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Biomedical subjects

J B Fink

Publications and source records attributed to J B Fink.

24 records · Page 2Linked to original sources
PubMed1996

Aerosol delivery from a metered-dose inhaler during mechanical ventilation. An in vitro model.

Successful bronchodilator therapy with a metered-dose inhaler (MDI) in intubated, mechanically ventilated patients requires adequate delivery of aerosol to the lower respiratory tract. We determined the effect of ventilator mode, inspiratory flow pattern, humidity, and spontaneous respiratory effort on albuterol delivery in a model of the trachea and bronchi. The model was ventilated through an endotracheal tube during controlled mechanical ventilation (CMV), assist control (AC), pressure support (PS), and continuous positive airway pressure (CPAP), separately with a dry and humidified ventilator circuit. Delivery of albuterol administered by a MDI and spacer on filter placed at the ends of the bronchi was measured by spectrophotometry (246 nm). Under dry conditions and with a frequency of 10 breaths/min, albuterol delivery with CMV (VT, 800 ml; 30.3 +/- 3.4%), AC (VT, 800 ml; 31.9 +/- 1.3%), PS 10 cm H2O (VT, 700 ml; 28.8 +/- 4.5%), or PS 20 cm H2O (VT, 800 ml; 30.9 +/- 1.8%) was lower than that observed with simulated spontaneous breaths with CPAP (VT, 800 ml; 39.2 +/- 1.4%) (p < 0.01 for all modes). Delivery was greater under dry (28.8 to 39%) than under humidified conditions (15.9 to 20.2%) (p < 0.005 in all modes). Albuterol delivery showed a linear correlation with both inspiratory time and duty cycle (r > 0.91). Lower respiratory tract delivery of aerosol from a MDI varied from 4.9 to 39.2%. We conclude that in addition to other known factors such as dose, type of spacer, and its position the technique of administering MDIs in mechanically ventilated patients markedly influences lower respiratory tract aerosol delivery.

Aerosols↗
PubMed1996

Dose-response to bronchodilator delivered by metered-dose inhaler in ventilator-supported patients.

In nonintubated patients, metered-dose inhalers (MDIs) are accepted as the most convenient, efficient, and cost effective method of administering inhaled bronchodilators. Recent studies have demonstrated the efficacy of MDIs in ventilator-supported patients; however, the optimal dose of a bronchodilator from a MDI is unknown. We determined the response to increasing doses of albuterol administered by a MDI and cylindrical spacer to 12 mechanically ventilated patients with chronic obstructive pulmonary disease (COPD). Four, eight, and 16 puffs of albuterol were given at 15-min intervals. Rapid airway occlusion were performed before and at 5-min intervals after albuterol for 80 min. Respiratory mechanics were also measured for 60 min in another group of seven patients with COPD who received four puffs of albuterol. Significant decrease in airways resistance occurred after administration of albuterol (p < 0.001). The decrease in airway resistance with four puffs of albuterol was comparable to that observed with cumulative doses of 12 puffs (p = 0.12) and 28 puffs (p = 0.25). Heart rate increased significantly (p < 0.01) after a cumulative dose of 28 puffs. The decrease in airway resistance was sustained for 60 min in the group that received only four puffs of albuterol (p < 0.003). In conclusion, four puffs of albuterol given by a MDI and spacer provided the best combination of bronchodilator effect and safety in stable mechanically ventilated patients with COPD.

Administration, Inhalation↗
PubMed1996

Serum albuterol levels in mechanically ventilated patients and healthy subjects after metered-dose inhaler administration.

