Cardiovascular Effects of Dexmedetomidine Sedation in Children

Optimal doses of intranasal esketamine plus dexmedetomidine for sedating toddlers during transthoracic echocardiography: a prospective, double-blind, randomized trial

INTRODUCTION

Esketamine has unique advantages in combination with dexmedetomidine for sedation in young children, owing to its sympathetic activity and mild respiratory depression. However, the optimal dose is yet to be determined. In this study, we compared the different doses of intranasal esketamine combined with dexmedetomidine for sedation during transthoracic echocardiography in toddlers.

PATIENTS AND METHODS

A total of 121 eligible children aged 13 years, who were scheduled for transthoracic echocardiography were randomized into three groups. They were treated with intranasal dexmedetomidine 1 mcg.kg-1 + esketamine 0.5 mg.kg-1 (group S1), dexmedetomidine 1 mcg.kg-1 + esketamine 1 mg.kg-1 (group S2), or dexmedetomidine 1 mcg.kg-1 + esketamine 1.5 mg.kg-1 (group S3). The primary outcome was the success rate of sedation, other outcomes included HR, SpO2, onset time, wake-up time, and adverse effects.

RESULTS

The success rate of sedation was significantly higher in groups S2 (85.4%) and S3 (87.5%) than ingroup S1 (60%) (p = 0.004). The baseline HR and SpO2 did not differ between the groups at the corresponding time points following drug administration. The onset time and duration of sedation in group S1 were significantly longer than those in groups S2 and S3 (p = 0.000). However, there were no differences in the wake-up time or adverse effects among the three groups.

CONCLUSIONS

Intranasal administration of 1 mg.kg-1 esketamine combined with 1 mcg.kg-1 dexmedetomidine provided satisfactory sedation in young children undergoing transthoracic echocardiography. This sedative approach offers a rapid onset of awakening with few side effects.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2200060976, 2022/06/14 (trail from August 2022 to January 2023).

Perioperative and Anesthetic Considerations in Shone's Complex

Shone's complex is a congenital cardiac disease consisting of the following four lesions: parachute mitral valve, supravalvar mitral ring, subaortic stenosis, and aortic coarctation. Though not all components are required for a diagnosis, the end result is both left ventricular inflow and outflow obstruction, which typically present in patients as congestive heart failure. The complex pathology requires careful management and surgical decision-making to ensure an optimal outcome. This review will focus on the anatomy, physiology, and perioperative anesthetic management of patients with Shone's complex.

Nalbuphine reduces the incidence of emergence agitation in children undergoing Adenotonsillectomy: A prospective, randomized, double-blind, multicenter study

OBJECTIVE

To evaluate the effect of nalbuphine on emergence agitation (EA) in children undergoing adenotonsillectomy.

DESIGN

Multicenter, prospective, double-blind, randomized controlled trial.

SETTING

The First People's Hospital of Foshan and three other participating institutions in China, from April 2020 to December 2021.

PATIENTS

Eight hundred patients, 3-9 years of age, American Society of Anesthesiologists (ASA) classification I or II, undergoing elective adenotonsillectomy were included.

INTERVENTIONS

Nalbuphine (0.1 mg/kg) or saline was administered intravenously.

MEASUREMENTS

The incidence of EA; the pediatric anesthesia emergence delirium (PAED) scale; and the faces, legs, activity, cry, and consolability (FLACC) scales. Extubation time, duration of post-anesthesia care unit (PACU) stay, anesthesia nurses' and parents' satisfaction, and other side effects.

MAIN RESULTS

The incidence of EA in the nalbuphine group was lower than that in the saline group 30 min after extubation (10.28% vs. 28.39%, P = 0.000). In addition, the FLACC scores in the nalbuphine group were lower than those in the saline group 30 min after extubation (P < 0.05). Furthermore, the proportion of moderate-to-severe pain cases (FLACC scores >3) was significantly lower in the nalbuphine group than in the saline group (33.58% vs. 60.05%, P = 0.000). Adjusting the imbalance of postoperative pain intensity, the risk of EA was still lower in the nalbuphine group at 0 min (OR, 0.39; 95% CI, 0.26-0.60; P = 0.000), (OR, odds ratio; CI, confidence interval), 10 min (OR, 0.39; 95% CI, 0.19-0.79; P = 0.01), and 20 min (OR, 0.27; 95% CI, 0.08-0.99; P = 0.046) than in the saline group. There were no significant differences in extubation time, duration of PACU stay, nausea and vomiting, or respiratory depression between the two groups (P > 0.05).

CONCLUSION

Nalbuphine reduced the incidence of EA in children after adenotonsillectomy under general anesthesia, which may be involved in both analgesic and non-analgesic pathways.

Awake Craniotomy for Cerebral Abscess with Pulmonary Arteriovenous Malformation

A cerebral abscess can be a life-threatening complication of pulmonary arteriovenous malformations (PAVM), thus posing significant morbidity if left untreated. We report a case of an incidental finding of a PAVM in a patient diagnosed with cerebral abscess. A 22-year-old male presented to the emergency department with acute onset right-sided weakness in both upper and lower limbs for 1 week. Magnetic resonance imaging showed a ring-enhancing lesion within the left parasagittal frontoparietal region s/o intracerebral abscess. High-resolution computed tomography was done as a protocol in patients posted for surgery due to coronavirus disease 2019 and coincidentally, it showed a single well-defined parenchymal nodule, 4 × 3.4 cm in the lateral basal segment of the left lower lobe. The knowledge of the pathophysiology of PAVM and expected complications during general anesthesia (GA) and positive pressure mechanical ventilation is essential. In such conditions, awake craniotomy under conscious sedation and scalp block may be considered as an alternative to GA.

Justification Of Empiric Methodology to Determine Dexmedetomidine Dose for the TREX Study

INTRODUCTION

Dexmedetomidine is the sedative agent administered in combination with remifentanil and low dose of sevoflurane in the interventional arm of the ongoing TREX trial (Trial Remifentanil DExmedetomidine). The TREX pilot study (published in Paediatr Anaesth 2019;29:59-67) established infusion rates higher than those initially proposed. This could be attributed to an inappropriate target concentration for sedation or incorrect initial pharmacokinetic parameter estimates.

