Pediatric organ donation: impact of medical examiner refusal.

OBJECTIVES: To examine the national Pediatric Intensive Care Unit (PICU) experience regarding Medical Examiner (ME) refusal of organ procurement from potential donors. To review our experience regarding PICU mortalities, organ donation, and impact of the ME on the organ donation process. DESIGN: National survey of PICU directors requesting demographics, type of ME system, perceptions of ME responsiveness to organ donation, and data regarding potential donors and their outcomes. Also, a retrospective chart review of all PICU deaths from 1990 to 1992 at a tertiary care center, noting the number of potential organ donors, ME cases, those harvested, rejected, and reason for rejection. PARTICIPANTS: PICU directors selected from a list of Pediatric Section members of the Society of Critical Care Medicine. The response rate was 59%. The chart review was performed in a 1000-bed hospital with a 12-bed PICU. RESULTS: PICU directors' perceptions of ME responsiveness to organ donation were not determined by size of PICU, area served, type of hospital, ME system, or means of contacting the ME. ME refusal accounted for 15% and 16% of total refusals in the survey and chart review, respectively. Family refusal accounted for 49% and 28% in these same groups. Survey respondents' hints and suggestions to decrease denial and increase organ donation focused on improved communication (61% and 33%), and education (16% and 55%). CONCLUSIONS: ME refusal does impact on pediatric organ donation, but not as significantly as family refusal. Increased organ procurement in ME-related cases will require improved communication between MEs, physicians, and the Organ Procurement Organizations (OPOs).

Methemoglobin levels during prolonged combined nitroglycerin and sodium nitroprusside infusions in infants after cardiac surgery.

Nitroglycerin (NTG) and sodium nitroprusside (SNP) are routinely used perioperatively in infants with congenital heart defects. In this study, NTG and SNP were infused in the operating room to increase venous capacitance, reduce systemic and pulmonary afterload, facilitate weaning off cardiopulmonary bypass, stabilize hemodynamics for transport to the intensive care unit (ICU), and reduce the fluid resuscitation needed upon arrival in the ICU. Because of the risk for accumulation of methemoglobin (MetHb) and cyanmethemoglobin (cyan-MetHb) during prolonged continuous infusion of NTG and SNP, it was decided to (1) quantify ICU use, (2) measure % MetHb at 12-hour intervals, and (3) look indirectly for the accumulation of cyan-MetHb by comparing simultaneous pulse oximetry (SpO2) (Nellcor N-100 [Nellcor, Haywood, CO]) and CO-oximetry (SaO2) (Corning 270 [Corning, Medfield, MA]). A total of 69 arterial samples were obtained from 16 infants (median age 4.4 months) following cardiac surgery with bypass. Median doses of NTG, 6.0 mg/kg (range 0.7 to 27.5), and SNP, 3.3 mg/kg (range 0.6 to 33.4), were infused over a median of 64.5 hours (range 12 to 183) (N = 16 patients). The median MetHb was 0.6% (range 0.0 to 1.5) after infusions of NTG, 1.8 micrograms/kg/min (range 0.5 to 4), and SNP, 1.3 micrograms/kg/min (range 0.3 to 8.4) (N = 69 measurements). Regression analysis of oximetry data yielded the equation: SpO2 = 1.04 SaO2 - 3.7%, r = 0.97. The mean difference between SpO2 and SaO2 data pairs was 0.0% (bias) with a SD (precision) of +/- 2.3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Atlantooccipital subluxation in a neonate with Down's syndrome. Case report and review of the literature.

Atlantooccipital subluxation (AOS) occurs in up to 63% of patients with Down's syndrome. However, presenting symptoms and the age at which preoperative screening becomes necessary have not been clearly delineated. Recently, a 16-day-old female with Down's syndrome and AOS presented to our institution. Following patent ductus arteriosus ligation, her neurological examination revealed trace movement, few spontaneous respirations, and left lower extremity clonus. Cervical spine radiographs revealed significant AOS. She was reduced and underwent a fusion from the occiput to C2. She gradually regained full strength and sensation. This case is the youngest example of AOS related to Down's syndrome described. It emphasizes the need for preoperative screening of all patients with Down's syndrome.

Stridor: intracranial pathology causing postextubation vocal cord paralysis.

