PubMed · 3947179
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J Stark, M R de Leval. 1986. Baffle obstruction.. https://pubmed.ncbi.nlm.nih.gov/3947179/
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Hemodynamics after Norwood palliation for hypoplastic left heart syndrome (HLHS) have been incompletely characterized, although emphasis has been placed on the role that an excess pulmonary-to-systemic blood flow ratio (Qp/Qs) may play in causing hemodynamic instability. Studies suggest that maximal oxygen delivery occurs at a Qp/Qs < 1. However, it remains unclear to what extent cardiac output can increase with increasing pulmonary perfusion. One approach is to use the oxygen excess factor omega, an index of systemic oxygen delivery, and compare omega with measured Qp/Qs. We measured Qp/Qs and omega in neonates after Norwood palliation for HLHS, and determined how they were related. In addition, we determined the temporal course of surrogate indexes of systemic perfusion in the early postoperative period. Arteriovenous oxygen saturation difference, blood lactate, and omega were recorded on admission and every 3 to 12 hours for 2 days in 18 consecutive infants with HLHS or variant after Norwood palliation. Three infants required extracorporeal membrane oxygenation (ECMO) 6 to 9 hours after admission. These infants had higher Qp/Qs, blood lactate, arteriovenous oxygen saturation difference, and lower omega than non-ECMO patients. In non-ECMO patients between admission and 6 hours, omega decreased significantly despite no appreciable change in Qp/Qs. We conclude that: (1) Oxygen delivery is significantly decreased at 6 postoperative hours unrelated to Qp/Qs. This modest decline in oxygen delivery is insufficient to compromise tissue oxygenation. (2) Patients requiring ECMO have significant derangements in oxygen delivery.
BACKGROUND: In the study presented here, an artificial neural network was used to "learn" the relationship between 11 risk factors and patient surgical outcome (survival or death). The network was then used to predict the surgical outcome of other patients. METHODS: Eleven risk factors were presented as inputs to an artificial neural network (ANN). The ANN model was developed by training and testing on 1875 patients. The results of the ANN were compared with the results from two versions of the VA surgical risk model (Denver model). Cutoffs were determined for each model in order to compare their results. RESULTS: The ANN model gave the best results when compared with the new and old Denver models. The ANN model had the lowest overall percentage of error. It predicted living patients with an error of 14% and death with an error of approximately 31.0%. The old Denver model predicted living patients with an error of 15% and deaths with an error of 31%. The new Denver model predicts living patients with an error around 18% and the deaths with an error of 31%. CONCLUSIONS: The combined predictions of the ANN model were slightly more accurate than either the new or the old Denver models. The ANN model was created from 1875 patients in about 1 month, while both of the Denver models were developed over a 3 year time period and used more than 12,000 patients. Additionally, the ANN model is easily modified, allowing instant addition or deletion of parameters to suit the users needs.
Delayed sternal closure is a life saving method in pediatric open heart surgery. We have used a sterile PVC bag sutured to two pieces of chest tubes to close the sternal defect. This is used as a cheaper substitute, which is available in every operating room which can be used as an alternative to PTFE or bovine patch closure.