M-ficolin concentrations in cord blood are related to circulating phagocytes and to early-onset sepsis.

INTRODUCTION: The pattern-recognition molecule M-ficolin is synthesized by monocytes and neutrophils. M-ficolin activates the complement system in a manner similar to mannan-binding lectin (MBL), but little is known about its role in host defense. Neonates are highly vulnerable to bacterial sepsis, in particular, due to their decreased phagocytic function. RESULTS: M-ficolin cord blood concentration was positively correlated with the absolute phagocyte count (ρ 0.51, P < 0.001) and with immature/total neutrophil ratio (ρ 0.34, P < 0.001). When comparing infants with sepsis and controls, a high M-ficolin cord blood concentration (>1,000 ng/ml) was associated with early-onset sepsis (EOS) (multivariate odds ratio 10.92, 95% confidence interval 2.21-54.02, P = 0.003). Experimental exposure of phagocytes isolated from adult donors to Escherichia coli resulted in a significant time- and dose-dependent release of M-ficolin. DISCUSSION: In conclusion, M-ficolin concentrations were related to circulating phagocytes and EOS. Our results indicate that bacterial sepsis can trigger M-ficolin release by phagocytes. Future studies should investigate whether M-ficolin may be used as a marker of neutrophil activation during invasive infections. METHODS: We investigated M-ficolin in 47 infants with culture-positive sepsis during the first 30 days of life (13 with EOS and in 94 matched controls. M-ficolin was measured in cord blood using time-resolved immunofluorometric assay (TRIFMA). Multivariate logistic regression was performed.

Rapid assessment of cerebral autoregulation by near-infrared spectroscopy and a single dose of phenylephrine.

Rapid bedside determination of cerebral blood pressure autoregulation (AR) may improve clinical utility. We tested the hypothesis that cerebral Hb oxygenation (HbDiff) and cerebral Hb volume (HbTotal) measured by near-infrared spectroscopy (NIRS) would correlate with cerebral blood flow (CBF) after single dose phenylephrine (PE). Critically ill patients requiring artificial ventilation and arterial lines were eligible. During rapid blood pressure rise induced by i.v. PE bolus, ΔHbDiff and ΔHbTotal were calculated by subtracting values at baseline (normotension) from values at peak blood pressure elevation (hypertension). With the aid of NIRS and bolus injection of indocyanine green, relative measures of CBF, called blood flow index (BFI), were determined during normotension and during hypertension. BFI during hypertension was expressed as percentage from BFI during normotension (BFI%). Autoregulation indices (ARIs) were calculated by dividing BFI%, ΔHbDiff, and ΔHbTotal by the concomitant change in blood pressure. In 24 patients (11 newborns and 13 children), significant correlations between BFI% and ΔHbDiff (or ΔHbTotal) were found. In addition, the associations between Hb-based ARI and BFI%-based ARI were significant with correlation coefficients of 0.73 (or 0.72). Rapid determination of dynamic AR with the aid of cerebral Hb signals and PE bolus seems to be reliable.

Patent arterial duct, bottle-meal, and fatal myocardial ischaemia.

A patent arterial duct in pre-term neonates is frequent. Systemic complications consecutive to left-to-right shunting are well known but fatal myocardial ischaemia has not been described till now. The presented premature baby died from catecholamine refractory cardiogenic shock. Autoptic examination revealed acute ischaemic changes predominantly in the inner third of myocardium, speaking of coronary hypoperfusion due to a steal phenomenon secondary to the patent arterial duct.

Reproducibility of the blood flow index as noninvasive, bedside estimation of cerebral blood flow.

OBJECTIVE: To investigate the feasibility and reproducibility of the blood flow index (BFI) method for measuring cerebral blood flow. DESIGN AND SETTING: Prospective functional study in pediatric intensive care. PATIENTS AND PARTICIPANTS: 14 consecutive patients with median age of 2 months (range 1 days-11 years) requiring artificial ventilation, invasive arterial blood pressure monitoring, and central venous access. INTERVENTIONS: The first passage of an intravenous indocyanine green (ICG) bolus through the cerebral vasculature was monitored by noninvasive near-infrared spectroscopy. BFI was calculated by dividing maximal ICG absorption change by rise time. Reproducibility was evaluated by six ICG injections at 5-min intervals. RESULTS: Of all ICG injections 6% were canceled, and 4% were eliminated due to injection failures. Median BFI of 17 reproducibility determinations was 71 (range 12-213) and median coefficient of variation (CV) of BFI was 10% (4.9-18.5). The quantity of ICG bolus did not affect the CV (0.1 vs. 0.3 mg ICG/kg). Eight reproducibility tests in patients after cardiac surgery had smaller CV than the others, and the eight in newborns had higher CV than in older children. Patient parameters such as arterial blood pressure, endtidal CO(2), and percutaneous oxygen saturation were stable and showed CV below 2% during reproducibility determination. CONCLUSIONS: The BFI method allows rapid and repeated measurements of CBF with good feasibility and reproducibility. As a relative but not absolute measure of CBF, BFI seems to be suited for clinical evaluation of intraindividual CBF changes during determination of cerebrovascular reactivities or during therapeutic interventions.

Dynamic cerebral autoregulatory response to blood pressure rise measured by near-infrared spectroscopy and intracranial pressure.

