A Minimal Opioid Postoperative Management Protocol in Congenital Cardiac Surgery: Safe and Effective.

There is evidence that reducing opioid exposure in children undergoing cardiac surgery may enhance postoperative recovery. We aimed to describe a minimal opioid postoperative management protocol in children undergoing cardiac surgery and our early outcomes with this strategy. We reviewed the medical records of children (6 months-18 years) who underwent elective cardiac surgery through a median sternotomy with cardiopulmonary bypass at our institution between 2016 and 2018. All patients were managed postoperatively using a standardized protocol. 101 children (median age 5 years) were included and 85% were extubated in the operating room. Although most patients (96%) received opioids postoperatively, opioid requirements decreased steadily over time, with 88%, 58%, and 18% of children receiving opioids on postoperative day 1, 2, and 3, respectively; 41% received no opioids after postoperative day 1. The median cumulative opioid exposure was 0.25 morphine milligram equivalents per kg (interquartile range, 0.10-0.75). Greater than mild pain was rare (<10%) at each time point. The rates of operative mortality and major complication were 0% and 3%, respectively. The median postoperative length of stay was 3 days, and 13% required readmission within 30 days. Age, cardiopulmonary bypass time, and number of benzodiazepine doses were independently associated with cumulative opioid exposure. Any complication, chest tube time, and higher STAT Category were independently associated with prolonged postoperative length of stay. A minimal opioid postoperative management protocol can be safe and effective in children undergoing cardiac surgery. Future prospective studies are needed to determine optimal practice and patient selection.

Ultrasound diaphragmatic manual and semi-automated motion measurements: Application in simulated and in vivo data of critically ill subjects.

BACKGROUND AND OBJECTIVE: Ultrasound diaphragmatic muscle motion characteristics may provide useful information about normal or abnormal diaphragmatic function and indicate diaphragmatic weakness, or paralysis. In the present work we propose and evaluate an integrated semi-automated analysis system for the quantitative analysis of ultrasonic motion from ultrasound diaphragmatic videos. METHODS: The proposed system was evaluated in simulated videos and in 13 patients, four of whom patients were mechanically ventilated. The major steps of the methodology were as follows: video normalization, despeckle filtering, generation of an M-Mode image, snakes segmentation, and motion measurements. RESULTS: The following manual (-/) vs semi-automated (/-), (median±IQR) measurements, which are routinely carried out by the experts, for assessing the severity of the disease, were computed. For the simulated videos the diaphragmatic excursion was 1.80±0.00 cm / 1.76±0.03 cm. For all the real ultrasound videos investigated in this study the following measurements were computed: (i) diaphragmatic excursion: 0.84±0.15 cm / 0.83±0.14 cm, (ii) inspiration time (Tinsp): 0.71±0.18 sec / 0.70±0.15 sec, (iii) total breathing time for one cycle (Ttot): 1.71±0.37 sec / 1.67±0.37 sec, (iv) diaphragmatic curve slope: 1.29±0.36 cm/sec / 1.27±0.36 cm/sec, and (v) relaxation rate (RR): 0.82±0.17 cm/sec / 0.82±0.18 cm/sec. CONCLUSIONS: Manual and semi-automated measurements were very close with non-statistical significant differences and strong correlations between them. It is anticipated that the proposed system might be useful in the clinical practice in the assessment and follow up of patients with diaphragmatic weakness or paralysis and aid in the separation of normal and abnormal diaphragmatic motion. Further validation and additional experimentation in a larger sample of videos and different patient groups is required.

Surfactant Administration During Pediatric Cardiac Extracorporeal Membrane Oxygenation.

