Recurring BALB/c mouse lung inflammatory responses to episodic allergen exposure.

This study detailed the sequence of recurring inflammatory events associated with episodic allergen exposures of mice resulting in airway hyperreactivity, sustained inflammation, goblet-cell hyperplasia, and fibrogenesis that characterize a lung with chronic asthma. Ovalbumin (OVA)-sensitized female BALB/c mice were exposed to saline-control or OVA aerosols for 1 h per day for episodes of 3 d/wk for up to 8 wk. Lung inflammation was assessed by inflammatory cell recoveries using bronchoalveolar lavages (BAL) and tissue collagenase dispersions. Cell accumulations were observed within airway submucosal and associated perivascular spaces using immunohistochemical and tinctorial staining methods. Airway responsiveness to methacholine aerosols were elevated after 2 wk and further enhanced to a sustained level after wk 4 and 8. Although by wk 8 diminished OVA-induced accumulations of eosinophils, neutrophils, and monocyte-macrophages were observed, suggesting diminished responsiveness, the BAL recovery of lymphocytes remained elevated. Airway but not perivascular lesions persisted with a proliferating cell population, epithelial goblet-cell hyperplasia, and evidence of enhanced collagen deposition. Examination of lung inflammatory cell content before the onset of the first, second, and fourth OVA exposure episodes demonstrated enhancements in residual BAL lymphocyte and BAL and tissue eosinophil recoveries with each exposure episode. Although tissue monocyte-macrophage numbers returned to baseline prior to each exposure episode, the greatest level of accumulation was observed after wk 4. These results provide the basis for establishing the inflammatory and exposure criteria by which episodic environmental exposures to allergen might result in the development of a remodeled lung in asthma.

In vivo efficacy of dendrimer-methylprednisolone conjugate formulation for the treatment of lung inflammation.

Dendrimers are an emerging class of nanoscale intracellular drug delivery vehicles. Methylprednisolone (MP) is an important corticosteroid used in the treatment (through inhalation) of lung inflammation associated with asthma. The ability of MP-polyamidoamine (PAMAM) dendrimer conjugate to improve the airway delivery was evaluated in a pulmonary inflammatory murine model that was based on an 11-fold enhancement of eosinophil lung accumulation following five daily inhalation exposures of sensitized mice to the experimental allergen, ovalbumin. MP was successfully conjugated to PAMAM-G4-OH dendrimer yielding 12 MP molecules per dendrimer, and further solubilized in lysine carrier. Five daily trans-nasal treatments with the carrier alone, free MP, and MP-dendrimer at 5 mg kg(-1) (on a drug basis) did not induce additional lung inflammation, although free MP decreased baseline phagocytic cell recoveries by airway lavage and tissue collagenase dispersion. MP treatments alone decreased ovalbumin-associated airway and tissue eosinophil recoveries by 71 and 47%, respectively. Equivalent daily MP dosing with MP-dendrimer conjugate further diminished these values, with decreases of 87% and 67%, respectively. These findings demonstrate that conjugation of MP with a dendrimer enhances the ability of MP to decrease allergen-induced inflammation, perhaps by improving drug residence time in the lung. This is supported by the fact that only 24% of a single dose of dendrimer delivered to the peripheral lung is lost over a 3-day period. Therefore, conjugation of drugs to a dendrimer may provide an improved method for retaining drugs within the lung when treating such inflammatory disorders as asthma.

Speech and phonological characteristics of individual children with a history of tracheostomy.

The present investigation studied the speech production and phonological skills of 6 children between the ages of 2;8 and 6;8 (years;months) who had undergone tracheostomy before age 8 months. Each child's speech was analyzed for size and composition of phonetic inventory, use of phonological processes, production of vowels, and production of the voicing contrast for stops. Analyses were completed once consistent air support for vocalization was established for each child and 3 months after that date. This study highlights the slow development of sound acquisition, vowel production, and the distinction between voiced and voiceless stops for some, but not all, children with a history of tracheostomy. Each child exhibited his or her own pattern of speech production difficulties on four tasks. Excessive use of inappropriate phonological processes relative to age was the most prevalent speech production problem. Five of 6 subjects exhibited clinically significant use of Stridency Deletion, Liquid Deviation, and/or Cluster Reduction. Adjustments were noted in the speech of all subjects during a 3-month period.

