Recovery profiles from dexmedetomidine as a general anesthetic adjuvant in patients undergoing lower abdominal surgery

Postanesthesia Care Unit Recovery Time According to Volatile Anesthetic Used in Clinical Practice

BACKGROUND

Whether volatile anesthetic solubility affects postanesthesia recovery time in clinical practice is unclear. We investigated the association among 3 volatile agents and 2 clinically relevant outcomes-postanesthesia care unit (PACU) recovery time (time from PACU admission to fulfillment of discharge criteria) and oversedation (Richmond Agitation-Sedation Scale score ≤-3)-as a potential contributor to delaying PACU discharge. The volatile agents studied were isoflurane, desflurane, and sevoflurane. We hypothesized that increased solubility of the volatile agent (isoflurane versus desflurane or sevoflurane) would be associated with longer PACU recovery time and higher rates of oversedation.

METHODS

This retrospective observational study included adults (≥18 years) who underwent surgical procedures under general anesthesia with a volatile agent and were admitted to the PACU from May 5, 2018, to December 31, 2020. The primary outcome was PACU recovery time, and the secondary outcome was oversedation. PACU recovery time was log-transformed and analyzed with linear regression. Oversedation was analyzed by using logistic regression. To account for potential confounding, inverse probability of treatment weighting (IPTW) was used. Pairwise comparisons of the 3 agents were performed, with P < .017 (Bonferroni-adjusted) considered significant.

RESULTS

Of 47,847 patients included, 11,817 (24.7%) received isoflurane, 11,286 (23.6%) received desflurane, and 24,744 (51.7%) received sevoflurane. Sevoflurane had an estimated 4% shorter PACU recovery time (IPTW-adjusted median [interquartile range {IQR}], 61 [42-89] minutes) than isoflurane (64 [44-92] minutes) (ratio of geometric means [98.3% confidence interval {CI}], 0.96 [0.95-0.98]; P < .001). Differences in PACU recovery time between desflurane and the other agents were not significant. The IPTW-adjusted frequency of oversedation was 8.8% for desflurane, 12.2% for sevoflurane, and 16.7% for isoflurane; all pairwise comparisons were observed to be significant (odds ratio [98.3% CI], 0.70 [0.62-0.79] for desflurane versus sevoflurane, 0.48 [0.42-0.55] for desflurane vs isoflurane, and 0.69 [0.63-0.76] for sevoflurane versus isoflurane; all P < .001). Although oversedated patients had longer PACU recovery time, differences in the oversedation rate across agents did not result in meaningful differences in time to PACU recovery.

CONCLUSIONS

In clinical practice, only small, clinically unimportant differences in PACU recovery time were observed between the volatile anesthetics. Although oversedation was associated with increased PACU recovery time, differences in the rate of oversedation among agents were insufficient to produce meaningful differences in overall PACU recovery time across the 3 volatile agents. Practical attempts to decrease PACU recovery time should address factors other than volatile agent selection.

Taming Postoperative Delirium with Dexmedetomidine: A Review of the Therapeutic Agent's Neuroprotective Effects following Surgery

Postoperative delirium (POD) represents a perioperative neurocognitive disorder that has dreaded ramifications on a patient's recovery from surgery. Dexmedetomidine displays multiple mechanisms of neuroprotection to assist in preventing POD as a part of a comprehensive anesthetic care plan. This review will cover dexmedetomidine's pharmacological overlap with the current etiological theories behind POD along with pre-clinical and clinical studies on POD prevention with dexmedetomidine. While the body of evidence surrounding the use of dexmedetomidine for POD prevention still requires further development, promising evidence exists for the use of dexmedetomidine in select dosing and circumstances to enhance recovery from surgery.

Effect of dexmedetomidine on the Montreal Cognitive Assessment in older patients undergoing pulmonary surgery

Objective

We investigated the effect of dexmedetomidine anesthesia on postoperative cognitive function after pulmonary surgery.

Methods

A blinded, prospective, randomized, placebo-controlled study was performed on 60 patients (age range 65–74 years) undergoing lobectomy by video-assisted thoracoscopic surgery (29 in the dexmedetomidine group; 31 in the placebo group). Dexmedetomidine group patients received dexmedetomidine, and placebo group patients received an equal volume of physiological saline 20 minutes before anesthesia induction. Cognitive function was evaluated using the Montreal Cognitive Assessment 1 day before surgery and on postoperative day (POD)1, POD3, and POD7. The regional cerebral oxygen saturation (rSO₂) was monitored continuously by near-infrared spectroscopy before anesthesia.

Results

The Montreal Cognitive Assessment score was significantly different between the two groups on POD1 (dexmedetomidine 26.4  ±  0.73 vs. placebo 25.5 ± 0.96) and POD3 (dexmedetomidine 27.1 ± 0.79 vs. placebo 26.6 ± 0.80). Specifically, attention and orientation scores were increased in the dexmedetomidine group on POD1 and POD3. The rSO₂ was not significantly different between the dexmedetomidine and placebo groups.

Conclusion

Dexmedetomidine given before induction of anesthesia could reduce the risk of postoperative cognitive dysfunction and might not decrease rSO₂. Hence, dexmedetomidine could be employed in pulmonary surgical procedures, especially for older patients with a high risk of cognitive dysfunction.

Delayed Emergence from Anesthesia: What We Know and How We Act

The emergence from anesthesia is the stage of general anesthesia featuring the patient's progression from the unconsciousness status to wakefulness and restoration of consciousness. This complex process has precise neurobiology which differs from that of induction. Despite the medications commonly used in anesthesia allow recovery in a few minutes, a delay in waking up from anesthesia, called delayed emergence, may occur. This phenomenon is associated with delays in the operating room, and an overall increase in costs. Together with the emergence delirium, the phenomenon represents a manifestation of inadequate emergence. Nevertheless, in delayed emergence, the transition from unconsciousness to complete wakefulness usually occurs along a normal trajectory, although slowed down. On the other hand, this awakening trajectory could proceed abnormally, possibly culminating in the manifestation of emergence delirium. Clinically, delayed emergence often represents a challenge for clinicians who must make an accurate diagnosis of the underlying cause to quickly establish appropriate therapy. This paper aimed at presenting an update on the phenomenon, analyzing its causes. Diagnostic and therapeutic strategies are addressed. Finally, therapeutic perspectives on the "active awakening" are reported.

Evaluation of the perioperative effects of dexmedetomidine on tympanoplasty operations

PURPOSE

This randomized double-blind study aimed to evaluate the effects of dexmedetomidine on hemodynamic parameters and the quality of surgery and recovery criteria in tympanoplasty operations.

MATERIALS AND METHODS

A total of 75 patients 18-55 years undergoing tympanoplasty, who were graded as American Society of Anesthesiologists physical status I-II, were randomly divided into three groups. Group 1 included patients receiving remifentanil alone, Group 2 included patients receiving dexmedetomidine + remifentanil and Group 3 included patients receiving dexmedetomidine + ½ remifentanil. Anesthesia was induced with propofol and cisatracurium. For maintenance of anesthesia, a mixture of 2-2.5% sevoflurane, 40-60% oxygen/air was used. The groups were compared in terms of hemodynamic parameters, surgical area, recovery criteria, modified Aldrete, pain scores, additional analgesic requirements and adverse effects.