We investigated the safety and efficacy of surfactant during extracorporeal membrane oxygenation (ECMO) in children with cardiac disease. ECMO patients administered surfactant (surfactant group) were compared with patients who did not receive (control). Criteria to administer surfactant were based on a decreased lung compliance of <0.5 ml/kg/cm H2O. Efficacy was determined on pulmonary compliance change and the radiography-based respiratory distress severity (RDS) score. For the surfactant group, lung compliance measurements and RDS scores were obtained just before the first surfactant administration (T0), 24 hours after the last dose of surfactant (T1), and 24 hours after ECMO decannulation (T2). For the control group, measurements were obtained at baseline (T0), day of ECMO decannulation (T1), and 24 hours after ECMO decannulation (T2). Eighty were on ECMO, 29 in the surfactant, and 51 in the control group. Surfactant group was younger 20 (6-140) vs. 28 (8-928) days old (p = 0.03), had longer ECMO duration 110 (58-192) vs. 46 (29-84) hours (p = 0.001), and had longer mechanical ventilation 16 (11-26) vs. 7 (5-9) days (p = 0.003). The lung compliance and RDS scores in the surfactant group improved significantly between baseline and 24 hours after decannulation, 0.36 ± 0.13 vs. 0.5 ± 0.12 ml/kg/cm H2O (p = 0.002) and 13 ± 3 vs. 12 ± 2 (p = 0.04), respectively. None developed pneumothorax. Mild pulmonary hemorrhage occurred twice (one in each group). Hospital duration and survival were similar 36 (19-48) vs. 31 (18-48) days and 69% vs. 78% in surfactant and control groups, respectively. Although this is a relatively small study, surfactant appears to be safe in pediatric cardiac ECMO patients.

Array CGH as a first-tier test for neonates with congenital heart disease.

OBJECTIVE: Efficient diagnosis of an underlying genetic aetiology in a patient with congenital heart disease is essential to optimising clinical care. Copy number variants are one aetiology of congenital heart disease; the majority are identifiable by targeted fluorescence in situ hybridisation or array comparative genomic hybridisation, not by classical cytogenetic analysis. This study assessed the utility of array comparative genomic hybridisation as a first-tier diagnostic test for neonates with congenital heart disease. Study design A prospective chart review of neonates with congenital heart disease in the Cardiac Intensive Care Unit at Children's Hospital of Pittsburgh of UPMC was performed. Patients were tested by array comparative genomic hybridisation and classical cytogenetic analysis simultaneously. Data collected included all chromosome abnormalities detected, physical examination findings, and imaging results. McNemar's test was used to compare detection of array comparative genomic hybridisation and classical cytogenetic analysis. RESULTS: Of 45 patients, three (6.7%) had an abnormality detected by classical cytogenetic analysis and an additional 10 (22.2%) had a copy number variant detected by array comparative genomic hybridisation, highlighting an increased detection rate (p=0.008). Several of these copy number variants had unclear clinical significance, requiring additional investigation. The prevalence of dysmorphology and/or comorbidity in this population was 72%. Identification of dysmorphic features was greater when assessed by a geneticist than by providers of different subspecialties. CONCLUSIONS: Array comparative genomic hybridisation has significant clinical utility as a first-tier test in this population, but it carries the potential for incidental findings and results of uncertain clinical significance. Collaboration between cardiologists and medical geneticists is essential to providing optimal clinical care.

A phase II/III, multicenter, safety, efficacy, and pharmacokinetic study of dexmedetomidine in preterm and term neonates.

