Abstract
BACKGROUND: There is currently no standardized way to determine suitability for extubation of pediatric ICU (PICU) patients, potentially resulting in prolonged duration of mechanical ventilation. We aimed to design and implement a protocol for screening all intubated PICU patients for extubation readiness.
METHODS: We adopted the quality improvement (QI) Model for Improvement with Plan-Do-Study-Act (PDSA) cycles to achieve this aim. This QI project was conducted over 11 months in a multidisciplinary PICU. Outcome measures included the (1) development of a standardized extubation readiness test (ERT) that was acceptable and safe; (2) performance of ERT on > 80% of all mechanically ventilated subjects; and (3) maintenance or reduction in mechanical ventilation duration, extubation failure (non-elective re-intubation within 48 h of extubation), and need for rescue noninvasive ventilation (NIV). Balancing measures were to ensure (1) no compromise of the subject's clinical status; and (2) acceptability of the ERT workflow by medical, nursing, and respiratory therapist (RT) teams.
RESULTS: Four PDSA cycles were necessary to achieve the aims of this study. During the QI period, 438 subjects were admitted to the PICU. The ERT was championed by the RTs who conducted the test during office hours. ERT performance increased from 0% (baseline) to 90% (fourth PDSA cycle). Extubation failure rate after implementing ERT was reduced compared to baseline (4/31 [12.9%] vs 3/127 [2.4%], P = .01), whereas need for rescue NIV (3/31 [9.7%] vs 10/127 [7.9%], P = .74) and duration of mechanical ventilation (2 [1–7] d vs 1 [1–3] d, P = .09) were unchanged. PICU length of stay was reduced after implementing ERT (5 [3–10] d vs 3 [1–6] d, P = .01). No subject was destabilized as a result of ERT, and PICU staff found the workflow acceptable.
CONCLUSIONS: An acceptable and safe ERT protocol was implemented and found to improve outcomes in PICU subjects on mechanical ventilation.
- ventilator liberation
- ventilator weaning
- spontaneous breathing trial
- mechanical ventilation
- airway extubation
- extubation failure
- respiratory therapy
Introduction
Evidence supports the use of respiratory therapist (RT)– directed protocols in respiratory care with positive impact on increased appropriate care along with reduction in health care costs and adverse events compared to physician-directed care.1–7 Current evidence and consensus guidelines recommend extubation readiness testing (ERT) in mechanically ventilated adult patients through the use of standardized weaning protocols followed by the use of a spontaneous breathing trial (SBT) prior to extubation.8–10 A reduction in duration of mechanical ventilation, weaning, and ICU length of stay is associated with the use of standardized mechanical ventilation weaning protocols and ERT/SBTs.9,10
There is, however, lack of consensus guidelines for weaning of pediatric patients from mechanical ventilation. Mechanical ventilation is routinely used in 30–50% of patients admitted to pediatric ICUs (PICUs).11–14 Approximately 30–60% of unplanned pediatric extubations are successful, suggesting that clinicians are missing earlier opportunities for extubation and that these patients are on the mechanical ventilator longer than necessary.15–20 Prolonged mechanical ventilation and weaning as well as extubation failure are associated with increased morbidity and mortality.12,14,18–21 Performing a standardized extubation readiness assessment routinely in pediatric patients may aid in identifying patients ready for extubation and potentially reduce the number of days of mechanical ventilation and ICU stay.22–25 Physician-directed weaning of mechanical ventilation lacks consistency and may result in delay in identifying patients who are ready for extubation.22,26 In contrast, wrongly identifying patients who are ready for extubation may lead to extubation failure that is associated with prolonged mechanical ventilation, longer intensive care and hospital stay, higher ventilator-associated pneumonia rates, increased hospital cost, and mortality.12,27–29
ERT consists of a series of screening criteria that identifies a patient who may tolerate extubation such as vital signs, ventilator settings and parameters, presence of endotracheal tube (ETT) cuff leak, conscious level, level of sedation, and ability of the patients to protect their airway.30–33 Once a patient passes the ERT screening, an SBT is then conducted to assess patient's respiratory drive and strength by placing them on minimal ventilatory support to simulate extubation conditions without actual removal of the ETT. In pediatric patients, SBT is most commonly done by placing patient on pressure support ventilation (PSV) with pressure support (PS) ≤ 10 cm H2O, PEEP ≤ 8 cm H2O, and FIO2 ≤ 0.4 for a duration of 2 h.22,24,26,30–34
There is currently no standardized way to determine suitability for extubation in PICU patients in our hospital, potentially resulting in longer-than-necessary mechanical ventilation. We conducted a quality improvement (QI) project primarily aiming to decrease the duration of mechanical duration by 1 d through the implementation of an RT-driven ERT protocol by 12 months.
