1. The Effect of NAVA on Parameters of Ventilation in the Pediatric Intensive Care Unit
Cynthia C. White, BA, RRT-NPS, AE-C, FAARC; Brandy Seger, BS, RRT-NPS; Li Lin; Susan McGee, MSN RN,CNP; Lesley Doughty, MD
Table 1. Ventilation Data after Transitioning to NAVA
Abstract
Neurally Adjusted Ventilatory Assist, (NAVA) is an FDA approved mode of ventilation that allows patients to breathe spontaneously in proportion to the normal electronic physiologic signal of the diaphragm. This feature offers the advantage of total breath cycle synchrony. Two small studies revealed a decreased peak airway pressure (PIP) for pediatric patients ventilating in the NAVA mode of ventilation in comparison to Pressure Support Ventilation, (PSV), (Breatnac, 2010, Bengtsson 2010). The purpose of this study was to determine whether PIP would decrease in NAVA in comparison to pneumatically triggered, (primarily SIMV) modes of ventilation, and trend the physiological effect on parameters that contribute to minute ventilation. Method: A convenience sample of 15 patients in the Pediatric Intensive Care Unit, (PICU) was included in our pilot study. Blood gas data was collected from our electronic charting system. PIP and other ventilation parameters were downloaded from the Servoi ventilator utilizing an electronic data card. Data was continuously collected by minute from 30-minutes prior, and 6 hours after switching to NAVA from conventional modes. Descriptive statistics were used to summarize the sample demographics and outcome measures. Mixed model repeated measures ANCOVA was conducted to test mean outcome differences among baseline(30 minutes before), 30 minutes after and 6 hours after NAVA accounting for age, gender, weight, pre-NAVA mode of ventilation and NAVA level. Post-hoc multiple comparison adjustment was applied for significant effect. Results: Patients’ ages ranged from three weeks to 15 years with a median of 1.25 years (IQR = 2.75). This sample was primarily male (66.7%) and their weight ranged from 3.6 to 77.2 kilograms (Median = 8.3, IQR = 8.7). PIP consistently and significantly decreased at both at 30 minutes and 6 hours after switching to NAVA (p = .001). See Table 1 for effect for on tidal volume, minute ventilation, PH, and pCO2. Conclusion: This data supports the theory that improved breath cycle synchrony with the diaphragm may result in improved chest wall compliance. Data from our NAVA cohort revealed a significant decrease in PIP after patients were switched to NAVA. All changes and variability in ventilation parameters were patient dependent. Overall decreases in tidal volume, and increases in RR seen to maintain minute ventilation and gas exchange.
Introduction
NAVA introduces an electrical trigger and allows patients to breathe spontaneously in proportion to the diaphragm electrical activity
Improved synchrony with the diaphragm may result in improved chest wall compliance and lower peak airway pressure
Clinical Question: In patients ventilated in NAVA in the pediatric intensive care unit, is there a decrease in Peak Airway Pressure (PIP) in NAVA in comparison to conventional modes of ventilation?
Pre-NAVA
NAVA-30 min.
NAVA-6 hrs.
p value
PIP
23.8 (2.4)
19.3 (2.4)*
21 (2.4)*
.01 VE
2.2 (.15) .7
VT I
108.1 (7.0)
87.4 (7)*
90.6 (7) *
.04
VTE
95.3 (7.7)
78.6 (7.7)
79.0 (7.7)
.13
MAP
12.8 (.8)
10.8 (.8) *
11.4 (.8) *
.001
FiO2
54.2 (3.2)
53.3 (3.2)
50.7 (3.2)
.28 RR
24.7 (4.4)
32.0 (4.4) *
30.5 (4.4) *
pCO2
52.06
54.17 .3 PH
7.39
7.38
.51 .
*Mean Age- 2.8 (4.5) y/o, range y/o; Weight- 14.7kg (18.8) kg, range kg; NAVA level 2.7 (1.9) range 1-9
Method
Continuous ventilator data collected and downloaded with electronic data card
Blood gas data was collected retrospectively from EPIC (electronic charting system)
Data collected and analyzed in SAS, per minute for 30 minutes pre-NAVA, 30 minutes post NAVA and 6 hours post NAVA
Descriptive statistics used to summarize sample demographics & outcome measures
Repeated measures ANCOVA to analyze mean outcome differences
Conclusion
PIP lower in NAVA compared to conventional ventilation in our cohort of patients
Ventilation was unchanged when switched to NAVA
RR increased and VT decreased slightly to maintain minute ventilation
Acknowledgements:
PICU staff & RT’s at Cincinnati Children’s