METHODS

The TREX study is a Phase III, randomized, active controlled, parallel group, blinded evaluator, multicentre, superiority trial comparing neurological outcome after standard sevoflurane anaesthesia with dexmedetomidine/remifentanil and low dose sevoflurane anaesthesia in children aged less than 2 years undergoing anaesthesia of 2 hours or longer. In this report, dexmedetomidine pharmacokinetics were analysed in the interventional arm of the Italian population.

RESULTS

There were 162 blood samples from 32 infants (22 male and 10 female). The median (IQR) age was 12 (5.2-15.5) months, weight 9.9 (7.3-10.8) kg. Duration of anaesthesia ranged from 2-6 hours. None of the children were born premature (median postnatal age 39 weeks, IQR 38-40 weeks). A 3-compartment PK model that incorporated allometric scaling and a maturation function demonstrated plasma concentration observations from the current Italian arm of the TREX study were consistent with those predicted by a "universal" model using pooled data obtained from neonates to adults.

CONCLUSIONS

This current PK analysis from the Italian arm of the TREX study confirms that plasma concentration of dexmedetomidine is predictable using known covariates such as age and size. The initial target concentration (0.6 μg.L-1 ) used to sedate children cared for in the intensive care after cardiac surgery was inadequate for infants in the current TREX study. A target concentration 1 mcg.L-1 , corresponding to a loading dose of 1 mcg.kg-1 followed by an infusion of 1 mcg.kg-1 .hour-1 , provided adequate sedation.

Single bolus dexmedetomidine versus propofol for treatment of pediatric emergence delirium following general anesthesia

BACKGROUND

Pediatric emergence delirium is a psychomotor disorder occurring in the early postanesthetic stage. There is no clear consensus regarding its treatment; however, dexmedetomidine and propofol have both been shown to be effective.

AIM

In this single-center, randomized, double-blind prospective study, we compared the efficacy of dexmedetomidine against that of propofol in the treatment of established emergence delirium in pediatric patients undergoing general anesthesia.

METHODS

Patients aged 1-14 years, with ASA I or II and severe emergence delirium (Pediatric Anesthesia Emergence Delirium score of ≥15) during the postoperative period following general anesthesia, were randomized to receive intravenous bolus injection of 0.5 μg.kg^-1 dexmedetomidine or 1 mg.kg^-1 propofol. The primary outcome was the pediatric anesthesia emergence delirium (PAED) score after treatment, and the secondary outcome was the recovery time in the postanesthetic care unit.

RESULTS

Of the 53 patients who participated in the study, 26 (49%) were treated with dexmedetomidine and 27 (51%) with propofol. In the dexmedetomidine group, a single-dose intervention was effective for all patients (100%); whereas in the propofol group, 19 patients (70.4%) had PAED score of <12 after the first dose (p = .004; relative risk [95% confidence interval] = 0.1422 [0.113-1.815]). No significant difference in recovery time (median [IQR (range)]) was observed between the dexmedetomidine (20[14-30(10-45)]) and propofol groups (25 [20-40 (10-50)]; p = .056; 95% confidence interval = 0.113-1.815).

CONCLUSIONS

A single bolus of 0.5 μg.kg^-1 of dexmedetomidine was more effective than a single bolus of 1 mg.kg^-1 of propofol in treating emergence delirium during the early postanesthetic stage.

Effects of opioid-reduced anesthesia during scoliosis surgery in children: a prospective observational study

Aims: Opioid-reduced anesthesia (ORA) was suggested to decrease morphine consumption after adolescent idiopathic scoliosis (AIS) surgery and incidence of chronic pain. Materials & methods: A prospective analysis using the ORA in AIS surgery was performed. Two cohorts were compared: a control group (opioid-based anesthesia) and the ORA group. The main outcome was morphine consumption at day 1. Results: 33 patients operated for AIS using ORA were compared with 36 with opioid-based anesthesia. Morphine consumption was decreased in the ORA group (1.1 mg.kg^-1 [0.2-2] vs 0.8 mg.kg^-1 [0.3-2]; p = 0.02) at day 1. Persistent neuropathic pain at 1 year was decreased in the ORA group (p = 0.02). Conclusion: The ORA protocol is efficient to reduce postoperative morphine consumption in AIS surgery and preventing neuropathic pain.

Combined effects of dexmedetomidine and vatinoxan infusions on minimum alveolar concentration and cardiopulmonary function in sevoflurane-anesthetized dogs

OBJECTIVE

To evaluate the effects of combined infusions of vatinoxan and dexmedetomidine on inhalant anesthetic requirement and cardiopulmonary function in dogs.

STUDY DESIGN

Prospective experimental study.

METHODS

A total of six Beagle dogs were anesthetized to determine sevoflurane minimum alveolar concentration (MAC) prior to and after an intravenous (IV) dose (loading, then continuous infusion) of dexmedetomidine (4.5 μg kg^-1 hour^-1) and after two IV doses of vatinoxan in sequence (90 and 180 μg kg^-1 hour^-1). Blood was collected for plasma dexmedetomidine and vatinoxan concentrations. During a separate anesthesia, cardiac output (CO) was measured under equivalent MAC conditions of sevoflurane and dexmedetomidine, and then with each added dose of vatinoxan. For each treatment, cardiovascular variables were measured with spontaneous and controlled ventilation. Repeated measures analyses were performed for each response variable; for all analyses, p < 0.05 was considered significant.

RESULTS

Dexmedetomidine reduced sevoflurane MAC by 67% (0.64 ± 0.1%), mean ± standard deviation in dogs. The addition of vatinoxan attenuated this to 57% (0.81 ± 0.1%) and 43% (1.1 ± 0.1%) with low and high doses, respectively, and caused a reduction in plasma dexmedetomidine concentrations. Heart rate and CO decreased while systemic vascular resistance increased with dexmedetomidine regardless of ventilation mode. The co-administration of vatinoxan dose-dependently modified these effects such that cardiovascular variables approached baseline.