Enantiomer-selective pharmacokinetics and metabolism of ketorolac in children.

OBJECTIVE: To compare the pharmacokinetics and metabolism of R(+)- and S(-)- ketorolac in children. METHODS: Children from 3 to 18 years old received 0.6 mg/kg racemic ketorolac intravenously. Serial blood samples were obtained for 12 hours, and urine was collected for 12 to 24 hours. Racemic ketorolac was measured in plasma, and racemic ketorolac, para-hydroxyketorolac, and ketorolac glucuronide were measured in urine by HPLC. S(-)- and R(+)-ketorolac were measured in plasma; S(-)- and R(+)-ketorolac and ketorolac glucuronide were measured in urine by chiral HPLC separation. Plasma pharmacokinetic parameters for racemic drug and both enantiomers were determined for each patient. RESULTS: Clearance of racemic ketorolac in children was approximately 2 times the clearance reported in adults. Clearance of the S(-) enantiomer was 4 times that of the R(+) enantiomer. Terminal half-life of S(-)-ketorolac was 40% that of the R(+) enantiomer, and the apparent volume of distribution of the S(-) enantiomer was greater than that of the R(+) form. Recovery of S(-)-ketorolac glucuronide was 2.3 times that of the R(+) enantiomer. CONCLUSION: The higher clearance in children suggests that the weight-adjusted dose of ketorolac may have to be greater for children to achieve plasma concentrations comparable to those of adults. Because of the greater clearance and shorter half-life of S(-)-ketorolac, pharmacokinetic predictions based on racemic assays may overestimate the duration of pharmacologic effect. Enantiomeric pharmacokinetic differences are best explained by stereoselective plasma protein binding. Selective glucuronidation of the S(-) enantiomer suggests that stereoselective metabolism may also be a contributing factor.

Syndrome of inappropriate antidiuretic hormone secretion in children following spinal fusion.

OBJECTIVES: a) To determine if antidiuretic hormone (ADH) is elevated in patients undergoing spinal fusion, especially in those who have clinical evidence of syndrome of inappropriate antidiuretic hormone (SIADH); b) to evaluate the relationship between ADH secretion and the secretion of atrial natriuretic peptide (ANP). SETTING: Tertiary care pediatric intensive care unit (ICU) in a university hospital. DESIGN: A prospective cross-sectional, observational study with factorial design. PATIENTS: Thirty patients > or = 10 yrs of age undergoing spinal fusion admitted to the ICU for postoperative care. INTERVENTIONS: Patients underwent anterior, posterior, or both anterior/posterior spinal fusion. Blood was collected for serial measurements of ADH, ANP and serum electrolyte levels. Heart rate, blood pressure and central venous pressure were measured. MEASUREMENTS AND MAIN RESULTS: Thirty children were studied. Nineteen had idiopathic scoliosis, nine had neuromuscular scoliosis, one had Marfan's disease, and one had congenital scoliosis. Ten (33%) children met clinical criteria of SIADH. There was no difference in duration of surgery, blood loss, volume of iv fluid administration pre- and intraoperatively, or type of scoliosis between those who developed SIADH and those who did not. Hemodynamic variables were similar in both groups. ADH levels increased in both groups immediately postoperatively and at 6 hrs after surgery, but were much more elevated in those patients with SIADH. Patients with SIADH also had significantly higher ADH levels preoperatively. In relation to serum osmolality, ADH was considerably higher in those with SIADH compared with those who did not. Although ANP values tended to be higher in the group with SIADH, this did not reach statistical significance. CONCLUSION: SIADH occurs in a subset of children who undergo spinal fusion. The diagnosis of SIADH can be made easily using clinical parameters which are well-defined. In the face of SIADH, continued volume expansion may be harmful, and should therefore be avoided.

