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.

Application of intranasal dexmedetomidine in magnetic resonance imaging of preterm infants: The ED50, efficacy and safety analysis

BACKGROUND

Infants undergoing magnetic resonance imaging (MRI) often require pharmacological sedation. Dexmedetomidine serves as a novel sedative agent that induces a unique unconsciousness similar to natural sleep, and therefore has currently been used as the first choice for sedation in infants and young children.

OBJECTIVE

To determine the 50% effective dose (ED50) and 95% confidence interval (95%CI) of intranasal dexmedetomidine for MRI in preterm and term infants, and to observe the incidence of adverse events. To explore whether there were differences in ED50 and 95%CI, heart rate (HR) and blood oxygen saturation (SpO2), the induction time and wake-up time and the incidence of adverse events between the 2 groups, so as to provide guidance for clinical safe medication for the meanwhile.

METHODS

A total of 68 infants were prospectively recruited for MRI examination under drug sedation (1 week ≤ age ≤ 23 weeks or weight ≤ 5kg). The children were divided into 2 groups according to whether they had preterm birth experience (Preterm group, Atterm group). The Dixon up-and-down method was used to explore ED50. The basic vital signs of the 2 groups were recorded, and the heart rate and SpO2 were recorded every 5 minutes until the infants were discharged from the hospital. The induction time, wake-up time and adverse events were recorded.

RESULTS

The ED50 (95%CI) of intranasal dexmedetomidine in the Preterm group and the Atterm group were 2.23 (2.03-2.66) μg/kg and 2.64 (2.49-2.83) μg/kg, respectively (P < .05). the wake-up time was longer in Preterm group (98.00min) than in Atterm group (81.00 min) (P < .05), the incidence of bradycardia in Preterm group was 3/33, which was higher than that in Atterm group (1/35). There was no difference in the induction time between the 2 groups (P > .05), and there was no significant difference in other adverse events.

CONCLUSIONS

Intranasal dexmedetomidine can be safely used for sedation in preterm infants undergoing MRI. Compared with term infants, preterm infants have a lower dose of dexmedetomidine, a higher incidence of bradycardia, and a longer weak-up time.

Trends and patterns in the practice of pediatric sedation for magnetic resonance imaging in Japan: A longitudinal descriptive study from 2012 to 2019

BACKGROUND

Worldwide, pediatric sedation for magnetic resonance imaging is a standard practice; however, there are few studies on its trends and patterns.

AIMS

This study aimed to investigate the trends and patterns of pediatric sedation for magnetic resonance imaging in Japan and determine the incidence of and risk factors for adverse events/interventions.

METHODS

This longitudinal descriptive study assessed children (age < 15 years) who underwent sedation for magnetic resonance imaging between April 2012 and December 2019 in Japan using a nationwide claims database. We assessed the patients' demographic characteristics, time trends in sedatives, sedative patterns by age, and adverse events/interventions within two post-sedation days. Further, we used multivariable logistic regression models to explore factors related to the incidence of adverse events/interventions.

RESULTS

We identified 29 187 cases (median age, 2.0 years; 55.2% males). The most common sedative was triclofos sodium (n = 18 812, 51.7%). There was an increasing trend in barbiturate use (17.0% [2012] to 25.0% [2019]) and decreasing trends in the use of triclofos sodium (56.4% [2012] to 47.7% [2019]) and chloral hydrate (15.6% [2012] to 10.8% [2019]). We identified 534 adverse events/interventions in 460 cases (1.5%). Multivariable logistic regression analyses revealed that the incidence of adverse events/interventions mainly increased with the number of sedatives (≥3; adjusted odds ratio, 5.10; 95% confidence interval, 3.67-7.10) and unscheduled setting (adjusted odds ratio, 6.28; 95% confidence interval, 4.85-8.61); further, it decreased with high hospital procedure volume (adjusted odds ratio, 0.62; 95% confidence interval, 0.49-0.78).

CONCLUSIONS

Based on a Japanese real-world setting, there is an increasing trend in barbiturate use and decreasing trends in the use of triclofos sodium and chloral hydrate in pediatric sedation for magnetic resonance imaging. Low hospital procedure volumes were associated with an increased risk of adverse events/interventions.

Magnetic resonance imaging quality control, quality assurance and quality improvement

Quality in MR imaging is a comprehensive process that encompasses scanner performance, clinical processes for efficient scanning and reporting, as well as data-driven improvement involving measurement of key performance indicators. In this paper, the authors review this entire process. This article provides a framework for establishing a successful MR quality program. The collective experiences of the authors across a spectrum of pediatric hospitals is summarized here.

