Neonatal decompensation before surgery in hypoplastic left heart syndrome: a case control study

• Published in: Archives of disease in childhood. Fetal and neonatal edition Vol. 99; no. 6; pp. F468 - F474
• Main Authors: Sheward, Victoria E, Murdoch, Ian A, Durward, Andrew, Tibby, Shane M
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group 01.11.2014; BMJ Publishing Group LTD
• Subjects: Biological and medical sciences; Birth Weight; Blood pressure; Carbon Dioxide - blood; Cardiology. Vascular system; Case-Control Studies; Congenital heart diseases. Malformations of the aorta, pulmonary vessels and vena cava; Delivery. Postpartum. Lactation; Epidemiology; Female; General aspects; Gynecology. Andrology. Obstetrics; Heart; Heart Failure - etiology; Heart Failure - physiopathology; Heart Rate - physiology; Humans; Hypoplastic Left Heart Syndrome - blood; Hypoplastic Left Heart Syndrome - complications; Hypoplastic Left Heart Syndrome - physiopathology; Hypoplastic Left Heart Syndrome - surgery; Infant, Newborn; Intervention; Intubation; Laboratories; Male; Maternal, fetal and perinatal monitoring; Medical sciences; Monitoring, Physiologic - methods; Mortality; Neonates; Norwood Procedures; Oxygen - blood; Oxygen Consumption - physiology; Partial Pressure; Physiology; Prognosis; Public health. Hygiene; Public health. Hygiene-occupational medicine; Pulmonary arteries; Pulmonary Circulation - physiology; Respiratory Rate - physiology; Surgery; Time Factors; Trends; Urine; Variables; Ventilation; Human; Neonatal; Decompensation; Cardiovascular disease; Left Heart Hypoplasia; Case control study; Congenital disease; Epidemiology; Syndrome; Newborn; Treatment; Heart disease; Surgery; Public health; Physiology; Cardiology; Intensive Care; Monitoring
• ISSN: 1359-2998; 1468-2052
• DOI: 10.1136/archdischild-2013-305182

Objective Prior to Norwood 1 surgery, neonates with hypoplastic left heart syndrome (HLHS) are at risk of decompensation from systemic underperfusion secondary to pulmonary overcirculation. We examined whether preoperative temporal profiles of physiological and laboratory variables differed between neonates who did and did not decompensate preoperatively. Design Case control study. Setting Paediatric Intensive Care Unit, 2002–2013. Patients Eighty-five neonates with HLHS, matched by birth weight and admission date. Measurements Decompensation was defined as the need for emergency intubation and ventilation due to clinically diagnosed impaired systemic oxygen delivery. The end point was time of decompensation (cases, n=33) or discharge for surgery (controls, n=52). Variable trajectories were modelled non-linearly using generalised estimating equations. Results Decompensation occurred on median (IQR) day 3 (2–4) of life in cases, with surgery occurring on day 4 (3–7) in controls. Oxygen saturation and blood pressure trajectories were identical between groups (p>0.2). Heart and respiratory rates increased with time overall, but significantly faster in cases than controls; by an average of 4.0 bpm/day versus 1.4 bpm/day (p=0.002) and 5.3 respirations/minute/day versus 1.5 respirations/minute/day, respectively, (p=0.003). Although metabolic blood gas components began to decline subtly 24 h before clinical decompensation, they remained in the normal range for much of this period. Conclusions Heart and respiratory rates, and metabolic acid base trajectories show subtle differences prior to decompensation in neonates with HLHS. These findings highlight the importance of evaluating rates of change rather than absolute values of physiological and laboratory variables.