 ng/mL by a target-controlled infusion pump with Minto model. In both groups, maintenance of the effect-site concentration of remifentanil was adjusted upward and downward by 0.5 ng/mL to keep patient comfort with acceptable pain (remaining moveless), and mean arterial pressure and heart rate within baseline levels ± 30%, and using intermittent bolus midazolam to keep the Observer's Assessment of Alertness/Sedation scale between 2 and 4. The primary outcome was to determine which effect-site concentration of remifentanil provide adequate patient comfort with acceptable pain (remaining moveless) during the procedure.

RESULTS

A total of 40 patients in Group 1 and 40 patients in Group 2 were eligible for analysis. Most parameters were insignificantly different between Group 1 and Group 2, except Group 1 having higher peripheral oxygen saturation while probe insertion compared with Group 2. Group 2 patients had less intraoperative movements affecting the procedure (2 vs 18; P < .001), and less total times of target-controlled infusion pump adjustment (0 [0-1] vs 1 [0-3], P < .001) compared with group 1. However, group 1 patients had less apnea with desaturation (peripheral oxygen saturation < 90%; 0 vs 9, P = .002) and less remifentanil consumption (94.9 ± 25.5 μg vs 106.2 ± 21.2 μg, P = .034) compared to Group 2.

CONCLUSION

In transrectal ultrasound-guided prostate biopsy, target-controlled infusion with remifentanil Minto model target 2.0 ng/mL with 3 to 4 mg midazolam use provided sufficient analgesia and sedation, and appropriate hemodynamic and respiratory conditions.

Pharmacokinetic Study of Vadadustat and High-Resolution Mass Spectrometric Characterization of its Novel Metabolites in Equines for the Purpose of Doping Control

BACKGROUND

Vadadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, is a substance which carries a lifetime ban in both horse racing and equestrian competition. A comprehensive metabolic study of vadadustat in horses has not been previously reported.

OBJECTIVE

Metabolism and elimination profiles of vadadustat in equine plasma and urine were studied for the purpose of doping control.

METHODS

A nasoesophageal administration of vadadustat (3 g/day for 3 days) was conducted on three thoroughbred mares. Potential metabolites were comprehensively detected by differential analysis of full-scan mass spectral data obtained from both in vitro studies with liver homogenates and post-administration samples using liquid chromatography high-resolution mass spectrometry. The identities of metabolites were further substantiated by product ion scans. Quantification methods were developed and validated for the establishment of the excretion profiles of the total vadadustat (free and conjugates) in plasma and urine.

RESULTS

A total of 23 in vivo and 14 in vitro metabolites (12 in common) were identified after comprehensive analysis. We found that vadadustat was mainly excreted into urine as the parent drug together with some minor conjugated metabolites. The elimination profiles of total vadadustat in post-administration plasma and urine were successfully established by using quantification methods equipped with alkaline hydrolysis for cleavage of conjugates such as methylated vadadustat, vadadustat glucuronide, and vadadustat glucoside.

CONCLUSION

Based on our study, for effective control of the misuse or abuse of vadadustat in horses, total vadadustat could successfully be detected for up to two weeks after administration in plasma and urine.

Perioperative Considerations for Person-Centered Gender-Affirming Surgery

With more than 1 million people identifying as transgender in the United States alone, the likelihood of encountering a transgender patient and their family of choice in the perioperative setting is very high. A lack of data exists to equitably inform transgender-specific issues, as well as the associated morbidity during the transgender reassignment perioperative period. Anaesthesiologists should actively acquire the knowledge and skills needed to inclusively and respectfully manage these patients and be aware of their unique physiological and psychosocial needs. The pre-operative approach includes a detailed history, focusing on the patients cross-sex hormone treatment (CSHT) regimen and associated medical conditions. An in-depth understanding of commonly used hormones such as estrogen and testosterone and their effect in the perioperative periods is essential. The physical examination should be relevant to the anatomy that is currently present while taking into consideration feminising and masculinising procedures (e.g., genioplasty, thyroid cartilage augmentation), how these interventions alter the anatomy, and potential airway complications. Laboratory results should be interpreted with care – and with expert assistance if needed - as hormone therapy might affect reference values. In addition, risk assessment tools should be used with caution since they often include sex in their scoring system but do not account for the use of CSHT. Intraoperative considerations include urethral catheter placement, drug dosing, and drug interactions that are commonly encountered in the transgender patient. Special attention should be taken in transgender females who have undergone vocal feminization, as case reports have described unexpected difficult airway management. A multimodal approach, which includes regional blocks and attention to pre-existing chronic pain conditions, should be employed as part of the post-operative pain management plan. The post-operative nausea and vomiting risk has not yet been established in this population, requiring appropriate anti-emetic prophylaxis. Despite societal advances that improve transgender health, the medical community still lacks empirical evidence to effectively mitigate the distinctive challenges confronted by this at-risk population.

