Respiratory Care

To assess the efficacy of and patient tolerance for nasal and full-face masks during noninvasive positive-pressure ventilation (NPPV) with patients suffering acute exacerbations of chronic obstructive pulmonary disease.

A respiratory medicine ward of a referral hospital.

Fourteen patients were randomized to 2 groups. Seven used nasal masks and 7 used full-face masks. We used a portable ventilator and recorded arterial blood gases and indices of respiratory muscle effort before and after 15 min of NPPV. Patient tolerance was scored as follows: no tolerance (mask had to be withdrawn before the study period ended) = 0 points; poor tolerance (patient complained of discomfort from the ventilation devices but nevertheless remained compliant) = 1 point; fair tolerance (patient seemed uncomfortable but did not complain) = 2 points; excellent tolerance (patient felt better than before beginning NPPV) = 3 points.

The groups were comparable in clinical and pulmonary function variables at baseline. NPPV improved both arterial blood gases and the indices of respiratory effort, with no significant differences between the groups. During NPPV the group that used full-face mask had a greater decrease in respiratory rate, but no other differences. NPPV was well tolerated in both groups.

In patients suffering acute exacerbations of chronic obstructive pulmonary disease NPPV improves arterial blood gases and respiratory effort indices regardless of the type of mask used.

Nosocomial infections linked to the use of multi-dose bronchodilator nebulizer formulations have been reported in the literature.

Survey American hospital respiratory therapy services to determine practice patterns, opinions, and awareness regarding unit-dose and multi-dose bronchodilator formulations.

A quota sample targeted 4 hospital size categories (0-100 beds, 101-200 beds, 201-400 beds, and > 400 beds) using a listing of general medical/surgical hospitals from the American Hospital Association. Hospitals were contacted via telephone to identify the director of respiratory therapy services, who was invited to complete a 29-item Web-based survey of their hospital practices and their opinions about and knowledge of issues with multi-dose and unit-dose bronchodilator formulations.

One thousand forty-seven hospitals were recruited and 409 valid surveys were completed (completion rate 39%). The reported mean ± SD percentage of unit-dose nebulizer treatments was 80.2 ± 26.2%. Seventy-two percent (296) of respondents indicated having a policy and procedure manual that deals specifically with nebulized bronchodilator solutions, but only 107 reported having internal monitoring guidelines for compliance with those policies and procedures. Multi-dose bottles of bronchodilator concentrate were used with multiple patients in 77% of cases, and on average 9.7 ± 8.5 patients were treated with the same multi-dose bottle. Eighty-one percent of respondents reported that treatments from multi-dose bottles are prepared at the bedside. The length of time a multi-dose bottle was kept (after being opened) ranged from 24 hours (8%) to 1 month (11%), and only 3% of respondents reported following manufacturers' recommendations. In the respondents' opinion the chief advantage of multi-dose was cost per dose (84%), and the chief advantage of unit-dose was less risk of contamination (92%). With other factors (therapist time, cost of saline diluent for multi-dose concentrate, dose-error, and contamination) considered, 73% thought that unit-dose vials were more cost-effective. Three hundred thirty-six respondents (82%) thought that a sterile, low-volume (0.5 mL) unit-dose vial of bronchodilator concentrate would be useful, and 249 (74%) of those 336 respondents indicated that such a formulation would replace multi-dose bottles. Only 56% of respondents knew about the evidence regarding the risk of contamination with multi-dose bottles.

Multi-dose bottles of bronchodilator solution are used in approximately 20% of nebulizer treatments, and without strict adherence to infection control procedures they are a potential source of nosocomial infection. A sterile, low-volume unit-dose vial of bronchodilator concentrate would be a useful alternative to multi-dose concentrate for modifying doses or mixing drugs in nebulizer therapy.

To determine the effects of intrapulmonary percussive ventilation (IPV) on mucus clearance in tracheostomized Duchenne muscular dystrophy patients.

We studied 8 patients, 5 of whom had mucus hypersecretion (> 30 mL/d). In a randomized, cross-over study we compared assisted mucus clearance techniques with and without IPV. There were 2 treatment sequences and each patient received 5 consecutive days of each treatment sequence, delivered 3 times a day. One sequence consisted of (1) assisted mucus clearance technique (AMCT, which involves forced expiratory technique and manual assisted cough), (2) endotracheal suctioning, (3) nebulizer administration of 5 mL of 0.9% sodium chloride solution for 5 min, (4) a second AMCT session, (5) endotracheal suctioning, (6) 45 min after the end of the nebulizer treatment a third AMCT session, (7) endotracheal suctioning. The other treatment sequence was the same except that it included IPV during the 5-min nebulizer treatment. The collected secretions were weighed. Vital capacity was measured once, before the treatments. Heart rate, respiratory rate, oxyhemoglobin saturation, end-tidal carbon dioxide, airway resistance, and peak expiratory flow were measured before and at 45 min after the treatments. Mean values were compared using analysis of variance with repeated measures.

In patients with hypersecretion the mean ± SD weight of the collected secretions was significantly higher with IPV (6.53 ± 4.77 g vs 4.57 ± 3.50 g, p = 0.01). Heart rate, respiratory rate, oxyhemoglobin saturation, end-tidal carbon dioxide, airway resistance, and peak expiratory flow did not differ statistically between the 2 treatments.

IPV is a safe airway clearance method for tracheostomized Duchenne muscular dystrophy patients, and this preliminary study suggests that IPV increases the effectiveness of assisted mucus clearance techniques.

To determine the amount of albuterol, in various particle size ranges, delivered from a hydrofluoroalkane-propelled metered-dose inhaler (Airomir) in 3 models of pediatric intubation (ages 8 months, 4 years, and 16 years) using 4 types of aerosol reservoir: 3 spacers (ACE, AeroChamber HC MV, metal NebuChamber without 1-way valve) and 1 holding chamber (metal NebuChamber with 1-way valve).

Five reservoirs of each type were tested with albuterol sulfate delivered via metered-dose inhaler that delivers 100 μg of albuterol per actuation. Each reservoir was connected to an endotracheal tube (ETT) that corresponded to the given patient age (8 months = 4 French; 4 years = 5 French; 16 years = 7.5 French) and to a valved system that allowed connection of the ETT to a cascade impactor. Simulated tidal volumes representative of children of the given ages were passed through the reservoir. Both the cascade impactor and the ETT were enclosed within a 100% humidity, 37° C environment.

For the total amount of albuterol inhaled onto the impactor, and both the 1.1-4.7 μm and 1.1-3.3 μm inhaled fine-particle fractions, the NebuChamber-with-valve showed significantly greater drug delivery than the NebuChamber-without-valve, the AeroChamber HC MV, or the ACE (p < 0.001). Among the reservoirs without valves the NebuChamber showed significantly greater delivery than the AeroChamber HC MV or ACE (p < 0.001) for total drug deposition and for both the 1.1-4.7 μm and 1.1-3.3 μm fine-particle fractions. These results were consistent over all age groups. The AeroChamber HC MV had significantly greater delivery (total deposition) than the ACE (p < 0.001), except in the 4-year-old model. There were no significant differences between the AeroChamber HC MV and the ACE for either the 1.1-4.7 μm or the 1.1-3.3 μm fine-particle fraction.

An aerosol reservoir with 1-way valve positioned between the spacer and the ETT improved the amount of inhaled albuterol 300–900%, compared to the other reservoirs.