Measured context-sensitive half-times of remifentanil and alfentanil

Postoperative Sedation in General Care Wards: A Retrospective Cohort Study

BACKGROUND

We hypothesized that deeper sedation in the postanesthesia care unit (PACU) increases the risk of subsequent sedation in general care wards (ward sedation) and that patients with ward sedation have more postoperative adverse events than those without ward sedation.

METHODS

We reviewed the health records of adult patients who underwent procedures with general anesthesia at Mayo Clinic from May 5, 2018, through December 31, 2020, and were discharged from the PACU to the general care ward. Patient groups were dichotomized as with ward sedation (Richmond Agitation-Sedation Scale [RASS], ≤-2) and without ward sedation (RASS, ≥-1) within the first 24 hours after PACU discharge. Multivariable logistic regression was used to assess the association between clinical variables and ward sedation.

RESULTS

A total of 23,766 patients were included in our analysis, of whom 1131 had ward sedation (incidence, 4.8 [Poisson 95% confidence interval, CI, 4.5-5.0]) per 100 patients after general anesthesia. Half of the ward sedation episodes occurred within 32 minutes after PACU discharge. The risk of ward sedation increased with the depth of PACU sedation. The odds ratios (95% CI) of ward sedation for patients with a PACU RASS score of -1 was 0.98 (0.75-1.27); -2, 1.87 (1.44-2.43); -3, 2.98 (2.26-3.93); and ≤-4, 3.97 (2.91-5.42). Adverse events requiring an emergency intervention occurred more often for patients with ward sedation (n = 92, 8.1%) than for those without ward sedation (n = 326, 1.4%; P < .001).

CONCLUSIONS

Among patients who met our criteria for PACU discharge, deeper sedation during anesthesia recovery was associated with an increased risk of ward sedation. Patients who had ward sedation had worse outcomes than those without ward sedation.

The Influence of Audiovisual Distraction on Pain Reduction During Transcatheter Aortic Valve Implantation Under Monitored Anesthesia Care: A Prospective Randomized Trial

OBJECTIVES

To investigate the effect of an audiovisual distraction system on the dose of remifentanil for perioperative sedation during transcatheter aortic valve implantation under monitored anesthesia care.

DESIGN

Single-center prospective randomized nonblinded study.

SETTING

Tertiary referral academic hospital.

PARTICIPANTS

Ninety patients who underwent transfemoral transcatheter aortic valve implantation between July 2019 and July 2021.

INTERVENTIONS

Patients were randomized to use either a novel audiovisual distraction system during the intervention (n = 45) or standard care without an audiovisual distraction system (n = 45).

MEASUREMENTS AND MAIN RESULTS

Standardized questionnaires were given to each patient at admission and before and after the intervention to assess their levels of anxiety. Primary endpoints were the average and peak infusion rates of remifentanil. All patients were considered for the final analysis according to an intention-to-treat design. No relevant differences in pre- and postinterventional anxiety status were observed between the groups. Similarly, there were no significant differences in reported pain scores (p = 0.364). The average infusion rate (p = 0.028) and peak infusion rate (p = 0.025) of remifentanil were lower in the group with an audiovisual distraction system.

CONCLUSIONS

Audiovisual distraction is a useful adjunct to reduce the dose of remifentanil under monitored anesthesia care during transcatheter aortic valve implantation. Larger studies are needed to evaluate potential positive effects on patient satisfaction, incidence of delirium, and possible economic benefits.

Caffeine administration to treat oversedation after general anesthesia: A retrospective analysis

STUDY OBJECTIVE

Our institution has adopted an informal practice of administering postoperative caffeine to expedite anesthesia recovery for patients with excessive sedation. This study aimed to determine whether caffeine administration was associated with improved sedation recovery and reduced risk of respiratory complications.

DESIGN

Single-center, retrospective, observational study.

SETTING

Quaternary medical center.

PATIENTS

We included adult patients who were admitted to a postanesthesia recovery care unit (PACU) after general anesthesia and had evidence of postoperative sedation (Richmond Agitation Sedation Score [RASS] < 0). Patients were seen from May 5, 2018, through December 31, 2020.

INTERVENTIONS

Patients were categorized according to caffeine administration (0 vs 250 mg).

MEASUREMENTS

Sedation was measured with RASS. To account for potential confounding, binary and ordinal logistic regression with inverse probability of treatment weighting (IPTW) were used to compare RASS and episodes of severe respiratory complications within 48 h after PACU discharge.

MAIN RESULTS

We identified 47,222 adult surgical patients with evidence of sedation in the PACU, and of these, 1892 (4.0%) were intravenously administered caffeine. Patients who received caffeine had more sedation in the PACU. In the IPTW-adjusted analysis, caffeine administration was associated with improved sedation scores after PACU discharge (ordinal logistic regression odds ratio [OR], 1.13 [95% CI, 1.00-1.28]; P = .04 for the first RASS score after PACU discharge) but increased risk of respiratory complications (OR, 2.99 [95% CI, 1.44-6.24]; P = .003) and emergency response team activation (OR, 7.18 [95% CI, 2.85-18.10]; P < .001).

CONCLUSIONS

In this observational study, caffeine administration during anesthesia recovery was associated with improved sedation scores. However, it was also associated with an increased risk of respiratory complications, possibly reflecting selection bias (ie, administering caffeine to higher-risk patients). Patients with signs of excessive sedation during anesthesia recovery may benefit from enhanced postoperative respiratory monitoring.

The association of intraoperative opioid dose with postanesthesia care unit outcomes in children: a retrospective study

PURPOSE

In children, the relationship between the dose of intraoperative opioid and postoperative outcomes is unclear. We examined the relationship between intraoperative opioid dose and postanesthesia care unit (PACU) pain scores and opioid and antiemetic administrations.

METHODS

We performed a single-institution retrospective cohort study. Patients who were aged < 19 yr, had an American Society of Anesthesiologists Physical Status of I-III, were undergoing one of 11 procedures under general anesthesia and without regional anesthesia, and who were admitted to the PACU were included. Patients were analyzed by quartiles of total intraoperative opioid dose using multivariable regression, adjusting for confounders including procedure. An exploratory analysis of opioid-free anesthetics was also performed.

RESULTS

Three thousand, seven hundred and thirty-three cases were included, and the mean age of included patients was 8.3 yr. After adjustment, there were no significant differences between the lowest and higher quartiles for first conscious pain score, mean pain score, PACU opioid dose, or PACU length of stay; in addition, estimated differences were small. Patients in higher quartiles were estimated to be more likely to receive antiemetics, significantly so for those in the second quartile. Patients in the lowest quartile received significantly more intraoperative nonopioid analgesics. In the exploratory analysis, no significant difference in PACU pain scores was found in cases without intraoperative opioids.

