medicine 1st year

1. DR. BIKAL LAMICHHANE
INTERNAL MEDICINE
NAMS
NON INVASIVE VENTILATION

2. Noninvasive ventilation (NIV)
 Refers to the delivery of positive pressure ventilation through a noninvasive
interface (eg, nasal mask, face mask, or nasal plugs), rather than an
invasive interface (endotracheal tube, tracheostomy).
 Can be used as ventilatory support for patients with acute or chronic
respiratory failure.
 Major benefit of NIV over Invasive ventilation:
 Avoidance of intubation and the attendant risks of invasive mechanical
ventilation (decrease the incidence of nosocomial infections)
 Shorter length of stay and shorter duration of invasive monitoring
 Major disadvantages of NIV compared with invasive ventilation :
 Poorly tolerated in an awake patient
 Ventilation may be less effective due to air leaks
 Should only be used for short periods

3. Types of NIV:-
1. Ventillator type.
2. Interface mask type:-
1. Nasal mask
2. Oronasal Mask
3. Nasal prong mask
4. Full face mask

4. Oronasal mask –
 This interface includes the nose and mouth, but not the eyes and is
sometimes referred to as a face mask or orofacial mask.
 It is the mask that is most commonly used in patients with acute
respiratory failure for the delivery of NIV since they are reasonably
well tolerated and eliminate CO2 effectively, provided the mask fit is
good

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6.  Nasal mask –
 A nasal mask covers just the nose and may be an alternative in
those who do not tolerate an oronasal mask (eg, if the patient feels
an uncomfortable sense of pressure or suffocation).
 However, NIV delivered by a nasal mask may result in a large air
leak through the mouth and interfere with effective ventilation.
 For those who demonstrate an air leak that interferes with
ventilation a chin strap may alleviate the problem.

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8.  Nasal prongs –
 Nasal prongs (nasal pillows) are inserted into the nares and are an
option in patients who are intolerant of an oronasal or nasal mask.
 A chin strap is also often needed to minimize oral air leak

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11.  Full face mask –
 A full face mask includes the eyes, nose, and mouth.
 Although this mask is superior in terms of maximizing the NIV
delivered and minimizing air leaks, it often poorly tolerated.

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13.  The efficacy of different interfaces in patients with acute respiratory
failure has been examined .
 Three interfaces were compared in a trial that randomly assigned
26 patients with an acute exacerbation of chronic obstructive
pulmonary disease (AECOPD) complicated by hypercapnia to
receive NIV via full-face mask, nasal mask, or nasal prongs
(pillows) .
 Although the full face mask conferred the greatest physiologic
improvement, it was poorly tolerated. Nasal masks or plugs were
better tolerated.

14.  Mouth piece –
 Mouth pieces are devices that can be inserted into the mouth.
 However, air leak through the nose can occur unless nasal
pledgets are used.
 These are more commonly used in some patients with chronic
respiratory failure due to neuromuscular disorders, but they are
less practical for patients with acute respiratory failure.

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16.  Helmet –
 A helmet interface is also available for NIV .
 The helmet interface allows patients to talk, read, and drink through a straw, while minimizing
complications such as skin necrosis, gastric distension, and eye irritation .
 Mechanically, the helmet behaves as a reservoir between the ventilator and the patient.
 High flow and short inspiratory time are required to pressurize the helmet rapidly.
 The helmet may also be able to deliver higher levels of positive end-expiratory pressure
(PEEP) to improve oxygenation than high flow oxygen delivered via nasal cannulae (HFNC) ,
possibly making it more suitable in those who are PEEP-responsive.
 Drawbacks of the helmet device include the accumulation of CO2 within the helmet (alleviated
by increasing gas flow rates), a level of noise exposure sufficiently high to cause hearing
damage, more patient-ventilator asynchrony (due to delayed triggering and cycling), and less
relief of inspiratory effort

