Infant apnea detection after herniorrhaphy

STUDY OBJECTIVE

To elucidate risk factors for apnea in preterm infants discharged from the hospital and in full-term healthy infants. To determine the efficacy of real-time cardiopulmonary monitoring versus computerized storage and retrieval for infants at risk.

STUDY DESIGN

Prospective study.

SETTING

Operating rooms and pediatric patient care units of university medical center.

PATIENTS

27 preterm infants and 20 full-term infants no more than 60 weeks' post-conceptional age, who were admitted for elective herniorrhaphy.

INTERVENTIONS

Infants were monitored before and after herniorrhaphy with general anesthesia using an infant apnea impedance monitor, pulse oximetry, and nursing observation.

MEASUREMENTS AND MAIN RESULTS

Demographic information and medical history were correlated with postoperative apnea. The sensitivity and specificity of nursing observation and oximetry were compared with computerized apnea monitors. Five patients (11%, four preterm, one full-term) were apneic postoperatively as recorded by computerized pneumocardiography. Previous apnea history, gestational age at birth, and postconceptional age at operation positively correlated with postoperative apnea. Nursing observation failed to detect 4 of 5 patients with documented apnea (sensitivity 20%, positive predictive value 50%). Pulse oximetry failed to detect 3 of 5 patients with apnea (sensitivity 40%, positive predictive value 66%).

CONCLUSIONS

Although it is easier to predict postoperative respiratory dysfunction in previously sick or very young infants, absolute predictability for all neonates remains elusive. Clinical monitors with both storage and retrieval capabilities and real-time monitoring increase our ability to detect significant events in children at risk for apnea after herniorrhaphy.

The effect of intravenous dextrose infusion on postbypass hyperglycemia in pediatric patients undergoing cardiac operations

STUDY OBJECTIVE

To determine whether elimination of intraoperative dextrose-containing infusions affects post-cardiopulmonary bypass hyperglycemia in pediatric patients.

DESIGN

Randomized, unblinded, saline-controlled study of perioperative glucose infusions in children undergoing cardiac surgery.

SETTING

Cardiac surgery suite and pediatric intensive care unit (ICU) of a university medical center.

PATIENTS

33 consecutive, nondiabetic children undergoing cardiac surgery with deep hypothermia over an 8-month period.

INTERVENTIONS

Group A (n = 16) received only normal saline infusions intraoperatively, and Group B (n = 17) received 5% dextrose and lactated Ringer's solution exclusively. Blood glucose was sampled immediately after induction of anesthesia, prior to cardiopulmonary bypass (CPB), after separation from CPB, on arrival in the ICU, and the morning of the first postoperative day. Data were analyzed using Student's t-test for independent samples, paired t-test, and analysis of variance, with p < 0.05 considered significant.

MEASUREMENTS AND MAIN RESULTS

Although moderate elevations in blood glucose (mean less than 165 mg/dl) after CPB were present in Group A, significantly higher levels (mean greater than 250 mg/dl) were noted in Group B. No children were hypoglycemic (glucose less than 40 mg/dl). Glucose levels were normal in both groups on the morning of the first postoperative day despite patients' having received continuous dextrose infusions in the ICU and the presumed stress of emergence from anesthesia.

CONCLUSIONS

Extreme postbypass hyperglycemia can be controlled by eliminating intraoperative dextrose infusions. Hypoglycemia, an unlikely event, can easily be avoided by regular blood sampling, which is facilitated by the routine placement of arterial catheters.

Predictors of postoperative respiratory complications in premature infants after inguinal herniorrhaphy

There is a significant incidence of inguinal hernia in premature infants and the optimal timing of repair is controversial. A high rate of postoperative respiratory complications has been reported in this group. In this study, the records of 47 premature infants (mean gestational age, 30.3 weeks) who underwent herniorrhaphy while still in the neonatal intensive care unit were reviewed in an effort to define those conditions that are independent risk factors for complications. Forty-three percent of infants had complications, including postoperative assisted ventilation (34%), episodes of apnea and/or bradycardia (23%), emesis and cyanosis with first feeding (6%), and requirement for postoperative reintubation (4%). Although low gestational age and postconceptual age at operation, low birth weight for gestational age, and preoperative ventilatory assistance were significantly associated with postoperative complications, only a history of respiratory distress syndrome/bronchopulmonary dysplasia (odds ratio 2.3), a history of patent ductus arteriosus (odds ratio 2.5), and low absolute weight at operation (odds ratio 3.5 for 1,000-g decrease) were independent risk factors for postoperative complication. Despite previous reports citing postconceptual age as the factor having the greatest impact on postoperative complications, these results indicate that a history of respiratory dysfunction and size at operation may be more important predictors of postoperative respiratory dysfunction in preterm infants.

Role of the thalamus in language: is it related to schizophrenic thought disorder?