OBJECTIVE: To investigate the safety, efficacy, and pharmacokinetic profile of dexmedetomidine in preterm and full-term neonates ≥ 28 to ≤ 44 weeks gestational age. STUDY DESIGN: Forty-two intubated, mechanically ventilated patients (n = 42) were grouped by gestational age into group I (n = 18), ≥ 28 to <36 weeks, and group II (n = 24), ≥ 36 to ≤ 44 weeks. Within each age group, there were 3 escalating dose levels, including a loading dose (LD, µg/kg) followed by a maintenance dose (MD, µg · kg(-1) · h(-1)) for 6-24 hours: level 1, 0.05 LD/MD; level 2, 0.1 LD/MD; and level 3, 0.2 LD/MD. The primary endpoint was the number of patients requiring sedation as determined by the Neonatal Pain, Agitation, Sedation Scale. RESULTS: During dexmedetomidine infusion, 5% of Neonatal Pain, Agitation, Sedation Scale scores were >3, indicating agitation/pain, with 4 patients (10%) requiring more sedation and 17 (40%) requiring more analgesia. Though there was significant variability in pharmacokinetic variables, group I appeared to have lower weight-adjusted plasma clearance (0.3 vs 0.9 L · h(-1) · kg(-1)) and increased elimination half-life (7.6 vs 3.2 hours) compared with group II. Fifty-six adverse events (AEs) were reported in 26 patients (62%); only 3 AEs (5%) were related to dexmedetomidine. There were no serious AEs and no AEs or hemodynamic changes requiring dexmedetomidine discontinuation. CONCLUSION: Dexmedetomidine is effective for sedating preterm and full-term neonates and is well-tolerated without significant AEs. Preterm neonates had decreased plasma clearance and longer elimination half-life.

Cerebral regional oxygen saturation and serum neuromarkers for the prediction of adverse neurologic outcome in pediatric cardiac surgery.

BACKGROUND: The aim of this study is to determine the utility of non-invasive bedside neuromonitoring, including cerebral regional oxygen saturation (rSO2) measured by near-infrared spectroscopy and serum biomarkers, in identifying children at risk from adverse neurological outcome after heart surgery. METHODS: Prospective observational study including 39 consecutive children undergoing heart surgery with cardiopulmonary bypass (CPB) and normal neurologic exam prior to surgery. Cerebral rSO2 was measured at baseline (prior to surgery) and then continuously during surgery and for the first 16 h post-operatively. Neuromarkers [neuron-specific enolase (NSE), S100ß, glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF)] were measured in serum at baseline, immediately after CPB and at 16 h post-operatively. Adverse neurological outcome was defined as an abnormal pediatric cerebral performance category (PCPC) scale score at 12 months after surgery. RESULTS: Sixteen children (41 %) had an abnormal PCPC scale score at the 12-month evaluation after surgery. In children with unfavorable neurological outcomes, mean cerebral rSO2 values were lower and the area-under-the-curve below a threshold of 40 and 20% below baseline were also increased. No significant differences were found in serum neuromarkers between groups at the time points that were assessed. CONCLUSIONS: Bedside determination of cerebral rSO2 may have some utility in identifying children at risk for adverse neurological outcome after heart surgery in children. Additional studies that are sufficiently powered to control for the many covariates in this patient population will be required to fully interrogate this important question. The role of serum neuromarkers in the immediate post-operative period do not appear to be helpful in this question, though more thorough interrogation of delayed periods may ultimately demonstrate some utility in answering this question.

Total cavopulmonary connection in patients with apicocaval juxtaposition: optimal conduit route using preoperative angiogram and flow simulation.