Use of Intranasal Dexmedetomidine as a Solo Sedative for MRI of Infants

BACKGROUND

Dexmedetomidine, a selective α-2 receptor agonist, can be delivered via the intranasal (IN) route and be used for procedural sedation. The drug's favorable hemodynamic profile and relative ease of application make it a promising agent for sedation during radiologic procedures, although there are few studies on its efficacy for MRI studies.

METHODS

A retrospective chart review was performed between June 2014 and December 2016. Outpatients between 1 and 12 months of age who received 4 μg/kg of IN dexmedetomidine for MRI were included in the analysis. Our aim with this study was to determine the rate of successful completion of the sedation procedure without the need for a rescue drug (other than repeat IN dexmedetomidine).

RESULTS

A total of 52 subjects were included in our study. Median (interquartile range) patient age was 7 (5-8) months. Median (interquartile range) procedure length was 40 (35-50) minutes. Overall success rate (including first dose and any rescue dose IN) of dexmedetomidine was 96.2%. None of the patients had significant adverse effects related to dexmedetomidine.

CONCLUSIONS

IN dexmedetomidine is an effective solo sedative agent for MRI in infants.

Comparison of sedation by intranasal dexmedetomidine and oral chloral hydrate for pediatric ophthalmic examination

BACKGROUND AND AIM

Pediatric ophthalmic examinations can be conducted under sedation either by chloral hydrate or by dexmedetomidine. The objective was to compare the success rates and quality of ophthalmic examination of children sedated by intranasal dexmedetomidine vs oral chloral hydrate.

METHODS

One hundred and forty-one children aged from 3 to 36 months (5-15 kg) scheduled to ophthalmic examinations were randomly sedated by either intranasal dexmedetomidine (2 μg·kg^-1 , n = 71) or oral chloral hydrate (80 mg·kg^-1 , n = 70). The primary endpoint was successful sedation to complete the examinations including slit-lamp photography, tonometry, anterior segment analysis, and refractive error inspection. The secondary endpoints included quality of eye position, intraocular pressure, onset time, duration of examination, recovery time, discharge time, any side effects during examination, and within 48 h after discharge.

RESULTS

Sixty-one children were sedated by dexmedetomidine with a success rate of 85.9%, which is significantly higher than that by chloral hydrate (64.3%) [OR 3.39, 95% CI: 1.48-7.76, P = 0.003]. Furthermore, children in the dexmedetomidine group displayed better eye position in anterior segment analysis than in chloral hydrate group median difference. All children displayed stable hemodynamics and none suffered hypoxemia in both groups. Oral chloral hydrate induced higher percentages of vomiting and altered bowel habit after discharge than dexmedetomidine.

CONCLUSIONS

Intranasal dexmedetomidine provides more successful sedation and better quality of ophthalmic examinations than oral chloral hydrate for small children.

General anesthesia with a native airway for patients with mucopolysaccharidosis type III

BACKGROUND

Mucopolysaccharidosis type III is a progressive disease with worsening airway, pulmonary, and cardiac involvement that may complicate anesthetic care.

AIM

To prospectively evaluate the incidence of airway issues and complications during magnetic resonance imaging (MRI) and lumbar puncture (LP) during general anesthesia with a native airway for patients with mucopolysaccharidosis type III.

METHOD

The study was a part of the natural history study. Anesthesia was induced with sevoflurane, which was discontinued after intravenous access was obtained. General anesthesia with a native airway was provided by dexmedetomidine and propofol. Dexmedetomidine (0.5 μg·kg^-1 ) was administered over 5 min followed by a continuous infusion at 0.5 μg·kg^-1 ·h^-1 . A continuous infusion of propofol was started at 150 μg·kg^-1 ·min^-1 . A bolus dose of propofol (1 mg·kg^-1 ) was administered and the propofol infusion was increased as needed. Airway management and vital signs were recorded for the entire procedure until discharge.

RESULTS

Twenty-five patients (6.9 ± 3.1 years) received total of 43 MRI and LP procedures in the cohort. No patient failed sedation. Although mask induction with sevoflurane was not clinically problematic, upper airway obstruction was noted during 14 procedures (33%). This required the application of continuous positive airway pressure, temporary oral airway placement, jaw thrust, or shoulder roll. Airway dynamics improved once the anesthesia was transitioned to intravenous anesthetic agents. Although a small shoulder roll was needed to improve airway patency for 11 cases (26%), a large shoulder roll tended to make the upper airway obstruction worse. Oxygen desaturation (≤90%) was noted during MRI in three cases (7%).

CONCLUSION

A combination of dexmedetomidine and propofol provided effective general anesthesia with a native airway during the procedures. Although upper airway obstruction was noted, it resolved with simple airway maneuvers without further airway intervention.

