Transcript Mechanical Ventilatior

Mechanical Ventilatior
Outline:
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Definition.
Indications.
Types of ventilators.
Ventilator settings.
Modes of ventilation.
Risks.
Weaning .
Nursing care for ventilated patient.
Mechanical Ventilator
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A mechanical ventilator is a machine that
makes it easier for patients to breathe until
they are able to breathe completely on their
own. Sometimes the machine is called just a
ventilator, respirator or breathing machine.
Usually, a patient is connected to the
ventilator through a tube (called an
endotracheal tube) that is placed in the
windpipe.
Indications
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Physiologic reasons: include supporting
cardiopulmonary gas exchange
(alveolar ventilation &arterial
oxygenation) and reducing work
breathing , e.g pulmonary oedema ,
pnemonia.
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Clinical reasons include reversing
hypoxia &Acute respiratory acidosis
Acute respiratory acidosis with partial
pressure of carbon dioxide (pCO2) > 50
mmHg and pH < 7.25
Indications
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which may be due to paralysis of the diaphragm due
to Guillain-Barré syndrome, Myasthenia Gravis, spinal
cord injury, or the effect of anaesthetic and muscle
relaxant drugs
Increased work of breathing as evidenced by
significant tachypnea, retractions, and other physical
signs of respiratory distress
Hypoxemia with arterial partial pressure of oxygen
(PaO2) with supplemental fraction of inspired oxygen
(FiO2) < 55 mm Hg
Hypotension including sepsis, shock, congestive heart
failure
Initial ventilator settings
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tidal volume is calculated in milliliters
per kilogram. Traditionally 10 ml/kg was
used but has been shown to cause
barotrauma, or injury to the lung by
overextension, so 6 to 8 ml/kg is now
common practice in ICU. Hence a
patient weighing 70 kg would get a TV
of 420–480 ml.
Initial ventilator settings
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Initial FiO2
The FiO2 stands for fraction of inspired
oxygen, which means the percent of oxygen
in each breath that is inspired. (Note that
normal room air has ~21% oxygen content).
In adult patients who can tolerate higher
levels of oxygen for a period of time, the
initial FiO2 may be set at 100% until arterial
blood gases can document adequate
oxygenation.
Initial ventilator settings
Positive end-expiratory pressure
(PEEP)
It’s applying positive pressure at end of
expiration ,used with CV, A/C and SIMV.
It aims to prevent alveolar collapse &
Increase the surface of gas exchange.
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Initial ventilator settings
Respiratory Rate: number of breaths
the ventilator delivers per minute.
usual setting rate is 4-20breath/min.
 Sensitivity: determine the amount of
effort the patient must generate to
initiate ventilator breath.
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Modes of ventilation
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Controlled Mechanical Ventilation (CMV). In
this mode the ventilator provides a
mechanical breath on a preset timing. Patient
respiratory efforts are ignored. This is
generally uncomfortable for children and
adults who are conscious and is usually only
used in an unconscious patient. It may also
be used in infants who often quickly adapt
their breathing pattern to the ventilator
timing .
Modes of ventilation
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Synchronized Intermittent Mandatory Ventilation
(SIMV).
In this mode the ventilator provides a pre-set
mechanical breath (pressure or volume limited) every
specified number of seconds
Within that cycle time the ventilator waits for the
patient to initiate a breath using either a pressure or
flow sensor. When the ventilator senses the first
patient breathing attempt within the cycle, it delivers
the preset ventilator breath. If the patient fails to
initiate a breath, the ventilator delivers a mechanical
breath at the end of the breath cycle.
Modes of ventilation
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Assist Control (A/C( or continuous mandatory
ventilation : deliver gas at preset tidal volume
in response to patient’s inspiratory efforts &
will initiate breath if patient fails to do so
within preset time.
Modes of ventilation
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Continuous Positive Airway Pressure (CPAP).
A continuous level of elevated pressure is provided
through the patient circuit to maintain adequate
oxygenation, decrease the work of breathing, and
decrease the work of the heart (such as in left-sided
heart failure — CHF). Note that no cycling of
ventilator pressures occurs and the patient must
initiate all breaths. In addition, no additional pressure
above the CPAP pressure is provided during those
breaths. CPAP may be used invasively through an
endotracheal tube or tracheostomy or non-invasively
with a face mask or nasal prongs.
Risks:
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Infections - The endotracheal tube in the
windpipe makes it easier for bacteria to get
into the lungs. As a result, the lungs develop
an infection, which is called pneumonia. The
risk of pneumonia is about 1% for each day
spent on the ventilator. Pneumonia can often
be treated with antibiotics. Sometimes the
pneumonia can be severe or difficult to treat
because of resistant bacteria
Risks:
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Collapsed Lung - This is called a
pneumothorax. The mechanical ventilator
pushes air into the lungs. It is possible for a
part of the lung to get over-expanded which
can injure it. Air sacs may leak air into the
chest cavity and cause the lung to collapse. If
this air leak happens, doctors can place a
tube in the chest between the ribs to drain
out the air leaking from the lung.
Risks:
 Lung damage - When the lungs are
diseased and not functioning well, they
are at greater risk of injury. The
pressure to put air into the lungs with a
ventilator can be hard on the lungs.
Risks:
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Side Effects of Medications - Patients may
be given medications, called sedatives, to
make them more comfortable while the
ventilator pushes air in and out of the lungs.
These medications make patients sleepy and
help them forget unpleasant experiences. The
medications can build up in the body and the
patient may remain in a deep sleep for hours
to days, even after the medicine is stopped.
Weaning
Is the process of withdrawing the patient from
dependence on the ventilator.
 Begin during the daytime; allow the patient to
rest at night and between trails of weaning.
 Place the patient in an upright position.
 Causes of weaning failure include poor respiratory
or cardiac function ,infection, high metabolic demands,
poor nutrition and energy stores, and inadequate rest.
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Discontinue weaning if:
PH<7.3, PCO2>50torrs , PO2 <
60torrs.
The patient becomes anxious , fatigued.
Arrhythmias , homodynamic
deterioration.
Care of ventilated patient
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Provide care for patient’s artificial airway as needed.
Assess the patient’s peripheral circulation for
decreased cardiac output.
Be sure that ventilator alarms are on at all times .
Unless contra indicated turn the patient from side to
side every 2hours to facilitate lung expansion.
Place the call light within the patient’s reach.
Administer a sedative to relax the patient.
Covering and lubricating eyes.
Provide emotional support.