RESUMEN
Nine consecutive end-stage patients with cystic fibrosis (CF) awaiting lung transplantation were admitted to the pediatric intensive care unit (PICU) in respiratory decompensation. They all received noninvasive bilevel positive airway pressure (BIPAP) support and were evaluated to determine whether or not it improved their oxygenation and provided them with long-term respiratory stability. BIPAP was applied to all patients after a brief period of assessment of their respiratory status. Inspiratory and expiratory positive airway pressures (IPAP, EPAP) were initially set at 8 and 4 cm H2O respectively. IPAP was increased by increments of 2 cm H2O and EPAP was increased by 1 cm H2O increments until respiratory comfort was achieved and substantiated by noninvasive monitoring. Patients were observed in the PICU for 48 to 72 hours and then discharged to home with instructions to apply BIPAP during night sleep and whenever subjectively required. Regular follow-up visits were scheduled through the hospital-based CF clinic. The patients' final IPAP and EPAP settings ranged from 14 to 18 cm H2O and 4 to 8 cm H2O, respectively. All nine patients showed a marked improvement in their respiratory status with nocturnal use of BIPAP at the time of discharge from the PICU. Their oxygen requirement dropped from a mean of 4.6 +/- 1.1 L/min to 2.3 +/- 1.5 L/min (P < 0.05). Their mean respiratory rate decreased from 34 +/- 4 to 28 +/- 5 breaths per minute (P < 0.05). The oxygen saturation of hemoglobin measured by pulse oximetry, significantly increased from a mean of 80% +/- 15% to 91% +/- 5% (P < 0.05). The patients have been followed up for a period of 2 to 43 months and have all tolerated the use of home nocturnal BIPAP without any reported discomfort. Six patients underwent successful lung transplantation after having utilized nocturnal BIPAP for 2, 6, 14, 15, 26, and 43 months, respectively. Three patients have utilized home BIPAP support for 2, 3, and 19 months, respectively, and continue to await lung transplantation. An acute development of refractory respiratory failure resulted in the demise of the remaining three patients after having utilized BIPAP for 3, 6, and 10 months, respectively. The authors conclude that BIPAP therapy improves the respiratory status of decompensating end-stage CF patients. It is well tolerated for long-term home use and provides an extended period of respiratory comfort and stability for CF patients awaiting lung transplantation.
Asunto(s)
Fibrosis Quística/fisiopatología , Trasplante de Pulmón , Respiración con Presión Positiva/métodos , Insuficiencia Respiratoria/terapia , Adulto , Fibrosis Quística/complicaciones , Fibrosis Quística/cirugía , Femenino , Humanos , Masculino , Insuficiencia Respiratoria/etiología , Listas de EsperaRESUMEN
PURPOSE: The purpose of this study was to investigate the effects of various intravenous anesthetics on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in two models of brain edema in a prospective study in a Pediatric critical care animal laboratory in a university hospital. MATERIALS AND METHODS: Intraparenchymal ICP monitors were inserted in 30 anesthetized adult cats. In 15 cats, an intraparenchymal balloon-tipped catheter was placed and inflated to create a space-occupying lesion (SOL) to mimic vasogenic brain edema (VBE). In the other 15 cats, cytotoxic brain edema (CBE) was created by an acute reduction in blood osmolality. We used continuous hemodiafiltration (CAVH-D) and replaced the ultrafiltrate with hypotonic solution to maintain euvolemia. At predetermined points, each cat in each model received multiple intravenous (i.v.) injections of one of the following medications: methohexital 1.5 mg/kg, propofol 2 mg/kg, or ketamine 2 mg/kg. ICP and mean arterial pressure (MAP) were continuously monitored in all animals. RESULTS: In the SOL model, all three anesthetic agents decreased ICP after each administration (P < .05). Ketamine administration also resulted in an increase in CPP in this model (P < .05). In the CBE model, none of these agents resulted in a significant change in either ICP or CPP. CONCLUSIONS: Our results indicate that i.v. anesthetics decrease ICP caused by SOL but have no significant effect on ICP due to CBE. We postulate that in the SOL model, and similarly in VBE, some brain tissue is viable and remains responsive to anesthetics. In contrast, in the CBE model, diffuse intracellular damage occurs, the cerebral metabolic rate may be severely depressed, autoregulation of the cerebral vasculature may be impaired, and unresponsiveness to i.v. anesthetics may occur.