CONCLUSIONS

Children who received lower doses of intraoperative opioids did not have worse PACU pain outcomes but required fewer antiemetics and received greater numbers of nonopioid analgesics intraoperatively. These findings suggest that lower doses of intraoperative opioids may be administered to children as long as other analgesics are used.

Opioid infusions at different times of the day produce varying degrees of opioid-induced hyperalgesia

BACKGROUND

Opioids are metabolised by enzymes the activities of which vary with the circadian rhythm. We examined whether opioid infusions administered at different times of the day produce varying degrees of opioid-induced hyperalgesia (OIH) in animal experiments and clinical studies.

METHODS

Male Sprague-Dawley rats received remifentanil infusions (1 μg kg-1·min-1 for 1 h) at Zeitgeber times (ZT) 0, 4, 8, 12, 16, or 20 h. Rhythmicity of mechanical hypersensitivity was assayed after the infusion. Mechanical hypersensitivity, drug concentration, and metabolic enzyme activity of Wistar rats that received sufentanil (10 μg kg-1; four consecutive i.p. injections at 15-min intervals) or remifentanil infusion at ZT0 or ZT8 were assayed. Sixty patients who underwent abdominal laparoscopic surgery under general anaesthesia received remifentanil infusion (0.15 μg kg-1 min-1) and sufentanil injection (0.2 μg kg-1) at induction and skin incision, respectively. Postoperative pressure pain sensitivity, pain Numeric Rating Scale (NRS), drug concentrations, and nonspecific esterase activity were assessed.

RESULTS

Sprague-Dawley rats that received remifentanil infusion exhibited a robust rhythmic paw withdrawal threshold (JTK_CYCLE: P=0.001, Q=0.001, Phase=26). Wistar rats infused with remifentanil or sufentanil at ZT8 exhibited greater OIH (P<0.001) than those infused at ZT0, with higher blood concentrations (P<0.001) and lower metabolic enzyme activities (P=0.026 and P=0.028, respectively). Patients in the afternoon group exhibited higher pressure pain sensitivity at forearm (P=0.002), higher NRS (P<0.05), higher drug concentrations (sufentanil: P=0.037, remifentanil: P=0.005), and lower nonspecific esterase activity (P=0.024) than the morning group.

CONCLUSIONS

Opioid infusions administered at different times of day produced varying degrees of OIH, possibly related to circadian rhythms of metabolic enzyme activities.

CLINICAL TRIAL REGISTRATION

NCT05234697.

Efficacy, safety, and pharmacokinetics of MR13A11A, a generic of remifentanil, for pain management of Japanese patients in the intensive care unit: a double-blinded, fentanyl-controlled, randomized, non-inferiority phase 3 study

BACKGROUND

The aims of this study were to evaluate the efficacy, safety, and pharmacokinetics (PK) of continuous intravenous administration of remifentanil in mechanically ventilated patients in the intensive care unit (ICU).

METHODS

This was a multicenter, randomized, double-blinded, fentanyl-controlled, non-inferiority phase 3 study. Patients aged ≥ 20 years requiring 6 h to 10 days mechanical ventilation in an ICU and requiring pain relief were randomly assigned in a 1:1 ratio to receive either remifentanil (n = 98) or fentanyl (n = 98). Dose was titrated from an infusion rate of 1 mL/h (remifentanil: 0.025 µg/kg/min, fentanyl: 0.1 µg/kg/h) until the target level of analgesia (behavioral pain scale [BPS] ≤ 5 or numerical rating score [NRS] ≤ 3) was achieved by escalating the dose in 1 mL/h increasing. Administration was then adjusted to maintain the target level of analgesia until weaning from the ventilator. The primary endpoint was the proportion of patients who did not require rescue fentanyl. Safety was assessed according to standard procedures. PK of remifentanil in the arterial blood was assessed in 24 patients.

RESULTS

The proportion of patients achieving the primary endpoint in the remifentanil and fentanyl groups was 100% (92/92) and 97.8% (88/90), respectively. The difference between the groups was 2.2% (95% confidence interval, - 0.8-5.3) and non-inferiority of remifentanil to fentanyl was verified (p < 0.0001). The incidences of any adverse events in the remifentanil and fentanyl groups was 34 of 92 patients (37.0%) and 34 of 90 patients (37.8%), respectively. Adverse drug reactions was 12 in 92 patients (13.0%) and 15 in 90 patients (16.7%), respectively. In the PK analysis, blood remifentanil concentration decreased within 10 min to almost 50% of the end of administration, suggesting rapid offset of action following discontinuation of remifentanil.

CONCLUSIONS

Remifentanil can be used safely for pain management in mechanically ventilated Japanese patients in the ICU.

TRIAL REGISTRATION

Japan Registry of Clinical Trials, jRCT2080224954. Registered 20 November 2019, https://jrct.niph.go.jp/latest-detail/jRCT2080224954 .

Intraoperative Esketamine Is Effective at Reducing Acute Postoperative Pain in Bariatric Surgery Patients: a Randomized Control Trial

BACKGROUND

The analgesic effect and postoperative effects of esketamine are not yet clear in bariatric surgeries. Many bariatric surgery patients suffer from acute abdominal pain after surgery which leads to increased opioid use. This study aimed to determine whether intraoperative use of esketamine could reduce acute postoperative pain in bariatric surgery patients.

METHODS

We designed a randomized double-blinded controlled trial. Included patients between the ages of 18 and 50 years with a body mass index ≥27 kg/m2 and American Society of Anesthesiologists Physical Status of I-III, scheduled to undergo sleeve gastrectomy. We divided them into two groups, the control group which received a placebo, and the esketamine group which received a loading dose of esketamine 0.2 mg/kg and a maintenance dose of 0.2 mg/(kg·h) along with other anesthetic drugs during the surgery. After the surgery, they were assessed for Numerical Rating Scale (NRS) pain scores and Post Operative Nausea and Vomiting (PONV) scores, while other surgical data were recorded during the surgery.

RESULTS

We enrolled 68 patients, 52 females, and 16 males. The 0.5 h, 1 h, 2 h, 6 h, and 12 h NRS scores were significantly lower in the esketamine group compared to the control group, and the extra painkillers administered were significantly lower in the esketamine group (p<0.05).

CONCLUSION

Intraoperative use of esketamine can reduce acute postoperative pain in bariatric surgery patients. Further studies should explore whether the reduced pain is due to the anti-depressive effect of esketamine or purely the analgesic effect.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2100054038, https://www.chictr.org.cn/com/25/showproj.aspx?proj=142806 ).

