Pediatric organ donor maintenance: pathophysiologic derangements and nursing requirements.

A retrospective chart review was conducted of 26 organ donors to determine hemodynamic and metabolic derangements encountered and nursing requirements for donor organ maintenance. There were 15 boys and 11 girls with a mean age 6.57 +/- 5.46 years. Mean donor maintenance time was 10.5 +/- 6.7 hours. Cardiorespiratory derangements included hypotension in 16, hypertension in 6, arrhythmias in 17 (premature ventricular contraction in 4, bradycardia in 8, paroxysmal atrial tachycardia in 3, and ventricular tachycardia in 2), asystolic events in 5, pulmonary insufficiency in 6, anemia in 8, and thrombocytopenia in 8. Metabolic and hormonal derangements included hyperglycemia in 18, hypokalemia in 20, hyperkalemia in 4, hyponatremia in 3, hypernatremia in 17, metabolic acidosis in 10, and diabetes insipidus in 15. Hypothermia (temperature 33.3 degrees +/- 0.4 degrees C, mean +/- SD) occurred in 14 donors. The mean physiologic Stability Index score was 22.2 +/- 4.7 and mean Therapeutic Intervention Score was 46.7 +/- 5.8. Total number of nursing hours spent in donor maintenance was 424.5 hours. Therapies offered included diuretics in 10, sodium bicarbonate in 8, antibiotics in 6, insulin in 12, pitressin in 13, verapamil in 3, isoproterenol in 3, dopamine in 17, and intravenous potassium boluses in 14. Of the potential 26 donors, 46 kidneys, 8 hearts, 14 livers, 3 pancreas, and 9 corneas were retrieved in transplantable condition. With appropriate donor maintenance, organs suitable for transplantation can be retrieved despite significant pathophysiologic derangements. Physicians intending to provide donor support should be comfortable with invasive monitoring and cardiorespiratory support and be prepared to provide a nurse to patient ratio of 2:1 at the bedside.

Resistance of the auditory brain stem response to high barbiturate levels.

In the comatose patient the auditory brain stem response may be one of the few indices of CNS function available. Because barbiturates may be administered to control intracranial pressure and its sequelae, demonstration of the effect of barbiturates on the brain stem response is desirable. In cats preloaded with 63 mg/kg of pentobarbital, intravenous injection of an additional 60 mg/kg reduced, but did not abolish, the later waves of the response. One cat that survived a cumulative dose of 183 mg/kg continued to show a well-defined brain stem response. Even doses of barbiturate nearly incompatible with survival do not abolish this response.

Adult respiratory distress syndrome in a child with acute epiglottitis.

Intubation of a 23-month-old child suffering epiglottitis was complicated by pulmonary edema progressing to the adult respiratory distress syndrome. Increased pulmonary shunt and pulmonary hypertension required high levels of positive end-expiratory pressure and prolonged mechanical ventilation to correct hypoxemia. A possible role for a cuffed endotracheal tube in epiglottitis is discussed.

Guidelines for stabilizing the condition of the critically ill child before transfer to a tertiary care facility.

The initial resuscitation and stabilization provided to a critically ill or injured child is often an important determinant of outcome. Before transfer to a tertiary care facility the initial care may be provided by physicians unaccustomed to managing critically ill children. The authors outline the unique aspects of resuscitation and stabilization of the critically ill child and give guidelines for the initial management of diseases affecting the central nervous system and respiratory tract (the most frequent indications for transfer to a tertiary care facility) and other, less frequent but important problems. In many situations it is worth while to enlist the expertise of the tertiary care centre, either by telephone consultation or by dispatch of a specially trained transport team.

An evaluation of the physical and functional characteristics of resuscitators for use in pediatrics.

