Low-dose intramuscular dexmedetomidine as premedication: a randomized controlled trial

Anaesthetic Approach to Enhanced Recovery after Surgery for Kidney Transplantation: A Narrative Review

Enhanced recovery after surgery (ERAS) protocols are designed to reduce medical complications, the length of hospital stays (LoS), and healthcare costs. ERAS is considered safe and effective for kidney transplant (KTx) surgery. KTx recipients are often frail with multiple comorbidities. As these patients follow an extensive diagnostic pathway preoperatively, the ERAS protocol can ideally be implemented at this stage. Small singular changes in a long perioperative pathway can result in significant positive outcomes. We have investigated the current evidence for an ERAS pathway related to anaesthetic considerations in renal transplant surgery for adult recipients.

Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has sedative, anxiolytic, analgesic, sympatholytic, and opioid-sparing properties and induces a unique sedative response which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Recent studies indicate several emerging clinical applications via different routes. We review recent data on dexmedetomidine studies, particularly exploring the varying routes of administration, experimental implications, clinical effects, and comparative advantages over other drugs. A search was conducted on the PubMed and Web of Science libraries for recent studies using different combinations of the words “dexmedetomidine”, “route of administration”, and pharmacological effect. The current routes, pharmacological effects, and application categories of dexmedetomidine are presented. It functions by stimulating pre- and post-synaptic α2-adrenoreceptors within the central nervous system, leading to hyperpolarization of noradrenergic neurons, induction of an inhibitory feedback loop, and reduction of norepinephrine secretion, causing a sympatholytic effect, in addition to its anti-inflammation, sleep induction, bowel recovery, and sore throat reduction effects. Compared with similar α2-adrenoceptor agonists, dexmedetomidine has both pharmacodynamics advantage of a significantly greater α2:α1-adrenoceptor affinity ratio and a pharmacokinetic advantage of having a significantly shorter elimination half-life. In its clinical application, dexmedetomidine has been reported to present a significant number of benefits including safe sedation for various surgical interventions, improvement of intraoperative and postoperative analgesia, sedation for compromised airways without respiratory depression, nephroprotection and stability of hypotensive hemodynamics, reduction of postoperative nausea and vomiting and postoperative shivering incidence, and decrease of intraoperative blood loss. Although the clinical application of dexmedetomidine is promising, it is still limited and further research is required to enhance understanding of its pharmacological properties, patient selection, dosage, and adverse effects.

Effect of multimodal preemptive analgesia on postoperative gastrointestinal function and clinical outcome in patients undergoing laparoscopic colorectal surgery

OBJECTIVE

This study aimed to investigate the effects of multimodal preemptive analgesia on postoperative gastrointestinal function and clinical outcomes in patients undergoing laparoscopic colorectal surgery.

METHODS

This prospective study included a total of 108 patients undergoing elective laparoscopic colorectal surgery from June 2019 to June 2020. The patients were divided into the control group and the study group according to the random number table method. Patients in the study group were given flurbiprofen axetil and oxycodone before skin incision combined with bilateral transverse abdominis plane block (TAPB) before anaesthesia induction. In the control group, patients were given sufentanil and flurbiprofen axetil combined with bilateral TAPB in postanaesthesia care unit (PACU). The incidence of postoperative gastrointestinal dysfunction (POGD), I-FEED score, inflammatory factor levels, rehabilitation indicators, postoperative pain assessment and other organ complications were observed and compared between the two groups.

RESULTS

The incidence of POGD in the study group was lower compared to the control group, and the difference was statistically significant (P < .05). The study group had lower total and mean scores of I-FEED at 24, 48, 72 and 96 hours after surgery; however, the differences were not statistically significant (P > .05). On the first and third day after operation, Lipopolysaccharide (LPS), C-reactive protein (CRP), Tumour necrosis factor (TNF-α) and Interleukins6 (IL-6) levels of the study group decreased significantly (P < .05). The reduction in inflammation factor levels from 1d to 3d was significantly greater than that of the control group (P < .05).

CONCLUSION

The strategy of multimodal preemptive analgesia can effectively prevent the onset of POGD and may accelerate rehabilitation. In short, multimodal preemptive analgesia provides a novel prevention strategy for patients undergoing laparoscopic colorectal surgery.