Treatment of Acute Pain in Patients on Naltrexone: A Narrative Review

PURPOSE OF REVIEW

The tissue damage and trauma associated with surgery almost always result in acute postoperative pain. The intensity of postoperative pain can range from mild to severe. Naltrexone is suitable for patients who do not wish to be on an agonist treatment such as methadone or buprenorphine. However, naltrexone has been shown to complicate postoperative pain management.

RECENT FINDINGS

Multiple studies have found that the use of naltrexone can increase the opioid requirement for postoperative pain control. Other modalities exist that can help outside of opioids such as ketamine, lidocaine/bupivacaine, duloxetine, and non-pharmacological management can help manage pain. Multimodal pain regiments should also be employed in patients. In addition to traditional methods for postoperative pain management, other methods of acute pain control exist that can help mitigate opioid dependence and help control pain in patients who use naltrexone for their substance use disorders.

Effects of buprenorphine, methadone, and cariprazine on economic choice between remifentanil and food in squirrel monkeys

We recently reported an economic choice task in which squirrel monkeys chose between differing amounts of remifentanil, a fast-acting opioid, or a food reward to develop a preclinical screen for evaluating potential pharmacotherapies for opioid dependence. Herein, two known opioid addiction treatments are evaluated using this task, as well as a potential new agent, cariprazine, a dopamine D2/D3 receptor partial agonist currently used to treat bipolar disorder and schizophrenia. Preclinical rodent studies suggest this class of compounds may reduce opiate self-administration. Squirrel monkeys were pretreated daily with clinically relevant doses of each compound during the five days of treatment evaluation using the economic choice task. Shifts in drug preference were measured as changes in subjects' indifference values, where the probability of drug and milk choice are equivalent. Buprenorphine produced a significant shift in indifference value between baseline and treatment weeks, indicating a decrease in drug preference. Subjects treated with methadone and cariprazine did not show any significant shift in drug preference. Differences between the buprenorphine and methadone results likely reflect a lack of opioid dependence in the subjects. The cariprazine results suggest that it does not alter opioid reward in non-dependent primates over a five day period.

Efficacy and safety of remifentanil for endoscopic ultrasound-guided tissue acquisition: a single center retrospective study

BACKGROUND

Remifentanil is a rapid onset and rapid recovery opioid. The combination of remifentanil and propofol for deep sedation decreases the incidents of movement, cough, and hiccup. We evaluated the efficacy and safety of remifentanil during endoscopic ultrasound-guided tissue acquisition.

METHODS

We retrospectively reviewed patients in whom endoscopic ultrasound-guided tissue acquisition was performed for solid mass lesions of the upper gastrointestinal tract and adjacent organs. All patients were premedicated with midazolam (2 mg), and target-controlled infusion of propofol, opioid, and Bispectral Index (BIS) monitoring were administered as necessary to maintain moderate-to-deep sedation. The opioids used were a bolus of alfentanil or remifentanil infusion. The discharge time, consumption of propofol and opioid, adverse events, diagnostic accuracy, and sensitivity and specificity for malignancy, were compared.

RESULTS

Tissue acquisition was achieved in 123 patients (alfentanil group, n = 64; remifentanil group, n = 59). The discharge time of the remifentanil group (16.5 ± 3.2 min) was significantly shorter than that of the alfentanil group (19.0 ± 4.9 min, P = 0.001). The consumption of propofol, adverse events, diagnostic accuracy, sensitivity, and specificity for malignancy in the alfentanil group were not significantly different from those in the remifentanil group.

CONCLUSIONS

Use of alfentanil or remifentanil for target-controlled infusion of propofol-BIS monitoring can provide good sedative and diagnostic quality for endoscopic ultrasound-guided tissue acquisition. However, remifentanil resulted in faster recovery than alfentanil.

Effect of Dexmedetomidine Compared to Remifentanil During Bariatric Surgery on Postoperative Nausea and Vomiting: a Retrospective Study

PURPOSE

Postoperative nausea and vomiting (PONV) occurs frequently after bariatric surgery and is a major cause of adverse outcomes. This retrospective study investigated whether opioid-restricted total intravenous anesthesia using dexmedetomidine as a substitute for remifentanil can reduce PONV in bariatric surgery.

MATERIALS AND METHODS

The electronic medical records of adult patients who underwent laparoscopic bariatric surgery between January and December 2019 were reviewed. The patients were divided into two groups according to the agents used for anesthesia: Group D, propofol and dexmedetomidine; Group R, propofol and remifentanil.

RESULTS

A total of 134 patients were included in the analyses. The frequency of postoperative nausea was significantly lower in Group D than that in Group R until 2 h after discharge from the postanesthesia care unit (PACU) (P = 0.005 in the PACU, P = 0.010 at 2 h after PACU discharge) but failed to significantly reduce the overall high incidence rates of 60.5% and 65.5%, respectively (P = 0.592). Postoperative pain score was significantly lower in Group D until 6 h after PACU discharge. The rates of rescue antiemetic and analgesic agent administration in the PACU were significantly lower in Group D than those in Group R.

CONCLUSION

Opioid-restricted total intravenous anesthesia using dexmedetomidine reduces postoperative nausea, pain score, antiemetic, and analgesic requirements in the immediate postoperative period after bariatric surgery.

Structural Modification in Anesthetic Drug Development for Prodrugs and Soft Drugs

Among the advancements in drug structural modifications, the increased focus on drug metabolic and pharmacokinetic properties in the anesthetic drug design process has led to significant developments. Drug metabolism also plays a key role in optimizing the pharmacokinetics, pharmacodynamics, and safety of drug molecules. Thus, in the field of anesthesiology, the applications of pharmacokinetic strategies are discussed in the context of sedatives, analgesics, and muscle relaxants. In this review, we summarize two approaches for structural optimization to develop anesthetic drugs, by designing prodrugs and soft drugs. Drugs that both failed and succeeded during the developmental stage are highlighted to illustrate how drug metabolism and pharmacokinetic optimization strategies may help improve their physical and chemical properties.

Epidural Oxycodone for Acute Pain

Epidural analgesia is commonly used in labour analgesia and in postoperative pain after major surgery. It is highly effective in severe acute pain, has minimal effects on foetus and newborn, may reduce postoperative complications, and enhance patient satisfaction. In epidural analgesia, low concentrations of local anaesthetics are combined with opioids. Two opioids, morphine and sufentanil, have been approved for epidural use, but there is an interest in evaluating other opioids as well. Oxycodone is one of the most commonly used opioids in acute pain management. However, data on its use in epidural analgesia are sparse. In this narrative review, we describe the preclinical and clinical data on epidural oxycodone. Early data from the 1990s suggested that the epidural administration of oxycodone may not offer any meaningful benefits over intravenous administration, but more recent clinical data show that oxycodone has advantageous pharmacokinetics after epidural administration and that epidural administration is more efficacious than intravenous administration. Further studies are needed on the safety and efficacy of continuous epidural oxycodone administration and its use in epidural admixture.

