Best practice & research. Clinical anaesthesiology
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Pulmonary hypertension presenting in the neonatal period can be due to congenital heart malformations (most commonly associated with obstruction to pulmonary venous drainage), high output cardiac failure from large arteriovenous malformations and persistent pulmonary hypertension of the newborn (PPHN). Of these, the most common cause is PPHN. PPHN develops when pulmonary vascular resistance (PVR) remains elevated after birth, resulting in right-to-left shunting of blood through foetal circulatory pathways. ⋯ Direct pulmonary vasodilators, such as inhaled nitric oxide, have been shown to improve the outcome and reduce the need for ECMO. However, there is very limited experience with other pulmonary vasodilators. The goals for anaesthetic management are (1) to provide an adequate depth of anaesthesia to ablate the rise in PVR associated with surgical stimuli; (2) to maintain adequate ventilation and oxygenation; and (3) to be prepared to treat a pulmonary hypertensive crisis--an acute rise in PVR with associated cardiovascular collapse.
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Neonatal anaesthesia dosing needs to be based on physiological characteristics of the newborn, pharmacokinetic/pharmacodynamic considerations and the adverse effects profile. Disease processes and treatments in this group are distinct from adults. Absorption, distribution and clearance are altered because of immaturity of enzyme, anatomical or physiological systems resulting in extensive variability of drug disposition in neonates. ⋯ Although neuromuscular monitoring is robust, there remains a need for other clinically applicable tools to assess pharmacodynamics that can provide effect feedback. In neonatal anaesthesia, a specific focus of interest is tools to assess depth of anaesthesia, sedation and pain. These tools have potential to improve effectiveness and safety.
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Best Pract Res Clin Anaesthesiol · Sep 2010
ReviewTracheo-oesophageal fistula (TOF) and oesophageal atresia (OA).
Tracheo-oesophageal fistula (TOF) and oesophageal atresia (OA) represent a series of anatomical abnormalities presenting for emergency surgery in the neonatal period. They present the anaesthetist with cardio-respiratory challenges in the preoperative, intra-operative and postoperative phases. ⋯ The basic science, anatomy and genetics are discussed as well as the clinical presentation, perioperative management, controversies and complications. The evidence for optimum management is based mostly on expert opinion; there are very few large randomised controlled trials concerning many areas of perioperative management.
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Best Pract Res Clin Anaesthesiol · Sep 2010
ReviewThe impact of the perioperative period on neurocognitive development, with a focus on pharmacological concerns.
Mounting evidence from animal studies has implicated that all commonly used anaesthetics and sedatives may induce widespread neuronal cell death and result in long-term neurological abnormalities. These findings have led to serious questions regarding the safe use of these drugs in young children. In humans, recent findings from retrospective, epidemiological studies do not exclude the possibility of an association between surgery with anaesthesia early in life and subsequent learning abnormalities. ⋯ However, important questions need to be addressed before findings from laboratory studies and retrospective clinical surveys can be used to guide clinical practice. This article summarises the currently available preclinical and clinical information regarding the impact of anaesthetics, sedatives, opioids, pain and stress, inflammation, hypoxia-ischaemia, co-morbidities and genetic predisposition on brain structure and long-term neurological function. Moreover, this article outlines the putative mechanisms of anaesthetic neurotoxicity, and the phenomenon's implications for clinical practice in this rapidly emerging field.