CPAP (RPA) - Intensive Care & Coordination Monitoring Unit

INTENSIVE CARE SERVICE
NURSING POLICY& PROCEDURES
NAME OF POLICY: CONTINUOUS POSITIVE AIRWAY PRESSURE
VENTILATION (CPAP)
GOAL: TO IMPROVE VENTILATION AND OXYGENATION BY
REDUCING PATIENT’S RESPIRATORY EFFORT AND
OXYGEN CONSUMPTION
Introduction:
Continuous positive airway pressure (CPAP) is a form of Non Invasive Ventilation (NIV) which
provides positive pressure throughout the respiratory cycle (ie on inhalation and exhalation) to
the spontaneous breathing patient who has sufficient respiratory drive and muscle strength. NIV
CPAP may be delivered either by dedicated CPAP unit or through a ventilator with NIV
functionality (CPAP may also be used on intubated patients via the ventilator).
A supply of gas provides the positive pressure and a restrictive valve placed within the circuit
provides PEEP. This delivers a pressure above atmospheric through the entire respiratory cycle.
This positive pressure improves oxygenation and lung compliance and reduces the work of
breathing (WOB) by:
• Enabling the patient to take larger tidal volumes (Vt) for the same amount of effort
• Increasing Functional Residual Capacity (FRC) ie preventing alveolar collapse and
recruiting already collapsed alveoli, there by increasing the surface area for oxygen
exchange to occur
• Reducing ventilation/perfusion (V/Q) mismatch (this occurs when blood flow passes
collapsed alveoli were gas exchange does not occur and so the blood returns to the
heart unoxygenated)
• During respiratory distress, oxygen demand increases resulting in worsening hypoxia
and further respiratory distress. As CPAP improves oxygenation the WOB is
decreased as the supply of oxygen meets the demand for oxygen.
A CPAP circuit must contain a flow regulator, an oxygen blender, reservoir bag under pressure
(2-3 times patient’s minute volume), humidifier, CPAP mask with strap and PEEP valve. The
gas supply must be greater than the patient’s minute volume to allow for any increase in
inspiratory effort. If the patient generates a large negative pressure the effects of CPAP will be
lost if the reservoir is not sufficient.
The airway pressure of CPAP applied to the thoracic cavity can reduce preload, resulting in
decreased pulmonary congestion, decrease cardiac output, blood pressure and may increase
intracranial pressure. It can also cause barotrauma, including alveolar damage, pneumothorax,
pneumomediastinum and subcutaneous emphysema. CPAP should be used with caution in
patients with chronic airways limitation disease (CAL) as they may have preexisting increased
FRC and this can cause alveolar distension and rupture. CPAP circuit should always be
humidified to reduce the drying effects of high-flow gases.
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INDICATIONS FOR CPAP:
• Acute respiratory failure
• Pulmonary contusion and flail chest
• Cardiogenic pulmonary oedema
• Asthma
• Chronic airways disease
• Post-operative atelectasis
• Obstructive sleep apnoea
• Pneumonia
CONTRAINDICATIONS:
• Unstable facial fractures
• Extensive facial lacerations
• Laryngeal trauma
• Recent tracheal or oesophageal
anastomosis
• Basal skull fracture, (use with caution)
• Patients at risk of GIT bleeds/ileus
USE WITH CAUTION
• Patients with recent GI surgery
• Decreased level of consciousness
EQUIPMENT:
Drager CPAP machine/Drager Ventilator with NIV function
Ventilation tubing for wet circuit (humidification base in tubing pack)
Sterile water bag
CPAP mask and head strap
PEEP valve (5,7.5, 10 or 12.5, may start with 10cmH20)
Bacterial/viral filter (machine side of tubing)
Test lung
White rubber connector (for dedicated Drager CPAP unit only)
CPAP MACHINE
SET UP:
See pictures below for assistance
• Keep “Y” connector attached to ventilator tubing
• Remove white side of vent tubing
• Place bacterial/viral filter to CPAP machine, then attach short arm of blue tubing from filter
to humidification bath
• Attach long arm of blue tubing from humidification bath to CPAP mask