Effect of high‐flow nasal oxygen on postoperative oxygenation in obese patients: A randomized controlled trial

Background and Aim

Postoperative hypoxemia is common after general anesthesia in obese patients. We investigated if early application of high‐flow nasal oxygen (HFNO) improved postoperative oxygenation in obese patients compared with standard oxygen therapy following general anesthesia for laparoscopic bariatric surgery.

Methods

This was an open labeled randomized controlled trial conducted at a university hospital in Sweden between October 23, 2018 and February 11, 2020. The study was performed as a substudy within a previously published trial. After ethics committee approval and written informed consent, 40 obese patients (body mass index [BMI] ≥ 35 kg m⁻²) scheduled for laparoscopic bariatric surgery were randomized to receive oxygen using a standard low‐flow nasal cannula (NC group) or HFNO at 40 L min⁻¹ (HF group) immediately upon arrival to the post‐anesthesia care unit. Flow rate (NC group) or FiO₂ (HF group) was titrated to reach an initial SpO₂ of 95%–98% after which settings were left unchanged. The primary outcome was PaO₂ at 60 min following postoperative baseline values. Secondary outcomes included PaCO₂, SpO₂, hemodynamic variables, and patient self‐assessed discomfort.

Results

Thirty‐four patients were available for analysis. PaO₂ was similar between groups at postoperative baseline. After 60 min, PaO₂ had increased to 12.6 ± 2.8 kPa in the NC group (n = 15) and 14.0 ± 2.7 kPa in the HF group (n = 19); (mean difference 1.4 kPa, 95% confidence interval −0.6 to 3.3; p = 0.16). There were no differences in PaCO₂, hemodynamic variables, or self‐assessed discomfort between groups after 60 min.

Conclusion

In obese patients, HFNO did not improve postoperative short‐term oxygenation compared with standard low‐flow oxygen following general anesthesia for laparoscopic bariatric surgery.

Effect of Remifentanil on Postoperative Vomiting After Strabismus Surgery in Preschool Children: A Prospective Randomized Controlled Trial

Background

Strabismus surgery and the use of opioid are risk factors of postoperative vomiting. We evaluated whether there is a dose-dependent effect of remifentanil on the incidence of postoperative vomiting.

Methods

Sixty pediatric patients who were scheduled for strabismus surgery were enrolled. Patients were randomly divided into three groups; Group H (high-dose remifentanil group), Group L (low-dose remifentanil group), and Group C (control group). After endotracheal intubation, patients in the Group H and L received an intravenous bolus dose of remifentanil of 1.0 μg/kg and 0.5 μg/kg over 2 min, respectively. Group H and L patients received a continuous infusion of remifentanil (0.1 μg/kg/min) during the surgery. The patients in Group C did not have any dose of remifentanil. Intravenous fentanyl (1 µg/kg) was administered to the patients for postoperative pain control.

Results

The primary outcome was a difference of the incidence of postoperative vomiting within 24 hours after surgery. There was no significant difference in incidence of postoperative vomiting between three groups. The degree of emergence agitation and postoperative pain did not show any significant difference between three groups.

Conclusions

The intraoperative administration of remifentanil did not show dose-dependent effect on postoperative vomiting in pediatric strabismus surgery.

Hemodynamic Impact of Drug Interactions With Epinephrine and Antipsychotics Under General Anesthesia With Propofol

OBJECTIVE

Antipsychotic drugs exhibit α-1 adrenergic receptor-blocking activity. When epinephrine and antipsychotic drugs are administered in combination, β-2 adrenergic effects are thought to predominate and induce hypotension. This study aimed to assess hemodynamic parameters in patients regularly taking antipsychotics who were administered epinephrine-containing lidocaine under general anesthesia in a dental setting.

METHODS

Thirty patients taking typical and/or atypical antipsychotics and scheduled for dental procedures under general anesthesia were enrolled. Five minutes after tracheal intubation, baseline systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and percutaneous oxygen saturation (SpO2) measurements were taken. The SBP, DBP, HR, and SpO2 measurements were repeated 2, 4, 6, 8, and 10 minutes after the injection of 1.8 mL of 2% lidocaine (36 mg) with 1:80,000 epinephrine (22.5 mcg) via buccal infiltration.

RESULTS

Differences between the baseline measurements and those of each time point were analyzed using Dunnett test, and no statistically significant changes were observed.

CONCLUSIONS

Our findings demonstrate that the use of epinephrine at a clinically relevant dose of 22.5 mcg for dental treatment under general anesthesia is unlikely to affect the hemodynamic parameters of patients taking antipsychotic medications.

Differential behavioral functioning in the offspring of rats with high vs. low self-administration of the opioid agonist remifentanil

Opioid use disorder (OUD) has a variety of adverse effects on both the users and their offspring. In the current study, a random group of Sprague-Dawley rats (25 females and 15 males) were tested for intravenous self-administration of the opioid agonist remifentanil to determine the range of acquisition for opioid. One-month after the end of self-administration of remifentanil, rats with the highest intake were mated together and rats with lowest intake were mated together. Then, the offspring of the two groups were tested for anxiety-like behavior, locomotor activity, nociception and intravenous remifentanil self-administration. The parents showed a range of remifentanil self-administration, especially in the female rats. The offspring of the parents with low and high remifentanil self-administration showed significant differences in specific behavioral functions. On the hotplate test of nociception, the female offspring parents with high remifentanil self-administration had significantly longer hotplate latencies, indicating reduced nociception, than the female offspring of parents with low remifentanil-self-administration, whereas there was no difference in the male offspring of low and high responding parents. In the elevated plus maze test of anxiety-like behavior, the offspring of the parents with high remifentanil intake showed more anxiety-like behavior than the offspring of the parents with low remifentanil intake regardless of sex. Locomotor activity was not significantly different. Interestingly, no significant differences in remifentanil self-administration in the offspring of parents with low and high remifentanil self-administration were detected. Overall, our data suggest a considerable range in remifentanil self-administration in rats and the offspring of rats with high opioid self-administration exhibit different behaviors vs offspring of rats with low opioid self-administration.

Effects of Propofol versus Sevoflurane on Postoperative Pain and Neuroendocrine Stress Response in Oocyte Pickup Patients

Background

Pain aggravates the autonomic response to stress and raises neuroendocrine stress hormone levels. We compared the effects of propofol and sevoflurane on postoperative pain and neuroendocrine stress hormones. A prospective, randomized, and controlled trial was conducted with 60 patients.

