UNDERSTANDING NEONATAL WAVEFORM GRAPHICS. Brandon Kuehne, MBA, RRT-NPS, RPFT Director- Neonatal Respiratory Services

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1 UNDERSTANDING NEONATAL WAVEFORM GRAPHICS Brandon Kuehne, MBA, RRT-NPS, RPFT Director- Neonatal Respiratory Services

2 Disclosures Purpose: To enhance bedside staff s knowledge of ventilation and oxygenation support to the neonate. To support and encourage the use of the proximal flow probe via the explanation of theory of operation. To encourage the practical application of waveform analysis associated with neonatal pressure ventilation. Objectives: Identify and discuss the various clinical types of graphic waveforms provided at bedside to the neonatal caregiver. Describe the common types neonatal ventilatory complications that can be diagnosed and corrected with the proper application of graphic waveform identification and analysis. The Planning Committee and Faculty of this activity have no disclosed conflicts of interest related to this content. Completion Criteria: In order to receive Continuing Nursing Education (CNE) credit, you must attend 80% of the program. No commercial support was received for this program Nationwide Children s Hospital s accreditation as a provider refers to recognition of educational activities only and does not imply ANCC Commission on Accreditation, Ohio Board of Nursing, ONA or Children s Hospital s approval or endorsement of any product.

3 What is Respiration? Ventilation The removal of CO 2 Oxygenation The uptake of 0 2

4 How do I achieve these items, Mechanically? Ventilation component is comprised of two parts Tidal Volumes Rate Together they make: V t X RR = minute volume In Neonate approx. 200ml/kg/min Oxygenation component consists of a combination of: Fractional inspired Oxygen (Fi0 2 ) Alveolar pressure (Mean Airway Pressure)

5 Oxygenation FiO 2 21% - 100% Alveolar Pressure (MAP) Distending the alveoli allows oxygen exchange to take place over greater period of time. The biggest components that affect the MAP are PEEP CPAP PIP and Rate and Insp. Time affect MAP to a much lesser extent

6 Ventilation Tidal Volume- Effective V t = Exhaled V t ((PIP PEEP) x Tubing compliance) wt.(kg) Most ventilators can display this number in real time if the proper patient weight is inputted (targets are usually 4-6ml/kg for newborns)

7 Ventilation Respiratory Rate Frequency that alveoli expand and contract Good starting numbers Newborn 3 months 30-40bpm 3 months to 2 years 20bpm 2 years adult 12bpm EXCEPTION disease process involving air trapping

8 Proximal Airway Flow Monitoring

9 What is measured and where? Pressure- is measured back at machine Time is measured back at machine Flow is measured at patient (only with flow probe in place) Volumes (Vti and Vte) are derived from flows read at patient wye via flow sensor (deriving volumes from flow signals is a process called integration)

10 Proximal Airway Monitoring Hotwire flow sensor is required in order to run ventilator properly in Neonatal Mode Provides accurate two-way flow monitoring at patient s airway Critical for volume measurements on VLBW neonates

11 Heated Anemometers (flow sensor) How Do They Work? Heated element (gold wire) Measures the current necessary to maintain the temperature constant (cooling effect of gas flow) Lack of moving parts Fast and sensitive response (Electrical signal response slightly under speed of light) Virtually no resistance Very Accurate + -

12 Flow Sensor Issues Humidity Water will create significant fluctuations of accuracy. Secretions- surfactant Reading above or below baseline in the presence of zero flow Very delicate-breaks easily Wears-out due to processing and age

13 Calibration of Heated Wire Flow Sensor Occasionally RTs will need to disconnect flow sensor from the patient and perform zero flow calibration maneuver in order to reset flow reading to baseline.

14 Scalar Identification and Analysis PIP Pressure 0 + _ PEEP Flow Insp. Exp. Volume Insp. Exp.

15 Waveform Identification and Analysis Pressure 0 + _ PIP PEEP Flow Red indicates machine initiated breath Insp. Exp. Insp. Exp. Flow Baseline

16 SIMV with Spontaneous Pressure Supported Breaths Yellow indicates patient triggered breath

17 Synchronized Intermittent Ventilation (SIMV) Paw Are there any SIMV: Mandatory (patient or machine init spontaneous breaths Spontaneous breaths here? Paw

18 Pressure Support Ventilation Paw CPAP Paw PS

19 Increased Expiratory Resistance Prolonged expiratory flow indicates an obstruction to exhalation and may be caused by obstruction of a large airway, bronchospasm, or secretions

20 Increased Expiratory Resistance Normal Resistance Increased Resistance Possible Intrathoracic Obstruction- i.e. bronchospasm or secretions

21 Variable Airway Obstruction- Secretions or water in tubing (extra-thoracic) Jagged flow signal on inspiration

22 Airway Obstruction- Flow-Volume Loop before and after removing water from tubing BEFORE SXN AFTER SXN BE

23 Insufficient Expiratory Time Expiratory flow is unable to return to baseline prior to the initiation of the next mechanical breath Incomplete exhalation causes gas trapping, dynamic hyper-expansion and the development of intrinsic PEEP (aka Auto-PEEP or Breath-stacking ) Can be fixed by decreasing I-time

24 Gas Trapping with Inappropriate Inspiratory Time-Insufficient Exp.Time Inspiratory Time 0.5 s Inspiration beginning before flow returns to baseline Inspiratory Time 0.3 s Plenty of time to exhale at this I-Time

25 Air leaks

26 Air leak- Related to ET tubes or circuit Volume Volume Time Flow Volume Pressure never returns to baseline

27 Air leak- Related to ET tubes or Circuit Volume Volume Time Flow

28 Sawtooth" Pattern

29 Baseline Flow

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31 Patient Lockout

32 Trigger Sensitivity- Inappropriate Flow Trigger e Flow Sensitivity level Look at all this unsupported patient effort Time Time

33 Trigger Sensitivity- Appropriate Flow Trigger

34 Auto Cycling

35 Autocycling- Secondary to Leak

36 Resolved Autocycle- Flow Trigger Increased A short expiratory hold maneuver revealed no patient effort Trigger d to 0.7 L/M -auto cycle ended

37 Flow Starvation

38 Insufficient PSV Figure 8 Kuehne Just a 2011 little more pressure (indirectly increasing flow) and flow starvation goes away

39 Pressure Volume Loops to Assess RDS

40 Graphical Analysis of RDS Pre Surfactant

41 Pressure- Volume Graphical Analysis of RDS Six Hours Post Surfactant Nice football 45 angle