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18.  Ventilator circuit —
 Positive pressure and oxygen are delivered via tubing attached to the
interface.
 If a standard mechanical ventilator is used, then high flows up to an
FiO2 of 1 can be effectively delivered, provided air leaks are minimized.
 However, many portable ventilators can only deliver lower flow (eg, up to
10 or 15 liters of oxygen/minute, although higher flows may be feasible
with a helmet interface).
 Oxygen should be heated and humidified to improve tolerance and
prevent mucosal dryness

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22. Commonly used modes —
 Bilevel NIV (also known as bilevel positive airway pressure [BPAP])
 is the most commonly used mode of NIV in patients with acute respiratory failure.
 BPAP should not be confused with BiPAP; BiPAP refers to a device that provides positive pressure ventilation
including BPAP.
 BPAP is particularly helpful in patients with acute hypercapnic respiratory failure.
 This includes patients with
 acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and
 disorders associated with acute hypoventilation (eg, patients with drug overdose, patients with acute respiratory
failure associated with underlying neuromuscular disorders or obesity hypoventilation syndrome [OHS]).
 Bilevel NIV is also the most commonly used mode in patients with nonhypercapnic hypoxemic acute respiratory
failure due to conditions such as pneumonia, early acute respiratory distress syndrome, or asthma.
 Continuous positive airway pressure (CPAP)
 is most often indicated in patients with acute cardiogenic pulmonary edema but bilevel NIV is an appropriate
alternative especially when hypercapnia is present or if CPAP fails.
 Uncommon modes — Volume-limited modes and pressure support ventilation (PSV) may be delivered
noninvasively.

23. Selecting appropriate initial settings
 depends upon the mode selected to deliver NIV, resource availability, clinician and
staff expertise, and patient tolerance.
 •For patients in whom bilevel NIV (also known as bilevel positive airway pressure
[BPAP]) is chosen, typical initial settings include:-
 -BPAP mode in the spontaneous/timed (S/T) setting with a backup rate of 8 to 12
breaths/minute
 -Inspiratory positive airway pressure (IPAP) 8 to 12 cm H2O
 -Expiratory positive airway pressure (EPAP) 3 to 5 cm H2O
 -Fraction of inspired oxygen (FiO2) targeting peripheral O2 saturation (SpO2) >90 percent
 •For patients in whom continuous positive airway pressure (CPAP) is chosen,
typical initial settings include
 -CPAP at 5 to 8 cm H2O
 -FiO2 targeting SpO2 >90 percent

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25. Precautions:-
 NIV is typically administered in the upright or semi-upright position.
 Sedative and analgesic therapy that decreases respiratory drive may
be administered in small doses on an individualized basis when the
benefit of NIV tolerance is thought to outweigh the risk of worsening
respiratory failure.
 Enteral feeding is typically withheld,
 Bronchoscopy is technically feasible, but should be avoided unless
necessary.
 Nebulized medications, suctioning, circuit maintenance, and nursing
care can be performed in a similar fashion to that in patients who are
intubated.

26. Trial duration and re-assessment
 Most initial trials of NIV should target one to two hours, unless
the patient acutely deteriorates during that period.
 This time-frame is based upon trials in patients with acute
hypercapnic hypoxemic respiratory failure (mostly due to acute
exacerbations of chronic obstructive pulmonary disease
[AECOPD]).
 These data suggest that improvement of the pH and arterial
carbon dioxide tension (PaCO2) within 30 minutes to two hours
predicts continued success.