• Assemble blue wire of humidification bath holder to blue tubing
• Using white rubber connector attach PEEP valve to exposed end of “Y” connector
• Perform safety valve check (see below)
• Adjust prescribed Fi02 (use flow rate of 40L/min)
Equipment for Designated CPAP circuit
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Entire designated CPAP circuit
PARAMETER SETTING:
• Medical orders are prescribed (Fi02, PEEP level and flow rate)
• Inform patient and relatives of the procedure and management (see nursing care)
• Usually the flow rate is 40L/min (see below for additional information)
• Use the table on the front of the machine to set the oxygen and air flow rates to obtain the
required flow rate and FI02 by turning the oxygen and air “black knobs”
• Check the level of PEEP on the pressure gauge of the CPAP machine to ensure the correct
level is being delivered once insitu to patient’s face
• Ensure CPAP mask is air tight as possible to obtain the desired CPAP level
Flow rate: A flow rate of 30-40L/min is the usual rate required. This roughly corresponds to
about 1.5times the usual minute volume. This flow rate should ensure an ample reservoir of gas
from which to breathe, however higher gas flows may be required in patients who are
tachypnoeic and those able to generate a large negative pressure through the circuit.
PEEP: PEEP is ordered in cmH20, the Drager pressure gauge measures in millibars, there is a
difference of approximately 2 units between millibars and cmH20. Therefore, there will be a
difference between what is ordered and what the Drager gauge measures
SAFETY VALVE CHECK:
• Set flow rate at approximately 20L/min (use 20L/min only for testing)
• Place test lung on patient end of the circuit and occlude PEEP valve
• Ensure the bellows expand to their full length
• The pressure indicated on the pressure gauge must not exceed 30mbars
• The safety valve at the rear will release air audibly
• Ensure this check is recorded in log book
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DRAGER XL & EVITA VENTILATORS:
SETUP:
see picture below for assistance
• Keep humidifying ventilation circuit intact
• Attach bacterial/viral filters to both inspiratory and expiratory arms of ventilator
• Attach short arm of blue tubing to filter on inspiratory side of ventilator and other end to
humidification bath
• Attach long arm of blue tubing from humidification bath to CPAP mask
• Assemble “blue” wire of the humidification bath holder, to blue tubing
• Attach white tubing to filter on expiratory side of ventilator, attach “yellow” wire of the
humidification bath holder to white tubing
• Attach “Y” piece to mask
• When ventilator is in “Stand By” select “Mask” and confirm. If using the EVITA ventilator
(not all EVITA’s can do NIV, check for sticker to indicate) the screen will change from blue
to green and the top right corner will state that the ventilator is in Non Invasive mode. If
using the XL ventilator touch the “Tube/mask” tab and select “ Mask” the words “Mask
Ventilation” should appear in the top right corner in orange
• Check ventilator as per invasive ventilation
• Touch the PEEP dials until desired parameter is reached and confirm
• Attach mask to patient
Setup of CPAP on Drager XL ventilator
(Same set up for Drager ventilators with NIV function)
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NURSING RESPONSIBILITIES:
• Explain to patient and relatives regarding the compliance to the mask as well as:
o It may be uncomfortable
o Difficulty in breathing out
o Tightness of the mask
o Feeling of “locked in”
o Possible eye swelling
• Second hourly mouth and pressure relief care (whenever possible)
• Padding may be required as the mask are not individualised
• Regular check of equipment, as there is no integrated monitoring facilities
• Hourly observations and recordings (monitor water level)
• Monitor airway and respiratory function (If patient is in difficulty inform Dr.)