OBJECTIVES: Single ventricle with apicocaval juxtaposition (ACJ) is a rare, complex anomaly, in which the optimal position of the conduit for completion of total cavopulmonary connection (TCPC) is still controversial. The purpose of this study was to identify a preoperative method for optimal conduit position using the IVC anatomy and computational fluid dynamics (CFD). METHODS: Twenty-four patients with ACJ (5.3 ± 5.7 years) who underwent TCPC were enrolled. A conduit was placed ipsilateral to the cardiac apex in each of 11 patients, of which 9 were intra-atrial and 2 extracardiac (group A) and, in a further 13 patients, extracardiac on the contralateral side (group B). As control, 10 patients with tricuspid atresia were also enrolled (group C). The location of the IVC in relation to the spine was evaluated from the frontal view of preoperative angiogram, using the following index: IVC-index = IVC width overlapping the vertebra/width of the vertebra × 100%. Energy loss was calculated by CFD simulation. RESULTS: IVC-index of group B was larger than groups A and C (45 ± 26 vs. 20 ± 21 and 28 ± 19%, P = 0.03). Postoperative catheterizations showed that, due to its curvature, conduit length in group B was significantly longer than the others (65 ± 12 vs. 36 ± 14 and 44 ± 10 mm, P < 0.001), although there was no statistical difference in central venous pressure or cardiac output. CFD studies revealed less energy loss in group A conduits compared with group B (1.6 ± 0.3 vs. 3.6 ± 0.6 mW, P = 0.05), although this did not appear to be clinically significant. Moreover, CFD simulation showed significant energy loss within the Fontan circulation when the conduit was either compressed or kinked: 4.9 and 18.2 mW respectively. CONCLUSIONS: In patients with ACJ, placement of a straighter and shorter conduit on the ventricular apical side provides better laminar blood flow with less energy loss. However, conduit compression and kinking are far more detrimental to the Fontan circulation. A preoperative IVC-index is pivotal for avoiding these factors and deciding the optimal conduit route.

Dexmedetomidine: antiarrhythmic effects in the pediatric cardiac patient.

This report aims to provide a general description of the cardiovascular effects of dexmedetomidine, emphasizing its effects on conduction, and to give an evidence-based review of the literature regarding the use of dexmedetomidine to treat and prevent tachyarrhythmias in infants and children. A computerized bibliographic search of the literature on the use of dexmedetomidine to treat and prevent arrhythmias in infants and children was conducted. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Growing experience, mostly in the pediatric population, has demonstrated the potential therapeutic applications of dexmedetomidine in the acute treatment of arrhythmias. Additionally, its use during cardiac surgery has been associated with a decreased incidence of postoperative ventricular and supraventricular tachyarrhythmias. Although dexmedetomidine is not currently approved by the Food and Drug Administration for the pediatric population, findings have shown it to be effective in various clinical scenarios for sedation. In addition, recent studies show that dexmedetomidine may have promising properties for the acute treatment and prevention of tachyarrhythmias.

Short- and intermediate-term survival after extracorporeal membrane oxygenation in children with cardiac disease.

OBJECTIVES: In children with cardiac disease, common indications for extracorporeal membrane oxygenation (ECMO) include refractory cardiopulmonary resuscitation (E-CPR), failure to separate from cardiopulmonary bypass (OR-ECMO), and low cardiac output syndrome (LCOS-ECMO). Despite established acceptance, ECMO outcomes are suboptimal with a survival between 38% and 55%. We evaluated factors associated with significantly increased survival in cardiac patients requiring ECMO. METHODS: We conducted a retrospective investigation of consecutive patients undergoing ECMO between 2006 and 2010. Demographic, pre-ECMO, ECMO, and post-ECMO parameters were analyzed. Neurologic outcomes were assessed with the pediatric overall performance category scale at the latest follow-up. RESULTS: There were 3524 admissions, 95 (3%) of which necessitated ECMO; 40 (42%) E-CPR, 31 (33%) OR-ECMO, and 24 (25%) LCOS-ECMO. The overall hospital survival was 73%. The within-groups hospital survival was 75% in E-CPR, 77% OR-ECMO and 62% LCOS-ECMO. In the multivariable logistic regression analysis, chromosomal anomalies (odds ratio [OR], 8; 95% confidence interval [CI], 2-35), single ventricle (OR ,6; 95% CI, 3-33), multiple ECMO runs (OR, 15; 95% CI, 4-42), higher 24-hour ECMO flows (OR, 8; 95% CI, 4-22), decreased lung compliance (OR, 5; 95% CI, 2-16), and need for plasma exchange (OR, 5; 95% CI, 3-18) were all significant factors associated with mortality. From the univariate analysis, a common parameter associated with mortality within all groups was intracranial hemorrhage. At 1.9 years (0.9, 2.9) of follow-up, 66% were still alive, and 89% of survivors had normal function or only mild neurodevelopmental disability. CONCLUSIONS: ECMO was successfully used in children with cardiac disease with 73% and 66% short- and intermediate-term survival, respectively. The majority of the survivors had normal function or only a minimal neurodevelopmental deficit.