Asunto(s)
Anestésicos Intravenosos/farmacología , Edema Encefálico/fisiopatología , Circulación Cerebrovascular/efectos de los fármacos , Presión Intracraneal/efectos de los fármacos , Análisis de Varianza , Animales , Presión Sanguínea/efectos de los fármacos , Edema Encefálico/tratamiento farmacológico , Gatos , Modelos Animales de Enfermedad , Ketamina/farmacología , Metohexital/farmacología , Monitoreo Fisiológico , Propofol/farmacología , Estudios ProspectivosRESUMEN
OBJECTIVES: To develop a simple method in an animal model to achieve deliberate hypercapnia, which can be used easily and safely to regulate the pulmonary vascular resistance without changing mean airway pressure and compromising oxygenation. DESIGN: Prospective study, with each animal used as its own control. SUBJECTS: Minipigs, weighing 11 to 14 kg (n = 7). INTERVENTIONS: A quadrilumen thermodilution pulmonary artery catheter was placed in minipigs via the internal jugular vein. Systemic blood pressure was measured with use of a femoral arterial catheter. The animals' lungs were ventilated with an FIO2 of 1.0, and a stable state of eucapnia was achieved and maintained for 30 mins. The artificial deadspace was increased every 30 mins, by connecting 45-mL (3- to 4-mL/kg) corrugated tube segments until a total deadspace volume of 180 mL was added. MEASUREMENTS AND MAIN RESULTS: Hemodynamic performance was evaluated at baseline and after 45 mL (3 to 4 mL/kg), 90 mL (6 to 8 mL/kg), 135 mL (9 to 11 mL/kg), and 180 mL (12 to 15 mL/kg) of added deadspace. Data were indexed to the animal's weight (in kg). Increased artificial deadspace produced a significant (p < .05) increase in PaCO2. These increases in PaCO2 were associated with significant (p < .05) increases of 23%, 32%, 45%, and 46% in the mean pulmonary vascular resistance values, and 6%, 16%, 23%, and 23% in the mean pulmonary arterial pressure, respectively. The systemic pH was decreased from a mean baseline value of 7.45 to 7.39, 7.28, 7.20, and 7.11, respectively. There were no significant changes in PaO2, oxygen consumption, systemic vascular resistance, and cardiac output throughout the experiments. CONCLUSIONS: A gradual increase in artificial deadspace ventilation produces a state of deliberate hypercapnia. In our animal model, a moderate increase in artificial deadspace significantly increased the pulmonary vascular resistance but was not associated with detrimental respiratory acidemia. Larger volumes of added artificial deadspace had no detrimental effect on cardiac output, oxygen content, oxygen consumption, and systemic vascular resistance, but were associated with significant respiratory acidemia and therefore should be avoided.
Asunto(s)
Hipercapnia , Circulación Pulmonar , Respiración Artificial , Espacio Muerto Respiratorio , Resistencia Vascular , Acidosis Respiratoria , Animales , Modelos Animales de Enfermedad , Hemodinámica , Estudios Prospectivos , Pruebas de Función Respiratoria , Porcinos , Porcinos EnanosRESUMEN
We devised a diagnosis and management algorithm for acute onset of central diabetes insipidus (CDI), and conducted a retrospective evaluation of its efficacy. Fourteen patients admitted to our pediatric intensive care unit (PICU) over a three year period were diagnosed with acute CDI secondary to various brain injuries. All patients were treated as per the algorithm guidelines. The initial dose of aqueous vasopressin ranged from 0.25 to 1.0 mU/kg/h. Low sodium content solution (0-0.5 normal saline) was used to replace urine output in excess of 3 ml/kg/h and for maintenance fluid therapy. The therapeutic goals included: urine output 2-3 ml/kg/h, urine specific gravity 1.010-1.020 and serum sodium 140-145 mEq/l. The pitressin dose was adjusted as deemed necessary to achieve the aforementioned goals. Our results indicate that urine specific gravity is the most sensitive parameter to respond to treatment. It was the best determinant of the adequacy of pitressin dose as it had the best linear correlation with it (r = 0.96; p = 0.009). Urine output was second best (r = 0.93; p = 0.02), whereas no linear correlation was established between pitressin dose and serum sodium concentration, nor with serum osmolality. We conclude that the algorithm developed and used by us for the management of CDI is generally efficacious. Changes in urine specific gravity follow changes in pitressin dose very closely and thus should be used as the primary parameter for determination of intravenous pitressin dose adjustment.