QUICK LOOK
Current Knowledge
There is current evidence to support the use of extubation readiness test (ERT) and spontaneous breathing trials in critically ill adults to facilitate successful extubation. There is, however, limited evidence for the use of ERT in pediatric patients.
What This Paper Contributes to Our Knowledge
A quality improvement project was conducted to implement an ERT protocol in a multidisciplinary pediatric ICU (PICU). Protocol adherence was greater than 80% from the third PDSA cycle. This ERT protocol facilitated timely extubation, with a reduction in extubation failure and PICU stay without any destabilization of the subjects nor interruption in routine care.
Methods
Quality Improvement Project Design
The project protocol was reviewed and exempted from institutional review board approval as it was a QI project. We adopted the Model for Improvement QI process to achieve the aims of this study.35–37 The project took place over 11 months with a total of 4 plan-do-study-act (PDSA) cycles in a multidisciplinary PICU. Outcome measures included the (1) development of a standardized ERT that was acceptable and safe; (2) performance of ERT on > 80% of all mechanically ventilated subjects; and (3) maintenance or reduction in mechanical ventilation duration, extubation failure (non-elective re-intubation within 48 h of extubation), and need for rescue NIV. Balancing measures included (1) any compromise of the subject's clinical status; and (2) acceptability of ERT workflow for medical, nursing, and RT teams.
Setting
The PICU at KK Women's and Children's Hospital is a 16-bed tertiary-care multidisciplinary medical/surgical and cardiothoracic unit, which admits approximately 500–600 patients per year. Our unit is usually staffed with 1–2 RTs during office hours. A core group of 4 RTs routinely practices in the PICU. Due to personnel power constraint, there is no RT coverage during nights and weekends. The majority of our patients are initially ventilated with pressure control intermittent mandatory ventilation mode with the PS set at the same level or 2 cm H2O < the δ pressure. Ventilator settings are determined at the preference of the PICU attending/team with constant communication with the RT team. Prior to this initiative, ventilator management, extubation readiness assessment, the decision to proceed with extubation, and the need for postextubation respiratory support are managed at the discretion of the PICU attending/team.
Subject Population
This ERT QI initiative included all subjects who were admitted to PICU between June 2020–April 2021 and required mechanical ventilation regardless of the duration of ventilation and subject's age. This population consisted of subjects who were intubated inside and outside the hospital. We excluded from analysis patients (1) with tracheostomy tube in place prior to PICU admission and (2) those who died before extubation. For subjects with multiple mechanical ventilation courses, only the first extubation was included for analysis. Baseline data for June and July 2020 were collected for subjects admitted prior to the implementation of the ERT protocol. We applied the same inclusion and exclusion criteria to this pre-intervention cohort.
Preintervention Practice
Prior to implementation of the ERT protocol, the decision for extubation and all extubation parameters was made at the discretion of the attending physician, with no standardized assessment of readiness or workflow. Extubation readiness most often involved an SBT of placing the subject on PSV to assess their respiratory drive and strength. Regardless of ETT size, PS was usually set at 10 cm H2O, PEEP at 5–8 cm H2O, with FIO2 ≤ 0.4. The timing, frequency, duration, and pass/fail criteria for the SBT varied widely. The type of respiratory support (eg, oxygen therapy, high-flow nasal cannula, or NIV) that the subject required postextubation was also mostly unplanned. Despite being trained and experienced, RTs were not empowered to perform ERT. Input from their assessment was, however, valuable to the clinician making the decision for extubation.