Dexmedetomidine: therapeutic use for the termination of reentrant supraventricular tachycardia.

OBJECTIVES: The current drug of choice for reentrant supraventricular tachycardia (SVT) is adenosine followed by verapamil or diltiazem. Although limitations and significant adverse events have been encountered over the years, an alternative effective and safe agent has not been available. Dexmedetomidine has recently been shown to have potential antiarrhythmic effects, and here we describe our experience in the acute termination of reentrant SVT. DESIGN: Retrospective case series. SETTING: Quaternary University Children's Hospital, Cardiac Intensive Care Unit. PATIENTS: Patients who received dexmedetomidine for SVT in the past 5 years. INTERVENTIONS: None. OUTCOME MEASURES: SVT episodes terminated with dexmedetomidine were compared with episodes terminated with adenosine. RESULTS: Fifteen patients, median age of 10 days (6-16), were given 27 doses of dexmedetomidine, mean dose 0.7 ± 0.3 mcg/kg, for a total of 27 episodes of SVT. Successful termination occurred in 26 episodes (96%) at a median time of 30 seconds (20-35). Duration of sinus pause was 0.6 ± 0.2 seconds, there was one episode of hypotension and no bradycardia and sedation lasted for 34 ± 8 minutes. Five patients received 27 doses of adenosine, with an overall successful cardioversion in 17 patients (63%) (P= .0017). Transient bradycardia and hypotension was seen in three patients (11%), agitation in 16 patients (59%), and broncospasm in one patient. Median sinus pause was 2.5 seconds (2-9) (P < .001). CONCLUSIONS: Dexmedetomidine appears to have novel antiarrhythmic properties for the acute termination of reentrant SVT. Although adenosine is very effective, dexmedetomidine may prove to possess a more favorable therapeutic profile with increased effectiveness and fewer side effects.

Neurodevelopmental Outcomes after Pediatric Cardiac ECMO Support.

PURPOSE: To characterize the neurodevelopmental outcomes and identify factors associated with poor outcomes in pediatric patients undergoing cardiac extracorporeal membrane oxygenation (ECMO). METHODS: Five year retrospective review, including demographics, cardiac lesion, and surgical complexity, reason for ECMO, ECMO complications, and neurodevelopmental status at discharge and latest follow-up. Neurodevelopmental status was determined through the Pediatric Overall Performance Category and Pediatric Cerebral Performance Category Scales. RESULTS: Overall ECMO survival was 73% at hospital discharge and 66% a t the latest follow-up. Most patients underwent cardiopulmonary resuscitation (CPR) (43%), and the majority (53%) had a significant disease complexity (Aristotle = 4). Complications occurred in 42% of the ECMO runs, of which 12% were intracranial injuries. At hospital discharge, 75% of patients had normal to mild disability, improving to 81% at 2 years follow-up. At hospital discharge, moderate to severe disability was associated with CPR, plasma exchange or intracranial insults. After discharge, 23% showed improvement in neurologic status and 4% showed deterioration. Cerebral infarction was the only parameter associated with deterioration at the later follow-up stage. CONCLUSION: Extracorporeal membrane oxygenation was successfully used in children with cardiac disease with 73 and 66% short and long-term survival respectively. Majority of the survivors had normal to mild neurodevelopmental disability and a significant portion showed neurologic improvement by the latest follow-up. Nevertheless, despite the grossly favorable outcomes standardized comprehensive neuropsychological testing is of paramount importance in all these patients.

Preoperative management in patients with single-ventricle physiology.

