Successful primary use of VVDL+V ECMO with cephalic drain in neonatal respiratory failure.

OBJECTIVE: To describe the use of double-lumen venovenous (VVDL) extracorporeal membrane oxygenation (ECMO) with cephalic draining cannula (VVDL+V) as a primary approach for all neonatal respiratory diagnoses and to compare our single-center experience with data as collected in the Extracorporeal Life Support Organization (ELSO) database. STUDY DESIGN: We retrospectively reviewed all cases of ECMO for neonatal respiratory failure performed in the neonatal intensive-care unit at a large referral children's hospital, the Children's Healthcare of Atlanta at Egleston (CHOA-E). Comparisons were then made to neonatal respiratory ECMO data retrieved from the ELSO database. RESULTS: At CHOA-E 162 of 189 cases were completed with the VVDL+V approach. Survival in the VVDL+V cohort was 89.1% versus 68.7% from ELSO, P<0.001. For those complications considered, the overall risk of complication favored the CHOA-E VVDL+V group as compared with ELSO (odds ratio (OR) 0.71 (0.52-0.7)) as did the risk of neurologic complications (OR 0.29, (0.15-0.58)), including intracranial hemorrhage (OR 0.39 (0.18-0.97), P=0.011). CONCLUSION: The VVDL+V approach can be used successfully as the primary approach for ECMO for neonatal respiratory failure of various etiologies and in this single-center cohort this approach was associated with improved survival and lower rates of complication as compared with the ELSO database.

Inflammatory mediator patterns in tracheal aspirate and their association with bronchopulmonary dysplasia in very low birth weight neonates.

OBJECTIVE: Alterations in inflammatory mediators are an important finding in neonates who develop bronchopulmonary dysplasia (BPD); however, there is a lack of research examining the relationship between multiple inflammatory mediators in premature neonates and the development of BPD. This study investigated whether the distribution of 12 inflammatory mediators detected in the tracheal aspirate (TA) of neonates within 24 h of birth could differentiate between neonates who did and who did not develop BPD. STUDY DESIGN: TA samples were collected from 27 very low birth weight neonates (BPD+=11), and the concentrations of 12 biomarkers associated with BPD were determined. Linear discriminant analysis (LDA) was used to classify neonates into two outcome groups. RESULT: LDA based on the 12 measured biomarkers displayed a significant level of discriminant function (P=0.007). CONCLUSION: Using linear discriminant analysis, predictive models of BPD can be generated. Our results suggest that multiple inflammatory mediators collected within 24 h of birth may be used to classify neonates into who will and who will not develop BPD.

Methylene blue-induced hyperbilirubinemia in neonatal glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Methylene blue continues to be used in the gravid female. We report three premature neonates exposed to methylene blue that experienced severe hemolytic reactions requiring exchange transfusions. Two neonates were subsequently diagnosed with G6PD deficiency. Continued caution is warranted prior to the use of methylene blue in the gravid female.

Oligotide attenuates leukocyte-endothelial cell interaction via P-selectin in the rat mesenteric vascular bed.

A novel single stranded polydeoxyribonucleotide (oligotide) was studied for its ability to modulate leukocyte-endothelial cell interaction, by means of intravital microscopy in the rat mesenteric microvasculature. Superfusion of the rat mesentery with 50 microM NG-nitro-L-arginine methyl ester (L-NAME), caused a significant, time-dependent increase in leukocyte rolling and adherence compared to control rats superfused with Krebs-Henseleit solution. However, oligotide (15 mg/kg i.v.) consistently reduced the L-NAME-induced leukocyte rolling (62 +/- 14 vs. 23 +/- 3 cells/min; P < 0.02) and adherence (11 +/- 2 vs. 4 +/- 1 cells/100 microns length of venule P < 0.01), without altering systemic blood pressure or mesenteric venular shear rate. Moreover, immunohistochemical localization of P-selectin expression on mesenteric venules was significantly increased (P < 0.01) after exposure to L-NAME, which was significantly attenuated by oligotide (P < 0.05). Similar results were also obtained by flow cytometric analysis performed on rat platelets. Stimulation of rat platelets with L-NAME significantly (P < 0.05) increased the fluorescence intensity of P-selectin, while the concomitant treatment of isolated rat platelets with L-NAME plus oligotide significantly (P < 0.005) attenuated P-selectin fluorescence intensity. Our data demonstrate that in vivo administration of oligotide can reduce leukocyte rolling and adherence in the mesenteric rat microvasculature by attenuating P-selectin expression, and confirming the key role of nitric oxide as an important regulator of leukocyte-endothelial cell interaction.