OBJECTIVE: To evaluate the physical and functional characteristics of pediatric self-inflating resuscitators. DESIGN: Tested under simulated clinical conditions. Results were analyzed by descriptive analysis. SETTING: A pulmonary laboratory in a university hospital. METHODS: Eight new pediatric self-inflating resuscitators were obtained from the manufacturers and evaluated for functional characteristics including: a) fraction of delivered oxygen at 10 L/min and a tidal volume of 300 mL; b) maximum stroke volume against no resistance; and c) maximum cycling frequency at -5 degrees C, 20 degrees C, and 48 degrees C. The resuscitators were also evaluated for physical characteristics, including potential for misassembly, pressure relief valves, expiratory valve leak, and inspiratory resistance. RESULTS: All resuscitators met the minimum standards of the Canadian Standards Association and American Standards for Testing of Materials. However, one bag cycled at only 32 breaths/min at -5 degrees C, marginally within accepted standards. Only five self-inflating resuscitators had pop-off valves. These valves malfunctioned, with valve activation occurring well above the accepted standards. Three of the self-inflating resuscitators could be misassembled for use. Four of the resuscitators were unable to deliver tidal volumes required for preoxygenation in a 20-kg child. CONCLUSIONS: While these self-inflating resuscitators met the minimum standards, they are all unable to deliver 100% oxygen. One unit is probably not appropriate in the out-of-hospital setting when ambient temperatures are less than 0 degrees C. Those resuscitators that can be misassembled are dangerous in unskilled hands. In addition, reliance on pop-off valve activation to limit airway pressure is dangerous.

The effect of physician education on knowledge of drug therapeutics and costs.

OBJECTIVE: To determine if a clinical pharmacist-sponsored education program regarding physician knowledge of drug costs and therapeutics would change drug utilization and costs for specific high-cost groups of drugs in a pediatric critical care unit (PCCU). STUDY DESIGN: Prescribers within the PCCU completed a questionnaire addressing drug costs and therapeutic issues. Subsequent to the questionnaire the PCCU liaison pharmacist implemented a visual display of monthly drug costs, an education program that included the presentation of questionnaire results, and drug information lectures discussing controversial therapeutic issues. After the education program participants again completed the questionnaire. SETTING/PARTICIPANTS: The study was conducted in a 13-bed PCCU in a regional children's hospital. The participants were postgraduate trainees in pediatrics and critical care medicine as well as attending staff in the PCCU. OUTCOME MEASURES: The main outcome measure was the score on a test addressing drug costs and therapeutic issues. RESULTS: The mean overall posteducation score (52.5 percent) improved significantly from the preeducation score (46.4 percent). The preeducation questionnaire results indicated increased knowledge of costs by residents and increased knowledge of therapeutics by attending physicians. The number of educational sessions attended appeared to be associated with improvement in overall questionnaire scores. CONCLUSIONS: There was improvement in knowledge of drug costs and therapeutics associated with the educational program. Although this relationship did not reach statistical significance, this may be related to the relatively small sample size of our study. Our results suggest that clinical pharmacists can positively influence physicians' knowledge on drug costs and therapeutics.

Assessment of pediatric near-drowning victims: is there a role for cranial CT?

Previous studies have suggested that CT examinations of the brain in children soon after near-drowning incidents are not helpful in predicting clinical outcome and are not necessary. The clinical and CT findings of 19 pediatric near-drowning victims were reviewed for correlation with clinical and neurologic outcome. As expected, a normal initial CT scan was poorly predictive of outcome, whereas an abnormal CT scan in the initial 36 h following an immersion incident was associated with a dismal prognosis. Three children with abnormal initial CT examinations were identified and all died within 3 days of admission. A CT scan performed in the immediate near-drowning period, therefore, may be helpful in identifying some patients who have sustained severe neurologic injury.

An evaluation of the physical and functional characteristics of infant resuscitators.

Self-inflating resuscitators (SIRs) are commonly used to assist ventilation in the newborn. Despite their widespread use, there is limited information available on the functional and physical characteristics of SIRs. We studied five new infant bag-valve units to compare their physical characteristics, including reservoir, accumulator, and dead space volumes (VD), pressure relief mechanism (PRM), inspiratory resistance (RI), and functional mechanics including stroke volume (SV), fraction of delivered oxygen (FDO2), and cycle frequency at -5 degrees C, 20 degrees C, and 49 degrees C, using a test lung apparatus and experienced respiratory therapists. In addition, deficiencies and features that may render them less than ideal were sought. All SIRs met minimum standards for reservoir and accumulator volumes, RI (< 20 cmH2O/L/sec), SV (20-70 ml), and FDO2 (> 90%) as determined by the Canadian Standards Association (CSA) and the American Society for Testing of Materials (ASTM). However, the following deficiencies were noted: 1) MPR and Pulmanex had no PRM (ASTM requirement); 2) MPR could not cycle at -5 degrees C; 3) the VDs for Pulmanex (10 ml) and MPR (15 ml) were high; 4) the CPR connector broke during normal use, and the MPR connector frequently disconnected; 5) the Laerdal expiratory valve was incompetent; and 6) the Laerdal and CPR could be misassembled for use. Our study shows that some commercially available SIRs do not meet all CSA and ASTM standards and may not be ideal in specific clinical situations. The choice of a SIR may be dictated by the clinical situation in which its use is intended.

