The correlation of heart rate between natural sleep and dexmedetomidine sedation

Insight into Cardioprotective Effects and Mechanisms of Dexmedetomidine

PURPOSE

Cardiovascular disease remains the leading cause of death worldwide. Dexmedetomidine is a highly selective α2 adrenergic receptor agonist with sedative, analgesic, anxiolytic, and sympatholytic properties, and several studies have shown its possible protective effects in cardiac injury. The aim of this review is to further elucidate the underlying cardioprotective mechanisms of dexmedetomidine, thus suggesting its potential in the clinical management of cardiac injury.

RESULTS AND CONCLUSION

Our review summarizes the findings related to the involvement of dexmedetomidine in cardiac injury and discusses the results in the light of different mechanisms. We found that numerous mechanisms may contribute to the cardioprotective effects of dexmedetomidine, including the regulation of programmed cell death, autophagy and fibrosis, alleviation of inflammatory response, endothelial dysfunction and microcirculatory derangements, improvement of mitochondrial dysregulation, hemodynamics, and arrhythmias. Dexmedetomidine may play a promising and beneficial role in the treatment of cardiovascular disease.

The feasibility of dexmedetomidine-led anesthesia maintenance strategy during major abdominal surgery

Background

Dexmedetomidine is known for its selective action on α2-adrenoceptor sites and is recognized for its neuroprotective capabilities. It can improve postoperative cognitive function. Commonly used anesthetics, such as sevoflurane and propofol, have been reported to affect postoperative cognitive function. Therefore, it could be valuable to explore dexmedetomidine-led anesthesia strategy. This study was designed to assess the performance, safety, and effective infusion rate in anesthesia maintenance, to explore a feasible dexmedetomidine-led anesthesia maintenance protocol, and to provide a foundation for potential combined anesthesia.

Methods

Thirty patients aged 18-60 years, classified as ASA I or II, undergoing abdominal surgery were involved. The anesthesia maintenance was achieved with dexmedetomidine, remifentanil and rocuronium. Dixon up-and-down sequential methodology was utilized to ascertain the ED50 of dexmedetomidine for maintaining Patient State Index (PSI) 25-40 (depth of stage III anesthesia). Intraoperative HR, BP and depth of anesthesia were monitored and controlled. The wake-up time from anesthesia, the incidence of intraoperative awareness and postoperative delirium, and the patients' satisfaction were assessed.

Results

The results indicated that dexmedetomidine-led anesthesia could maintain the depth of stage III anesthesia during abdominal surgery. The ED50 and ED95 of dexmedetomidine infusion rates during anesthesia maintenance were 2.298 μg/kg·h (95%CI: 2.190-2.404 μg/kg·h) and 3.765 μg/kg·h (95%CI: 3.550-4.050 μg/kg·h). Continuous infusion of dexmedetomidine and 0.1-0.3 μg/kg·min remifentanil could maintain PSI 25-40, and provide appropriate anesthesia depth for abdominal surgery. Perioperative bradycardia and hypertension could be rapidly corrected with atropine and nitroglycerin. The median wake-up time after anesthesia was 4.8 min, the perioperative maximum HR had significant correlation with wake-up time and intraoperative dexmedetomidine dose. No intraoperative awareness and postoperative delirium occurred; the patients were satisfied with dexmedetomidine-led anesthesia.

Conclusions

dexmedetomidine-led strategy could maintain stable depth of anesthesia throughout surgery, and the ED50 of dexmedetomidine infusion rates was 2.298 μg/kg·h. Intraoperative HR, BP and depth of anesthesia require monitoring, the bradycardia and hypertension could be rapidly corrected.

Effects of short-term preoperative intranasal dexmedetomidine plus conventional treatment on delirium following cardiac surgery in patients with sleep disorders

STUDY OBJECTIVES

To assess whether preoperative dexmedetomidine (DEX) nasal drips combined with conventional treatment could mitigate the occurrence of postoperative delirium (POD).

DESIGN

A prospective randomised controlled study.

SETTING

The cardiac surgery intensive care unit (CSICU) and patient hospitalisation ward at a university hospital.

PARTICIPANTS

A total of 100 patients (aged ≥60 years) undergoing cardiac surgery at a university hospital between 7 January 2022, and 30 November 2022 met the eligibility criteria and were included in the study.

