BACKGROUND:

In preterm infants who require mechanical ventilation (MV), volume-targeted ventilation (VTV) modes are associated with lower rates of bronchopulmonary dysplasia compared with pressure-limited ventilation. Bronchopulmonary dysplasia rates in our NICU were higher than desired, prompting quality improvement initiatives to improve MV by increasing the use of VTV.

METHODS:

We implemented and tested interventions over a 3-year period. Primary outcomes were the percentage of conventional MV hours when any-VTV mode was used and the percentage of conventional MV hours when an exclusively VTV mode was used. Exclusively VTV modes were modes in which all breaths were volume targeted. We evaluated outcomes during 3 project periods: baseline (May 2016–December 2016); epoch 1 (December 2016–October 2018), increasing the use of any-VTV mode; and epoch 2 (October 2018–November 2019), increasing the use of exclusively VTV modes.

RESULTS:

Use of any-VTV mode increased from 18 694 of 22 387 (83%) MV hours during baseline to 72 846 of 77 264 (94%) and 58 174 of 60 605 (96%) MV hours during epochs 1 and 2, respectively (P < .001). Use of exclusively VTV increased from 5967 of 22 387 (27%) during baseline to 47 364 of 77 264 (61%) and 46 091 of 60 605 (76%) of all conventional MV hours during epochs 1 and 2, respectively (P < .001). In statistical process control analyses, multiple interventions were associated with improvements in primary outcomes. Measured clinical outcomes were unchanged.

CONCLUSIONS:

Quality improvement interventions were associated with improved use of VTV but no change in measured clinical outcomes.

Bronchopulmonary dysplasia (BPD) is a common sequelae of prematurity.1  Infants with BPD have higher rates of neurodevelopmental impairment,2,3  longer lengths of stay in the NICU,4,5  higher rates of hospital readmission after NICU discharge,5,6  and higher health care use in the first years of life.4,5,7  Many risk factors for BPD, including extreme prematurity, chorioamnionitis, and lower birth weight, are difficult to modify.8  One potentially modifiable risk factor for BPD is mechanical ventilation (MV) use.

Although lifesaving for many preterm infants, MV is strongly associated with the development of BPD.9  Even with increased use of noninvasive respiratory support, >80% of infants born <29 weeks' gestation receive MV in the NICU.1  For these infants, volume-targeted ventilation (VTV) modes, in which the ventilator targets a set tidal volume and reduces support as lung compliance improves, has been shown to be superior to pressure-limited ventilation (PLV) modes,10  in which the ventilator delivers a set pressure with each breath and the tidal volume varies with changes in lung mechanics or infant effort. Compared with PLV, VTV reduces the incidence of death or BPD by 27%.11  Despite this, the majority of neonatologists in the United States primarily use PLV.12 

In early 2016, we noted the incidence of BPD in our NICU was higher than desired compared with national benchmarks. We therefore began a coordinated, unit-wide effort to target modifiable risk factors for BPD. Our team identified MV as an area of potential improvement. In this article, we describe a quality improvement (QI) project to increase the use of VTV during conventional MV with the goal of decreasing the rate of BPD in our NICU.

We performed this project in the 98-bed, level IV,13  academic NICU of the Vanderbilt University Medical Center. This NICU includes 2 geographically distinct units in separate but contiguous hospitals: a 78-bed unit with single-patient rooms primarily housing outborn infants and infants with congenital anomalies and/or surgical conditions, and a 20-bed, open-bay unit primarily housing inborn preterm infants. The NICU staff includes ∼280 neonatal nurses, 50 pediatric respiratory therapists (RTs), 45 advanced practice providers (APPs), 25 neonatologists, and 11 neonatal-perinatal medicine fellows.

Our NICU has nearly 1500 admissions annually and is supported by a full range of subspecialists. Patients include preterm infants (≥22 weeks' gestation), infants with congenital anomalies, including complex surgical and cardiac conditions, and term infants with respiratory or other medical conditions. Approximately 25% of infants admitted to the NICU receive MV, including both conventional and high-frequency ventilation. The Dräger Evita Infinity V500 (Drägerwerk AG and Co, Lübeck, Germany) ventilator is used for conventional MV. Before project interventions, conventional ventilation consisted of a mixture of 9 VTV and PLV modes (Supplemental Information). Although only physicians (neonatologists and fellows) and APPs can write orders to change ventilator settings, physicians, APPs, and RTs are permitted to physically adjust ventilator settings.

All infants admitted to the NICU who received conventional MV were eligible for the interventions. We hypothesized that including all ventilated infants would be more easily implemented than limiting interventions to only infants at highest risk for BPD (<1500 g at birth). We excluded infants while they were receiving high-frequency ventilation or extracorporeal membrane oxygenation and those with congenital lung anomalies (eg, congenital diaphragmatic hernia), a tracheostomy, or an endotracheal tube leak >80% when a VTV approach could not be reliably used14  and those infants receiving end-of-life care.