Cerebral blood flow, metabolic rate, and cross-brain oxygen consumption in brain injury.

In six deeply comatose children, the relationships of intracranial pressure, cerebral perfusion pressure, cerebral blood flow, cross-brain oxygen consumption, and metabolic rate to outcome were studied sequentially during therapy. Intracranial pressure, cross-brain oxygen consumption, and metabolic rate values were significantly different in the three children who survived compared with those in the three who died. The differences in cross-brain oxygen consumption and metabolic rate occurred in the presence of clinically acceptable values for intracranial and cerebral perfusion pressures. Cross-brain oxygen consumption and metabolic rate may be important indicators of degree of neuronal injury, and of outcome.

The child requiring transport: lessons and implications for the pediatric emergency physician.

A retrospective review of the charts of all patients transported by our emergency transport team was done to determine the following characteristics: age, presenting problem, and outcome of patients and utilization of transport team personnel. Eighty-five percent of patients were under six years of age; central nervous system pathology accounted for 53% of patients transported, followed by respiratory problems (30%), cardiac problems (4.2%), and major trauma (2.7%). Sixty patients survived with normal neurologic examination at discharge. A statistically significant difference in retrospectively assigned PSI score (17.0 +/- 6.02 in nonsurvivors versus 5.8 +/- 6.02 in survivors) was observed. Utilization of the transport team was deemed appropriate. Comparison of our data with other available sources, as well as suggestions for emergency physicians and continuing medical education programs, is outlined.

Effects of hyperventilation, hypothermia, and altered blood viscosity on cerebral blood flow, cross-brain oxygen extraction, and cerebral metabolic rate for oxygen in cats.

Therapies including hyperventilation (HV) and hypothermia (HT) are currently simultaneously used in brain-injured children at risk for cerebral swelling to reduce cerebral blood flow (CBF) and alter cerebral metabolic rate for oxygen (CMRO2). Since HV and HT may contribute to significant patient morbidity, we evaluated the effects of these treatments in combination on CBF, CMRO2, and cross-brain oxygen extraction (CBO2) using the Kety-Schmidt technique before controlled bleeding to alter blood viscosity in 20 lightly anesthetized, paralyzed cats, and after bleeding in another 17 cats. The degree of HV (PaCO2 24 to 26 torr) and HT (32 degrees and 30 degrees C) used were representative of that employed in pediatric neurointensive care. HV at normothermia resulted in a significant decline in CBF (P less than .05) and an unchanged CMRO2. HV and HT together to 32 degrees C resulted in a further significant fall in CBF and CMRO2 (p less than .05), but an unchanged CBO2. Further cooling of the animal to 30 degrees C during HV, both before and after controlled bleeding, resulted in no further significant fall in CBF, CBO2, or CMRO2. This relationship was found despite a significant fall in Hgb (p less than .001), suggesting that blood viscosity did not significantly influence CBF at this temperature. Our data suggest that HT to 32 degrees C during HV may have therapeutic benefit by decreasing CBF and CMRO2, but further cooling to 30 degrees C may not result in further cerebral protective effects.

Prototype volume-controlled neonatal/infant resuscitator.

Face mask or bag endotracheal tube manual ventilation of neonates and infants has relied primarily on the use of self-inflating resuscitation devices (SIRs). While SIRs have the advantage of being simple to use and, therefore, require minimal training, recent research has demonstrated significant drawbacks to these devices. These drawbacks have included their large physical size, the tendency of such devices to cause significant hyperventilation, and the extreme variability of pressures necessary to activate the pop-off valve safety feature. This latter problem is especially serious in the infant where large pressure variations may increase the potential for pulmonary barotrauma. In an attempt to minimize the disadvantages of SIRs, we developed a prototype volume-controlled resuscitation device (VCD). We then compared the VCD to the SIRs in a cat model using blinded volunteer health care personnel previously familiar with SIRs only. Ventilation of the cat with the VCD yielded arterial and end-tidal CO2 values more closely resembling the physiologic state at a lower mean airway pressure. The data suggest that a human trial of manual ventilation with the prototype VCD is warranted.