INTERVENTIONS

Patients with sleep disorders (Pittsburgh Sleep Quality Index ≥8) were divided into two groups: Group A (the placebo group, n=50), receiving a short-term preoperative placebo combined with conventional treatment and Group B (the DEX group, n=50), receiving short-term preoperative DEX combined with conventional treatment.

MEASUREMENTS AND RESULTS

The Confusion Assessment Method for the ICU (CAM-ICU) was used for POD assessment in the CSICU, while the CAM was employed to assess delirium in the patient ward. Group B demonstrated a reduced incidence of POD compared to Group A (12% vs. 30%, odds ratio: 0.318, 95% confidence interval: 0.112-0.905, p=0.027).

CONCLUSION

The combined treatment involving DEX demonstrated a decreased incidence of POD in elderly individuals with sleep disorders undergoing cardiac surgery compared to the placebo combination treatment.

TRIAL REGISTRATION

URL: www.chictr.org.cn with registration number ChiCTR 2100043968, registered on 06/03/2021.

Dexmedetomidine Pretreatment Confers Myocardial Protection and Reduces Mechanical Ventilation Duration for Patients Undergoing Cardiac Valve Replacement under Cardiopulmonary Bypass

PURPOSE

The study aims to assess the effects of dexmedetomidine (Dex) pretreatment on patients during cardiac valve replacement under cardiopulmonary bypass.

METHODS

For patients in the Dex group (n = 52), 0.5 μg/kg Dex was given before anesthesia induction, followed by 0.5 μg/kg/h pumping injection before aortic occlusion. For patients in the control group (n = 52), 0.125 ml/kg normal saline was given instead of Dex.

RESULTS

The patients in the Dex group had longer time to first dose of rescue propofol than the control group (P = 0.003). The Dex group required less total dosage of propofol than the control group (P = 0.0001). The levels of cardiac troponin I (cTnI), creatine kinase isoenzyme MB (CK-MB), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) were lower in the Dex group than the control group at T4, 8 h after the operation (T5), and 24 h after the operation (T6) (P <0.01). The Dex group required less time for mechanical ventilation than the control group (P = 0.003).

CONCLUSION

The study suggests that 0.50 µg/kg Dex pretreatment could reduce propofol use and the duration of mechanical ventilation, and confer myocardial protection without increased adverse events during cardiac valve replacement.

Comparison of Caudal Block and Dexmedetomidine Infusion in Pediatric Patients Undergoing Hypospadias Repair Surgery: A Prospective, Randomized, Double-blinded Clinical Study

Background

Many parents continue to reject caudal block since they worry about a rare neurological consequence that may happen. A parenteral surrogate is sought because it can induce recovery with features such as local analgesia.

Objectives

To compare the efficacy and safety of intravenous dexmedetomidine versus caudal and general anesthesia (GA) in children undergoing hypospadias surgery repair.

Methods

A randomized prospective study was conducted on 135 pediatric patients scheduled for hypospadias repair surgery in the hospital affiliated to Tanta University. The participants were divided into a control group (Group C) receiving GA, a caudal group receiving caudal block after GA, and a dexmedetomidine group (Group D) receiving intravenous dexmedetomidine after GA. The postoperative modified objective pain score (MOPS), the total pethidine received in the first 24 h postoperatively, and complications were recorded.

Results

The patients receiving GA required a significantly higher pethidine dose than the other two groups without a significant difference between caudal and dexmedetomidine. The patients receiving dexmedetomidine were extubated significantly later than patients in the other two groups. Regarding the MOPS score, there was a significant difference between Group C and the other two groups 30 minutes and one hour after operation regarding movements, posture, and agitation. Moreover, a significantly larger number of patients developed tachycardia in Group C compared to the other groups.

Conclusions

With the caudal block, the benefits of smooth emergency can be obtained by intravenous dexmedetomidine; however, it had less analgesic efficacy in the pediatric patients undergoing hypospadias repair surgery.

Patient Comfort During Postop Period in Breast Cancer Surgeries: A Randomized Controlled Trial Comparing Opioid and Opioid-Free Anesthesia

BACKGROUND

Anesthetic management practices have advanced to opioid-free anesthesia (OFA) often replacing opioids in oncologic surgeries. The study was conducted to find the quality of recovery (QoR) of patients undergoing breast cancer surgeries receiving OFA.