Nitric oxide protects against leukocyte-endothelium interactions in the early stages of hypercholesterolemia.

We studied the effects of CAS1609, a nitric oxide donor, on leukocyte-endothelial interactions during the early stages of hypercholesterolemia in rat mesenteric microcirculation. Rats were randomly divided into four groups: (a) rats fed control diet, (b) rats fed control diet while receiving CAS1609, (c) rats fed a high-cholesterol (HC) diet and given C93-4845 (an inactive control compound), and (d) rats fed an HC diet and given CAS1609. Both HC groups developed significantly elevated plasma cholesterol levels compared with rats fed the control diet. Intravital microscopy of mesenteric venules revealed a significant increase in leukocyte rolling and adherence in the untreated HC rats compared with control rats (P < .01). This was significantly attenuated in the HC rats given CAS1609. The HC rats given C93-4845 also developed aortic endothelial dysfunction (ie, impaired relaxation to acetylcholine or ADP) that was significantly prevented by CAS1609 infusion (P < .02). Immunohistochemical staining of ileum demonstrated significantly enhanced localization of P-selectin and intercellular adhesion molecule-1 (ICAM-1) on venular endothelium in the untreated HC rats compared with control rats (P < .01). However, P-selectin and ICAM-1 expression were significantly attenuated in HC rats given CAS1609 (P < .05 and P < .01, respectively). Thus, hypercholesterolemia induces microvascular dysfunction characterized by loss of endothelium-derived nitric oxide, increased rolling and adherence of leukocytes, and increased expression of P-selectin and ICAM-1. Infusion of CAS1609 significantly attenuated these changes due to hypercholesterolemia. Our data suggest that nitric oxide plays a significant role in the prevention of the early endothelial dysfunction observed in hypercholesterolemia.

Beneficial effects of LEX032, a novel recombinant serine protease inhibitor, in murine traumatic shock.

The effects of LEX032, a novel recombinant serine protease inhibitor (i.e., serpin), were investigated in an experimental model of Noble-Collip drum shock. Pentobarbital-anesthetized rats subjected to drum trauma and receiving only the vehicle, developed severe traumatic shock with hypotension. These traumatized rats exhibited a survival time of 135 +/- 29 min, endothelial dysfunction, and a significant increase in intestinal myeloperoxidase activity. In contrast, LEX032 given intravenously (15 mg/kg bolus) resulted in a significant prolongation of survival time to 264 +/- 25 min (p < .01), a significant and sustained increase in mean arterial blood pressure, and a significant attenuation of intestinal myeloperoxidase activity (p < .05). Moreover, administration of LEX032 significantly preserved superior mesenteric artery (SMA) endothelial function as measured by the relaxation response of isolated (SMA) rings to acetylcholine, an endothelium-dependent vasodilator (64 +/- 10% vs. 25 +/- 6%, p < .01 compared with untreated trauma rats). Vasorelaxation responses to an endothelium-independent vasodilator, NaNO2, were unchanged in trauma. Our results indicate a significant protective role of LEX032 in traumatic shock, based on the preservation of endothelial function, reduced neutrophil accumulation in injured tissues, and increased survival time. These findings suggest that inhibition of serine proteases, some of which are from neutrophils, can be beneficial in traumatic shock in rats.