OBJECTIVES: Noninvasive near-infrared spectroscopy (NIRS) continuously monitors changes in cerebral hemoglobin saturation (Hb(Diff) ) and content (Hb(Total)). It may allow visualization of the dynamic cerebral autoregulatory response to rapid blood pressure increases without relevant contamination of the NIRS signal from extracerebral hemoglobin. DESIGN: Prospective cohort study. SETTINGS: Multidisciplinary pediatric intensive care unit. PATIENTS: Six consecutive children in coma due to severe encephalopathy (head trauma, five patients; mumps encephalitis, one patient) requiring artificial ventilation, invasive arterial blood, and intracranial pressure monitoring. INTERVENTIONS: Frontotemporal recording of Hb(Diff) and Hb(Total) while rapidly elevating blood pressure by bolus injection of phenylephrine. MEASUREMENTS AND RESULTS: During an increase of blood pressure of 13 +/- 1 mm Hg with a "rise time" of 16 +/- 1 secs (mean of a total of 31 injections +/- sem), a significant linear correlation was found between Hb(Diff) and intracranial pressure signals (mean coefficient, 0.46 +/- 0.04) but not between Hb(Total) and intracranial pressure. Three response patterns were observed. First, Hb(Diff) and intracranial pressure reduction, corresponding with vasoconstriction and normal dynamic autoregulation (n = 3); second, Hb(Diff) and intracranial pressure increase, corresponding with persistent vasodilation and abolished autoregulation (n = 11); and third, transient Hb(Diff) and intracranial pressure increase followed by a decrease at peak blood pressure elevation, called impaired autoregulation (n = 15). In one patient with fatal brain swelling, phenylephrine testing showed no effect on NIRS signals (n = 2). Furthermore, there were significant correlations between 31 pooled interindividual pairs of Hb(Diff) changes with intracranial pressure changes (values at baseline averaged over 60 secs subtracted from values at peak blood pressure elevation averaged over 5 secs), with a correlation coefficient of .82 (p <.001). CONCLUSIONS: NIRS represents a new and promising technique for bedside determination of dynamic cerebral autoregulation during acutely induced blood pressure rise. The significant correlations found between NIRS signals and intracranial pressure excluded relevant extracerebral contamination of the NIRS signals. In our patients with severe encephalopathy, dynamic autoregulation was in most instances not fully preserved.

Neuroprotection of creatine supplementation in neonatal rats with transient cerebral hypoxia-ischemia.

We hypothesized that creatine (Cr) supplementation would preserve energy metabolism and thus ameliorate the energy failure and the extent of brain edema seen after severe but transient cerebral hypoxia-ischemia (HI) in the neonatal rat model. Six-day-old (P6) rats received subcutaneous Cr monohydrate injections for 3 consecutive days (3 g/kg body weight/day), followed by 31P-magnetic resonance spectroscopy (MRS) at P9. In a second group, P4 rats received the same Cr dose as above for 3 days prior to unilateral common carotid artery ligation followed 1 h later by 100 min of hypoxia (8% O2) at P7. Rats were maintained at 37 degrees C rectal temperature until magnetic resonance imaging was performed 24 h after HI. Cr supplementation for 3 days significantly increased the energy potential, i.e. the ratio of phosphocreatine to beta-nucleotide triphosphate (PCr/betaNTP) and PCr/inorganic phosphate (PCr/Pi) as measured by 31P-MRS. Rats with hemispheric cerebral hypoxic-ischemic insult that had received Cr showed a significant reduction (25%) of the volume of edemic brain tissue compared with controls as calculated from diffusion-weighted images (DWI). Thus, prophylactic Cr supplementation demonstrated a significant neuroprotective effect 24 h after transient cerebral HI. We hypothesize that neuroprotection is probably due to the availability of a larger metabolic substrate pool leading to a reduction of the secondary energy failure because DWI has been reported to correlate with the PCr/Pi ratio in the acute phase of injury. Additional protection by Cr may be related to prevention of calcium overload, prevention of mitochondrial permeability transition pore opening and direct antioxidant effects.

Early postoperative arrhythmias after open-heart procedures in children with congenital heart disease.

OBJECTIVE: Evaluation of occurrence, clinical course, necessity of treatment, and outcome of early postoperative cardiac arrhythmias after open-heart surgery. DESIGN: Prospective study. SETTING: Tertiary pediatric intensive care and pediatric cardiology unit. PATIENTS: All consecutive pediatric patients undergoing cardiac surgery on cardiopulmonary bypass were studied for the occurrence of cardiac arrhythmias during the whole perioperative hospital stay. Measurements: All patients had continuous electrocardiographic monitoring (with memory function) during the whole intensive care stay. A 24-hr Holter recording was done thereafter in patients with arrhythmias. RESULTS: Of 310 patients studied, 83 (27%) had postoperative arrhythmias. The occurrence rate was not different whether surgical access was by atriotomy or ventriculotomy (26% vs. 28%, respectively). Infants (39%) and cyanotic patients (36%) had a higher occurrence rate of arrhythmias (p <.05). Arrhythmias were more common after prolonged cardiopulmonary bypass time and with higher postoperative maximum troponin serum levels. In addition, patients with hemodynamically significant residual findings after correction had an increased occurrence rate of arrhythmias (18 of 43; 42%; p <.01). Of the 83 children with arrhythmias, 53 (64%) required specific antiarrhythmic treatment. The use of antiarrhythmic drugs was required in only 7 of these patients. Only one patient (1.2% of patients with arrhythmias) died from arrhythmia. No major complications resulting from arrhythmias occurred during the postoperative clinical course in the other patients. CONCLUSIONS: Although they occur frequently, postoperative arrhythmias after open-heart procedures in children are associated with low morbidity and mortality.