Dexmedetomidine as an Analgesic Agent with Neuroprotective Properties: Experimental and Clinical Aspects

Dexmedetomidine (Dexdor or Precedex®) is considered as a sedative agent which is widely used as an adjuvant in general anesthesia and critical care practice. There is extensive evidence indicating its neuroprotective properties especially in various ischemic and hemorrhagic brain injury models of animals. Clinical trials have shown that dexmedetomidine (DEX) can improve the outcome of intensive care unit (ICU) patients. Also, DEX is appropriate as a non-opioid analgesic therapy whenever minimizing opioid-related side effects is necessary. The present article reviews the recent advances in the use of DEX as a neuroprotective agent in both animal and human studies including newest findings about the mechanism of the drug as well as analgesic efficacy of this drug at all perioperative stages. In spite of the beneficial effects of the drug on the nervous system, there are potential adverse effects, such as hypotension and bradycardia, which can be treated pharmacologically and must be taken into consideration by clinicians.

Pharmacokinetics and Pharmacodynamics of 3 Doses of Oral-Mucosal Dexmedetomidine Gel for Sedative Premedication in Women Undergoing Modified Radical Mastectomy for Breast Cancer

BACKGROUND

Buccal dexmedetomidine (DEX) produces adequate preoperative sedation and anxiolysis when used as a premedication. Formulating the drug as a gel decreases oral losses and improves the absorption of buccal DEX. We compared pharmacokinetic and pharmacodynamic properties of 3 doses of buccal DEX gel formulated in our pharmaceutical laboratory for sedative premedication in women undergoing modified radical mastectomy for breast cancer.

METHODS

Thirty-six patients enrolled in 3 groups (n = 12) to receive buccal DEX gel 30 minutes before surgery at 0.5 µg/kg (DEX 0.5 group), 0.75 µg/kg (DEX 0.75 group), or 1 µg/kg (DEX 1 group). Assessments included plasma concentrations of DEX, and pharmacokinetic variables calculated with noncompartmental methods, sedative, hemodynamic and analgesic effects, and adverse effects.

RESULTS

The median time to reach peak serum concentration of DEX (Tmax) was significantly shorter in patients who received 1 µg/kg (60 minutes) compared with those who received 0.5 µg/kg (120 minutes; P = .003) and 0.75 µg/kg (120 minutes; P = .004). The median (first quartile-third quartile) peak concentration of DEX (maximum plasma concentration [Cmax]) in plasma was 0.35 ng/mL (0.31-0.49), 0.37 ng/mL (0.34-0.40), and 0.54 ng/mL (0.45-0.61) in DEX 0.5, DEX 0.75, and DEX 1 groups (P = .082). The 3 doses did not produce preoperative sedation. The 1 µg/kg buccal DEX gel produced early postoperative sedation and lower intraoperative and postoperative heart rate values. Postoperative analgesia was evident in the 3 doses in a dose-dependent manner with no adverse effects.

CONCLUSIONS

Provided that it is administered 60-120 minutes before surgery, sublingual administration of DEX formulated as an oral-mucosal gel may provide a safe and practical means of sedative premedication in adults.

Effects of dexmedetomidine as an adjuvant in thoracic paravertebral block on EC50 of propofol for successful laryngeal mask insertion: a randomized controlled trial

Background

Dexmedetomidine as an adjuvant can improve the duration and the quality of thoracic paravertebral block (TPVB); however, its quantitative effect on propofol infusion is unclear. This study aimed to investigate the effect of dexmedetomidine as an adjuvant in TPVB on the medium effective concentration (EC50) of propofol for successful laryngeal mask insertion.

Methods

Sixty breast cancer patients who underwent elective modified radical mastectomy were enrolled and randomized at a 1:1 ratio into control group (Group C, n=30) or dexmedetomidine group (Group D, n=30). Ultrasound-guided T3 paravertebral block was performed before induction of anesthesia. In Group C, 0.5% ropivacaine 0.3 mL/kg was injected into T3 paravertebral space, while subjects in Group D received 0.5% ropivacaine 0.3 mL/kg with dexmedetomidine (1 µg/kg). Propofol target-controlled infusion (TCI) was performed, with an initial target effect-site concentration of 5 µg/mL determined for both groups. The laryngeal mask was inserted once the effect chamber achieved the target concentration. Subsequent target concentrations were adjusted by Dixon up-down sequential method, where dose modifications were performed by 0.5 mg/mL intervals, based on the success of the laryngeal mask insertion. Probit analysis was used to determine the propofol EC50. Mean arterial pressure (MAP), heart rate (HR), bispectral index (BIS) and application of atropine or ephedrine was recorded. Participants, TPVB giver, and data recorder were blinded to group assignment.

