Evaluation of Dexmedetomidine's Effect on Temperature in Obese Critically Ill Patients

Introduction: Previous literature showed an association between hyperthermia and dexmedetomidine (DEX) use for ongoing sedation in non-obese patients. The purpose of this study is to evaluate DEX's effect on temperature in obese critically ill patients. Methods: This single center, retrospective, cohort study included patients ≥18 years, admitted to a surgical or medical ICU, received DEX for ≥8 hours as a single continuous infusion sedative, and weighed ≥120% of ideal body weight. Patients were excluded if they had a fever (≥38°C) and positive cultures within 48 hours of DEX initiation. The primary endpoint was a fever (Tmax of ≥38°C) within 48 hours of DEX initiation. Results: A total of 186 patients were included for evaluation. Forty-two patients (22.5%) had a fever during the first 48 hours of DEX initiation. Median weight was not different between the febrile and afebrile groups (99.4 [90.6-122.4] vs 97.6 [81.6-114.2] kg, P = .6). Median change from baseline temperature for all patients within 48 hours was an increase of .5 (.1-.8) °C, P < .001. In multiple regression analysis, duration of DEX and baseline temperature were the only significant predictors of fever development with an adjusted odds ratio of 1.041 (95% CI 1.009-1.074, P = .012) and 7.058 (95% CI 3.307-15.064, P < .001), respectively. Conclusions: This study suggests that there is a significant increase in body temperature from baseline for obese patients on DEX. Duration of DEX and baseline temperature were found to be risk factors for fever development in this population. Further studies are warranted.

Effects of intranasal and intramuscular dexmedetomidine in cats receiving total intravenous propofol anesthesia

Background and Aim:

The efficacy of intranasal (IN) dexmedetomidine in cats as a premedication remains elusive. Thus, this study aimed to compare the perioperative and sparing effects of IN and intramuscular (IM) dexmedetomidine administration on propofol requirements for anesthetic induction in cats.

Materials and Methods:

This study randomly assigned 16 cats into two groups of IN or IM dexmedetomidine at 20 μg/kg. Sedation scores and side effects were recorded at time points of 0, 5, 10, 15, and 20 min after the dexmedetomidine administration. Anesthesia was induced with intravenous (IV) 1% propofol by titrating a bolus of 2 mg every 45 s and the total dose of the administered IV propofol to achieve endotracheal intubation was recorded.

Results:

Cats receiving IM dexmedetomidine were significantly associated with higher sedation scores. All cats were sedated at 20 min after premedication; however, the average composite sedation scores in the IN group were significantly lower than those in the IM group during premedication. Pre-operative side effects, including vomiting, were more frequently observed in the IN group (5 cats, 62.5%) than in the IM group (3 cats, 37.5%; p < 0.05). Higher body temperature (>1°F compared to baseline) was more frequently observed in the IN group (6 cats, 75.0%) than in the IM group (1 cat, 12.5%; p < 0.05). The dosage of required propofol in the IN group was significantly higher (1.1 ± 0.3 mg/kg) than that in the IM group (0.7 ± 0.2 mg/kg; p < 0.05). The duration of general anesthesia was comparable between the groups.

Conclusion:

IN dexmedetomidine produces moderate sedation and cats may have side effects, including vomiting and higher body temperature. Higher sparing effects of propofol were identified in the IM group compared with the IN group. Nonetheless, IN administration of dexmedetomidine provides a noninvasive alternative to the IM route.

More than Drug Fever: Dexmedetomidine-Induced Hyperthermia in a Critically Ill Patient

Dexmedetomidine is a selective alpha-2 adrenergic agonist utilized for sedation in critically ill patients.¹ We present the case of a morbidly obese critically ill patient who experienced profound hyperthermia, with a maximum temperature of 41.4°C, hours after starting a dexmedetomidine infusion that was otherwise not explained by her clinical diagnoses. The hyperthermia resolved hours following cessation of the infusion. Dexmedetomidine was assessed as probable in terms of causing this adverse effect. Dexmedetomidine may be associated not only with low-grade fever, but as demonstrated in our case, it may be associated with significant temperature elevations requiring cessation of therapy to restore normothermia.

