Cerebral pressure passivity in newborns with encephalopathy undergoing therapeutic hypothermia

We extended our recent modification of the power spectral estimation approach to quantify spectral coherence. We tested both the standard and the modified approaches on simulated data, which showed that the modified approach was highly specific and sensitive to the coupling introduced in the simulation while the standard approach lacked these features. We also applied the modified and standard approaches to quantify the pressure passivity in 4 infants receiving therapeutic hypothermia. This was done by measuring the coupling between continuous cerebral hemoglobin differences and mean arterial blood pressure. Our results showed that the modified approach identified a lower pressure passivity index (PPI, percent time the coherence was above a predefined threshold) than the standard approach (P = 0.0027)

A Multidimensional Approach to Pain Assessment in Critically Ill Infants During a Painful Procedure

Objectives: Inferring the pain level of a critically ill infant is complex. The ability to accurately extract the appropriate pain cues from observations is often jeopardized when heavy sedation and muscular blocking agents are administered. Near-infrared spectroscopy is a noninvasive method that may provide the bridge between behavioral observational indicators and cortical pain processing. We aimed to describe regional cerebral and systemic hemodynamic changes, as well as behavioral reactions in critically ill infants with congenital heart defects during chest-drain removal after cardiac surgery. Methods: Our sample included 20 critically ill infants with congenital heart defects, less than 12 months of age, admitted to the cardiac intensive care unit after surgery. Results: Cerebral deoxygenated hemoglobin concentrations significantly differed across the epochs (ie, baseline, tactile stimulus, noxious stimulus) (P=0.01). Physiological systemic responses and Face Leg Activity Cry Consolability (FLACC) pain scores differed significantly across the events (P<0.01). The 3 outcome measures were not found to be associated with each other. Mean FLACC pain scores during the painful procedure was 7/10 despite administration of morphine. Midazolam administration accounted for 36% of the variance in pain scores. Discussion: We demonstrated with a multidimensional pain assessment approach that significant cerebral, physiological, and behavioral activity was present in response to a noxious procedure in critically ill infants despite the administration of analgesic treatment. Considering that the sedating agent significantly dampened pain behaviors, assessment of cerebral hemodynamic in the context of pain seems to be an important addition.National Institutes of Health (U.S.) (Grant R01EB001659)National Institutes of Health (U.S.) (Grant K24NS057568)National Institutes of Health (U.S.) (Grant R21HD056009)National Institute for Biomedical Imaging and Bioengineering (U.S.)National Institute of Neurological Disorders and Stroke (U.S.)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.

Higher hematocrit improves cerebral outcome after deep hypothermic circulatory arrest

AbstractBackground: Various degrees of hemodilution are currently in clinical use during deep hypothermic circulatory arrest to counteract deleterious rheologic effects linked with brain injury by previous reports. Material and methods: Seventeen piglets were randomly assigned to three groups. Group I piglets (n = 7) received colloid and crystalloid prime (hematocrit < 10%), group II piglets (n = 5) received blood and crystalloid prime (hematocrit 20%), group III piglets (n = 5) received blood prime (hematocrit 30%). All groups underwent 60 minutes of deep hypothermic circulatory arrest at 15º C. with continuous magnetic resonance spectroscopy and near-infrared spectroscopy Neurologic recovery was evaluated for 4 days (neurologic deficit score 0, normal, to 500, brain death; overall performance category 1, normal, to 5, brain death). Neurohistologic score (0, normal, to 5+, necrosis) was assessed after the animals were euthanized on day 4. Results: Group I had significant loss of phosphocreatine and intracellular acidosis during early cooling (phosphocreatine in group I, 86.3% ± 26.8%; group II, 117.3% ± 8.6%; group III, 110.9% ± 2.68%; p = 0.0008; intracellular pH in group I, 6.95 ± 0.18; group II, 7.28 ± 0.04; group III, 7.49 ± 0.04; p = 0.0048). Final recovery was the same for all groups. Cytochrome aa3 was more reduced in group I during deep hypothermic circulatory arrest than in either of the other groups (group I, -43.6 ± 2.6; group II, -16.0 ± 5.2; group III, 1.3 ± 3.1; p < 0.0001). Neurologic deficit score was best preserved in group III (p < 0.05 group II vs group III) on the first postoperative day, although this difference diminished with time and all animals were neurologically normal after 4 days. Histologic assessment was worst among group I in neocortex area (group I, 1.33 ± 0.3; group II, 0.22 ± 0.1; group III, 0.40 ± 0.2, p < 0.05, group I vs group II; p = 0.0287, group I vs group III). Conclusion: Extreme hemodilution during cardiopulmonary bypass may cause inadequate oxygen delivery during early cooling. The higher hematocrit with a blood prime is associated with improved cerebral recovery after deep hypothermic circulatory arrest. (J Thorac Cardiovasc Surg 1996;112:1610-21