Total Intravenous Anesthesia in a Malignant Hyperthermia-Susceptible Patient with Klinefelter Syndrome Undergoing Orthognathic Surgery

ABSTRACT

A patient with Klinefelter syndrome and skeletal Class III malocclusion experienced a malignant hyperthermia-like reaction while undergoing orthognathic surgery. The patient fully recovered after prompt diagnosis and management, and surgery was reattempted under total intravenous anesthesia. The patient was discharged without any anesthetic complications and was satisfied with the surgical results. This is the first described case of a malignant hyperthermia-like event in a patient with Klinefelter syndrome. Total intravenous anesthesia may be safely administered in malignant hyperthermia-susceptible patients who require orthognathic surgery.

Comparison of 2 effect-site concentrations of remifentanil with midazolam during percutaneous transluminal balloon angioplasty under monitored anesthesia care: A randomized controlled study

BACKGROUND

Until now, target-controlled infusion of remifentanil with midazolam in percutaneous transluminal balloon angioplasty for dysfunctional hemodialysis fistulas has not been described. Here, we investigate 2 effect-site concentrations of remifentanil with intermittent bolus midazolam for percutaneous transluminal balloon angioplasty under monitored anesthesia care.

METHODS

A prospective, randomized controlled trial including patients who received a percutaneous transluminal balloon angioplasty between March 2019 and March 2021 was conducted. Group 1 and Group 2 were, respectively, administered an initial effect-site concentration of remifentanil of 1.0 and 2.0 ng/mL by a target-controlled infusion pump with Minto model. In both groups, maintenance of the effect-site concentration of remifentanil was adjusted upward and downward by 0.5 ng/mL with intermittent bolus midazolam to keep the Observer's Assessment of Alertness/Sedation scale between 2 and 4, mean arterial pressure and heart rate at baseline levels ± 30%, and patient comfort (remaining moveless). The primary outcome was to determine the appropriate effect-site concentration of remifentanil for the procedure in terms of patient comfort (remaining moveless), hemodynamic conditions, and adverse events. Secondary endpoints included the total dosage of anesthetics and total times of target-controlled infusion pump adjustments.

RESULTS

A total of 40 patients in Group 1 and 40 patients in Group 2 were eligible for analysis. Most parameters were insignificantly different between 2 groups, except Group 1 having higher peripheral oxygen saturation, while local anesthetic injection compared with Group 2. In addition, Group 1 patients had less apnea with desaturation (peripheral oxygen saturation < 90%; 0 vs 6, P = .034), less remifentanil consumption (189.65 ± 69.7 vs 243.8 ± 76.1 μg, P = .001), but more intraoperative movements affecting the procedure (14 vs 4; P = .016), total times of target-controlled infusion pump adjustment [2 (1-4) vs 1 (1-2), P < .001] compared with Group 2.

CONCLUSION

In percutaneous transluminal balloon angioplasty for dysfunctional hemodialysis fistulas, target-controlled infusion with remifentanil Minto model target 2.0 ng/mL with 3 to 4 mg midazolam use provided appropriate hemodynamic conditions, sufficient sedation and analgesia, and acceptable apnea with desaturation.