A randomized comparison of ketorolac tromethamine and morphine for postoperative analgesia in critically ill children.

OBJECTIVES: To evaluate the efficacy of a single dose of ketorolac compared with morphine for the relief of pain in children, and to determine the safety of ketorolac. SETTING: Tertiary pediatric intensive care unit in a university-affiliated hospital. DESIGN: Prospective, randomized, double-blind, parallel, single-dose, positive control study. PATIENTS: Children admitted to the intensive care unit with postoperative pain. INTERVENTIONS: Patients received a single dose of either morphine or ketorolac as the first postoperative analgesic when the pain score indicated significant pain. Blood pressure, heart rate, and urine output were recorded, as well as blood urea nitrogen, creatinine, bleeding time, hematuria or proteinuria, and aspartate aminotransferase. Side effects such as nausea and vomiting were noted. Morphine was used for rescue treatment if the patient continued to have significant pain > or =30 mins after study drug administration. MEASUREMENTS AND MAIN RESULTS: Of the 102 children studied, 48 received morphine and 54 received ketorolac. The percentage of patients reporting pain relief in the first and second hours after drug administration was not different between groups. Likewise, the proportion of patients who met the criteria for pain relief during the entire evaluation period was not different between groups. There was a trend toward fewer patients who received ketorolac requiring remedication in the first 4 hrs compared with those who received morphine, but this trend did not reach statistical significance. More patients in the morphine group failed to achieve pain relief at any time after the dose compared with those who received ketorolac. There were no differences between the two groups in physiologic or laboratory variables. Vomiting was more common in patients who received ketorolac. CONCLUSION: Ketorolac is comparable to morphine in relief of postoperative pain in children. A single dose of ketorolac does not result in abnormal postoperative bleeding or alter renal function. However, ketorolac may cause nausea and vomiting in some patients.

A child with cardiogenic shock and supraventricular tachycardia presenting in normal sinus rhythm.

We report a case of an infant who presented in profound cardiovascular collapse with a normal sinus rhythm initially. A diagnosis of supraventricular tachycardia (SVT) was established only after hemodynamic stabilization. The possibility of SVT being masked because of severe metabolic derangements and/or painful therapeutic procedures should be kept in mind when managing cardiogenic shock in children. Such a consideration is of practical significance in planning therapy, such as the avoidance of digitalis in a patient with Wolf-Parkinson-White syndrome.

Idiopathic pulmonary hemorrhage in infancy. Clinical features and management with high frequency ventilation.

STUDY OBJECTIVES: To describe the clinical characteristics of infants with severe acute pulmonary hemorrhage and the effects of mechanical ventilation on gas exchange. SETTING: Tertiary care pediatric ICU in a university hospital. PATIENTS AND DESIGN: Case records of patients with severe acute pulmonary hemorrhage from January 1992 to July 1995 were reviewed. Acute pulmonary hemorrhage was defined as hemoptysis and/or epistaxis or blood obtained from endotracheal tube which could not be attributed to cardiac or vascular malformation, infectious process, or known trauma. INTERVENTIONS: Patients were initially managed with conventional ventilation. High frequency ventilation (HFV) was utilized when hypoxemia (PaO2/PAO2 < 0.2) and/or respiratory acidosis (PaCO2 > or = 60 mm Hg with pH < 7.25) persisted. MEASUREMENTS AND RESULTS: Six African-American male infants from Detroit, with a median age 2.3 months, presented with severe acute pulmonary hemorrhage. Chest radiographs showed diffuse bilateral infiltrates or opacification with a normal sized heart. All infants were managed with HFV, four by oscillation and two by jet. The indications for HFV were persistent hypoxemia (2), respiratory acidosis (1), and a combination of both (3). There was an improvement in pH and PaCO2, and a decreased need for oxygen 6 and 24 h after initiating HFV. PaO2/PAO2 and oxygenation index showed a tendency toward improvement. All infants survived, and there were no complications. No cause for pulmonary hemorrhage was found in any of the infants. CONCLUSIONS: Idiopathic acute pulmonary hemorrhage is a potentially life-threatening disorder encountered among inner-city infants. HFV is highly effective and safe in rapidly reversing the severe oxygenation and ventilation deficits in this setting.