A Retrospective Characterization of Dexmedetomidine-Suspected Fever and Its Consequences in Adult Critically Ill Patients

Background:

Current evidence for dexmedetomidine-suspected fever (DSF) is limited. Lack of recognition may lead to costly or potentially harmful interventions for critically ill patients.

Objective:

The primary objective was to characterize escalations of care related to DSF. Secondary objectives were to describe the incidence, severity, and consequences associated with DSF.

Methods:

A retrospective review was conducted in critically ill adults who developed fever ≥39°C within 12 h from initiation of dexmedetomidine, with resolution of fever to <39°C within 12 h after discontinuation. The primary outcome was percentage of patients who received an escalation of care due to fever. Secondary outcomes included the percentage of patients who developed a multidrug-resistant organism or Clostridium difficile infection.

Results:

Eighteen of 3943 patients screened in 4099 encounters met criteria for DSF (0.4%). The majority were white (83.3%), male (66.7%), and underwent cardiac surgery (61.1%). Median (interquartile range [IQR]) time to fever onset and resolution were 5.5 (3.6-7.6) and 1.3 (1.0-2.9) h. Nine patients (50%) underwent infectious workup including antimicrobial initiation (n = 1, 5.6%), broadening of antimicrobials (n = 4, 22.2%), or culture collection (n = 9, 50%). Eleven patients (61.1%) underwent attempted temperature reduction. Twelve patients (66.7%) underwent diagnostic imaging. Incidence of multidrug-resistant organism and C. difficile infection were low (11.1 and 16.7% of fever patients, respectively).

Conclusion and Relevance:

Incidence of DSF was low and more common in cardiac surgery patients. Unrecognized DSF led to an escalation of care in most patients. Dexmedetomidine exposure should be considered as a potential cause of fever in critically ill adults.

Evaluation of dexmedetomidine anesthesia-related temperature changes: preliminary retrospective observational study

INTRODUCTION AND OBJECTIVE

Dexmedetomidine is a potent adrenergic alpha-2 agonist, and analgesic, sedative, anxiolytic and sympatholytic. Given there have been reports of dexmedetomidine associated temperature changes, in which these events have been associated with complications, our objective was to describe both temperature increase and decrease, during the intra and postoperative period (initial 24 hours), and factors associated, in patients who received dexmedetomidine for anesthesia/sedation in the surgical suite.

METHOD

Retrospective observational study, analyzing charts of patients ≥ 18 years submitted to anesthesia/sedation with dexmedetomidine, between 1/1/2017 and 31/12/2017. Upper temperature threshold was considered ≥ 37.8 °C, and lower, < 35 °C. The association with dexmedetomidine was assessed by the OMS/UMC causality system and by the Naranjo algorithm.

RESULTS

The sample included 42 patients who received dexmedetomidine and whose temperature data were available, with predominance of men 26 (62%), 49.4/16.5 years old (mean/standard deviation), and weight 65/35.8 kg. None of the patients presented intraoperative temperature equal to or above 37.8 °C or below 35 °C. During the postoperative period, one patient presented an increase ≥ 37.8 °C (2.4%) and three, temperature decrease < 35 °C (7%). Surgery/anesthesia time and exposure time to dexmedetomidine were not appropriate linear predictors of maximum temperature. Older age (p < 0.01), longer exposure to dexmedetomidine (p < 0.05) and shorter surgery time (p < 0.01) were significant linear predictors for lower minimum temperature.

CONCLUSIONS

Increase ≥ 37.8 °C/decrease < 35 °C of temperature possibly associated with dexmedetomidine did not occur in the intraoperative period and had a low frequency during the postoperative period.

Incidence of Fever Associated With Dexmedetomidine in the Adult Intensive Care Unit

BACKGROUND

Published literature has described the temporal relationship of dexmedetomidine with elevated temperatures, but there is limited data to quantify the incidence of fever in ICU patients receiving dexmedetomidine.

