Robert K. Kanter

Mortality associated with multiple organ system failure and sepsis in pediatric intensive care unit

Seven hundred twenty-six patients from five pediatric intensive care units were studied to determine the association of multiple organ system failure (MOSF) with mortality and to test the hypothesis that MOSF associated with sepsis has a higher mortality rate than MOSF without sepsis. There were 177 (24%) patients with MOSF and 83 (11%) nonsurvivors of MOSF. The mortality rates for two, three, or four or more failed organ systems were 26%, 62%, and 88%, respectively (P less than 0.001). Eighty-four (47%) patients with MOSF had associated sepsis. Sepsis (both bacteremia and clinical sepsis syndrome) did not significantly increase mortality rates in the groups with organ system failure. Mortality rates for patients with sepsis before or within 24 hours of development of MOSF (early sepsis) did not differ from mortality rates for those patients with onset of sepsis more than 24 hours after developing MOSF (late sepsis, 53% vs 33%, P = NS). We conclude that underlying pathophysiologic mechanisms of MOSF other than sepsis are as important as sepsis in critically ill pediatric patients.

Reduction of morbidity in interhospital transport by specialized pediatric staff

ObjectiveWe prospectively compared the occurrence of morbidity during high-risk interhospital transport in two types of transport systems: specialized tertiary center-based vs. nonspecialized, referring hospital-based. DesignConcurrent, prospective comparison of morbidity at two pediatric centers that use different types of transport team. SettingTwo tertiary care pediatric intensive care units (ICU). The specialized team consisted of a pediatric resident, pediatric intensive care nurse, and a pediatric respiratory therapist. Comparison was made with referring institution transports by nonspecialized personnel to a second center. The two centers were similar in size and patient mix, with referral areas of similar population and rural/urban ratio. PatientsOne hundred forty-one patients transported to two tertiary pediatric ICUs. InterventionsNone. Measurements and Main ResultsTwo types of events were assessed: vital signs and other observable clinical events were described as “physiologic deteriorations.” Events such as loss of intravenous access, endotracheal tube mishaps, and exhaustion of oxygen supply were described as “intensive care-related adverse events.” Pretransport severity of illness and therapy were described by Pediatric Risk of Mortality (PRIoM) and Iherapeutic Intervention Scoring System (TISS) scores. Only high-risk patients with PRISM scores of >10 were analyzed.Intensive care-related adverse events occurred in one (2%) of 49 transports by the specialized team and 18 (20%) of 92 transports by nonspecialized personnel. The difference is statistically significant (p < .05). Physiologic deterioration was similar in the two groups occurring in five (11%) of 47 specialized team transports and 11 (12%) of 92 transports by the nonspecialized team. ConclusionWe conclude that specialized pediatric teams can reduce transport morbidity. This is the first published study to compare two models of pediatric transport using identical definitions of severity and morbidity. (Crit Care Med 1994; 22:1186–1191)

Malnutrition in Critically III Infants and Children

The prevalences of acute and chronic protein-energy malnutrition (PEM) and deficiencies in stores of fat and somatic protein have not been previously examined in a pediatric intensive care unit. One hundred eight nutritional assessments were performed using anthropometric techniques on infants and children in a multidisciplinary intensive care unit. Overall, the prevalence of acute PEM was 19% and chronic PEM was 18%. The prevalence of fat store depletion was 14% and somatic protein store depletion was 21%. In general, children <2 years had poorer nutritional status compared to children ≥2 years. There was not a statistically significant difference between medical and surgical patients. It is concluded that PEM and deficiencies in the macronutrient stores of fat and somatic protein are common in critically ill infants and children.

Infectious complications and duration of intracranial pressure monitoring.

We studied 65 children with acute brain injury to determine how the risk of infectious complications changed with duration of intracranial pressure (ICP) monitoring. More than half of the 72 monitors inserted in these patients were in place at least 7 days (range 1 to 28). Nine infections occurred on days 2 through 11. The overall risk was 1.5 infections per 100 monitor-days. After day 6 the risk of subsequent infection diminished, as did the percent of monitors which subsequently became infected. The declining risk of infection over time suggests that infection is introduced at the time of monitor insertion. These findings justify a protocol in which a single ICP monitoring device is used as long as necessary, with reinsertion of a new monitor only if a malfunction occurs, or if daily surveillance cultures demonstrate an infection. Routine reinsertion of a new monitor might increase risk by unnecessarily re-exposing the patient to contamination at the time of insertion.