Effect of target-controlled propofol infusion to reduce the incidence of adverse events for procedural sedation in the emergency department: a systematic review

The administration of propofol target-controlled infusion (TCI) for procedural sedation is standard in a range of hospital settings except for the Emergency Department (ED). Propofol TCI could be an alternative, safer way to provide procedural sedation in the ED compared with other methods of propofol administration. We compare the incidence of adverse events using propofol TCI compared with other methods of propofol administration. We conducted a systematic review of the literature from 1946 to January 2019 identifying studies that compared propofol TCI with other propofol regimens for procedural sedation in the adult population. Studies were assessed for risk of bias using the Cochrane Collaboration risk of bias tool. Seven articles were included. There was significant methodological heterogeneity in all aspects of study designs and definitions of adverse events which precluded a meta-analysis. A systematic review of the studies demonstrated fewer respiratory and cardiovascular adverse outcomes in three of the seven studies. It was not possible to determine if propofol TCI reduces the incidence of adverse events when compared with other sedating regimens using propofol using a descriptive systematic review of the relevant literature. Further research is required to compare the incidence of adverse events using propofol TCI for procedural sedation with other methods of administration in the ED. Future systematic reviews and meta-analysis comparisons would be aided by the use of standard adverse event reporting tools such as that of the Society of Intravenous Anaesthesia.

Anesthetic Management for Awake Tubeless Suspension Microlaryngoscopy

OBJECTIVES/HYPOTHESIS

Patients' eligibility for bilateral selective laryngeal reinnervation surgery is evaluated by suspension microlaryngoscopy (SML) examination with laryngeal electromyography (LEMG). Maintaining spontaneous ventilation, with remifentanil sedation/analgesia without endotracheal tube, to allow the patient to phonate with the surgeon during awake, LEMG is a major challenge for the anesthesiologist and the otorhinololaryngologist. The objective of this study was to evaluate the safety and efficacy of a novel anesthesia protocol to manage airway access during awake tubeless SML.

STUDY DESIGN

Retrospective study.

METHODS

Anesthesia records of patients undergoing awake SML with LEMG were retrospectively analyzed. Procedures were performed with remifentanil sedation/analgesia with targeted controlled infusion (TCI) in combination with local anesthesia. The main outcome was the failure rate of the anesthesia protocol during the procedure. Secondary outcomes were as follows: rate of apnea requiring ventilation, airway bleeding, regurgitation, hemodynamic data as well as vasopressor use, complications, and surgeon satisfaction with the procedure.

RESULTS

Data were obtained for 39 patients between November 2017 and September 2019, the mean age was 52 years and 29 (74%) were female. All procedures were completed without complications (0% [0-9]). Three patients (8% [1.6-20.8]) had an intraoperative episode of hypoxemia requiring mask reventilation. There was no airway bleeding, no regurgitation, and no hypotensive episode. Three patients (8% [1.6-20.8]) had noninvasive ventilation for respiratory distress after the end of the procedure.

CONCLUSIONS

Our results show that awake tubeless SML allowing phonation during LEMG can be realized under sedation and local anesthesia. However, further data are needed concerning the intraoperative and postoperative safety of the procedure.

LEVEL OF EVIDENCE

4. Laryngoscope, 2021.

Smart Portable Pen for Continuous Monitoring of Anaesthetics in Human Serum With Machine Learning

Continuous monitoring of anaesthetics infusion is demanded by anaesthesiologists to help in defining personalized dose, hence reducing risks and side effects. We propose the first piece of technology tailored explicitly to close the loop between anaesthesiologist and patient with continuous drug monitoring. Direct detection of drugs is achieved with electrochemical techniques, and several options are present in literature to measure propofol (widely used anaesthetics). Still, the sensors proposed do not enable in-situ detection, they do not provide this information continuously, and they are based on bulky and costly lab equipment. In this paper, we present a novel smart pen-shaped electronic system for continuous monitoring of propofol in human serum. The system consists of a needle-shaped sensor, a quasi digital front-end, a smart machine learning data processing, in a single wireless battery-operated embedded device featuring Bluetooth Low Energy (BLE) communication. The system has been tested and characterized in real, undiluted human serum, at 37  ^°C. The device features a limit of detection of 3.8  μM, meeting the requirement of the target application, with an electronics system 59% smaller and 81% less power consuming w.r.t. the state-of-the-art, using a smart machine learning classification for data processing, which guarantees up to twenty continuous measure.