CONCLUSIONS AND CLINICAL RELEVANCE

IV infusions of 90 and 180 μg kg^-1 hour^-1 of vatinoxan combined with 4.5 μg kg^-1 hour^-1 dexmedetomidine provide a meaningful reduction in sevoflurane requirement in dogs. Although sevoflurane MAC-sparing properties of dexmedetomidine in dogs are attenuated by vatinoxan, the cardiovascular function is improved. Doses of vatinoxan >180 μg kg^-1 hour^-1 might improve cardiovascular function further in combination with this dose of dexmedetomidine, but beneficial effects on anesthesia plane and recovery quality may be lost.

Fifty Percent Effective Dose of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography in Children With Cyanotic and Acyanotic Congenital Heart Disease

OBJECTIVES

To determine the 50% and 95% effective dose of intranasal dexmedetomidine sedation for transthoracic echocardiography in children with cyanotic and acyanotic congenital heart disease.

DESIGN

A prospective, nonrandomized study.

SETTING

A tertiary care teaching hospital.

PARTICIPANTS

Patients younger than 18 months with known or suspected congenital heart disease scheduled for transthoracic echocardiography with sedation.

INTERVENTIONS

Patients were divided into a cyanotic group (blood oxygen saturation <85%) or an acyanotic group (blood oxygen saturation ≥85%). This study used Dixon's up-and-down method sequential allocation design. In both groups, the initial dose of intranasal dexmedetomidine was 2 μg/kg and the gradient of increase or decrease was 0.25 μg/kg.

MEASUREMENTS AND MAIN RESULTS

The 50% effective dose (95% confidence interval) of intranasal dexmedetomidine sedation for transthoracic echocardiography was 3.2 (2.78-3.55) μg/kg and 1.9 (1.69-2.06) μg/kg in the cyanotic and acyanotic groups, respectively. None of the patients experienced significant adverse events.

CONCLUSION

The 50% (95% confidence intervals) effective doses of intranasal dexmedetomidine sedation for transthoracic echocardiography were 3.2 (2.78-3.55) μg/kg and 1.9 (1.69-2.06) μg/kg in children with cyanotic and acyanotic congenital heart disease, respectively.

Results of a phase 1 multicentre investigation of dexmedetomidine bolus and infusion in corrective infant cardiac surgery

BACKGROUND

Dexmedetomidine (DEX) is increasingly used intraoperatively in infants undergoing cardiac surgery. This phase 1 multicentre study sought to: (i) determine the safety of DEX for cardiac surgery with cardiopulmonary bypass; (ii) determine the pharmacokinetics (PK) of DEX; (iii) create a PK model and dosing for steady-state DEX plasma levels; and (iv) validate the PK model and dosing.

METHODS

We included 122 neonates and infants (0-180 days) with D-transposition of the great arteries, ventricular septal defect, or tetralogy of Fallot. Dose escalation was used to generate NONMEM® PK modelling, and then validation was performed to achieve low (200-300 pg ml-1), medium (400-500 pg ml-1), and high (600-700 pg ml-1) DEX plasma concentrations.

RESULTS

Five of 122 subjects had adverse safety outcomes (4.1%; 95% confidence interval [CI], 1.8-9.2%). Two had junctional rhythm, two had second-/third-degree atrioventricular block, and one had hypotension. Clearance (CL) immediately postoperative and CL on CPB were reduced by approximately 50% and 95%, respectively, compared with pre-CPB CL. DEX clearance after CPB was 1240 ml min-1 70 kg-1. Age at 50% maximum clearance was approximately 2 days, and that at 90% maximum clearance was 18 days. Overall, 96.1% of measured DEX concentrations fell within the 5th-95th percentile prediction intervals in the PK model validation. Dosing strategies are recommended for steady-state DEX plasma levels ranging from 200 to 1000 pg ml-1.

CONCLUSIONS

When used with a careful dosing strategy, DEX results in low incidence and severity of adverse safety events in infants undergoing cardiac surgery with cardiopulmonary bypass. This validated PK model should assist clinicians in selecting appropriate dosing. The results of this phase 1 trial provide preliminary data for a phase 3 trial of DEX neuroprotection.

CLINICAL TRIALS REGISTRATION

NCT01915277.

Population Pharmacokinetics and Pharmacodynamics of Dexmedetomidine in Children Undergoing Ambulatory Surgery

BACKGROUND

Dexmedetomidine (DEX) is an α-2 adrenergic agonist with sedative and analgesic properties. Although not approved for pediatric use by the Food and Drug Administration, DEX is increasingly used in pediatric anesthesia and critical care. However, very limited information is available regarding the pharmacokinetics of DEX in children. The aim of this study was to investigate DEX pharmacokinetics and pharmacodynamics (PK-PD) in Mexican children 2-18 years of age who were undergoing outpatient surgical procedures.

METHODS

Thirty children 2-18 years of age with American Society of Anesthesiologists physical status score of I/II were enrolled in this study. DEX (0.7 μg/kg) was administered as a single-dose intravenous infusion. Venous blood samples were collected, and plasma DEX concentrations were analyzed with a combination of high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry. Population PK-PD models were constructed using the Monolix program.

RESULTS

A 2-compartment model adequately described the concentration-time relationship. The parameters were standardized for a body weight of 70 kg by using an allometric model. Population parameters estimates were as follows: mean (between-subject variability): clearance (Cl) (L/h × 70 kg) = 20.8 (27%); central volume of distribution (V1) (L × 70 kg) = 21.9 (20%); peripheral volume of distribution (V2) (L × 70 kg) = 81.2 (21%); and intercompartmental clearance (Q) (L/h × 70 kg) = 75.8 (25%). The PK-PD model predicted a maximum mean arterial blood pressure reduction of 45% with an IC50 of 0.501 ng/ml, and a maximum heart rate reduction of 28.9% with an IC50 of 0.552 ng/ml.

CONCLUSIONS

Our results suggest that in Mexican children 2-18 years of age with American Society of Anesthesiologists score of I/II, the DEX dose should be adjusted in accordance with lower DEX clearance.

The pearls of pediatric sedation: polish the old and embrace the new

Over the past decade, as the complexity and breadth of pediatric procedures increases, the actual choices of approved sedatives have remained relatively stagnant. Since the introduction of midazolam, there has not been a sedative approved for pediatric labelling until December 2018. This December, the European approval of ADV6209 (Ozalin) for pediatric usage marked the newest addition to the pediatric sedative armamentarium in over a decade. This review is timely and significant because it will provide a balanced evaluation of the most common sedatives in use today, the most recent sedative to be approved and, most importantly, a critical look at the literature supporting the latest approaches to the most commonly performed procedures.