Methods

We randomly allocated patients to groups P (remifentanil/propofol, n = 30) and S (remifentanil/sevoflurane, n = 30). Preoperative blood samples were taken to measure serum adrenocorticotropic hormone (ACTH), corticotropin-releasing hormone (CRH), glucagon, cortisol, aldosterone, and prostaglandin E2 (PGE2) levels. Intraoperatively and postoperatively, clinical parameters were monitored at different time points. The hormone levels were again measured in the follicular fluid and blood postoperatively.

Result

Demographic data were similar. The preoperative serum aldosterone levels were significantly higher in group P (p=0.001). Preoperative and postoperative serum ACTH, glucagon, cortisol, and PGE2 levels were significantly different in group P (p=0.009, p=0.004, p=0.029, and p=0.002); serum ACTH, glucagon, and PGE2 levels increased while serum cortisol levels decreased postoperatively. In group S, serum CRH and aldosterone levels, both increased in the postoperative period compared to the preoperative (p=0.001, p=0.006). Postoperatively, glucagon and PGE2 levels were both higher in group P than group S (p=0.019, p=0.015). In postoperative follicular fluid, glucagon and PGE2 levels were higher in group P, while cortisol levels were higher in group S (p=0.001, p=0.007, and p=0.001).

Conclusion

The effects of anesthetic agents were different. In group P, in the preoperative and postoperative evaluation, ACTH, glucagon, and PGE2 increased postoperatively, while cortisol decreased. In group S, aldosterone and CRH increased postoperatively. Glucagon and PG E2 were higher in group P than S, postoperatively.

Effects of capnometry monitoring during recovery in the post-anaesthesia care unit: a randomized controlled trial in adults (CAPNOSSPI)

PURPOSE

Continuous capnography should be used on patients admitted to post-anaesthesia care units (PACUs) with endotracheal tubes, but this monitoring is not always performed. Optimized ventilation in the PACU could be part of the global standards of practice to maintain the benefits of perioperative ventilation. The main objective was to study the rate of patients with alveolar hypoventilation before tracheal extubation or Laryngeal Mask Airway (LMA) removal upon the measurement of continuous capnography.

METHODS

In this prospective, parallel-group, randomized controlled study, we enrolled adult patients admitted to the PACU after general anaesthesia with an endotracheal tube or LMA in place. Patients were randomly assigned to two groups: in the Capno + group, nurses managed the patients with access to the capnometer and end-tidal carbon dioxide pressure (PETCO₂) measurements; in the Capno- group, nurses monitored the patients without seeing PETCO₂ measurements. The primary outcome was the percentage of patients with PETCO₂ measurements above 45 mm Hg during the minute before extubation. Secondary endpoints included the delay in recovering spontaneous breathing, rate of hypoxemia, delay before extubation, and length of stay in the PACU.

RESULTS

Forty-eight patients were randomized into the two groups. The percentage of patients with PETCO₂ > 45 mm Hg the minute before extubation was significantly decreased in the Capno + group (83.3% versus 54,1% in the Capno- and Capno + groups respectively, p = 0.029). There were no significant differences concerning secondary endpoints.

CONCLUSIONS

The use of PETCO₂ monitoring improves patient safety by decreasing the incidence of CO₂ retention during recovery from general anaesthesia. This study suggests that this monitoring should be integrated in the PACU. The risk of hypoxemia can also be prevented through the early recognition of apnoea.Clinical Trial registry: clinicaltrial.gov. identifier: NCT03370081.

Remifentanil infusion during desflurane anesthesia reduces tissue blood flow while maintaining blood pressure and tissue oxygen tension in the masseter muscle and mandibular bone marrow

The aim of this study was to compare changes in tissue blood flow and tissue oxygen tension in the masseter muscle and mandibular bone marrow induced by remifentanil under desflurane or sevoflurane anesthesia. Eleven male tracheotomized Japan White rabbits were anesthetized with desflurane or sevoflurane under mechanical ventilation. The order of the inhalation of desflurane or sevoflurane was randomized. Desflurane or sevoflurane was administered at 1.0 minimum alveolar concentration and remifentanil was infused at 0.4 µg/kg/min. Observed variables included heart rate (HR), blood pressure (BP), common carotid artery blood flow (CCBF), mandibular bone marrow tissue blood flow (BBF), masseter muscle tissue blood flow (MBF), mandibular bone marrow tissue oxygen tension (PbO₂), and masseter muscle tissue oxygen tension (PmO₂). Two way repeated measures ANOVA showed no interaction between volatile anesthetics and remifentanil infusion except for MBF. There were significant differences in HR, SBP, DBP, MAP and CCBF between desflurane and sevoflurane groups. There were also significant differences in HR, SBP, DBP, MAP, CCBF, BBF and PbO₂ before, during and after remifentanil infusion. Desflurane reduced tissue blood flow in the masseter muscle and mandibular bone marrow while better maintained HR and BP than sevoflurane. Under remifentanil infusion, although both anesthetics reduced tissue blood flow, tissue oxygen tension was maintained in masseter muscle and mandibular bone marrow.

Remifentanil for Procedural Sedation and Analgesia in Central Venous Catheter Insertion: A Randomized, Controlled Trial

OBJECTIVE

Central venous catheter (CVC) insertion is a common practice for anesthetists, but this invasive procedure generates anxiety and pain in patients that are often underestimated. We compared target-controlled infusion of remifentanil and local lidocaine infiltration with placebo and local lidocaine infiltration to decrease pain scores during CVC placement.

MATERIALS AND METHODS

We included conscious, adult patients without contraindication to remifentanil or lidocaine. We excluded pregnant women, emergency situations, and opioid abuse. Patients requiring CVC were randomly assigned, using computer-generated allocation numbers stored in sealed envelopes, to receive target-controlled infusion of remifentanil or placebo-all patients received local anesthesia with lidocaine. All patients were hospitalized in a recovery room or intensive care unit, monitored, and received 4 L/min of oxygen.The primary outcome was global pain (Verbal Numeric Rating Pain Scale) during the procedure. Secondary outcomes were pain perceived at every stage of the procedure, anxiety, patient satisfaction, operational ease, and side effects.

RESULTS

In this double-blind study, we included 90 patients (split into 2 groups of 45 patients). Global pain was significantly reduced in the remifentanil group: 20 of 100 (95% confidence interval, 16-40) versus 50 of 100 (95% confidence interval, 40-60) in the placebo group; P=0.0009. No major adverse events were observed during this study, and there were no significant differences between both groups regarding side effects.

DISCUSSION

Target-controlled infusion of remifentanil is an effective drug to reduce pain during CVC insertion in association with lidocaine-based local anesthesia, in conscious patients.

