Neonatal pulmonary hypertension is associated with increased pulmonary vascular reactivity. We studied the responses of isolated porcine intrapulmonary arteries after exposure of piglets to chronic hypobaric hypoxia (CHH) from 0 to 2.5, 3 to 6, or 14 to 17 days of age. CHH inhibited the postnatal development of endothelium-dependent vasorelaxation to acetylcholine (ACh) and the calcium ionophore A-23187. Basal accumulation of guanosine 3', 5'-cyclic monophosphate (cGMP) was unaffected, but cGMP response to ACh was inhibited. Endothelium-independent relaxation to nitric oxide (NO) and zaprinast (a phosphodiesterase inhibitor) was also inhibited, but cGMP accumulation in response to these agonists was normal. The ability of sodium nitroprusside (SNP) to cause vasorelaxation and increase cGMP accumulation was unaffected. Contractile responses to potassium chloride and prostaglandin F2 alpha (PGF2 alpha) were similar to normal after exposure from birth and 3 days and were decreased in the older group, but the ability of NG-monomethyl-L-arginine acetate to increase PGF2 alpha-induced contractions decreased. Thus exposure of newborn piglets to CHH causes 1) no increase in contractile responses and 2) impairment of endothelium-dependent and -independent relaxation by impairing signal transduction mechanisms involved in the release of NO and the effectiveness of cGMP.

Moderate-quality evidence shows that use of steroids in the acute phase of KD can be associated with improved coronary artery abnormalities, shorter duration of hospital stay and a decreased duration of clinical symptoms. High-quality evidence shows reduced inflammatory marker levels. There were insufficient data available regarding incidence of adverse effects attributable to steroids, mortality and long-term (> 1 year) coronary morbidity. Certain groups, including those based in Asia, those with higher risk scores, and those receiving longer steroid treatment may have greater benefit from steroid use, especially with decreasing rates of heart problems, but more tests are needed to answer these questions. Evidence presented in this study suggests that treatment with a long course of steroids should be considered for all children diagnosed with KD until further studies are performed.

Objective: To develop a consensus management pathway for children with Paediatric Inflammatory Multisystem Syndrome - Temporally associated with SARS-CoV-2 (PIMS-TS). Design: A three-phase online Delphi process and virtual consensus meeting sought consensus over the investigation, management and research priorities from 98 multidisciplinary participants caring for children with PIMS-TS. 46 participants (47%) completed all three phases. Participants were grouped into three panels and scored each statement from 1 (disagree) to 9 (strongly agree). In phase two participants were shown their panels scores, and in phase three all panels scores. Consensus agreement was defined as ≥70% of participants in each panel scoring the statement 7-9, and <15% scoring 1-3, and consensus disagreement was the opposite of this. Statements which achieved consensus in 2/3 panels were discussed at the consensus meeting, and when ≥70% participants agreed with the statement it achieved consensus. Results: 255 statements were assessed, with consensus agreement achieved for 111 (44%), consensus disagreement for 29 (11%), and no consensus for 115 (45%). The 140 consensus statements were used to derive the consensus management pathway. Conclusions: A national consensus pathway has been developed for children suspected of having the novel syndrome PIMS-TS in a timely, cost-efficient manner, in the midst of a global pandemic. Use of a rapid online Delphi process has made this consensus process possible. Future evidence will inform updates to this guidance, which in the interim provides a solid framework to support clinicians caring for children with PIMS-TS.

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