Asunto(s)
Algoritmos , Enfermedad Crítica , Diabetes Insípida , Vasopresinas/uso terapéutico , Enfermedad Aguda , Adolescente , Adulto , Muerte Encefálica , Niño , Preescolar , Diabetes Insípida/diagnóstico , Diabetes Insípida/terapia , Diabetes Insípida/orina , Femenino , Humanos , Lactante , Recién Nacido , Infusiones Intravenosas , Masculino , Concentración Osmolar , Sodio/sangre , Sodio/metabolismo , Resultado del Tratamiento , Urinálisis , Vasopresinas/administración & dosificación , Vasopresinas/efectos adversosRESUMEN
BACKGROUND: The usefulness of spiral computed tomographic (CT) scans of the chest with three dimensional imaging (3D-CT) of intrathoracic structures in the diagnosis and management of paediatric intrathoracic airway obstruction was assessed. METHODS: A retrospective review was made of five consecutive cases (age range six months to four years) admitted to the paediatric intensive care unit and paediatric radiology division of a tertiary care children's hospital with severe respiratory decompensation suspected of being caused by intrathoracic large airway obstruction. Under adequate sedation, the patients underwent high speed spiral CT scanning of the thorax. Non-ionic contrast solution was injected in two patients to demonstrate the anatomical relationship between the airway and the intrathoracic large vessels. Using computer software, three-dimensional images of intrathoracic structures were then reconstructed by the radiologist. RESULTS: In all five patients the imaging results were useful in directing the physician to the correct diagnosis and appropriate management. In one patient, who had undergone repair of tetralogy of Fallot with absent pulmonary valve, the 3D-CT image showed bilateral disruptions in the integrity of the tracheobronchial tree due to compression by a dilated pulmonary artery. This patient underwent pulmonary artery aneurysmorrhaphy and required continued home mechanical ventilation via tracheostomy. In three other patients with symptoms of lower airway obstruction the 3D-CT images showed significant stenosis in segments of the tracheobronchial tree in two of them, and subsequent bronchoscopy established a diagnosis of segmental bronchomalacia. These two patients required mechanical ventilation and distending pressure to relieve their bronchospasm. In another patient who had undergone surgical repair of intrathoracic tracheal stenosis three years prior to admission the 3D-CT scan ruled out restenosis as the reason for her acute respiratory decompensation. CONCLUSIONS: 3D-CT scanning is a useful additional diagnostic tool for intrathoracic airway obstruction in paediatric patients.
