Haemodynamic effects of atropine during halothane or isoflurane anaesthesia in infants and small children

Abstract

In this study, two-dimensional and pulsed Doppler echocardiography were used to measure cardiovascular changes before and after IV atropine in 31 infants and small children during halothane (n = 15) In children (mean age 6 yrs) IV atropine administered during halothane and nitrous oxide anaesthesia increased cardiac output (CO). t In previous studies of infants who received PO or IM atropine premedieation, heart rate (HR) and mean blood pressure (MBP) have been reported to be greater than during halothane and nitrous oxide anaesthesia alone. 2,3 This suggests that atropine may attenuate the cardiovascular depression produced by halothane and nitrous oxide anaesthesia.2,3 Whether these haemodynamic changes following atropine are solely the result of an increase in HR or are the result of changes in other myocardial determinants, as well as increases in HR, is unclear.t'3Halothane and isoflurane produce dose-related direct myocardial depression that appears to be more profound in the young compared with the adult animal .4,5 In an in vitro study using feline papillary muscle, the degree of myocardial depression produced by halothane and isoflurane appear similar, if compared at equianaesthetic levels. 6 In a previous clinical study of infants and small children that compared equianaesthetic concentrations of halothane and isoflurane, the haemodynamie differences between halothane and isoflurane in infants and children were mainly the result of differing effects on HR, as decreases in ejection fraction (EF), stroke volume index (SVI) and cardiac index (CI) were of similar CAN J ANAESTH 1989 / 36'. 3 / pp295-300

Comparative Hemodynamic Depression of Halothane Versus Isoflurane in Neonates and Infants

“…Similar to prior studies in infants and small children, the increased heart rate after atropine increased cardiac output but did not attenuate myocardial depression as measured by ejection fraction and stroke volume in either neonates or infants (30). The increased heart rate did not compensate for decreased stroke volume, and cardiac output remained depressed from awake levels in both neonates and infants.…”

Immediate and 5‐year cumulative outcome after paediatric intensive care in Sweden

“…Anaesthesia influences CO in more than one way; preload, afterload and contractility are all affected as well as heart rate, whereas changes in mean airway pressure are considered to have a more selective effect on preload. Murray et al 212 showed an increase in heart rate and cardiac output but not stroke volume of atropine. Their study also showed that the anaesthesia with halothane and isoflurane, before atropine was given, gave a decrease in both CO and stroke volume compared to preanaesthesia values.…”

Magnetic Resonance Imaging (MRI) reveals high cardiac ejection fractions in red-footed tortoises (Chelonoidis carbonarius)

“…The failure of atropine to increase f H was unexpected, particularly given the marked effects on the pulmonary circulation that also obey an inhibitory vagal influence (Burggren, 1975), and may be attributed to the isoflurane anaesthesia. It is possible that the direct cardio-depressive effect of isoflurane may have lowered the EF (Housmans et al, 2000;Murray et al, 1989). Alternatively, or in addition, isoflurane may have reduced the afterload (through arterial hypotension), which could increase EF compared with that in conscious tortoises, given the steep negative relationship between V s and afterload in chelonians (Farrell et al, 1994;Joyce et al, 2016).…”