Infants Admitted to US Intensive Care Units for RSV Infection During the 2022 Seasonal Peak

Importance

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections (LRTIs) and infant hospitalization worldwide.

Objective

To evaluate the characteristics and outcomes of RSV-related critical illness in US infants during peak 2022 RSV transmission.

Design, Setting, and Participants

This cross-sectional study used a public health prospective surveillance registry in 39 pediatric hospitals across 27 US states. Participants were infants admitted for 24 or more hours between October 17 and December 16, 2022, to a unit providing intensive care due to laboratory-confirmed RSV infection.

Exposure

Respiratory syncytial virus.

Main Outcomes and Measures

Data were captured on demographics, clinical characteristics, signs and symptoms, laboratory values, severity measures, and clinical outcomes, including receipt of noninvasive respiratory support, invasive mechanical ventilation, vasopressors or extracorporeal membrane oxygenation, and death. Mixed-effects multivariable log-binomial regression models were used to assess associations between intubation status and demographic factors, gestational age, and underlying conditions, including hospital as a random effect to account for between-site heterogeneity.

Results

The first 15 to 20 consecutive eligible infants from each site were included for a target sample size of 600. Among the 600 infants, the median (IQR) age was 2.6 (1.4-6.0) months; 361 (60.2%) were male, 169 (28.9%) were born prematurely, and 487 (81.2%) had no underlying medical conditions. Primary reasons for admission included LRTI (594 infants [99.0%]) and apnea or bradycardia (77 infants [12.8%]). Overall, 143 infants (23.8%) received invasive mechanical ventilation (median [IQR], 6.0 [4.0-10.0] days). The highest level of respiratory support for nonintubated infants was high-flow nasal cannula (243 infants [40.5%]), followed by bilevel positive airway pressure (150 infants [25.0%]) and continuous positive airway pressure (52 infants [8.7%]). Infants younger than 3 months, those born prematurely (gestational age <37 weeks), or those publicly insured were at higher risk for intubation. Four infants (0.7%) received extracorporeal membrane oxygenation, and 2 died. The median (IQR) length of hospitalization for survivors was 5 (4-10) days.

Conclusions and Relevance

In this cross-sectional study, most US infants who required intensive care for RSV LRTIs were young, healthy, and born at term. These findings highlight the need for RSV preventive interventions targeting all infants to reduce the burden of severe RSV illness.

Tachyarrhythmias During Hospitalization for COVID-19 or Multisystem Inflammatory Syndrome in Children and Adolescents

Background Cardiac complications related to COVID-19 in children and adolescents include ventricular dysfunction, myocarditis, coronary artery aneurysm, and bradyarrhythmias, but tachyarrhythmias are less understood. The goal of this study was to evaluate the frequency, characteristics, and outcomes of children and adolescents experiencing tachyarrhythmias while hospitalized for acute severe COVID-19 or multisystem inflammatory syndrome in children. Methods and Results This study involved a case series of 63 patients with tachyarrhythmias reported in a public health surveillance registry of patients aged <21 years hospitalized from March 15, 2020, to December 31, 2021, at 63 US hospitals. Patients with tachyarrhythmias were compared with patients with severe COVID-19-related complications without tachyarrhythmias. Tachyarrhythmias were reported in 22 of 1257 patients (1.8%) with acute COVID-19 and 41 of 2343 (1.7%) patients with multisystem inflammatory syndrome in children. They included supraventricular tachycardia in 28 (44%), accelerated junctional rhythm in 9 (14%), and ventricular tachycardia in 38 (60%); >1 type was reported in 12 (19%). Registry patients with versus without tachyarrhythmia were older (median age, 15.4 [range, 10.4-17.4] versus 10.0 [range, 5.4-14.8] years) and had higher illness severity on hospital admission. Intervention for treatment of tachyarrhythmia was required in 37 (59%) patients and included antiarrhythmic medication (n=31, 49%), electrical cardioversion (n=11, 17%), cardiopulmonary resuscitation (n=8, 13%), and extracorporeal membrane oxygenation (n=9, 14%). Patients with tachyarrhythmias had longer hospital length of stay than those who did not, and 9 (14%) versus 77 (2%) died. Conclusions Tachyarrhythmias were a rare complication of acute severe COVID-19 and multisystem inflammatory syndrome in children and adolescents and were associated with worse clinical outcomes, highlighting the importance of close monitoring, aggressive treatment, and postdischarge care.