OBJECTIVE: Advancements in the preoperative management of patients with single-ventricle physiology continue to evolve. Previous reports have questioned the benefit of using inhaled nitrogen in single-ventricle patients, suggesting that this therapeutic modality may not provide adequate systemic cardiac output. The objective of this study was to review our institutional experience managing preoperative patients with single-ventricle physiology using a combination of afterload reduction and inhaled hypoxemic therapy. DESIGN, SETTING, AND PATIENTS: This is a retrospective review of 49 consecutive single-ventricle patients admitted preoperatively between July 2004 and January 2009, to the cardiac intensive care unit at Children's Hospital of Pittsburgh who underwent single-ventricle palliation, and treated preoperatively with milrinone and inhaled nitrogen. Therapeutic interventions and indirect indicators of cardiac output were collected on day of admission (time 0) and compared with those collected on the morning of surgery (time 1); data included clinical assessment, hemodynamic measurements, and laboratory values. RESULTS: When comparing time 0 to time 1, there was a statistically significant decrease in lactate (from 2.2 to 1.8 mEq/L [P < 0.001]) and an increase in pH (from 7.36 to 7.41 [P < 0.001]), serum bicarbonate (from 24.16 to 27.55 mmol/L [P < 0.001]) and arterial PaO2 (from 38.10 to 41.82 mm Hg [P = 0.027]). Preoperatively, there were no deaths, and only two patients had an evidence of multiorgan dysfunction on day of surgery (time 1). CONCLUSION: Our results suggest that a combination of afterload reduction and hypoxemic therapy was able to maintain an appropriate distribution of the cardiac output in the majority of preoperative patients with single-ventricle physiology. An adequate balance of systemic and pulmonary blood flow was successfully achieved with an increase in arterial PaO2 values.

Critical congenital heart disease--utility of routine screening for chromosomal and other extracardiac malformations.

Objective. Infants with critical congenital heart disease (CHD) can have genetic and other extracardiac malformations, which add to the short- and long-term risk of morbidity and perhaps mortality. We sought to examine our center's practice of screening for extracardiac anomalies and to determine the yield of these tests among specific cardiac diagnostic categories. Design. Retrospective review of infants admitted to the cardiac intensive care unit with a new diagnosis of CHD. Subjects were categorized into six groups: septal defects (SD), conotruncal defects (CTD), single-ventricle physiology (SV), left-sided obstructive lesions (LSO), right-sided obstructive lesions (RSO), and "other" (anomalous pulmonary venous return, Ebstein's anomaly). Screening modalities included genetic testing (karyotype and fluorescent in situ hybridization for 22q11.2 deletion), renal ultrasound (RUS), and head ultrasound (HUS). Results. One hundred forty-one patients were identified. The incidence of cardiac anomalies was: CTD (36%), SD (18%), SV (18%), LSO (14%), RSO (3%), and "other" (8%). Overall 14% had an abnormal karyotype, 5% had a deletion for 22q11.2, 28% had an abnormal RUS and 22% had abnormal HUS. Patients in SD and SV had the highest incidence of abnormal karyotype (36% and 17%); 22q11.2 deletion was present only in CTD and LSO groups (9% and 7%, respectively); abnormal RUS and HUS were seen relatively uniformly in all categories. Premature infants had significantly higher incidence of renal 43% vs. 24%, and intracranial abnormalities 46% vs. 16%. Conclusion. Infants with critical CHD and particularly premature infants have high incidence of genetic and other extracardiac anomalies. Universal screening for these abnormalities with ultrasonographic and genetic testing maybe warranted because early detection could impact short and long-term outcomes.

Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations.