The effect of cephalothin prophylaxis on postoperative ventriculoperitoneal shunt infections.

Postoperative infection is an important complication after insertion of a ventriculoperitoneal (VP) shunt in children with hydrocephalus. A randomized double-blind placebo-controlled study was performed to determine the efficacy of cephalothin in preventing postoperative shunt infection. Sixty-three children who presented for elective VP shunt insertion between January 1982 and December 1985 and who did not have a history of shunt infections were randomly assigned to receive four doses of prophylactic cephalothin, 25 mg/kg (32 patients), or of a multivitamin placebo (31 patients). Postoperative infection developed in 6% of the treatment group, compared with 10% of the placebo group, a difference that was not statistically significant, although a clinical significance may have been masked by the small sample size. A large multicentre trial is needed to determine the efficacy of antibiotic prophylaxis in reducing the incidence of postoperative VP shunt infections.

Bilateral lower extremity compartment syndromes secondary to intraosseous fluid resuscitation.

Intraosseous infusions are reserved for use in life-threatening hypovolemic or cardiogenic shock when intravenous (i.v.) access cannot be readily established. Although minor fluid extravasation is a common problem with this technique, a fully established compartment syndrome has never been reported. We describe a child with severe compartment syndromes of both lower extremities complicating the use of intraosseous fluid resuscitation.

Cerebral blood flow, cross-brain oxygen extraction, and fontanelle pressure after hypoxic-ischemic injury in newborn infants.

The relationship between mean arterial pressure, intracranial pressure, cerebral blood flow, cross-brain oxygen extraction, cerebral metabolic rate, and outcome was studied during therapy in nine neonates on 3 consecutive days after severe hypoxic-ischemic cerebral injury. Cross-brain oxygen extraction was significantly higher (5.06 +/- 0.5 vs 2.05 +/- 0.8 ml/dl; p = 0.012) in the five neonates who survived with normal neurologic outcome than in the four who died or sustained severe brain damage. In contrast, global cerebral blood flow in the five neonates with normal neurologic outcome was significantly lower (25.6 +/- 8.2 vs 83.2 +/- 44.9 ml/100 gm brain/min; p less than 0.05) during the study period. The differences in cross-brain oxygen extraction and global cerebral blood flow between infants who had neurologic recovery and those who died or sustained brain damage occurred in the presence of acceptable values for intracranial pressure, mean arterial pressure, and cerebral perfusion pressure. Our preliminary data suggest that cross-brain oxygen extraction and possibly global cerebral blood flow may be important variables associated with severe neuronal injury and death after hypoxic-ischemic cerebral injury.

Usefulness of (Tc 99m) HM-PAO scan in supporting clinical brain death in children: uncoupling flow and function.

OBJECTIVE: To determine the usefulness of (Tc 99m) HM-PAO scan in supporting the clinical diagnosis of brain death. DESIGN: Retrospective review. SETTING: Paediatric Intensive Care Unit. SUBJECTS: A total of 39 paediatric patients had HM-PAO scans conducted to confirm the presence of brain death or to assess the degree of brain injury. INTERVENTIONS: All patients had (Tc 99m) HM-PAO injected before the scan was conducted. MEASUREMENTS AND MAIN RESULTS: Fifty-four scans were done in 39 patients. The majority of cerebral injury was as a result of closed head injury or asphyxia/anoxia. There were 20 scans which demonstrated no cerebral blood flow (CBF); however, in 26 situations patients were clinically brain dead. All of the patients who continued to have CBF in the presence of clinical brain death sustained asphyxial/anoxic injuries. CONCLUSIONS: The HM-PAO scan is a useful non-invasive portable tool for supporting the diagnosis of brain death when there is absent CBF. However, continued flow may be present in asphyxial/anoxic injuries in the presence of clinical brain death.