Does Hypothermic Circulatory Arrest for Aortic Surgery Trigger Near-Death Experience? Incidence of Near-Death Experiences after Aortic Surgeries Performed under Hypothermic Circulatory Arrest

BACKGROUND

 Understanding near-death experiences (NDE) could provide a new insight into the analysis of human consciousness and the neurocognitive processes happening upon the approach of death. With a temporary interruption of systemic perfusion, aortic surgery under hypothermic circulatory arrest (HCA) may be the only available model of reversible clinical death. We present, herein, the results of an observational study designed to assess the incidence of NDE after aortic surgery.

METHODS

 We performed a prospective study including consecutive patients who underwent thoracic aortic surgery between July 2018 and September 2019 at our institution. Procedures without HCA were included to constitute a control group. The primary outcome was the incidence of NDE assessed with the Greyson NDE scale during the immediate postoperative course, via a standardized interview of the patients in the surgical ward.

RESULTS

 One hundred and one patients were included. Twenty-one patients (20.8%) underwent nonelective interventions for aortic dissection. Ninety-one patients had hemiarch replacement (90.1%). Sixty-seven (66.3%) interventions were performed with HCA, with an average circulatory arrest duration of 26.9 ± 25.5 minutes, and a mean body temperature of 23.7 ± 3.8°C. None of the patients reported any recollection from their period of unconsciousness. There was no NDE experiencer in the study cohort.

CONCLUSION

 Several confounding factors regarding anesthesia, or NDE evaluation, might have impaired the chance of NDE recollections, and might have contributed to this negative result. Whether HCA may trigger NDE remains unknown.

Propofol Target-Controlled Infusion in Emergency Department Sedation (ProTEDS): a multicentre, single-arm feasibility study

BACKGROUND

Procedural sedation is a core skill of the emergency physician. Bolus administration of propofol is widely used in UK EDs. Titrated to an end point of sedation, it has a rapid effect but has been associated with adverse incidents. The use of a target-controlled infusion (TCI) of propofol is not routine but may reduce the incidence of adverse incidents.The primary aims of this single-arm feasibility study were patient satisfaction and to establish recruitment rates for a randomised controlled trial comparing propofol TCI to bolus administration.

METHODS

Four EDs in Scotland, UK, participated. Patients aged 18-65 years, with anterior shoulder dislocation, weight ≥ 50kg, fasted ≥ 90 min were screened. Patients underwent reduction of their dislocated shoulder using TCI propofol. The primary end point was patient satisfaction recorded on a Visual Analogue Scale.

RESULTS

Between 3 April 2017 and 31 December 2018, 25 patients were recruited with a recruitment rate of 20% for the 16-month recruitment window, with a temporary pause to allow amendment of drug dosage.Two patients were excluded. Twenty achieved adequate sedation, defined as a Modified Observer's Assessment of Alertness/Sedation Scale (OAA/S) 3. Successful reduction was achieved in all adequately sedated. Patient satisfaction was documented in 14 patients, mean±SD of 97±9 and time to sedation was 25±8 min. No adverse events were recorded using the Society of Intravenous Anaesthesia adverse event reporting tool.

CONCLUSION

Propofol TCI was acceptable as a method of procedural sedation for patients. The lower than expected recruitment rates highlight the need for dedicated research support.

TRIAL REGISTRATION NUMBER

NCT03442803.

Improved haemodynamic stability and cerebral tissue oxygenation after induction of anaesthesia with sufentanil compared to remifentanil: a randomised controlled trial

BACKGROUND

Balanced anaesthesia with propofol and remifentanil, compared to sufentanil, often decreases mean arterial pressure (MAP), heart rate (HR) and cardiac index (CI), raising concerns on tissue-oxygenation. This distinct haemodynamic suppression might be attenuated by atropine. This double blinded RCT, investigates if induction with propofol-sufentanil results in higher CI and tissue-oxygenation than with propofol-remifentanil and if atropine has more pronounced beneficial effects on CI and tissue-oxygenation in a remifentanil-based anaesthesia.