We followed 2 main project outcomes: (1) percentage of conventional MV hours when a synchronized VTV mode was used and (2) percentage of conventional MV hours when a synchronized, exclusively VTV mode was used. We considered ventilator modes in which the majority of breaths were volume-targeted as a VTV mode. Ventilator modes in which all breaths, whether initiated by the ventilator or the infant, were volume-targeted and potentially less injurious to the lung10  were classified as exclusively VTV modes (Supplemental Information). Secondary outcomes included mortality, BPD, duration of MV, supplemental oxygen at discharge, and severe intraventricular hemorrhage. High-frequency ventilation use was included as a balancing measure. We prospectively collected data through medical records review and, beginning in September 2016, augmented with data downloaded directly from the ventilators. During the project, concerns arose that increased VTV use was resulting in greater ventilator alarm frequency. We therefore calculated ventilator alarm rates for a convenience sample of patients during each period as a further balancing measure. No value metrics were followed.

Our multidisciplinary QI team consisted of neonatal nurses, RTs, APPs, neonatal fellows, neonatologists, medical and nursing leadership, a systems engineer, and a data analyst. We evaluated outcomes in 3 periods: baseline, no interventions (May 1, 2016–December 18, 2016); epoch 1, improving the use of VTV modes and decreasing PLV use (December 19, 2016–August 31, 2018); and epoch 2, improving the use of exclusively VTV modes (September 1, 2018–August 31, 2019). These dates were chosen because the main outcome of interest during epoch 1 was any-VTV use, and the main outcome during epoch 2 was exclusively VTV use. Before testing interventions, we evaluated baseline data; performed structured observations of the MV workflow, including clinician interviews and simple cognitive walkthroughs (structured technique for evaluating software and computer interfaces)15  for choosing ventilator modes; generated a process map with failure modes and effect analysis for MV; identified SMART aims for each epoch; and generated a key driver diagram for iterative testing (Fig 1). We used the Influencer Change Model16  as our framework to develop interventions for behavioral change, attempting to target all 6 potential sources of influence, and the Model for Improvement17  as our overall improvement methodology. Interventions were iteratively tested through plan-do-study-act (PDSA) cycles and ramps. Goals of our interventions comprised 4 general categories: (1) standardization of MV processes and practices, (2) improved team communication, (3) system optimization to facilitate use of VTV, and (4) education regarding the evidence for superiority of VTV and the capabilities of our ventilators. In Table 1, we list interventions, their components, Influencer Change Model framework, and timing of testing and implementation for each intervention.

FIGURE 1

Final key driver diagram for VTV project. EHR, electronic health record; ETT, endotracheal tube; SMART, specific, measurable, achievable, realistic, timely; VSB, ventilator setup brief.

FIGURE 1

Final key driver diagram for VTV project. EHR, electronic health record; ETT, endotracheal tube; SMART, specific, measurable, achievable, realistic, timely; VSB, ventilator setup brief.