Predicting outcome in children with severe acute respiratory failure treated with high-frequency ventilation.

OBJECTIVES: a) To demonstrate the effect of high-frequency ventilation on gas exchange in children with severe acute respiratory failure unresponsive to conventional ventilation; b) to identify patients at high risk of death early after institution of high-frequency ventilation. SETTING: Tertiary care pediatric intensive care unit in a university hospital. DESIGN: A cross-sectional, observational study with factorial design. PATIENTS: Thirty-one patients with severe acute respiratory failure defined as a Pao2/F1o2 of < 150 torr (< 20 kPa) with a positive end-expiratory pressure of > or = 8 cm H2O and/or Paco2 of > 60 torr (> 8 kPa) with an arterial pH < 7.25. INTERVENTIONS: Patients received either high-frequency oscillation or jet ventilation if respiratory failure was unresponsive to conventional ventilation and if the underlying disease process was deemed reversible. MEASUREMENTS AND MAIN RESULTS: Thirty-one children were managed with high-frequency ventilation, 11 children with jet and 20 children with oscillator. Arterial blood gases and level of ventilatory support were recorded before and at 6, 24, 48, 72, and 96 hrs after institution of high-frequency ventilation. There was an improvement in an arterial pH, Paco2, Pao2, and Pao2/FID2 6 hrs after institution of high-frequency ventilation (p < .01). This improvement, along with decreased need for oxygen, was sustained through the subsequent course. Twenty-three (74%) of 31 children treated with high-frequency ventilation survived. Survivors showed an increase in an arterial pH, Pao2, Pao2/FIO2, and a decrease in Paco2 within 6 hrs, whereas nonsurvivors did not. Oxygenation index was the best predictor of outcome. A combination of an initial oxygenation index of > 20 and failure to decrease the oxygenation index by > 20% by 6 hrs after initiation of high-frequency ventilation predicted death with 88% (7/8) sensitivity and 83% (19/23) specificity, with an odds ratio of 33 (p = .0036, 95% confidence interval 3-365). CONCLUSIONS: In patients with potentially reversible underlying diseases resulting in severe acute respiratory failure that is unresponsive to conventional ventilation, high-frequency ventilation improves gas exchange in a rapid and sustained fashion. The magnitude of impaired oxygenation and its improvement after high-frequency ventilation can predict outcome within 6 hrs.

Adult respiratory distress syndrome in children.

In spite of modern technological advances, ARDS continues to be an important cause of morbidity and mortality from a diverse group of disorders such as sepsis, trauma, and aspiration. ARDS represents a target organ injury resulting from activation of the host's inflammatory cells and uncontrolled liberation of inflammatory mediators. In most instances, therefore, ARDS is a localized manifestation of a widespread onslaught characteristic of SIRS. At this time, there are no proven interventions to prevent ARDS, and the management is mainly supportive. Modulation of the host's inflammatory response seems to hold the most promise for prevention and treatment of ARDS. Such strategies need to be explored with well-controlled clinical trials.

Aerosolized ribavirin in mechanically ventilated children with respiratory syncytial virus lower respiratory tract disease: a prospective, double-blind, randomized trial.