Rescue Sedation With Intranasal Dexmedetomidine for Pediatric Ophthalmic Examination After Chloral Hydrate Failure: A Randomized, Controlled Trial

PURPOSE

It is a challenge to rescue ophthalmology examinations performed in children in the sedation room after initial chloral hydrate failure. Intranasal dexmedetomidine can be used in rescue sedation in children undergoing computed tomography. The present study aimed to assess the efficacy and tolerability of intranasal dexmedetomidine use in children undergoing ophthalmic examination after chloral hydrate failure.

METHODS

Sixty uncooperative pediatric patients with cataract (aged 5-36 months; weight, 7-15 kg) presented for follow-up ophthalmic examination. Patients who experienced chloral hydrate failure were randomized to 1 of 2 groups to receive intranasal dexmedetomidine 1 or 2 μg/kg for rescue sedation. Each group contained 30 patients. The primary outcome was the rate of a successful ophthalmic examination. Secondary outcomes included sedation onset time, recovery time, duration of examination, discharge time, and adverse events, including percentage of heart rate reduction, respiratory depression, vomiting, and postsedative agitation.

FINDINGS

A successful ophthalmic examination was achieved in 93.3% (28/30) of patients in the 2-μg/kg dose group and in 66.7% (20/30) of patients in the 1-μg/kg dose group (P = 0.021). The onset time, recovery time, and discharge time did not significantly differ between the 2 groups. None of the patients required clinical intervention due to heart rate reduction, and none of the patients in either group experienced vomiting, respiratory depression, or agitation after the administration of dexmedetomidine.

IMPLICATIONS

In children undergoing ophthalmic examination, intranasal dexmedetomidine can be administered in the sedation room for rescue sedation after chloral hydrate failure, with the 2-μg/kg dose being more efficacious than the 1-μg/kg dose, as measured by success rate. ClinicalTrials.gov identifier: NCT02077712.

Pediatric Chest MR Imaging: Sedation, Techniques, and Extracardiac Vessels

Thoracic MR imaging in the pediatric population provides unique challenges requiring tailored protocols and a practical approach to pediatric issues, such as patient motion and sedation. Concern regarding the use of ionizing radiation in the pediatric population has continued to advance the use of MR imaging despite these challenges. This article provides a practical approach to thoracic vascular MR imaging with special attention paid to pediatric-specific issues such as sedation. Thoracic vascular anatomy and pathology are discussed with an emphasis on protocols that can facilitate accurate diagnosis.

Preterm Versus Term Children: Analysis of Sedation/Anesthesia Adverse Events and Longitudinal Risk

BACKGROUND AND OBJECTIVES

Preterm and former preterm children frequently require sedation/anesthesia for diagnostic and therapeutic procedures. Our objective was to determine the age at which children who are born <37 weeks gestational age are no longer at increased risk for sedation/anesthesia adverse events. Our secondary objective was to describe the nature and incidence of adverse events.

METHODS

This is a prospective observational study of children receiving sedation/anesthesia for diagnostic and/or therapeutic procedures outside of the operating room by the Pediatric Sedation Research Consortium. A total of 57,227 patients 0 to 22 years of age were eligible for this study. All adverse events and descriptive terms were predefined. Logistic regression and locally weighted scatterplot regression were used for analysis.

RESULTS

Preterm and former preterm children had higher adverse event rates (14.7% vs 8.5%) compared with children born at term. Our analysis revealed a biphasic pattern for the development of adverse sedation/anesthesia events. Airway and respiratory adverse events were most commonly reported. MRI scans were the most commonly performed procedures in both categories of patients.

CONCLUSIONS

Patients born preterm are nearly twice as likely to develop sedation/anesthesia adverse events, and this risk continues up to 23 years of age. We recommend obtaining birth history during the formulation of an anesthetic/sedation plan, with heightened awareness that preterm and former preterm children may be at increased risk. Further prospective studies focusing on the etiology and prevention of adverse events in former preterm patients are warranted.

High-dose dexmedetomidine for noninvasive pediatric procedural sedation and discharge readiness

BACKGROUND

The University of North Carolina's (UNC) Pediatric Sedation Service adopted a noninvasive procedural sedation protocol that uses dexmedetomidine in children based on review of literature that reported fast recovery times and low morbidity. This study aimed to compare dexmedetomidine discharge readiness times observed at UNC with those previously published with a hypothesis that the discharge times at UNC are longer than those previously published. A secondary aim was to evaluate the safety profile of the protocol.