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TABLE 1

Interventions Tested and Implemented During the Project Period,

PDSA Ramps and InterventionsIntervention ComponentsInfluencer Theory CategoryTimelinea
PDSA ramp 1: standardize process for initiating MV Developed and tested a standardized script for RT and providers to review when placing a patient on MV. This was termed the Ventilator Setup Brief (Supplemental Information). Mounted laminated scripts on the screens of all ventilators after cleaning Social motivation, social ability Began testing: December 19, 2016. Full implementation: March 7, 2017 
PDSA ramp 2: develop and implement standardized evidence informed diagnosis-specific MV pathways Developed diagnosis-specific MV pathways for ventilator settings in our NICU (Supplemental Information). Provided education on these pathways to clinicians in multiple forums. Mounted “pathways” in visible locations in the RT offices and on the NICU webpage Personal ability, social ability Began testing: January 3, 2017. Full implementation: June 21, 2017 
PDSA ramp 3: implement daily respiratory care huddle on rounds Reconfigured RT workflow to allow RTs to manage patients on a provider team and not according to location in the NICU. Adjusted rounding times so RT can round with patient team. Standardized the content for RT participation in rounds Social motivation, social ability Began testing: February 5, 2017. Full implementation: April 15, 2017 
PDSA ramp 4: implement night shift respiratory care team huddle Introduced a nightly “huddle” for all physicians, APPs, RTs, and charge nurse to discuss respiratory care plans for all ventilated patients. Standardized script and content Social motivation, social ability Began testing: February 28, 2017. Full implementation: April 28, 2017 
Reformat ventilator interface screens to include preferred VTV modes Added PC-PSV/VG to home screen of ventilator. Removed all unsynchronized modes from home screen to discourage either intentional or inadvertent use Structural ability Implementation: January 20, 2017 
Educate providers on evidence for VTV use, ventilator capabilities, and use of VTV in our NICU Provided education provided at faculty, RT, APP, and nurse staff meetings. Provided data on current use of VTV at monthly Neonatology Division Mortality, Morbidity, and Improvement conferences. Held in-service meeting for clinicians and RTs with Dräger representative. Presented data on current use of VTV modes to groups of clinicians Personal motivation, personal ability, structural motivation Multiple times throughout entire project period 
Optimize EHR fields for use of VTV modes Added rows to EHR flowsheet to allow easier charting of VTV modes. Developed a MV order set that included all preferred VTV modes Structural ability Implementation: October 2, 2018 
PDSA ramp 5: introduce PC-AC/VG Introduced use of a time-cycled mode with all breaths volume-targeted (PC-AC/VG). Slowly expanded use of this mode through additional patient populations in the NICU. Developed “super-users” to provide at-the-elbow clinical decision support and troubleshooting for clinicians new to this mode. Affixed brief information sheets for using PC-AC/VG to all ventilators (Supplemental Information). Provided just-in-time teaching to nurses by RT at beginning of shifts when infant is ventilated in PC-AC/VG mode Personal ability, social ability, structural ability Began testing: October 24, 2018. Full implementation: January 16, 2019 
PDSA ramp 6: add a ventilator screen option displaying all variables potentially important for extubation in PC-AC/VG Used literature review and provider interviews after implementation of PC-AC/VG to determine respiratory variables important for monitoring and extubation. Developed and implemented ventilator “Screen 3” that displays all of these variables in one place Structural ability Began testing: January 15, 2019. Full implementation:
March 13, 2019 
Reformat ventilator interface screens to include PC-AC/VG Added PC-AC/VG to home screen of ventilator for ease of use. Removed all PLV modes from home screen to discourage either intentional or inadvertent use Structural ability Implementation: April 12, 2019 
PDSA Ramps and InterventionsIntervention ComponentsInfluencer Theory CategoryTimelinea
PDSA ramp 1: standardize process for initiating MV Developed and tested a standardized script for RT and providers to review when placing a patient on MV. This was termed the Ventilator Setup Brief (Supplemental Information). Mounted laminated scripts on the screens of all ventilators after cleaning Social motivation, social ability Began testing: December 19, 2016. Full implementation: March 7, 2017 
PDSA ramp 2: develop and implement standardized evidence informed diagnosis-specific MV pathways Developed diagnosis-specific MV pathways for ventilator settings in our NICU (Supplemental Information). Provided education on these pathways to clinicians in multiple forums. Mounted “pathways” in visible locations in the RT offices and on the NICU webpage Personal ability, social ability Began testing: January 3, 2017. Full implementation: June 21, 2017 
PDSA ramp 3: implement daily respiratory care huddle on rounds Reconfigured RT workflow to allow RTs to manage patients on a provider team and not according to location in the NICU. Adjusted rounding times so RT can round with patient team. Standardized the content for RT participation in rounds Social motivation, social ability Began testing: February 5, 2017. Full implementation: April 15, 2017 
PDSA ramp 4: implement night shift respiratory care team huddle Introduced a nightly “huddle” for all physicians, APPs, RTs, and charge nurse to discuss respiratory care plans for all ventilated patients. Standardized script and content Social motivation, social ability Began testing: February 28, 2017. Full implementation: April 28, 2017 
Reformat ventilator interface screens to include preferred VTV modes Added PC-PSV/VG to home screen of ventilator. Removed all unsynchronized modes from home screen to discourage either intentional or inadvertent use Structural ability Implementation: January 20, 2017 
Educate providers on evidence for VTV use, ventilator capabilities, and use of VTV in our NICU Provided education provided at faculty, RT, APP, and nurse staff meetings. Provided data on current use of VTV at monthly Neonatology Division Mortality, Morbidity, and Improvement conferences. Held in-service meeting for clinicians and RTs with Dräger representative. Presented data on current use of VTV modes to groups of clinicians Personal motivation, personal ability, structural motivation Multiple times throughout entire project period 
Optimize EHR fields for use of VTV modes Added rows to EHR flowsheet to allow easier charting of VTV modes. Developed a MV order set that included all preferred VTV modes Structural ability Implementation: October 2, 2018 
PDSA ramp 5: introduce PC-AC/VG Introduced use of a time-cycled mode with all breaths volume-targeted (PC-AC/VG). Slowly expanded use of this mode through additional patient populations in the NICU. Developed “super-users” to provide at-the-elbow clinical decision support and troubleshooting for clinicians new to this mode. Affixed brief information sheets for using PC-AC/VG to all ventilators (Supplemental Information). Provided just-in-time teaching to nurses by RT at beginning of shifts when infant is ventilated in PC-AC/VG mode Personal ability, social ability, structural ability Began testing: October 24, 2018. Full implementation: January 16, 2019 
PDSA ramp 6: add a ventilator screen option displaying all variables potentially important for extubation in PC-AC/VG Used literature review and provider interviews after implementation of PC-AC/VG to determine respiratory variables important for monitoring and extubation. Developed and implemented ventilator “Screen 3” that displays all of these variables in one place Structural ability Began testing: January 15, 2019. Full implementation:
March 13, 2019 
Reformat ventilator interface screens to include PC-AC/VG Added PC-AC/VG to home screen of ventilator for ease of use. Removed all PLV modes from home screen to discourage either intentional or inadvertent use Structural ability Implementation: April 12, 2019 

EHR, electronic health record.

a

Denotes when the first PDSA cycle was started and when the fully tested product of the testing was implemented throughout the entire NICU.