Propofol Versus Dexmedetomidine for Procedural Sedation in a Pediatric Population

OBJECTIVES

Frequently, infants and children require sedation to facilitate noninvasive procedures and imaging studies. Propofol and dexmedetomidine are used to achieve deep procedural sedation in children. The objective of this study was to compare the clinical safety and efficacy of propofol versus dexmedetomidine in pediatric patients undergoing sedation in a pediatric sedation unit.

METHODS

A retrospective analysis of patients sedated with either propofol or dexmedetomidine in a pediatric sedation unit by pediatric emergency physicians was performed. Both medications were dosed per protocol with propofol 2 mg/kg induction and 150 μg · kg^-1 · min^-1 maintenance and dexmedetomidine 3 μg/kg induction for 10 minutes and 2 μg · kg^-1 · h^-1maintenance. The variables collected included drug dose, sedation time (time that the drug was given to the completion of the procedure), recovery time (end of the study to the return to the presedation sedation score for 15 minutes), need for dose rate changes, airway management, and adverse events.

RESULTS

A total of 2432 children were included- 1503 who received propofol and 929 who received dexmedetomidine. Propofol and dexmedetomidine resulted in successful completion of the study in 98.8% and 99.7%, respectively (P = 0.02). The mean recovery time for propofol was 34.3 minutes, compared with 65.6 minutes for dexmedetomidine (P < 0.001). The need for unexpected airway management was 9.7% for propofol and 2.2% for dexmedetomidine (P < 0.001). Adverse events occurred in 8.6% and 6% of patients in the propofol and dexmedetomidine groups, respectively (P = 0.02).

CONCLUSIONS

Propofol use led to significantly shorter recovery times, with an increased need for airway management, but rates of bag-mask ventilation (2.3%), airway obstruction (1.1%), and desaturation (1.6%) were low. No patients required intubation. Propofol is a reasonable alternative to dexmedetomidine, with a clinically acceptable safety profile.

Non-invasive measurement of cardiac output in children with repaired coarctation of the aorta using electrical cardiometry compared to transthoracic Doppler echocardiography

OBJECTIVE

To evaluate the equivalence of the ICON^® electrical cardiometry (EC) haemodynamic monitor to measure cardiac output (CO) relative to transthoracic Doppler echocardiography (TTE) in paediatric patients with repaired coarctation of the aorta (CoA).

APPROACH

A group of n  =  28 CoA patients and n  =  27 matched controls were enrolled. EC and TTE were performed synchronously on each participant and CO measurements compared using linear regression and Bland-Altman analysis. The CoA group was further subdivided into two groups, with n  =  10 and without n  =  18 increased left ventricular outflow tract velocity (iLVOTv) for comparison.

MAIN RESULTS

CO measurements from EC and TTE in controls showed a strong correlation (R  =  0.80, p  <  0.001) and an acceptable percentage error (PE) of 28.1%. However, combining CoA and control groups revealed a moderate correlation (R  =  0.57, p  <  0.001) and a poor PE (44.2%). We suspected that the CO in a subset of CoA participants with iLVOTv was overestimated by TTE. Excluding the iLVOTv CoA participants improved the correlation (R  =  0.77, p  <  0.001) and resulted in an acceptable PE of 31.2%.

SIGNIFICANCE

CO measurements in paediatric CoA patients in the absence of iLVOTv are clinically equivalent between EC and TTE. The presence of iLVOTv may impact the accuracy of CO measurement by TTE, but not EC.

Supraventricular tachycardia after withdrawal of prolonged dexmedetomidine infusion in a paediatric patient without heart disease

WHAT IS KNOWN AND OBJECTIVE

Dexmedetomidine (DEX) has been reported to be safe in paediatric patients.

CASE DESCRIPTION

We present the case of a girl without heart disease admitted at our PICU due to an influenza A acute respiratory distress syndrome, who suffered a paroxysmal supraventricular tachycardia (PSVT) twelve hours after DEX progressive withdrawal was completed.

WHAT IS NEW AND CONCLUSION

This is the first report of PSVT as an adverse reaction to DEX in a paediatric patient without heart disease.

Intranasal Dexmedetomidine as a Sedative for Pediatric Procedural Sedation

OBJECTIVE

This study seeks to evaluate the efficacy and safety of intranasal (IN) dexmedetomidine as a sedative medication for non-invasive procedural sedation.

METHODS

Subjects 6 months to 18 years of age undergoing non-invasive elective procedures were included. Dexmedetomidine (3 mcg/kg) was administered IN 40 minutes before the scheduled procedure time. The IN dexmedetomidine cohort was matched and compared to a cohort of 690 subjects who underwent sedation for similar procedures without the use of dexmedetomidine to evaluate for observed events/interventions and procedural times.

RESULTS

One hundred (92%) of the 109 included subjects were successfully sedated with IN dexmedetomidine. There were no significant differences in the rate of observed events/interventions in comparison to the non-dexmedetomidine cohort. However, the IN dexmedetomidine group had a longer postprocedure sleep time when compared to the non-dexmedetomidine cohort (p < 0.001), which had a significant effect on recovery time (p = 0.024). Also, the dexmedetomidine cohort had longer procedure time and total admit time (p < 0.001 and p = 0.037, respectively).

CONCLUSIONS

IN dexmedetomidine may be used for non-invasive pediatric procedural sedation. Subjects receiving IN dexmedetomidine had a similar rate of observed events/interventions as the subjects receiving non-dexmedetomidine sedation, with the exception of sleeping time. Also, patients sedated with IN dexmedetomidine had longer time to discharge, procedure time, and total admit time in comparison to other forms of sedation.

Pediatric Procedural Sedation Using Dexmedetomidine: A Report From the Pediatric Sedation Research Consortium

OBJECTIVES

Dexmedetomidine (DEX) is widely used in pediatric procedural sedation (PPS) by a variety of pediatric subspecialists. The objective of our study was to describe the overall rates of adverse events and serious adverse events (SAEs) when DEX is used by various pediatric subspecialists.