Inhibition of endothelial-derived nitric oxide promotes P-selectin expression and actions in the rat microcirculation.

BACKGROUND/AIMS: Inhibition of nitric oxide synthesis increases leukocyte and endothelial interaction in mesenteric venules. In this study, the relationship between inhibition of NO and expression of the adhesion molecule P-selectin was examined. METHODS: The rat mesentery was superfused with the NO inhibitor NG-nitro-L-arginine methyl ester (L-NAME) either alone or in combination with intravenous infusions of L-arginine, D-arginine, a P-selectin-neutralizing monoclonal antibody (PB1.3 [1 mg/kg]), recombinant human superoxide dismutase (hSOD), or 8 bromoguanosine 3',5'-cyclic monophosphate (8-br-cGMP). Leukocyte rolling and adherence were monitored in mesenteric venules via intravital microscopy. Ileal tissue superfused with L-NAME was examined immunohistochemically for P-selectin expression. RESULTS: Superfusion of the rat mesentery with L-NAME resulted in a significant increase in leukocyte rolling and adherence in the mesenteric venule, which was attenuated by administration of L-arginine but not D-arginine. Monoclonal antibody PB1.3 as well as hSOD and 8-br-cGMP administered before initiation of L-NAME superfusion significantly attenuated the increase in leukocyte rolling and adherence. Immunohistochemistry showed a significant increase in P-selectin expression after 60 minutes of superfusion with L-NAME, which was attenuated by L-arginine, hSOD, and 8-br-cGMP. CONCLUSIONS: These data indicate an important functional relationship between endothelial-derived NO production and expression of the endothelial adhesion molecule P-selectin.

Nitric oxide attenuates leukocyte-endothelial interaction via P-selectin in splanchnic ischemia-reperfusion.

We studied the effects of exogenous nitric oxide (NO) on leukocyte-endothelial interaction after 60 min of splanchnic artery ischemia and 120 min of reperfusion (SAO/R) in pentobarbital sodium-anesthetized rats via intravital microscopy. Treatment with the NO donor S-nitroso-N-acetylpenicillamine (SNAP, 20 micrograms/kg bolus followed by infusion at 20 micrograms.kg-1.h-1), beginning 10 min before reperfusion, resulted in significantly decreased leukocyte-endothelial interaction. This was manifested by a significant decrease in leukocyte rolling and adherence in the postcapillary venules. Tissue protection was demonstrated by a significantly lower plasma free amino-nitrogen concentration in the SNAP-treated SAO/R rats compared with those receiving NO-depleted SNAP (P < 0.05). Immunohistochemical localization of P-selectin showed significantly decreased P-selectin expression on the venular endothelium after SAO/R in rats given SNAP 10 min before reperfusion (23.0 +/- 3.2% vs. 54.9 +/- 12.1% positive staining, respectively, P < 0.01). From these data, we conclude that the effects of exogenous NO on leukocyte-endothelial interaction after ischemia-reperfusion appear to be at least partially mediated through the endothelial adhesion molecule P-selectin.

Role of P-selectin in microvascular leukocyte-endothelial interaction in splanchnic ischemia-reperfusion.

The role of P-selectin in leukocyte-endothelial interaction after splanchnic arterial occlusion and reperfusion (SAO/R) in pentobarbital-anesthetized rats was investigated employing a P-selectin-neutralizing monoclonal antibody (i.e., MAb PB1.3). MAb PB1.3 (1 mg/kg) given intravenously to SAO/R rats just before reperfusion significantly attenuated leukocyte rolling and adherence in mesenteric postcapillary venules as observed via intravital microscopy. Likewise, ileal myeloperoxidase (MPO) activity was decreased from 4.6 +/- 0.6 in nontreated ischemic rats to 2.0 +/- 0.2 U/100 mg (P < 0.01), indicating a lesser degree of polymorphonuclear leukocyte (PMN) accumulation. A significantly lower plasma free amino-nitrogen concentration was observed in MAb PB1.3-treated rats vs. untreated (P < 0.01), suggesting decreased tissue injury after reperfusion. Immunohistochemical localization demonstrated significant expression of P-selectin in endothelial cells lining ileal postcapillary venules 30 min after reperfusion of the ischemic splanchnic circulation. Thus P-selectin appears to plays an important role in leukocyte accumulation after splanchnic ischemia-reperfusion, and the MAb PB1.3 attenuates the accumulation of PMNs in the ischemic-reperfused small bowel, resulting in reduced tissue injury.