Optimal effect-site concentration of remifentanil to prevent hemodynamic changes during nasotracheal intubation using a video laryngoscope

Background

Nasotracheal intubation is the most commonly used method to secure the field of view when performing surgery on the oral cavity or neck. Like orotracheal intubation, nasotracheal intubation uses a laryngoscope. Hemodynamic change occurs due to the stimulation of the sympathetic nervous system. Recently, video laryngoscope with a camera attached to the end of the direct laryngoscope blade has been used to minimize this change. In this study, we investigated the optimal effect-site concentration (Ce) of remifentanil for minimizing hemodynamic responses during nasotracheal intubation with a video laryngoscope.

Methods

Twenty-one patients, aged between 19 and 60 years old, scheduled for elective surgery were included in this study. Anesthesia was induced by slowly injecting propofol. At the same time, remifentanil infusion was initiated at 3.0 ng/ml via target-controlled infusion (TCI). When remifentanil attained the preset Ce, nasotracheal intubation was performed using a video laryngoscope. The patient's blood pressure and heart rate were checked pre-induction, right before and after intubation, and 1 min after intubation. Hemodynamic stability was defined as an increase in systolic blood pressure and heart rate by 20% before and after nasotracheal intubation. The response of each patient determined the Ce of remifentanil for the next patient at an interval of 0.3 ng/ml.

Results

The Ce of remifentanil administered ranged from 2.4 to 3.6 ng/ml for the patients evaluated. The estimated optimal effective effect-site concentrations of remifentanil were 3.22 and 4.25 ng/ml, that were associated with a 50% and 95% probability of maintaining hemodynamic stability, respectively.

Conclusion

Nasotracheal intubation using a video laryngoscope can be successfully performed in a hemodynamically stable state by using the optimal remifentanil effect-site concentration (Ce₅₀, 3.22 ng/ml; Ce₉₅, 4.25 ng/ml).

Intraoperative Remifentanil Infusion and Postoperative Pain Outcomes After Cardiac Surgery-Results from Secondary Analysis of a Randomized, Open-Label Clinical Trial

DESIGN

Report of secondary pain outcomes from a prospective, randomized, open-label clinical trial that compared remifentanil and fentanyl on perioperative hyperglycemic response in cardiac surgery.

SETTING

Single institution, tertiary university hospital.

PARTICIPANTS

The study comprised 116 adult elective cardiac surgical patients.

INTERVENTIONS

Participants were randomly assigned to receive either intermittent fentanyl boluses (F) or continuous remifentanil infusion (R) intraoperatively.

MEASUREMENTS AND MAIN RESULTS

Postoperative pain was evaluated with pain scores every 6 hours for 48 hours. Pain threshold to mechanical stimuli was measured around the sternotomy incision at 48 and 96 hours. The development of chronic pain was assessed using the numeric rating scale at 1, 3, 6, and 12 months after discharge. The final analysis included 106 patients. Pain scores and wound hyperalgesia were not significantly different postoperatively between the groups. The incidence of chronic pain at 3 months was comparable in both groups (61% in group F v 58% in group R; p = 0.79). Pain of more-than-mild degree was seen in 13 (32%) patients in group F and 8 (19%) in group R (p = 0.25) at 3 months. Median pain scores were not significantly different between the groups at 1, 3, 6, and 12 months after discharge from the hospital.

CONCLUSIONS

The present study's findings suggested that intraoperative remifentanil infusion does not significantly worsen pain outcomes in patients undergoing elective cardiac surgery.

Pain management during labor and vaginal birth

Neuraxial analgesia provides excellent pain relief in labor. Optimizing initiation and maintenance of neuraxial labor analgesia requires different strategies. Combined spinal-epidurals or dural puncture epidurals may offer advantages over traditional epidurals. Ultrasound is useful in certain patients. Maintenance of analgesia is best achieved with a background regimen (either programmed intermittent boluses or a continuous epidural infusion) supplemented with patient-controlled epidural analgesia and using dilute local anesthetics combined with opioids such as fentanyl. Nitrous oxide and systemic opioids are also used for pain relief. Nitrous oxide may improve satisfaction despite variable effects on pain. Systemic opioids can be administered by healthcare providers or using patient-controlled analgesia. Appropriate choice of drug should take into account the stage and progression of labor, local safety protocols, and maternal and fetal/neonatal side effects. Pain in labor is complex, and women should fully participate in the decision-making process before any one modality is selected.

Effect of anesthesia on motor responses evoked by spinal neural prostheses during intraoperative procedures

OBJECTIVE

The overall goal of this study was to investigate the effects of various anesthetic protocols on the intraoperative responses to intraspinal microstimulation (ISMS). ISMS is a neuroprosthetic approach that targets the motor networks in the ventral horns of the spinal cord to restore function after spinal cord injury. In preclinical studies, ISMS in the lumbosacral enlargement produced standing and walking by activating networks controlling the hindlimb muscles. ISMS implants are placed surgically under anesthesia, and refinements in placement are made based on the evoked responses. Anesthesia can have a significant effect on the responses evoked by spinal neuroprostheses; therefore, in preparation for clinical testing of ISMS, we compared the evoked responses under a common clinical neurosurgical anesthetic protocol with those evoked under protocols commonly used in preclinical studies.

APPROACH

Experiments were conducted in seven pigs. An ISMS microelectrode array was implanted in the lumbar enlargement and responses to ISMS were measured under three anesthetic protocols: (1) isoflurane, an agent used pre-clinically and clinically, (2) total intravenous anesthesia (TIVA) with propofol as the main agent commonly used in clinical neurosurgical procedures, (3) TIVA with sodium pentobarbital, an anesthetic agent used mostly preclinically. Responses to ISMS were evaluated based on stimulation thresholds, movement kinematics, and joint torques. Motor evoked potentials (MEP) and plasma concentrations of propofol were also measured.

MAIN RESULTS

ISMS under propofol anesthesia produced large and functional responses that were not statistically different from those produced under pentobarbital anesthesia. Isoflurane, however, significantly suppressed the ISMS-evoked responses.

SIGNIFICANCE

This study demonstrated that the choice of anesthesia is critical for intraoperative assessments of motor responses evoked by spinal neuroprostheses. Propofol and pentobarbital anesthesia did not overly suppress the effects of ISMS; therefore, propofol is expected to be a suitable anesthetic agent for clinical intraoperative testing of an intraspinal neuroprosthetic system.

The Use of Volatile Anesthetics as Sedatives for Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) remains to pose a high morbidity and mortality without any targeted therapies. Sedation, usually given intravenously, is an important part of clinical practice in intensive care unit (ICU), and the effect of sedatives on patients’ outcomes has been studied intensively. Although volatile anesthetics are not routine sedatives in ICU, preclinical and clinical studies suggested their potential benefit in pulmonary pathophysiology. This review will summarize the current knowledge of ARDS and the role of volatile anesthetic sedation in this setting from both clinical and mechanistic standpoints. In addition, we will review the infrastructure to use volatile anesthetics.