OBJECTIVE

The primary objective of this study was to estimate the incidence of temperature greater than or equal to 38.5°C in ICU patients receiving dexmedetomidine.

METHODS

This was a retrospective cohort study of ICU patients who received dexmedetomidine with a propensity-matched subgroup analysis comparing dexmedetomidine fever patients to non-fever patients. Patients 18 years of age and older admitted between November 2017 and August 2018 who received continuous dexmedetomidine for 6 or more hours were eligible for inclusion. Included patients with a temperature of great than or equal to 38.5°C while receiving dexmedetomidine were established as having dexmedetomidine-related fever.

RESULTS

Of 882 eligible ICU patients, 404 dexmedetomidine patients were included in the study. Sixty-one patients (15.1%) met the definition for the primary endpoint. Forty-two patients who received dexmedetomidine but experienced no fever were matched for multivariate analysis. The fever group received a higher mean maximum infusion rate (0.98 µg/kg/h ± 0.43 vs. 0.68 µg/kg/h ± 0.42, P < 0.001) and a longer median duration of dexmedetomidine (43.0 hours [range 7-711] vs. 24.3 hours [6-148], P = 0.001) compared to the non-fever group.

CONCLUSION

Fever greater than 38.5°C was observed in 15.1% of ICU patients while receiving dexmedetomidine. Prospective studies are warranted to validate these findings.

Fever Associated With Dexmedetomidine in Adult Acute Care Patients: A Systematic Review of the Literature

Dexmedetomidine-associated fever has been reported in the literature and can lead to lengthy workups and unnecessary antibiotic exposure. We conducted a systematic review to evaluate and describe the evidence of fever or hyperthermia caused by dexmedetomidine in adult patients. Data sources included PubMed/MEDLINE, EMBASE, CINAHL, and Web of Sciences. English-language studies of any design published from inception through April 2020 including conference abstracts were included. The target population was hospitalized adult patients. Quality of evidence was determined based on GRADE recommendations and risk of bias assessed using the Evidence Project Risk of Bias tool. Naranjo scores were assessed to determine the likeliness of adverse event being caused by dexmedetomidine. All data were extracted independently and with the guidance of a medical librarian. Four hundred and eighty-eight total citations were found on formal search, with 329 left after removal of duplicates. Independent record screening was performed, leaving 17 citations including 4 retrospective cohort studies, 1 case series, and 12 case reports. Quality of evidence ranged from very low to low for identified analyses. Evidence with patient-level data (case reports and series) were combined to establish a cohort for descriptive results. The median Naranjo score was 4 (range, 3 to 8), and dexmedetomidine doses ranged from 0.1 to 2 μg·h/kg. Obesity and cardiac surgery appear to be significant risk factors. Dexmedetomidine-associated fever appears uncommon, but the true incidence is unknown. Clinicians should keep dexmedetomidine-associated fever in their differential, and stewardship programs should consider assessing for this adverse effect in their patient monitoring.

The Effect of Early Sedation With Dexmedetomidine on Body Temperature in Critically Ill Patients

OBJECTIVES

Previous case series reported an association between dexmedetomidine use and hyperthermia. Temperature data have not been systematically reported in previous randomized controlled trials evaluating dexmedetomidine. A causal link between dexmedetomidine administration and elevated temperature has not been demonstrated.

DESIGN

Post hoc analysis.

SETTING

Four ICUs in Australia and New Zealand.

PATIENTS

About 703 mechanically ventilated ICU patients.

INTERVENTIONS

Early sedation with dexmedetomidine versus usual care.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was mean daily body temperature. Secondary outcomes included the proportions of patients with body temperatures greater than or equal to 38.3°C and greater than or equal to 39°C, respectively. Outcomes were recorded for 5 days postrandomization in the ICU. The mean daily temperature was not different between the dexmedetomidine (n = 351) and usual care (n = 352) groups (36.84°C ± sd vs 36.78°C ± sd; p = 0.16). Over the first 5 ICU days, more dexmedetomidine group (vs usual care) patients had a temperature greater than or equal to 38.3°C (43.3% vs 32.7%, p = 0.004; absolute difference 10.6 percentage points) and greater than or equal to 39.0°C (19.4% vs 12.5%, p = 0.013; absolute difference 6.9 percentage points). Results were similar after adjusting for diagnosis, admitting temperature, age, weight, study site, sepsis occurrence, and the time from dexmedetomidine initiation to first hyperthermia recorded. There was a significant dose response relationship with temperature increasing by 0.30°C ±0.08 for every additional 1 μg/kg/hr of dexmedetomidine received p < 0.0002.