Results

Propofol EC50 for successful laryngeal mask insertion were statistically significant, with 5.256 µg/mL (95% CI: 4.833, 5.738 µg/mL) in Group C and 3.172 µg/mL (95% CI: 2.701, 3.621 µg/mL) in Group D. Both groups displayed significantly lower MAP and HR, post propofol TCI (P<0.05). However, subjects in Group D exhibited lower MAP and HR levels compared to patients in Group C (P<0.05). Application of atropine (0% vs. 10%) and ephedrine (20.0% vs. 13.3%) were not significantly different between two groups.

Conclusions

Dexmedetomidine, administered as an adjuvant in TPVB, can reduce the TCI concentration of propofol for successful laryngeal mask placement in females. The target concentration of propofol requires adjustment and close monitoring of hemodynamic changes, post induction is warranted.

Trial registration

Chinese Clinical Trial Registry ChiCTR1800016614.

Dexmedetomidine Improves Cardiovascular and Ventilatory Outcomes in Critically Ill Patients: Basic and Clinical Approaches

Dexmedetomidine (DEX) is a highly selective α2-adrenergic agonist with sedative and analgesic properties, with minimal respiratory effects. It is used as a sedative in the intensive care unit and the operating room. The opioid-sparing effect and the absence of respiratory effects make dexmedetomidine an attractive adjuvant drug for anesthesia in obese patients who are at an increased risk for postoperative respiratory complications. The pharmacodynamic effects on the cardiovascular system are known; however the mechanisms that induce cardioprotection are still under study. Regarding the pharmacokinetics properties, this drug is extensively metabolized in the liver by the uridine diphosphate glucuronosyltransferases. It has a relatively high hepatic extraction ratio, and therefore, its metabolism is dependent on liver blood flow. This review shows, from a basic clinical approach, the evidence supporting the use of dexmedetomidine in different settings, from its use in animal models of ischemia-reperfusion, and cardioprotective signaling pathways. In addition, pharmacokinetics and pharmacodynamics studies in obese subjects and the management of patients subjected to mechanical ventilation are described. Moreover, the clinical efficacy of delirium incidence in patients with indication of non-invasive ventilation is shown. Finally, the available evidence from DEX is described by a group of Chilean pharmacologists and clinicians who have worked for more than 10 years on DEX.

Attenuation of haemodynamic responses to laryngoscopy and endotracheal intubation with dexmedetomidine: A comparison between intravenous and intranasal route

Background and Aims:

Haemodynamic changes during endotracheal intubation are major concerns in general anaesthesia This study compared the efficacy of intranasal and intravenous dexmedetomidine (DEX) to attenuate the stress response of laryngoscopy and endotracheal intubation.

Methods:

In this prospective, randomised, double-blinded study, 70 adults were divided into two groups [Group D_IV(n=35) and Group D_IN(n=35)]. D_IV group received intravenous dexmedetomidine (DEX) infusion (0.5 μg/kg) over 40 min and D_IN group received intranasal dexmedetomidine (1 μg/kg) 40 min before induction. The primary objective was the comparison the mean arterial pressure (MAP) between two groups from 40 min before induction at every 10 min intervals till induction of anaesthesia, at the time of intubation, thereafter every 1 min interval till 5 min, at 7 min and 10 min after intubation. The secondary outcomes were comparison of heart rate, systolic and diastolic blood pressure along with sedation and other adverse effects. Statistical analysis was with Statistica 6.0 and Graph Pad prism version 5.

Results:

In both the groups, all the haemodynamic parameters were maintained within (20% of baseline values) throughout the study period. There was no statistically significant difference in MAP between two groups (P>0.05). Preoperative sedation score was significantly higher in the D_IV group than the D_IN group (P = 0.014).

Conclusion:

Like IV DEX, intranasal DEX can also attenuate the haemodynamic stress responses of laryngoscopy and endotracheal intubation without significant differences in MAP between two groups.

Dexmedetomidine in perioperative acute pain management: a non-opioid adjuvant analgesic

Many nociceptive, inflammatory, and neuropathic pathways contribute to perioperative pain. Although opioids have long been a mainstay for perioperative analgesia, other non-opioid therapies, and dexmedetomidine, in particular, have been increasingly used as part of a multimodal analgesic regimen to provide improved pain control while minimizing opioid-related side effects. This article reviews the evidence supporting the preoperative, intraoperative, and postoperative efficacy of dexmedetomidine as an adjuvant, and the efficacy of intravenous, spinal canal, and nerve block analgesia with dexmedetomidine for perioperative acute pain treatment. While there have not been any large-scale clinical trials conducted, the current body of evidence suggests that dexmedetomidine is suitable for use as an adjuvant analgesic at all perioperative stages. However, there are potential adverse effects, such as hypotension and bradycardia, which must be taken into consideration by clinicians.