OBJECTIVE: To study the effect of ribavirin aerosol therapy on the immediate clinical course of mechanically ventilated children with respiratory syncytial virus lower respiratory tract disease. DESIGN: Prospective, randomized, double-blind, placebo-controlled study. SETTING: Pediatric intensive care unit (ICU) of a university teaching hospital. PATIENTS: Forty-one children requiring mechanical ventilation for respiratory syncytial virus lower respiratory tract disease. INTERVENTIONS: Patients were stratified by the presence or absence of and underlying disease and then randomized to receive aerosolized ribavirin (20 mg/mL) or saline for 18 hrs/day for 5 days or until endotracheal extubation, whichever came first. MEASUREMENTS AND MAIN RESULTS: Dependent variables included the time course of the illness and the change in FIO2, ventilatory rate, PaO2/FIO2 ratio, and ventilatory-efficiency index of patients while they received aerosol therapy. Ribavirin- and placebo-treated patient groups were not significantly different in the number of ventilator days (6.4 +/- 6.9 vs. 8.2 +/- 10.1; p = .5), oxygen days (10.8 +/- 7.7 vs. 12.2 +/- 11.8; p = .9), ICU days (7.9 +/- 7.0 vs. 10.3 +/- 11.0; p = .7), or hospital days (12.9 +/- 9.7 vs. 16.2 +/- 14.0; p = .6) after the initiation of aerosol therapy. The change in FIO2, ventilatory rate, PaO2/FIO2 ratio, or ventilatory-efficiency index did not differ between the two groups. No ventilator malfunction was observed. There were six deaths caused by intractable hypoxemia in patients with underlying cardiopulmonary disease. Four of these deaths were in the placebo group and two in the ribavirin group (p = .5). CONCLUSIONS: Ribavirin aerosol therapy can be safely administered to mechanically ventilated children with severe respiratory syncytial virus lower respiratory tract disease. However, this therapy does not appear to affect immediate clinical outcome in such patients.

Transporting the neurologically compromised child.

The initial evaluation, stabilization, and subsequent transport of the neurologically compromised child should take into account the pathophysiologic response of the CNS to a variety of injurious factors. Little can be done to avoid neuronal damage from the primary event. Secondary insults resulting from hypoxemia, ischemia, intracranial hypertension, and fluid shifts can and must be prevented to ensure maximum neuronal salvage, however. Maintenance of an adequate airway, breathing, and circulation assume an immediate and ongoing priority. Neuroresuscitation should be directed toward reversing alterations in cerebral metabolism, autoregulation, brain water, and ICP associated with individual pathologic states.

Limitations of the Glasgow Coma Scale in predicting outcome in children with traumatic brain injury.

OBJECTIVE: To study the hypothesis that, in the absence of an ischemic-hypoxic state, children with severe traumatic brain injury and with unfavorable Glasgow Coma Scale scores may have good recovery. DESIGN: Retrospective, observational, cross-sectional study with factorial design. SETTING: Inpatient population in a university hospital. PATIENTS: Seventy-nine children with traumatic brain injury admitted to the intensive care unit. INTERVENTIONS: All patients received close monitoring and strict control of intracranial pressure (less than 20 mm Hg) and cerebral perfusion pressure (greater than 60 mm Hg). MEASUREMENTS AND RESULTS: Admission Glasgow Coma Scale score, survival, need for cardiopulmonary resuscitation, presence of shock, peak intracranial pressure, duration of coma, Glasgow Outcome Scale score, and the results of neuropsychologic tests were analyzed. Of 79 children, 70 (89%) survived. Although the mortality rate was higher among patients with Glasgow Coma Scale scores of 3 to 5, 14 (64%) of 22 of these children survived. Nonsurvivors had a significantly higher incidence of shock and need for cardiopulmonary resuscitation. Except for two patients who had prolonged hypoxemia, all children, including those with Glasgow Coma Scale scores of 3 to 5, had a satisfactory outcome (Glasgow Outcome Scale scores of 4 or 5). Neuropsychologic outcome was not significantly different in the survivors with Glasgow Coma Scale scores of 3 to 5 and those with Glasgow Coma Scale scores of 6 or more. CONCLUSIONS: A low Glasgow Coma Scale score does not always accurately predict the outcome of severe traumatic brain injury; in the absence of hypoxic-ischemic injury, children with traumatic brain injury and Glasgow Coma Scale scores of 3 to 5 can recover independent function.