METHODS

A double-blinded, randomized controlled study was conducted with 60 patients randomized to group OFA and group OA (opioid anesthesia). Group OFA received one-time dosing of ketamine 0.3 mg/kg, lignocaine 1.5 mg/kg, and dexmedetomidine 1 mcg/kg. Group OA received fentanyl 2mcg/kg. Intraoperatively, Group OFA received dexmedetomidine 0.4 mcg/kg/h and the OA group received fentanyl 0.5 mcg/kg/h infusion. Bispectral index (BIS), hemodynamics, muscle relaxant administration, and sevoflurane concentration were noted. A modified QoR-40 score was used to assess the quality of recovery in the postoperative period.

RESULTS

A higher QoR-40 score was found in the OA group (median 182, IQR 178-186) compared to the OFA group (median 180, IQR 178-184). Out of the five components, the patient's emotional state was better in the group OA (39.9±2.77) than in the OFA group (37.9±2.77). The patient's physical comfort was found to be better in the group OFA (52.52±3.23) compared to group OA (50.93±3.23). Physical independence, psychological support, and pain were comparable between the two groups. Patients in group OFA received less sevoflurane, a muscle relaxant, and showed a mild reduction in heart rate and mean arterial pressure (MAP) when compared to group OA. The time taken to reach a Modified Aldrete score of 9 was high in OFA (11.47±2.16) and (9.17±1.09) when compared to group OA. No significant differences were noted with the visual analog score (VAS) score, Ramsay sedation score, and modified post-anesthesia discharge scoring system (PADSS) score.

CONCLUSION

We conclude that the quality of recovery of patients receiving opioid-free methods of anesthesia was not inferior to OA in patients undergoing breast cancer surgeries.

Could dexmedetomidine be repurposed as a glymphatic enhancer?

Cerebrospinal fluid (CSF) flows through the central nervous system (CNS) via the glymphatic pathway to clear the interstitium of metabolic waste. In preclinical studies, glymphatic fluid flow rate increases with low central noradrenergic tone and slow-wave activity during natural sleep and general anesthesia. By contrast, sleep deprivation reduces glymphatic clearance and leads to intracerebral accumulation of metabolic waste, suggesting an underlying mechanism linking sleep disturbances with neurodegenerative diseases. The selective α₂-adrenergic agonist dexmedetomidine is a sedative drug that induces slow waves in the electroencephalogram, suppresses central noradrenergic tone, and preserves glymphatic outflow. As recently developed dexmedetomidine formulations enable self-administration, we suggest that dexmedetomidine could serve as a sedative-hypnotic drug to enhance clearance of harmful waste from the brain of those vulnerable to neurodegeneration.

Dexmedetomidine and perioperative analgesia in children

Dexmedetomidine (DEX) is an anaesthetic agent that mimics natural deep sleep and produces minimal cardiorespiratory depression. As such, it is a very valuable option in the management of such a challenging population as paediatric patients. The main objective of this mini review was to evaluate the role of DEX as a perioperative analgesic in children receiving anaesthesia. We searched Google, Pubmed, Embase and the Cochrane Library for articles published between 2010 and 2021, and reviewed various of aspects of DEX, such as pharmacology, effectiveness, safety, and the most recent evidence on its clinical use as an analgesic in paediatric anaesthesia. We also include a cost estimate of perioperative analgesia with DEX.

Comparison of the Sedative and Analgesic Effects of Dexmedetomidine-Remifentanil and Dexmedetomidine-Sufentanil for Liposuction: A Prospective Single-Blind Randomized Controlled Study

BACKGROUND

Dexmedetomidine had sedative and analgesic effects and did not produce significant respiratory depression at therapeutic doses.

AIMS

To compare the sedative and analgesic effects and safety of dexmedetomidine combined with remifentanil or sufentanil in patients undergoing liposuction.

METHODS

A total of 100 subjects were randomized 1:1 to two groups: Group R and Group S. First, patients were administered midazolam 0.02 mg·kg^-1. Anesthesia was induced with an intravenous infusion of dexmedetomidine 1 µg kg^-1 (15 min) and remifentanil 0.1 µg kg^-1 min^-1 (Group R) or sufentanil 0.1 µg kg^-1h^-1 (Group S). Anesthesia was maintained with an intravenous infusion of dexmedetomidine 1.0 µg kg^-1h^-1, midazolam 0.015 mg kg^-1h^-1, remifentanil 0.1 µg kg^-1min^-1 (Group R), or sufentanil 0.1 µg kg^-1h^-1 (Group S). Hemodynamic and respiratory changes, modified OAA/S score and BIS values, postoperative Visual Analogue Scale pain scores, satisfaction of the patient and surgical team with the procedure, and adverse events and recovery time were recorded.