Protocol Development
An RT-driven ERT protocol was developed for the management of pediatric subjects on conventional invasive mechanical ventilation. This was developed based on an extensive literature review of pediatric ventilator weaning strategies.24,26,30–33,38–42 Multidisciplinary input and consensus were obtained among stakeholders (medical, nursing, and RT) prior to implementation. The RT-driven ERT protocol consisted of an ERT screening worksheet and SBT assessment. ERT screening incorporated various clinical parameters and screening criteria such as vital signs, hemodynamic status, ventilatory parameters, and mental status prior to initiation of the SBT. Importantly, the ERT screening included an assessment of the subjects' level of sedation, ability to protect their airway (cough strength and secretion management such as suctioning frequency and amount), and presence of ETT leak (Supplemental Fig. 1, see related supplementary materials at http://www.rc.rcjournal.com). In addition and in absence of contraindications, ETT leak tests were done with different positions of the head and chin, and the lowest value was taken into account.
ERT screening was performed every morning by RTs on existing PICU subjects or on new admissions throughout the day in whom extubation was anticipated. Subjects who passed the ERT screening criteria then underwent a standardized SBT for a duration of 2 h. In the SBT, subjects were placed on PSV with their current FIO2 (max of 0.4), current PEEP level (max of 8 cm H2O), and PS level based on ETT size; PS level could then be titrated to a minimum of 5 cm H2O if the subjects tolerated their current PS level for 1 h.32,33,39,43 Despite studies demonstrating that conducting SBT with PS may overestimate extubation readiness as it underestimates effort of breathing, the decision was to use PS based on ETT size during the SBT for this QI project in order to be more aligned with our current practice while at the same time to reduce overestimation of effort of breathing.44–47
Subjects tolerated the trial if their vital signs, tidal volume, and end-tidal PaO2 were within a predetermined safe range for the duration of 2 h. Subjects who failed the SBT at any time point were returned to their previous ventilator settings prior to the SBT. Subjects who passed the SBT would have their blood gas taken and remained on the SBT ventilator settings until extubation occurred. A subject's readiness for extubation was communicated to the medical and nursing team. A set time for extubation and type of postextubation respiratory support was then planned. The final decision for extubation remained at the discretion of the attending physician.
Protocol Implementation
The implementation of the ERT protocol was championed by RTs. This QI initiative was presented to all PICU staff prior to implementation to ensure all staff was familiar with the workflow. Additionally, the ERT protocol was included in the orientation training sessions for new residents who rotated through PICU. Daily ERT screening commenced in August 2020 and occurred initially only during weekdays and office hours between 8:00 am to 5:30 pm when RTs were covering the unit. ERT screening worksheets were completed for all mechanically ventilated subjects and filed in the case notes. Compliance to the protocol was reviewed every 8 weeks; barriers to and opportunities for improved adherence were identified throughout the QI PDSA cycles and addressed by the core QI team.
A total of 4 PDSA cycles were required. Modifications made to the ERT protocol to improve compliance included adjustments to (1) sedation cutoff dosages, (2) timing of the last dose of muscle relaxant, (3) milrinone cutoff dosage, and (4) a formal handover to the on-call medical team to perform the ERT for anticipated after-hours admissions/extubations. In addition, care providers were encouraged to plan extubations shortly after passing the 2-h SBT and during office hours for subject safety. Excessive secretions and a lack of ETT cuff leak were made relative contraindications and mandated a review by the managing PICU team prior to extubation to determine if a course of anti-sialagogues or dexamethasone was indicated. Outcome of the ERT/SBT was verbally conveyed to the managing PICU team and documented in the electronic medical records.
Data Collection
Data collection was performed prospectively by the core QI team using a standardized data collection tool and included subject demographics (age, sex, weight), clinical characteristics (admission diagnosis, comorbidities), and outcomes. If a subject was intubated prior to PICU admission, PICU admission was considered the time of intubation. Extubation failure was defined as the need for non-elective re-intubation within 48 h of extubation. Rescue NIV was defined as NIV that was not planned for prior to extubation or the need to escalate respiratory support to NIV within 48 h of extubation. The cause of extubation failure and indication for rescue NIV were also noted. Balancing measures included any compromise of the subject's clinical status during the SBT and acceptability of the ERT protocol for medical and nursing teams that was determined from collected data and by surveying the staff via e-mail questionnaire.