BACKGROUND: Postoperative tachyarrhythmias remain a common complication after congenital cardiac operations. Dexmedetomidine (DEX), an α-2 adrenoreceptor agonist, can have a therapeutic role in supraventricular tachyarrhythmias for cardioversion to sinus rhythm or heart rate control. Whether routine perioperative use of DEX decreases the incidence of supraventricular and ventricular tachyarrhythmias was studied. METHODS: In this prospective cohort study, 32 pediatric patients undergoing cardiothoracic operations received DEX and were compared with 20 control patients who did not receive DEX. RESULTS: Dexmedetomidine was started after anesthesia induction and continued intraoperatively and postoperatively for 38±4 hours (mean dose, 0.76±0.04 µg/kg/h). Ten control patients and 2 DEX patients sustained 16 episodes of tachyarrhythmias (p=0.001), including a 25% vs 0% (p=0.01) incidence of ventricular tachycardia and 25% vs 6% (p=0.05) of supraventricular arrhythmias in the control and DEX group, respectively. Transient complete heart block occurred in 2 control patients and in 1 DEX patient. Control patients had a higher heart rate (141±5 vs 127±3 beats/min, p=0.03), more sinus tachycardia episodes (40% vs 6%; p=0.008), required more antihypertensive drugs with nitroprusside (20±7 vs 4±1 µg/kg; p=0.004) and nicardipine (13±5 vs 2±1 µg/kg; p=0.02), and required more fentanyl (39±8 vs 19±3 µg/kg; p=0.005). CONCLUSIONS: Perioperative use of dexmedetomidine is associated with a significantly decreased incidence of ventricular and supraventricular tachyarrhythmias, without significant adverse effects.

Kounis syndrome or allergic coronary vasospasm in a two-year-old.

Kounis syndrome is coronary vasospasm because of mast cell degranulation in the context of an allergic reaction. The syndrome has known associations with several drugs used during anesthesia, including rocuronium and isoflurane. In this case report, we discuss a 2-year-old patient who developed signs and symptoms of an acute coronary syndrome soon after anesthesia for atrial septal defect repair. A diagnostic angiography after the episode revealed diffusely small coronary arteries. Subsequent angiography after clinical improvement showed essentially normal coronary anatomy. We report the clinical course of this patient and postulate that Kounis syndrome was the explanation for his transient coronary vasospasm. To date, this is the youngest known patient with reported Kounis syndrome.

Diagnosis of abnormal diaphragm motion after cardiothoracic surgery: ultrasound performed by a cardiac intensivist vs. fluoroscopy.

OBJECTIVES: Abnormal diaphragmatic motion secondary to phrenic nerve injury is not uncommon after pediatric cardiothoracic surgery. Fluoroscopy is the most frequent method of diagnosis but it carries risks associated with transportation of critically ill children and exposure to ionizing radiation. Ultrasonography, a reliable diagnostic method in adults, eliminates both concerns. Since most cardiac intensivists are trained in echocardiography, we tested the hypothesis that chest ultrasound performed by a cardiac intensivist is faster than fluoroscopy, and is highly accurate in predicting fluoroscopy results, therefore serving as an equally useful diagnostic test. DESIGN: Prospective study in consecutive pediatric patients with suspected abnormal diaphragmatic motion after cardiothoracic surgery. All patients underwent fluoroscopy and ultrasound study of the diaphragm. Ultrasound was performed by a pediatric cardiac intensivist and a trainee. Kappa statistic was calculated to assess concordance between both ultrasound readings. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated to assess accuracy of each ultrasound test in predicting fluoroscopy results. RESULTS: Twenty-five patients with median age 3 months (12 days-11 years) and median weight of 3.8 kg (2.5-29 kg) were included. The ultrasound diagnosis of the cardiac intensivist was perfectly accurate (100% sensitivity, specificity, and PPV and NPV) in predicting fluoroscopy results. The ultrasound performed by the trainee achieved 85.7% sensitivity, 94.4% NPV, and 100% specificity relative to fluoroscopy. The interoperator reliability of chest ultrasound was 0.89 (95% confidence interval 0.69-1). Delay between clinical suspicion and the diagnostic tests was 15 minutes (5 minutes-2.5 hours) for ultrasound and 17 hours (60 minutes-82 hours) for fluoroscopy (P < 0.001). CONCLUSIONS: Chest ultrasound performed by cardiac intensivists allows for an early and accurate diagnosis of abnormal diaphragmatic motion, as evidenced by their ability to predict fluoroscopy findings in pediatric cardiothoracic patients. Training in ultrasound-guided assessment of diaphragmatic motion should be reinforced during pediatric cardiac intensive care fellowship.

