Cardiac arrest in infants after congenital heart surgery.

BACKGROUND: The survival rate to discharge after a cardiac arrest in a patient in the pediatric intensive care unit is reported to be as low as 7%. The survival rates and markers for survival strictly regarding infants with cardiac arrest after congenital heart surgery are unknown. METHODS AND RESULTS: Infants in our pediatric cardiac intensive care unit database were identified who had a postoperative cardiac arrest between January 1994 and June 1998. Parameters from the perioperative, prearrest, and resuscitation periods were analyzed for these patients. Comparisons were made between survivors and nonsurvivors. Of 575 infants who underwent congenital heart surgery, 34 (6%) sustained a documented cardiac arrest; of these, 14 (41%) survived to discharge. Perioperative parameters, ventricular physiology, and primary rhythm at the time of arrest did not influence outcome. Prearrest blood pressure was lower in nonsurvivors than in survivors (P<0.001). A high level of inotropic support prearrest was associated with death (P=0.06). Survivors had a shorter duration of resuscitation (P<0.001) and higher minimal arterial pH (P<0.02) and received a smaller total dose of medication during the resuscitation. Although survivors had an overall shorter duration of resuscitation, 5 of 22 patients (23%) survived to discharge despite resuscitation of >30 minutes. CONCLUSIONS: The outcome of cardiac arrest in infants after congenital heart surgery was better than that for pediatric intensive care unit populations as a whole. Univentricular physiology did not increase the risk of death after cardiac arrest. Infants with more hemodynamic compromise before the arrest as demonstrated with lower mean arterial blood pressure and higher inotropic support were less likely to survive. The use of predetermined resuscitation end points in this subpopulation may not be justified.

Oxygen transport in critically ill infants after congenital heart operations.

BACKGROUND: Oxygen transport variables reflect the balance of oxygen delivery and demand. Because oxygen transport in infants undergoing congenital cardiac operations is not well described, we examined oxygen transport in such patients. Differences in oxygen transport between survivors and nonsurvivors and variables that might be predictive of outcome were sought. METHODS: We reviewed hospital records of infants admitted to the pediatric cardiac intensive care unit in our institution from January 1996 through April 1997. Infants in whom simultaneous arterial blood gas and systemic venous oxygen saturation measurements were performed on admission and at 6 and 24 hours after admission were included. Analyses of arterial pH, base excess, arteriovenous oxygen saturation differences, and oxygen extraction ratio were performed, including comparisons of survivors and nonsurvivors and changes over time. RESULTS: Forty-nine infants were included in the study, with 39 survivors. There were no differences in any parameter between survivors and nonsurvivors on admission or at 24 hours. At 6 hours, differences between survivors and nonsurvivors were significant for arterial pH (7.48 versus 7.35, p<0.001), base excess (2.9 versus -4.3 mmol/L, p<0.01), arteriovenous oxygen saturation difference (34 versus 43, p<0.05), and oxygen extraction ratio (0.28 versus 0.53, p<0.001). The oxygen extraction ratio at 6 hours was at least 0.5 in 6 of 39 survivors and 7 of 10 nonsurvivors (p = 0.002). CONCLUSIONS: Infants who die after cardiac operations have significant derangements of oxygen transport at 6 hours after admission to the intensive care unit. Infants with an oxygen extraction ratio greater than 0.5 at 6 hours are at highest risk.

The outcome of cardiac operations in infants weighing two kilograms or less.

OBJECTIVE: A review of our recent experience of operating on infants weighing 2 kg or less who had congenital heart disease was performed to determine the outcome of early surgical repair or palliation. METHODS: A retrospective review of hospital records was performed for infants who weighed 2 kg or less and who were identified to have undergone cardiac operation at our institution January 1992 to June 1997. The data collected included age, weight, gestational age, cardiac diagnosis, surgical procedure, and outcome measures such as length of stay, morbidity, and mortality rate. Outpatient charts were reviewed for follow-up survival and cardiac status. RESULTS: Thirty-three operations were performed on 30 patients. Median age at operation was 19.5 days (1 to 140 days), and median weight was 1.8 kg (1.1 to 2.0 kg). Cardiac diagnoses varied, with coarctation of the aorta and tetralogy of Fallot most common. Twenty-four patients were born at 37 or fewer weeks' gestation. Hospital survival was 83% with no difference in mortality rates based on age, weight, or type of surgical procedure. Premature infants tended to have worse hospital survival. Median postoperative length of stay was 39 days (6 to 122 days). Median duration of mechanical ventilation in survivors was 6 days (2 to 24 days). Neurologic complications were documented in eight patients. Of the 25 hospital survivors, 20 (80%) are alive with good cardiac status at a mean follow-up of 13 months. CONCLUSION: Cardiac operations in a selected group of infants weighing 2 kg or less can provide acceptable hospital survival. In most instances, complete repair is possible with good medium-term outcome in the survivors. Investigation into neurologic outcomes in these patients is warranted.

Use of single lead VDD pacing in children.

The development of transvenous ventricular pacing leads with proximal electrodes capable of atrial sensing and the recent availability of smaller generators has created the opportunity to treat children with complete AV block and normal sinus node function with a transvenous single lead VDD pacing system. Studies in adults have demonstrated this system to be efficacious with low complication rates. Transvenous single lead VDD pacemakers were implanted in ten children, aged 5-15 years, between December 1993 and April 1996, in our institution. The indications were complete AV block with severe bradycardia in 5 patients, second-degree or complete AV block following congenital heart surgery in 3, complete AV block with long QT syndrome in 1, and second-degree AV block and syncope in 1. There were no complications related to the procedure in any case. P and R wave amplitudes were measured and thresholds were determined intraoperatively on all patients. Amplitudes and thresholds were remeasured on seven patients with a mean follow-up of 17 months; Holter monitors were performed on seven patients with mean follow-up of 16 months. P and R wave amplitudes were generally diminished at follow-up compared to initial values but remained within an acceptable range for all patients. Four patients required reprogramming after pacemaker insertion, 1 received an atrial lead for dual chamber pacing, 1 required reposition for lead dislodgment, and 1 patient required a new lead for an inadequate ventricular pacing threshold. No patient had evidence of failure to sense or capture as evaluated by Holter monitoring at last follow-up. Single lead VDD pacing systems can be successfully used in properly selected children with high degree or complete AV block with normal sinus node function.

Alzheimer's disease: a current review.

Alzheimer's disease is characterized by a progressive decline in cognitive function from a previously established level, and is the most common cause of all the dementias. While the exact etiology remains to be determined, there are several theories about possible genetic, immunological, biochemical and viral causes. Clinical diagnosis is by exclusion of other established causes of dementia and requires a careful history, physical examination and, often, psychological testing. Definitive diagnosis is made at post-mortem, although some cases show none of the histological hallmarks such as neurofibrillary tangles or senile plaques. There is no effective preventive or therapeutic treatment. Symptomatic management includes pharmacotherapy, socialization, support for the patient and his family and, ultimately, institutionalization. Patients are best managed by an interdisciplinary team using community resources.