RESULTS

Mean arterial pressure and heart rate values of Group 1 were higher at the time of intubation, incision, spontaneous breathing and extubation compared to Group 2 and Group 3. Surgical field satisfaction was higher in Group 2 and Group 3 than Group 1. Spontaneous breathing, eye opening and verbal cooperation times were shorter in Group 3 compared to Group 2. Eye opening and verbal cooperation times were longer in Group 2 compared to Group 1. The 30-minute modified Aldrete scores was higher in Group 3 compared to Group 1. There was no difference between the groups in terms of postoperative pain and adverse effects.

CONCLUSION

The use of dexmedetomidine during tympanoplasty operations may provide better hemodynamic control and surgical view, may provide faster recovery and may reduce remifentanil consumption.

Comparison of opioid-based and opioid-free TIVA for laparoscopic urological procedures in obese patients

BACKGROUND AND AIMS

Perioperative pain management in an obese patient is challenging. The incidence of respiratory depression is higher in obese patients and is exaggerated with opioids. We evaluated the efficacy of opioid-free anesthesia with propofol, dexmedetomidine, lignocaine, and ketamine in obese patients undergoing urological laparoscopic procedures with reference to postoperative analgesic consumption, hemodynamic stability, and respiratory depression.

MATERIAL AND METHODS

In this prospective, randomized, blinded controlled study, patients were randomized to receive either opioid-based (opioid group) or opioid-free (opioid-free group) anesthesia. Postoperative pain was assessed using visual analog score (VAS) 30 min after recovery, hourly for 2 h and every 4 hourly for 24 h. The primary outcomes studied were respiratory depression, mean analgesic consumption and time to rescue analgesia. Intraoperative hemodynamic parameters, mean SpO2, respiratory rate and postanesthesia care unit (PACU) discharge time were secondary objectives.

RESULTS

There were no differences in the demographic and intraoperative hemodynamic profile between the groups. Incidence of respiratory depression, defined as fall in saturation, was more in opioid-based group. Postoperative analgesic requirement (225 ± 48.4 vs 63.6 ± 68.5 mg of tramadol with P value of <0.001) and PACU discharge times (18.1 ± 5.4 vs 11.7 ± 4.3 hours with P value of <0.001) were significantly less in the opioid-free group.

CONCLUSIONS

Opioid-free anesthesia is a safer and better form of anesthesia in obese patients undergoing laparoscopic urological procedures as there is a lower requirement of postoperative analgesia.

Time course of psychomotor recovery after intravenous dexmedetomidine infusion as a part of balanced anaesthetic technique: A randomised, double-blind study

BACKGROUND AND AIMS

Dexmedetomidine is a drug that is being widely used as an adjuvant to anaesthesia because of its unique pharmacodynamic and pharmacokinetic properties. We aimed to assess the recovery of psychomotor function from balanced anaesthesia including intravenous dexmedetomidine infusion as adjunct.

METHODS

Ninety American Society of Anesthesiologists I and II patients were randomised to group D (n = 45), to receive 1 μg/kg of dexmedetomidine loading dose over 10 min, with maintenance infusion of 0.5 μg/kg/h, and group S (n = 45), to receive an equal volume of 0.9% normal saline. Objective parameters were recovery of psychomotor function assessed by Trieger dot test (TDT), digit symbol substitution test (DSST) and intraoperative opioid requirement. the total fentanyl used intraoperatively in the two groups. Statistical analysis was performed using unpaired Student's t-test, Chi-squareor Fisher's exact test.

RESULTS

Psychomotor recovery assessed by TDT showed statistically significant early recovery in group D compared with group S. This was seen in the maximum distance of dots missed at 30 min, 60 min, 90 min and 120 min as well as in the average distance of dots missed at identical time points. Similarly, DSST revealed early recovery at 30 min (12.4 ± 5.3 vs. 10.4 ± 3.9 P = 0.04) postoperative interval but not at other time intervals. There was significant decrease in the intraoperative opioid requirement in group D compared with group S.

CONCLUSION

The addition of dexmedetomidine to balanced anaesthetic technique significantly hastened the psychomotor recovery compared with placebo.

Psychomotor recovery of dexmedetomidine compared with propofol after sedation during spinal anesthesia: A randomized control trial

Background and Aims:

Early psychomotor recovery is an essential part of day care surgery which depends on brain integration of motor and sensory co-ordination. Even though dexmedetomidine is commonly used for day care procedures, the recovery profile was not studied. Hence, this study was designed to evaluate the psychomotor recovery of sedation with dexmedetomidine during spinal anesthesia.

Material and Methods:

Sixty-six patients were included. Group D received dexmedetomidine 0.5 μg/kg (loading dose) followed by 0.2–1 μg/kg/hour. Group P received propofol infusion of 25–100 μg/kg/minute. Psychomotor recovery was assessed by finger-tapping, manual dexterity, visual spatial memory capacity, and pen and paper tests. Psychomotor tasks were given to the patients postoperatively at every 30 minutes for 2 hours followed by every hour up to 4 hours after surgery. Distribution of patients, age, weight, duration of surgery, and the level of sensory blockade was compared using independent t-test. Student's t-test has been used to find the significance of parameters such as heart rate, mean arterial pressure, oxygen saturation (SpO₂), psychomotor recovery between two groups. P < 0.05 was considered as significant.

Results:

The motor recovery using finger tapping test was faster in Group D than Group P (73.94 ± 42.13 vs 101.21 ± 37.98 minutes, P–value = 0.007). Motor recovery using peg board test was faster in Group P than Group D (82.12 ± 40.37 vs 99.39 ± 43.08 minutes, P–value = 0.098). Visual spatial capacity memory test and pen and paper test were unaffected.

Conclusions:

We conclude that patients who received dexmedetomidine showed earlier recovery with finger tapping test. Hence, we suggest to use dexmedetomidine for complete psychomotor recovery and fast-track discharging of the patient after spinal anesthesia.

Analysis of postoperative cognitive dysfunction and influencing factors of dexmedetomidine anesthesia in elderly patients with colorectal cancer

Effect of dexmedetomidine-assisted general anesthesia on early postoperative cognitive dysfunctions in elderly patients with colorectal cancer was explored. In total, 140 patients with radical colorectal cancer under general anesthesia from March 2012 to June 2015 were enrolled in the Guizhou Provincial People's Hospital, including 80 patients in the dexmedetomidine group and 60 patients in the saline group. Surgery conditions were recorded, and the incidence of postoperative cognitive dysfunction (POCD) and cognitive function score (MMSE score) were compared between the two groups. Serum levels of S-100β protein (S-100β) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. The anesthesia time and intraoperative blood loss in the experiment group were significantly lower than those in the control group (P<0.05). The MMSE scores of the two groups on the 1st and 3rd day after surgery were lower than those before surgery (P<0.05). The incidence rates of the experiment group were significantly lower than that of the control group (P<0.05). The levels of serum IL-6 and S-100β were increased on the 1st and 3rd day after surgery compared with those before surgery (P<0.05). The levels of serum IL-6 and S-100β in the control group were significantly higher than those in the experiment group on the 1st and 3rd day after surgery (P<0.05). Age, duration of anesthesia, intraoperative blood loss, expression of IL-6 and S-100β were the influencing factors of POCD. Age ≥70 years, anesthesia duration ≥3 h, intraoperative blood loss ≥350 ml, and high expression of IL-6 and S-100β was an important factor related to the occurrence (P<0.05). Dexmedetomidine can significantly improve postoperative cognitive dysfunction in elderly patients with colorectal cancer, and the occurrence of cognitive dysfunction can be affected by age, duration of anesthesia, intraoperative blood loss and the high expression of IL-6 and S-100β.