Clinical variables, outcomes, and balancing measures were compared between baseline and the 2 epochs by using analysis of variance for continuous parametric data, Kruskal–Wallis test for continuous nonparametric data, and χ2 tests for dichotomous data.

We used time series graphs to evaluate the effectiveness of our interventions and tests of change in real time as the project was implemented and XmR charts18  to analyze full project data. During active improvement periods, we used the Western Electric rules19  to identify special-cause variation.20  During sustainment (after active testing had ceased), we used only the rule for shift to adjust our center line and investigated all points outside of the control limits. Because our primary unit of measurement was a ventilator hour, data both within and between subgroups were potentially autocorrelated (nonindependent) because an infant may have multiple ventilator hours within a week and be ventilated across multiple weeks. We therefore calculated the autocorrelation coefficient21  to ensure the ability to use statistical process control (SPC) methods for monitoring. The autocorrelation coefficient early during the baseline period was 0.08, below the recommended threshold of 0.5, confirming our ability to use SPC charts for monitoring.21 

To ensure our main analyses were robust to autocorrelation, we completed 2 interrupted time series (ITS) (autoregressive integrated moving average) analyses.22  The first ITS analysis used any-VTV mode as the outcome and introduced interruptions at the beginning of each epoch. The second ITS analysis used exclusively VTV mode use as the outcome and introduced interruptions at the times of ventilator interface reformatting, the 2 interventions temporally related to the largest increases during real-time SPC monitoring.

During the baseline period, we noted episodes of MV when an unsynchronized ventilator mode (the ventilator delivers a breath whether an infant is breathing or not) was inadvertently used. Thereafter, we also followed a g-chart20,23  of the number of conventional MV hours between events in which an infant received an unsynchronized mode.

Finally, to assess the overall effect of our project on clinical outcomes in very low birth weight (VLBW) infants, we developed multivariable logistic or negative binomial regression models with a dummy variable denoting the project period for all secondary outcomes. These analyses were limited to VLBW infants inborn or transferred in by 72 hours of age and adjusted for multiple potential confounders. Analyses were performed in Stata/MP 15.1 (StataCorp, College Station, TX), and SPC charts were constructed by using QI Macros for Excel v. 2014.1 (KnowWare International Inc, Denver, CO). Our institutional review board reviewed and exempted the project under a waiver for QI.

During the project period, 1269 infants received MV in the NICU for a total of 275 202 ventilator hours. Of these, 1225 of 1269 (97%) infants met project inclusion criteria for 213 751 (78%) ventilator hours. Reasons for exclusion from the project and the breakdown of ventilator time across the periods are shown in Figure 2. Patient characteristics (Table 2) were similar across the periods except that VLBW infants constituted a higher percentage of admissions during the baseline period (P = .04).

FIGURE 2

Infants receiving MV during the project. 1Total is less than the sum of infants during the 3 periods as some infants were ventilated during multiple periods. 2Total days is less than the sum as some days were excluded for multiple reasons; Cong, congenital; ECMO, extracorporeal membrane oxygenation; ETT, endotracheal tube.

FIGURE 2

Infants receiving MV during the project. 1Total is less than the sum of infants during the 3 periods as some infants were ventilated during multiple periods. 2Total days is less than the sum as some days were excluded for multiple reasons; Cong, congenital; ECMO, extracorporeal membrane oxygenation; ETT, endotracheal tube.

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TABLE 2

Demographic and Clinical Characteristics for All Eligible Mechanically Ventilated Infants by Period of NICU Admission