CONCLUSIONS

Our study suggests potentially important elevations in body temperature are associated with early dexmedetomidine sedation, in adults who are mechanically ventilated in the ICU.

Impact of Dexmedetomidine on Tourniquet-Induced Systemic Effects in Total Knee Arthroplasty under Spinal Anesthesia: a Prospective Randomized, Double-Blinded Study

Background

Clinical studies on the impact of dexmedetomidine on tourniquet-induced systemic effects have been inconsistent. We investigated the impact of dexmedetomidine on tourniquet-induced systemic effects in total knee arthroplasty.

Methods

Eighty patients were randomly assigned to either control (CON) or dexmedetomidine (DEX) group. The DEX group received an intravenous loading dose of 0.5 μg/kg DEX over 10 minutes, followed by a continuous infusion of 0.5 μg/kg/h from 10 minutes before the start of surgery until completion. The CON group received the same calculated volume of normal saline. Pain outcomes and metabolic and coagulative changes after tourniquet application and after tourniquet release were investigated.

Results

The frequency of fentanyl administration postoperatively, patient-controlled analgesia (PCA) volume at 24 hours postoperatively, total PCA volume consumed in 48 hours postoperatively, and VAS score for pain at 24 and 48 hours postoperatively were significantly lower in the DEX group than in the CON group. Ten minutes after the tourniquet release, the DEX group showed significantly higher pH and lower lactate level than those in the CON group. Antithrombin III activity and body temperature 10 minutes after tourniquet release were significantly lower in the DEX group than in the CON group. Ca²⁺, K⁺, HCO₃ ^-, base excess, and PCO₂ levels 10 minutes after tourniquet release were not significantly different between the two groups.

Conclusion

We showed that DEX attenuated pain and hemodynamic, metabolic, and coagulative effects induced by the tourniquet. However, these metabolic and coagulative changes were within normal limits. Therefore, DEX could be used as an analgesic adjuvant, but should not be considered for routine use to prevent the systemic effects induced by tourniquet use.

Dexmedetomidine-Associated Hyperpyrexia in Three Critically Ill Patients With Coronavirus Disease 2019

Objectives:

To present three patients with severe coronavirus disease 2019 infection who developed life-threatening hyperpyrexia while being treated with dexmedetomidine for sedation.

Data Sources:

Clinical records.

Study Selection:

Case report.

Data Extraction:

Relevant clinical information.

Data Synthesis:

We describe three patients, a 60-year-old female, 43-year-old female, and 46-year-old male, who were hospitalized in surge ICUs during the coronavirus disease 2019 pandemic in the early spring of 2020. All developed hyperpyrexia, defined as a temperature above 41.1°C, following an increase in dexmedetomidine dosing to above 1.5 µg/kg/hr. Fevers resolved following discontinuation of dexmedetomidine.

Conclusions:

While the exact mechanism of hyperpyrexia remains unclear, findings in this study suggest that high doses of dexmedetomidine infusion are associated with hyperpyrexia in a seemingly dose-dependent fashion in critically ill patients with coronavirus disease 2019. Coronavirus disease 2019 infection causes a hyperinflammatory state characterized by pro-inflammatory cytokine dysregulation. Dexmedetomidine, a centrally acting alpha-2 agonist, may alter hypothalamic temperature regulation through disturbances in neurotransmitter expression and metabolism. We postulate that the use of high-dose dexmedetomidine in a hyperinflammatory state may increase the risk of developing hyperpyrexia in this severe disease state.