METHODS

Pediatric outpatients (6 months-18 years) who received dexmedetomidine per protocol for a noninvasive procedure or study from January 2011 through April 2012 were included in this retrospective chart review. A total of 615 patient encounters were evaluated. Patients received bolus doses of 2 μg·kg(-1) over 10 min for up to three doses followed by a 1 μg·kg(-1) ·h(-1) infusion (group 1) or a 1.5 μg·kg(-1) ·h(-1) infusion (group 2). Primary outcomes included time to sedation, time to arousal, and time to discharge.

RESULTS

No significant differences between the dosing groups were noted. Time to discharge was significantly shorter for group 1 (79 min) than for group 2 (101 min). The range of discharge times at UNC was 78.7-100.9 min compared to previous studies that report recovery times of 24.8-35.2 min.

CONCLUSION

Dexmedetomidine arousal and discharge times observed at UNC were longer than anticipated when compared to literature. The safety profile of the drug was comparable to prior studies.

Provision of deep procedural sedation by a pediatric sedation team at a freestanding imaging center

BACKGROUND

Freestanding imaging centers are popular options for health care systems to offer services accessible to local communities. The provision of deep sedation at these centers could allow for flexibility in scheduling imaging for pediatric patients. Our Children's Sedation Services group, comprised of pediatric critical care medicine and pediatric emergency medicine physicians, has supplied such a service for 5 years. However, limited description of such off-site services exists. The site has resuscitation equipment and medications, yet limited staffing and no proximity to hospital support.

OBJECTIVE

To describe the experience of a cohort of pediatric patients undergoing sedation at a freestanding imaging center.

MATERIALS AND METHODS

A retrospective chart review of all sedations from January 2012 to December 2012. Study variables include general demographics, length of sedation, type of imaging, medications used, completion of imaging, adverse events based on those defined by the Pediatric Sedation Research Consortium database and need for transfer to a hospital for additional care.

RESULTS

Six hundred fifty-four consecutive sedations were analyzed. Most patients were low acuity American Society of Anesthesiologists physical class ≤ 2 (91.8%). Mean sedation time was 55 min (SD ± 24). The overwhelming majority of patients (95.7%) were sedated for MRI, 3.8% for CT and <1% (three patients) for both modalities. Propofol was used in 98% of cases. Overall, 267 events requiring intervention occurred in 164 patient encounters (25.1%). However, after adjustment for changes from expected physiological response to the sedative, the rate of events was 10.2%. Seventy-five (11.5%) patients had desaturation requiring supplemental oxygen, nasopharyngeal tube or oral airway placement, continuous positive airway pressure or brief bag valve mask ventilation. Eleven (1.7%) had apnea requiring continuous positive airway pressure or bag valve mask ventilation briefly. One patient had bradycardia that resolved with nasopharyngeal tube placement and continuous positive airway pressure. Fifteen (2.3%) patients had hypotension requiring adjustment of the sedation drip but no fluid bolus. Overall, there were six failed sedations (0.9%), defined by the inability to complete the imaging study. There were no serious adverse events. There were no episodes of cardiac arrest or need for intubation. No patient required transfer to a hospital.

CONCLUSION

Sedation provided at this freestanding imaging center resulted in no serious adverse events and few failed sedations. While this represents a limited cohort with sedations performed by predominately pediatric critical care medicine and pediatric emergency medicine physicians, these findings have implications for the design and potential scope of practice of outpatient pediatric sedation services to support community-based pediatric imaging.

Dexmedetomidine infusion associated with transient adrenal insufficiency in a pediatric patient: a case report

Dexmedetomidine is a highly selective α₂-adrenoceptor agonist used for sedation due to its anxiolytic and analgesic properties without respiratory compromise. Due to its structural similarity to etomidate, there has been concern that dexmedetomidine may cause adrenal insufficiency. This concern was initially supported by animal studies, but subsequent human studies demonstrated mixed results. We describe the case of transient adrenal insufficiency in a 1-year-old male who presented with 24% total body surface 2nd degree burns. He required sedation with a prolonged, high-dose dexmedetomidine infusion with a peak infusion dose of 2.7 mcg/kg/hr and duration of 6.5 days. The patient developed lethargy and hypotension four days after discontinuation of his infusion. He had a random cortisol level which was low at 0.4 mcg/dL, and the concern for adrenal suppression was confirmed with an ACTH stimulation test with the baseline cortisol of 0.4 mcg/dL and inappropriate 60 minute post-ACTH stimulation cortisol of 7.8 mcg/dL. While further studies will be needed to clarify the risk of adrenal suppression secondary to dexmedetomidine, this case suggests that caution should be taken when administering dexmedetomidine to pediatric patients and highlights the need for future studies to look at appropriate dosing and duration of dexmedetomidine infusions.