Abstract
BACKGROUND: Respiratory therapists (RTs) play a crucial role in managing mechanically ventilated patients, such as addressing patient-ventilator asynchronies that may contribute to patient harm. Waveform analysis is integral to the evaluation of patient-ventilator asynchronies; despite this, no published studies have assessed the ability of practicing RTs to interpret ventilator waveform abnormalities.
METHODS: The study took place between June 2017–February 2019. Eighty-six RTs from 2 academic medical centers enrolled in a one-day mechanical ventilation course. The scores of 79 first-time attendees were included in the analysis. Prior to and following the course, RTs were asked to identify abnormalities on a 5-question, multiple-choice ventilator waveform exam. They were also asked to provide a self-assessment of their ventilator management skills on a 1 (complete novice) to 5 (expert) scale.
RESULTS: Initial scores were low but improved after one day of ventilator instruction (19.4 ± 17.1 vs 29.6 ± 19.0, P < .001). No significant difference was noted in mean confidence levels between the pre- and post-course assessments (3.8 ± 0.9 vs 3.8 ± 1.0, P = .56). RTs with fewer years of clinical experience (0–10 y) had a statistically significant improvement in their post-course test scores relative to their pre-course scores (0–5 y: 12.5 ± 10.1 to 46.0 ± 10.8, P < .001; 6–10 y: 18.7 ± 15.8 to 32.1 ± 16.7, P = .02), whereas those with > 11 y of clinical experience did not (11–20 y: 22.4 ± 15.5 to 27.4 ± 19.0, P = .44; 21+ y: 19.6 ± 22.1 to 15.3 ± 13.8, P = .50).
CONCLUSIONS: RTs may benefit from additional training in ventilator waveform interpretation, especially early in their clinical training. More work is needed to determine the optimal length and content of a mechanical ventilation curriculum for RTs.
Introduction
Respiratory therapists (RTs) play an integral role in the care of critically ill patients, particularly those patients requiring mechanical ventilation who are principally managed in the ICU.1 RTs work closely with physicians to oversee the management of ventilators, interpret data to make necessary ventilator adjustments, and implement ventilator-centered protocols.2 The recognition of abnormal patient-ventilator interactions that may predispose patients to harm is crucial to the management of mechanical ventilation, as is the knowledge of techniques necessary to remedy these issues. RTs who possess the knowledge and skills to troubleshoot patient-ventilator asynchronies through analysis of ventilator waveforms, recognition of signs of auto-PEEP, and interpretation of changes in peak and plateau pressures may help to prevent harm from ventilator-induced lung injury. In so doing, these providers are critical contributors to optimal care of the mechanically ventilated patient.
After receiving educational degrees in respiratory care, RTs in the United States take credentialing examinations through the National Board for Respiratory Care (NBRC),3 which in part assesses the ability of the RT to analyze ventilator waveforms. In addition to assessing the initiation, management, and troubleshooting of mechanical ventilation, the Therapist Multiple-Choice Examination and Clinical Simulation Examination include content areas such as recognizing and correcting patient-ventilator dyssynchronies, utilizing ventilator graphics, and auto-PEEP determination.4 The content outline of the adult critical care specialist, an advanced specialty credential offered by the NBRC, notably identifies waveform analyses as one of 9 key topics related to mechanical ventilation.5
Though RT credentialing exams assess waveform analysis, no published studies have assessed the ability of practicing therapists in the United States to interpret ventilator waveforms and identify significant pathology. One prior Chilean study did demonstrate improved detection of patient-ventilator asynchronies among health care professionals (including physicians, nurses, and physiotherapists) with prior training in mechanical ventilation relative to those with no prior training.6 A separate paper concluded that experienced critical care nurses who underwent 40 h of dedicated training in identifying ineffective inspiratory efforts during expiration could reliably identify these specific forms of asynchrony.7 Similarly, no prior studies have considered the confidence of therapists in their ability to manage mechanical ventilators.
Our group previously developed a 2-part, multi-institutional mechanical ventilation course for physicians, specifically first-year critical care fellows. The curriculum includes formal didactics, hands-on simulations, and small-group praxis sessions.8 As part of this course, we distributed a pre- and post-test assessment. Of a total of 100 possible points, fellows received relatively low scores on the pre-test, which significantly improved (18.0 ± 1.6 to 77.4 ± 2.4) after 5 d of dedicated ventilator instruction.9
We conducted an abridged version of the physician mechanical ventilation course for RTs and studied the performance of RTs enrolled in the course. Through our analyses, we sought to determine the relative confidence and competence of RTs in identifying ventilator waveform abnormalities.