A novel sialyl lewis x analog attenuates cerebral injury after deep hypothermic circulatory arrest

AbstractBackground: The initial step in the inflammatory process, which can be initiated by cardiopulmonary bypass and by ischemia/reperfusion, is mediated by interactions between selectins on endothelial cells and on neutrophils. We studied the effects of selectin blockade using a novel Sialyl Lewis X analog (CY-1503) on recovery after deep hypothermic circulatory arrest in a piglet model. Methods: Twelve Yorkshire piglets were subjected to cardiopulmonary bypass, 30 minutes of cooling, 100 minutes of circulatory arrest at 15°C, and 40 minutes of rewarming. Five animals received a bolus of 60 mg/kg of CY-1503 and an infusion (3 mg/kg per hour) for 24 hours from reperfusion (group O), and 7 randomly selected control piglets received saline solution (group C). Body weight and total body water content were evaluated 3 hours and 24 hours after reperfusion by a bio-impedance technique. Neurologic recovery of animals was evaluated daily by neurologic deficit score (0 = normal, 500 = brain death) and overall performance categories (1 = normal, 5 = brain death). The brain was fixed in situ on the fourth postoperative day and examined by histologic score (0 = normal, 5+ = necrosis) in a blinded fashion. Results: Two of 7 animals in group C died. The neurologic deficit score was significantly lower in group O than in group C (postoperative day 1, P < .001; postoperative day 2, P = .02). The overall performance category was significantly lower in group O than in group C on postoperative day 2 (P = .01). Percentage total body water after cardiopulmonary bypass was significantly higher in group C than in group O (P = .03). Histologic score tended to be higher in group C than in group O, but this difference did not reach statistical significance (group O = 0.5 ± 0.7; group C = 1.3 ± 1.9). Conclusion: Blockade of selectin adhesion molecules by saturation with a Sialyl Lewisxanalog accelerates recovery after 100 minutes of deep hypothermic circulatory arrest in a piglet survival model. (J Thorac Cardiovasc Surg 1999; 117:1204-11

Cranial Ultrasound Lesions in the NICU Predict Cerebral Palsy at Age 2 Years in Children Born at Extremely Low Gestational Age

Our prospective cohort study of extremely low gestational age newborns evaluated the association of neonatal head ultrasound abnormalities with cerebral palsy at age 2 years. Cranial ultrasounds in 1053 infants were read with respect to intraventricular hemorrhage, ventriculomegaly, and echolucency, by multiple sonologists. Standardized neurological examinations classified cerebral palsy, and functional impairment was assessed. Forty-four percent with ventriculomegaly and 52% with echolucency developed cerebral palsy. Compared with no ultrasound abnormalities, children with echolucency were 24 times more likely to have quadriparesis and 29 times more likely to have hemiparesis. Children with ventriculomegaly were 17 times more likely to have quadriparesis or hemiparesis. Forty-three percent of children with cerebral palsy had normal head ultrasound. Focal white matter damage (echolucency) and diffuse damage (late ventriculomegaly) are associated with a high probability of cerebral palsy, especially quadriparesis. Nearly half the cerebral palsy identified at 2 years is not preceded by a neonatal brain ultrasound abnormality. Originally published Journal of Child Neurology, Vol. 24, No. 1, Jan 200