Pediatric Hospital and Intensive Care Unit Capacity in Regional Disasters: Expanding Capacity by Altering Standards of Care

BACKGROUND. Federal planners have suggested that one strategy to accommodate disaster surges of 500 inpatients per million population would involve altering standards of care. No data are available indicating the extent of alterations necessary to meet disaster surge targets. OBJECTIVE. Our goal was to, in a Monte Carlo simulation study, determine the probability that specified numbers of children could be accommodated for PICU and non-ICU hospital care in a disaster by a set of strategies involving altered standards of care. METHODS. Simulated daily vacancies at each hospital in New York City were generated as the difference between peak capacity and daily occupancy (generated randomly from a normal distribution on the basis of empirical data for each hospital). Simulations were repeated 1000 times. Capacity for new patients was explored for normal standards of care, for expansion of capacity by a discretionary 20% increase in vacancies by altering admission and discharge criteria, and for more strictly reduced standards of care to double or quadruple admissions for each vacancy. Resources were considered to reliably serve specified numbers of patients if that number could be accommodated with a probability of 90%. RESULTS. Providing normal standards of care, hospitals in New York City would reliably accommodate 250 children per million age-specific population. Hypothetical strict reductions in standards of care would reliably permit hospital care of 500 children per million, even if the disaster reduced hospital resources by 40%. On the basis of historical experience that as many as 30% of disaster casualties may be critically ill or injured, existing pediatric intensive care beds will typically be insufficient, even with modified standards of care. CONCLUSIONS. Extending resources by hypothetical alterations of standards of care would usually satisfy targets for hospital surge capacity, but ICU capacity would remain inadequate for large disasters.

Prolonged mechanical ventilation of infants after open heart surgery

Records of 140 infants younger than 2 yr of age who had undergone open heart surgery were studied to evaluate the duration of postoperative mechanical ventilation (MV), to determine the relationship between prolonged MV and mortality, and to identify variables predisposing the patient to prolonged MV. MV was required beyond the first postoperative day in 56 infants, and was prolonged for at least 7 days in 19 infants. Mortality was approximately the same (16% to 17%) whether or not MV was required for more than 7 days. Preoperative and intraoperative variables associated with longer MV included younger age, longer cardiopulmonary bypass time, longer aortic cross-clamp time, and preoperative MV. Multiple predisposing factors increased the probability of prolonged MV. Postoperative variables including premature extubation and a second surgical procedure also were associated with prolonged MV. The consequences of prolonged MV may be minimized by early nutritional support, aggressive surveillance for treatable complications, and avoidance of premature extubation.

Strategies to improve pediatric disaster surge response: potential mortality reduction and tradeoffs

Objective: To estimate the potential for disaster mortality reduction with two surge response strategies: 1) control distribution of disaster victims to avoid hospital overcrowding near the scene, and 2) expand capacity by altering standards of care to only “essential” interventions. Design: Quantitative model of hospital mortality. Setting: New York City pediatric intensive care unit and non–intensive care unit pediatric hospital capacity and population. Measurements and Main Results: Mortality was calculated for a hypothetical sudden disaster, of unspecified mechanism, assuming 500 children per million population need hospitalization, including 30% severely ill/injured warranting pediatric intensive care unit care, with high (76%) predisaster hospital occupancy. Triage rules accommodated patients at lower levels of care if capacity was exhausted. Specified higher relative mortality risks were assumed with reduced levels of care. In a pessimistic baseline scenario, hospitals near the disaster scene, considered to have 20% of regional capacity, were overcrowded with 80% of the surge patients. Exhausted capacity at overcrowded hospitals near the scene would account for most of the 45 deaths. Unused capacity would remain at remote facilities. If regional surge distribution were controlled to avoid overcrowding near the scene, then mortality would be reduced by 11%. However, limited pediatric intensive care unit capacity would still require triage of many severe patients to non–intensive care unit care. Instead, if altered standards of care quadrupled pediatric intensive care unit and non–intensive care unit capacity, then mortality would fall 24% below baseline. Strategies 1 and 2 in combination would improve mortality 47% below baseline. If standards of care were altered prematurely, preventable deaths would occur. However, additional simulations varying surge size, patient severity, and predisaster occupancy numbers found that mortality tradeoffs would generally favor altering care for individuals to improve population outcomes within the range of federal planning targets (500 new patients/million population). Conclusion: Quantitative simulations suggest that response strategies controlling patient distribution and expanding capacity by altering standards of care may lower mortality rates in large disasters.

Regional variation in child mortality at hospitals lacking a pediatric intensive care unit.