The role of intensive care in managing childhood cancer.

To study the value of intensive care in childhood cancer, we evaluated the clinical course and outcome of all such children admitted to our intensive care unit (ICU) (n = 183) during the five-year period from 1984-1988. Excluding those admitted for postoperative observation, there were a total of 63 admissions for complications of malignancy. Of these, admissions for sepsis, pulmonary parenchymal disease, or coma were associated with poor outcome. Thirty-six percent of patients requiring mechanical ventilation for respiratory failure and 27% requiring inotropic support survived longer than six months. Physiologic Stability Index and Therapeutic Intervention Scores were significantly greater in nonsurvivors than survivors. Of those who survived their ICU stay, 50% went home functioning at their premorbid state. The duration of ICU stay was not different in survivors and nonsurvivors, suggesting that intensive care does not excessively prolong the dying process. We conclude that many life-threatening complications of cancer are potentially reversible. The extent of functional recovery of survivors warrants aggressive intensive support in this setting.

Clinical characteristics of respiratory syncytial virus infections in healthy versus previously compromised host.

In an effort to delineate the clinical characteristics of respiratory syncytial virus (RSV) infection in the compromised host, we compared children with bronchopulmonary dysplasia (BPD), congenital heart disease (CHD), premature birth, failure to thrive, and gastroesophageal reflux to previously healthy children. During a four-year period, 262 patients were admitted to the hospital with RSV infection diagnosed by a rapid RSV antigen detection test. Children with BPD or CHD had more hospital days and supplemental oxygen days than the previously healthy group (P less than 0.05). Patients with BPD also had more ICU days, ventilator days, and NPO days, as well as a higher physiologic stability index and therapeutic intervention score than the previously healthy group (P less than 0.05). Premature infants were more likely to present with apnea from RSV (P less than 0.001). Patients with underlying illness tended to be older, although significant difference was demonstrated only for the BPD group (7.0 +/- 5.3 vs. 3.5 +/- 3.3, P less than 0.05). Patients with BPD and CHD had more nosocomial infections than the previously healthy group (P less than 0.0001) and death occurred only in patients with underlying illness. We conclude that previously compromised patients are at risk for more severe and prolonged RSV disease. Earlier diagnosis and therapeutic intervention may be necessary in such patients to improve outcome.

Intracranial pressure and cerebral perfusion pressure in near-drowning.

Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were strictly controlled in 11 pediatric victims of near-drowning. Three outcome groups were defined: complete recovery, persistent vegetative state, and death. In the early postimmersion phase (first 72 h), CPP was consistently above 50 mm Hg in all patients. There were occasional, nonrepetitive, and easily controllable ICP spikes above 15 mm Hg in three patients from each group. Repeated ICP spikes above 15 mm Hg were observed in some patients with adverse outcome only after 72 h. Successful control of ICP and CPP did not ensure intact survival, and sustained late intracranial hypertension is more likely a sign of profound neurologic insult rather than its cause.

Metabolism and pharmacokinetics of acetaminophen in a severely poisoned young child.

A 1-year-old child with severe acetaminophen (APAP) poisoning after ingestion of 10 gm APAP demonstrated central nervous system depression, shock, hypothermia, and metabolic acidosis. There was dramatic improvement during treatment with intravenously administered N-acetylcysteine (NAC) and hemodialysis, and the patient recovered without sequelae. A detailed study of APAP metabolism was carried out during the initial 72 hours after ingestion. APAP-sulfate and APAP-glucuronide accounted for 29% and 33%, respectively, of total drug in urine, whereas cysteine and NAC conjugates accounted for only 12%. The low incidence of severe toxicity in children after overdoses of APAP may be related to greater capacity to metabolize APAP via a nontoxic pathway.