Case report and review of the literature: Successful transition from acute continuous veno-venous hemodiafiltration therapy to chronic peritoneal dialysis in a chronically ventilated child with hypoplastic left heart syndrome following fontan

Fontan palliation depends on low pulmonary vascular resistance in order to maintain pulmonary blood flow and adequate oxygenation. This physiology results in higher central venous pressures with limited renal perfusion pressure and cardiac output. Positive pressure ventilation with mechanical ventilation increases intrathoracic pressure and raises central venous pressure and can further limit pulmonary and renal perfusion. Fluid removal with intermittent hemodialysis can be challenging in Fontan patients and can cause intolerable hypotension, however the increased abdominal filling pressures during peritoneal dialysis dwells can exacerbate systemic venous hypertension seen in Fontan patients and threaten adequate pulmonary blood flow and cardiac output. Successful transition to peritoneal dialysis in a chronically ventilated patient with hypoplastic left heart syndrome, end-stage renal disease and Fontan physiology has not been described. We present details outlining the successful transition across multiple modalities of renal replacement therapy to assist other teams faced with similar challenges in chronically ventilated Fontan patients with end-stage renal disease.

Multisystem Inflammatory Syndrome in Children: Survey of Protocols for Early Hospital Evaluation and Management

OBJECTIVE

To describe the similarities and differences in the evaluation and treatment of multisystem inflammatory syndrome in children (MIS-C) at hospitals in the US.

STUDY DESIGN

We conducted a cross-sectional survey from June 16 to July 16, 2020, of US children's hospitals regarding protocols for management of patients with MIS-C. Elements included characteristics of the hospital, clinical definition of MIS-C, evaluation, treatment, and follow-up. We summarized key findings and compared results from centers in which >5 patients had been treated vs those in which ≤5 patients had been treated.

RESULTS

In all, 40 centers of varying size and experience with MIS-C participated in this protocol survey. Overall, 21 of 40 centers required only 1 day of fever for MIS-C to be considered. In the evaluation of patients, there was often a tiered approach. Intravenous immunoglobulin was the most widely recommended medication to treat MIS-C (98% of centers). Corticosteroids were listed in 93% of protocols primarily for moderate or severe cases. Aspirin was commonly recommended for mild cases, whereas heparin or low molecular weight heparin were to be used primarily in severe cases. In severe cases, anakinra and vasopressors frequently were recommended; 39 of 40 centers recommended follow-up with cardiology. There were similar findings between centers in which >5 patients vs ≤5 patients had been managed. Supplemental materials containing hospital protocols are provided.

CONCLUSIONS

There are many similarities yet key differences between hospital protocols for MIS-C. These findings can help healthcare providers learn from others regarding options for managing MIS-C.

Normal Values and Growth-Related Changes of Left Ventricular Volumes, Stress, and Strain in Healthy Children Measured by 3-Dimensional Echocardiography

Normal pediatric values of three-dimensional (3D) left ventricular (LV) volumes and strain are not well established; moreover, no reports exist of the stress-strain relation and the heart rate-corrected velocity of circumferential fiber shortening (VCFc) based upon 3D imaging in children. Three-dimensional LV datasets were obtained in pediatric patients (≤18 years of age) with structurally normal hearts. Ventricular volumes and strain components (longitudinal, GLS; circumferential, GCS; and 3D strain, 3DS) were analyzed using a commercial 3D speckle-tracking analysis package. LV mid-wall global average end-systolic fiber stress was calculated from 3D LV volumes. A total of 238 patients were included in the analysis with a median age of 13.1 years (range 0.4 to 17.9 years). Regression equations were derived for 3D volume parameters, permitting body surface area-based Z score calculation. Overall, 3DS values were more negative than GLS and GCS (mean ± SD = -33.8 ± 2.8; -27.8 ± 2.9; and -21.7 ± 3.1, respectively); only GLS varied significantly with age (r = 0.22; p <0.001). Both global average end-systolic fiber stress and 3D VCFc increased significantly with age (p <0.001 for both). Stress-adjusted 3DS and VCFc both varied with age (p <0.001 for both), consistent with increased contractility. In conclusion, 3D echocardiography may be used to calculate LV stress, strain, and volumes in pediatric patients with strong reproducibility. Among strain parameters, significant age-related changes were seen only in GLS. Both indexes of contractility investigated (3DS and VCFc indexed to wall stress) improved with age. Future studies of the 3D echocardiography stress-strain relation may yield new insights into maturational changes in myocardial contractility.

