A new dosing protocol reduces dexmedetomidine-associated hypotension in critically ill surgical patients

Dexmedetomidine: a real-world safety analysis based on FDA adverse event reporting system database

Objective

Using the FDA adverse event reporting system (FAERS) database to analyze the safety profile of Dexmedetomidine and provide guidance for clinical application.

Methods

Data from the FAERS database from the first quarter of 2004 to the third quarter of 2023 were collected. Reporting odds ratio (ROR), the proportional reporting ratio (PRR), and the Bayesian confidence propagation neural network (BCPNN) were employed to detect and assess adverse events associated with Dexmedetomidine.

Results

A total of 1910 reports of Dexmedetomidine as the primary suspect drug were obtained. After screening, 892 preferred terms were obtained, including 52 new preferred terms not mentioned in the drug insert. The common adverse events of Dexmedetomidine include bradycardia, cardiac arrest, hypotension, diabetes insipidus, arteriospasm coronary and agitation. Notably, cardiac disorders exhibited the highest number of reports and the highest signal intensity in the system organ class. Among the new preferred terms, those with high signal intensity include transcranial electrical motor evoked potential monitoring abnormal, acute motor axonal neuropathy, trigemino-cardiac reflex, glossoptosis, floppy iris syndrome, phaeochromocytoma crisis, postresuscitation encephalopathy and diabetes insipidus.

Conclusion

This study mined and evaluated adverse events associated with Dexmedetomidine and also identified new adverse events. This could help alert clinicians to new adverse events not mentioned in the drug inserts, reducing the risk of drug.

Descriptive Analysis of Dexmedetomidine's Utility in a Palliative Care Unit at the End of Life

Context: Pain and symptom management at the end of life (EoL) can pose unique challenges, particularly when symptoms are refractory to conventional methods. Dexmedetomidine, originally approved for sedation in ventilated patients, has been demonstrated to be beneficial in pain management and palliative care settings by functioning as an alpha-2 agonist. Methods: A retrospective review of inpatient palliative care unit (IPU) records from January 2020 to December 2023 was conducted. Twenty-five adult patients receiving continuous dexmedetomidine for refractory pain at the EoL were identified. These patients were further evaluated for concurrent opioid, benzodiazepine, and chlorpromazine usage. Results: Patients experienced predominantly cancer-related pain, and had a median infusion duration of 5 days. Dexmedetomidine's initial dosing differed between the intensive care unit (ICU) and IPU settings. There was a trend toward a decreased opioid requirement 24 hours after initiation. Patients transferred from the ICU showed a progressive increase in opioid use. Conclusion: This study contributes to understanding dexmedetomidine's role in managing refractory symptoms at the EoL in the palliative care setting.

Dexmedetomidine in Palliative Care: A Versatile New Weapon Against Delirium and Pain-Systematic Review

Introduction: At the end of life, the prevalence of delirium and pain is high. Current therapy is not satisfactory. Dexmedetomidine could be useful in the control of delirium and pain but is not approved outside of intensive care setting. Our objectives are to evaluate existing evidence in the literature that assessed the efficacy of dexmedetomidine in pain and delirium control and its safety in palliative care patients outside intensive care units. This systematic review was prospectively registered with PROSPERO and included a risk of bias assessment. Methods: PubMed and SCOPUS were examined for literature published until 2023. Experimental, cohort, cross-sectional, case-control studies, and case series/reports were included if they evaluate the use of dexmedetomidine in delirium and/or pain management in hospitalized palliative care adult patients. Studies were excluded if they were carried out in intensive care units. Results: Of the initial 529 records, 14 were included. Although only two studies were randomized trials, most were small and only one had low risk of bias. In most case reports and in the two retrospective cohort studies, dexmedetomidine appears to be a better option for these symptoms, although differences were not significant in the randomized trials. Discussion: Dexmedetomidine seems to be a promising option for refractory pain and delirium and may contribute to a reduction in opioid administration to control pain. This is the first systematic review of dexmedetomidine in palliative care. Quality evidence is limited, but clinical properties of dexmedetomidine justify the conduction of controlled trials in palliative care.

Perioperative Hypotension in Patients Undergoing Orthopedic Upper Extremity Surgery with Dexmedetomidine Sedation: A Retrospective Study

(1) Background: limited data exist regarding the occurrence of hypotension associated with dexmedetomidine use and its risk factors in the context of intraoperative sedation for patients receiving peripheral nerve blocks. (2) Method: This single-center retrospective study assessed the incidence of hypotension in patients undergoing orthopedic upper extremity surgery with brachial plexus blockade. Patients were classified into three groups: group N (non-sedated), group M (midazolam), and group D (dexmedetomidine), based on their primary intraoperative sedative use. The primary outcome was the incidence of perioperative hypotension, defined as systolic blood pressure (SBP) < 90 mmHg or mean blood pressure (MBP) < 60 mmHg, at a minimum of two recorded time points during the intraoperative period and post-anesthesia care unit stay. Multivariable logistic models for the occurrence of hypotension were constructed for the entire cohort and group D. (3) Results: A total of 2152 cases (group N = 445, group M = 678, group D = 1029) were included in the analysis. The odds ratio for the occurrence of hypotension in group D was 5.68 (95% CI, 2.86 to 11.28) compared with group N. Concurrent use of a beta blocker, longer duration of surgery, and lower preoperative SBP and higher preoperative heart rate were identified as significant risk factors. (4) Conclusions: the increased risk of hypotension and the associated factors should be taken into account before using dexmedetomidine in these cases.

Evaluating the Effect of a Dosing and Titration Protocol on Dexmedetomidine-Induced Hypotension in Trauma Patients

BACKGROUND

Dexmedetomidine is an α-2 receptor agonist commonly used as a continuous infusion for sedation and analgesia; however, dose-dependent hypotension may limit its utility. Despite its widespread use, there is no consensus on appropriate dosing and titration.

OBJECTIVE

The objective of this study was to determine whether a dexmedetomidine dosing and titration protocol is associated with decreased rates of hypotension in trauma patients.

METHODS

This pre-post intervention study took place at a Level II trauma center in the Southeastern United States from August 2021 to March 2022 and included patients admitted by the trauma service to either the surgical trauma intensive care unit or intermediate care unit and received dexmedetomidine for greater than or equal to 6 hours. Patients were excluded if they were hypotensive or on vasopressors at baseline. The primary outcome was incidence of hypotension. Secondary outcomes included dosing and titration practices, initiation of a vasopressor, incidence of bradycardia, and time to goal Richmond Agitation Sedation Scale (RASS) score.

RESULTS

Fifty-nine patients met inclusion criteria: 30 in the pre-intervention group and 29 in the post-intervention group. Protocol adherence in the post group was 34% with a median of one violation per patient. Rates of hypotension were similar between the groups (60% vs. 45%, p = .243) but significantly lower in the post group patients with zero protocol violations (60% vs. 20%, p = .029). The post group also had a significantly lower maximal dose (1.1 vs. 0.7 μg/kg/hr, p < .001). There were no significant differences in the initiation of a vasopressor, incidence of bradycardia, or time to goal RASS.

