Spinal cord anomalies in children with anorectal malformations: Ultrasound is a good screening test.

PURPOSE: The purpose of this study is to correlate spinal ultrasound (US) and magnetic resonance imaging (MRI) findings in patients with anorectal malformations (ARMs). METHODS: A retrospective analysis of records was performed for children with ARM presenting to two major pediatric hospitals between 2009 and 2017. The primary outcome analyzed was detection of spinal cord anomalies. Spinal US was performed up to 4 months and MRI within the first year of life. The conus medullaris was considered normal if it had a tapering contour and terminated at or above the Lumbar 2-3 disk space. RESULTS: One hundred ninety-three patients with ARM presented during the study period with a slight male preponderance (108, 56%). Spinal imaging was performed in 157(82%) - 137(87%) had US, 64(41%) had MRI and 44 (28%) had both. Of the 44 who had both; US was abnormal in 25 children-confirmed by MRI in 20 (80%). US was normal in 17 children- MRI showed a filum cyst in 1 and a lipoma in 2 children and was inconclusive in 2 children (p<0.001). All who required surgery except one child, were reported on spinal US to have a low lying cord, borderline low cord or tethered cord (p<.05). No child who was reported to have a normal spinal US required de-tethering at a later stage. Spinal US had an overall sensitivity of 91% and specificity of 75% compared to MRI for detecting spinal cord anomalies in children with ARM CONCLUSIONS: Spinal US performed in a tertiary pediatric imaging department was a good screening test for spinal cord anomalies in children with ARM. The finding of a low, borderline low or tethered cord on US mandates an MRI to confirm the findings and correlates with the need for operative correction of spinal cord tethering. STUDY TYPE: Clinical research paper. LEVEL OF EVIDENCE: 2.

Cardiovascular Alterations and Multiorgan Dysfunction After Birth Asphyxia.

The cardiovascular response to asphyxia involves redistribution of cardiac output to maintain oxygen delivery to critical organs such as the adrenal gland, heart, and brain, at the expense of other organs such as the gut, kidneys and skin. This redistribution results in reduced perfusion and localized hypoxia/ischemia in these organs, which, if severe, can result in multiorgan failure. Liver injury, coagulopathy, bleeding, thrombocytopenia, renal dysfunction, and pulmonary and gastrointestinal injury all result from hypoxia, underperfusion, or both. Current clinical therapies need to be considered together with therapeutic hypothermia and cardiovascular recovery.

Correction: Single Sustained Inflation followed by Ventilation Leads to Rapid Cardiorespiratory Recovery but Causes Cerebral Vascular Leakage in Asphyxiated Near-Term Lambs.

[This corrects the article DOI: 10.1371/journal.pone.0146574.].

The cardiovascular response to birth asphyxia is altered by the surrounding environment.

BACKGROUND: A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. METHODS: Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. RESULTS: Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water (-34±2%) and warm water (-25±4%) compared with those in air (-11±5%; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). CONCLUSIONS: The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.

Single Sustained Inflation followed by Ventilation Leads to Rapid Cardiorespiratory Recovery but Causes Cerebral Vascular Leakage in Asphyxiated Near-Term Lambs.