Clinical Pharmacokinetics and Pharmacodynamics of Propofol

Propofol is an intravenous hypnotic drug that is used for induction and maintenance of sedation and general anaesthesia. It exerts its effects through potentiation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) at the GABAA receptor, and has gained widespread use due to its favourable drug effect profile. The main adverse effects are disturbances in cardiopulmonary physiology. Due to its narrow therapeutic margin, propofol should only be administered by practitioners trained and experienced in providing general anaesthesia. Many pharmacokinetic (PK) and pharmacodynamic (PD) models for propofol exist. Some are used to inform drug dosing guidelines, and some are also implemented in so-called target-controlled infusion devices, to calculate the infusion rates required for user-defined target plasma or effect-site concentrations. Most of the models were designed for use in a specific and well-defined patient category. However, models applicable in a more general population have recently been developed and published. The most recent example is the general purpose propofol model developed by Eleveld and colleagues. Retrospective predictive performance evaluations show that this model performs as well as, or even better than, PK models developed for specific populations, such as adults, children or the obese; however, prospective evaluation of the model is still required. Propofol undergoes extensive PK and PD interactions with both other hypnotic drugs and opioids. PD interactions are the most clinically significant, and, with other hypnotics, tend to be additive, whereas interactions with opioids tend to be highly synergistic. Response surface modelling provides a tool to gain understanding and explore these complex interactions. Visual displays illustrating the effect of these interactions in real time can aid clinicians in optimal drug dosing while minimizing adverse effects. In this review, we provide an overview of the PK and PD of propofol in order to refresh readers' knowledge of its clinical applications, while discussing the main avenues of research where significant recent advances have been made.

Perineural vs. intravenous dexmedetomidine as an adjunct to bupivacaine in ultrasound guided fascia iliaca compartment block for femur surgeries: A randomised control trial

BACKGROUND AND AIMS

Perineural and intravenous dexmedetomidine as a local anaesthetic adjunct has not been compared previously in fascia iliaca compartment block (FICB). The aim of this study was to compare the efficacy and side effect profile of dexmedetomidine as an adjunct to bupivacaine in single dose FICB for femur surgeries in two different routes i.e., perineural and intravenous route.

METHODS

Eighty American Society of Anesthesiologists physical status 1, 2 or 3 patients posted for femur surgeries were randomised to receive ultrasound guided FICB. Intravenous group(ID) received 40 mL of 0.25% bupivacaine with 2 mL of 0.9% saline for FICB along with 1 μg/kg dexmedetomidine intravenous infusion over 30 min as loading dose followed by 0.5 μg/kg/h as maintenance dose till the end of surgery. Perineural group (LD) received 40 mL of 0.25% bupivacaine with 2 mL of 1 μg/kg dexmedetomidine for FICB. M ean duration of postoperative analgesia and 24 h postoperative morphine consumption as primary and secondary outcome respectively, has been compared.

RESULTS

The duration of postoperative analgesia was 8 h 36 min ± 1 h 36 min and 10 h 42 min ± 1 h 36 min for the ID and LD groups, respectively (P = 0.001). A 24 h postoperative morphine consumption in Group ID was 19.7 ± 1.9 mg compared to 17.5 ± 2.2 mg in LD groups (P = 0.001).

CONCLUSION

Perineural dexmedetomidine effectively prolongs the USG guided FICB analgesic duration and reduces the 24 h postoperative morphine consumption when compared to intravenous dexmedetomidine as a local anaesthetic adjuvant for femur surgeries.

Alpha-2 adrenergic agonists for the prevention of cardiac complications among adults undergoing surgery

BACKGROUND

The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may help prevent postoperative cardiac complications.

OBJECTIVES

To determine the efficacy and safety of α-2 adrenergic agonists for reducing mortality and cardiac complications in adults undergoing cardiac surgery and non-cardiac surgery.

SEARCH METHODS

We searched CENTRAL (2017, Issue 4), MEDLINE (1950 to April Week 4, 2017), Embase (1980 to May 2017), the Science Citation Index, clinical trial registries, and reference lists of included articles.

SELECTION CRITERIA

We included randomized controlled trials that compared α-2 adrenergic agonists (i.e. clonidine, dexmedetomidine or mivazerol) against placebo or non-α-2 adrenergic agonists. Included trials had to evaluate the efficacy and safety of α-2 adrenergic agonists for preventing perioperative mortality or cardiac complications (or both), or measure one or more relevant outcomes (i.e. death, myocardial infarction, heart failure, acute stroke, supraventricular tachyarrhythmia and myocardial ischaemia).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials. We evaluated included studies using the Cochrane 'Risk of bias' tool, and the quality of the evidence underlying pooled treatment effects using GRADE methodology. Given the clinical heterogeneity between cardiac and non-cardiac surgery, we analysed these subgroups separately. We expressed treatment effects as pooled risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included 47 trials with 17,039 participants. Of these studies, 24 trials only included participants undergoing cardiac surgery, 23 only included participants undergoing non-cardiac surgery and eight only included participants undergoing vascular surgery. The α-2 adrenergic agonist studied was clonidine in 21 trials, dexmedetomidine in 24 trials and mivazerol in two trials.In non-cardiac surgery, there was high quality evidence that α-2 adrenergic agonists led to a similar risk of all-cause mortality compared with control groups (1.3% with α-2 adrenergic agonists versus 1.7% with control; RR 0.80, 95% CI 0.61 to 1.04; participants = 14,081; studies = 16). Additionally, the risk of cardiac mortality was similar between treatment groups (0.8% with α-2 adrenergic agonists versus 1.0% with control; RR 0.86, 95% CI 0.60 to 1.23; participants = 12,525; studies = 5, high quality evidence). The risk of myocardial infarction was probably similar between treatment groups (RR 0.94, 95% CI 0.69 to 1.27; participants = 13,907; studies = 12, moderate quality evidence). There was no associated effect on the risk of stroke (RR 0.93, 95% CI 0.55 to 1.56; participants = 11,542; studies = 7; high quality evidence). Conversely, α-2 adrenergic agonists probably increase the risks of clinically significant bradycardia (RR 1.59, 95% CI 1.18 to 2.13; participants = 14,035; studies = 16) and hypotension (RR 1.24, 95% CI 1.03 to 1.48; participants = 13,738; studies = 15), based on moderate quality evidence.There was insufficient evidence to determine the effect of α-2 adrenergic agonists on all-cause mortality in cardiac surgery (RR 0.52, 95% CI 0.26 to 1.04; participants = 1947; studies = 16) and myocardial infarction (RR 1.01, 95% CI 0.43 to 2.40; participants = 782; studies = 8), based on moderate quality evidence. There was one cardiac death in the clonidine arm of a study of 22 participants. Based on very limited data, α-2 adrenergic agonists may have reduced the risk of stroke (RR 0.37, 95% CI 0.15 to 0.93; participants = 1175; studies = 7; outcome events = 18; low quality evidence). Conversely, α-2 adrenergic agonists increased the risk of bradycardia from 6.4% to 12.0% (RR 1.88, 95% CI 1.35 to 2.62; participants = 1477; studies = 10; moderate quality evidence), but their effect on hypotension was uncertain (RR 1.19, 95% CI 0.87 to 1.64; participants = 1413; studies = 9; low quality evidence).These results were qualitatively unchanged in subgroup analyses and sensitivity analyses.