QUICK LOOK
Current Knowledge
Prior publications have reported that physicians training in critical care as well as practicing intensivists have variable knowledge of ventilator waveform asynchronies. Though respiratory therapists (RTs) work closely with intensivists to manage mechanical ventilation in critically ill patients, little is known about the ability of practicing RTs to interpret ventilator waveforms.
What This Paper Contributes to Our Knowledge
Practicing RTs at 2 academic centers participating in a one-day mechanical ventilation workshop had improved ventilator waveform examination scores after the course compared to pre-course. Though the score improvement was statistically significant, the increase was modest and confidence scores in ability to interpret waveforms were unchanged. The subgroup of RTs early in their career appeared to derive the most benefit from the training.
Methods
Subjects
This study took place between June 2017–February 2019. During this time period, 4 separate one-day courses were held (June 2017, April 2018, October 2018, and February 2019). The courses were attended by a total of 86 therapists from 2 academically affiliated hospitals. Of the 86 therapists, 7 attended the course twice; only the initial scores from these 7 learners were included in our analysis. The therapists who participated in this study reported a broad spectrum of experience, ranging from less than one year to more than 20 years of experience as an RT (Table 1). All participating institutions provided institutional review board (IRB) exemption for this research.
Demographic Information for Course Participants
Curriculum
We adapted the multi-day fellows’ curriculum into a one-day course to make the course more conducive to a busy RT’s schedule. The structure and efficacy of the fellows’ ventilator curriculum has been described previously.9 A needs assessment for the RT course was conducted through discussions with 2 RT educators (EK, NNS), who offered feedback on existing components from the fellows’ course that would be most useful to RTs. The didactics were subsequently modified based on this feedback. Five of the authors (BWL, NS, EK, NNS, SC) reached unanimous agreement about the course content.
Each RT course was structured as a single 9-hour day. Educational content was disseminated through traditional lectures as well as interactive small-group praxis and ventilator simulation sessions (Table 2). Instructors included both physicians and RTs. The lectures reviewed such core topics as modes of ventilation, normal waveforms, and patient-ventilator asynchronies, with emphasis placed on abnormal waveform analysis. These topics were then reviewed and reinforced through small-group didactics.
Curriculum Description for the Mechanical Ventilation Course
Waveform Test
Prior to and immediately following the course, RTs completed a waveform examination. This 10-min examination was the same test that we used to assess critical care fellows during the mechanical ventilation course for fellow-level physician trainees.9 Since no set standard for assessing proficiency in mechanical ventilation exists,10 this exam was developed to assess an individual’s understanding of ventilator-based pathology that could result in significant morbidity and mortality. The exam was written by one of the senior authors with expertise in mechanical ventilation (BWL) with input from other experts in mechanical ventilation. Over several years, the questions were modified and refined based on learner and instructor feedback. After this iterative process, the current version of the exam was pilot tested by critical care fellows and RTs before being administered for the current study.
The pre- and post-course examinations included the same questions, though the order was rearranged. This exam consisted of 5 sets of waveforms depicting both pressure-time and flow-time curves, printed in color and distributed as a paper examination (see related supplementary materials at http://www.rcjournal.com). We limited the exam content to 5 waveforms so as to make the examination a practical, efficient tool for assessment embedded in a one-day workshop. The images demonstrated several pathologies discussed during the course, namely asynchronies of trigger (ineffective triggering or auto-triggering), inspiratory flow (flow starvation or flow excess), cycling (premature or delayed cycling), or expiration (auto-PEEP). Learners were provided with a set of possible answer choices (labeled A–J) detailing specific pathologies as well as some of the adverse clinical sequelae of these pathologies, including a potential for diaphragmatic fatigue or atrophy. Learners were asked to circle all descriptions that they felt applied to each image. The questions were weighted equally, with each contributing 20 possible points to a total exam score of 100 points. Three authors (MA, BWL, NS) scored all of the waveform exams. Each exam was scored twice by 2 of the authors to ensure that there were no differences in scores and to verify inter-rater reliability.