Crosson (1985) proposed a model for language production which integrated cortical with subcortical functions. The implications of this model for schizophrenia are explored. One conclusion is that neural systems, as opposed to a single neural focus, account for schizophrenic symptoms. In this light, data regarding dysfunction in the limbic system, nucleus accumbens, globus pallidus, and prefrontal cortex, which are often seen as contradictory, can be viewed as complementary. Another conclusion is that Crosson's model may have implications specific to schizophrenic thought disorder. Random triggering of semantic segments and inability to maintain contextual referents are discussed in the context of the language production theory.

Cerebral blood flow and cerebrovascular permeability in an inescapable shock (learned helplessness) animal model of depression

The effects of a purported animal model of depression (inescapable shock, IS) was tested on: (a) escape behavior, (b) regional brain levels of norepinephrine (NE), serotonin (5-HT), and dopamine, and (c), the response of the cerebromicrovasculature to metabolic demand as mimicked by manipulation of arterial CO2 content (PaCO2). Multidisciplinary research has implicated central biogenic amines in the regulation of cerebromicrocirculation. IS treatment resulted in increased escape latency and lowered levels of NE and 5-HT in the locus coeruleus but not in terminal fields in distant regions. This treatment also did not alter cerebral blood flow or capillary permeability in distant regions when compared with control rats. Thus, the discrete changes in NE and 5-HT in locus coeruleus induced by IS treatment is not reflected in changes in cerebral blood flow and the effective permeability of the blood-brain barrier.

Ethanol effects on brain concentrations of amitriptyline and the relationship to psychomotor function

The effect of amitriptyline (AMI), ethanol (ETOH), and ETOH followed by AMI on both general activity (open field) and motor performance (two rotorod tasks) was tested in reference to a saline-injected control. The combination (ETOH plus AMI) produced greater impairment on all three tasks than did either drug alone. ETOH pretreatment also produced a 223% increase in the total tricyclic antidepressant (TCA) brain concentration. The decrement in motor performance was logarithmically related to total TCA brain concentrations in both animals treated with AMI alone and those pretreated with ETOH prior to AMI. The concentration which consistently produced behavioral impairment was similar to those previously reported to cause cognitive and electroencephalographic dysfunction in humans.

Role of the central adrenergic system in mediating amitriptyline-induced alteration in the mammalian blood-brain barrier in vivo

All tricyclic antidepressants increase the degree of equilibration of [3H]water across the cerebral capillary (Ew) as measured by a dual-label radioactive tracer technique. By using amitriptyline (AMI) as a prototype, a series of studies was conducted to determine the mechanism for this drug effect. The AMI-induced increase in Ew was blocked by 6-hydroxydopamine ablation of central aminergic neurons and by pretreatment with phenoxybenzamine, an alpha adrenergic antagonist. Pretreatment with propranolol, a beta adrenergic antagonist, did not block the AMI-induced increase. Central serotonergic ablation by p-chloroamphetamine had no effect on the AMI-induced increase. Treatment with atropine and hydroxyzine separately also did not alter Ew. Based on these results, the AMI-induced increase in Ew appears to be mediated by the effect of the drug on central adrenergic neurons. The serotonergic, anticholinergic and antihistaminergic actions of AMI, by themselves, do not appear to play a role in this phenomenon. The results are compatible with the concept that the central adrenergic system functions, in part, to regulate the cerebromicrocirculation.

Outcome of early experience studies as affected by between-litter variance

Studies of early experiences in animals in which the mother or the entire litter is manipulated often involve significant levels of between-litter variance. Such variance, if not accounted for either by analysis which considers litter as an independent source of variance, or by use of mean litter scores, may contribute to misleading treatment effects. This phenomenon is demonstrated for experiments utilizing analysis of variance procedures for data analysis.

Maternal behavior of wild and domestic Rattus norvegicus recorded continuously in dual-chambered cages

Continuous measurements of maternal behavior--the amount of time the mother was in contact with the litter and quality of nest--indicated no differences between these 2 stocks of rats. A decrease in both measures was found for both stocks over the 22 days of postnatal observation. The data indicated that the mother was with the litter more during the light portion of the 24-hr light-dark cycle and that wild rat mothers were in contact with their litters more than domestic mothers in the period around light offset.

Early experience in domestication

Two experiments using domestic and wild rats (Rattus norvegicus) were conducted to assess the ontogenetic as well as phylogenetic influences of early experience on domestication. Experiment 1 was a factorial, reciprocal cross-foster study. Experiment 2 was a factorial assessment of the combined effects of preweaning handling and postweaning enriched environments. These experiments on rat domesticatoin showed that preweaning handling has a strong influence on the ontogenetic development of the rat in terms of reduced emotionality. Handled wild rats became much more like domestic rats in their behavior. This finding for handling contrasted with minimal effects for cross fostering and enriched environments.

A review of the late General Eisenhower's operations: epilog to a footnote to history

Images