Paediatric and neonatal anaesthesia

This chapter discusses the anaesthetic management of the neonate, infant and child. It begins with a description of neonatal physiology, then discusses fluid management, anaesthetic equipment and the conduct of anaesthesia in children, including postoperative analgesia. Regional anaesthetic techniques in children are discussed, including caudal, epidural, spinal and regional nerve blocks. Surgical procedures covered include repair of diaphragmatic hernia; gastroschisis/exomphalos; tracheo-oesophageal fistula (TOF); patent ductus arteriosus (PDA); pyloric stenosis; intussusception; herniotomy; circumcision; hypospadias repair; orchidopexy; cleft lip and palate; congenital talipes equinovarus (CTEV); femoral osteotomy, and inhaled foreign body. It includes a discussion of paediatric sedation, paediatric medical problems, paediatric advanced life support, resuscitation of the neonate, the collapsed septic child, stabilisation of the critically ill child, and paediatric drug doses and equipment.

Developmental and reproductive physiology of small mammals at high altitude: challenges and evolutionary innovations

ABSTRACTHigh-altitude environments, characterized by low oxygen levels and low ambient temperatures, have been repeatedly colonized by small altricial mammals. These species inhabit mountainous regions year-round, enduring chronic cold and hypoxia. The adaptations that allow small mammals to thrive at altitude have been well studied in non-reproducing adults; however, our knowledge of adaptations specific to earlier life stages and reproductive females is extremely limited. In lowland natives, chronic hypoxia during gestation affects maternal physiology and placental function, ultimately limiting fetal growth. During post-natal development, hypoxia and cold further limit growth both directly by acting on neonatal physiology and indirectly via impacts on maternal milk production and care. Although lowland natives can survive brief sojourns to even extreme high altitude as adults, reproductive success in these environments is very low, and lowland young rarely survive to sexual maturity in chronic cold and hypoxia. Here, we review the limits to maternal and offspring physiology – both pre-natal and post-natal – that highland-adapted species have overcome, with a focus on recent studies on high-altitude populations of the North American deer mouse (Peromyscus maniculatus). We conclude that a combination of maternal and developmental adaptations were likely to have been critical steps in the evolutionary history of high-altitude native mammals.

Newborn Screening Samples for Diabetes Research: An Underused Resource

Inborn errors of metabolism and diabetes share common derangements in analytes of metabolic networks that are tested for in newborn screening, usually performed 48–72 h after birth. There is limited research examining the metabolic imprint of diabetes on newborn screening results. This paper aims to demonstrate the links between diabetes, biochemical genetics and newborn screening in investigating disease pathophysiology in diabetes, provide possible reasons for the lack of research in diabetes in newborn screening and offer recommendations on potential research areas. We performed a systematic search of the available literature from 1 April 1998 to 31 December 2018 involving newborn screening and diabetes using OVID, MEDLINE, Cochrane and the PROSPERO register, utilizing a modified extraction tool adapted from Cochrane. Eight studies were included after screening 1312 records. Five studies reanalyzed dried blood spots (DBS) on filter paper cards, and three studies utilized pre-existing results. The results of these studies and how they relate to cord blood studies, the use of cord blood versus newborn screening dried blood spots as a sample and considerations on newborn screening and diabetes research is further discussed. The timing of sampling of newborn screening allows insight into neonatal physiology in a catabolic state with minimal maternal and placental influence. This, combined with the wide coverage of newborn screening worldwide, may aid in our understanding of the origins of diabetes.

Is Lumbar Puncture Avoidable in Low-Risk Neonates with Suspected Sepsis?

Objective Performing lumbar punctures (LP) in all clinically suspected neonatal sepsis, as per current recommendations, results in many “negative” LPs. LPs are not without their own risks. With the intention of minimizing unnecessary LPs among neonates, we aimed to identify a subgroup at extremely low risk of developing possible meningitis so that an LP could be safely avoided in it. Study Design This was a prospective, observational, and cross-sectional study in a level III neonatal unit. We included 300 episodes, in which LP was performed for suspected sepsis. We recorded a comprehensive set of clinico-demographic variables, laboratory parameters, sickness score, organ dysfunction score, and organ localization and studied association of these factors with “definite (culture positive) or possible meningitis.” “Possible” meningitis was defined with liberal criteria, intending not to miss any meningitis. A subgroup without a single factor associated with “definite or possible meningitis” was analyzed for incidence of meningitis. Results There were 121 episodes of “definite or possible meningitis” among 300 episodes of sepsis. On unadjusted analysis, apnea, irritability, high-pitched cry, seizures, neutrophilia, high C-reactive protein (CRP), score for acute neonatal physiology and perinatal extension II (SNAPPE-II), urine output, and leukomalacia were associated with “definite or possible” meningitis (p < 0.05). On multivariate analysis, no apneas, no neutrophilia, and normal CRP were independently associated with “no definite or possible meningitis.” Nevertheless, the subgroup that had a combination of no apneas, no neutrophilia, and normal CRP (n = 118) had a 29% probability of “definite or possible meningitis.” Conclusion The lowest risk subgroup had a 29% chance of having “definite or possible” meningitis. There is no subgroup that we could identify among neonates with suspected sepsis, in which it is safe to avoid an LP. Key Points

Target Oxygen Levels and Critical Care of the Newborn

Despite our growing experience in the medical care of extremely preterm infants and critically ill neonates, there are serious gaps in the understanding and clinical application of the adaptive physiology of the newborn. Neonatal physiology is often misinterpreted and considered similar to that of adult physiology. The human psyche has been seriously influenced, both from an evolutionary and survival point of view, by the cause and effect of hypoxemia which is considered as a warning sign of impending death. Within this context, it is unimaginable for even the highly trained professionals to consider saturation as low as 65% as acceptable. However, all available data suggests that newborns can thrive in a hypoxemic environment as they are conditioned to withstand extreme low saturations in the fetal environment. An approach utilizing the benefits of the hypoxic conditioning would prompt the practice of optimal targeted oxygen saturation range in the clinical management of the newborn. Our current understanding of cyanotic congenital heart disease and the physiology of single ventricle circulation, where oxygen saturation in mid 70s is acceptable, is supported by clinical and animal studies. This article argues the need to challenge our current acceptable target oxygen saturation in the newborn and provides the reasoning behind accepting lower target oxygen levels in the critically ill newborn. Challenging the current practice is expected to open a debate paving the way to understand the risks of high target oxygen levels in the newborn compared with the benefits of permissive hypoxia in avoiding the associated morbidity and mortality of oxygen radical injury.