In mechanically ventilated patients, systemic blood levels of inhaled drugs reflect absorption from the lower respiratory tract alone since, unlike nonintubated patients, oropharyngeal and gastrointestinal absorption cannot occur. To determine the efficiency of aerosol administration by a metered-dose inhaler (MDI), we measured serum albuterol levels after administration by a MDI and spacer to nine mechanically ventilated patients (10 puffs) and to 10 healthy subjects (six puffs). Serum albuterol levels (+/- SEM) quantitated by high-performance liquid chromatography and electrochemical detection were: 0.09 +/- 0.04 mg/ml/puff at baseline, 0.66 +/- 0.10 at 5 min, 0.98 +/- 0.10 at 10 min, 0.56 +/- 0.08 at 15 min, and 0.37 +/- 0.03 at 30 min in mechanically ventilated patients versus zero at baseline, 0.89 +/- 0.12 at 5 min, 1.27 +/- 0.13 at 10 min, 0.84 +/- 0.09 at 15 min, and 0.53 +/- 0.07 at 30 min in control subjects (p > or = 0.07 at 5, 10, and 30 min; p < or = 0.05 at baseline and at 15 min). Area under the curve (AUC0-30) in the mechanically ventilated patients was 16.8 +/- 1.4 versus 23.4 +/- 1.9 ng/ml/puff x min in control subjects (p = 0.014). In summary, administration of albuterol with a MDI achieved a profile of serum levels in mechanically ventilated patients similar to that in healthy control subjects, but the peak serum level and systemic bioavailability (AUC0-30) were lower in the patients. In conclusion, serum levels reliably assess lower respiratory tract deposition of albuterol, and show that MDIs are more efficient for aerosol delivery in mechanically ventilated patients than was previously reported in studies using radiolabeled aerosols.

Aged↗
PubMed1995

Comparative trial of continuous nebulization versus metered-dose inhaler in the treatment of acute bronchospasm.

STUDY OBJECTIVE: To compare continuous nebulization with the use of a metered-dose inhaler (MDI) with spacer device for delivery of albuterol in acute bronchospastic episodes in the emergency department. DESIGN: Prospective, randomized, double-blinded, placebo-controlled clinical trial. SETTING: Urban ED with a 28,000 annual census. PARTICIPANTS: Patients older than 18 years of age presenting to the ED with an acute bronchospastic episode. INTERVENTION: After conducting evaluation and collecting baseline data, we treated each patient with a continuous-flow nebulizer set to deliver 15 mg/hour of albuterol or a placebo by face mask. Subsequently, each patient received four puffs (albuterol or placebo) from an MDI with a spacer device. The four MDI puffs were followed by 5 minutes on nebulization, and this sequence was continued until predetermined therapeutic end points were reached or side effects developed. The optimal MDI dose was then determined and repeated each hour for the 3-hour time period of the study. RESULTS: Repeated-measures ANOVA testing revealed statistically and clinically significant improvements over time within each treatment group in peak flow (F = 3.864, P = .0057), Borg score (F = 14.77, P = .0001), pulse (F = 9.642, P = .0001), and respiratory rate (F = 3.081, P = .0093). However, no significant differences could be detected between treatment groups over time except for systolic blood pressure (F = 8.231, P = .0141), and this change was not considered clinically significant. CONCLUSION: On the basis of the findings of this study, we conclude that continuous nebulization is equally effective as MDI with spacer device for delivery of albuterol to treat acute bronchospastic episodes in the ED. Each method of delivery offers advantages. Each ED should decide which modality to use on the basis of its own resources.

Acute Disease↗
PubMed1986

Helium-oxygen gas therapy. Use and availability for the emergency treatment of inoperable airway obstruction.

Inoperable obstruction of the upper airway due to extrinsic malignancy may present as respiratory failure. We treated such a patient for 48 hours with 80 percent: 20 percent helium-oxygen delivered by a nonrebreathing mask while chemotherapy and radiation therapy reduced the tumor size. The need for intubation, mechanical ventilation, and high risk surgical intervention was avoided through the use of this gas therapy. We then surveyed San Francisco Bay area hospitals and found that fewer than one half could provide this potentially lifesaving gas therapy in an emergency situation. Physiologic basis of helium-oxygen gas therapy is reviewed and recommendations made for its use and availability.

Adolescent↗