Joan Sanchez De Toledo

Dexmedetomidine use in a pediatric cardiac intensive care unit: can we use it in infants after cardiac surgery?

Objective: To assess clinical response of dexmedetomidine alone or in combination with conventional sedatives/analgesics after cardiac surgery. Design: Retrospective study. Setting: Pediatric cardiac intensive care unit. Patients: Infants and neonates after cardiac surgery. Measurements and Main Results: We identified 80 patients including 14 neonates, at mean age and weight of 4.1 ± 3.1 months and 5.5 ± 2 kg, respectively, who received dexmedetomidine for 25 ± 13 hours at an average dose of 0.66 ± 0.26 &mgr;g·kg−1·hr−1. Overall normal sleep to moderate sedation was documented 94% of the time and no pain to mild pain for 90%. Systolic blood pressure (SBP) decreased from 89 ± 15 mm Hg to 85 ± 11 mm Hg (p = .05), heart rate (HR) from 149 ± 22 bpm to 129 ± 16 bpm (p < .001), and respiratory rate (RR) remained unchanged. When baseline arterial blood gases were compared with the most abnormal values, pH decreased from 7.4 ± 0.07 to 7.37 ± 0.05 (p = .006), Po2 from 91 ± 67 mm Hg to 66 ± 29 mm Hg (p = .005), and CO2 increased from 45 ± 8 mm Hg to 50 ± 12 mm Hg (p = .001). At the beginning of the study, 37 patients (46%) were mechanically ventilated; and at 48 hours, 13 patients (16%) were still intubated and five patients failed extubation. Three groups of patients were identified: A, dexmedetomidine only (n = 20); B, dexmedetomidine with sedatives/analgesics (n = 38); and C, dexmedetomidine with both sedatives/analgesics and fentanyl infusion (n = 22). The doses of dexmedetomidine and rescue sedatives/analgesics were not significantly different among the three groups but duration of dexmedetomidine was longer in group C vs. A (p = .03) and C vs. B (p = .002). Pain, sedation, SBP, RR, and arterial blood gases were similar. HR was higher in group C vs. B (p = .01). Comparison between neonates and infants showed that infants required higher dexmedetomidine doses, 0.69 ± 25 &mgr;g·kg−1·hr−1, and vs. 0.47 ± 21 &mgr;g·kg−1·hr−1 (p = .003) and had lower HR (p = .01), and RR (p = .009), and higher SBP (p < .001). Conclusions: Dexmedetomidine use in infants and neonates after cardiac surgery was well tolerated in both intubated and nonintubated patients. It provides an adequate level of sedation/analgesia either alone or in combination with low-dose conventional agents.

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.

Brain Dysplasia Associated with Ciliary Dysfunction in Infants with Congenital Heart Disease

OBJECTIVE To test for associations between abnormal respiratory ciliary motion (CM) and brain abnormalities in infants with congenital heart disease (CHD) STUDY DESIGN: We recruited 35 infants with CHD preoperatively and performed nasal tissue biopsy to assess respiratory CM by videomicroscopy. Cranial ultrasound scan and brain magnetic resonance imaging were obtained pre- and/or postoperatively and systematically reviewed for brain abnormalities. Segmentation was used to quantitate cerebrospinal fluid and regional brain volumes. Perinatal and perioperative clinical variables were collected. RESULTS A total of 10 (28.5%) patients with CHD had abnormal CM. Abnormal CM was not associated with brain injury but was correlated with increased extraaxial cerebrospinal fluid volume (P < .001), delayed brain maturation (P < .05), and a spectrum of subtle dysplasia including the hippocampus (P < .0078) and olfactory bulb (P < .034). Abnormal CM was associated with higher composite dysplasia score (P < .001), and both were correlated with elevated preoperative serum lactate (P < .001). CONCLUSIONS Abnormal respiratory CM in infants with CHD is associated with a spectrum of brain dysplasia. These findings suggest that ciliary defects may play a role in brain dysplasia in patients with CHD and have the potential to prognosticate neurodevelopmental risks.