METHODS

In seventy patients scheduled for coronary bypass grafting (CABG), anaesthesia was induced and maintained with propofol target controlled infusion (TCI) with a target effect-site concentration (Cet) of 2.0 μg ml- 1 and either sufentanil (TCI Cet 0.48 ng ml- 1) or remifentanil (TCI Cet 8 ng ml- 1). If HR dropped below 60 bpm, methylatropine (1 mg) was administered intravenously. Relative changes (∆) in MAP, HR, stroke volume (SV), CI and cerebral (SctO2) and peripheral (SptO2) tissue-oxygenation during induction of anaesthesia and after atropine administration were analysed.

RESULTS

The sufentanil group compared to the remifentanil group showed significantly less decrease in MAP (∆ = - 23 ± 13 vs. -36 ± 13 mmHg), HR (∆ = - 5 ± 7 vs. -10 ± 10 bpm), SV (∆ = - 23 ± 18 vs. -35 ± 19 ml) and CI (∆ = - 0.8 (- 1.5 to - 0.5) vs. -1.5 (- 2.0 to - 1.1) l min- 1 m- 2), while SctO2 (∆ = 9 ± 5 vs. 6 ± 4%) showed more increase with no difference in ∆SptO2 (∆ = 8 ± 7 vs. 8 ± 8%). Atropine caused higher ∆HR (13 (9 to 19) vs. 10 ± 6 bpm) and ∆CI (0.4 ± 0.4 vs. 0.2 ± 0.3 l min- 1 m- 2) in sufentanil vs. remifentanil-based anaesthesia, with no difference in ∆MAP, ∆SV and ∆SctO2 and ∆SptO2.

CONCLUSION

Induction of anaesthesia with propofol and sufentanil results in improved haemodynamic stability and higher SctO2 compared to propofol and remifentanil in patients having CABG. Administration of atropine might be useful to counteract or prevent the haemodynamic suppression associated with these opioids.

TRIAL REGISTRATION

Clinicaltrials.gov on June 7, 2013 (trial ID: NCT01871935 ).

Total Intravenous Anesthesia for the Small Animal Critical Patient

The practice of creating and maintaining general anesthesia using intravenous anesthetic drugs is defined as total intravenous anesthesia. Total intravenous anesthesia produces general anesthesia by selective drug properties that fulfill the 3 elements of anesthesia. Total intravenous anesthesia has potential application in veterinary emergency and critical care medicine. This article reviews the theory and application of total intravenous anesthesia and identifies possible application in emergency and critical care medicine.

Ultrasound-guided superior laryngeal nerve block assists in anesthesia for bronchoscopic surgical procedure: A case report of anesthesia for rigid bronchoscopy

INTRODUCTION

Evolving techniques in the field of therapeutic bronchoscopy have led to the return of rigid bronchoscopy in the treatment of complex central airway disease. Rigid bronchoscopy is typically performed under general anesthesia because of the strong stimulation caused by metal instruments. Anesthesia for rigid bronchoscopy is challenging to administer because anesthesiologists and interventionists share the same working channel: the airway. Previously reviewed anesthetic methods are used primarily for short procedures. Balanced anesthesia with ultrasound-guided superior laryngeal nerve (SLN) block and total intravenous anesthesia might provide anesthesia for a prolonged procedure and facilitate patient recovery.

PATIENT CONCERNS

A patient with obstructed endobronchial stent was referred for therapeutic rigid bronchoscopy, which requires deeper anesthesia than flexible bronchoscopy. There were concerns of the stronger stimulation of the rigid bronchoscopy, lengthy duration of the procedure, higher risk of hypoxemia, and the difficulty of mechanical ventilation weaning after anesthesia due to the patients co-morbidities.

DIAGNOSIS

A 66-year-old female patient presented with a history of breast cancer with lung metastases. Right main bronchus obstruction due to external compression of lung metastases was relieved through insertion of an endobronchial stent, but obstructive granulation developed after 4 months. Presence of the malfunctioning stent caused severe cough and discomfort. Removal of the stent by using a flexible bronchoscope was attempted twice but failed.