AUTHORS' CONCLUSIONS

Our review concludes that prophylactic α-2 adrenergic agonists generally do not prevent perioperative death or major cardiac complications. For non-cardiac surgery, there is moderate-to-high quality evidence that these agents do not prevent death, myocardial infarction or stroke. Conversely, there is moderate quality evidence that these agents have important adverse effects, namely increased risks of hypotension and bradycardia. For cardiac surgery, there is moderate quality evidence that α-2 adrenergic agonists have no effect on the risk of mortality or myocardial infarction, and that they increase the risk of bradycardia. The quality of evidence was inadequate to draw conclusions regarding the effects of alpha-2 agonists on stroke or hypotension during cardiac surgery.

Postoperative benefits of dexmedetomidine combined with flurbiprofen axetil after thyroid surgery

The present study determined the effect of dexmedetomidine (Dex) combined with flurbiprofen axetil (FA) on analgesia, immune response, and preservation of cognitive function in patients subjected to general anesthesia. We recruited 100 patients with thyroid surgery and randomly divided them into four groups: Dex (D), FA (F), Dex combined with FA (DF), and saline control (C). The extubation and recovery times for Groups D and DF were significantly longer than for Groups F and C. After extubation, the heart rate and mean arterial pressure for Groups F, D, and DF were significantly lower than for Group C, and data for Group DF was significantly lower than for Group F. The visual analog scale and Riker sedation agitation scores were significantly lower in Group DF than for the other three groups. T- and B-lymphocytes were significantly higher in Group DF than in the other three groups. Compared with Groups F and C, the levels of TNF-α and IL-6 in Group DF were significantly reduced, while IL-2 markedly increased. The combined use of Dex and FA significantly improved pain after general anesthesia thyroid surgery, reduced restlessness and postoperative cognitive dysfunction, enhanced immune function, and promoted wound repair.

The Effect of Perineural Administration of Dexmedetomidine on Narcotic Consumption and Pain Intensity in Patients Undergoing Femoral Shaft Fracture Surgery; A Randomized Single-Blind Clinical Trial

Dexmedetomidine is a selective α-2 adrenoceptor agonist with anxiolytic, sedative, and analgesic properties that prolongs analgesia and decreases opioid-related side effects when used in neuraxial and perineural areas as a local anesthetics adjuvant. The current study was designed to evaluate the effects of a single perineural administration of dexmedetomidine without local anesthetics on narcotic consumption and pain intensity in patients with femoral shaft fractures undergoing surgery. This prospective randomized single-blind clinical trial was conducted in patients undergoing femoral fracture shaft surgery. Based on block permuted randomization, the patients were randomly divided into intervention and control groups. The intervention group received 100µg dexmedetomidine, for a femoral nerve block without any local anesthetics. Total intraoperative opioid consumption, postoperative opioid consumption, visual analogue score (VAS) for pain, and hemodynamic parameters were recorded and compared. Finally the data from 60 patients with a mean age of 30.4±12.3 were analyzed (90% male). There were no significant differences between the baseline characteristics of the two groups (p>0.05). The mean total consumption of narcotics was reduced during induction and maintenance of anesthesia in the intervention group (p<0.05). The amount of postoperative narcotics required showed a significant difference in the intervention group compared with the control group (p<0.05). It is likely that perineural administration of dexmedetomidine significantly not only reduced intra and postoperative narcotic requirement but also decreased postoperative pain intensity in patients undergoing femoral shaft surgery. Femoral blockade by dexmedetomidine can provide excellent analgesia while minimizing the side-effects of opioids.

Feasibility of dexmedetomidine as sole analgesic agent during robotic urological surgery: A pilot study

BACKGROUND AND AIMS

Opioid-free anesthesia decreases postoperative nausea and vomiting, emergence agitation, prolonged sedation, ileus, and urinary retention. The feasibility of the use of dexmedetomidine as sole analgesic agent has been shown in patients undergoing bariatric and gynecological laparoscopic surgery. We explored its use for robotic urological surgery.

MATERIAL AND METHODS

Thirty patients were randomized to receive either dexmedetomidine (Group D) or fentanyl (Group F) along with total intravenous anesthesia with propofol. The hemodynamic parameters and number of doses of rescue analgesics used intraoperatively and postoperatively were noted. Recovery parameters at the end of surgery were also recorded.

RESULTS

The dose of intraoperative rescue fentanyl was not significantly different between groups (P = 0.13). The hemodynamic profile of patients in the two groups was comparable except the heart rate was significantly more in Group D after intubation and at 60 min. The mean arterial pressure was significantly lower after the initial loading dose of study drug in Group D. The recovery profiles were not significantly different between groups.

CONCLUSION

The study reveals that dexmedetomidine has equal analgesic efficacy as fentanyl for intraoperative use and can be used as the sole analgesic agent in patients undergoing robotic urological surgery.

Effects of Dexmedetomidine on Intraoperative Hemodynamics and Propofol Requirement in Patients Undergoing Laparoscopic Cholecystectomy

Background

Despite multiple benefits, laparoscopic surgery always poses anesthetic challenge due to significant alteration of hemodynamics. Various pharmacological agents have been used for the same with variable response. Dexmedetomidine, in addition to sympatholytic effect, diminishes intraoperative requirement of anesthetics including propofol. The present study was conducted to evaluate the effects of intravenous dexmedetomidine on intraoperative hemodynamics and propofol requirement using bispectral index (BIS) in laparoscopic cholecystectomy.

Methods

Forty patients undergoing laparoscopic cholecystectomy were randomly allocated to receive either dexmedetomidine (Group A; n = 20) or normal saline (Group B; n = 20). In Group A, dexmedetomidine was loaded (1 μg/kg) before anesthesia induction and infused (0.6 μg/kg/h) during surgery. Anesthesia was induced with propofol, and maintenance infusion rate was adjusted to a BIS of 55-60 in both groups. Mean arterial pressure (MAP) and heart rate (HR) were recorded at baseline and at various time points from loading of drugs to just after tracheal extubation. All infusions were stopped with removal of scope from abdominal cavity. Recovery time (time from end of all infusions to BIS = 80) and extubation time (time from end of all infusions to extubation) were noted.

