This study guide is loaded with helpful practice questions about Noninvasive Mechanical Ventilation. So if that’s why you’re here, then you’re definitely in the right place.
NIV, or noninvasive mechanical ventilation, is something Respiratory Therapists use and deal with on a daily basis. That it why it’s so important to learn and understand this information now, so that you can use it throughout your career.
So if you’re ready, let’s go ahead and get started.
What is Noninvasive Positive Pressure Ventilation?
Noninvasive Positive Pressure Ventilation (NPPV) is medical procedure that involves the use of ventilatory support without using an invasive artificial airway such as endotracheal tube or tracheostomy tube.
During NPPV, the health care provider administers air, usually with added oxygen, through a face mask or nasal mask under positive airway pressure (external lung pressure being greater than the pressure inside of the lungs).
What are the Goals and Benefits of Noninvasive Ventilation?
- Adequate ventilation and oxygenation
- Correction of respiratory failure
- Adequate patient tolerance and comfort
- Makes activities of daily living easier because it helps patients use more of their lung capacity while decreasing the breathing work load.
- Alleviates a wide array of symptoms such as daytime fatigue, morning headaches, breathing difficulties, and other symptoms associated with low oxygen levels.
- It reduces length of hospital stay by providing clients with adequate ventilation while preventing respiratory failure.
- It’s more convenient compared to invasive ventilation and it’s commonly given as in-home treatment as well.
- The treatment improves the patient’s quality of life by relieving symptoms associated with cardiopulmonary disorders.
Indications for NPPV:
- Acute respiratory failure
- Acute severe asthma
- Acute heart failure
- Breathing impairment due to a spinal cord injury
- COPD exacerbations
- Chest wall disorders
- Facilitation of extubation
- Moderate acidemia (pH <7.35)
- Moderate hypercarbia
- Neuromuscular disease
- Nocturnal hypoventilation
- Obesity hypoventilation syndrome
- Patients with breathing difficulties who are cooperative
- Prevention of reintubation in high-risk patients
- Restrictive thoracic diseases
Contraindications for NPPV:
- Agitation or lack of cooperation
- Cardiac arrest
- Excessive oral and nasal secretions
- Inability to fit the mask
- Inability to maintain a patent airway or protect the airway
- Recent surgical procedure involving the airway or gastrointestinal tract
- Respiratory arrest
Complications of Noninvasive Ventilation:
- Acute respiratory distress syndrome (ARDS)
- Aerophagia (excessive air swallowing)
- Airway dryness
- Decreased cardiac output
- Dry mouth
- Eye irritation from an air leak
- Gastric distension and insufflation
- Pressure areas from mask, tubing and strapping
- Secretion build up inside the mask
What are the Types of Noninvasive Positive Pressure Ventilation?
- BiPAP – this is a spontaneous breathing mode of noninvasive ventilatory support that allows for a separate regulation of the inspiratory and expiratory pressures.
- CPAP – this is a method of noninvasive ventilatory support where pressure above atmospheric maintained at the airway throughout breathing. The patient must be breathing spontaneously.
BiPAP vs CPAP
Both CPAP and BiPAP have similarities with regards to the attachments such as a mask and circuit, but they have a few key differences as well.
The purpose of CPAP is to improve and support the patient’s oxygenation. CPAP does not improve the patient’s ventilatory status, so the patient must be breathing spontaneously if CPAP is in use.
BiPAP, on the other hand, can help to improve the patient’s ventilatory status. So if the patient has an elevated PaCO2, BiPAP can be administered in order to help decrease the PaCO2 back into the normal range.
Interfaces for Noninvasive Positive Pressure Ventilation:
1. Mouthpiece – This is placed between the lips of the patient and is secured by lip-seal.
2. Nasal mask – It covers the nose but not the patient’s mouth.
3. Nasal pillows – It makes use of two soft silicone pillows that are inserted into the patient’s nostrils.
4. Oronasal mask – It covers both the mouth and nose of the patient.
5. Full-face mask – It covers the patient’s mouth, nose, and eyes.
So now that we’ve covered the basics of Noninvasive Positive Pressure Ventilation, now let’s dive deeper into some practice questions.
Noninvasive Ventilation Practice Questions:
1. What is CPAP?
A Constant pressure applied to the spontaneously breathing patient.
2. CPAP is applied via what?
A mask-type device.
3. CPAP does not do what?
It does not provide volume change or support in the patient’s minute ventilation.
4. What are some indications for CPAP?
It helps treat obstructive sleep apnea, it improves oxygenation.
