Biomedical subjects

M S Benson

Publications and source records attributed to M S Benson.

6 recordsLinked to original sources

PubMed1992

Interobserver variability in assessing pediatric postextubation stridor.

The reliability of parameters used to assess pediatric postextubation upper respiratory distress is unknown. We prospectively studied the interobserver reliability of six parameters commonly used to assess respiratory distress in children. Eligible patients were less than 15 years old and hospitalized for traumatic injuries at Harborview Medical Center between March and September 1989. At extubation, patients were examined independently by a physician, a nurse, and a respiratory therapist, each of whom evaluated respiratory rate (RR), stridor, air movement, flaring/retractions (F/R), level of consciousness (LOC), and oxygen saturation (O2 sat). Reliability was measured by percentage agreement and weighted kappa (Kw). The 25 children (27 extubations) had a median age of 7 years, and eight of the 27 required treatment for upper airway obstruction. Percentage agreement ranged from 82% (for air movement) to 96% (for O2 sat). Weighted kappas were excellent for RR and F/R (Kw greater than .6); moderate for LOC, stridor, and O2 sat (0.4 less than Kw less than .06); and poor for air movement (Kw less than .4). Further improvements in interobserver agreement are required to provide more consistent upper airway management in critically ill children.

Academic Medical Centers↗

PubMed1991

Predictors of postextubation stridor in pediatric trauma patients.

OBJECTIVE: To determine which factors are the best predictors of postextubation stridor in pediatric trauma patients. DESIGN: Prospective cohort study. SETTING: The Burn and Trauma ICUs at Harborview Medical Center from March to September 1989. PATIENTS: Children were eligible for the study if they were less than 15 yr old, were intubated for greater than 12 hr, and did not have underlying cardiopulmonary disease. The study included 25 patients with 30 extubations. RISK FACTORS ASSESSED: Age, type of injury (burn vs. trauma), location of intubation ("field" vs. hospital), endotracheal tube size, length of intubation, and presence of an airleak around the tube at the time of extubation at 30 cm H2O pressure. MAIN OUTCOME MEASURE: Moderate to severe postextubation stridor requiring treatment with racemic epinephrine, helium-oxygen, reintubation, or tracheostomy. RESULTS: Treatment for postextubation stridor was required after 11 (37%) of 30 extubations, with five reintubations and one tracheostomy. The best predictor of postextubation stridor was absence of an airleak at the time of extubation (sensitivity 100%, positive predictive value 79%, p less than .001), followed by type of injury (facial burn vs. all others; sensitivity 64%, positive predictive value 88%, p less than .001). After controlling for these two factors, no other factor studied was a significant predictor of postextubation stridor. CONCLUSION: In pediatric trauma patients, mechanism of injury (facial burn vs. other) and absence of an airleak at the time of extubation are the strongest factors predicting postextubation stridor. Patients with one or both risk factors require special attention to airway management.

Adolescent↗

PubMed1991

Helium-oxygen mixture in the treatment of postextubation stridor in pediatric trauma patients.

OBJECTIVE: To assess the effectiveness of a helium-oxygen mixture in reducing post-extubation stridor in children hospitalized for burns or trauma. DESIGN: Randomized, controlled crossover trial. SETTING: Harborview Medical Center's Burn and Trauma ICUs from March to September 1989. PATIENTS: Children less than 15 yr old who were electively extubated and had symptoms of postextubation stridor, but required less than or equal to 35% oxygen. INTERVENTION: Each treatment (helium-oxygen and oxygen-supplemented room air) was given in random order for 15 min after extubation. MEASUREMENTS: Respiratory distress was assessed by a physician blinded to treatment order using a standard stridor score and clinical judgment. RESULTS: There were 13 children with 15 extubations; seven (47%) of 15 patients required subsequent treatment with racemic epinephrine or reintubation. Stridor scores were lower with helium-oxygen than with oxygen-supplemented room air (2.8 vs. 3.7, p less than .005), and helium-oxygen was preferred in eight of nine trials in which one treatment was clearly favored by the physician. CONCLUSION: Because helium-oxygen therapy can reduce stridor scores and is clinically preferred by physicians caring for stridorous children, it may be a useful adjunctive therapy in pediatric trauma patients with postextubation stridor.

Adolescent↗

PubMed1989

Continuous in-line nebulizers complicate pressure support ventilation.

Patients ventilated in the pressure support mode must generate a negative airway pressure before the ventilator will deliver a breath. Inserting a continuous-flow nebulizer between the patient and the sensor in the ventilator makes it more difficult for the patient to generate this negative pressure. We observed two mechanically ventilated patients who were unable to initiate ventilator breaths in the pressure support mode while bronchodilators were being administered through a continuous-flow nebulizer. In neither case did ventilator alarms sound. Using a lung model, we found that when the nebulizer flow rate exceeded the mean inspiratory flow rate of the test lung, the negative pressure necessary to trigger the pressure support ventilator could not be generated. Critical care providers need to be aware of this potential complication, since it may lead to serious underventilation of their patients.

Administration, Inhalation↗

PubMed1987

Carbon dioxide excretion via bronchopleural fistulas in adult respiratory distress syndrome.

Expired gas and gas leaked via thoracostomy tubes was collected in nine patients with the adult respiratory distress syndrome (ARDS) and bronchopleural fistulas. Mean minute ventilation in the group was 23.9 +/- 7.5 L/min with 31 +/- 23 percent of the gas escaping via the leak. Carbon dioxide was present in the leaked gas in every patient, with the fraction of CO2 excreted via the leak highly correlated with the fraction of minute ventilation exiting via the leak (r = 0.86, p less than 0.005). Mean concentration of CO2 in leaked gas was 1.3 +/- 0.5 percent. We conclude that some of the gas leaked via a bronchopleural fistula in such patients participated in gas exchange.

Barotrauma↗

PubMed1987

Comparison of high-frequency jet ventilation with conventional mechanical ventilation for bronchopleural fistula.

In seven patients with acute respiratory failure and a bronchopleural fistula, the authors compared gas exchange and volume of gas lost via the chest tube during conventional mechanical ventilation (CV) and high-frequency jet ventilation (HFJV). After the initial comparison, patients were randomized to HFJV or CV, unless one mode of ventilation was clearly superior based on preestablished criteria. In six of the seven patients, oxygenation deteriorated after the switch from CV to HFJV. The ratio of PaCO2 to FI02 declined from 227 +/- 167 to 133 +/- 100 (mean +/- SD, P less than 0.05), and the PaCO2 increased from 47 +/- 13 to 56 +/- 18 mm Hg (P less than 0.05). The mean chest tube leak did not change significantly. Randomization of the mode of ventilation was not performed in any patient because CV was superior by a priori criteria. We conclude that when acute respiratory failure is complicated by a bronchopleural fistula, HFJV with mean airway pressures comparable to those provided during conventional ventilation does not provide satisfactory gas exchange.

Acute Disease↗