CONCLUSION

Adherence to a dexmedetomidine dosing and titration protocol significantly decreased incidence of hypotension and maximal dexmedetomidine dose without increasing time to goal RASS score in critically ill trauma patients.

Opioid-sparing anesthesia with dexmedetomidine provides stable hemodynamic and short hospital stay in non-intubated video-assisted thoracoscopic surgery: a propensity score matching cohort study

OBJECTIVES

Dexmedetomidine is an alpha-2 agonist with anti-anxiety, sedative, and analgesic effects and causes a lesser degree of respiratory depression. We hypothesized that the use of dexmedetomidine in non-intubated video-assisted thoracic surgery (VATS) may reduce opioid-related complications such as postoperative nausea and vomiting (PONV), dyspnea, constipation, dizziness, skin itching, and cause minimal respiratory depression, and stable hemodynamic status.

METHODS

Patients who underwent non-intubated VATS lung wedge resection with propofol combined with dexmedetomidine (group D) or alfentanil (group O) between December 2016 and May 2022 were enrolled in this retrospective propensity score matching cohort study. Intraoperative vital signs, arterial blood gas data, perioperative results and treatment outcomes were analyzed. Of 100 patients included in the study (group D, 50 and group O, 50 patients), group D had a significantly lower degree of decrement in the heart rate and the blood pressure than group O. Intraoperative one-lung arterial blood gas revealed lower pH and significant ETCO₂. The common opioid-related side effects, including PONV, dyspnea, constipation, dizziness, and skin itching, all of which occurred more frequently in group O than in group D. Patients in group O had significantly longer postoperative hospital stay and total hospital stay than group D, which might be due to opioid-related side effects postoperatively.

CONCLUSIONS

The application of dexmedetomidine in non-intubated VATS resulted in a significant reduction in perioperative opioid-related complications and maintenance with acceptable hemodynamic performance. These clinical outcomes found in our retrospective study may enhance patient satisfaction and shorten the hospital stay.

Retrospective evaluation of dexmedetomidine dosing in a cohort of neurologically injured obese critically ill patients

Background

Dexmedetomidine is used in neurocritical care units (NCCUs) due to the light, dose-dependent sedation, and anxiolysis provided. It is unknown how to dose dexmedetomidine in obese patients. The primary objective is to assess the ability to achieve the goal Richmond Agitation Sedation Scale (RASS) measurements in obese patients with a neurological injury who are solely on dexmedetomidine before and after an institutional dosing change from actual body weight (ABW) to adjusted body weight (AdjBW).

Methods

This study included patients admitted to the NCCU with a neurological condition, required dexmedetomidine for at least 8 h as a sole sedative, and weighed ≥120% of ideal body weight. Percentage of RASS measurements within the goal range (-1 to +1) during the first 48 h while on dexmedetomidine were compared between patients dosed on ABW and on AdjBW.

Results

Sixty-eight patients in the ABW cohort and 72 patients in the AdjBW cohort were included. There were no statistical differences between the two groups (ABW vs. AdjBW) in the percent of RASS measurements in the goal range (53.2% ± 34.8% vs. 55% ± 37%; P = 0.78), mean weight (99.2 ± 26 vs. 96.8 ± 20.9 kg; P = 0.55), or the average dose of dexmedetomidine required to achieve first goal RASS score (0.4 ± 0.3 vs. 0.4 ± 0.3 mcg/kg/h; P = 0.98).

Conclusions

Dosing dexmedetomidine using AdjBW in obese critically ill neurologically injured patients for ongoing sedation resulted in no statistical difference in the percent of RASS measurements within the goal when compared to ABW dosing. Further studies are warranted.

Evaluation of Dexmedetomidine Dosing in Obese Critically Ill Patients

BACKGROUND

Dexmedetomidine is a highly selective α₂-adrenoreceptor agonist that produces dose-dependent sedation, anxiolysis, and analgesia without respiratory depression. Due to these ideal sedative properties, there has been increased interest in utilizing dexmedetomidine as a first-line sedative for critically ill patients requiring light sedation.

OBJECTIVE

To evaluate the ability to achieve goal intensive care unit (ICU) sedation before and after an institutional change of dosing from actual (ABW) to adjusted (AdjBW) body weight in obese patients on dexmedetomidine.

METHODS

This study included patients ≥ 18 years old, admitted to a surgical or medical ICU, required dexmedetomidine for at least 8 hours as a single continuous infusion sedative, and weighed ≥ 120% of ideal body weight. Percentage of RASS measurements within goal range (-1 to +1) during the first 48 hours after initiation of dexmedetomidine as the sole sedative agent or until discontinuation dosed on ABW compared to AdjBW was evaluated.

RESULTS

100 patients were included in the ABW cohort and 100 in the AdjBW cohort. The median dosing weight was significantly higher in the ABW group (95.9 [78.9-119.5] vs 82.2 [72.1-89.8] kg; p = 0.001). There was no statistical difference in percent of RASS measurements in goal range (61.5% vs 69.6%, p = 0.267) in patients that received dexmedetomidine dosed based on ABW versus AdjBW.

CONCLUSION

Dosing dexmedetomidine using AdjBW in obese critically ill patients for ongoing ICU sedation resulted in no statistical difference in the percent of RASS measurements within goal when compared to ABW dosing. Further studies are warranted.

Dexmedetomidine Reduces Incidences of Ventricular Arrhythmias in Adult Patients: A Meta-Analysis

Purpose

To assess the antiarrhythmic properties of dexmedetomidine in patients in the intensive care unit.

Methods

A literature review was conducted with Ovid MEDLINE (R), Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase, and Scopus. Study Selection. Randomized controlled trials were included, examining the incidence of ventricular arrhythmias, ventricular tachycardia, or ventricular fibrillation with dexmedetomidine compared to placebo or an alternative sedative agent. For each publication that met the selection criteria, the patient demographics, incidence of arrhythmias, mortality, and adverse events were collected. Data extraction was carried out by two authors independently.

Results

We identified 6 out of 126 studies that met the selection criteria for our meta-analysis, all of which focused on the perioperative cardiac surgery period. Patients receiving dexmedetomidine demonstrated a significant reduction of the overall incidence of ventricular arrhythmias (RR 0.35, 95% CI 0.16, 0.76). In particular, dexmedetomidine significantly decreased the risk of ventricular tachycardia compared with control (RR 0.25, 95% CI 0.08, 0.80, I² 0%). Regarding adverse events, dexmedetomidine significantly increased the frequency of bradycardia (RR 2.78 95% CI 2.00, 3.87). However, there was no significant difference in mortality (RR 0.59 95% CI 0.12, 3.02).

Conclusion

From this meta-analysis, we report a decreased incidence of ventricular tachycardia with dexmedetomidine in critically ill patients. This result favors the use of dexmedetomidine for its antiarrhythmic properties.