INTERVENTIONS

Regional anesthesia of the upper airway through ultrasound-guided SLN block combined with intratracheal 2% lidocaine spray was performed to assist in total intravenous anesthesia (TIVA) during rigid bronchoscopy.

OUTCOMES

The patient maintained steady spontaneous breathing throughout the procedure without laryngospasm, bucking, or desaturation. Emergence from anesthesia was smooth and rapid after propofol infusion was discontinued. The surgery lasted 2.5 hours without discontinuity, and no perioperative pulmonary or cardiovascular complications were noted.

CONCLUSION

Ultrasound-guided SLN block is a simple technique with a high success rate and low complication rate. Application of SLN block to assist TIVA provides sufficient anesthesia for lengthened therapeutic rigid bronchoscopy without interruption and facilitates patient recovery.

Perioperative Dexmedetomidine Fails to Improve Postoperative Analgesic Consumption and Postoperative Recovery in Patients Undergoing Lateral Thoracotomy for Thoracic Esophageal Cancer: A Randomized, Double-Blind, Placebo-Controlled Trial

Objectives

Dexmedetomidine is widely used as an adjunct to general anesthesia. In this study, we evaluated the effects of perioperative dexmedetomidine infusion on postoperative analgesia in patients undergoing lateral thoracotomy for thoracic esophageal cancer.

Methods

A total of 62 patients undergoing lateral thoracotomy for thoracic esophageal cancer were randomized to receive adjuvant therapy with either dexmedetomidine (0.5 μg/kg intravenous bolus injection for 10 min before induction of anesthesia, followed by continuous infusion of 0.2-0.4 μg/kg/h until the end of surgery, and 0.06 μg/kg/h for 5 days after surgery) or equal volumes of saline. Acute postoperative pain was treated with patient-controlled intravenous sufentanil and flurbiprofen axetil. The primary outcomes of this study were the numbers of analgesic requirements in the first postoperative 72 h.

Results

Perioperative dexmedetomidine did not decrease the numbers of analgesic requirements in the first postoperative 72 h (dexmedetomidine group: 12.14 ± 4.76, saline group: 10.89 ± 5.66; p=0.367). Likewise, the groups did not differ with respect to total postoperative analgesic requirements, postoperative pain, perioperative inflammation, blood cell count, incidence of adverse events, surgical recovery (assessed at postoperative days 2 and 5 using the surgical recovery scale), length of hospital stay, hospital cost, incidence of chronic pain, or quality of life. Notably, dexmedetomidine had beneficial effects on decreasing intraoperative opioid consumption and improving postoperative sleep quality. Discussion. Perioperative dexmedetomidine has limited analgesic benefits in lateral thoracotomy for esophageal cancer when added to an opioid-based multimodal anesthetic regimen but can reduce opioid consumption.

Measurement of mean systemic filling pressure after severe hemorrhagic shock in swine anesthetized with propofol-based total intravenous anesthesia: implications for vasopressor-free resuscitation

Background

Mean systemic filling pressure (Pmsf) is a quantitative measurement of a patient’s volume status and represents the tone of the venous reservoir. The aim of this study was to estimate Pmsf after severe hemorrhagic shock and cardiac arrest in swine anesthetized with propofol-based total intravenous anesthesia, as well as to evaluate Pmsf’s association with vasopressor-free resuscitation.

Methods

Ten healthy Landrace/Large-White piglets aged 10–12 weeks with average weight 20±1 kg were used in this study. The protocol was divided into four distinct phases: stabilization, hemorrhagic, cardiac arrest, and resuscitation phases. We measured Pmsf at 5–7.5 seconds after the onset of cardiac arrest and then every 10 seconds until 1 minute postcardiac arrest. During resuscitation, lactated Ringers was infused at a rate that aimed for a mean right atrial pressure of ≤4 mm Hg. No vasopressors were used.

