Monitoring during paediatric cardiac anaesthesia

Abstract

Monitoring of paediatric anaesthesia has become increasingly more complex in recent years (precordial, oesophageal or paratracheal). Specialized monitoring includes the monitoring of mixed venous oxygenation saturation (S~O2) which is being increasingly used within the critical care area. Transoesophageal echocardiography (TOE) has become accepted in adult cardiac surgery particularly in the fields of mitral valve repair and aortic root surgery, where it allows immediate assessment of the adequacy of repair. The place of TOE in congenital heart disease is now becoming more clearly defined. Cerebral function monitoring is an area of a great deal of research and several new monitoring methods are under review. The use of the thromboelastogram in monitoring coagulation has been found to decrease blood and fluid replacement during liver transplantation and its use during cardiac surgery is increasing. Other end organs that are affected by cardiopulmonary bypass (CPB) include the gut; liver and immune system, possibly leading to multi-organ failure in some cases, and interest is being shown in their monitoring.The purpose of this review is to present the recent publications relating to specific areas of both standard and specialized monitoring and indicate areas where these monitors may prove particularly useful to the practitioner involved in the care of paediatric cardiac patients. Routine monitoring ElectrocardiogramThe ECG displays the electrical activity of the heart. Abnormalities in the ECG can reflect alterations in rate or rhythm and changes in the ST segment may incidate underlying ischaemia. The normal ECG in childhood changes with age and shows several differences from the adult, particularly in the first few years of life where the right ventrical mass is dominant. There are several general changes that occur with increasing age (Table I). Heart rate (HR), frontal plane QRS vector (axis), PR interval, R wave heights and T waves are some of the factors that alter with age (Table II) and the reader is referred to a more specialized review for further information. 1,2 In adult cardiac surgery there has been investigation of perioperative myocardial ischaemia, its prognosis, and the best way of detecting it. 3,4 In children, however, there has been little work looking at the ST segment. Bell et al. ~ reported three cases of ST changes in neonates consistent with myocardial ischaemia. The first case involved a child of 26 wk who developed ST changes during awake laryngoscopy and lung retraction that were presumed to be related to myocardial hypoxia, although pulse oximetry readings were not mentioned. In the second case, ST changes improved on starting trinitroglycerine, isoproterenol and dopamine and in the third were related to ectiocardiographic changes. Cherian and Rao 6 associate the ST segment with the adequacy of coronary blood flow during the arterial switch operation for transposition. Observing leads I and V 5 for the left coronary and lead II for the right, greater than 1 mm elevation for more tha...

The hemodynamic effects of newborn caudal anesthesia assessed by transthoracic echocardiography: a randomized, double‐blind, controlled study

“…Nevertheless, the hemodynamic alterations induced by caudal anesthesia in neonates have not been thoroughly investigated. In the past, thermodilation method was used to measure the hemodynamic changes and this technique is very difficult to apply in very young children (1). This explains why there is a lack of information concerning the hemodynamic alterations after caudal anesthesia in infants.…”

Transoesophageal echocardiographic monitoring during paediatric cardiac surgery: obtainable information and feasibility in 532 children

“…This is important information and illustrates the need for dynamic imaging as provided by TOE. Such visual information on heart performance is not accessible to the anaesthesiologist using any other standard monitoring techniques (1).…”

“…Optimal haemodynamic management during paediatric cardiac surgery is a persistent challenge to the anaesthesiologist. This has lead to implementation of several different monitoring techniques in order to improve the circulatory status (1). Unlike in adults, haemodynamic monitoring by means of a pulmonary artery (PA) catheter is not commonly used in children (1) because of the potential risk of complications (2,3).…”

Continuous pH and pCO2 Monitoring Using the Paratrend Inserted Through a Pulmonary Artery or Central Venous Catheter

“…Additional monitoring following cardiovascular surgery may include direct measurements of pulmonary artery pressure and continuous mixed venous oxygen saturation, especially in patients at risk for pulmonary hypertension [10,11]. These devices allow the measurement of mixed venous oxygen saturation as an estimate of cardiac output and pulmonary artery pressure; however, they do not measure pCO 2 or pH.…”