Impact of Dexmedetomidine on Pediatric Agitation in the Postanesthesia Care Unit

PURPOSE

This study aims to investigate the impacts of dexmedetomidine (DEX) on agitation in the postanesthesia care unit (PACU) for pediatric patients undergoing tonsillectomy.

DESIGN

Eighty-two pediatric patients with elective tonsillectomy were randomly divided into the DEX group (group D) and the control group (group C). All patients' surgery in the two study groups were completed under tracheal cannula-based general anesthesia. Group D was infused 0.2 mcg/kg/hour DEX. The operation time, extubation time, PACU time, number of cases with nausea and vomiting, hemodynamic changes, and doses of rescue fentanyl, as well as every 10-minute observational pain scoring, and emergence agitation score in PACU, of the two groups were recorded.

METHODS

Chi-square and Fischer exact tests were applied for categorical variables.

FINDINGS

The maximum observational pain scoring and emergence agitation score of group D at 0, 10, and 20 minutes in PACU were significantly lower than group C (P < .01); the rescue doses of fentanyl and incidence of severe agitation in PACU in group D were significantly reduced than group C (P < .01). Group D showed significantly less cases with nausea and vomiting than group C (P < .05).

CONCLUSIONS

Low-dose DEX could significantly reduce the delirium and agitation in the PACU stage of pediatric tonsillectomy, and there were no untoward hemodynamic events in this study of 80 patients.

Premedication with midazolam in intellectually disabled dental patients: intramuscular or oral administration? A retrospective study

Background

The use of midazolam for dental care in patients with intellectual disability is poorly documented. The purpose of this study was to determine which method of premedication is more effective for these patients, 0.15 mg/kg of intramuscular midazolam or 0.3 mg/kg of oral midazolam.

Material and Methods

This study was designed and implemented as a non-randomized retrospective study. The study population was composed of patients with intellectual disability who required dental treatment under ambulatory general anesthesia from August 2009 through April 2013. Patients were administered 0.15 mg/kg of midazolam intramuscularly (Group IM) or 0.3 mg/kg orally (Group PO). The predictor variable was the method of midazolam administration. The outcome variables measured were Observer’s Assessment of Alertness/ Sedation (OAA/S) Scale scores, the level of cooperation when entering the operation room and for venous cannulation, post-anesthetic agitation and recovery time.

Results

Midazolam was administered intramuscularly in 23 patients and orally in 21 patients. More patients were successfully sedated with no resistance behavior during venous cannulation in Group PO than in Group IM (p=0.034). There were no differences in demographic data and other variables between the groups.

Conclusions

The results of this study suggest that oral premedication with 0.3 mg/kg of midazolam is more effective than 0.15 mg/kg of midazolam administered intramuscularly, in terms of patient resistance to venous cannulation. If both oral and intramuscular routes of midazolam are acceptable in intellectually disabled patients, the oral route is recommended.

Key words:Premedication, midazolam, intellectual disability.

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

Target-Controlled Infusion of Propofol in Training Anesthesiology Residents in Colonoscopy Sedation: A Prospective Randomized Crossover Trial

BACKGROUND

Propofol is widely used in sedation for colonoscopy, but its adverse effects on cardiovascular and respiratory systems are still concerning. The present study investigated whether target controlled infusion (TCI) of propofol could provide a better sedation quality than manually controlled infusion (MCI) in training inexperienced anesthesiology residents.

MATERIAL/METHODS

Eighteen training residents were allocated into 2 groups receiving TCI and MCI training in their first month in the endoscopy center, while receiving MCI and TCI training instead in their second month. The last 2 patients at the end of each month were included to analyze the sedation quality of TCI and MCI techniques by comparing satisfaction of endoscopist and patients based on the visual analogue scale (VAS). Heart rate (HR), mean blood pressure (MAP), SpO2, and recovery time were also compared as the secondary outcomes.

RESULTS

The demographic data were similarly distributed among the TCI and MCI patients. Endoscopist's satisfaction score in the TCI group was significantly higher than in the MCI group, 81.3±7.2 versus 74.2±9.5 (P=0.003), but the patients' satisfaction score was similar between the 2 groups. More stable hemodynamic status was obtained in the TCI group, manifested as higher lowest MAP and lower highest MAP than in the MCI group. Lowest SpO2 in the TCI group was significantly higher than in the MCI group. Patients in the TCI group recovered earlier than in the MCI group.

CONCLUSIONS

TCI is a more effective and safer technique for anesthesiology residents in sedation for colonoscopy.