BACKGROUND: A sustained inflation (SI) rapidly restores cardiac function in asphyxic, bradycardic newborns but its effects on cerebral haemodynamics and brain injury are unknown. We determined the effect of different SI strategies on carotid blood flow (CaBF) and cerebral vascular integrity in asphyxiated near-term lambs. METHODS: Lambs were instrumented and delivered at 139 ± 2 d gestation and asphyxia was induced by delaying ventilation onset. Lambs were randomised to receive 5 consecutive 3 s SI (multiple SI; n = 6), a single 30 s SI (single SI; n = 6) or conventional ventilation (no SI; n = 6). Ventilation continued for 30 min in all lambs while CaBF and respiratory function parameters were recorded. Brains were assessed for gross histopathology and vascular leakage. RESULTS: CaBF increased more rapidly and to a greater extent during a single SI (p = 0.01), which then decreased below both other groups by 10 min, due to a higher cerebral oxygen delivery (p = 0.01). Blood brain barrier disruption was increased in single SI lambs as indicated by increased numbers of blood vessel profiles with plasma protein extravasation (p = 0.001) in the cerebral cortex. There were no differences in CaBF or cerebral oxygen delivery between the multiple SI and no SI lambs. CONCLUSIONS: Ventilation with an initial single 30 s SI improves circulatory recovery, but is associated with greater disruption of blood brain barrier function, which may exacerbate brain injury suffered by asphyxiated newborns. This injury may occur as a direct result of the initial SI or to the higher tidal volumes delivered during subsequent ventilation.

Circulatory responses to asphyxia differ if the asphyxia occurs in utero or ex utero in near-term lambs.

BACKGROUND: A cornerstone of neonatal resuscitation teaching suggests that a rapid vagal-mediated bradycardia is one of the first signs of perinatal compromise. As this understanding is based primarily on fetal studies, we investigated whether the heart rate and blood pressure response to total asphyxia is influenced by whether the animal is in utero or ex utero. METHODS: Fetal sheep were instrumented at ∼ 139 days of gestation and then asphyxiated by umbilical cord occlusion until mean arterial blood pressure decreased to ∼ 20 mmHg. Lambs were either completely submerged in amniotic fluid (in utero; n = 8) throughout the asphyxia or were delivered and then remained ex utero (ex utero; n = 8) throughout the asphyxia. Heart rate and arterial blood pressure were continuously recorded. RESULTS: Heart rate was higher in ex utero lambs than in utero lambs. Heart rates in in utero lambs rapidly decreased, while heart rates in ex utero lambs initially increased following cord occlusion (for ∼ 1.5 min) before they started to decrease. Mean arterial pressure initially increased then decreased in both groups. CONCLUSIONS: Heart rate response to asphyxia was markedly different depending upon whether the lamb was in utero or ex utero. This indicates that the cardiovascular responses to perinatal asphyxia are significantly influenced by the newborn's local environment. As such, based solely on heart rate, the stage and severity of a perinatal asphyxic event may not be as accurate as previously assumed.

Effect of sustained inflation duration; resuscitation of near-term asphyxiated lambs.

OBJECTIVE: The 2010 ILCOR neonatal resuscitation guidelines do not specify appropriate inflation times for the initial lung inflations in apnoeic newborn infants. The authors compared three ventilation strategies immediately after delivery in asphyxiated newborn lambs. DESIGN: Experimental animal study. SETTING: Facility for animal research. SUBJECTS: Eighteen near-term lambs (weight 3.5-3.9 kg) delivered by caesarean section. INTERVENTIONS: Asphyxia was induced by occluding the umbilical cord and delaying ventilation onset (10-11 min) until mean carotid blood pressure (CBP) was ≤22 mm Hg. Animals were divided into three groups (n=6) and ventilation started with: (1) inflation times of 0.5 s at a ventilation rate 60/min, (2) five 3 s inflations or (3) a single 30 s inflation. Subsequent ventilation used inflations at 0.5 s at 60/min for all groups. MAIN OUTCOME MEASURES: Times to reach a heart rate (HR) of 120 bpm and a mean CBP of 40 mm Hg. Secondary outcome was change in lung compliance. RESULTS: Median time to reach HR 120 bpm and mean CBP 40 mm Hg was significantly shorter in the single 30 s inflation group (8 s and 74 s) versus the 5×3 s inflation group (38 s and 466 s) and the conventional ventilation group (64 s and 264 s). Lung compliance was significantly better in the single 30 s inflation group. CONCLUSION: A single sustained inflation of 30 s immediately after birth improved speed of circulatory recovery and lung compliance in near-term asphyxiated lambs. This approach for neonatal resuscitation merits further investigation.