Minimizing Motion Artifacts in Intravital Microscopy Using the Sedative Effect of Dexmedetomidine

Among intravital imaging instruments, the intravital two-photon fluorescence excitation microscope has the advantage of enabling real-time 3D fluorescence imaging deep into cells and tissues, with reduced photobleaching and photodamage compared with conventional intravital confocal microscopes. However, excessive motion of organs due to involuntary movement such as breathing may result in out-of-focus images and severe fluorescence intensity fluctuations, which hinder meaningful imaging and analysis. The clinically approved alpha-2 adrenergic receptor agonist dexmedetomidine was administered to mice during two-photon fluorescence intravital imaging to alleviate this problem. As dexmedetomidine blocks the release of the neurotransmitter norepinephrine, pain is suppressed, blood pressure is reduced, and a sedation effect is observed. By tracking the quality of focus and stability of detected fluorescence in two-photon fluorescence images of fluorescein isothiocyanate-sensitized liver vasculature in vivo, we demonstrated that intravascular dexmedetomidine can reduce fluorescence fluctuations caused by respiration on a timescale of minutes in mice, improving image quality and resolution. The results indicate that short-term dexmedetomidine treatment is suitable for reducing involuntary motion in preclinical intravital imaging studies. This method may be applicable to other animal models.

Standard- versus High-Dose Dexmedetomidine for Sedation in the Intensive Care Unit

Background: Dexmedetomidine is a commonly used sedative in the intensive care unit (ICU), however the use of higher, off label dosing has yet to be elucidated. A dose limitation protocol was implemented at our institution allowing for comparison of dexmedetomidine doses. Objective: The purpose of this study is to evaluate time spent within goal Richmond Agitation Sedation Scale (RASS) range with standard-dosing of dexmedetomidine ≤1 mcg/kg/hour (SD group) compared to high-dose >1 mcg/kg/hour (HD group). Secondary outcomes included days requiring mechanical ventilation, concomitant sedation, and incidence of hypotension or bradycardia. Methods: This retrospective chart review of adult ICU patients at a single academic medical center included patients who required at least 24 hours of mechanical ventilation and received dexmedetomidine monotherapy for at least 4 hours. Patients were excluded for intubations at an outside hospital, continuous neuromuscular blocking infusions, or Glasgow Coma Score ≤4. Results: A total of 144 patients met inclusion criteria (n = 121 SD group and n = 23 HD group). The SD group spent a greater time within goal RASS range compared to the HD group (84.5% [IQR 47-100] vs 45.5% [IQR 30.1-85.4], P = .013). The SD group also had shorter durations of both dexmedetomidine infusion and mechanical ventilation, and required less concomitant sedation. There was no difference in hypotension or bradycardia. Conclusion: This study further adds to the literature that administration of high-dose dexmedetomidine does not appear to confer additional benefit over standard doses for ICU patients requiring mechanical ventilation. Application of this data may support lower institutional maximum doses.

Dexmedetomidine-induced hemodynamic instability in patients undergoing orthopedic upper limb surgery under brachial plexus block: a retrospective study

Background

Hemodynamic instability is a frequent adverse effect following administration of dexmedetomidine (DMED). In this study, we evaluated the incidence of DMED-induced hemodynamic instability and its predictive factors in clinical regional anesthesia practice.

Methods

One hundred sixteen patients who underwent orthopedic upper limb surgery under brachial plexus block with intravenous DMED administration were retrospectively identified. The primary outcome was the incidence of DMED-induced hemodynamic instability. The participants were allocated to a stable or unstable group by their hemodynamic instability status. Patients’ characteristics were compared between the groups. The relationship between the potential risk factors and development of DMED-induced hemodynamic instability was analyzed with a logistic regression model.

Results

DMED-induced hemodynamic instability was observed in 14.7% of patients (17/116). The unstable group had more women than the stable group (76.5% vs. 39.4%, P = 0.010). When patients were classified into four subgroup according to body mass index (underweight, normal weight, overweight, and obesity), there was significant difference in the composition of the subgroups in the two groups (P = 0.008). In univariate analysis, female sex, obesity, and pre-existing hypertension were significant predictors of DMED-induced hemodynamic instability. Multivariate analysis demonstrated that female sex (adjusted OR 3.86, CI 1.09; 13.59, P = 0.036) and obesity (adjusted OR 6.41, CI 1.22; 33.57, P = 0.028) were independent predictors of DMED-induced hemodynamic instability.

Conclusions

Female and obese patients are more likely to have hemodynamic instability following intravenous DMED administration in clinical regional anesthesia practice. This study suggests that DMED dose may be diminished to prevent hypotensive risk in these populations.

Trial registration

This article was retrospectively registered at WHO clinical trial registry platform (Trial number: KCT0005977).

Circulating microRNA-30a-5p, microRNA-101-3p, microRNA-140-3p and microRNA-141-3p as potential biomarkers for dexmedetomidine response in pediatric patients

PURPOSE

The aim of this study was to investigate the expression levels of plasma miR-30a-5p, miR-101-3p, miR-140-3p and miR-141-3p and their relationship to dexmedetomidine efficacy and adverse effects in pediatric patients.

METHODS

The expression levels of miR-30a-5p, miR-101-3p, miR-140-3p and miR-141-3p were measured by qRT-PCR in plasma of 133 pediatric patients receiving dexmedetomidine for preoperative sedation. We analyzed the relationship between miRNA abundance and dexmedetomidine response, including sedative effect and adverse effects, and assessed the predictive power of miRNAs for drug response.

RESULTS

Among 133 pediatric patients, 111 patients were dexmedetomidine responders (UMSS ≥ 2) and 22 patients were non-responders (UMSS < 2). We observed higher expression levels of miR-101-3p and miR-140-3p in dexmedetomidine responders compared with non-responders (P < 0.05, P < 0.0001). In contrast, there was no significant difference in the expression levels of miR-30a-5p and miR-141-3p between responders and non-responders (P > 0.05). The plasma levels of miR-101-3p and miR-30a-5p were markedly downregulated in patients who experienced hypotension and bradycardia, respectively (P < 0.05). MiR-101-3p and miR-140-3p demonstrated a potential discriminatory ability between dexmedetomidine responders and non-responders, with AUC of 0.64 (P < 0.05) and 0.77 (P < 0.0001), respectively. The AUC of miR-101-3p in distinguishing patients without hypotension was 0.63 (P < 0.05). The AUC of miR-30a-5p in distinguishing patients without bradycardia was 0.74 (P < 0.05).

CONCLUSION

Our study demonstrated that circulating miR-101-3p, miR-140-3p and miR-30a-5p might be used as a blood-based marker for dexmedetomidine efficacy and safety in pediatric patients.

Hemodynamic Adverse Effects of Dexmedetomidine and Propofol in a Critically Ill Trauma and Surgical Population: A Retrospective Cohort

BACKGROUND

Propofol and dexmedetomidine may cause hemodynamic adverse effects (AEs) and more data are needed in a trauma and surgical population.

OBJECTIVE

The objective of this study was to evaluate the rate of hemodynamic AEs requiring an intervention between dexmedetomidine and propofol in a critically ill trauma and surgical population.