Efficacy of a Dexmedetomidine-Remifentanil Combination Compared with a Midazolam-Remifentanil Combination for Conscious Sedation During Therapeutic Endoscopic Retrograde Cholangio-Pancreatography: A Prospective, Randomized, Single-Blinded Preliminary Trial

BACKGROUND

Dexmedetomidine as a conscious sedative exhibits both analgesia and respiratory sparing effects.

AIMS

We evaluated and compared the sedative effect and the safety of a dexmedetomidine-remifentanil (DR) regimen with a midazolam-remifentanil (MR) combination during the endoscopic retrograde cholangio-pancreatography (ERCP) requiring conscious sedation.

METHODS

One-hundred and ninety-eight patients were randomized and divided into two groups. A bolus of midazolam (0.05 mg kg^-1) was injected intravenously for MR group, and dexmedetomidine (1 μg kg^-1) was pumping for 10 min for DR group. Next, an initial loading dose of 1 μg kg^-1 and 0.05-0.2 μg kg^-1 min^-1 of remifentanil was administered in all patients. Hemodynamic and respiratory changes, Ramsay Sedation Scale, Visual Analogue Scale, endoscopist and patient satisfaction were assessed. Furthermore, adverse events as well as recovery time and discharge time were rated.

RESULTS

Patient satisfaction scores were significantly higher in the DR group compared with MR group. The occurrence of desaturation was statistically higher, and the operation time was longer in the MR group. Although no statistically significant values could be determined between the two groups about amnesia and need of additional drug, the DR group was found to require a significantly reduced amount of extra midazolam. Furthermore, nausea during catheterization of oropharynx was found to be more pronounced in the DR group.

CONCLUSIONS

The dexmedetomidine-remifentanil protocol provided a parallel sedative efficacy and improved respiratory sparing effects. The higher patient satisfaction scores potentially offer a more reproducible ERCP quality. Adding dexmedetomidine to remifentanil can be used safely as a conscious sedation method during ERCP.

Effects of Esmolol on the Esophagogastric Junction: A Double-Blind, Randomized, Crossover Study on 14 Healthy Volunteers

BACKGROUND

Passive regurgitation may occur throughout the perioperative period, increasing the risk for pulmonary aspiration and postoperative pulmonary complications. Hypnotics and opioids, especially remifentanil, that are used during anesthesia have been shown to decrease the pressure in the esophagogastric junction (EGJ), that otherwise acts as a barrier against passive regurgitation of gastric contents. Esmolol, usually used to counteract tachycardia and hypertension, has been shown to possess properties useful during general anesthesia. Like remifentanil, the β-1-adrenoreceptor antagonist may be used to attenuate the stress reaction to tracheal intubation and to modify perioperative anesthetic requirements. It may also reduce the need for opioids in the postoperative period. Its action on the EGJ is however unknown.The aim of this trial was to compare the effects of esmolol and remifentanil on EGJ pressures in healthy volunteers, when administrated as single drugs.

METHODS

Measurements of EGJ pressures were made in 14 healthy volunteers using high-resolution solid-state manometry. Interventions were administered in a randomized sequence and consisted of esmolol that was given IV as a bolus dose of 1 mg/kg followed by an infusion of 10 μg·kg·minute over 15 minutes, and remifentanil with target-controlled infusion of 4 ng/mL over 15 minutes. Interventions were separated by a 20-minute washout period. Analyses of EGJ pressures were performed at baseline, and during drug administration at 2 (T2) and 15 minutes (T15). The primary outcome was the inspiratory EGJ augmentation, while the inspiratory and expiratory EGJ pressures were secondary outcomes.

RESULTS

There was no effect on inspiratory EGJ augmentation when comparing remifentanil and esmolol (mean difference -4.0 mm Hg [-9.7 to 1.7]; P= .15). In contrast, remifentanil significantly decreased both inspiratory and expiratory pressures compared to esmolol (-12.2 [-18.6 to -5.7]; P= .003 and -8.0 [-13.3 to -2.8]; P= .006).

CONCLUSIONS

Esmolol, compared with remifentanil, does not affect EGJ function. This may be an advantage regarding passive regurgitation and esmolol may thus have a role to play in anesthesia where maintenance of EGJ barrier function is of outmost importance.

The RESPITE trial: remifentanil intravenously administered patient-controlled analgesia (PCA) versus pethidine intramuscular injection for pain relief in labour: study protocol for a randomised controlled trial

BACKGROUND

The commonest opioid used for pain relief in labour is pethidine (meperidine); however, its effectiveness has long been challenged and the drug has known side effects including maternal sedation, nausea and potential transfer across the placenta to the foetus. Over a third of women receiving pethidine require an epidural due to inadequate pain relief. Epidural analgesia increases the risk of an instrumental vaginal delivery and its associated effects. Therefore, there is a clear need for a safe, effective, alternative analgesic to pethidine. Evidence suggests that remifentanil patient-controlled analgesia (PCA) reduces epidural conversion rates compared to pethidine; however, no trial has yet investigated this as a primary endpoint. We are, therefore, comparing pethidine intramuscular injection to remifentanil PCA in a randomised controlled trial.

METHODS/DESIGN

Women in established labour, requesting systemic opioid pain relief, will be randomised to either intravenously administered remifentanil PCA (intervention) or pethidine intramuscular injection (control) in an unblinded, 1:1 individual randomised trial. Following informed consent, 400 women in established labour, who request systemic opioid pain relief, from NHS Trusts across England will undergo a minimised randomisation by a computer or automated telephone system to either pethidine or remifentanil. In order to balance the groups this minimisation is based on four parameters; parity (nulliparous versus multiparous), maternal age (<20, 20 < 30, 30 < 40, 40+ years), ethnicity (South Asian (Pakistani/Indian/Bangladeshi) versus Other) and induced versus spontaneous labour. The effectiveness of pain relief provided by each technique will be recorded every 30 min after time zero, until epidural placement, delivery or transfer to theatre, quantified by Visual Analogue Scale. Incidence of maternal side effects including sedation, delivery mode, foetal distress requiring delivery, neonatal status at delivery and rate of initiation of breastfeeding within the first hour of birth will also be recorded. Maternal satisfaction with her childbirth experience will be determined by a postpartum questionnaire prior to discharge from the delivery ward.

DISCUSSION

The RESPITE trial's primary outcome is the proportion of women who have an epidural placed for pain relief in labour in each arm.

TRIAL REGISTRATION

Current Controlled Trials registration number: ISRCTN29654603 . Registered on 23 July 2013.