Comparative Evaluation of Remifentanil and Dexmedetomidine in General Anesthesia for Cesarean Delivery

Background

Use of remifentanil and dexmedetomidine in general anesthesia for cesarean section have been described. This study was designed to evaluate the effects of remifentanil and dexmedetomidine on maternal hemodynamics and bispectral index, and neonatal outcomes in elective caesarean delivery.

Material/Methods

Forty-four women undergoing elective cesarean delivery with ASA I or II and term or near-term singleton pregnancies were randomly assigned to receive remifentanil at a loading dose of 2 μg/kg over 10 min followed by a continuous infusion of 2 μg/kg/h until about 6 min before fetal delivery (Group REM), or dexmedetomidine at a loading dose of 0.4 μg/kg over 10 min followed by a continuous infusion of 0.4 μg/kg/h until about 6 min before fetal delivery (Group DEX). Maternal hemodynamics and BIS values were recorded. Neonatal effects were assessed using Apgar scores and umbilical cord blood gas analysis.

Results

Mean arterial pressure (MAP) increased after intubation in both groups, and the change magnitude of the MAP was higher in Group DEX (P<0.05). Patients in Group DEX had a lower BIS value at recovery and consumed less propofol during surgery (P<0.05). The incidences of neonatal resuscitation at 1 min were 81.8% in Group REM and 54.5% in Group DEX (P=0.052). There was no significant difference in either group in Apgar scores at 1 and 5 min and umbilical cord blood gas values.

Conclusions

Both remifentanil and dexmedetomidine are effective to blunt hemodynamic responses to intubation and also seem safe for neonates at the administrated doses, but remifentanil still has the potential to cause neonatal transient respiratory depression.

Propofol requirement for induction of unconsciousness is reduced in patients with Parkinson's disease: a case control study

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease, but whether the neurodegenerative process influences the pharmacodynamics of propofol remains unclear. We aimed to evaluate the effect of PD on pharmacodynamics of propofol. A total of 31 PD patients undergoing surgical treatment (PD group) and 31 pair-controlled non-PD patients undergoing intracranial surgery (NPD group) were recruited to investigate the propofol requirement for unconsciousness induction. Unconsciousness was induced in all patients with target-controlled infusion of propofol. The propofol concentration at which unconsciousness was induced was compared between the two groups. EC₅₀ and EC₉₅ were calculated as well. Demographic data, bispectral index, and hemodynamic values were comparable between PD and NPD groups. The mean target concentration of propofol when unconsciousness was achieved was 2.32 ± 0.38 μg/mL in PD group, which was significantly lower than that in NPD group (2.90 ± 0.35 μg/mL). The EC₅₀ was 2.05 μg/mL (95% CI: 1.85–2.19 μg/mL) in PD group, much lower than the 2.72 μg/mL (95% CI: 2.53–2.88 μg/mL) in NPD group. In conclusion, the effective propofol concentration needed for induction of unconsciousness in 50% of patients is reduced in PD patients. (This trial is registered with NCT01998204.)

Comparison of Dexmedetomidine versus Propofol for Sedation after Uvulopalatopharyngoplasty

Background

Adequate sedation is important in the post-anesthesia care unit (PACU) following uvulopalatopharyngoplasty (UPPP) to ensure patient comfort and decrease the duration of mechanical ventilation (MV), PACU stay, and bleeding. This study aimed to compare dexmedetomidine and propofol as sedatives after UPPP in the PACU.

Material/Methods

We randomized 124 mechanically ventilated adults following UPPP who were managed in the PACU of the General Hospital of the Shenyang Military Region between January 2014 and June 2014, to receive either dexmedetomidine or propofol. The patients in the propofol group received an infusion of propofol (3 mg/kg/h) titrated up to 6 mg/kg/h to attain a Ramsay sedation score ≥4. The dexmedetomidine group patients received 1.0 μg/kg of dexmedetomidine over a period of 10 minutes and then 0.5 to 1.0 μg/kg/h infusion to maintain a Ramsay sedation score ≥4.

Results

Bispectral index (BIS) values were significantly lower in the dexmedetomidine group than in the propofol group at Ramsay sedation scores of 4 and 5. The mean times to spontaneous breathing, waking, and extubation were shorter in the dexmedetomidine group. Tramadol requirement was significantly reduced in the dexmedetomidine group (P<0.05). Incidence of cough during the extubation process in the propofol group was higher than in the dexmedetomidine group. After extubation, Bruggemann comfort scale (BCS) and Rass agitation scores (RASS) were decreased in the dexmedetomidine-sedated patients.

Conclusions

Dexmedetomidine provides safe and effective sedation for post-UPPP surgical patients and significantly reduces the use of analgesics, with minimal adverse effects.