METHODS

This was a retrospective cohort study at a Level 1 trauma center. Intensive care unit patients admitted from October 1, 2017, through October 31, 2018, were divided into two groups: dexmedetomidine or propofol. The primary end point was the proportion of patients who required a therapeutic intervention for a hemodynamic AE within the first 24 hr of initiation of dexmedetomidine or propofol.

RESULTS

A total of 800 charts were reviewed and 85 patients (dexmedetomidine [n = 35] and propofol [n = 50]) were included. The study population consisted of Caucasian (86%) males (61%) with a median age of 61 [interquartile range-IQR 48, 72], and 18% and 24% required antihypertensive and vasopressor agents, respectively. No difference in the primary outcome was observed (17 [49%] vs. 27 [54%], p = .624). There was no difference in the overall incidence of hemodynamic AE (18 [51%] vs. 30 [60%], p = .433). Dexmedetomidine patients had a greater decrease in median heart rate (HR) compared with the propofol (23 [IQR 16, 41] vs. 14 [IQR 5, 24] beats/min, p = .002).

CONCLUSIONS

The rate of hemodynamic AEs requiring therapeutic interventions was similar between dexmedetomidine and propofol in a critically ill trauma and surgical population; however, dexmedetomidine may be associated with a larger decrease in HR.

Differences in efficacy and safety of midazolam vs. dexmedetomidine in critically ill patients: A meta-analysis of randomized controlled trial

The present study aimed to compare the efficacy and safety of dexmedetomidine and midazolam in patients that are critically ill. Full text articles reporting the clinical effects and complications of dexmedetomidine and midazolam were retrieved from multiple databases. Review Manager 5.0 was adopted for meta-analysis, sensitivity and bias analysis. Finally, a total of 1,379 patients from 8 studies, which met the eligibility criteria, were included. The meta-analysis suggested that the length of stay at the intensive care unit [mean absolute difference (MD)=-1.80; 95% confidence interval (CI), -2.13, -1.48; P<0.00001; P-value for heterogeneity=0.41; I²=3%], time to extubation (MD=-2.18; 95% CI, -2.66, -1.69; P<0.00001; P-value for heterogeneity=0.84; I²=0%) and delirium (MD=0.46; 95% CI, 0.37, 0.57; P<0.00001; P-value for heterogeneity=0.65; I²=0%) was higher following midazolam treatment compared with dexmedetomidine, while bradycardia [odds ratio (OR)=5.03; 95% CI, 3.86, 6.57; P<0.00001; P-value for heterogeneity=0.13; I²=38%] was higher in dexmedetomidine treated patients compared with midazolam. However, no difference was observed in the incidence of hypotension (OR=0.88; 95% CI, 0.70, 1.10; P=0.26; P-value for heterogeneity=0.99; I²=0%) and mortality (OR=0.96; 95% CI, 0.74, 1.25; P=0.77; P-value for heterogeneity=0.99; I²=0%). Taking clinical effects and safety into account, the present study suggested dexmedetomidine to be the preferred option of anesthesia for patients that are critically ill.

Safety of dexmedetomidine in the cardiac intensive care unit

AIMS

Dexmedetomidine is one of the sedative agents recommended by the Society of Critical Care Medicine as a preferred option over benzodiazepines in critically ill, mechanically ventilated patients. Little data exists describing sedation in the cardiac intensive care unit (CICU). The purpose of this study was to determine the prevalence of adverse events in CICU patients treated with dexmedetomidine.

METHODS AND RESULTS

This was a retrospective cohort analysis of patients >18 years old admitted to the University of Michigan CICU from June 2014 to October 2019 who received dexmedetomidine therapy. The primary outcome was the composite of adverse events including bradycardia, hypotension, increasing vasopressor/inotrope requirements, and asystole. Secondary outcomes included individual components of the primary outcome. Patients that experienced adverse events were compared to those that did not experience adverse events to identify risk factors for adverse events. A total of 197 patients were included. There were 116 adverse events in 106 patients. Hypotension was the most common adverse event, making up 60.3% of adverse events reported. Increased vasopressor requirement and bradycardia both occurred in 22 patients (18.9%). Asystole occurred in two patients. B-type natriuretic peptide (BNP) levels were significantly higher in those experiencing an adverse event (848 pg/mL vs. 431 pg/mL; P = 0.03).

CONCLUSIONS

Patients admitted to the CICU experienced a high rate of adverse events with dexmedetomidine use. Those experiencing adverse events were more likely to have a higher BNP. Future studies should explore the safety of alternative sedative agents to ascertain safe pharmacological options for patients admitted to the CICU.

Hemodynamic Effects of Dexmedetomidine in Adults With Reduced Ejection Fraction Heart Failure

BACKGROUND

Dexmedetomidine (DEX) can cause hypotension complicating its use in critically ill patients with labile hemodynamics secondary to an underlying disease state such as heart failure. The aim of this study was to determine the effect of DEX on mean arterial pressure (MAP) in nonsurgical patients with heart failure and reduced ejection fraction (HFrEF).

METHODS

This retrospective single-center cohort study evaluated patients who received DEX in the cardiac care and medical intensive care units at a large academic hospital. The primary end point was the change in MAP within 6 hours following DEX initiation.

RESULTS

Sixty-five patients with HFrEF diagnosis were compared 1:1 to a control group without HFrEF. Both groups experienced a decrease in MAP over the study period. Patients with HFrEF had a greater absolute percentage reduction in MAP 1 hour following DEX initiation compared to the control group (-9.6% vs -5.2%; P < .01). When accounting for the combined effect of DEX initiation and HFrEF diagnosis on the primary end point, patients with HFrEF did not have a significant difference in MAP compared to the control group over the study period.

CONCLUSIONS

Within 6 hours following DEX initiation, both groups experienced a decrease in MAP. The effect of DEX on MAP over the composite time period was not found to be significantly different in the HFrEF group compared to the non-HFrEF group. However, patients with HFrEF experienced a greater reduction in MAP in the first hour following DEX initiation compared to the non-HFrEF group. Prospective studies are needed to evaluate the effect of DEX on patients with acute decompensated HFrEF compared to patients with compensated HFrEF.

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.

Dexmedetomidine: present and future directions

Dexmedetomidine is a potent, highly selective α-2 adrenoceptor agonist, with sedative, analgesic, anxiolytic, sympatholytic, and opioid-sparing properties. Dexmedetomidine 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. Dexmedetomidine may produce less delirium than other sedatives or even prevent delirium. The analgesic effect of dexmedetomidine is not strong; however, it can be administered as a useful analgesic adjuvant. As an anesthetic adjuvant, dexmedetomidine decreases the need for opioids, inhalational anesthetics, and intravenous anesthetics. The sympatholytic effect of dexmedetomidine may provide stable hemodynamics during the perioperative period. Dexmedetomidine-induced cooperative sedation with minimal respiratory depression provides safe and acceptable conditions during neurosurgical procedures in awake patients and awake fiberoptic intubation. Despite the lack of pediatric labelling, dexmedetomidine has been widely studied for pediatric use in various applications. Most adverse events associated with dexmedetomidine occur during or shortly after a loading infusion. There are some case reports of dexmedetomidine-related cardiac arrest following severe bradycardia. Some extended applications of dexmedetomidine discussed in this review are promising, but still limited, and further research is required. The pharmacological properties and possible adverse effects of dexmedetomidine should be well understood by the anesthesiologist prior to use. Moreover, it is necessary to select patients carefully and to determine the appropriate dosage of dexmedetomidine to ensure patient safety.