Do neonates, infants and young children need a higher dose of enoxaparin in the cardiac intensive care unit?

BACKGROUND: Thromboembolic events are a serious complication occurring in critically ill children admitted to the cardiac intensive care unit. Although enoxaparin is one of the current anticoagulants of choice, dosages in children are extrapolated from adult guidelines. Recent data suggest that this population may need a higher dose than what is currently recommended to achieve target anti-factor Xa levels. The purpose of this study was to evaluate whether children less than 2 years old admitted to the cardiac intensive care unit require a higher enoxaparin dose than that currently recommended to achieve target anti-factor Xa levels. METHODS: Retrospective chart review including patients who received enoxaparin for the treatment or prophylaxis of venous thrombosis between January, 2005 and October, 2007. Patients were classified as younger and older as well as prophylactic and therapeutic on the basis of age and enoxaparin dose, respectively. Younger patients were those 2 month old or less and older patients were those older than 2 months of age. RESULTS: A total of 31 patients were identified; 13 (42%) were 2 months or younger and 25 (81%) were postoperative patients. Ten (32%) received prophylactic and 21 (68%) received therapeutic enoxaparin doses. To achieve optimal anti-factor Xa levels, enoxaparin dose was increased in all groups and reached statistical significance in all patients except those older than 2 months who received prophylactic enoxaparin. An average of 2.8 dosage adjustments was needed. No bleeding complications were reported. CONCLUSIONS: Young children, infants, and neonates admitted to the cardiac intensive care unit required a significantly higher enoxaparin dose than that currently recommended to achieve target anti-factor Xa levels.

Electrocardiographic effects of dexmedetomidine in patients with congenital heart disease.

OBJECTIVE: Assessment of electrocardiographic (ECG) effects of dexmedetomidine. DESIGN: Prospective observational study including children 0-17 years of age with congenital heart disease (CHD) and children following cardiothoracic surgery. Patients who did not receive dexmedetomidine were used as a control group. All patients had two ECGs: one baseline, pre-dexmedetomidine (T1) and one during dexmedetomidine infusion (T2). MEASUREMENTS AND RESULTS: Fifty-one patients, median age of 0.5 years (IQR = 3.4), and 25 patients, age 0.25 (IQR = 2.9), were included in the dexmedetomidine and control groups, respectively. Forty received a dexmedetomidine-loading dose of 1 microg/kg (IQR = 0.5). At T2, the dexmedetomidine infusion was 1 microg/kg/h (IQR = 0.5). In the dexmedetomidine group, heart rate (HR) decreased from 140 +/- 22 to 115 +/- 23 (P < 0.001); PR, PRc and PR index changed from 115 +/- 28 to 122 +/- 29 ms (P = 0.01), 174 +/- 38 to 167 +/- 35 ms (P = 0.07) and 15,882 +/- 3,565 to 13,792 +/- 3,311 (P < 0.001), respectively. QRS decreased from 84 +/- 21 to 80 +/- 21 ms (P = 0.02), and QTc had no change (433 +/- 47 to 435 +/- 36 ms). When compared to the control group, none of the ECG intervals had any difference other than a trend towards lower HR (P = 0.08). Neonates and infants had a bigger drop in the HR compared to older children (P < 0.001), while other parameters were similar. At T2 none of the dexmedetomidine group patients had atrioventricular block or other arrhythmia. Four patients in the control group had accelerated junctional rhythm. CONCLUSIONS: Use of dexmedetomidine in patients with CHD and patients following cardiothoracic surgery is not associated with any significant ECG interval abnormalities other than a trend towards lower HR.