Beneficial actions of CP-0127, a novel bradykinin receptor antagonist, in murine traumatic shock.

We studied the effects of CP-0127, a novel bradykinin receptor antagonist, in a rat model of traumatic shock. Pentobarbital-anesthetized rats subjected to Noble-Collip drum trauma developed a shock state characterized by marked hypotension, significant increases in plasma-free amino-nitrogen (8.6 +/- 0.97 vs. 2.3 +/- 0.15 U/ml in control rats) and intestinal myeloperoxidase (MPO) activity (2.7 +/- 0.33 vs. 0.08 +/- 0.03 U/100 mg control rats, intestinal tissue), and a survival time of only 110 +/- 9 min. Moreover, superior mesenteric artery (SMA) rings isolated from rats subjected to traumatic shock relaxed to the endothelium-dependent vasodilator acetylcholine (ACh) significantly less than rings isolated from control rats (21 +/- 4 vs. 92 +/- 4%, P < 0.001). Administration of CP-0127 at a dose of 10 mg/kg subcutaneously completely blocked the hypotensive response to 2.5 micrograms/kg bradykinin injected intravenously in sham traumatic shock rats. CP-0127 given immediately posttrauma prolonged survival time to 219 +/- 27 min (P < 0.01) and attenuated the increases in plasma-free amino-nitrogen (3.7 +/- 0.41 U/ml, P < 0.01) and tissue MPO activities (1.2 +/- 0.71 U/100 mg intestinal tissue, P < 0.05). Furthermore, SMA endothelial function was significantly preserved (relaxation to ACh: 57 +/- 6%, P < 0.01) in CP-0127-treated traumatic shock rats. These results indicate that bradykinin plays an important role in tissue injury associated with traumatic shock and that CP-0127 affords significant protection, which may be achieved through inhibition of neutrophil-endothelial interaction and protection of vascular endothelial function.

Continued pulmonary recovery observed after discontinuing extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a valuable therapy for the treatment of reversible lung disease in neonates. Associated with this treatment, however, are risks for complications that increase with the duration of therapy. We evaluated alveolar-arterial oxygen tension difference P(A-a)O2 pulmonary compliance (CL), and functional residual capacity (FRC) in 20 infants immediately after ECMO was discontinued, and again 24 hours thereafter. We measured CL by pneumotachography and esophageal manometry and FRC by helium dilution. Mean (+/- SEM) values for CL and FRC increased (CL from 0.28 +/- 0.02 to 0.35 +/- 0.03 mL/cmH2O)/kg and FRC from 18.6 +/- 1.4 to 22.2 +/- 1.1 mL/kg; P < 0.05), and P(A-a)O2 and the oxygenation index (OI) decreased (200 +/- 19 to 169 +/- 14 mm Hg and 6.9 +/- 0.44 to 5.4 +/- 0.5, respectively; P < 0.02), over the 24 hour period following ECMO. Nineteen of 20 infants experienced improvement in at least two of these parameters. Improvements were found to be greatest in the infant with the worst lung function immediately after discontinuing ECMO, and in the ten infants who had not received pancuronium bromide for inducing skeletal muscle paralysis, following decannulation from ECMO. These data indicate that improvement in lung function following ECMO will generally continue over the 24 hour period following the termination of cardiopulmonary bypass, and that borderline pulmonary status may not preclude discontinuation of bypass therapy.