VariableBaseline (n = 235)Epoch 1 (n = 642)Epoch 2 (n = 348)P
Gestational age, wk, median (IQR) 32 (27–37) 34 (28–38) 34 (28–37) .15 
Gestational age <28 wk, n (%) 62 (26) 157 (25) 86 (25) .84 
Birth wt, g, median (IQR) 1725 (1000–3000) 2145 (1045–3130) 2098 (1022–3057) .23 
Birth wt <1500 g, n (%) 103 (44) 221 (34) 128 (37) .04 
Male, n (%) 124 (53) 370 (58) 182 (52) .17 
Inborn, n (%) 124 (53) 339 (53) 189 (54) .89 
Day of NICU admission,a median (IQR) 0 (0–1) 0 (0–1) 0 (0–1) .77b 
Antenatal steroids, all infants,cn (%) 114 (50) 271 (44) 171 (50) .11 
Antenatal steroids, infants <34 wk,dn (%) 107 (86) 230 (78) 118 (81) .21 
Apgar score <3 at 5 min, n (%) 22 (9) 87 (14) 42 (12) .24 
Surfactant treatment, n (%) 135 (57) 335 (52) 175 (50) .22 
CRIB score, median (IQR) 2 (0–4) 3 (0–5) 3 (0–6) .17b 
Congenital anomaly, n (%) 82 (35) 245 (38) 148 (43) .16 
Surgery during NICU course, n (%) 101 (43) 255 (40) 154 (44) .35 
VariableBaseline (n = 235)Epoch 1 (n = 642)Epoch 2 (n = 348)P
Gestational age, wk, median (IQR) 32 (27–37) 34 (28–38) 34 (28–37) .15 
Gestational age <28 wk, n (%) 62 (26) 157 (25) 86 (25) .84 
Birth wt, g, median (IQR) 1725 (1000–3000) 2145 (1045–3130) 2098 (1022–3057) .23 
Birth wt <1500 g, n (%) 103 (44) 221 (34) 128 (37) .04 
Male, n (%) 124 (53) 370 (58) 182 (52) .17 
Inborn, n (%) 124 (53) 339 (53) 189 (54) .89 
Day of NICU admission,a median (IQR) 0 (0–1) 0 (0–1) 0 (0–1) .77b 
Antenatal steroids, all infants,cn (%) 114 (50) 271 (44) 171 (50) .11 
Antenatal steroids, infants <34 wk,dn (%) 107 (86) 230 (78) 118 (81) .21 
Apgar score <3 at 5 min, n (%) 22 (9) 87 (14) 42 (12) .24 
Surfactant treatment, n (%) 135 (57) 335 (52) 175 (50) .22 
CRIB score, median (IQR) 2 (0–4) 3 (0–5) 3 (0–6) .17b 
Congenital anomaly, n (%) 82 (35) 245 (38) 148 (43) .16 
Surgery during NICU course, n (%) 101 (43) 255 (40) 154 (44) .35 

CRIB, Clinical Risk Index for Babies; IQR, interquartile range.

a

Day 0 is the day of birth.

b

Kruskal–Wallis test.

c

Missing data for 36 infants.

d

Denominator is 125 in baseline, 294 in epoch 1, 145 in epoch 2.

Both main outcomes increased during the project in the entire eligible population and VLBW infants (P < .001 for all comparisons) (Table 3). Use of any-VTV mode increased from 18 694 of 22 387 (83%) conventional MV hours during the baseline period to 72 846 of 77 264 (94%) and 58 174 of 60 605 (96%) of conventional MV hours during epochs 1 and 2, respectively (P < .001). Use of an exclusively VTV mode increased from 5967 of 22 387 (27%) during baseline to 47 364 of 77 264 (61%) and 46 091 of 60 605 (76%) of all conventional MV hours during epochs 1 and 2, respectively (P < .001).

TABLE 3

Project Outcome and Balancing Measures for Mechanically Ventilated Infants by Project Period

OutcomesBaselineEpoch 1Epoch 2Pa
All ventilated infants     
 Outcome measures     
  Total ventilator hours 33 794 103 920 76 037 — 
  Conventional ventilation hours, n (% of total) 22 387 (66) 77 264 (74) 60 605 (80) <.001 
  Any-VTV mode used, h (%)b 18 694 (83) 72 846 (94) 58 174 (96) <.001 
  Exclusively VTV mode used, h (%)b 5967 (27) 47 364 (61) 46 091 (76) <.001 
 Balancing measure     
  High-frequency ventilation h, n (% of total) 11 407 (34) 26 656 (26) 15 432 (20) <.001 
  Alarms per conventional ventilator h (95% CI)b 12.53 (12.45 to 12.6) 16.96 (16.88 to 16.99) 16.43 (16.39 to 16.47) <.001 
VLBW infants     
 Outcome measures     
  Total ventilator h 21 588 68 531 39 148 — 
  Conventional ventilation h, n (% of total) 12 384 (57) 45 141 (66) 28 120 (72) <.001 
  Any-VTV mode used, h (%)b 9985 (81) 42 689 (95) 27 173 (97) <.001 
  Exclusively VTV mode used, h (%)b 2697 (22) 24 235 (54) 21 498 (77) <.001 
OutcomesBaselineEpoch 1Epoch 2Pa
All ventilated infants     
 Outcome measures     
  Total ventilator hours 33 794 103 920 76 037 — 
  Conventional ventilation hours, n (% of total) 22 387 (66) 77 264 (74) 60 605 (80) <.001 
  Any-VTV mode used, h (%)b 18 694 (83) 72 846 (94) 58 174 (96) <.001 
  Exclusively VTV mode used, h (%)b 5967 (27) 47 364 (61) 46 091 (76) <.001 
 Balancing measure     
  High-frequency ventilation h, n (% of total) 11 407 (34) 26 656 (26) 15 432 (20) <.001 
  Alarms per conventional ventilator h (95% CI)b 12.53 (12.45 to 12.6) 16.96 (16.88 to 16.99) 16.43 (16.39 to 16.47) <.001 
VLBW infants     
 Outcome measures     
  Total ventilator h 21 588 68 531 39 148 — 
  Conventional ventilation h, n (% of total) 12 384 (57) 45 141 (66) 28 120 (72) <.001 
  Any-VTV mode used, h (%)b 9985 (81) 42 689 (95) 27 173 (97) <.001 
  Exclusively VTV mode used, h (%)b 2697 (22) 24 235 (54) 21 498 (77) <.001 