METHODS

Patients from the Pediatric Sedation Research Consortium (PSRC) database were retrospectively reviewed and children that received DEX as their primary sedation agent for elective PPS were identified. Demographic and clinical data, provider subspecialty, and sedation-related complications were abstracted. SAEs were defined as death, cardiac arrest, upper airway obstruction, laryngospasm, emergent airway intervention, unplanned hospital admission/increased level of care, aspiration, or emergency anesthesia consult. Event rates and 95% confidence intervals (CIs) were calculated.

RESULTS

During the study period, 13 072 children were sedated using DEX, accounting for 5.3% of all sedation cases entered into the PSRC. Of the sedated patients, 73% were American Society of Anesthesiologists Physical Status class 1 or 2. The pediatric providers responsible for patients sedated with DEX were anesthesiologists (35%), intensivists (34%), emergency medicine physicians (12.7%), hospitalists (1.1%), and others (17%). The overall AE rate was 466/13 072 (3.6%, 95% CI 3.3% to 3.9%). The overall SAE rate was 45/13 072 (0.34%, 95% CI 0.19% to 0.037%). Airway obstruction was the most common SAE: 35/13 072 (0.27%, 95% CI 0.19% to 0.37%). Sedations were successful in 99.7% of cases.

CONCLUSIONS

We report the largest series of PPS using DEX outside the operating room. Within the PSRC, PPS performed using DEX has a very high success rate and is unlikely to yield a high rate of SAEs.

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.

Dexmedetomidine-ketamine combination and caudal block for superficial lower abdominal and genital surgery in children

BACKGROUND

The use of dexmedetomidine-ketamine combination to perform different diagnostic and surgical pediatric procedures has increased. The optimal ketamine dose to combine with dexmedetomidine has not been determined. The goal of this study was to determine the ED50 and ED95 of ketamine, which in combination with, dexmedetomidine (1 μg · kg(-1)) provides an adequate anesthetic effect to perform a caudal block and then the ensuing superficial lower abdominal or genital surgery.

MATERIAL AND METHODS

Twenty-five patients, aged 1-8 years, scheduled for superficial lower abdominal or genital surgery, were studied. All patients received an intravenous dose of dexmedetomidine 1 μg · kg(-1) and a random dose of ketamine from 1 mg · kg(-1) to 2 mg · kg(-1). After ketamine administration, a caudal block was performed and then surgery was initiated. Hemodynamics, respiratory variables, sedation level, and postoperative complications were recorded. The ED50 and ED95 of ketamine were calculated using logistic regression analysis.

RESULTS

The ED50 and ED95 of ketamine to perform a caudal block were 1.53 (1.29-1.76) mg · kg(-1) and 2.25 (1.63-2.88) mg · kg(-1), respectively. The ED50 and ED95 of ketamine to perform a caudal block and to complete the entire procedure were 1.76 (1.57-1.95) mg · kg(-1), and 2.21 (1.77-2.64) mg · kg(-1), respectively. Three patients presented mild, self-limited, intraoperative bradycardia.

CONCLUSIONS

These results suggest that adding ketamine 2 mg · kg(-1) to dexmedetomidine 1 μg · kg(-1) should produce an effective anesthetic level to perform a caudal block and the ensuing superficial lower abdominal or genital surgery in children.

Intranasal dexmedetomidine for sedation for pediatric computed tomography imaging

This prospective observational pilot study evaluated the aerosolized intranasal route for dexmedetomidine as a safe, effective, and efficient option for infant and pediatric sedation for computed tomography imaging. The mean time to sedation was 13.4 minutes, with excellent image quality, no failed sedations, or significant adverse events.

TRIAL REGISTRATION

Registered with ClinicalTrials.gov: NCT01900405.

Anesthesia and the pediatric cardiac catheterization suite: a review

Advances in technology over the last couple of decades have caused a shift in pediatric cardiac catheterization from a primary focus on diagnostics to innovative therapeutic interventions. These improvements allow patients a wider range of nonsurgical options for treatment of congenital heart disease. However, these therapeutic modalities can entail higher risk in an already complex patient population, compounded by the added challenges inherent to the environment of the cardiac catheterization suite. Anesthesiologists caring for children with congenital heart disease must understand not only the pathophysiology of the disease but also the effects the anesthetics and interventions have on the patient in order to provide a safe perioperative course. It is the aim of this article to review the latest catheterization modalities offered to patients with congenital heart disease, describe the unique challenges presented in the cardiac catheterization suite, list the most common complications encountered during catheterization and finally, to review the literature regarding different anesthetic drugs used in the catheterization lab.

Bradycardia in perspective-not all reductions in heart rate need immediate intervention

According to Wikipedia, the word 'bradycardia' stems from the Greek βραδύς, bradys, 'slow', and καρδία, kardia, 'heart'. Thus, the meaning of bradycardia is slow heart rate but not necessarily too slow heart rate. If looking at top endurance athletes they may have a resting heart rate in the very low thirties without needing emergent intervention with anticholinergics, isoprenaline, epinephrine, chest compressions or the insertion of an emergency pacemaker (Figure 1). In fact, they withstand these episodes without incident, accommodating with a compensatory increase in stroke volume to preserve and maintain cardiac output. With this in mind, it is difficult for the authors to fully understand and agree with the general sentiment amongst many pediatric anesthesiologists that all isolated bradycardia portends impending doom and must be immediately treated with resuscitative measures.

Low-dose intramuscular dexmedetomidine as premedication: a randomized controlled trial

BACKGROUND

Dexmedetomidine-induced bradycardia or hypotension has recently attracted considerable attention because of potentially grave consequences, including sinus arrest and refractory cardiogenic shock. A route other than intravenous injection or a low dose may help minimize cardiovascular risks associated with dexmedetomidine. However, few studies have addressed the clinical effects of low-dose intramuscular dexmedetomidine as premedication.

MATERIAL AND METHODS

Forty American Society of Anesthesiologists physical status I adult patients undergoing suspension laryngoscopic surgery were randomized to receive intramuscular dexmedetomidine (1 µg·kg-1) or midazolam (0.02 mg·kg-1) 30 minutes prior to anaesthesia induction. The sedative, hemodynamic, and adjuvant anaesthetic effects of both premedications were assessed.