• Monitor ABG’s
• Consult with medical officer for the need of a nasogastric tube to prevent gastric distention
and vomiting
• Be aware of CPAP complications (see below)
• Change tubing weekly and perform safety valve check
• Be aware of CPAP complications (see below)
COMPLICATIONS:
Complication Treatment Rationale
Skin necrosis (nose Apply soft dressing Cushions and protects the
and chin)
area
Gastric insufflation Placement of nasogastric tube Relives abdominal
and aspiration
distension
Mask intolerance and Select appropriate mask size Provides better seal and
leaks
comfort and prevents gas
from escaping
Transient hypoxia Provide alternative O2 source eg Reduces hypoxia and can
nasal prongs when eating and replace mask quickly if
closely monitor patient
removed
Hypotension Ensure patient is adequately Reduces the effects of
filled. Keep PEEP less than 8cm
H20 if possible.
increased thoracic pressure
CO2 rebreathing Ensure minimal dead space is Reduces resistance in the
present and appropriate expiratory circuit and allow CO2 to
valve is used
escape
Barotrauma Assess airway pressures and Prevents over expansion of
lungs
Nasal congestion and Ensure adequacy of humidified air Prevents build up and
sinusitis
increased viscosity of
secretions
Eye irritation and Avoid mask leaks, apply eye Reduced air flow into the
conjunctivitis drops as appropriate
eyes.
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DISPOSAL OF EQUIPMENT:
• CPAP machine is wiped down with mild detergent
• The ventilation tubing, PEEP valve and humidifier chamber are disposable
• All rubber connectors, hard plastic connectors and heating wires are sent to CSSD for
sterilisation
• CPAP mask and straps are cleaned with mild detergent
REFERENCES:
Bucher,L & Melander,S. (1999) Critical care nursing. W.B Saunders:Philadelphia
Hill, N.S. (1997). Complications of non-invasive positive pressure ventilation. Respiratory Care, 42 (4) 433-441.
Hotchkiss, J.R. & Marini, J.J. (1998). Non-invasive ventilation: An emerging supportive technique for the
emergency department. Annals of Emergency Medicine, 32 (4) 470-479.
Kannan, S. (1999). Practical issues in non-invasive positive pressure ventilation. Care of the Critically Ill, 15 (3)
76-79.
Knebel, A., Allen, M., McNemar, A. & Feigenbaum, K. (1997). A guide to non-invasive intermittent ventilatory
support. Heart & Lung, 26 (4) 307-316.
Mahamid, E. (2000). Non-invasive positive-pressure ventilation in acute respiratory failure. Care of the Critically
Ill, 16 (2). 55-58.
Marshall, A. & Pittard, M. Nursing the patient receiving Continuous Positive Airway Pressure Therapy. Australian
Nurses Journal, Clinical Update. February 1998.
Moore, M.J. & Schmidt, G.A. (2001). Keys to effective non-invasive ventilation, Part 1: Initial steps. Journal of
Critical Illness, 16 (2) 64-70.
Pierce, L.N.B. (1995). Guide to mechanical ventilation and intensive respiratory care. W.B. Saunders:
Philadelphia.
Py Ho, Rosa, & Boyle, M. (2000). Non-invasive positive pressure ventilation in acute respiratory failure: providing
competent care. Australian Critical Care, 13 (4) 135-143.
Oh, T. E. Intensive Care Mannual. Butterworths, 4 th ed. 2000.
“Vital Signs” product information, 1992
Occupational Health and Safety: Universal precautions taken in the preparation, administration of drug and
disposal of equipment and sharps.
Cross Referenced: RPAH Occ. Health & Safety Manual and Infection Control Manual
NSW Infection Control Policy 98/99
Revised by: Marianne O’Reilly CNS May 2003
Reviewed by: Chanelle Innes CNC Cheryl Richards CNE
Authorised by: Dr. Richard Totaro May 2003
Revision: May 2005
With the introduction of Powerchart online ordering, a clinical agreement has been set up with the Director
of ICS and other Staff Specialists. Nursing Management, with the agreement of the hospital executive, have
made arrangement that allows all permanently employed RPAH Nursing Staff to place orders for a variety of
tests on their behalf. It is a Health Insurance Commission (HIC) directive that all orders placed by nursing
staff are countersigned by the responsible MO within 14 days.
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