Acute Compartment Syndrome in a Patient on Extracorporeal Support: Utility of Near-Infrared Spectroscopy

m ACUTE COMPARTMENT SYNDROME is a surgical emergency. Its diagnosis is based on a clinical suspicion hat includes a swollen extremity with severe pain and tenderess, loss of distal pulses, and decreased sensation. The conrmation of this diagnosis is based on the direct invasive easurement of the pressure inside this compartment. A delay n the diagnosis often is associated with a poor prognosis and uts the viability of the affected tissue in jeopardy.1 Critically ll patients supported with extracorporeal membrane oxygention (ECMO) have several conditions that potentially may elay this diagnosis. The associated use of deep sedation and uscle relaxation and the loss of pulsatile flow make this iagnosis a challenge. Near-infrared spectroscopy (NIRS) is a noninvasive method hat allows continuous monitoring of tissue oxygen saturation tSO2). NIRS technology is based on the transmission and absorption of near-infrared light at 2 different wavelengths (730 and 810 nm) that correspond to the spectral absorption of oxygenated (800 nm) and deoxygenated hemoglobin (760 nm or lower). Light in the near-infrared spectrum (700-1,100 nm) undergoes the least absorption and thus travels longer distances through biologic tissues. The analysis of light absorbencies as near-infrared light passes through the tissues allows the assessment of tissue oxygenation by calculating the concentrations of oxyand deoxyhemoglobin.2,3 NIRS technology was initially pproved for the monitoring of cerebral oxygenation, but now t is used also in the monitoring of tissue perfusion in other rgans rather than the brain.3-6 A case of lower-limb acute compartment syndrome in a 15-year-old patient on ECMO in whom NIRS technology helped to direct his care is presented.

Inhaled Pulmonary Vasodilators: Are There Indications Within the Pediatric ICU?

Inhaled nitric oxide (INO) is only FDA-cleared for neonates (> 34 weeks gestation) with hypoxic respiratory failure-associated pulmonary hypertension. Off-label use of INO is common in the pediatric population despite a lack of evidence regarding survival benefit, questioning whether the therapy should be considered outside the neonatal period. A lack of definitive evidence combined with increasing health-care costs has led to the use of less costly inhaled prostacyclin as an alternative to INO, presenting unique patient safety concerns. We evaluate the current evidence and patient safety considerations regarding inhaled pulmonary vasodilators in the pediatric population.

Structural network topology correlates of microstructural brain dysmaturation in term infants with congenital heart disease

Neonates with complex congenital heart disease (CHD) demonstrate microstructural brain dysmaturation, but the relationship with structural network topology is unknown. We performed diffusion tensor imaging (DTI) in term neonates with CHD preoperatively (N = 61) and postoperatively (N = 50) compared with healthy term controls (N = 91). We used network topology (graph) analyses incorporating different weighted and unweighted approaches and subject‐specific white matter segmentation to investigate structural topology differences, as well as a voxel‐based analysis (VBA) to confirm the presence of microstructural dysmaturation. We demonstrate cost‐dependent network inefficiencies in neonatal CHD in the pre‐ and postoperative period compared with controls, related to microstructural differences. Controlling for cost, we show the presence of increased small‐worldness (hierarchical fiber organization) in CHD infants preoperatively, that persists in the postoperative period compared with controls, suggesting the early presence of brain reorganization. Taken together, topological microstructural dysmaturation in CHD infants is accompanied by hierarchical fiber organization during a protracted critical period of early brain development. Our methodology also provides a pipeline for quantitation of network topology changes in neonates and infants with microstructural brain dysmaturation at risk for perinatal brain injury.

82: MORTALITY AND INCIDENCE OF ACUTE ADVERSE NEUROLOGIC EVENTS IN THE CARDIAC INTENSIVE CARE UNIT

Crit Care Med 2015 • Volume 43 • Number 12 (Suppl.) models were used to assess which predictors significantly and independently predicted a significant thrombotic event and significant bleeding. Results: All four measures showed good discrimination – RCK (AUC=0.81, p<0.01), Anti factor Xa (AUC=0.79, p<0.01), aPTT (AUC=0.68, p=0.02) and ACT (AUC=0.64, p=0.03) for a thrombotic event. However, Anti-Xa (OR=0.62, 95% CI 0.53– 0.72, p<0.001) and RCK (OR=1.19, 95% CI 1.07–1.34, p=0.003) were the only independent predictors of a significant thrombotic event (ACT and aPTT fell out of the model). However, none of the measures showed good discrimination for significant bleeding or independently predicted significant bleeding. Conclusions: Anti factor Xa and RCK appear to be stronger indicators than ACT or aPTT for predicting risk of a significant thrombotic event during ECMO support. Further studies need to be conducted in ECMO patients to determine indicators for bleeding.