—, not applicable.

a

χ2 test.

b

Conventional ventilation hours were used as the denominator to calculate percentages for this outcome.

Using XmR charts, we observed special-cause variation multiple times during the project for both outcomes. For the use of any-VTV mode (Fig 3), we noted a shift with 8 points above the center line temporally after the following: (1) beginning to test a standardized process for initiating MV (PDSA ramp no. 1), (2) implementing diagnosis-based MV “pathways” unit-wide (PDSA ramp no. 2), and (3) reformatting the ventilator interface to remove all PLV choices from the home screen. After improvements and tightening of our control limits, we also noted multiple episodes of points below the lower control limit. We investigated these in real time, and, in nearly all cases, this variation was caused by 1 or more older infants with BPD who were being ventilated with a PLV mode. We noted 4 shifts in the use of an exclusively VTV mode (Fig 4) during the project. Improvements were temporally related to (1) reformatting the ventilator interface screens to include all available VTV modes used at that time, (2) beginning to test and implement a new exclusively VTV mode (pressure control–assist control with volume guarantee [PC-AC/VG]), and (3) reformatting the ventilator interface to remove all PLV modes from the home screen and include PC-AC/VG as a choice. A decrease in exclusively VTV mode use was temporally associated with the beginning of a new academic year and an influx of new faculty, staff, and trainees.

FIGURE 3

Annotated XmR chart of any-VTV mode use. Although weekly data were followed during the project, only every other week is shown for brevity. CL, center line; LCL, lower control limit; UCL, upper control limit.

FIGURE 3

Annotated XmR chart of any-VTV mode use. Although weekly data were followed during the project, only every other week is shown for brevity. CL, center line; LCL, lower control limit; UCL, upper control limit.

Close modal
FIGURE 4

Annotated XmR chart of exclusively VTV mode use. Although weekly data were followed during the project, only every other week is shown for brevity. CL, center line; UCL, upper control limit.

FIGURE 4

Annotated XmR chart of exclusively VTV mode use. Although weekly data were followed during the project, only every other week is shown for brevity. CL, center line; UCL, upper control limit.

Close modal

Using ITS analyses, we noted an immediate and sustained 9.5% (95% confidence interval [CI]: 2.1% to 16.8%, P = .01) increase in any-VTV mode use after beginning interventions in epoch 1 without a change in the slope (Supplemental Information). We also observed an immediate 39% (95% CI: 26.5 to 51.3, P < .001) increase in exclusively VTV mode use after reformatting the ventilator interface screens in January 2017, with no change in the slope of use across these periods (Supplemental Information). Although the second ventilator screen reformatting in April 2019 was associated with special-cause variation in SPC analyses, this change was not significant in the ITS analysis (30.8%, 95% CI: −38% to 100%, P = .38).

We unexpectedly noted use of an unsynchronized mode, pressure control–continuous mandatory ventilation with volume guarantee (PC-CMV/VG), during the baseline period. Using clinical workflow observations, we found that these events mostly occurred while clinicians were attempting to navigate the ventilator screens to choose a commonly used exclusively VTV mode, pressure control–pressure support ventilation with volume guarantee (PC-PSV/VG). Using this finding as the impetus to modify the ventilator interface home screens, we noted 2 episodes of special-cause variation on the g-chart corresponding to prolonged periods of time when PC-CMV/VG was not used, both occurring after reformatting the ventilator user interface (Fig 5).

FIGURE 5

Annotated g-chart of the number of conventional MV hours between use of an unsynchronized ventilator mode. At project conclusion, no unsynchronized mode use had occurred in ∼75 000 consecutive conventional ventilation hours. CL, center line; UCL, upper control limit.

FIGURE 5

Annotated g-chart of the number of conventional MV hours between use of an unsynchronized ventilator mode. At project conclusion, no unsynchronized mode use had occurred in ∼75 000 consecutive conventional ventilation hours. CL, center line; UCL, upper control limit.

Close modal

The frequency of ventilator alarms per hour increased during the project periods from 12.53 (95% CI: 12.45 to 12.6) during baseline to 16.96 (95% CI: 16.88 to 16.99) and 16.43 (95% CI: 16.39 to 16.47) during epochs 1 and 2, respectively (P < .001). The majority of alarms during all periods were related to peak inspiratory pressure limits (data not shown).

