Adverse respiratory patterns in near-term spontaneously breathing newborn lambs with elevated airway liquid volumes at birth

Introduction

Recent evidence indicates that respiratory distress (RD) in near-term infants is caused by elevated airway liquid (EL) volume at the beginning of air-breathing after birth. While the adverse effects EL volumes on newborn lung function are known, the effects on respiratory control and breathing patterns shortly after birth (<4 h) are unknown. We investigated the effects of EL volumes on cardiorespiratory function and breathing patterns in spontaneously breathing near-term newborn lambs in the first hours after birth.

Methods

At 137-8 days gestation (2-3 days prior to delivery; term ∼147 days), sterile surgery was performed on fetal sheep (n = 17) to implant catheters and blood flow probes. At 140 days, lambs were delivered via caesarean section under spinal anaesthesia. Airway liquid volumes were adjusted to mimic the level expected following vaginal delivery (∼10 ml/kg; Controls; n = 7), or elective caesarean section (∼30 ml/kg; elevated airway liquid group; EL; n = 10). Spontaneous breathing and cardiorespiratory parameters were recorded over four hours after birth. Non-invasive respiratory support with supplemental oxygen was provided if required.

Results

EL lambs required higher inspired oxygen levels (p = 0.0002), were less active (p = 0.026), fed less (p = 0.008) and had higher respiratory morbidity scores than Controls (p < 0.0001). EL lambs also displayed higher rates of breathing patterns associated with RD, such as expiratory braking and tachypnoea. These patterns were particularly evident in male EL lambs who displayed higher levels of severe respiratory morbidity (e.g., expiratory braking) than female EL lambs.

Conclusion

The study demonstrates that EL volumes at birth trigger respiratory behaviour and breathing patterns that resemble clinically recognised features of RD in term infants.

Thrombotic microangiopathy and acute kidney injury in hump-nosed viper (Hypnale species) envenoming: a descriptive study in Sri Lanka

Hump-nosed viper (Hypnale species) bites are common in Sri Lanka and a proportion of these bites lead to coagulation abnormalities and acute kidney injury (AKI). We observed thrombotic microangiopathy (TMA) among some of these patients, but its contribution to severity of AKI and other morbidities remains unknown. Thus, we report a case series of TMA following hump-nosed viper bite addressing the complications and renal out comes in Sri Lanka. This was a prospective observational study carried out at the nephrology unit, Kandy in Sri Lanka from October 2010 to October 2011 and included 11 patients with AKI following hump-nosed viper bites. All eleven cases needed renal replacement therapy (RRT) with intermittent haemodialysis for a period of 1-5 weeks. Of them, 7 patients developed TMA with evidence of microangiopathic haemolytic anaemia (MAHA), thrombocytopenia and severe anaemia needing multiple blood transfusions. They needed longer duration of RRT (range 2-5 weeks); 2 patients developed chronic kidney disease and two died during acute stage. Autopsy study found thrombosis of micro-vessels. Thrombotic microangiopathy could be a causative pathology of AKI in hump-nosed viper bite carrying poor outcome.