During an 18-month period in a pediatric intensive care unit, nine patients with vocal cord paralysis were identified using flexible bronchoscopy. When tracheally extubated, each child was found to have stridor. The children ranged in age from 17 days to 5 1/2 years. Two patients had unilateral paralysis, but neither required tracheostomy. Seven patients displayed bilateral abductor vocal cord paralysis. Of these, six patients required tracheostomy. Surgical injury to the recurrent laryngeal nerve was the probable cause in two patients. The other seven patients had neurologic disorders with documented or suspected increases of intracranial pressure. Four of the seven patients with bilateral abductor vocal cord paralysis regained cord mobility within 4 months. Both children with unilateral cord paralysis have no stridor and vocalize well 1 year later. Cord paralysis in the setting of intracranial hypertension probably results from compression or ischemia of the vagus nerve before it exits the skull. Early visualization of the larynx should be done in patients who become stridulous when extubated, especially those with prior thoracic procedures or with neurologic disorders associated with intracranial hypertension.

Dependence of oxygen consumption on oxygen delivery in children with hyperdynamic septic shock and low oxygen extraction.

We studied the effect of increasing systemic oxygen delivery (DO2) by packed RBC (PRBC) transfusion on oxygen consumption (VO2) in children with hyperdynamic septic shock. After routine resuscitation with volume loading and pharmacologic support, patients were studied if they had significant derangements of oxygen transport variables defined as: baseline VO2 less than 180 ml/min.m2 and oxygen extraction (O2 extr) less than 24%. Eight studies were performed. PRBC transfusion increased DO2 from 636 +/- 167 to 828 +/- 266 ml/min.m2 (p less than .01) without increasing cardiac index (5.2 +/- 1.3 vs. 5.0 +/- 1.4 L/min.m2). VO2 increased from 112 +/- 36 to 157 +/- 60 ml/min.m2 (p less than .01) while O2 extr was unchanged (18 +/- 3% vs. 19 +/- 6%). Despite initial low O2 extr, VO2 can be increased in pediatric septic shock by a further increase in DO2. Since VO2 correlates with survival, one should consider enhancing DO2 further despite initial low O2 extr and high DO2. Effects on morbidity and mortality require further study.

Trending of impedance-monitored cardiac variables: method and statistical power analysis of 100 control studies in a pediatric intensive care unit.

The NCCOM3-R6 monitor continuously monitors cardiac output and five other cardiovascular variables from the thoracic electrical bioimpedance signal. We averaged data over 5-min intervals for 130 min in 100 control studies in 40 pediatric ICU patients, age 0.04 to 20.39 yr (median 1.39) and weighing 2.0 to 59.5 kg (median 8.8). For individual studies, 99% of the 5-min averages of cardiac output fell within +/- 44% of the baseline cardiac output for that study. Normal ranges were somewhat narrower for the other five variables. When we averaged data for 100 studies, 5-min interval observations for each variable did not deviate from baseline over a 2-h period (p greater than .70). With a sample size of 100 studies, we could detect a change in cardiac output of +/- 5% at the p less than .005 level with a power of 0.95. We conclude that with a sufficiently large sample size, studies employing the NCCOM3 can detect clinically significant cardiovascular changes due to pharmacologic or procedural stressors.

Percutaneous catheterization of the axillary vein in infants and children.

The axillary vein was evaluated as an alternative access site for central venous catheterization in critically ill infants and children. Children were placed in the Trendelenberg position (when possible) with arm abducted 100 to 130 degrees. The vein was entered parallel and inferior to the artery. Success rate for catheterization was 79% (41/52). Catheter diameter range was 3 to 8.5 F and catheter length range was 5 to 30.5 cm. Median patient weight was 7.0 kg (3.0 to 59 kg). Median age was 0.91 years (14 days to 9 years). All central lines ended in the subclavian, innominate, or superior vena cava. Median catheter duration was 8 days (2 to 22 days). A total of 338 patient catheter-days were studied. Central venous pressure was successfully monitored in five of five attempts. Complications with insertion (3.8% of attempts) included one pneumothorax and one hematoma. Complications during catheter duration (9.8% of catheters, 1.1% per catheter-day) included one instance each of venous stasis, venous thrombosis, catheter sepsis, and parenteral nutrition infiltration. No complication contributed to a patient mortality. Success and complication rates were comparable with those in jugular catheterization studies in children. The axillary approach is an acceptable route for central venous catheterization in critically ill infants and children.

Age-related differences in the use of morphine, diazepam, and pancuronium for mechanically ventilated children.