RESULTS

The levels of sedation (Observer's Assessment of Alertness/Sedation scales) and anxiety (visual analog score) at pre-induction, and the times to eye-opening and extubation, were not different between the groups. The heart rate response following tracheal intubation and extubation, and mean arterial pressure responses after extubation, were attenuated in the dexmedetomidine group compared to the midazolam group. No bradycardia or hypotension was noted in any patients. Propofol target concentrations at intubation and at start and completion of surgery were decreased in the dexmedetomidine group, whereas no difference in respective remifentanil levels was detected.

CONCLUSIONS

This study provides further evidence that dexmedetomidine premedication in low dose (1 μg·kg-1) by intramuscular route can induce preoperative sedation and adjuvant anaesthetic effects without clinically significant bradycardia or hypotension.

Pharmacokinetics of dexmedetomidine combined with therapeutic hypothermia in a piglet asphyxia model

Background

The highly selective α₂-adrenoreceptor agonist, dexmedetomidine, exerts neuroprotective, analgesic, anti-inflammatory and sympatholytic properties that may be beneficial for perinatal asphyxia. The optimal safe dose for pre-clinical newborn neuroprotection studies is unknown.

Methods

Following cerebral hypoxia-ischaemia, dexmedetomidine was administered to nine newborn piglets in a de-escalation dose study in combination with hypothermia (whole body cooling to 33.5°C). Dexmedetomidine was administered with a loading dose of 1 μg/kg and maintenance infusion at doses from 10 to 0.6 μg/kg/h. One additional piglet was not subjected to hypoxia-ischaemia. Blood for pharmacokinetic analysis was sampled pre-insult and frequently post-insult. A one-compartment linear disposition model was used to fit data. Population parameter estimates were obtained using non-linear mixed effects modelling.

Results

All dexmedetomidine infusion regimens led to plasma concentrations above those associated with sedation in neonates and children (0.4–0.8 μg/l). Seven out of the nine piglets with hypoxia-ischaemia experienced periods of bradycardia, hypotension, hypertension and cardiac arrest; all haemodynamic adverse events occurred in piglets with plasma concentrations greater than 1 μg/l. Dexmedetomidine clearance was 0.126 l/kg/h [coefficient of variation (CV) 46.6.%] and volume of distribution was 3.37 l/kg (CV 191%). Dexmedetomidine clearance was reduced by 32.7% at a temperature of 33.5°C. Dexmedetomidine clearance was reduced by 55.8% following hypoxia-ischaemia.

Conclusions

Dexmedetomidine clearance was reduced almost tenfold compared with adult values in the newborn piglet following hypoxic-ischaemic brain injury and subsequent therapeutic hypothermia. Reduced clearance was related to cumulative effects of both hypothermia and exposure to hypoxia. High plasma levels of dexmedetomidine were associated with major cardiovascular complications.

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.

Dexmedetomidine versus midazolam for sedation in upper gastrointestinal endoscopy

OBJECTIVES

To investigate the efficacy and safety of sedation with dexmedetomidine in upper gastrointestinal endoscopy.

METHODS

Patients with ASA physical status I-II undergoing elective upper gastrointestinal endoscopy were randomly allocated to receive dexmedetomidine or midazolam for conscious sedation. Continuous peripheral oxygen saturation (SpO2), heart rate, mean arterial pressure (MAP), Ramsay Sedation Scale (RSS) and numeric rating scale pain scores were recorded before, during and after the procedure. Patients completed a post-procedure satisfaction questionnaire.

RESULTS

Patients in the midazolam group (n = 30) experienced a significant decrease in MAP during sedation compared with pre-sedation values. Patients in the dexmedetomidine group (n = 30) had significantly higher SpO2 and RSS scores during sedation than those in the midazolam group. Overall satisfaction was higher in the dexmedetomidine group than the midazolam group. There were no clinically significant complications in either group.

CONCLUSION

Dexmedetomidine has a good safety profile and is an effective sedative for use in upper gastrointestinal endoscopy.

Hemodynamic responses to dexmedetomidine in critically injured intubated pediatric burned patients: a preliminary study

Because of ineffectiveness and tolerance to benzodiazepines and opioids developing with time, drugs acting via other receptor systems (eg, α-2 agonists) have been advocated in burn patients to improve sedation and analgesia. This study in severely burned pediatric subjects examined the hemodynamic consequences of dexmedetomidine (Dex) administration. Eight intubated patients with ≥20 to 79% TBSA burns were studied between 7 and 35 days after injury. After baseline measurements of mean arterial blood pressure and heart rhythm were taken, each patient received a 1.0 µg/kg bolus of Dex followed by an ascending dose infusion protocol (0.7-2.5 µg/kg/hr), with each dose administered for 15 minutes. There was significant hypotension (27±7.5%, average drop in mean arterial pressure [MAP] ± SD), and a decrease in heart rate (HR; 19% ± 7, average drop in HR ± SD). The average HR decreased from 146 beats per minute to 120. No bradycardia (HR < 60) or heart blocks were observed. In three patients, the MAP decreased to <50mm Hg with the bolus dose of Dex. Of the remaining five patients, three patients completed the study receiving the highest infusion dose of Dex (2.5 µg/kg/hr), whereas in 2 patients the infusion part of the study was begun, but the study was stopped due to persistent hypotension (MAP < 50mm Hg). These observations indicate that a bolus dose of Dex (1.0 µg/kg for 10 minutes) and high infusion rates may require fluid resuscitation or vasopressor support to maintain normotension in critically injured pediatric burn patients.

The hemodynamic response to dexmedetomidine loading dose in children with and without pulmonary hypertension

BACKGROUND

Dexmedetomidine, an α-2 receptor agonist, is widely used in children with cardiac disease. Significant hemodynamic responses, including systemic and pulmonary vasoconstriction, have been reported after dexmedetomidine administration. Our primary goal of this prospective, observational study was to quantify the effects of dexmedetomidine initial loading doses on mean pulmonary artery pressure (PAP) in children with and without pulmonary hypertension.

