- OXYGEN THERAPY AND NIPPV - Flashcards
Identify the indications for O2T
- hypoxia/hypoxaemia
- excessive WOB
- decreased SpO2
- excessive myocardial work
- decreased O2 carrying capacity (anaemia)
- peri-intubation
- MI
- Cardiac arrest
- shock
Identify the indications for use of paediatric high flow
oxygen devices in your unit
- Moderate to severe respiratory distress in infants (0-12 months) with bronchiolitis
who have failed to respond to low flow oxygen - ? about benefit for severe respiratory distress in children, unresponsive to other O2 therapies
- ?about benefit in use for bronchiolitis
Identify the contraindications for NIPPV
- Apnoea
- Cardiovascular instability
- High risk of aspiration
- Decreased GCS
- Claustrophobia / non compliant
- Secretions/vomiting
- Facial trauma
- Nasopharyngeal abnormalities
- Base of skull fractures
- Raised intracranial pressure (ICP)
- Pneumothorax (pre-ICC)
Discuss the potential complications of NIPPV
- Barotrauma
- Hypotension
- Altered conscious state
- Aspiration risk
- Gastric distension
- Decreased venous return from cerebral vessels
- Pressure sores
- Dry nose and eye irritation
- Conjunctivitis
- Discomfort
- Claustrophobia
- Poor sleep
Demonstrate competent
management of CPAP and/or
BiPAP therapy
. - Prepare patient (education + upright positioning)
- Inform NIC
- Check with attending Dr setting of limits (e.g. IPAP/EPAP)
- Check equipment, including suctioning
- Base line observations, ECG, gases
- Response (Monitor GCS, should not be commenced on a patient with ACS*)
- Airway (Monitor for patency, Look for secretions, Check equipment including suction)
- Breathing (Monitor RR / WOB / SpO2 / ABG, Assess speech pattern, Auscultate chest, Position – Fowlers, Repeated focussed respiratory assessment, all ventilator settings + documentation)
- Circulation (HR,BP,Cardiac monitor and ECGs, UO, can drop ITP and reduce venous return)
- Disability (1:1 nurse, monitor GCS, PAC, Temp, Nausea)
- Weaning
Discuss the concept of fraction of inspired oxygen (FiO2) and approximate values in low flow nasal prongs and hudson mask
RA: 0.21
NP: 1 - 0.24 2 - 0.28 3 - 0.32 4 - 0.36 5 - 0.40 6 - 0.44
HM:
5-10 - 0.4-0.6
Non-rebreather:
5-10 - 0.4-1.0
Discuss the purpose of reservoir oxygen systems
Reservoir systems are for the purpose of oxygen conservation. They store oxygen during exhalation and make that oxygen available for the beginning of the next inhalation (e.g. non-rebreather, BVM, and some nasal cannulae)
Identify the harmful effects of oxygen
CNS: seizures, tunnel vision, ringing in ears, nausea, twitching, irritability, dizziness
CVS: systemic vasoconstriction, increased venous return, increased BP, decreased HR, decreased CO, reduced coronary blood flow
RESP: increased RR, dry nose and mouth and increased susceptibility to mucus plugging, Haldane effect leads to decreased affinity of of Hb for CO2 and contributes to CO2 retention in COPD, cellular injury due to increased reactive oxygen species,
IMMUNE: increased risk of infection due to decreased efficacy of mucoscillary clearance
Discuss the ‘Venturi’ concept of air entrainment and high flow
A venturi adaptation to allow a specific percentage of FiO2 to be delivered to the pt through avoiding the entrainment of room air
Discuss the indications for high flow oxygen vs low flow
- Escalation therapy for all patients requiring more support than face mask oxygen
- Prevention of hypoxia or atelectasis following surgery or extubation (pressure support and can avoid mouth)
- Intubation aid (pre-oxygenation, intubate while on high flow)
- Facilitates weaning from respiratory support
- Alleviates dyspnoea and improves respiratory parameters in ED
Discuss the rationale for humidification and the correct temperature settings
- Emulates the natural balance of the heat and humidity of the lungs
- Protects the airway (prevents the desiccation of the airway epithelium, cilia cannot regrow from scarring/damage)
- Manages secretions (improves mucocilary clearance)
- Enables the comfortable delivery at high flows
- 37 degrees is optimal as it mimics the temperature and humidity of the lungs and allows for the asbove
Discuss the indications for NIV
- APO (cardiac)
- Sleep apnoea
- ARDS
- Trauma (flail chest)
- Pneumonia