Results

The mean volume of blood removed was 860±20 ml (blood loss, ~61%) and the bleeding time was 43.2±2 minutes while all animals developed pulseless electrical activity. Mean Pmsf was 4.09±1.22 mm Hg, and no significant differences in Pmsf were found until 1 minute postcardiac arrest (4.20±0.22 mm Hg at 5–7.5 seconds and 3.72±0.23 mm Hg at 55– 57.5 seconds; P=0.102). All animals achieved return of spontaneous circulation (ROSC), with mean time to ROSC being 6.1±1.7 minutes and mean administered volume being 394±20 ml.

Conclusions

For the first time, Pmsf was estimated after severe hemorrhagic shock. In this study, Pmsf remained stable during the first minute post-arrest. All animals achieved ROSC with goal-directed fluid resuscitation and no vasopressors.

Developing a personalized closed-loop controller of medically-induced coma in a rodent model

OBJECTIVE

Personalized automatic control of medically-induced coma, a critical multi-day therapy in the intensive care unit, could greatly benefit clinical care and further provide a novel scientific tool for investigating how the brain response to anesthetic infusion rate changes during therapy. Personalized control would require real-time tracking of inter- and intra-subject variabilities in the brain response to anesthetic infusion rate while simultaneously delivering the therapy, which has not been achieved. Current control systems for medically-induced coma require a separate offline model fitting experiment to deal with inter-subject variabilities, which would lead to therapy interruption. Removing the need for these offline interruptions could help facilitate clinical feasbility. In addition, current systems do not track intra-subject variabilities. Tracking intra-subject variabilities is essential for studying whether or how the brain response to anesthetic infusion rate changes during therapy. Further, such tracking could enhance control precison and thus help facilitate clinical feasibility.

APPROACH

Here we develop a personalized closed-loop anesthetic delivery (CLAD) system in a rodent model that tracks both inter- and intra-subject variabilities in real time while simultaneously controlling the anesthetic in closed loop. We tested the CLAD in rats by administrating propofol to control the electroencephalogram (EEG) burst suppression. We first examined whether the CLAD can remove the need for offline model fitting interruption. We then used the CLAD as a tool to study whether and how the brain response to anesthetic infusion rate changes as a function of changes in the depth of medically-induced coma. Finally, we studied whether the CLAD can enhance control compared with prior systems by tracking intra-subject variabilities.

MAIN RESULTS

The CLAD precisely controlled the EEG burst suppression in each rat without performing offline model fitting experiments. Further, using the CLAD, we discovered that the brain response to anesthetic infusion rate varied during control, and that these variations correlated with the depth of medically-induced coma in a consistent manner across individual rats. Finally, tracking these variations reduced control bias and error by more than 70% compared with prior systems.

SIGNIFICANCE

This personalized CLAD provides a new tool to study the dynamics of brain response to anesthetic infusion rate and has significant implications for enabling clinically-feasible automatic control of medically-induced coma.

An International Survey Evaluating Factors Influencing the Use of Total Intravenous Anaesthesia

The purpose of this study was to evaluate factors influencing the use of propofol-based total intravenous anaesthesia (TIVA) since despite TIVA being a well-established technique, it is used far less frequently than volatile anaesthesia. Questions were formulated after reviewing the literature for perceived disadvantages of TIVA and meeting with a focus group consisting of both senior and junior anaesthestists from our department. Once the survey had been formulated, specialist anaesthetists from professional colleges and societies from several countries were invited to complete the survey on an electronic web-based platform to allow evaluation of the respondent's rating of the importance of a range of factors in their decision not to use TIVA for a particular case. Basic descriptive statistics were determined using SPSS statistical software, while graphical depictions of data were handled using R for statistical analysis. A total of 763 survey responses were included in the final analysis and stratified according to the frequency of TIVA use. Among the infrequent users, issues such as additional effort, institutional preference, lack of real-time monitoring of propofol concentration, risk of missing drug delivery failure and increased turnaround time were among the top reasons mentioned. Interestingly, these issues were considered far less important among the frequent users when not choosing TIVA. We concluded that frequent and infrequent users respond quite differently to similar technical TIVA-related factors. Non-technical factors may play an important role in the infrequent user's decision not to use TIVA for a particular case.