Chest
Volume 121, Issue 6, June 2002, Pages 1947-1955
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Clinical Investigations in Critical Care
Variations in the Measurement of Weaning Parameters: A Survey of Respiratory Therapists

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Objectives

Respiratory therapists differ in the methods used to obtain weaning parameters. A questionnaire survey was conducted to better characterize those differences.

Design

A questionnaire survey was conducted among respiratory therapists from nine hospitals in the Los Angeles area. The four-page, 32-question instrument was self-administered and anonymous. Responses were tabulated for analysis.

Setting

Respondents from nine hospitals, three hospitals with residency training programs and six community hospitals without training programs in the Los Angeles area.

Participants

One hundred two respiratory therapists.

Results

There was no universally acknowledged group of weaning parameters, although four parameters were named by > 90%. There was wide variation in methods used to obtaining weaning parameters. Almost all (91%) obtained measurements with the patients breathing their current fraction of inspired oxygen, but there was great variability in the ventilator mode used to collect these parameters (T-tube, continuous positive airway pressure, pressure support), with an equally wide range of pressures added to each mode (0 to 10 cm H2O). There was great variation in the time (< 1 to > 15 min) before recording weaning parameters. Measurement of parameters was done either with bedside instruments or read from the ventilator display. The maximal inspiratory pressure had great variation in the duration of airway occlusion (< 1 to 20 s), with the most frequent time frame being 2 to 4 s. Differences were noted between therapists from the same hospital as well as between hospitals.

Conclusions

There is great variation among respiratory therapists when obtaining weaning parameters. This calls for further standardization of the measurement of weaning parameters.

Section snippets

Materials and Methods

A self-administered four-page, 32-item questionnaire was developed and piloted among respiratory therapists at our institution (see Appendix). The items specifically addressed the methods by which weaning parameters were obtained, and were based on published descriptions of the techniques incorporating input from the therapists. The questionnaires were anonymous and required about 10 min to complete. Some questions allowed multiple responses, and each response was tabulated for analysis.

Nine

Results

Of a total of 166 questionnaires distributed, 102 questionnaires (61%) were completed and returned for analysis. The majority of respondents (75%) report > 5 years of experience, and over half are certified respiratory therapists. Of the 102 respondents, 46 persons (45%) work in teaching institutions. Ventilator management is primarily directed by specialty internists (pulmonary/critical care) [41%], but the therapists also receive directions from others (general internists, surgeons, specialty

Discussion

Despite several decades of use, the constellation of bedside measures collectively referred to as “weaning parameters” have never quite met expectations. Witness the large number of variables that are considered weaning parameters and the continued search for bedside measurements that more accurately predict successful discontinuation of mechanical ventilation.1,2,3,4,5,6,7,8,9,15 These physiologic markers may provide insight about a patient's ability to tolerate discontinuation of mechanical

Weaning Parameters Survey Questionnaire

  • 1.

    How many inpatient beds are in your hospital?

    • ≤ 100

    • 101 to 499

    • ≥ 500

    • Not sure

  • 2.

    How many total ICU beds are in your hospital?

    • ≤ 10

    • 11 to 24

    • 25 to 49

    • 50–99

    • ≥ 100

  • 3.

    What types of ICUs are in your hospital?

    • Medical ICU

    • Surgical ICU

    • Pediatric ICU

    • Coronary care unit

    • Combined medical-surgical ICU

    • Step-down unit with ventilators

    • Step-down unit without ventilators

    • Specialized ICU (ie, burn), please specify

  • 4.

    Does your hospital have a chronic ventilator unit (ward setting) without monitors?

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