Remifentanil in electroconvulsive therapy: a systematic review and meta-analysis of randomized controlled trials

In electroconvulsive therapy (ECT), remifentanil is often used concurrently with anesthetics. The objective of this study was to provide an up-to-date and comprehensive review on how the addition of remifentanil to anesthetics affects seizure duration and circulatory dynamics in mECT. We performed a meta-analysis of RCTs that investigated seizure duration and circulatory dynamics in patients treated with ECT using anesthetics alone (non-remifentanil group) and with anesthetics plus remifentanil (remifentanil group). A total of 13 RCTs (380 patients and 1024 ECT sessions) were included. The remifentanil group showed a significantly prolonged seizure duration during ECT compared to the non-remifentanil group [motor: 9 studies, SMD = 1.25, 95 % CI (0.21, 2.29), p = 0.02; electroencephalogram: 8 studies, SMD = 0.98, 95 % CI (0.14, 1.82), p = 0.02]. The maximum systolic blood pressure (SBP) was significantly reduced in the remifentanil group compared to the non-remifentanil group [7 studies, SMD = -0.36, 95 % CI (-0.65, 0.07), p = 0.02]. Substantial heterogeneity was observed for meta-analyses for seizure durations, but a pre-planned subgroup analysis revealed that seizure duration was prolonged only when the use of the anesthetic dose was reduced in the remifentanil group. The results of our study suggest that addition of remifentanil to anesthesia in ECT may lead to prolonged seizure duration when it allows the use of reduced anesthetic doses. Further, the addition of remifentanil was associated with reduced maximum SBP.

Severe respiratory depression and bradycardia before induction of anesthesia and onset of Takotsubo cardiomyopathy after cardiopulmonary resuscitation

A 69-year-old woman undergoing treatment for hypertension and epilepsy was scheduled to undergo cataract surgery. All preoperative examination results were within normal limits. Despite being tense, she walked to the operating room. Approximately 2 minutes after an intravenous line was established by an anesthesia resident, severe hypoxia and bradycardia developed, and she lost consciousness. Cardiopulmonary resuscitation was initiated immediately, and after 1 minute, she regained consciousness, and her breathing and circulation recovered. After admission to the intensive care unit, emergency coronary angiography was performed. The blood flow in all the coronary arteries was normal. However, a decrease in the apical left ventricular wall motion and an increase in the basal wall motion were observed. Based on these findings, Takotsubo cardiomyopathy was diagnosed. The wall motion gradually improved and the patient was discharged from the hospital on postoperative day 15. The respiratory depression and bradycardia were thought to be due to an inadvertent bolus of remifentanil. We surmised that the patient had received a slight amount of retained medication when the anesthesia resident established the intravenous line, which caused severe respiratory depression. It is important to note that adverse effects such as severe respiratory depression and bradycardia can be caused by even small doses of remifentanil.

Sedation with a remifentanil infusion to facilitate rapid awakening and tracheal extubation in an infant with a potentially compromised airway

Sedation is generally required during endotracheal intubation and mechanical ventilation in infants and children. While there are many options for the provision of sedation, the most commonly used agents such as midazolam and fentanyl demonstrate a context-sensitive half-life, which may result in a prolonged effect when these agents are discontinued following a continuous infusion. We present a 20-month-old infant who required endotracheal intubation due to respiratory failure following seizures. At the referring hospital, multiple laryngoscopies were performed with the potential for airway trauma. To maximize rapid awakening and optimize respiratory function surrounding tracheal extubation, sedation was transitioned from fentanyl and midazolam to remifentanil for 18–24 hours prior to tracheal extubation. The unique pharmacokinetics of remifentanil are presented in this study, its use in this clinical scenario is discussed, and its potential applications in the pediatric intensive care unit setting are reviewed.

Comparison of Dexmedetomidine and Remifentanil on Airway Reflex and Hemodynamic Changes during Recovery after Craniotomy

PURPOSE

During emergence from anesthesia for a craniotomy, maintenance of hemodynamic stability and prompt evaluation of neurological status is mandatory. The aim of this prospective, randomized, double-blind study was to compare the effects of dexmedetomidine and remifentanil on airway reflex and hemodynamic change in patients undergoing craniotomy.

MATERIALS AND METHODS

Seventy-four patients undergoing clipping of unruptured cerebral aneurysm were recruited. In the dexmedetomidine group, patients were administered dexmedetomidine (0.5 μg/kg) for 5 minutes, while the patients of the remifentanil group were administered remifentanil with an effect site concentration of 1.5 ng/mL until endotracheal extubation. The incidence and severity of cough and hemodynamic variables were measured during the recovery period. Hemodynamic variables, respiration rate, and sedation scale were measured after extubation and in the post-anesthetic care unit (PACU).

RESULTS

The incidence of grade 2 and 3 cough at the point of extubation was 62.5% in the dexmedetomidine group and 53.1% in the remifentanil group (p=0.39). Mean arterial pressure (p=0.01) at admission to the PACU and heart rate (p=0.04 and 0.01, respectively) at admission and at 10 minutes in the PACU were significantly lower in the dexmedetomidine group. Respiration rate was significantly lower in the remifentanil group at 2 minutes (p<0.01) and 5 minutes (p<0.01) after extubation.

CONCLUSION

We concluded that a single bolus of dexmedetomidine (0.5 μg/kg) and remifentanil infusion have equal effectiveness in attenuating coughing and hemodynamic changes in patients undergoing cerebral aneurysm clipping; however, dexmedetomidine leads to better preservation of respiration.

Pathophysiology, assessment, and management of pain in critically ill adults

PURPOSE

The pathophysiology of pain in critically ill patients, the role of pain assessment in optimal pain management, and pharmacologic and nonpharmacologic strategies for pain prevention and treatment are reviewed.

SUMMARY

There are many short- and long-term consequences of inadequately treated pain, including hyperglycemia, insulin resistance, an increased risk of infection, decreased patient comfort and satisfaction, and the development of chronic pain. Clinicians should have an understanding of the basic physiology of pain and the patient populations that are affected. Pain should be assessed using validated pain scales that are appropriate for the patient's communication status. Opioids are the cornerstone of pain treatment. The use of opioids, administered via bolus dosing or continuous infusion, should be guided by patient-specific goals of care in order to avoid adverse events. A multimodal approach to pain management, including the use of regional analgesia, may improve patient outcomes and decrease opioid-related adverse events, though there are limited relevant data in adult critically ill patient populations. Nonpharmacologic strategies have been shown to be effective adjuncts to pharmacologic regimens that can improve patient-reported pain intensity and reduce analgesic requirements. Analgesic regimens need to take into account patient-specific factors and be closely monitored for safety and efficacy.

CONCLUSION

Acute pain management in the critically ill is a largely underassessed and undertreated area of critical care. Opioids are the cornerstone of treatment, though a multimodal approach may improve patient outcomes and decrease opioid-related adverse events.