Results

After intubation, MAP and HR values in Group A were significantly lower than Group B at various time points of study. To achieve similar BIS values, significantly low doses of propofol were required in Group A during induction and intraoperatively. Doses were reduced by 36% and 31%, respectively. Mean recovery time and mean extubation time in Group A were also significantly less.

Conclusion

During propofol-based anesthesia for laparoscopic cholecystectomy, dexmedetomidine provides stable intraoperative hemodynamics and reduces propofol requirement for induction as well as maintenance, without compromising recovery profile.

Dexmedetomidine in Attenuation of Haemodynamic Response and Dose Sparing Effect on Opioid and Anaesthetic Agents in Patients undergoing Laparoscopic Cholecystectomy- A Randomized Study

INTRODUCTION

Perioperative procedures are stressful and lead to haemodynamic instability with potentially devastating consequences. Dexmedetomidine is found to have many of the desired characteristics that are required in perioperative period.

AIM

To evaluate the ability of pre and intraoperative dexmedetomidine to attenuate stress induced haemodynamic responses, quantifying the anaesthetic agents sparing as well as its cost-effectiveness in patients undergoing laparoscopic cholecystectomy.

MATERIALS AND METHODS

The present single blind randomized study was conducted with 120 ASA I and II consented patients who underwent laparoscopic cholecystectomy. Patients were randomly divided into 2 groups (i.e., group D and group N). Prior to induction, group D received 1 μg/kg of Dexmedetomidine and group N received Normal saline infusion over 20 minutes. Group D also received maintenance Dexmedetomidine intraoperatively. Bispectral index and minimum alveolar concentration monitoring was done in both the groups. Haemodynamic parameters were noted till 100 minutes post laryngoscopy. Opioid and anaesthetic agent consumptions were also noted and cost analysis was done. Medcalc-Version 12.5.0.0 software was used for statistics and p <0.05 was considered significant.

RESULTS

Dexmedetomidine attenuated the stress induced haemodynamics responses and produced stable, relatively non fluctuating haemodynamics throughout. The Minimum Alveolar Concentration (MAC) requirement and the consumptions of Fentanyl and Isoflurane were significantly less in the Dexmedetomidine group (p<0.0001). However, despite anaesthetic dose sparing effect the anaesthetic technique was not cost-effective.

CONCLUSION

Dexmedetomidine is effective in attenuating haemodynamic responses in laparoscopic surgery and having dose sparing effect on Fentanyl, Propofol and Isoflurane. However, overall this technique is not cost-effective.

Effects of dexmedetomidine on perioperative monitoring parameters and recovery in patients undergoing laparoscopic cholecystectomy

BACKGROUND

Dexmedetomidine, an α2 agonist, when used as an adjuvant in general anesthesia attenuates stress response to various noxious stimuli, maintains perioperative hemodynamic stability and provides sedation without adversely affecting recovery in postoperative period.

MATERIALS AND METHODS

Sixty patients were randomly divided into two groups of 30 each. In Group A, dexmedetomidine was given intravenously as loading dose of 1 μg/kg over 10 min, and normal saline was given in Group B patients. After induction with propofol, in Group A, dexmedetomidine was given as infusion at a dose of 0.2-0.8 μg/kg/h. Sevoflurane was used as inhalation agent in both groups. Perioperative monitoring parameters were recorded. Postoperative sedation and recovery were assessed.

STATISTICAL ANALYSIS USED

Demographic data were analyzed using Pearson's Chi-square test. Changes in the heart rate (HR), systolic blood pressure (BP) and diastolic BP were analyzed using unpaired t-test and Mann-Whitney rank sum test was used to calculate "P" value wherever (Shapiro-Wilk)/normality test gave ambiguous results.

RESULTS

Dexmedetomidine significantly attenuates stress response at intubation with lesser increase in HR (86.00 ± 5.16 vs. 102.97 ± 7.07/min.), mean BP (95.78 ± 5.35 vs. 110.18 ± 5.35) as compared to the control group (P < 0.05). After pneumoperitoneum, HR was 85.07 ± 6.23 versus 107.10 ± 4.98, mean BP was 98.98 ± 10.16 versus 118.54 ± 6.27 (P < 0.05). Thus maintains intraoperative hemodynamic stability. Postoperatively, the test group showed no statistically significant difference in the extubation time (7.00 ± 0.58 vs. 6.74 ± 0.73) and response to oral commands (8.78 ± 0.72 vs. 8.66 ± 0.73) (P > 0.05).

CONCLUSION

Dexmedetomidine attenuates various stress responses during surgery and maintains the hemodynamic stability when used as an adjuvant in general anesthesia and dexmedetomidine does not delay recovery.

Intranasal Dexmedetomidine as a Sedative Premedication for Patients Undergoing Suspension Laryngoscopy: A Randomized Double-Blind Study

Background

Intranasal dexmedetomidine, a well-tolerated and convenient treatment option, has been shown to induce a favorable perioperative anxiolysis in children. We investigate intranasal dexmedetomidine as a sedative premedication for anesthesia recovery in an adult population.

Methods

A prospective randomized controlled trial; 81 adult patients scheduled for elective suspension laryngoscopy received intranasal dexmedetomidine (1 μg∙kg^–1) or a placebo 45–60 min before anesthetic induction. Extubation time was used as the primary outcome measure. Secondary variables included the levels of sedation (Observer’s Assessment of Alertness/Sedation scale, OAA/S) and anxiety (4-point anxiety score), anesthetic and analgesic requirements, hemodynamic fluctuations, and anesthesia recovery as well as side effects.

Results

The levels of sedation and anxiety differed significantly between the two groups at anesthesia pre-induction (p < 0.001 and = 0.001, respectively). Repeated-measure general linear model determined no significant interaction effect between group and time on the targeted concentration of propofol (F = 1.635, p = 0.200), but a significant main effect of group existed (F = 6.880, p = 0.010). A moderate but significant decrease in the heart rate was recorded in the dexmedetomidine group at pre-induction. Episodes of tachycardia and hypertension after tracheal intubation and extubation were more frequent in the placebo group.

Conclusions

Intranasal dexmedetomidine as a sedative premedication induced a favorable perioperative anxiolysis without prolongation in anesthesia recovery; the hemodynamic effect was modest.

Trial Registration

ClinicalTrials.gov NCT 02108171

Perioperative dexmedetomidine for acute pain after abdominal surgery in adults

BACKGROUND

Acute postoperative pain is still an issue in patients undergoing abdominal surgery. Postoperative pain and side effects of analgesic treatment, in particular those of opioids, need to be minimized. Opioid-sparing analgesics, possibly including dexmedetomidine, seem a promising avenue by which to improve postoperative outcomes.

OBJECTIVES

Our primary aim was to determine the analgesic efficacy and opioid-sparing effect of perioperative dexmedetomidine for acute pain after abdominal surgery in adults.Secondary aims were to establish effects of dexmedetomidine on postoperative nausea and vomiting (PONV), gastrointestinal function and mobilization, together with the side effect profile of dexmedetomidine.