Mechanically ventilated children usually require a combination of sedation (morphine = M, diazepam = D) and paralysis (pancuronium = P) to minimize anxiety, discomfort, and the risks of self-extubation, tracheal injury, and pulmonary barotrauma. We sought to determine whether our use of MDP varied with patient age. Cases where the dosage of MDP would be influenced by neurological, hemodynamic, or painful diagnoses were excluded. The 36 cases selected were divided according to age into three groups (less than 4 months = A, 4-18 months = B, greater than 18 months = C). The daily sum of MDP dosages was calculated for each of the 326 study days, a mean of 9 study days for each case. The median daily drug usage in group B (2.3 mg/kg/day) was twice that in either group A (younger) or group C (older) (both p less than 0.001). This finding may be explained by developmental changes in physiology, pharmacology, and behavior, and may have been influenced by a paradoxical drug effect or multiple drug antagonism.

Organ blood flow and cardiovascular effects of high-frequency oscillation versus conventional ventilation in dogs with right heart failure.

Mongrel dogs underwent a large (apex to pulmonary valve) right ventriculotomy to produce right ventricular dysfunction. Right ventriculotomy decreased cardiac output from 2.47 +/- 0.43 to 1.34 +/- 0.16 L/min (p less than .01), increased CVP from 3.7 +/- 1.5 to 8.3 +/- 2.4 mm Hg (p less than .01), and decreased mean systemic arterial pressure (MAP) from 143 +/- 16 to 121 +/- 21 mm Hg (p less than .01). There was no effect on mean pulmonary artery pressure (MPAP) or pulmonary artery occlusion pressure. After stabilization a randomized crossover controlled comparison of conventional mechanical ventilation (CMV) and high-frequency oscillation (HFO) was performed. FIO2, pH, PCO2, core temperature, and preload were held constant. Mean airway pressure (Paw) was 4.8 +/- 0.7 cm H2O on CMV vs. 3.5 +/- 1.0 cm H2O on HFO (p less than .05). There was no difference in PaO2. We found no statistically significant differences between the two modes of ventilation with respect to cardiac output, MAP, MPAP, systemic vascular resistance, and pulmonary vascular resistance. Blood flows to cerebral cortex, renal cortex, adrenal, hepatic artery, left ventricular myocardium, and skeletal muscle were not different when comparing CMV to HFO. Despite the ability to attain equivalent oxygenation and ventilation at lower Paw, HFO offers no hemodynamic advantage over CMV in the presence of right ventricular dysfunction.

Acute mechanical ventilation: an index of the absolute need for pediatric intensive care unit beds.

Acute mechanical ventilation (MV) is an absolute indication for pediatric ICU (PICU) admission. Only 28% of PICU patients over an 8-yr period required acute MV, yet these accounted for 52.5% of total patient days. Transport admissions were more likely to require acute MV (40.4%). Subgroups of MV patients differing significantly (p less than .01) in the median duration of intensive care included the following: a) under 2 years (5 days) vs. older (4 days); b) medical (5 days) vs. all perioperative (3 days); and c) cardiac surgery (3 days) vs. other perioperative (4 days). We found that a) an average of 3.79 PICU beds per million general population (1.39 per 100,000 children under age 18 yr) were occupied daily by acute MV patients; b) the total PICU bed occupancy averaged 7.54 beds per million general population (2.76 per 100,000 children under age 18 yr) or twice that needed for acute MV patients alone; and c) regression equations based on subgroup annual admissions accurately predicted annual variability in acute MV census/day at both the study and a comparison hospital.

Gastrografin aspiration in a 3 3/4-year-old girl.

A case of Gastrografin aspiration in a 3 3/4-year-old child admitted for multiple trauma is described.

Lack of evidence that formula-derived creatinine clearance approximates glomerular filtration rate in pediatric intensive care population.

During the four-year period from January 1980 to April 1984, 56 patients were admitted to the Pediatric Intensive Care Unit (PICU) whose care required timed urine collections using indwelling urinary catheters. The glomerular filtration rate derived from the clearance of endogenous creatinine with accurate timed urine volume is compared to that derived from the formula, 0.55 body length (cm)/plasma creatinine (mg/dl). There is a significant difference in the results between the two methods, p less than 0.0001. The largest divergence arises in those with creatinine clearance of less than 40 ml/min per 1.73 sq.m. In this subgroup, the formula derived glomerular filtration rates consistently overestimate the renal function and create a misleading assurance of minimal renal impairment. Therefore, our findings suggest that the latter formula is not applicable to PICU patients for consideration of fluid and electrolyte balance, administration of nephrotoxic drugs or criteria for dialysis.

Postictal pulmonary edema in children.

