Respiratory Care

Airway reactivity is a common clinical problem in infants who require prolonged ventilator support. The decision to utilize inhaled bronchodilator therapy is frequently based on the patient's history and on the presence of intermittent wheezing and bronchospasm during examination. The response to this therapy is often difficult to quantify.

We retrospectively analyzed dynamic compliance (C_dyn) and total respiratory-system resistance (R_I [inspiratory], R_E [expiratory], R_tot [total]) by esophageal manometry and pneumotachography before (PRE) and 20 minutes after (POST) 1 actuation (90 µg) of albuterol sulfate via the endotracheal tube in 25 intubated infants (mean [SD] weight at study 1.65 [1.05] kg, mean [SD] age at study 6.6 [4.6] weeks, and mean [SD] gestational age 28 [4] weeks). These infants had been receiving mechanical ventilation and were suspected of having increased airway reactivity. Functional residual capacity (FRC) had been determined by helium dilution prior to study.

There were no significant differences between PRE and POST values of tidal volume, minute ventilation, or peak airway pressure, Cdyn, R_tot, or R_I R_E was significantly reduced POST (p < 0.05). Ten infants had a greater than 25% decrease in R_tot after albuterol, whereas 9 babies had less than a 25% decrease in R_tot. An additional 6 neonates had a greater than 25% increase in R_tot when compared to their PRE value. Tidal flow-volume-loops revealed evidence of tracheobronchomalacia (TBM) in 4 of 9 nonresponders in PRE treatment testing, and in 2 of 6 negative responders in POST-treatment testing. R was lower PRE in the negative-response group compared to the positive-response and no-response groups.

Measurement of lung function may be helpful in assessing response to bronchodilator therapy in preterm infants, and unnecessary use of this therapy can be avoided in patients who do not have a positive response. Such studies may also predict which infants will not respond to inhaled bronchodilator therapy. Increased airway reactivity may be clinically indistinguishable from fixed airway obstruction or TBM.

According to a 1992 Delphi study, 75% of respondents considered research interpretation skills important to advanced respiratory care practitioners (ARCPS). Considering that finding, we sought to describe research instruction among ARCP programs.

After several educators evaluated face validity and readability of the Research Education Questionnaire (REQ), we mailed it to ARCP programs in the U.S. listed by the Joint Review Committee on Respiratory Therapy Education (JRCRTE). The REQ contains 32 items that together describe types of programs, faculty preparation, and extent to which research instruction is offered. To follow up, we contacted 25 randomly selected nonrespondents by phone 6 weeks after the initial mailing. Descriptive statistics were generated to describe our findings.

Sixty-four percent (179/280) responded to the mailed survey. Of 25 telephone contacts, only 6 were available to survey. Of respondents, 16% offer formal courses in research. The most common goals were for students to read and interpret research and statistics. The modal reason for excluding formal research instruction was insufficient time. Of programs without research courses, 69% include journal studies. Of respondents, 72% require students to read research, 26% provide a format to evaluate it.

Formal research courses are largely restricted to BS programs (21/28). Both associate- and baccalaureate-degree programs generally require students to read research and teach them to interpret it. Although our inability to adequately characterize nonrespondents inhibits our ability to validate our sample and, therefore, its responses, the relatively high response rate (64%) lends credence to our results. We believe this research accurately describes the extent to which research concepts are taught in ARCPs and may help guide the development of future guidelines for respiratory care educational programs.

This study examined the effects of oxygen (O₂) delivery methods and ventilator settings on the fraction of oxygen delivered (FDO₂) with a portable volume ventilator. DEVICE DESCRIPTION: The Aequitron Medical LP6 is microprocessor-controlled but without an accumulator to provide supplemental O₂. METHODS AND MATERIALS: O₂ at 0.5, 1.0, and 2.0 L/min was (1) bled into the circuit distal to the bacteria filter (B), (2) entrained into the air-inlet filter using an 02 adapter (A), (3) entrained into the air-inlet filter using an O₂ adapter with a reservoir (AR), and (4) provided by the manufacturer's O₂-enrichment kit (EK). FDO₂ was measured with a calibrated O₂ analyzer and recorded at ventilator rates of 10, 12, and 14 cycles/min with 0.5- and 1.0-L tidal volumes (VTs). Multi-way analysis of variance and Fisher's post-hoc test were used to compare FDO₂S among methods.

Over all ventilator rate-Vr combinations and O₂ flowrates, the mean (SD) FDO₂ and low-high ranges were B = 33.5 (6.57)%, 25-48%; A = 26.0 (2.25)%, 23-30%; AR = 31.6 (4.82)%, 25-40%; and EK = 33.6 (7.86), 22-53%. Method B produced the most inconsistent FDO₂ and increased Vr (up to 25%) and peak-inspiratory pressure. These variations were not observed with any of the other methods. For all methods at all settings and O₂ flows, FDO₂ decreased as VT increased but not as rate increased. Difference in FDO₂ among the 4 O₂ enrichment applications was significant (p < 0.005).

Methods AR and EK provide higher and more consistent FDO₂S with less effect on Vr and peak pressure than other methods tested. However, when supplemental oxygen is administered by any of these methods, intermittent O₂ and minute ventilation monitoring is necessary.