RESULTS

Group R received significantly less midazolam and midazolam per hour compared to Group S (Group R vs. Group S: 3.4 ± 1.7 mg vs. 5.1 ± 2.0 mg, P < 0.0001; 1.5 ± 0.7 mg/h vs. 1.9 ± 0.6 mg/h, P = 0.002). The incidence of physical or verbal expressions of pain at the start of surgery was significantly lower in Group R compared to Group S (2 [4.3%] vs. 12 [26.7%], P = 0.003). Patient satisfaction with the procedure was significantly higher in Group R compared to Group S (3.9 ± 0.3 vs. 3.1 ± 0.3, P < 0.0001).

CONCLUSION

Dexmedetomidine-remifentanil and dexmedetomidine-sufentanil were effective and safe sedative and analgesic agents for liposuction. Hemodynamic stability was maintained. Dexmedetomidine-remifentanil might be associated with improved analgesic effects compared to dexmedetomidine-sufentanil.

LEVEL OF EVIDENCE II

Evidence was obtained from at least one properly designed randomized controlled trial. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Anesthesia, Sedation, and Unplanned Extubation of Tracheal Intubation in Children with Severe Pneumonia

We randomly divided 200 children with severe pneumonia who met the indications for tracheal intubation into 2 groups in this prospective study. One group that received dexmedetomidine for sedation was recorded as the dexmedetomidine group (n = 100), and the group that received midazolam for sedation was recorded as the midazolam group (n = 100). We compared the anesthesia sedation scores, time to fall asleep, time to wake up from anesthesia, related hemodynamic parameters, and adverse reactions between the two groups of children. The failure mode and effect analysis method (FMEA) was also used to investigate the causes of unplanned extubation (UEX) of tracheal intubation in 32 children with severe pneumonia. Our conclusion is as follows: (1) Compared with midazolam, the comprehensive effect of dexmedetomidine on children with severe pneumonia undergoing tracheal intubation for anesthesia and sedation is better, it can effectively shorten the anesthesia induction time and the recovery time after stopping the drug, and there are few adverse reactions, which is worthy of application and promotion. (2) UEX is an important risk factor in the monitoring and nursing of children with severe pneumonia tracheal intubation, and the nursing method of PDCA cycle management is particularly important for them.

The Effect of Continuous Field Block through Intercostal Muscles after Atrial Septal Defect Closure via a Mini-Right Thoracotomy in Pediatric Patients

BACKGROUND

Postoperative pain management in thoracotomy patients often is difficult. Furthermore, pediatric patients present more challenges because of their inability to effectively communicate their pain intensity. The purpose of this study was to evaluate the use of continuous field block through intercostal muscles as postoperative pain management in pediatric thoracotomy.

METHODS

Between 2014 and 2018, 11 patients underwent an ASD closure using a cardiopulmonary bypass via a mini-right thoracotomy through the fourth intercostal space. At the time of chest closure, a single-shot field block via the fourth intercostal muscles was performed with levobupivacaine (0.6 mg/kg). The first five patients were only given the single-shot field block (Single group). The remaining six patients were given levobupivacaine continuously (0.1 mg/kg/hr) through an indwelling catheter until the chest tube removal (Continuous group). The groups' vital signs, total amounts of acetaminophen used, postoperative courses were compared.

RESULTS

Although the heart rate did not differ between the groups, the respiratory rate was significantly higher in the Single group versus the Continuous group at 16 and 32 hr post-surgery (35.6 ± 9.7/min vs. 18.5 ± 4.7/min; p=0.007, 43.0 ± 10.4 vs. 25.3 ± 3.1; p=0.042, respectively). The accumulated dosage of acetaminophen given by postoperative day 2 was significantly higher in the Single group versus the Continuous group (55.3 ± 22.1 mg/kg vs. 7.8 ± 17.4 mg/kg; p=0.012).

CONCLUSIONS

Continuous field block via intercostal muscles after ASD closure via a mini-right thoracotomy in children was effective to stabilize the vital signs and reduce the analgesic medication use.