Despite increasing the use of VTV, clinical outcomes in VLBW infants in our NICU, including mortality, BPD, severe intraventricular hemorrhage, and duration of MV, remained unchanged after adjusting for patient characteristics (Table 4).

TABLE 4

Clinical Outcomes for VLBW Infants By Period of Admission

OutcomesBaseline (n = 84)Epoch 1 (n = 177)Epoch 2 (n = 109)Adjusted odds/incidence rate ratio (95% CI)a
Death, n (%) 12 (14) 41 (23) 31 (28) Baseline: Ref., epoch 1: 1.1 (0.5 to 2.5), epoch 2: 1.8 (0.8 to 4.2) 
Death or BPD, n (%) 51 (61) 121 (68) 84 (76) Baseline: Ref., epoch 1: 0.9 (0.5 to 1.7), epoch 2: 1.9 (0.9 to 3.9) 
BPD, n (%) 43 (51) 83 (47) 55 (51) Baseline: Ref., epoch 1: 0.8 (0.5 to 1.4), epoch 2: 1 (0.5 to 1.8) 
Supplemental oxygen at discharge, n (%) 32 (38) 79 (45) 56 (51) Baseline: Ref., epoch 1: 0.9 (0.5 to 1.7), epoch 2: 1.5 (0.7 to 2.9) 
Severe IVH,bn (%) 11 (13) 22 (13) 13 (12) Baseline: Ref., epoch 1: 0.9 (0.4 to 2.1), epoch 2: 0.9 (0.3 to 2.3) 
Total duration of MV, d, median (IQR) 5.5 (2–20) 6 (2–19) 4 (2–13) Baseline: Ref., epoch 1: 1.1 (0.8 to 1.5), epoch 2: 0.9 (0.6 to 1.3) 
OutcomesBaseline (n = 84)Epoch 1 (n = 177)Epoch 2 (n = 109)Adjusted odds/incidence rate ratio (95% CI)a
Death, n (%) 12 (14) 41 (23) 31 (28) Baseline: Ref., epoch 1: 1.1 (0.5 to 2.5), epoch 2: 1.8 (0.8 to 4.2) 
Death or BPD, n (%) 51 (61) 121 (68) 84 (76) Baseline: Ref., epoch 1: 0.9 (0.5 to 1.7), epoch 2: 1.9 (0.9 to 3.9) 
BPD, n (%) 43 (51) 83 (47) 55 (51) Baseline: Ref., epoch 1: 0.8 (0.5 to 1.4), epoch 2: 1 (0.5 to 1.8) 
Supplemental oxygen at discharge, n (%) 32 (38) 79 (45) 56 (51) Baseline: Ref., epoch 1: 0.9 (0.5 to 1.7), epoch 2: 1.5 (0.7 to 2.9) 
Severe IVH,bn (%) 11 (13) 22 (13) 13 (12) Baseline: Ref., epoch 1: 0.9 (0.4 to 2.1), epoch 2: 0.9 (0.3 to 2.3) 
Total duration of MV, d, median (IQR) 5.5 (2–20) 6 (2–19) 4 (2–13) Baseline: Ref., epoch 1: 1.1 (0.8 to 1.5), epoch 2: 0.9 (0.6 to 1.3) 

Restricted to VLBW infants inborn or transferred in before 72 h of life who received MV. IVH, intraventricular hemorrhage; Ref., reference.

a

Multivariable logistic or negative binomial regression models adjusting for period of admission, gestational age, birth weight, sex, antenatal steroids, Clinical Risk Index for Babies score, 5-min Apgar score, and surfactant receipt as sample size allowed.

b

IVH status is unknown for 15 infants who did not receive a head ultrasound examination before death or discharge. Severe IVH is defined at grade 3 or 4.

We have shown that focused QI interventions over a 3-year period improved the evidence-based use of MV in our NICU, with a 16% relative increase (13% absolute) in the use of any-VTV mode, 280% relative increase (49% absolute) in the use of exclusively VTV modes, and nearly complete elimination of the use of unsynchronized modes of MV. The greatest improvements were temporally related to standardization of MV processes and practices and reformatting the ventilator interface screens so that it was easier for clinicians to choose a preferred VTV mode and more difficult to choose a PLV mode. To our knowledge, this is the first QI report to describe interventions to improve evidence-based use of neonatal MV. Disappointingly, these improvements in MV were not associated with improved clinical outcomes, after adjusting for patient characteristics.