Comparative evaluation of intrathecal bupivacaine alone and bupivacaine combined with dexmedetomidine in cesarean section using spinal anesthesia: a meta-analysis

Objective

This meta-analysis was performed to evaluate the effect of spinal anesthesia (SA) using bupivacaine combined with dexmedetomidine (DEX) in cesarean section, analyze the adverse drug reactions induced by this mixture, and provide a reference for rational drug use.

Methods

Randomized controlled trials were obtained from the PubMed, Cochrane Library, and Embase databases. The primary outcome measure was the time to the highest sensory block level (min), and the secondary outcome measure was adverse effects.

Results

The time to the highest sensory block level was significantly shorter in the bupivacaine-DEX group than in the control group (standardized mean difference, −0.23; 95% confidence interval, −0.43 to −0.03). The incidence of shivering during the process of anesthesia, especially at a dose of 5 µg DEX, was significantly lower in the bupivacaine-DEX group than in the control group (odds ratio, 0.26; 95% confidence interval, 0.14–0.49). No significant differences were observed in the symptoms of hypotension, bradycardia, nausea/vomiting, or pruritus.

Conclusion

Compared with the use of bupivacaine alone for SA in cesarean section, adding dexmedetomidine during SA can significantly shorten the onset time and decrease the rate of shivering during anesthesia.

A Pilot Study Implementing a Protocol Using Dexmedetomidine as a Safe Alternative to Traditional Sedation to Decrease Ventilator Days for Patients Difficult to Extubate

BACKGROUND

Traditional sedation for mechanically ventilated patients causes delirium, which increases the patients' length of stay while hospitalized. When extubation is attempted, these medications must be discontinued because of the side effect of respiratory depression, leaving patients anxious and agitated, delaying extubation and prolonging the need for mechanical ventilation. Dexmedetomidine is a safe alternative sedative that does not cause delirium or respiratory depression. During the weaning process, dexmedetomidine can be continued, allowing the patient to remain calm and successfully extubated.

OBJECTIVES

The aim of this study is to decrease the length of stay for mechanically ventilated patients by implementing a dexmedetomidine protocol for difficult-to-extubate patients during the weaning process.

METHODS

A preintervention/postintervention design pilot study was done comparing the patient mean of length of stay on mechanical ventilation. A Mann-Whitney U test was used because of the small sample size.

RESULTS

Over the 3-month implementation period, 15 patients received dexmedetomidine. None of the patients experienced adverse reactions while on dexmedetomidine. There was a trend of decreasing mechanical ventilation length of stay but no significant difference was noted between the preimplementation and postimplementation groups.

CONCLUSION

Dexmedetomidine was a safe alternative to traditional sedation for difficult-to-extubate patients when a bolus dose was not given.

Perinatal and neonatal use of sedation and analgesia

Optimal obstetric and neonatal care requires the provision of adequate analgesia for painful procedures. However, anesthetic and analgesic agents have the potential to adversely impact the developing fetal/neonatal brain. In this setting, clinicians must assess the risks and benefits of pharmacologic anesthesia and analgesia for specific indications in this population. General anesthesia is required for non-obstetric surgery and cesarean section in the absence of neuraxial anesthesia for the health of the mother and fetus. Although experimental data raise concerns, human data are reassuring and future research may focus on neuroprotective adjuncts in the setting of repeated or prolonged anesthetic exposures. Opioid analgesia is standard of care for preterm infants undergoing major procedures including invasive surgery and endotracheal intubation. The use of opioids for agitation resulting from mechanical ventilation is controversial, but prevalent. Randomized and retrospective studies detect short-term toxicity with inconclusive long-term impact, suggesting the need to explore alternative therapies.

Predictors of dexmedetomidine-associated hypotension in critically ill patients

BACKGROUND

Dexmedetomidine is commonly used for sedation in the Intensive Care Unit (ICU), and its use may be associated with hypotension. We sought to determine predictors of dexmedetomidine-associated hypotension.

METHODS

Retrospective, single-center study of 283 ICU patients in four adults ICUs over a 12 month period. Univariate analyses were performed to determine factors associated with dexmedetomidine-related hypotension. Risk factors significant at the 0.20 level in the univariate analysis were considered for inclusion into a step-wise multiple logistical regression model.

RESULTS

Hypotension occurred in 121 (42.8%) patients with a median mean arterial pressure (MAP) nadir of 54 mmHg. Univariate analyses showed an association between hypotension and age (P = 0.03), Acute Physiology and Chronic Health Evaluation II (APACHE II) score (P = 0.02), baseline MAP (<0.001), admission to the cardiothoracic ICU (P = 0.05), history of coronary artery disease (P = 0.02), and postcardiac surgery (P = 0.0009). Admission to the medical ICU was associated with a decrease in development in hypotension (P = 0.03). There was a trend for hypotension with weight (P = 0.09) and history of congestive heart failure (P = 0.12) Only MAP prior to initiation (odds ratio [OR] 0.97, 95% confidence interval [95% CI] 0.95-0.99; P < 0.0001), APACHE II scores (OR 1.06, 95% CI 1.01-1.12; P = 0.017), and history of coronary artery disease (OR 0.48, 95% CI 0.26-0.90, P = 0.022) were independently associated with hypotension by multivariable analysis.

CONCLUSIONS

Dexmedetomidine-associated hypotension is common. Preexisting low blood pressure, history of coronary artery disease, and higher acuity were identified as independent risk factors for dexmedetomidine-associated hypotension.

The Effects of Dexmedetomidine Administration on Postoperative Blood Glucose Levels in Diabetes Mellitus Patients Undergoing Spinal Anesthesia: A Pilot Study

Background

Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist with sedative and sympatholytic effects. It inhibits the stress response and insulin secretion. Therefore, postoperative changes to blood glucose levels were investigated when DEX was intraoperatively infused for sedation purposes in diabetic patients under spinal anesthesia.

Methods

Twenty diabetic patients were randomly allocated to two groups (n = 10). Group A patients were infused with DEX at a dose of 0.4 - 0.8 μg/kg/hour and group B (control) patients were infused with the same volume of normal saline. The blood glucose levels were measured preoperatively and at 1, 3, 6, 12, and 24 hours postoperatively.

Results

There was no statistically significant difference between the blood glucose levels in groups A and B up to 24 hours postoperatively (P = 0.088). A statistically significant difference in the blood glucose level was not demonstrated 24 hours after surgery in comparison with the baseline level in Group A. The blood glucose level significantly decreased at three hours in group B in comparison with the level at baseline (P = 0.007) and increased at 24 hours (P = 0.037).