As part of the exam, RTs were also asked to report their confidence in managing a mechanical ventilator. RTs were asked to provide an honest self-assessment of their ventilator management skills on a 1–5 scale, where 1 represented a complete novice and 5 represented an expert.
Statistical Analysis
The primary outcome of interest in this study was the difference in RTs’ waveform exam scores prior to and following the mechanical ventilation course. Other outcomes studied included the difference in RTs’ confidence prior to and following the course as well as the impact of the number of years of experience as a therapist on each RT’s pre-course confidence and exam scores. Paired t tests were used to compare RT exam scores and confidence levels prior to and following the course. Linear mixed models were used to assess the effect of years of RT experience on changes in exam scores and confidence levels, accounting for repeated measures of subjects and clustering of subjects within institutions. Stata/SE 16.0 (StataCorp, College Station, Texas) and SAS version 9.4 (SAS Institute, Cary, North Carolina) were used for the statistical analyses. A 2-sided P value < .05 was considered significant.
Results
Of the 79 eligible therapists taking the course for the first time, 74 and 73 learners completed the pre- and post-tests, respectively. A subset of learners provided information regarding the number of years that they had worked as an RT, with 70% (52/74) and 64% (47/73) of RTs responding to this question on the pre- and post-course exam, respectively. There was a significant improvement in mean waveform examination scores between the pre- and post-course assessments (19.4 ± 17.1 vs 29.6 ± 19.0, P < .001) (Fig. 1). There was no statistically significant difference in mean confidence levels on the pre- and post-course assessments (3.8 ± 0.9 vs 3.8 ± 1.0, P = .56) (Fig. 2).
Waveform examination scores pre- and post-course. There was a significant improvement in mean waveform examination scores between the pre- and post-course assessments (19.4 ± 17.1 vs 29.6 ± 19.0, P < .001).
Learner confidence pre- and post-course. There was no statistically significant difference in mean confidence levels on the pre- and post-course assessments (3.8 ± 0.9 vs 3.8 ± 1.0, P = .56).
We also analyzed the impact of the number of years of RT experience on both pre-course exam scores and pre-course confidence levels. Linear mixed models revealed no significant correlation between pre-course confidence levels and years of experience (slope estimate 0.13 [0.10], P = .19). Similarly, there was no significant correlation between pre-course exam scores and years of experience (slope estimate 2.64 [2.18], P = .24).
Finally, we conducted a secondary analysis in which we considered the impact of the number of years of RT experience on post-course scores. For this analysis, RTs were stratified by years of clinical experience, ranging from 0–5 y, 6–10 y, 11–20 y, and ≥ 21 y of experience. Based on this stratification, we compared the change between pre- and post-test scores of learners and found that learners with fewer years of experience as an RT had a greater improvement in post-test scores than more experienced RTs (P < .001) (Fig. 3). RTs with 0–5 y and 6–10 y of clinical experience demonstrated a statistically significant improvement in their scores (12.5 ± 10.1 to 46.0 ± 10.8, P < .001; 18.7 ± 15.8 to 32.1 ± 16.7, P = .02, respectively). In contrast, RTs with 11–20 y and ≥ 21 y of training did not demonstrate a significant improvement in their scores (22.4 ± 15.5 to 27.4 ± 19.0, P = .44; 19.6 ± 22.1 to 15.3 ± 13.8, P = .50, respectively).
Difference between pre- and post-course test scores by years of clinical experience. The delta scores (post-test–pre-test) are shown based on years of clinical experience as an respiratory therapist.
Discussion
Despite the training that critical care RTs receive in mechanical ventilation as part of their initial credentialing and maintenance of certification, RTs’ ability to recognize patient-ventilator asynchrony as measured in our pre-course test was low. Our group’s prior work has shown that traditionally trained critical care fellows lack expertise in this area as well.9 Given the frequency with which these asynchronies occur, this finding suggests that there is a need for effective, targeted teaching in mechanical ventilation among various members of the ICU team.11
Though we had hoped that our focused, one-day, 9-h course would significantly improve RTs’ ability to interpret waveforms, the clinical relevance of this modest improvement in mean scores from 19.4 of 100 possible points (19.4% correct) to 29.6 of 100 possible points (29.6% correct) is unclear. There are several potential explanations as to why this effect was so modest. We modified our typical 5-day curriculum (the fellows’ course) to a one-day course in the hopes that this would be more conducive to a busy RT’s clinical schedule; in so doing, we condensed some discussions and eliminated other topics entirely. For example, we assumed that RTs with prior critical care training would possess knowledge of fundamental mechanical ventilation equations such as Ohm law, the equation of motion, and the natural decay equation, so we omitted lectures related to these topics. Perhaps a dedicated refresher of these topics would help to improve RTs’ performance on this specific assessment. A more streamlined course also allowed for less spaced learning and repetition, which would have been helpful to reinforce concepts related to this challenging coursework.