Longitudinal Assessment of the Doppler-Estimated Maximum Gradient in Patients With Congenital Valvar Aortic Stenosis Pre- and Post-Balloon Valvuloplasty

BACKGROUND

Aortic stenosis has been reported to manifest a slow rate of progression in mild disease, with a greater likelihood of progression in patients with moderate-severe disease. The natural history of the Doppler-estimated maximum gradient (DEMG) in patients after balloon aortic valvuloplasty (BAVP) has not previously been studied on a large scale.

METHODS AND RESULTS

A retrospective review was performed of 360 patients from 1984 to 2012 with aortic stenosis, providing a total of 2059 echocardiograms both before and after BAVP. Patients were excluded if they had an intervention within the first 30 days of life. The relationships between the aortic stenosis DEMG and several predictors (age at initial study, body surface area, valve morphology, and initial DEMG) were explored using linear mixed effect models. Patients with a unicommissural aortic valve had a significantly higher rate of progression compared with those with a bicommissural aortic valve (0.81 and 0.45 mm Hg/year; P<0.001). The median rate of progression in the post-BAVP group was significantly lower than the median pre-BAVP rate of progression (n=34; pre-BAVP 3.97 [1.69-8.7] mm Hg/year; post-BAVP 0.40 [-1.80 to 3.88] mm Hg/year; P<0.008). When adjusted for body surface area, there was no significant increase in the DEMG (-0.03 mm Hg/m² per year; P<0.001).

CONCLUSIONS

There is a statistically significant increase in the DEMG over time in patients with aortic stenosis. After balloon dilation, the DEMG rate of change is reduced compared with that pre-dilation. Given the effect of body surface area on DEMG progression, more frequent observation should be made during periods of rapid somatic growth.

Myocardial rescue with autologous mitochondrial transplantation in a porcine model of ischemia/reperfusion

OBJECTIVE

To demonstrate the clinical efficacy of autologous mitochondrial transplantation in preparation for translation to human application using an in vivo swine model.

METHODS

A left mini-thoracotomy was performed on Yorkshire pigs. The pectoralis major was dissected, and skeletal muscle tissue was removed and used for the isolation of autologous mitochondria. The heart was subjected to regional ischemia (RI) by temporarily snaring the circumflex artery. After 24 minutes of RI, hearts received 8 × 0.1 mL injections of vehicle (vehicle-only group; n = 6) or vehicle containing mitochondria (mitochondria group; n = 6) into the area at risk (AAR), and the snare was released. The thoracotomy was closed, and the pigs were allowed to recover for 4 weeks.

RESULTS

Levels of creatine kinase-MB isoenzyme and cardiac troponin I were significantly increased (P = .006) in the vehicle-only group compared with the mitochondria group. Immune, inflammatory, and cytokine activation markers showed no significant difference between groups. There was no significant between-group difference in the AAR (P = .48), but infarct size was significantly greater in the vehicle group (P = .004). Echocardiography showed no significant differences in global function. Histochemistry and transmission electron microscopy revealed damaged heart tissue in the vehicle group that was not apparent in the mitochondria group. T2-weighted magnetic resonance imaging and histology demonstrated that the injected mitochondria were present for 4 weeks.

CONCLUSIONS

Autologous mitochondrial transplantation provides a novel technique to significantly enhance myocardial cell viability following ischemia and reperfusion in the clinically relevant swine model.