Conclusions

An intraoperative DEX infusion maintains blood glucose levels at a constant level relative to baseline in diabetic patients within 24 hours postoperatively. The frequency of hyperglycemia was low in group A in the perioperative period compared with that in the control group (group B).

Risk Factors for Dexmedetomidine-Associated Hemodynamic Instability in Noncardiac Intensive Care Unit Patients

BACKGROUND

The reported incidence of hypotension and bradycardia in patients receiving dexmedetomidine for sedation commonly exceeds 50%. In this study, we describe the incidence of, patient- and treatment-specific risk factors for, and clinical significance of dexmedetomidine-associated hemodynamic instability.

METHODS

This retrospective cohort study was conducted in critically ill adults receiving dexmedetomidine for sedation at Mayo Clinic Hospital in Rochester, MN, during a 1-year period. The primary end point was hemodynamic instability: a composite of hypotension and/or bradycardia, defined as systolic blood pressure <80 mm Hg, diastolic blood pressure <50 mm Hg, or heart rate <50 beats per minute during dexmedetomidine therapy. Cox proportional hazards models were constructed to determine hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk factors of hemodynamic instability.

RESULTS

Hemodynamic instability occurred in 197 of the analyzed 300 patients receiving dexmedetomidine, resulting in a cumulative incidence of 71% at 24 hours via Kaplan-Meier estimation. In addition to dexmedetomidine, univariate analysis identified age, vasopressor use, low baseline arterial blood pressure, and concomitant sedatives as associated with increased risk of hemodynamic instability. Multivariable analysis demonstrated associations between age (HR, 1.23 per 10 years, 95% CI, 1.10-1.38) and low baseline blood pressure (HR, 2.42 at dexmedetomidine initiation, 95% CI, 1.68-3.49) and risk of hemodynamic instability. Variables such as concomitantly administered cardiac medications or sedative therapies and dexmedetomidine infusion rates >0.7 μg/kg/h were not found to be predictors of hemodynamic instability among the analyzed sample.

CONCLUSIONS

Hemodynamic instability commonly occurs in critically ill adults receiving dexmedetomidine, with more than two thirds of this cohort experiencing hypotension and/or bradycardia within 24 hours of initiation. Increasing age and low baseline arterial blood pressure were associated with the development of hemodynamic instability. These findings suggest that clinicians should be aware of the potential risk of hemodynamic instability when using dexmedetomidine in patients with advanced age or low baseline arterial blood pressure.

Predictors of dexmedetomidine-associated hypotension in critically ill patients

Background:

Dexmedetomidine is commonly used for sedation in the Intensive Care Unit (ICU), and its use may be associated with hypotension. We sought to determine predictors of dexmedetomidine-associated hypotension.

Methods:

Retrospective, single-center study of 283 ICU patients in four adults ICUs over a 12 month period. Univariate analyses were performed to determine factors associated with dexmedetomidine-related hypotension. Risk factors significant at the 0.20 level in the univariate analysis were considered for inclusion into a step-wise multiple logistical regression model.

Results:

Hypotension occurred in 121 (42.8%) patients with a median mean arterial pressure (MAP) nadir of 54 mmHg. Univariate analyses showed an association between hypotension and age (P = 0.03), Acute Physiology and Chronic Health Evaluation II (APACHE II) score (P = 0.02), baseline MAP (<0.001), admission to the cardiothoracic ICU (P = 0.05), history of coronary artery disease (P = 0.02), and postcardiac surgery (P = 0.0009). Admission to the medical ICU was associated with a decrease in development in hypotension (P = 0.03). There was a trend for hypotension with weight (P = 0.09) and history of congestive heart failure (P = 0.12) Only MAP prior to initiation (odds ratio [OR] 0.97, 95% confidence interval [95% CI] 0.95–0.99; P < 0.0001), APACHE II scores (OR 1.06, 95% CI 1.01–1.12; P = 0.017), and history of coronary artery disease (OR 0.48, 95% CI 0.26–0.90, P = 0.022) were independently associated with hypotension by multivariable analysis.

Conclusions:

Dexmedetomidine-associated hypotension is common. Preexisting low blood pressure, history of coronary artery disease, and higher acuity were identified as independent risk factors for dexmedetomidine-associated hypotension.

Comparison of the effects of propofol and emulsified isoflurane alone or combined with dexmedetomidine on induction of anesthesia in dogs

OBJECTIVE

To compare the respective effects of propofol and emulsified isoflurane administered alone and in combination with dexmedetomidine on the quality of induction of anesthesia, physiological variables and recovery in dogs.

STUDY DESIGN

Prospective, randomized, experimental trial.

ANIMALS

Thirty-six adult mixed-breed dogs.

METHODS

Animals were randomly assigned to one of four induction protocols: propofol alone (group P); emulsified isoflurane alone (group EI); both propofol and dexmedetomidine (group PD), or both emulsified isoflurane and dexmedetomidine (group EID). Pulse rate (PR), respiratory rate (fR ), non-invasive arterial blood pressure and arterial blood gases were measured at baseline, before induction, immediately after intubation (time 0), and at 5 minute intervals until the dog began to swallow and the trachea was extubated. The quality of induction and recovery, and degree of ataxia were scored by a single investigator unaware of group assignment. The durations of anesthesia and recovery, and the incidence of adverse events were recorded.

RESULTS

There were no clinically significant differences among the groups in induction quality. Systolic arterial pressure was lower in EID compared with P at 5 minutes. PR and fR were lower in PD and EID compared with P after induction. The PaCO2 at 5 minutes was higher than at baseline in group P. Ataxia score was lower in EID than in P. Time from induction to extubation and time from extubation to sternal recumbency were lower in EID compared with PD.

CONCLUSIONS AND CLINICAL RELEVANCE

There were no clinically significant differences among the groups in induction quality. In PD and EID, but not in P, PR and fR were decreased after induction. The EID combination resulted in smooth and rapid induction and recovery and thus may be useful clinically for induction of anesthesia.

Dexmedetomidine decreases inhibitory but not excitatory neurotransmission to cardiac vagal neurons in the nucleus ambiguus

Dexmedetomidine, an α2 adrenergic agonist, is a useful sedative but can also cause significant bradycardia. This decrease in heart rate may be due to decreased central sympathetic output as well as increased parasympathetic output from brainstem cardiac vagal neurons. In this study, using whole cell voltage clamp methodology, the actions of dexmedetomidine on excitatory glutamatergic and inhibitory GABAergic and glycinergic neurotransmission to parasympathetic cardiac vagal neurons in the rat nucleus ambiguus was determined. The results indicate that dexmedetomidine decreases both GABAergic and glycinergic inhibitory input to cardiac vagal neurons, with no significant effect on excitatory input. These results provide a mechanism for dexmedetomidine induced bradycardia and has implications for the management of this potentially harmful side effect.

Cardiovascular Effects of Continuous Dexmedetomidine Infusion Without a Loading Dose in the Pediatric Intensive Care Unit

BACKGROUND

Use of dexmedetomidine in pediatric critical care is common, despite lack of prospective studies on its hemodynamic effects.

