Dexmedetomidine premedication increases preoperative sedation and inhibits stress induced by tracheal intubation in adult: a prospective randomized double-blind clinical study

Effect of Transcutaneous Electrical Acupoint Stimulation on Extubation-Related Stress Response in Noncardiac Surgery Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

PURPOSE

Stress response is a common complication during extubation, mainly manifested by dramatic hemodynamic fluctuations. Transcutaneous electrical acupoint stimulation (TEAS) is widely applied in the perioperative period. We performed this meta-analysis to evaluate whether the TEAS could relieve the stress response during extubation in noncardiac surgery patients.

DESIGN

A systematic review and meta-analysis of randomized controlled trials.

METHODS

We searched six databases (PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, CNKI, and Wan Fang) for relevant literature. A risk of bias assessment was executed based on the Cochrane Criteria. We applied RevMan5.4.1 software to analyze data. When the χ2 test did not show heterogeneity, we adopted the fixed-effect model. Otherwise, the random-effect model was used.

FINDINGS

ln total, 12 randomized controlled trials with 1,347 participants were enrolled in this meta-analysis. Meta-analysis showed the heart rate and mean arterial pressure of the intervention group were significantly lower than the control group at immediately, 5 minutes, and 10 minutes after extubation. The occurrence rate of emergency agitation (RR 0.39, 95% CI [0.26,0.60]) and postoperative delirium (RR 0.40, 95% CI [0.22, 0.72] were also lower in the TEAS group. The consumption of propofol (standardized mean difference (SMD) 0.47, 95% CI [-0.77, -0.18]) and remifentanil (SMD 1.49, 95% CI [-2.01, -0.96]) of the intervention group were also significantly reduced compared with the control group.

CONCLUSIONS

TEAS was beneficial for improving stress response during extubation, emergence agitation, postoperative delirium, and reduced the consumption of intraoperative propofol and remifentanil, but it was necessary to note the limitations of the current evidence.

Effects and mechanisms of perioperative medications on the hypothalamic pituitary adrenal response to surgical injury: A narrative review

The adrenal gland is a vital endocrine organ, and adrenal steroid synthesis and secretion are closely regulated by the hypothalamic-pituitary-adrenal (HPA) axis in response to various stimuli. Surgery or trauma can activate the HPA axis and induce the secretion of cortisol. Different cortisol responses vary with the grade of surgery. Perioperative medications have the potential to decrease the cortisol level in the body, and both excessive and insufficient cortisol levels after surgery are disadvantageous. The effect of perioperative medications on the HPA response to surgery can be divided into three levels: "adrenal insufficiency (AI)", "stress response inhibition", and "uncertainty". The clinical presentation of AI includes fatigue, nausea, vomiting, abdominal pain, muscle cramps, hypotension, hypovolemic shock and prerenal failure, which may result in fatal consequences. Stress response inhibition can reduce postoperative complications, such as pain and cognitive dysfunction. This is protective to patients during perioperative and postoperative periods. The aim of the present review is to shed light on current evidence regarding the exact effects and mechanisms of perioperative medications on the HPA response to surgical injury and provide the applicable guidance on clinical anesthesia.

Dexmedetomidine Inhibits Paraventricular Corticotropin-releasing Hormone Neurons that Attenuate Acute Stress-induced Anxiety-like Behavior in Mice

BACKGROUND

Dexmedetomidine has repeatedly shown to improve anxiety, but the precise neural mechanisms underlying this effect remain incompletely understood. This study aims to explore the role of corticotropin-releasing hormone-producing hypothalamic paraventricular nucleus (CRHPVN) neurons in mediating the anxiolytic effects of dexmedetomidine.

METHODS

A social defeat stress mouse model was used to evaluate the anxiolytic effects induced by dexmedetomidine through the elevated plus maze, open-field test, and measurement of serum stress hormone levels. In vivo Ca2+ signal fiber photometry and ex vivo patch-clamp recordings were used to determine the excitability of CRHPVN neurons and investigate the specific mechanism involved. CRHPVN neuron modulation was achieved through chemogenetic activation or inhibition.

RESULTS

Compared with saline, dexmedetomidine (40 µg/kg) alleviated anxiety-like behaviors. Additionally, dexmedetomidine reduced CRHPVN neuronal excitability. Chemogenetic activation of CRHPVN neurons decreased the time spent in the open arms of the elevated plus maze and in the central area of the open-field test. Conversely, chemogenetic inhibition of CRHPVN neurons had the opposite effect. Moreover, the suppressive impact of dexmedetomidine on CRHPVN neurons was attenuated by the α2-receptor antagonist yohimbine.

CONCLUSIONS

The results indicate that the anxiety-like effects of dexmedetomidine are mediated via α2-adrenergic receptor-triggered inhibition of CRHPVN neuronal excitability in the hypothalamus.

