Optimising Haemodynamics in the Shocked Child: The Dangers of Applying Adult Parameters to Children

The data can then be used to institute early goal directed therapy and for regularmonitoring to ensure that haemodynamics are optimised.We studied 100 children from 1 to 16 years of age using the USCOM to evaluate normal haemodynamics.We found that there were major differences between the typical values found in children and those inadults. The cardiac index for example in our subjects was typically 4.2 ' 4.4 L/min/m2 or almost doublethat quoted for adults. Similar disparities were identified for CO, S, SVR and DO2. The often-quoted useof pulse pressure as an indicator of SV and CO was shown to be unsupportable in our subjects, with nostatistical correlation between pulse pressure and these haemodynamic parameters. We suggest that in thecase of the shocked child, extrapolation for haemodynamic values derived from adult investigations arelargely inappropriate and potentially dangerous, with serious risk of inadequate treatment of the child.Suggested goals for optimizing haemodynamics in children will be presented and contrasted with values that optimise output.The shocked child is a highly demanding paediatric emergency. The adoption of early goal directedtherapy (EGDT) in resuscitation to improve the haemodynamic status of the patient has resulted in adramatic reduction in morbidity and mortality in both adults and children, particularly in the areas of theseptic shock syndrome. The most important physiological variables to assess in the critically ill patient,apart from heart rate and blood pressure, are the cardiac output (CO), cardiac index (CI), stroke volume(SV), systemic vascular resistance (SVR) and oxygen delivery (DO2). Measurement of these parameters,even in adults, has always involved a high degree of invasiveness, as in the pulmonary artery catheter, orrelatively poor accuracy with low invasive devices such as the transoesophageal Doppler. The significantdangers and difficulties of using such invasive monitoring have largely precluded their use in the sickchild. In addition, there is very little published data regarding typical values of these parameters innormal children, due to the highly invasive nature of the investigations required and the inevitabledistortion of the data that results from the pain and anxiety of performing the measurements. Inconsequence, many of the therapeutic goals used in the shocked child are extrapolations from adultobservations and treatment protocols. The advent of the highly accurate yet entirely non-invasiveultrasonic cardiac output monitor (USCOM) permits the rapid (less than 5 minutes) determination of CO,CI, SV, SVR and DO2.