The 2 largest improvements in VTV use occurred after changes to the ventilator interface home screens. We made the first adjustment after noting that clinicians were inadvertently selecting an unsynchronized mode while trying to choose a VTV mode. Before adjusting the screens, clinicians navigated through 4 menus, with multiple options at each to choose the preferred VTV mode. We found that at the second menu, clinicians were inadvertently choosing an unsynchronized mode with an abbreviation similar to the preferred VTV mode (PC-CMV/VG versus PC-PSV/VG). After moving PC-PSV/VG to the home screen, we observed special-cause variation on the g-chart with a prolonged period of time between use of PC-CMV/VG. Unexpectedly, we also saw the use of PC-PSV/VG greatly increase. During postimplementation interviews, several clinicians stated that they did not use PC-PSV/VG before reformatting the screens because they were concerned they would make an error while navigating the multiple menus. Our findings underscore the importance of user-centered design (UCD)24  methods in implementing technology-intensive interventions such as MV. To date, no studies have described UCD methods to optimize neonatal MV. With our findings, we suggest that optimizing local systems using human factors engineering methods25  such as UCD could greatly improve the quality of neonatal MV.

Several potential reasons may explain why improved use of VTV was not associated with improved clinical outcomes for VLBW infants. First, our NICU had relatively high VTV use in VLBW infants at baseline (81% of MV time). Researchers demonstrating the efficacy of VTV have compared exclusive use of VTV to exclusive use of PLV.10,11  Before our project, many infants already received VTV for most of their MV course and thus may have already gained its benefits. Second, multiple factors contribute to the clinical outcomes we assessed. For example, potentially modifiable risk factors for BPD include the type and duration of MV,911  postnatal growth,26  and fluid and sodium intake early in life.27,28  Although we adjusted for many factors in our analyses, we could not adjust for all potential confounders. Third, although we saw improvements in the use of MV modes, we were unable to determine if the ventilation strategies used by clinicians were appropriate for each patient, with tidal volumes selected on the basis of patient pathology.29  Future work in our NICU will focus on assessing the VTV strategies used and evaluating whether these agree with available evidence.

In addition to improving VTV use, we observed an increase in ventilator alarm frequency during our project. This increase was driven mainly by peak inspiratory pressure alarms, in which the set tidal volume was not delivered because of a set pressure limit being met. Because limited data exist on MV alarms in the NICU, we are not able to say how much of the increase in alarms was expected30  and how much could have been mitigated. This increasing alarm frequency has the potential to result in alarm fatigue and increased workload and stress for bedside providers and parents. Although some expert recommendations for alarm limits during VTV exist,31  future work should define the epidemiology of ventilator alarms in the NICU and develop strategies to mitigate alarms commonly seen with the use of VTV.

Although successful in our NICU, our interventions may not be generalizable to all NICUs. Specifically, our strategy to reformat the ventilator interfaces may not be as easily implemented in NICUs using ventilators in which the screens cannot be modified. In addition, our high baseline rate of VTV suggests that clinicians were already aware of the evidence regarding efficacy of VTV compared with PLV. In NICUs with lower baseline use of VTV, more attention, effort, and education will likely be required to target the drivers of knowledge and buy-in to the available evidence for choosing a ventilation mode.

We have shown that specific QI interventions in our NICU were associated with improved use of VTV and decreased use of unsynchronized and PLV modes but no change in clinical outcomes. Our work can be used as a blueprint for QI teams who desire to implement VTV use in their unit.

We thank the RTs, bedside nurses, nurse practitioners, and physicians who took part in the improvement initiatives, generated ideas for improvement, and provided feedback and testing of interventions in clinical practice.

Dr Hatch and Mrs Sala conceptualized and designed the improvement projects, oversaw improvement efforts, collected and analyzed data, and drafted the initial manuscript; Drs Araya, Morris, Guttentag, Grubb, Stark, and Markham, Mrs Bolton and Rivard, and Mr Rivard assisted in designing and implementing improvement interventions, interpreting real-time data during the improvement efforts, and critically reviewing the manuscript; Ms McNeer designed and performed the statistical analyses and critically reviewed the manuscript; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

FUNDING: Research reported in this publication was supported by the Katherine Dodd Faculty Scholars program (L.D.H.) and the Vanderbilt Department of Pediatrics Turner-Hazinski Research Award (L.D.H.).

     
  • APP

    advanced practice provider

  •  
  • CI

    confidence interval

  •  
  • BPD

    bronchopulmonary dysplasia

  •  
  • ITS

    interrupted time series

  •  
  • MV

    mechanical ventilation

  •  
  • PC-AC/VG

    pressure control–assist control with volume guarantee

  •  
  • PC-CMV/VG

    pressure control–continuous mandatory ventilation with volume guarantee

  •  
  • PC-PSV/VG

    pressure control–pressure support ventilation with volume guarantee

  •  
  • PDSA

    plan-do-study-act

  •  
  • PLV

    pressure-limited ventilation

  •  
  • QI

    quality improvement

  •  
  • RT

    respiratory therapist

  •  
  • SPC

    statistical process control

  •  
  • UCD

    user-centered design

  •  
  • VLBW

    very low birth weight

  •  
  • VTV

    volume-targeted ventilation

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Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.

Supplementary data