METHODS

Subjects were children undergoing cardiac catheterization for either routine surveillance after cardiac transplantation (n = 21) or pulmonary hypertension studies (n = 21). After anesthetic induction with sevoflurane and tracheal intubation, sevoflurane was discontinued and anesthesia was maintained with midazolam 0.1 mg/kg i.v. (or 0.5 mg/kg orally preoperatively) and remifentanil i.v. infusion 0.5 to 0.8 μg/kg/min. Ventilation was mechanically controlled to maintain PCO2 35 to 40 mm Hg. When end-tidal sevoflurane was 0% and fraction of inspired oxygen (FIO2) was 0.21, baseline heart rate, mean arterial blood pressure, PAP, right atrial pressure, pulmonary artery occlusion pressure, right ventricular end-diastolic pressure, cardiac output, and arterial blood gases were measured, and indexed systemic vascular resistance, indexed pulmonary vascular resistance, and cardiac index were calculated. Each subject then received a 10-minute infusion of dexmedetomidine of 1 μg/kg, 0.75 μg/kg, or 0.5 μg/kg. Measurements and calculations were repeated at the conclusion of the infusion.

RESULTS

Most hemodynamic responses were similar in children with and without pulmonary hypertension. Heart rate decreased significantly, and mean arterial blood pressure and indexed systemic vascular resistance increased significantly. Cardiac index did not change. A small, statistically significant increase in PAP was observed in transplant patients but not in subjects with pulmonary hypertension. Changes in indexed pulmonary vascular resistance were not significant.

CONCLUSION

Dexmedetomidine initial loading doses were associated with significant systemic vasoconstriction and hypertension, but a similar response was not observed in the pulmonary vasculature, even in children with pulmonary hypertension. Dexmedetomidine does not appear to be contraindicated in children with pulmonary hypertension.

Cardiac output assessed by non-invasive monitoring is associated with ECG changes in children with critical asthma

The primary aim of this study was to determine changes in CI and SI, if any, in children hospitalized with status asthmatics during the course of treatment as measured by non-invasive EC monitoring. The secondary aim was to determine if there is an association between Abnormal CI (defined as <5 or >95 % tile adjusted for age) and Abnormal ECG (defined as ST waves changes) Non-invasive cardiac output (CO) recordings were obtained daily from admission (Initial) to discharge (Final). Changes in CI and SI measurements were compared using paired t tests or 1-way ANOVA. The association between Abnormal CI on Initial CO recording and Abnormal ECG was analyzed by Fischer's exact test. Data are presented as mean ± SEM with mean differences reported with 95 % confidence interval; p < 0.05 was considered significant. Thirty-five children with critical asthma were analyzed. CI decreased from 6.2 ± 0.2 to 4.5 ± 0.1 [-1.6 (-0.04 to -0.37)] L/min/m(2) during hospitalization. There was no change in SI. There was a significant association between Abnormal Initial CI and Abnormal ECG (p = 0.02). In 11 children requiring prolonged hospitalization CI significantly decreased from 7.2 ± 0.5 to 4.0 ± 0.2 [-3.2 (-4.0 to -2.3)] L/min/m(2) and SI decreased from 51.2 ± 3.8 to 40.3 ± 2.0 [-11.0 (-17.6 to -4.4)] ml/beat/m(2) There was a significant decrease in CI in all children treated for critical asthma. In children that required a prolonged course of treatment, there was also a significant decrease in SI. Abnormal CI at Initial CO recording was associated with ST waves changes on ECG during hospitalization. Future studies are required to determine whether non-invasive CO monitoring can predict which patients are at risk for developing abnormal ECG.

Dexmedetomidine for patients undergoing diagnostic cardiac procedures: a noninferiority study

When anesthetizing children with congenital heart disease for diagnostic cardiac catheterization, anesthesiologists and cardiologists seek to use anesthetic regimens that yield minimal hemodynamic changes and allow for spontaneous ventilations. Recently, dexmedetomidine has been used as an anesthesia adjunct because of its sedative and analgesic properties and minimal ventilatory depressive effects. We tested the hypothesis that the combination of sevoflurane and dexmedetomidine is non-inferior to sevoflurane alone as it refers to hemodynamic measurements during diagnostic cardiac catheterization in children with a transplanted heart, one ventricle (Fontan procedure), or normal cardiac physiology. Patients were anesthetized with inhalation of sevoflurane in nitrous oxide/oxygen and, after baseline hemodynamic measurements, successive boluses of dexmedetomidine followed by continuous infusion were administered. In this study, non-inferiority was shown when differences at steady-state (dexmedetomidine + sevoflurane) compared to baseline (sevoflurane alone) and its associated 95% confidence interval fell completely within the range of plus or minus 20%. Forty-one (26 normal physiology, 9 cardiac transplantation, and 6 Fontan) patients were enrolled. Non-inferiority of sevoflurane + dexmedetomidine compared with sevoflurane alone was shown for heart rate, but not for arterial blood pressure in patients with normal and cardiac transplant physiology. In patients with normal cardiac physiology, non-inferiority was demonstrated for bispectral index. Therefore, while the lack of depressive respiratory effects and non-inferiority for heart rate are desirable, the lack of non-inferiority of dexmedetomidine + sevoflurane combination for arterial blood pressure do not justify the routine use of this combination compared with sevoflurane alone for children with congenital heart disease undergoing cardiac catheterization.

Long QT syndrome unmasked by dexmedetomidine: a case report

Dexmedetomidine is a selective alpha-2 adrenergic agonist that is used frequently for short-term sedation in children. It has been noted to cause hypertension, hypotension, bradycardia, and sinus pauses; however, QTc prolongation has not been reported with dexmedetomidine administration. We describe a case of marked QT prolongation with use of dexmedetomidine in a pediatric critical care setting. Clinicians should be vigilant about potential QT prolongation in patients on dexmedetomidine, particularly in those receiving multiple other medications.