Asunto(s)
Enfermedades Pulmonares Obstructivas/diagnóstico por imagen , Enfermedades Bronquiales/diagnóstico , Preescolar , Constricción Patológica/diagnóstico , Humanos , Procesamiento de Imagen Asistido por Computador , Lactante , Enfermedades Pulmonares Obstructivas/cirugía , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Estenosis Traqueal/diagnósticoRESUMEN
OBJECTIVE: To determine whether ketamine infusion to mechanically ventilated children with refractory bronchospasm is beneficial. DESIGN: Retrospective chart review. SETTING: Pediatric intensive care unit (PICU) of a children's hospital. PATIENTS: Seventeen patients, ages ranging from 5 months to 17 years (mean 6 +/- 5.7 years), were admitted to our PICU over a 3-year period and received ketamine infusion during a course of mechanical ventilation. The patients had acute respiratory failure associated with severe bronchospasm due to status asthmaticus (n = 11), bronchiolitis caused by respiratory syncytial virus (n = 4), and bacterial pneumonia (n = 2). INTERVENTIONS: All patients had been mechanically ventilated for 1-5 days (2.2 +/- 1.5 days) and received conventional treatment to relieve bronchospasm for more than 24 h prior to the initiation of ketamine treatment. An intravenous bolus of ketamine of 2 mg/kg, followed by continuous infusions of 20-60 micrograms/kg per minute (32 +/- 10 micrograms/kg per minute) was administered to all patients without changing their preexisting bronchodilatory regimen. Benzodiazepines were also given intravenously to all patients during the ketamine treatment. MEASUREMENTS AND MAIN RESULTS: The PaO2/FIO2 ratio in all patients (n = 17) and the dynamic compliance in the volume-preset mechanically ventilated patients (n = 12) were calculated. The PaO2/FIO2 ratio increased significantly from 116 +/- 55 before ketamine, to 174 +/- 82, 269 +/- 151, and 248 +/- 124 at 1, 8, and 24 h respectively, after the initiation of the ketamine infusion (p < 0.0001). Dynamic compliance increased from 5.78 +/- 2.8 cm3/cmH2O to 7.05 +/- 3.39, 7.29 +/- 3.37, and 8.58 +/- 3.69, respectively (p < 0.0001). PaCO2 and peak inspiratory pressure followed a similar trend of improvement with ketamine administration. The mean duration of the ketamine infusion was 40 +/- 31 h. One patient required glycopyrrolate 0.4 mg/day to control excessive airway secretions and one patient required an additional dose of diazepam to control hallucinations while emerging from ketamine. All patients were successfully weaned from mechanical ventilation and discharged from the PICU. CONCLUSION: Continuous infusion of ketamine to mechanically ventilated patients with refractory bronchospasm significantly improves gas exchange and dynamic compliance of the chest.
Asunto(s)
Anestésicos Disociativos/uso terapéutico , Espasmo Bronquial/tratamiento farmacológico , Espasmo Bronquial/etiología , Ketamina/uso terapéutico , Respiración Artificial/efectos adversos , Adolescente , Niño , Preescolar , Monitoreo de Drogas , Humanos , Lactante , Infusiones Intravenosas , Rendimiento Pulmonar/efectos de los fármacos , Intercambio Gaseoso Pulmonar/efectos de los fármacos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
OBJECTIVE: To determine whether intravenous mannitol administration reduces intracranial pressure (ICP) in a cat model of brain edema by changing serum osmolality. DESIGN: Prospective, controlled study. SETTING: Pediatric intensive care unit laboratory in a university hospital. INTERVENTIONS: Intraparenchymal ICP monitors were placed in 12 adult cats which subsequently underwent 60 min of continuous arteriovenous hemofiltration with countercurrent dialysis (CAVH-D), using sterile water with potassium chloride as a dialysate. The ultrafiltrate was replaced with a hypotonic solution causing a rapid reduction in serum osmolality while maintaining a euvolemic state. In six cats (control group) no further interventions were instituted, while in the six other cats (mannitol group) 1g/kg mannitol was administered intravenously immediately after CAVH-D had been discontinued. ICP was monitored continuously, and serum osmolality was determined at 15-min intervals during CAVH-D and for 30 min thereafter. RESULTS: ICP increased significantly in both the control and mannitol groups during 60 min of CAVH-D. After CAVH-D, ICP was reduced in the mannitol group while ICP remained significantly higher in the control group. An inverse linear correlation was demonstrated between serum osmolality and ICP values in the control group throughout the experiment, as well as during the first 60 min in the mannitol group. However, no such correlation existed in the mannitol group after mannitol administration, as no significant changes in serum osmolality were observed while a marked reduction in ICP values occurred. CONCLUSION: Mannitol is effective in reducing increased ICP in this model of euvolemic brain edema. However, 15 min after mannitol administration, no relationship between a continued decrease in ICP and a change in serum osmolality could be established. We postulate that the beneficial effect on ICP by mannitol outlasts its possible instantaneous and short-lived effect on serum osmolality.