SEARCH METHODS

We searched the following databases: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Institute for Scientific Information (ISI), Web of Science and Cumulative Index to Nursing and Allied Health Literature (CINAHL), and reference lists of articles to May 2014. We searched the Science Citation Index, ClinicalTrials.gov and Current Controlled Trials, and we contacted pharmaceutical companies to identify unpublished and ongoing studies. We applied no language restrictions. We reran the search in May 2015 and found nine studies of interest. We will deal with the studies of interest when we update the review.

SELECTION CRITERIA

We included randomized, controlled trials of perioperative dexmedetomidine versus placebo or other drug during abdominal surgery in adults. Trials included one of the following outcomes: amount of 'rescue' opioid, postoperative pain, time to 'rescue' analgesia, participants requiring 'rescue' analgesia, postoperative sedation, PONV, time to first passage of flatus and stool or time to first out-of-bed mobilization.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts for eligibility. We retrieved full trial reports if necessary, and we extracted relevant data from the included studies using a data collection form and assessed risk of bias. We resolved disagreements by discussion with the third review author. We sought additional information of relevance for risk of bias assessment or extraction of data by contacting study authors or, if necessary, co-authors from present or former studies.

MAIN RESULTS

Our systematic review included seven studies with a total of 492 participants. We included 422 participants in our analysis. Thirteen studies are awaiting classification. For the comparison dexmedetomidine versus placebo (six studies, 402 participants), most studies found a reduction in 'rescue' opioid consumption in the first 24 hours after surgery, together with in general no clinically important differences in postoperative pain (visual analogue scale (VAS) 0 to 100 mm, where 0 = no pain and 100 = worst imaginable pain) in the first 24 hours after surgery - except for one study (80 participants) with a reduction in VAS pain at two hours after surgery in favour of dexmedetomidine, with a mean difference of -30.00 mm (95% confidence interval (CI) -38.25 to -21.75). As the result of substantial heterogeneity, pooling of data in statistical meta-analyses was not appropriate. The quality of evidence was very low for our primary outcomes because of imprecision of results and risk of bias. Regarding our secondary aims, evidence was too scant in general to allow robust conclusions, or the estimates too imprecise or of poor methodological quality. Regarding adverse effects, low quality data (one study, 80 participants) suggest that the proportion of participants with hypotension requiring intervention was slightly higher in the high-dose dexmedetomidine group with a risk ratio of 2.50 (95% CI 0.94 to 6.66), but lower doses of dexmedetomidine led to no differences compared with control. Evidence for the comparison dexmedetomidine versus fentanyl was insufficient to permit robust conclusions (one study, 20 participants).

AUTHORS' CONCLUSIONS

Dexmedetomidine, when administered perioperatively for acute pain after abdominal surgery in adults, seemed to have some opioid-sparing effect together with in general no important differences in postoperative pain when compared with placebo. However the quality of the evidence was very low as the result of imprecision, methodological limitations and substantial heterogeneity among the seven included studies. The clinical importance for patients is uncertain, in as much as the influence of dexmedetomidine on patient-important outcomes such as gastrointestinal function, mobilization and adverse effects could not be satisfactorily determined. All included studies were relatively small, and publication bias could not be ruled out. Applicability of evidence was limited to middle-aged participants who were relatively free of co-morbidity and were undergoing elective abdominal surgery. A potential bias was a considerable quantity of unobtainable data from studies with mixed surgery. To detect and investigate patient-important outcomes, larger studies with longer periods of follow-up are needed.

The Effects of Dexmedetomidine on Myocardial Function Assessed by Tissue Doppler Echocardiography During General Anesthesia in Patients With Diastolic Dysfunction: A CONSORT-Prospective, Randomized, Controlled Trial

Dexmedetomidine is a commonly used sedative and adjuvant agent to general anesthesia. The present was designed to evaluate the effects of dexmedetomidine on myocardial function by using tissue Doppler echocardiography during general anesthesia in patients with diastolic dysfunction.Forty patients undergoing orthostatic surgery with ejection fraction preserved diastolic dysfunction grade 2 or 3 were randomly allocated to the Control and Dex group (n = 20, each). In the Dex group, dexmedetomidine was given as an initial loading dose of 1.0 μg/kg over 10 minutes followed by a maintenance dose of 0.5 μg/kg/h. The ratio of peak early diastolic transmitral or transtricuspid inflow velocity to early diastolic mitral or tricuspid annular velocity (LV or RV E/e') and left or right ventricular myocardial performance index (LV or RV MPI) were measured at before and after the administration dexmedetomidine or saline.The Dex group showed significant decrease of heart rate (P = 0.038), and increase of mean blood pressure (P < 0.001), LV E/e' (P = 0.025), and LV MPI (P < 0.001) compared to those of the Control group on a linear mixed model analysis. Also, the Dex group showed significant increase of RV E/e' (P < 0.001) and RV MPI (P = 0.028) compared to those of the Control group.Intraoperative dexmedetomidine administration during general anesthesia was appeared to deteriorate biventricular function in patients with diastolic dysfunction. We suggest careful consideration and a need for reducing dosage when administrating dexmedetomidine in patients with diastolic dysfunction.

Effect of dexmedetomidine bolus dose on isoflurane consumption in surgical patients under general anesthesia

Background and Objective:

Various adjuvants have been introduced to decrease the dose of volatile agents and their side effects. Dexmedetomidine a potent alpha-2 adrenoreceptor agonist is one such agent. Our objective is to assess the effect of preanesthetic dexmedetomidine on isoflurane consumption and its effect on intraoperative hemodynamic stability and recovery profile.

Setting and Design:

This prospective, randomized controlled, double-blind study was done in a tertiary care hospital.

Materials and Methods:

One hundred patients were randomly allocated into two groups. Group 1 received saline infusion and Group 2 received dexmedetomidine infusion in a dose of 1 μg/kg over 10 min given 15 min before induction. Vital parameters and bispectral index (BIS) values were noted throughout the surgery. Patients were induced and intubated as per the standard protocol and maintained with N₂O: O₂ = 1:1 mixture at 2 L/min and isoflurane concentration adjusted to achieve BIS values of 45–60. Demographic profile, hemodynamic variables, total isoflurane consumption, and recovery profile data were collected.

Statistics:

Independent t-test and Mann–Whitney U-test were used to compare the average anesthetic consumption, hemodynamics, and recovery profile between two groups.

Results:

End-tidal concentration and total isoflurane consumption in Group 2 were 0.56 ± 0.11 and 10.69 ± 3.01 mL, respectively, with P < 0.001 which was statistically significant compared to Group 1 which were 0.76 ± 0.14 and 13.76 ± 3.84 mL. Postintubation and intraoperative mean arterial pressure values were significantly lower in dexmedetomidine group with P < 0.001.

Conclusion:

Preanesthetic bolus dose of dexmedetomidine is a useful adjuvant to reduce isoflurane consumption.