Cardiac parameters in children recovered from acute illness as measured by electrical cardiometry and comparisons to the literature

Electrical cardiometry (EC) is a non-invasive cardiac output method that can assess cardiac index (CI) and stroke index (SI) but there are no reference values for children per se. The primary aim of this study was to develop reference values for clinical application. The secondary aim was to compare the EC measurements to published values. We performed a prospective observational study in patients (<21 years of age) without structural heart disease who had recovered from an acute illness. EC recordings in children that had normal heart rate and mean arterial blood pressure at discharge were eligible for analysis. The relationship of CI or SI and age in children was performed by regression analysis. Similar analysis was performed comparing measurements by EC to cardiac parameters values compiled from reference sources to assess bias in EC. Eighty-three children (2 weeks-21 years of age) were studied. There was a significant curvilinear relationship between CI or SI and age by EC (F-test, p < 0.05). Regression curves of cardiac parameters reported in the literature using 6 Fick's method, thermodilution, echocardiography and cardiac MRI were the same or higher than (0-19.6 %) values obtained with EC, with higher values being statistically significant (p < 0.05 all). There is a curvilinear relationship of CI or SI and age by EC in normal children. Cardiac parameters reported in the literature using alternative methods are different from those obtained with EC but are within acceptable ranges, with EC biased to underestimate CI. Adjustment of target value is required for EC goal-directed therapies.

Anesthesia for children with mitochondrial disorders: a national survey and review

PURPOSE

Mitochondrial diseases are a heterogeneous group of disorders. Patients with such diseases often need general anesthesia for diagnostic procedures and surgery; guidelines are lacking for the anesthetic care of these patients.

METHODS

We conducted a survey to investigate the current practices of pediatric anesthesiologists in the US in order to determine and document current practice. The survey consisted of twenty questions, including two demographic questions. A link to the survey was sent via email to members of the Society for Pediatric Anesthesia (2440), and was available online for 14 weeks.

RESULTS

Only 503 completed the survey: a response rate of 20.61 %. Among the responders, 93.2 % had children with mitochondrial disorders among their patients, but only 11 % had institutional guidelines for such cases in place. Among the responders, 80.3 % used the standard nil per os (NPO) status guidelines, while the rest give intravenous dextrose solution once NPO was in effect. Only 18.3 % took precautions for malignant hyperthermia during treatment. The majority of the practitioners chose sevoflurane as the safest inhaled agent for induction and maintenance (89.7 and 78.5 %, respectively). Regional anesthesia was deemed safe by 97.3 % of the responders. Lactated Ringer's solution was considered safe for these children by 49 %; only 47.8 % used dextrose-containing fluids for fluid replacement. The blood glucose was monitored by 72.7 %, and the majority (85 %) of this monitoring was done in a postanesthesia care unit.

CONCLUSION

Although the response rate was low, the majority of the responders provide care to these children routinely, so it can be inferred that the results of this survey are the closest published results to the true trend.

In vitro clearance of dexmedetomidine in extracorporeal membrane oxygenation

Dexmedetomidine (DMET) is a useful agent for sedation, both alone and in combination with other agents, in critically ill patients, including those on extracorporeal membrane oxygenation (ECMO) therapy. The drug is a clonidine-like derivative with an 8-fold greater specificity for the alpha 2-receptor while maintaining respiratory and cardiovascular stability. An in vitro ECMO circuit was used to study the effects of both “new” and “old” membrane oxygenators on the clearance of dexmedetomidine over the course of 24 hours. Once primed, the circuit was dosed with 840 μg of dexmedetomidine for a final concentration of 0.9 μg/ml. Serial samples, both pre- and post-oxygenator, were taken at 5, 60, 360, and 1440 minutes. Concentrations of the drug were expressed as a percentage of the original concentration remaining at each time point, both for new and old circuits. The new circuits were run at a standard flow for 24 hours, after which time the circuit was considered old and re-dosed with dexmedetomidine and the trial repeated. Results show that dexmedetomidine losses occur early in the circuits and then continue to decline. Initial losses in the first hour were 11+-65% and 59-73% pre- and post-oxygenator in the new circuit and 36-50% and 42-72% in the old circuit. The clearance of the drug through the membrane oxygenator exhibits no statistical difference between pre and post or new and old circuits. Dexmedetomidine can be expected to exhibit concentration changes during ECMO therapy. This effect appears to be more related to adsorption to the polyvinyl chloride (PVC) tubing rather than the membrane oxygenator. Dosage adjustments during dexmedetomidine administration during ECMO therapy may be warranted in order to maintain adequate serum concentrations and, hence, the desired degree of sedation.*(Lack of equilibrium)

Changes in cardiac output and stroke volume as measured by non-invasive CO monitoring in infants with RSV bronchiolitis

OBJECTIVES

The primary aim of the study was to determine the changes, if any, in cardiac output (CO) and stroke volume (SV) in normal infants with RSV bronchiolitis. The secondary aim was to determine whether changes in CO (ΔCO) and SV (ΔSV) are associated with changes in respiratory rate (ΔRR).

METHODS

Non-invasive CO recordings were obtained within 24 h of admission and discharge. Changes in CO, SV, and HR measurements were compared using paired t-tests. The effect of fluid boluses during the first 24 h (<60 or ≥60 cc/kg) on CO was assessed by 2 way ANOVA with time and group as main effect. The relationship between ΔRR and ΔCO or ΔSV was assessed by linear regression. Data is presented as Mean ± SEM and mean differences with 95 % confidence interval (p < 0.05 considered significant).

RESULTS

15 infants with RSV bronchiolitis were studied. CO (1.31 ± 0.13 to 1.11 ± 0.11 l/min (0.21 [0.04-0.37]) and SV (9.42 ± 1.10 to 7.75 ± 0.83 ml/beat (1.67 [0.21-3.12]) decreased significantly while HR (142.1 ± 4.0 to 145.2 ± 3.1 beats/min 3.0 [-5.3 to 11.3]) was unchanged. SV (p = 0.02) and CO (p = 0.04) significantly decreased only in the 7 infants that received ≥60 cc/kg. ΔRR correlated significantly with ΔCO (r (2) = 0.28, p = 0.04); but not with ΔSV (r (2) = 0.20, p = 0.09).

CONCLUSIONS

∆CO was related to ΔSV and not Δ HR. The ∆CO and ΔSV were affected by fluid boluses. ΔRR correlated with ΔCO. Non-invasive CO monitoring can trend CO and SV in infants with bronchiolitis during hospitalization.