The correlation between the STOP-Bang score and oxygen saturation during spinal anesthesia with dexmedetomidine sedation

BACKGROUND

The STOP-Bang questionnaire is a simple screening tool with high sensitivity for the detection of severe obstructive sleep apnea. Predicting airway obstruction would allow the safe management of sedative patients to prevent intraoperative hypoxia. This study was designed to check the correlation between the STOP-Bang score and oxygen saturation (SpO2) during sedation and confirm the availability of the STOP-Bang questionnaire as a preoperative exam for predicting the incidence of hypoxia in sedative patient management.

METHODS

This study included 56 patients who received spinal anesthesia. The pre-anesthesia evaluation was conducted using the STOP-Bang questionnaire. The patients were under spinal anesthesia with an average block level of T10. Dexmedetomidine was infused with a loading dose of 1 μg/kg over 10 min and a maintenance dose of 0.5 μg/kg/h until the end of the procedure. The SpO2 of the patients was recorded every 5 min.

RESULTS

The STOP-Bang score was negatively correlated with the lowest SpO2 (coefficient = -0.774, 95% confidence interval [CI]: -0.855 to -0.649, standard error [SE] = 0.054, P < 0.001). The item of "observed apnea" was the most correlated one with hypoxic events (odds ratio = 6.00, 95% CI: 1.086 to 33.145).

CONCLUSIONS

The STOP-BANG score was significantly correlated with the lowest SpO2 during spinal anesthesia, which enabled the prediction of meaningful hypoxia before it occurred in the sedated patients.

Dexmedetomidine & perioperative analgesia in children

Dexmedetomidine (DEX) is an anaesthetic agent that mimics natural deep sleep and produces minimal cardiorespiratory depression. As such, it is a very valuable option in the management of such a challenging population as paediatric patients. The main objective of this mini review was to evaluate the role of DEX as a perioperative analgesic in children receiving anaesthesia. We searched Google, Pubmed, Embase and the Cochrane Library for articles published between 2010 and 2021, and reviewed various of aspects of DEX, such as pharmacology, effectiveness, safety, and the most recent evidence on its clinical use as an analgesic in paediatric anaesthesia. We also include a cost estimate of perioperative analgesia with DEX.

Dexmedetomidine: What's New for Pediatrics? A Narrative Review

Over the past few years, despite the lack of approved pediatric labelling, dexmedetomidine’s (DEX) use has become more prevalent in pediatric clinical practice as well as in research trials. Its respiratory-sparing effects and bioavailability by various routes are only some of the valued features of DEX. In recent years the potential organ-protective effects of DEX, with the possibility for preserving neurocognitive function, has put it in the forefront of clinical and bench research. This comprehensive review focused on the pediatric literature but presents relevant, supporting adult and animal studies in order to detail the recent growing body of literature around the pharmacology, end-organ effects, organ-protective effects, alternative routes of administration, synergetic effects, and clinical applications, with considerations for the future.

Monitored Anesthesia Care for Cardiovascular Interventions

The interventional cardiology is growing and evolving. Many complex procedures are now performed outside the operating room to manage cardiovascular pathologies which had been traditionally treated with cardiac surgery. Appropriate sedation strategy is crucial for improved patient comfort and successful procedure while ensuring safety. Sedation for cardiovascular intervention is frequently challenging, especially in critically-ill, high-risk patients. This review addresses pre-procedure evaluation and preparation of patients, proper monitoring, commonly used sedatives and analgesics, and considerations for specific procedures. Appropriate depth of sedation and analgesia should be balanced with patient, procedural and institutional factors. Understanding of the pharmacology of sedatives/analgesics, vigilant monitoring, ability and proper preparation for management of potential complications may improve outcomes in patients undergoing sedation for cardiovascular procedures.

Sedation Strategies for Procedures Outside the Operating Room

With the rapid development of diagnostic and therapeutic procedures performed outside the operating room (OR), the need for appropriate sedation care has emerged in importance to ensure the safety and comfort of patients and clinicians. The preparation and administration of sedatives and sedation care outside the OR require careful attention, proper monitoring systems, and clinically useful sedation guidelines. This literature review addresses proper monitoring and selection of sedatives for diagnostic and interventional procedures outside the OR. As the depth of sedation increases, respiratory depression and cardiovascular suppression become serious, necessitating careful surveillance using appropriate monitoring equipment.