Effects of dexmedetomidine on smooth emergence from anaesthesia in elderly patients undergoing orthopaedic surgery

BACKGROUND

Intraoperative dexmedetomidine may decrease postoperative emergence agitation in elderly patients due to its sedative effect. In this study, we evaluated the effect of adjuvant dexmedetomidine on smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

METHODS

A total 115 patients (ASA I-II, aged over 65 years) were randomly allocated into four groups. Anaesthesia was maintained with either sevoflurane or total intravenous anaesthesia (TIVA) comprising propofol and remifentanil. Patients were also administered either dexmedetomidine (0.4 μg kg(-1) hr(-1); SD and TD) intraoperatively or normal saline (SN or TN) as a control. The bispectral index (BIS) score was maintained from 40-60 intraoperatively. All anaesthetics and dexmedetomidine were discontinued at surgical conclusion, and the recovery times (durations to a BIS = 60, 70, and 80; eye opening; and extubation) were measured. The mean arterial pressure, heart rate, Ricker's agitation-sedation scale (RSAS), visual analogue scale (VAS) for pain, and incidences of emergence agitation and postoperative nausea and vomiting (PONV) were measured in the recovery room.

RESULTS

Dexmedetomidine significantly decreased the RSAS score in the SD and TD groups, and a calm state postoperatively occurred more frequently in these groups than in the control groups. The heart rate and incidence of emergence agitation were lower in the dexmedetomidine groups. Recovery time was higher in the SD group than in the SN group, and no significant differences occurred between the TN and TD groups. The VAS score was lower in the SD group than in the SN group, and the PONV did not differ regardless of the use of dexmedetomidine.

CONCLUSIONS

Dexmedetomidine may be an effective intraoperative adjuvant for a reducing emergence agitation and smooth emergence from anaesthesia after orthopaedic surgery in elderly patients.

TRIAL REGISTRATION

Current Controlled Trials NCT01851005 .

Effects of dexmedetomidine and clonidine as propofol adjuvants on intra-operative hemodynamics and recovery profiles in patients undergoing laparoscopic cholecystectomy: A prospective randomized comparative study

Context:

Alpha-2 (α2) adrenergic receptor agonists, clonidine and dexmedetomidine, are widely used as adjuvants during anesthesia for analgesic, sedative, sympatholytic, and cardiovascular stabilizing effects.

Aims:

We compared effects of clonidine and dexmedetomidine (as propofol adjuvants) on intra-operative hemodynamics, recovery time, and postoperative cognitive function impairment.

Subjects and Methods:

Forty-five American Society of Anesthesiologists I and II patients, scheduled for laparoscopic cholecystectomy were divided into three groups (n = 15). Group C patients received bolus of clonidine 3 μg/kg followed by a continuous infusion; Group D patients received dexemedetomidine 1 μg/kg and a continuous infusion; and Group P patients received a bolus of normal saline followed by an infusion. Intra-operative mean arterial pressure (MAP) and pulse rate (PR) were measured throughout the surgery. Bispectral index was maintained at 55 ± 5 by titrating propofol infusion rate. The time between the interruption of anesthesia and eye opening (recovery time) was measured. Cognitive function was assessed using short mental status questionnaire at 15, 30, 45, and 60 min postoperatively.

Results:

The sympathetic response to laryngoscopy and extubation on MAP and PR were significantly reduced with the use of clonidine and dexmedetomidine (P < 0.05). The recovery was delayed (P < 0.05) with both the drug combinations and it was more pronounced with dexmedetomidine (P < 0.05). Dexmedetomidine group showed cognitive impairment in a postoperative period lasting up to an hour.

Conclusions:

When co-administered with propofol, both clonidine, and dexmedetomidine attenuate sympathetic response to laryngoscopy and extubation but cause delay in the recovery from anesthesia. Dexmedetomidine causes impairment of postoperative cognitive functions.

Doxapram hastens the recovery following total intravenous anesthesia with dexmedetomidine, propofol and remifentanil

Dexmedetomidine is a suitable sedative for awake fiberoptic intubation in patients with obstructive sleep apnea (OSA). However, previous studies have shown that dexmedetomidine delays recovery from propofol-remifentanil anesthesia. This study aimed to determine whether doxapram may hasten the recovery following dexmedotomidine-propofol-remifentanil anesthesia. Sixty patients scheduled for uvulopalatopharyngoplasty with total intravenous anesthesia were randomized to two groups according to the medicine given at the end of surgery. These were the doxapram (1 mg/kg) and control (normal saline) groups (n=30 per group). The primary outcome was the time to eye opening on verbal command. The time to return to spontaneous breathing, to hand squeezing in response to verbal command, to extubation of the trachea, and the heart rate (HR), bispectral index (BIS) values, respiratory rate (RR) and pulse oximetry values were also recorded and compared. The time to return to spontaneous breathing (5.2±2.9 vs. 11.7±3.4 min, P<0.001), eye opening (9.3±4.7 vs. 15.9±6.3 min, P<0.001), hand squeeze to command (11.8±6.5 vs. 17.6±7.7 min, P=0.0026) and extubation (14.2±7.8 vs. 19.2±9.6 min, P=0.0308) were significantly shorter in the doxapram group compared with the control group. BIS scores (at 3–14 min), RR (at 4–10 min) and HR (at 2–13 min) were significantly higher in the doxapram group compared with those in the control group (P<0.05). Doxapram hastens the recovery from dexmedetomidine-propofol-remifentanil anesthesia in patients undergoing uvulopalatopharyngoplasty, and may benefit patients with OSA.

Dexmedetomidine decreases the requirement of ketamine and propofol during burns debridement and dressings

Background and Aims:

Dexmedetomidine (Dex), a highly selective α₂-adrenoreceptor agonist, is used for sedation management in various clinical settings and shows anaesthetic-sparing effect. Our aim was to study the effects of Dex on requirements of propofol, ketamine, and intraoperative haemodynamic variations during burns debridement and dressing changes, and compare its effectiveness and safety with combination of ketamine and propofol.

Methods:

Sixty adult patients posted for elective debridement and dressing were included in the study. Thirty patients received Dex (intramuscular)(IM) 1 μg/kg, 1 h before shifting to the operation theatre while the other thirty did not. Anaesthesia was induced with propofol and ketamine followed by adjusted infusion to achieve a Ramsay Sedation Scale score (RSS) of six in all patients. Intraoperatively haemodynamic parameters were recorded at regular intervals of 5, 15, 30, 45, and 60 min. The mean data between the groups were compared by unpaired t test and medians by Mann-Whitney U test. Within group analysis was performed by using repeated measures ANOVA. P < 0.05 was considered significant.

Results:

The dose requirement of ketamine and propofol in Dex group was significantly lower when compared to control group (100.5 ± 17.58 mg vs. 231.5 ± 60.39 mg (P < 0.0001) and 127.7 ± 15.47 mg vs. 254 ± 59.22 mg (P < 0.0001) respectively). Additionally, recovery time was lower in the Dex group as compared to the control group, 9.57 ± 1.50 min vs. 11.53 ± 2.56 min (P = 0.0006). Haemodynamic variations were also significantly lower in the Dex group as compared to the control group.

Conclusion:

Dexmedetomidine (1 μg/kg IM) reduced the requirement of propofol and ketamine, with more stable intraoperative haemodynamics.