EDITOR’S PERSPECTIVE

The Surgical Stress Response and Anesthesia: A Narrative Review

The human physiological response "to stress" includes all metabolic and hormonal changes produced by a traumatic event at the micro or macro cellular levels. The main goal of the body's first response to trauma is to keep physiological homeostasis. The perioperative non-specific adaptation response can sometimes be detrimental and can produce systemic inflammatory response syndrome (SIRS), characterized by hypermetabolism and hyper catabolism. We performed a narrative review consisting of a description of the surgical stress response's categories of changes (neurohormonal and immunological response) followed by reviewing methods found in published studies to modulate the surgical stress response perioperatively. We described various preoperative measures cited in the literature as lowering the burden of surgical trauma. This article revises the anesthetic drugs and techniques that have an impact on the surgical stress response and proven immune-modulatory effects. We also tried to name present knowledge gaps requiring future research. Our review concludes that proper preoperative measures, adequate general anesthetics, multimodal analgesia, early postoperative mobilization, and early enteral nutrition can decrease the stress response to surgery and ease patient recovery. Anesthetics and analgesics used during the perioperative period may modulate the innate and adaptive immune system and inflammatory system, with a consecutive impact on cancer recurrence and long-term outcomes.

Alpha-2-adrenergic agonists reduce resting energy expenditure in humans during external cooling

Intravenous alpha-2-adrenergic receptor agonists reduce energy expenditure and lower the temperature when shivering begins in humans, allowing a decrease in core body temperature. Because there are few data about similar effects from oral drugs, we tested whether single oral doses of the sedative dexmedetomidine (1 µg/kg sublingual or 4 µg/kg swallowed) or the muscle relaxant tizanidine (8 mg or 16 mg), combined with surface cooling, reduce energy expenditure and core body temperature in humans. A total of 26 healthy participants completed 41 one-day laboratory studies measuring core body temperature using an ingested telemetry capsule and measuring energy expenditure using indirect calorimetry for up to 6 hours after drug ingestion. Dexmedetomidine induced a median 13% - 19% peak reduction and tizanidine induced a median 15% - 22% peak reduction in energy expenditure relative to baseline. Core body temperature decreased a median of 0.5°C - 0.6°C and 0.5°C - 0.7°C respectively. Decreases in temperature occurred after peak reductions in energy expenditure. Energy expenditure increased with a decrease in core temperature in control participants but did not occur after 4 µg/kg dexmedetomidine or 16 mg tizanidine. Plasma levels of dexmedetomidine but not tizanidine were related to mean temperature change. Decreases in heart rate, blood pressure, respiratory rate, cardiac stroke volume index, and cardiac index were associated with the change in metabolic rate after higher drug doses. We conclude that both oral dexmedetomidine and oral tizanidine reduce energy expenditure and allow decrease in core temperature in humans.

Low-dose intranasal dexmedetomidine premedication improves epidural labor analgesia onset and reduces procedural pain on epidural puncture: a prospective randomized double-blind clinical study

BACKGROUND

Epidural labor analgesia is a safe and effective method of pain management during labor with the drawbacks of delayed onset and maternal distress during epidural puncture. This study aimed to determine whether pretreatment with intranasal low-dose dexmedetomidine effectively shortens the onset of analgesia and reduces procedural pain.

METHODS

In this prospective, randomized double-blind trial, nulliparous patients were randomly assigned to either the intranasal dexmedetomidine group or the control group. The intranasal dexmedetomidine group received 0.5 μg/kg dexmedetomidine intranasally, and the control group received an equal volume of normal saline intranasally. Both groups were maintained with a programmed intermittent epidural bolus. The primary outcome was the onset time of analgesia and scores of pain related to the epidural puncture.

RESULTS

Seventy-nine patients were enrolled, and 60 completed the study and were included in the analysis. The time to achieve adequate analgesia was significantly shorter in the intranasal dexmedetomidine group than in the control group (hazard ratio = 2.069; 95% CI, 2.187 to 3.606; P = 0.010). The visual analogue scale pain scores during epidural puncture in the intranasal dexmedetomidine group were also significantly lower than those in the control group (2.0 (1.8-2.5) vs. 3.5 (3.3-4.5), P ≤ 0.001, Table 2). Pretreatment with intranasal dexmedetomidine before epidural labor analgesia was associated with improved visual analogue scale pain scores and Ramsay scores, less consumption of analgesics and higher maternal satisfaction (P < 0.05). No differences were observed for labor and neonatal outcomes or the incidence of adverse effects between the two groups.

CONCLUSIONS

Pretreatment with intranasal dexmedetomidine before epidural labor analgesia yielded a faster onset of analgesia and decreased epidural puncture pain without increasing adverse effects. Pretreatment with intranasal dexmedetomidine may be a useful adjunct for the initiation of epidural analgesia, and further investigation should be encouraged to determine its utility more fully.

TRIAL REGISTRATION

This trial was prospectively registered at Chictr.org.cn on 29/05/2020 with the registration number ChiCTR2000033356 ( http://www.chictr.org.cn/listbycreater.aspx ).