OBJECTIVE

To describe cardiovascular effects in critically ill children treated with a constant continuous infusion of dexmedetomidine without a loading dose at highest Food and Drug Administration-approved adult dose.

METHODS

Prospective, pilot study of 17 patients with dexmedetomidine infused at a rate of 0.7 μg/kg/h for 6 to 24 hours. Heart rate (HR) and blood pressure (BP) values over time were analyzed by a random effects mixed model.

RESULTS

Patients with median age of 1.6 years (1 month to 17 years) and median weight of 11.8 kg (2.8-84 kg) received an infusion for a mean of 16 ± 7.2 hours. There were no cardiac conduction abnormalities. One patient required discontinuation of infusion for predetermined low HR termination criteria at hour 13 of infusion; there was no clinical compromise and it coincided with planned extubation. Decreased HR of 20% from baseline was found in 35% of patients. The mean HR reduction was largest at hour 13 of infusion with a decrease of 13 ± 17 bpm from baseline, but HR changes over time were not statistically significant. Blood pressure effects included a decrease in 12% and an increase in 29%. There was a small but statistically significant increase in systolic BP of 0.4 mm Hg/h of infusion, P < .001.

CONCLUSION

A continuous infusion of 0.7 μg/kg/h of dexmedetomidine without a loading dose for up to 24 hours in critically ill children had tolerable effects on HR and BP.

Neonatal pain control and neurologic effects of anesthetics and sedatives in preterm infants

Preclinical and clinical studies have demonstrated the adverse consequences of untreated pain and stress on brain development in the preterm infant. Sucrose has widely been implemented as standard therapy for minor procedural pain. Anesthetics are commonly utilized in preterm infants during major surgery. Pharmacologic agents (benzodiazepines and opioids) have been examined in clinical trials of preterm infants requiring invasive mechanical ventilation. Controversy exists regarding the safety and long-term impact of these interventions. Ongoing multidisciplinary research will help define the impact of these agents and identify potential alternative therapies.

Role of dexmedetomidine in adults in the intensive care unit: an update

PURPOSE

The role of dexmedetomidine for the management of pain, agitation, and delirium in adult patients in the intensive care unit (ICU) is reviewed and updated.

SUMMARY

Searches of MEDLINE (July 2006-March 2012) and an extensive manual review of journals were performed. Relevant literature with a focus on data published since our last review in 2007 was evaluated for topic relevance and clinical applicability. Optimal management of pain, agitation, and delirium in ICUs requires a systematic and multimodal approach aimed at providing comfort while maximizing outcomes. Dexmedetomidine is among multiple agents, including opioids, propofol, benzodiazepines, and antipsychotics, used to facilitate and increase patients' tolerability of mechanical ventilation. This article reviews the newest evidence available for dexmedetomidine use for sedation and analgesia in medical-surgical ICUs. Adverse effects associated with dexmedetomidine were similar among the studies examined herein. The most common adverse effects with dexmedetomidine were bradycardia and hypotension, in some cases severe enough to warrant the use of vasoactive support. Due to the adverse events associated with rapid dosage adjustment and bolus therapy, dexmedetomidine may not be the best agent for treating acute agitation.

CONCLUSION

In medical-surgical ICUs, dexmedetomidine may be a viable non-benzodiazepine option for patients with a need for light sedation. In cardiac surgery patients, dexmedetomidine appears to offer no advantage over propofol as the initial sedative. The role of dexmedetomidine in unique patient populations such as neurosurgical, trauma, and obstetrics is yet to be established.

Influence of dexmedetomidine therapy on the management of severe alcohol withdrawal syndrome in critically ill patients

PURPOSE

Although benzodiazepines are first-line drugs for alcohol withdrawal syndrome (AWS), rapidly escalating doses may offer little additional benefit and increase complications. The purpose of this study was to evaluate dexmedetomidine's impact on benzodiazepine requirements and hemodynamics in AWS.

MATERIALS AND METHODS

This retrospective case series evaluated 33 critically ill adults with a primary diagnosis of AWS from 2006 to 2012 at an academic medical center.

RESULTS

Dexmedetomidine began a median (interquartile range) of 11 (2, 32) hours into intensive care unit admission and was titrated to an infusion rate of 0.7 (0.4, 0.7) μg kg(-1) h(-1) to achieve the desired depth of sedation. In the 12 hours after dexmedetomidine began, patients experienced a 20-mg reduction in median cumulative benzodiazepine dose used (P < .001), a 14-mm Hg lower mean arterial pressure (P = .03), and a 17-beats/min reduction in median heart rate (P < .001). Four (12%) patients experienced hypotension (systolic blood pressure <80 mm Hg) during therapy, and there were no cases of bradycardia (heart rate <40 beats/min).

CONCLUSION

Dexmedetomidine decreased benzodiazepine requirements and improved the overall hemodynamic profile of patients with severe AWS. These results provide promising evidence about the potential benefit of dexmedetomidine for AWS.

Dexmedetomidine for the treatment of alcohol withdrawal syndrome: rationale and current status of research

Dexmedetomidine is currently used in the US in the treatment of alcohol withdrawal syndrome (AWS) in the intensive care unit (ICU) setting, although data to support this practice are limited. Dexmedetomidine targets the noradrenergic system, an important but frequently overlooked secondary mechanism in the development of AWS, and, in doing so, may reduce the need for excessive benzodiazepine use which can increase the risk of γ-aminobutyric acid (GABA)-mediated deliriogenesis and respiratory depression. The purpose of this narrative review is to evaluate available literature reporting on the safety and efficacy of dexmedetomidine for AWS in the ICU setting. An English-language MEDLINE search (1966 to July 2013) was performed to identify articles evaluating the efficacy and safety of dexmedetomidine for AWS. Case series, case reports and controlled trials were evaluated for topic relevance and clinical applicability. Reference lists of articles retrieved through this search were reviewed to identify any relevant publications. Studies focusing on the safety and efficacy of dexmedetomidine for AWS in humans were selected. Studies were included if they were published as full articles; abstracts alone were not included in this review. Eight published case studies and case series were identified. Based on a limited body of evidence, dexmedetomidine shows promise as a potentially safe and possibly effective adjuvant treatment for AWS in the ICU. Prospective, well-controlled studies are needed to confirm the safety and efficacy of the use of dexmedetomidine in AWS.

