Mechanical Ventilation vr1 copy.pptx

MECHANICAL VENTILATION
Erwin M. Miranda
2nd Yr IM resident
Add a little bit of body text
Dr. Maria Lourdes Nocum
Pulmonologist

Objectives:
• To present the indications of mechanical
ventilation
• To discuss the following:
- Types of mechanical ventilation
- Modes of ventilation
- Complications of mechanical ventilation
- Weaning from mechanical ventilation

Mechanical Ventilation
• used to assist or replace spontaneous breathing
• achieved through the application of high-oxygen-
content gas and positive pressure
• The primary indication for initiation of MV is
respiratory failure
Harrisons Manual of Internal Medicine 20th ed

RESPIRATORY FAILURE
MECHANICAL VENTILATION:
• arterial O2 saturation (Sao2 )
<90%
• ventilation-perfusion mismatch
• intrapulmonary shunt
HYPOXEMIC
RESPIRATORY
FAILURE
S
C
I
E
N
C
E
C
L
A
S
S
O
L
D
M
E
A
D
S
E
C
O
N
D
A
R
Y
S
C
H
O
O
L
• elevated arterial carbon dioxide
partial pressure (PCO2 ) values
(usually >50 mmHg).
.
HYPERCARBIC
RESPIRATORY
FAILURE

TYPES OF MECHANICAL VENTILATION
• two basic methods of MV
• noninvasive ventilation (NIV) and
• invasive (or conventional mechanical) ventilation
(MV).

• noninvasive ventilation (NIV)
• effective in certain conditions, such as acute or
chronic respiratory failure
• associated with fewer complications—namely,
pneumonia and tracheolaryngeal trauma

• tight fitting face mask
• nasal cannula
• helmet/ hood

• Noninvasive ventilation (NIV)
-also used in patients with sleep apnea, respiratory
failure sec to COPD in acute exacerbations
-modes used are BIPAP and PSV
-patient intolerance, physical and psycholigical
discomfort

-Several randomized trials have shown that, in
patients with ventilatory failure characterized by blood
pH levels between 7.25 and 7.35, NIV is associated
with low failure rates (15–20%) and good outcomes

• Invasive ventilation/ conventional
-implemented once a cuffed tube is inserted into the
trachea to allow conditioned gas
-basic goals of MV are to optimize oxygenation
while avoiding ventilator-induced lung injury due to
overstretch and collapse/re-recruitment
-known as the “protective ventilatory strategy"

• Mode refers to the manner in which ventilator breaths are
triggered, cycled, and limited
• Trigger, either an inspiratory effort or a timebased signal,
defines what the ventilator senses to initiate an assisted
breath
• Cycle refers to the factors that determine the end of
inspiration.
• Limiting factors are operator-specified values, such as
airway pressure, that are monitored by transducers internal
to the ventilator circuit throughout the respiratory cycle
MODES OF VENTILATION

• Assist-Control Ventilation
-most widely used mode of ventilation
-commonly used for initiation of MV because it
ensures a backup minute ventilation in the absence of
an intact respiratory drive
-an inspiratory cycle is initiated either by the
patient’s inspiratory effort or, if none is detected
within a specified time window

• Intermittent Mandatory Ventilation
-operator sets the number of mandatory breaths of
fixed volume to be delivered by the ventilator
-synchronized mode (SIMV), mandatory breaths
are delivered in synchrony with the patient’s
inspiratory efforts at a frequency determined by
the operator.

• Intermittent Mandatory Ventilation
-If the patient fails to initiate a breath, the ventilator
delivers a fixed-tidal-volume breath
-SIMV allows patients with an intact respiratory
drive to exercise inspiratory muscles between
assisted breaths; thus it is useful for both
supporting and weaning intubated patients

• Pressure-Support Ventilation
-differs from the other two modes in that the operator sets the
pressure level (rather than the volume) to augment every
spontaneous respiratory effort
-PSV is often used in combination with SIMV to ensure
volume-cycled backup for patients whose respiratory drive is
depressed
-is well tolerated by most patients who are being weaned from
MV Harrisons Manual of Internal Medicine 20th ed

PRESSURE-CONTROL VENTILATION (PCV
- a specified pressure is imposed at the airway opening
throughout inspiration
- is the preferred mode of ventilation for patients in
whom it is desirable to regulate peak airway pressures,
such as those with preexisting barotrauma, and for
post– thoracic surgery patients
• Other Modes of Ventilation

INVERSE-RATIO VENTILATION (IRV)
- is a variant of PCV that incorporates the use of a
prolonged inspiratory time with the appropriate
shortening of the expiratory time
- has been used in patients with severe hypoxemic
respiratory failure

CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP)
- all ventilation occurs through the patient’s spontaneous
efforts
- ventilator provides fresh gas to the breathing circuit
with each inspiration and sets the circuit to a constant,
operator-specified pressure
- used to assess extubation potential in patients who
have been effectively weaned

PROTECTIVE VENTILATORY STRATEGY
Protective ventilation (purple shaded
area), using a lower tidal volume (6
mL/kg of ideal body weight) and
maintaining positive endexpiratory
pressure to prevent overstretching and
collapse/opening of alveoli,

PROTECTIVE VENTILATORY STRATEGY
(1) Set a target tidal volume close to 6 mL/kg of ideal
body weight
(2) Prevent plateau pressure (static pressure in the
airway at the end of inspiration) exceeding 30 cm H2
O.
(3) Use the lowest possible fraction of inspired oxygen
(Fio2 ) to keep the Sao2 at ≥90%.
(4) Adjust the PEEP to maintain alveolar patency while
preventing overdistention and closure/reopening.

COMPLICATIONS OF MECHANICAL VENTILATION
Pulmonary complications
• Barotrauma and volutrauma overdistend and
disrupt lung tissue
• pneumomediastinum,
• interstitial and subcutaneous emphysema
• pneumothorax

COMPLICATIONS OF MECHANICAL VENTILATION
Pulmonary complications
• nosocomial pneumonia, oxygen toxicity,
tracheal stenosis, and deconditioning of
respiratory muscles

(1) Lung injury is stable or resolving
(2) Gas exchange is adequate, with low PEEP (<8
cmH2 O) and Fio2 (<0.5)
(3) hemodynamic variables are stable, and the
patient is no longer receiving vasopressors; and
(4) the patient is capable of initiating spontaneous
breath
WEANING FROM MECHANICAL VENTILATION
Indicators for Weaning

(1) Daily wean screen
(2) Spontaneous Breathing Trial
-implemented with a T-piece using 1–5 cmH2 O
CPAP with 5–7 cmH2 O or PSV
(3) Assess if the patient able to protect the airway,
is able to cough and clear secretions, and is alert
enough to follow commands
(4) Evaluate using a “cuff-leak” test
ISteps for Weaning

Mechanical Ventilation vr1 copy.pptx

Mechanical Ventilation vr1 copy.pptx

Recommended

Recommended

More Related Content

Similar to Mechanical Ventilation vr1 copy.pptx

Similar to Mechanical Ventilation vr1 copy.pptx (20)

Recently uploaded

Recently uploaded (20)

Mechanical Ventilation vr1 copy.pptx