Statistical Analysis
The outcome measures that we analyzed included > 80% ERT performed on all eligible mechanically ventilated subjects, reduction in mechanical ventilation duration and maintenance, or reduction in extubation failure and/or need for rescue NIV. Statistical comparisons were made between the (1) pre-intervention versus post intervention and (2) extubation success versus extubation failure and/or rescue NIV groups using the chi-square test and the Wilcoxon rank-sum test as appropriate. Categorical variables were presented as counts (percentages). All continuous data were not normally distributed, and hence, nonparametric statistics were used in the descriptive analysis and presented as median (interquartile range).26,31 In addition to standard statistical analysis, outcomes were analyzed in statistical process control charts. X-bar control charts were used that included the center line (mean) and upper and lower control limit (3 times SD above and below the center line, respectively) lines. The ERT adherence percentage was calculated by comparing the number of subjects who were mechanically ventilated to the number of subjects with ERT performed by RTs or physicians.
Results
A total of 438 children were admitted to the PICU during the course of this QI initiative between June 2020–April 2021. Of these, 184/438 (42.0%) required mechanical ventilation, but 158/438 (36.1%) were included for analysis after applying exclusion criteria (Table 1). Adherence to the ERT protocol improved with each successive PDSA cycles (58% after PDSA 1, 65% after PDSA 2, 81% after PDSA 3, and 90% in PDSA 4), achieving our target of ≥ 80% by PDSA 3 (Fig. 1).
Bar chart of extubation readiness tests performed over the 4 plan-do-study-act (PDSA) cycles. Dotted line shows target (80%). PDSA = plan-do-study-act; ERT = extubation readiness test; PICU = pediatric ICU.
Characteristics of Subjects Pre-Intervention and Post Intervention
There was a statistically significant reduction in PICU stay in the post-intervention arm compared to pre-intervention arm (5 [3–10] d vs 3 [1–6] d, P = .01) (Table 1). There was a reduction in duration of mechanical ventilation for the post-intervention arm visualized as a shift in the center line in Figure 2; however, this was not statistically significant. Subjects who failed extubation or required rescue NIV were shown to also have longer mechanical ventilation (3.5 [2.0–7.0] d vs 2.0 [2.0–4.0] d, P = .036) and ICU duration (7.5 [5.0–15.0] d vs 4.0 [2.0–6.0] d, P = .002) compared to those who were successfully extubated and without rescue (Supplemental Table 1, see related supplementary materials at http://www.rc.rcjournal.com).
Control chart of pre- and post-intervention duration of mechanical ventilation. Dashed line at center shows the mean. Dotted lines show the upper and lower control limits.
The extubation failure rate was reduced in the post-intervention versus pre-intervention arm (4/31 [12.9%] vs 3/127 [2.4%], P = .01). The most frequent cause of failed extubation, regardless of intervention, was cardiac compromise (5/7 [71.4%]) (Table 2). The need for rescue NIV was unchanged in the 2 arms (3/31 [9.7%] vs 10/127 [7.9%], P = .74). The two most frequent causes of requiring rescue NIV were cardiac compromise (4/11 [36.4%]) and respiratory distress (4/11 [36.4%]). Figure 3 illustrates the reduction in extubation failure and need for rescue NIV in the pre- and post-intervention arms.
Control chart of pre- and post-intervention rate of requiring re-intubation or rescue noninvasive ventilation. Dashed line at center shows the mean; dotted line shows the upper control limits. The lower control limit fell into the negative range and was thus omitted.
Indications for Re-Intubation Within 48 Hours and Rescue Noninvasive Ventilation
In terms of the balancing measures, 18 staff responded to the survey representing medical, nursing, and RT groups. All 18/18 (100%) indicated that no subject was destabilized during performance of ERT/SBT. All also indicated that routine medical/nursing care was uninterrupted during the performance of ERT/SBT, and the protocol was considered acceptable by all PICU staff.
Discussion
Our results demonstrate that an ERT protocol can be successfully implemented and facilitates timely extubation readiness assessment without adverse effects on key balancing measures. Our data indicate a reduction in duration of mechanical ventilation, extubation failure, and PICU stay (though the former was not statistically significant) with the implementation of an ERT protocol and that ERT can be performed safely without any destabilization of patient nor interruption in routine nursing/medical care.