Opioid-free total intravenous anesthesia with propofol, dexmedetomidine and lidocaine infusions for laparoscopic cholecystectomy: a prospective, randomized, double-blinded study

BACKGROUND AND OBJECTIVES

Intraoperative use of opioids may be associated with postoperative hyperalgesia and increased analgesic consumption. Side effects due to perioperative use of opioids, such as postoperative nausea and vomiting may delay discharge. We hypothesized that total intravenous anesthesia consisting of lidocaine and dexmedetomidine as an opioid substitute may be an alternative technique for laparoscopic cholecystectomy and would be associated with lower fentanyl requirements in the postoperative period and less incidence of postoperative nausea and vomiting.

METHODS

80 Anesthesiologists I-II adults were scheduled for elective laparoscopic cholecystectomy. Patients were randomly allocated into two groups to have either opioid-free anesthesia with dexmedetomidine, lidocaine, and propofol infusions (Group DL) or opioid-based anesthesia with remifentanil, and propofol infusions (Group RF). All patients received a standard multimodal analgesia regimen. A patient controlled analgesia device was set to deliver IV fentanyl for 6h after surgery. The primary outcome variable was postoperative fentanyl consumption.

RESULTS

Fentanyl consumption at postoperative 2nd hour was statistically significantly less in Group DL, compared with Group RF, which were 75 ± 59 μg and 120 ± 94 μg respectively, while it was comparable at postoperative 6th hour. During anesthesia, there were more hypotensive events in Group RF, while there were more hypertensive events in Group DL, which were both statistically significant. Despite higher recovery times, Group DL had significantly lower pain scores, rescue analgesic and ondansetron need.

CONCLUSION

Opioid-free anesthesia with dexmedetomidine, lidocaine and propofol infusions may be an alternative technique for laparoscopic cholecystectomy especially in patients with high risk for postoperative nausea and vomiting.

Effect of dexmedetomidine on sevoflurane requirements and emergence agitation in children undergoing ambulatory surgery

PURPOSE

Dexmedetomidine, a potent selective α2-adrenergic agonist, produces sedation and analgesia. This study was conducted to assess the effect of dexmedetomidine infusion on sevoflurane requirements, recovery profiles, and emergence agitation in children undergoing ambulatory surgery.

MATERIALS AND METHODS

Forty children undergoing ambulatory hernioplasty or orchiopexy were randomized into two groups. The dexmedetomidine group (Group D, n=20) received dexmedetomidine 1 μg/kg, followed by 0.1 μg/kg/h until the end of surgery, whereas the saline group (Group S, n=20) received volume-matched normal saline. Sevoflurane was used for induction and maintenance of anesthesia and caudal block was performed in all children. End-tidal sevoflurane concentration (ET-sevo), the incidence of emergence agitation, pain scores, and sedation scores were recorded. Hemodynamic changes and other adverse effects were assessed in the perioperative period.

RESULTS

ET-sevo of Group D was significantly reduced in 23.8-67% compared to Group S during surgery. The incidence of emergence agitation was lower in Group D than in Group S (5% vs. 55%, p=0.001). Postoperative pain was comparable, and discharge time was not different between the groups. Mean arterial pressure and heart rate were significantly lower in Group D during surgery.

CONCLUSION

Intraoperative infusion of dexmedetomidine reduced sevoflurane requirements and decreased emergence agitation without delaying discharge in children undergoing ambulatory surgery. However, caution should be taken in regard to bradycardia and hypotension.

Dexmedetomidine prevents alterations of intestinal microcirculation that are induced by surgical stress and pain in a novel rat model

BACKGROUND

Anesthesia can become inadequate inadvertently or by misjudgment during surgery or emergence, and the surgical stress and pain stimulation will increase without adequate treatment. Overt stimulation may activate the sympathetic nervous system, increase the blood level of catecholamines, and lead to splanchnic arterial vasoconstriction.

METHODS

We divided 30 male Wistar rats into the following 3 groups: control, surgical stress and pain (SSP), and surgical stress and pain + dexmedetomidine (SSP + Dex). The rats received midline laparotomy to exteriorize a segment of terminal ileum for microcirculation examination by a full-field laser perfusion imager and sidestream dark-field video microscope on mucosa, muscle, and Peyer patch. The inspired concentration of isoflurane was decreased from 1.2% to 0.7% in SSP and SSP + Dex groups. In the SSP + Dex group, the rats received an initial loading dose of dexmedetomidine (0.5 μg/kg) and a maintenance infusion (0.5 μg · kg(-1) · h(-1)).

RESULTS

Dexmedetomidine prevented surgical stress and pain-related tachycardia and hypertension, and it attenuated the reduction of the microcirculatory blood flow intensity in intestinal mucosa (1100 ± 185 perfusion units [PU] vs 800 ± 105 PU, P = 0.001) and muscle (993 ± 208 PU vs 713 ± 92 PU, P < 0.001). Dexmedetomidine restored perfused small vessel density in intestinal mucosa and muscle.

CONCLUSIONS

We established a promising rat model to investigate the effect of surgical stress and pain stimulation on the intestinal microcirculation during light anesthesia. Using this rat model, we found that dexmedetomidine can normalize global hemodynamics and prevent the alteration of intestinal microcirculation.

The effect of dexmedetomidine on the adjuvant propofol requirement and intraoperative hemodynamics during remifentanil-based anesthesia

BACKGROUND

The effects of dexmedetomidine on the propofol-sparing effect and intraoperative hemodynamics during remifentanil-based propofol-supplemented anesthesia have not been well investigated.

METHODS

Twenty patients undergoing breast surgery were randomly allocated to receive dexmedetomidine (group DEX) or placebo (group C). In the DEX group, dexmedetomidine was loaded (1 µg/kg) before anesthesia induction and was infused (0.6 µg/kg/h) during surgery. Anesthesia was induced with a target-controlled infusion (TCI) of propofol (effect site concentration, Ce; 3 µg/ml) and remifentanil (plasma concentration, Cp, 10 ng/ml). The Ce of TCI-propofol was adjusted to a bispectral index of 45-55, and Cp of TCI-remifentanil was fixed at 10 ng/ml in both groups. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at baseline (T-control), after the loading of study drugs (T-loading), 3 min after anesthesia induction (T-induction), tracheal intubation (T-trachea), incision (T-incision), 30 min after incision (T-incision30), and at tracheal extubation (T-extubation). MAP% and HR% (MAP and HR vs. T-control) were determined and the propofol infusion rate was calculated.

RESULTS

The propofol infusion rate was significantly lower in the DEX group than in group C (63.9 ± 16.2 vs. 96.4 ± 10.0 µg/kg/min, respectively; P < 0.001). The changes in MAP% at T-induction, T-trachea and T-incision in group DEX (-10.0 ± 3.9%, -9.4 ± 4.6% and -11.2 ± 6.3%, respectively) were significantly less than those in group C (-27.6 ± 13.9%, -21.7 ± 17.1%, and -25.1 ± 14.1%; P < 0.05, respectively).

CONCLUSIONS

Dexmedetomidine reduced the propofol requirement for remifentanil-based anesthesia while producing more stable intraoperative hemodynamics.