Interestingly, our data revealed significantly greater post-course improvement in scores among those with fewer (≤ 10) years of experience (Fig. 3). In fact, those RTs with the most clinical experience (≥ 21 y) did not have any increase in post-test score, scoring an average of 19.6 on the pre-test compared to 15.3 on the post-test (P = .50). These findings have very interesting implications for medical educators. More novice learners may be more receptive to educational curricula relative to those with more experience, who may be more “set in their ways.” These findings suggest that there may be a benefit to implementing curricular interventions early in a learner’s career.
The confidence of RTs, on average, did not significantly change from pre- to post-course. We speculate that this confidence perhaps derives from the rigorous educational and hands-on clinical training that RTs complete as part of their certification. Further analysis of RT confidence based on years of clinical experience revealed that there was a slightly higher but not a statistically significant pre-course confidence among RTs with more clinical experience. We speculate that experienced RTs, in line with their higher pre-course exam scores, may have more confidence in their abilities than those who are relatively novices.
This study has several strengths. First, the curriculum utilized to teach the RTs represented a modified form of part I of the fundamentals of mechanical ventilation curriculum used to teach fellows; this curriculum has been extensively modified and refined over the past several years through iterative design incorporating both formal and informal feedback from fellows.8 Additionally, both courses utilize a multidisciplinary educational approach, with lectures and small-group sessions led by both physicians and RT educators. We also used the same waveform examination, which has been previously validated by our group. The cohort of therapists described in this study derived from academic medical centers in different geographic areas. We believe that this variety helps to extend the generalizability of our findings. Finally, we analyzed RTs with a wide range of clinical experience, ranging from those who had recently graduated to those with nearly 30 years of experience.
The study also has several limitations. As noted, modification of the curriculum for RTs from one previously developed to teach fellows may not have been optimal, both in terms of the specific content reviewed and the duration of the course. However, it was necessary to shorten the course to enable practicing RTs to attend due to their clinical schedules. With regard to our means of assessment, whereas the ventilator waveform examination assesses learners’ abilities to identify key pathologies in ventilated patients, the exam does not reflect the range of skills needed to function as an RT. The course and examination were given to RTs at 2 academic centers, so the results may not be generalizable to RTs at other academic medical centers or RTs practicing in community settings. In addition, several RTs chose not to write in demographic information, which restricted our ability to analyze the impact of years of experience as an RT on confidence and competence. Another study limitation is that the waveform test is not an exhaustive assessment of all asynchronies in all modes of ventilation. However, the test was structured to be a practical assessment of common important asynchronies that fit into a one-day workshop. Finally, because we used the same examination (albeit with the questions reordered) for the pre- and post-test assessment, there is the possibility of test-retest bias. We mitigated this risk by ensuring that answers to the questions were not provided to learners at any point during the course and by making sure the images included on the examination were not used as examples during the course.
Conclusions
Our group has previously demonstrated that dedicated instruction in mechanical ventilation improves the performance of first-year critical care fellows in ventilator waveform analysis. That training consisted of a 3-day workshop followed by a 2-day workshop 6 months later. This study shows that after a one-day ventilator course practicing RTs had a statistically significant increase in exam scores on a test assessing waveform interpretation. Given that the mean score was still low after the course, however, therapists may benefit from additional training in both ventilator waveform analysis as well as in identifying pathology that may place patients at risk for harm or death. Further work must be done to determine the optimal methods to teach these ventilator management skills effectively as well as the optimal duration of a course.
Footnotes
- Correspondence: Megan Acho MD. E-mail: achom{at}med.umich.edu
The authors have disclosed no conflicts of interest.
Supplementary material related to this paper is available at http://www.rcjournal.com.
- Copyright © 2022 by Daedalus Enterprises