A case-based approach to the practical application of dexmedetomidine in critically ill adults

Dexmedetomidine is a selective α(2) -adrenoceptor agonist that offers unique sedation because patients are readily awakened while administration continues and the drug does not suppress the respiratory center. Limitations of use include higher acquisition cost, inability to produce deep sedation, and bradycardia and hypotension. Using a case-based approach, the purpose of this review was to qualitatively assess the role of dexmedetomidine in the care of the critically ill and in the management of alcohol withdrawal, and to formulate recommendations regarding its clinical application. Sixty-six studies were identified that investigated dexmedetomidine for the provision of sedation. These studies were heterogeneous in design and patient populations; most investigated patients did not require heavy sedation, and few used propofol as the comparator. In general, though, the aggregate results of all studies demonstrate that dexmedetomidine provides comfort, possibly shortens the duration of mechanical ventilation to facilitate extubation, reduces the occurrence of acute brain dysfunction, and facilitates communication, but the drug is associated with hemodynamic instability and requires the supplemental use of traditional sedative and analgesic agents. These outcomes need to be substantiated in additional studies that include assessments of cost-effectiveness. Dexmedetomidine should be considered when patients require mild to moderate levels of sedation of short to intermediate time frames, and they qualify for daily awakenings with traditional sedative therapies. The data for dexmedetomidine in relation to alcohol withdrawal are limited to 12 retrospective reports representing a total of 127 patients. Its role for this indication requires further study, but it may be considered as adjunctive therapy when clinicians are concerned about respiratory suppression associated with escalating doses of γ-aminobutyric acid agonists. Regardless of the indication for dexmedetomidine, the practitioner must closely monitor patient comfort and the occurrence of hemodynamic deviations with the realization that as-needed administration of traditional sedatives and analgesics will be required and some degree of bradycardia and hypotension expected but intervention rarely required.

Sedation and analgesia in mechanically ventilated preterm neonates: continue standard of care or experiment?

Attention to comfort and pain control are essential components of neonatal intensive care. Preterm neonates are uniquely susceptible to pain and agitation, and these exposures have a negative impact on brain development. In preterm neonates, chronic pain and agitation are common adverse effects of mechanical ventilation, and opiates or benzodiazepines are the pharmacologic agents most often used for treatment. Questions remain regarding the efficacy, safety, and neurodevelopmental impact of these therapies. Both preclinical and clinical data suggest troubling adverse drug reactions and the potential for adverse longterm neurodevelopmental impact. The negative impacts of standard pharmacologic agents suggest that alternative agents should be investigated. Dexmedetomidine is a promising alternative therapy that requires further interprofessional and multidisciplinary research in this population.

[Dexmedetomidine and clonidine: a review of their pharmacodynamy to define their role for sedation in intensive care patients]

Alpha-2 adrenergic agonists ("alpha-2 agonists") present multiple pharmacodynamic effects: rousable sedation, decreased incidence of delirium in the setting of critical care, preservation of respiratory drive, decreased whole body oxygen consumption, decreased systemic and pulmonary arterial impedance, improved left ventricular systolic and diastolic function, preserved vascular reactivity to exogenous catecholamines, preserved vasomotor baroreflex with lowered set point, preserved kidney function, decreased protein catabolism. These pharmacodynamic effects explain the interest for these drugs in the critical care setting. However, their exact role for sedation in critically ill-patients remains open for further studies. Given the few double-blind randomized multicentric trials available, the present non exhaustive analysis of the literature aims at presenting the utilization of alpha-2 agonists as potential first-line sedative agents, in the critical care setting. Suggestions regarding the use of alpha-2 agonists as sedatives are detailed.

Occurrence and predictors of dexmedetomidine infusion intolerance and failure

BACKGROUND

Dexmedetomidine, a selective α2 adrenergic receptor agonist, exhibits sedative, analgesic, anxiolytic, and sympatholytic effects, and may aid in controlling agitation in the intensive care unit (ICU). At our hospital (Barnes-Jewish Hospital, St. Louis, MO), dexmedetomidine is commonly used as a sedative in the medical ICU. Predictors of dexmedetomidine intolerance or failure have not yet been defined.

OBJECTIVE

Describe the rate of dexmedetomidine infusion intolerance/failure and identify patient predictors of intolerance/failure.

METHODS

This retrospective single-center cohort study evaluated 75 mechanically ventilated adults who received dexmedetomidine infusion. Patients were included in the study if they were aged ≥ 18 years; mechanically ventilated for > 24 hours; received dexmedetomidine infusion for ≥ 1 hour following > 24 hours of continuous infusions of midazolam, fentanyl, or propofol; and were admitted to our medical ICU between August 1, 2009 and August 1, 2010. Multivariate logistic regression analysis was performed to identify independent predictors of intolerance/failure.

RESULTS

A total of 85 episodes of dexmedetomidine infusion were analyzed (75 total patients). Eighteen episodes (21%) met the criteria for intolerance/failure and 67 episodes (79%) met the criteria for tolerance/success. The median duration of mechanical ventilation, total dexmedetomidine infusion time, and ICU length of stay did not differ between groups. Nonblack race was the only variable independently associated with treatment failure or intolerance in the logistic regression analysis.

CONCLUSION

Twenty-one percent of dexmedetomidine infusion episodes met the criteria for intolerance/failure. No predictors of intolerance/failure were found to be clinically significant.

Dexmedetomidine is effective for monitored anesthesia care in outpatients undergoing cataract surgery

BACKGROUND

Dexmedetomidine has a sedative analgesic property without respiratory depression. This study evaluated the efficacy of dexmedetomidine as an appropriate sedative drug for monitored anesthesia care (MAC) in outpatients undergoing cataract surgery on both eyes compared with combination of propofol and alfentanil.

METHODS

Thirty-one eligible patients were randomly divided into two groups on the first operation day. Dexmedetomidine was administered in group D at 0.6 µg/kg/h, and propofol and alfentanil was infused concomitantly in group P at a rate of 2 mg/kg/h and 20 µg/kg/h, respectively. Sedation was titrated at Ramsay sedation score 3. Iowa satisfaction with anesthesia scale (ISAS) of the patients was evaluated postoperatively. Systolic blood pressure (SBP), heart rate (HR), respiration rate (RR), and peripheral oxygen saturation (SpO(2)) were recorded throughout the surgery. For the second operation, the group assignments were exchanged.

RESULTS

Postoperative ISAS was 50.3 (6.2) in group D and 42.7 (8.7) in group P, which was statistically significant (P < 0.001). SBP was significantly lower in group D compared with group P from the beginning of the operation. HR, RR, and SpO(2) were comparable between the two groups. There were 8 cases (25.8%) of hypertension in group P, and 1 case (3.2%) in group D (P < 0.05). In contrast, 1 case (3.2%) of hypotension and 1 case (3.2%) of bradycardia occurred in group D.

CONCLUSIONS

Compared with the combined use of propofol and alfentanil, dexmedetomidine could be used appropriately for MAC in cataract surgery with better satisfaction from the patients and a more stable cardiovascular state.

Sedation with dexmedetomidine in the intensive care setting

Dexmedetomidine is an α-2 agonist that produces sedation and analgesia without compromising the respiratory drive. Use of dexmedetomidine as a sedative in the critically ill is associated with fewer opioid requirements compared with propofol and a similar time at goal sedation compared with benzodiazepines. Dexmedetomidine may produce negative hemodynamic effects including lower mean heart rates and potentially more bradycardia than other sedatives used in the critically ill. Recent studies have demonstrated that dexmedetomidine is safe at higher dosages, but more studies are needed to determine whether the efficacy of dexmedetomidine is dose dependent. In addition, further research is required to define dexmedetomidine’s role in the care of delirious critically ill patients, as many, but not all, studies have indicated favorable outcomes.