The influence of different strategies on clinical outcome in patients undergoing total cavopulmonary connection

Mechanical ventilation strategy following Glenn and Fontan surgeries: On going challenge!

The Glenn and Fontan operations put the pulmonary and systemic circulations in series. It has been shown that positive pressure ventilation (PPV) decreases pulmonary blood flow (PBF) and cardiac output (CO), and negative pressure ventilation (NPV) significantly improves PBF and CO. If early extubation is not achievable, the postoperative ventilator management strategy should aim at promoting PBF and CO by lowering pulmonary vascular resistance (PVR) and intrathoracic pressure. Multiple ventilator strategies have been evaluated to optimize this physiology, including high frequency ventilation, hyperventilation post Glenn, hypoventilation post Glenn with buffered pH, and the use of inhaled nitric oxide as an adjunct therapy for mechanical ventilation. In this review, the results of these studies will be reviewed and discussed.

The impact of altitude on early outcome following the Fontan operation

BACKGROUND

The success of a Fontan circulation depends on several factors including low pulmonary vascular resistance. Pulmonary vascular resistance rises in response to hypoxia. Hypoxia is associated with altitude. Therefore, we wondered whether altitude is a risk factor for early failure after the Fontan operation. The aim was to test this hypothesis.

METHODS

Data were obtained from all published series of 'total cavopulmonary' Fontan operations since 1990. The early failure rate from each series and the altitude of the respective cities were recorded. Early failure was defined as death, takedown of Fontan, or transplantation during the same hospital admission. The association between altitude and failure rate was investigated by rank correlation and logistic regression.

RESULTS

24 series were identified from centres situated at altitudes ranging from sea level to 520 metres. The plot of failure rate versus altitude suggests that failure rate increases with altitude. Logistic regression did not fit the data adequately. This was possibly due to the influence of unmeasured and unknown factors affecting the results, as well as the fact that centres were not randomly chosen but were self-selected by virtue of publishing their results. However, Spearman's rank correlation was 0.74 (p = 0.001).

CONCLUSION

The early outcome of the Fontan circulation appears to be adversely affected by altitude.

Essentials of Nitric Oxide for the Pediatric (Cardiac) Anesthesiologist

Short- and long-term survival rates for the operative treat ment of congenital heart disease (CHD) have improved significantly in the past 2 decades. The increasing sophisti cation of the pediatric cardiologist's diagnostic armamen tarium has led to more pervasive use of fetal screening with echocardiography. Early diagnosis and pre-emptive care of the neonate with complex CHD have allowed interventional strategies in the catheterization suite or the operating room to be optimized in both the timing and the quality of pallia tive or corrective procedures. Medications such as prosta glandin E and ventilator strategies using hypoxic and hyper carbic inspired gases exemplify therapies benefitting the contemporary neonate with CHD, often allowing stabiliza tion of the patient before surgery. Surgical care of neonates, infants, and children with CHD has also improved. Insights into maturational differences in myocardial and autonomic function have led to more appropriate myocardial protection strategies and pharmacologic support of the circulation. Recognition of those anomalies in which total correction in the neonate is desirable has stimulated improvements in the technical and cognitive skills of pediatric cardiovascular sur geons and pediatric cardiac anesthesiologists to meet these challenges. The goal of this article is to provide the pediatric anesthesiologist with an overview of inhaled nitric oxide and its relevance to clinical practice.