Our team of 4 RTs facilitated the high adherence and consistency of ERT performance without the need for repeated training for ERT protocol use. All subjects who were extubated during office hours and weekdays had their ERT done by the RTs. If unavoidable, the need for ERTs was handed over to the on-call team for completion of the ERT protocol. With review of compliance to the protocol every 4 weeks, barriers to and opportunities for improved compliance were identified throughout the 4 PDSA cycles and addressed by the core QI team. An area for improvement was the communication of completion of ERT to the PICU attending/team by documenting the ERT in subjects' electronic medical record. Additionally, to improve the ERT rate for subsequent PDSA cycles, the team was encouraged to identify opportunities for extubation during office hours; eg, if a subject was assessed to be oversedated in the morning, the appropriate action would be to reduce sedation and reassess after a period of time. This led to ERT adherence of 90% by the fourth PDSA cycle (details of all changes after PDSA cycles are reported in Fig. 1).
Whereas our SBT utilized a trial of PS, there have been previous viewpoints on whether pre-extubation assessments should be conducted with or without PS.43,44 However, there are currently no studies that show a difference in SBT techniques on clinical outcomes,45 and our use of PS based on ETT size did not adversely impact our extubation failure rates (Table 1). This likely attests to the multiple variables such as level of sedation, diaphragm and muscle strength, fluid balance, cardiac function, and airway characteristics in addition to use of PS that impact upon extubation failure rates.45
Strengths and Limitations
One of the key strengths of our study was the high adherence rate of > 80% by the third PDSA cycle that was maintained in the fourth PDSA cycle, indicating sustainability of practice as well as a sustained reduction in median duration of mechanical ventilation. Another strength of our study was the standardization of ERT screening criteria with objective measurements for level of consciousness through the use of a formal sedation scale (State Behavioral Scale) as well as objective assessments of ventilator parameters, hemodynamic status, dosage of sedatives/analgesia, and vasoactive agents.
The main limitation of this study was that due to the single-center QI design the results of this study are poorly generalizable to other centers. Data collection was not exhaustive, and some data (eg, tracheostomy creation, hemodynamics, performance of ERT by RT vs non-RT groups) were not collected or analyzed. No compliance checks were performed; hence, ERT pass or fail recommendation may have been biased by individual assessment. Also, the SBT assessment was treated as a binary variable (pass/fail)—data on the lowest PS achieved or the number of subjects that achieved PS of 5 cm H2O were not collected. It is possible that subjects who failed the SBT could also be identified as the subjects who were unable to be weaned to a PS of 5 cm H2O.
In addition, the number of subjects who failed extubation was low, thereby making it difficult and unreliable to accurately assess the predictive value of the ERT to predict extubation success/failure. Furthermore, the short duration for pre-intervention baseline data for months of June and July 2020 may not accurately reflect historical trend of mechanical ventilation, and very few subjects (only 3 subjects) required rescue NIV. It is possible that the duration of mechanical ventilation decreased during the pre-intervention phase (Fig. 2). The period of QI (pre-intervention and post intervention) also coincided with the COVID-19 pandemic, which may have introduced bias into the demographics of the PICU population included. In addition, the study design being QI in nature also included several implementation measures that were likely to affect the outcome (eg, staff education/training, championing, change in workflow, and multiple other measures identified and addressed during the PDSA cycles). The results of this QI study were not adjusted statistically for the abovementioned confounders. Lastly, there is no consensus on the best technique for SBT, and our cohort seemed to show cardiac cases fared worse—more research is needed to determine the best SBT technique for this group.
Conclusions
We developed and implemented a sustainable, RT-driven, ERT/SBT protocol through a QI process that led to a reduction in duration of mechanical ventilation, extubation failure, and PICU length of stay (though the former was not statistically significant), suggesting that this protocol may aid better identification of patients who are ready for successful extubation.
Acknowledgments
The authors would like to thank Ms Rehana Sultana, MSc (Stat), for her review on the statistical approach and analysis of this manuscript.
Footnotes
- Correspondence: Herng Lee Tan MSc RRT RRT-ACCS RRT-NPS, Children's Intensive Care Unit, Department of Pediatric Subspecialties, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899. E-mail: tanhernglee{at}yahoo.com
Supplementary material related to this paper is available at http://rc.rcjournal.com.
The authors have disclosed no conflicts of interest.
A version of this paper was presented by Mr Aguilan at the SingHealth Duke-NUS Scientific Congress held virtually September 17–18, 2021.
The study was performed at Children's Intensive Care Unit, KK Women's and Children's Hospital, Singapore.
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