- Chronic/acute respiratory failure
- Atelectasis
- Pancreatitis
- Carbon monoxide poisoning
- Asthma
Clinical manifestations:
- Elevated respiratory rate
- Difficulty breathing (dyspnoea)
- Increased WOB & Increased use of accessory muscles (tiring from other O2T)
- Decreased SpO2 usually less than 90% on high flow O2
- PaCO2 greater than 45mmHg (ABG/VBG)
- Acidosis (pH <7.35)
Define type 1 and type 2 respiratory failure and discuss the potential management of each with NIV
- Type I respiratory failure involves low oxygen, and normal or low carbon dioxide levels (failure in gas exchange, PaO2 <50)
- Type II respiratory failure involves low oxygen, with high carbon dioxide ( insufficiency of movement of air in and out of the lungs, PaO2>50 and pH<7.35
- Therefore, NIV assists easing the WOB and improving the efficacy of the movement of air in Type 1
- Type 2 respiratory failure can benefit from NIV in improving gas exchange (e.g. through maximising the surface area available for gas exchange)
Demonstrate the ventilator check and the correct settings for the set up of NIV
. - 100% FiO2
- PEEP - 5
- IPAP - 10 (always gap of 5)
- 30LPM (guided by pts MV)
Demonstrate knowledge of the modes used in NIV
CPAP (continuous positive airway pressure)
- Provides continuous positive airway pressure to a spontaneously breathing patient, applied throughout the respiratory cycle
- CPAP provides positive pressure at the end of expiration, preventing alveoli from collapsing
- CPAP can splint the airways open - reducing airway resistance and flow limitation
BiPAP (Bi-phasic positive airway pressure)
- Bi-PAP provides pressure support during inspiration and expiration at different levels.
- Inspiratory Positive Airway Pressure (IPAP) occurs when pt inhales → assists with the breath going in.
- Expiratory Positive Airway Pressure (EPAP) occurs when pt exhales → prevents the alveoli from collapsing
Describe how the ventilator can sense the patient initiaing a breath
.The ventilator notices the increase in pressure in the lungs
Demonstrate how the ventilator cycles from inspiration to expiration (and setting if adjustable on the ventilator)
Cycling is the threshold at which the ventilator will change from inspiration to expiration.
Threshold can be determined by:
- Pressure target
- Volume target
Define PEEP
- Positive end-expiratory pressure (PEEP) is the pressure in the lungs above atmospheric pressure that exists at the end of expiration
Demonstrate how to assess for gas leaks
- Feeling and listening around the mask and tubing
- Some air leak is OK, the carina will compensate
- Massive air leak will cause for ventilator to alarm “MV Low”, ““High leakage”
Discuss how to assess the efficiacy of the ventilator settings on commencement of both IPAP and EPAP
- decrease in RR, WOB
- Increase in SpO2 and PaO2
- Normalising of pH
Discuss the potential haemodynamic changes of a pt on NIPPV
.- Increased intrathoracic pressure causes a decrease in venous return
Discuss the need to perform ABGs and make changes based on the findings
- ABG is used to assess the effectiveness of NIV
- NIV should be improving the PaO2, PCO2 and the pH
- If not the patients physiological reponse should be monitered
- Settings should be assessed frequently and changed as needed dependant on the ABG response
Discuss when it is appropriate to remove the mask.
When pt has effective gas exchange on ‘normal settings’
e.g. FiO2 - 21%, EPAP - 5, IPAP - 10, Flow rate 30LPM
Discuss ways of improving compliance
- Appropriate education
- Mask fitting and comfort
- Start settings lower and work them up
Discuss indications for escalation of care of pt on NIV
- Pt physiological manifestations not improving
- ABG not improving
- should be assessed at 15 min/ 20 min and settings adjusted - an hour is too long
Discuss the initial ventilator setting for NIV
.100% FiO2 is a good starting point – benefit of 100% O2 outweighs the risk (End stage COPD – FiO2 can flip their respiratory drive)
Normal PEEP (2.5-5) from normal FRC 5-10 is a good start, if BP is lower start at lower end, if BP OK you can start at the top (10)
PEEP – 5 to start
BiPAP – Inspiratory pressure 10-15 to start
Flow rate - COPD pts can be up to 60LPM if not more dur to barrel chest and greater area to fill