Pulmonary edema complicating generalized tonic-clonic seizures has rarely been reported in children, although it has been well documented in adults. We report two patients, aged 8 and 9 years, who developed clinical and radiographic evidence of the condition. Fever, leukocytosis, and arterial hypoxemia are seen in the absence of cardiac dysfunction or infection. Rapid and complete recovery is to be expected if supportive therapy is instituted. Since these patients had no underlying cardiac pathology, control of the seizures will prevent further episodes.

An angiographic catheter technique for selective endobronchial intubation.

Three children requiring selective endobronchial intubation were treated with a technique utilizing an angiographic catheter as a guide for the endotracheal tube. The procedure was successful in all three children and there were no long-term complications. Performed properly the technique is rapid, safe and avoids uncontrolled attempts at endobronchial intubation or the need for a flexible fiberoptic bronchoscope.

The anatomical heterogeneity of hearts lacking a patent communication between the left atrium and the ventricular mass ('mitral atresia') in presence of a patent aortic valve.

Thirty-five hearts were studied with no patent communication between the left atrium and the ventricular mass ('mitral atresia'). In ten, an imperforate and hypoplastic membrane separated the left atrium from a hypoplastic left ventricle. The imperforate valve ranged from a tiny membrane with no evidence of tension apparatus, through a larger membrane supported by muscular columns in the ventricular inlet portion, to an aneurysmal imperforate sac attached to a single hypoplastic papillary muscle. The ventriculo-arterial connection was concordant in nine of the ten hearts and double outlet from the right ventricle in one. In one further heart, there was double inlet left ventricle with imperforate left atrioventricular valve, a rudimentary right ventricle and ventriculo-arterial discordance. In the other 24 hearts the muscular floor of the left atrium was completely separated by the atrioventricular sulcus from the ventricular mass (absent left atrioventricular connection). In 11 of these hearts, the right atrium was connected to a right ventricle and there was a posterior and left-sided rudimentary left ventricular chamber which had no connection with the atrial chambers. The left ventricle supported the aorta in five of the 11 hearts, but in the other six it was simply a pouch of left ventricular morphology. In ten cases the right atrium was connected to a dominant left ventricle. An anterior rudimentary right ventricle was present in each but had no connection with the atrial chambers. It was to the left of the left ventricle in seven, directly anterior in one and to the right in two cases. The right ventricle supported the aorta in eight cases, the pulmonary trunk in one and neither great artery in the remaining case. Lastly, there were three cases in which a sole ventricular chamber of indeterminate morphology was present and gave rise to both great arteries.

Urea nitrogen excretion in critically ill children.

Urinary urea nitrogen (UUN) excretion as an index of both total nitrogen excretion and protein catabolism was assayed in 32 children (aged 2 months to 15 years, median 6 years) (50% mechanically ventilated) during an intensive care unit course of one to ten days (median three days). The daily UUN excretion was 4.38 +/- 2.22 gm/sq m (171 +/- 89 mg/kg) (N = 121 patient days). The average daily UUN excretion (N = 32 children) was well described by a linear regression equation for square meters of body surface area (BSA) (milligrams of UUN = 4,421.5 x BSA; r2 = .903). This linear relationship permitted the valid comparison of both individuals and subgroups despite wide age differences. Excretion data in the mechanically ventilated vs the spontaneously breathing children, and in four diagnostic subgroups (Reye syndrome, seven; sepsis, six; elective surgery, seven; and miscellaneous, 12) were evenly distributed about the regression line for body surface area. Variability in average daily UUN excretion was on individual basis, and was independent of diagnostic or therapeutic subgroup.

Carotid artery bruits: prevalence survey and differential diagnosis.

From a 10% sampling of the Olmsted County, Minnesota, population, persons of age 45 years and older were selected randomly in predetermined age and sex groupings and examined for cervical murmurs. Five hundred nine persons representing approximately 1% of all persons in the population between 45 and 54 years old, 2.5% of those 55 to 64 years old, and 3.5% of those more than 65 years old were included in the study. A cervical murmur of some type was heard in 64 persons (12.6%). Localized, midcarotid bifurcation bruits were noted in 22 persons (4.3%). Of this last group, 15 persons (2.9%) were asymptomatic. The prevalence of localized, asymptomatic carotid arterial bruits increased with age: 0.9% at 45 to 54 years, 2.1% at 55 to 64 years, 3.8% at 65 to 74 years, and 5% at 75 years and older; it was higher in females (4.4%) than in males (1.6%).