Asunto(s)
Edema Encefálico/tratamiento farmacológico , Diuréticos Osmóticos/uso terapéutico , Presión Intracraneal/efectos de los fármacos , Manitol/uso terapéutico , Animales , Edema Encefálico/sangre , Edema Encefálico/fisiopatología , Gatos , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Monitoreo de Drogas , Hemodiafiltración , Infusiones Intravenosas , Modelos Lineales , Concentración Osmolar , Factores de TiempoRESUMEN
OBJECTIVE: To test the hypothesis that the rate of degradation of exogenously administered albumin is faster with bolus administration than with continuous infusion and thus that a bolus administration is less efficacious in restoring blood albumin concentration (BAC) in the hypoalbuminemic critically ill pediatric patient. DESIGN: A prospective, controlled study of two groups of patients. SETTING: Pediatric intensive care unit (PICU) of a children's hospital. PATIENTS: 37 critically ill hypoalbuminemic patients (BAC < or = 2.8 g/dl), in whom no overt protein-losing disease was identified, were divided into two treatment groups and included in a 60-h study. INTERVENTIONS: 18 patients were given an i.v. bolus of 1 g/kg of 25% albumin over 4 h. This treatment was repeated after 24 and 48 h. Nineteen other patients were given the same dose of 1 g/kg of 25% albumin as a continuous 24-h infusion throughout the 60-h study period. BAC along with sodium, potassium, and total and ionized calcium were measured in the serum of blood samples obtained at predetermined intervals. MEASUREMENTS AND MAIN RESULTS: A 4 h bolus of albumin resulted in an acute rise in BAC, which declined to baseline within 24 h. A continuous infusion resulted in a steady rise in BAC with 24-h levels significantly higher than baseline. The percent change in mean BAC from baseline, calculated at 12-h intervals during the 60-h study period, showed a steady increase in the continuous infusion group with a 34% increase after the first 24 h. In contrast, the 4-h bolus method resulted in major fluctuations in the BAC values with only a 14% increase (p < 0.05) after 24 h. Albumin's volume of distribution, half-life and elimination constant, calculated based on blood albumin values during the first 24 h after the bolus administration, were 0.12 +/- 0.03 l/kg, 4.6 +/- 1.8 h and 0.17 +/- 0.06 h-1, respectively. This half-life did not apply to the continuous infusion group as a steady state was not achieved after 30 h (6 half-lives), and BAC continued to rise throughout the 60-h study period. No significant changes in blood electrolytes were observed with either method. CONCLUSIONS: The half-life of exogenous albumin in the critically ill hypoalbuminemic pediatric patient is short if given as a bolus. Continuous infusion therapy appears to be more efficacious in increasing BAC over time, as the half-life with this method appears to be longer.
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Albúminas/administración & dosificación , Albúmina Sérica/deficiencia , Adolescente , Albúminas/farmacocinética , Niño , Preescolar , Enfermedad Crítica , Monitoreo de Drogas , Humanos , Lactante , Infusiones Intravenosas , Inyecciones Intravenosas , Tasa de Depuración Metabólica , Estudios Prospectivos , Albúmina Sérica/análisis , Factores de Tiempo , Distribución TisularRESUMEN
We evaluated the needle-wire-dilator (NWD) technique, using commercially available sets, for insertion of chest tubes in 24 pediatric patients who were admitted to our pediatric intensive care unit (PICU). Fourteen patients had pneumothoraces, three had hemothoraces, two had pneumonia with empyema, four had pleural transudate effusions, and one had chylothorax. The ages of the patients ranged from four months to 24 years, and the sizes of the inserted chest tubes ranged from 10F to 20F. All insertions were successful, and the time from invasion of the pleural space by the needle to completion of chest tube insertion and connection to the tubing drainage system ranged from four to seven minutes. In four patients the procedure had to be performed while a significant coagulopathy existed. However, none of the 24 patients developed hemorrhagic complications. The only complication observed was a kink in the chest tube in five patients, resulting in recurrence of pneumothorax in four and pleural effusion in one. These adverse occurrences were corrected by repositioning the chest tubes in three patients, and by replacing the chest tubes with the stiffer, trochar type, chest tubes in the other two. We conclude that the NWD technique for chest tube insertion is quick, safe, and easy to perform in all pediatric age groups. The commercially available chest tubes used in our study were somewhat softer than the trochar type chest tubes available, which explains the occurrence of kinks in some of them.