Objective To investigate statewide variation in failure to utilize existing regional pediatric intensive care units (PICUs). Methods Deaths of children in hospitals lacking specialized units (non-PICU hospitals) were postulated to represent possible PICU utilization failures. A survey study was performed on hospital inpatient discharges and deaths in 1997, using data obtained from the New York Statewide Planning and Research Cooperative System (SPARCS). Children 0–14 yrs old were studied, excluding neonatal Diagnosis-Related Groups and emergency department deaths. Hospitals were considered to have a PICU if they had a board-certified pediatric intensivist on staff, and either New York State designation as a PICU or a separate dedicated unit for children. Non-PICU hospital pediatric death rates were compared for health service areas to determine whether regional variation occurred. Results Statewide, 157 of 584 (27%) pediatric hospital inpatient deaths occurred in non-PICU hospitals. Significant variation was seen among eight regions in pediatric death rates in non-PICU hospitals (p < .05). The 114 of 328 (35%) New York City inpatient deaths occurring in non-PICU hospitals significantly exceeded the 43 of 256 (17%) throughout the remainder of the state (p < .05). New York City non-PICU hospital death rates also were higher than in the rest of the state, when expressed per 100,000 pediatric population (8.04 vs. 2.00), and per 1,000 non-PICU hospital discharges (2.25 vs. 1.18), respectively (p < .05). Forty percent of New York City non-PICU hospitals experienced a pediatric inpatient death compared with only 13% in the rest of the state (p < .05). Conclusions Although the death of some children in hospitals lacking a PICU is expected, the significant regional variation in these deaths suggests that local obstacles, perhaps unique to metropolitan areas, may interfere with access to existing pediatric critical care resources.

A comparison of infant ventilation methods performed by prehospital personnel

By comparing mouth-to-mouth ventilation to other methods, we tested whether there are significant differences among infant mannequin ventilation methods performed by emergency medical technicians-paramedics (EMT-Ps). Fifty-nine participants were evaluated in the performance of six ventilation methods; methods studied were mouth-to-mouth; two mouth-to-mask devices; and infant, pediatric, and adult bag-valve-mask devices. By measuring each breath, the percentage of acceptable ventilations in predetermined ranges, 5 to 25 mL/kg or 10 to 20 mL/kg, was calculated. Methods were compared using repeat measures ANOVA testing. Correlation between ventilation performance and the experience of personnel was expressed as the Pearson correlation coefficient. There were no significant differences in performance between methods, except for inadequate ventilation with the Laerdal Pocket Mask (P less than .05) from poor mask fit. The correlation between years of prehospital experience and the number of resuscitations versus ventilation performance was poor. Single rescuer, EMT-Ps can successfully ventilate an infant mannequin with various size resuscitation bags. The Laerdal Pocket Mask is an ineffective device for infant mannequin ventilation and should not be recommended for infant resuscitation.

Comparison of neurons in rat medulla oblongata with Fos immunoreactivity evoked by seizures, chemoreceptor, or baroreceptor stimulation

Neurons in rat medulla oblongata with Fos immunoreactivity as a marker of synaptic excitation evoked by pentylenetetrazole-induced seizures were compared with cell populations activated by the stimulation of chemoreceptor and baroreceptor afferent pathways. Chemoreceptors were stimulated by placing rats in a hypoxic gas mixture (7% oxygen) for 2 h. Baroreceptors were activated by phenylephrine-induced hypertension. Seizures and hypoxia induced Fos immunoreactivity in neurons with similar anatomical distributions in the nucleus tractus solitarius, dorsal motor nucleus of the vagus, and ventrolateral medulla. Hypertension was associated with Fos immunoreactivity in an overlapping anatomical distribution compared to seizures and hypoxia, but in a more restricted pattern. A similar proportion of catecholaminergic cells of medulla oblongata (cells immunoreactive for catecholamine synthetic enzymes, tyrosine hydroxylase or phenylethanolamine-N-methyltransferase) had Fos immunostaining after seizures and hypoxia (P > 0.05), while significantly fewer were activated by hypertension (P < 0.05). The majority of tyrosine hydroxylase-immunoreactive cells in caudal ventrolateral medulla were activated by both seizures and hypoxia (mean per cents, 79 and 67%, respectively). Since cell populations activated by seizures and hypoxia are indistinguishable, and a majority of tyrosine hydroxylase-reactive cells in caudal ventrolateral medulla are independently activated by each stimulus, it may be inferred that some impulses originating from seizures and chemoreceptor afferent pathways converge to a common set of neurons. These observations identify neurons in rat medulla oblongata which may mediate the impact of seizures on central processing of chemoreceptor afferent activity.