27.  Trial success — A trial is considered successful when both clinical
and gas exchange criteria are improved. In such cases, persisting
with NIV and monitoring for another two hours or more for
continued success is reasonable.
 Trial failure — If a patient does not improve, or deteriorates
following a one to two hour trial of NIV, the patient should be
considered to have failed NIV and be promptly intubated.
 Clinical criteria suggesting failure include worsening gas exchange,
increasing respiratory rate, worsening encephalopathy or agitation,
inability to clear secretions, inability to tolerate any of the interfaces,
or hemodynamic instability

28. Weaning —
 A patient is deemed ready to wean when gas exchange and clinical parameters
of acute respiratory failure have improved dramatically and the cause of
respiratory failure has improved.
 Physiologic parameters that support a readiness for weaning from NIV:-
 ●A respiratory rate ≥12 and ≤22 breaths per minute.
 ●Peripheral oxygen saturation (SpO2) ≥90 percent on ≤60 percent FiO2 or
predicted needs can be met with oxygen delivered via high flow nasal cannulae
(HFNC) or low flow oxygen.
 ●Hemodynamic stability (preferably off or on low dose vasopressors and heart
rate ≥50 and ≤120 beats per minute).
 ●The pH is preferably >7.25 and the patient should ideally be afebrile, awake
and alert, or easily arousable.
 ●Minimal NIV settings (eg, bilevel positive airway pressure 10 cm H2O/5 cm

29.  PATIENTS LIKELY TO BENEFIT:
 Acute exacerbations of chronic obstructive pulmonary disease
(AECOPD) that are complicated by hypercapnic acidosis (arterial
carbon dioxide tension [PaCO2] >45 mmHg [6 kPa] or pH <7.35
 Acute cardiogenic pulmonary edema (ACPE)

30. Acute exacerbation of chronic obstructive pulmonary disease
(AECOPD) with hypercapnic respiratory acidosis
 For patients with AECOPD complicated by hypercapnic (ie, respiratory) acidosis
(PaCO2 >45 mmHg [6 kPa] or pH <7.35), an initial trial of bilevel NIV (also known as
bilevel positive airway pressure [BPAP]).
 Almost 50 percent reduction in mortality
 65 percent reduction in the rate of intubation ,hospital length of stay, complications
unrelated to NIV (eg, ventilator-associated pneumonia, multiorgan failure), and
indices of gas exchange.
 Mechanism - improved alveolar ventilation as evidenced by improved respiratory
mechanics (eg, decreased respiratory rate, an increased tidal volume, and an
increased minute ventilation) and improved gas exchange parameters (eg, increase
in arterial oxygen tension [PaO2] and decrease in the PaCO2) .
 Mode of choice - Bilevel NIV .

31. Acute cardiogenic pulmonary edema
(ACPE)
 Mechanism : preload reduction, the prevention of alveolar collapse
at end expiration, and decreased left ventricular afterload.
 Trial of NIV, typically with CPAP.
 Decreases the need for intubation, improves clinical and laboratory
indices of respiratory failure (eg, heart rate, dyspnea, hypercapnia,
acidosis), and improves mortality.

32. PATIENTS LESS LIKELY TO BENEFIT
 Acute hypoxemic nonhypercapnic respiratory failure due to
conditions other than acute cardiogenic pulmonary edema (ACPE)
 Acute respiratory failure due to asthma exacerbation
 Post extubation, postoperative, or chest trauma-induced acute
respiratory failure
 Intubation refusal or palliation

33.  Acute nonhypercapnic respiratory failure due to AECOPD -
Benefit from bilevel NIV is uncertain.
 Pneumonia - Benefit is variable.
 Acute respiratory distress syndrome (ARDS) :
 Most patients require invasive mechanical ventilation.
 Bilevel NIV reserved for some patients with mild ARDS who is
hemodynamically stable, easily oxygenated, and has no
contraindications to its use.

34.  Postextubation respiratory failure — NIV has been used in
patients who develop acute respiratory failure in the first 24 to 72
hours following extubation.
 Postoperative respiratory failure — NIV has also been used to
treat patients who develop acute respiratory failure in the
postoperative setting.
 Chest trauma-induced respiratory failure — There is no specific
contraindication to NIV in patients who develop acute respiratory
failure following trauma to the chest.

35. CONTRAINDICATIONS

36. Complications:
 Local irritation or ulceration
 Air leaks
 Nasal dryness or congestion
 Gastric distension
 Aspiration

37. THANK YOU