Asunto(s)
Tubos Torácicos , Enfermedades Pleurales/terapia , Toracostomía/métodos , Adolescente , Adulto , Niño , Preescolar , Humanos , Lactante , Pediatría/instrumentación , Estudios Retrospectivos , Toracostomía/instrumentaciónRESUMEN
We describe the cardiopulmonary resuscitation efforts on five patients who presented in acute circulatory failure from myocardial dysfunction. Three patients had acute viral myocarditis, one had a carbamazepine-induced acute eosinophilic myocarditis, and one had cardiac hemosiderosis resulting in acute cardiogenic shock. All patients were continuously monitored with central venous and arterial catheters in addition to routine noninvasive monitoring. An introducer sheath, a pacemaker, and sterile pacing wires were made readily available for the patients, should the need arise to terminate resistant cardiac dysrhythmias. All patients developed cardiocirculatory arrest associated with extreme hypotension and dysrhythmias within the first 48 hours of their admission to the pediatric intensive care unit (PICU). Right ventricular pacemaker wires were inserted in all of them during cardiopulmonary resuscitation (CPR). In four patients, cardiac pacing was used, resulting in a temporary captured rhythm and restoration of their cardiac output. These patients had a second event of cardiac arrest, resulting in death, within 10 to 60 minutes. In one patient, cardiac pacing was not used, because he converted to normal sinus rhythm by electrical defibrillation within three minutes of initiating CPR. We conclude that cardiac pacing during resuscitative efforts in pediatric patients suffering from acute myocardial dysfunction may not have long-term value in and of itself; however, if temporary hemodynamic stability is achieved by this procedure, it may provide additional time needed to institute other therapeutic modalities.
Asunto(s)
Arritmias Cardíacas/terapia , Estimulación Cardíaca Artificial/métodos , Cardiomiopatías/complicaciones , Reanimación Cardiopulmonar/métodos , Paro Cardíaco/terapia , Enfermedad Aguda , Adolescente , Arritmias Cardíacas/etiología , Preescolar , Electrocardiografía , Paro Cardíaco/etiología , Ventrículos Cardíacos , Humanos , Lactante , Unidades de Cuidado Intensivo Pediátrico , Monitoreo Fisiológico/métodos , Insuficiencia del TratamientoRESUMEN
We describe seven patients who had intrathoracic airway obstruction resulting in severe respiratory distress. The patients were a four month old with bronchial cartilage hypoplasia presenting as congenital lobar emphysema; a one month old with segmental bronchomalacia; a one month old with tracheal bronchus; a two day old and a seven month old with aneurysmal distension of the pulmonary arteries secondary to tetralogy of Fallot, with absent pulmonary valve and atrioventricular canal with pulmonary poststenotic dilatation, respectively; a three year old with double aortic arch forming a vascular ring; and a three month old with tracheomalacia from tracheoesophageal fistula. The patients had various associated congenital defects, and all of them required one or more surgical procedures to repair the defects and relieve the airway obstruction. Five patients received endotracheal intubation with mechanical ventilation on their first admission, and three of them died postoperatively. The diagnostic workup to delineate the anatomic factors causing the obstruction, as well as to determine the therapeutic medical and surgical strategies to relieve it, are described. We conclude that the course of illness in most pediatric patients with intrathoracic airway obstruction is complex, is associated with high morbidity and mortality, and entails extensive multidisciplinary diagnostic and therapeutic efforts.