5. What does NPPV stand for and what does it do?
NPPV stands for: Noninvasive Positive Pressure Ventilation. Pressure is applied intermittently with inspiration having a higher pressure than expiration.
6. What are the indications for NPPV?
Acute respiratory failure, and chronic respiratory failure.
7. What does NPPV provide?
It provides greater flexibility in the initiation and removal of mechanical ventilation.
8. What does NPPV permit?
Normal eating, drinking, and also communication with the patient.
9. What does NPPV preserve?
Airway defense, speech, and swallowing mechanisms.
10. NPPV avoids trauma associated with what?
Intubation, and the complications associated with artificial airways.
11. What does NPPV reduce the risk of?
VAP, ventilator-associated pneumonia.
12. NPPV also reduces the risk of what?
Ventilator-induced lung injuries associated with high ventilating pressures.
13. NPPV reduces muscle work and helps to what?
Avoid respiratory muscle fatigue that may lead to acute respiratory failure.
14. Does NPPV provide ventilator assistance with greater comfort, convenience, and less cost than invasive ventilation?
Yes, yes it does.
15. NPPV reduces the requirements of what?
16. NPPV reduces the need for what?
17. What does NIV stand for?
18. What are some contraindications of NIV?
Respiratory arrest (apnea) or the need for immediate intubation, unable to protect the airway, excessive secretions, hemodynamic instability, agitated and confused patients, paradoxical breathing, upper airway obstruction.
19. What are some other contraindications of NIV?
Facial deformities or conditions that could prevent a good mask fit, untreated pneumothorax, uncooperative of unmotivated patients, brain injury with unstable respiratory drive, major organ damage (severe hemorrhaging), recent GI surgery, irreversibility of
20. What are devices that can be used to provide NIV?
Nasal Masks, full face masks, nasal pillows, nasal cushions, total face mask.
21. When fitting the nasal mask you should choose?
The smallest mask without obstructing the nostrils.
22. Where are some anatomic leaks with the nasal mask?
Leaks can occur in the sides of
23. For the nasal mask, the top of the mask is placed just above what?
The junction of the nasal bone and the cartilage.
24. The nasal mask should not be pinching the nose where?
At the side.
25. The lower part of the nasal mask should fit just above what?
The upper lip.
26. A common error in fitting the nasal mask is what?
Choosing a mask that is too large.
27. What attaches to the end of the mask and rests on the forehead and helps reduce pressure on the bridge of the nose?
28. What are some advantages of nasal masks?
Less risk of aspiration, enhanced secretion clearance, less claustrophobia, easier speech, and less dead space.
29. What are some disadvantages of the nasal mask?
Mouth leak, less effectiveness with nasal obstruction, nasal irritation and rhinorrhea, and mouth dryness.
30. Full face masks are most often successful in which type of patient?
The critically ill patients.
31. The pressure
It allows a pressure manometer to measure pressure.
32. The ball and socket clip (escape clips) allows for what?
Easy mask removal.
33. A full face mask surrounds what?
The nose and mouth and rests below the lower lip.
34. What are the landmarks for a full mask?
Below the lower lip with the mouth open. Corners of the mouth. Just below the junction of nasal bone and cartilage.
35. Should the full face masks fit even if the patients mouth is slightly open?
Yes, yes it should.
36. You should be sure the mask fits well and does not leak excessively where?
Anywhere really, but particularly in the eyes.
37. Full face masks are most effective for?
38. What are some disadvantages of a full face mask?
39. Nasal pillows or nasal cushions are suitable for patients with what?
Claustrophobia, skin sensitivities, and the need for visibility.
40. How do you properly fit a nasal pillow or nasal cushion?
Use a plastic sizing gauge that is inserted in each nostril.
41. Some leaks may be caused by excessive tension of what?
The head straps.
41. In order to fit properly, headgear tension should allow?
1-2 fingers between the head straps and the face.
42. What should you use for patients without a full set of teeth?
Using a full face or total face mask can help minimize leaks.
43. What are the vented masks for?
They require a vent for exhalation and use only one corrugated tube to connect to the ventilator.
44. What is a characteristic about non-vented masks?
They have both an inspiratory and expiratory line. In a non-vented mask, the exhaled v
45. What are some complications associated with NIV?
Hemodynamic instability, r
46. What is the typical IPAP setting?
It is typically 8 – 12 cmH2O. It can be adjusted to change the tidal volume.
47. What is the typical EPAP setting?
It is usually started out at 4 cmH2O and can be increased in order to improve oxygenation.
48. What does the rise time do?
It determines how fast the vent rises from baseline pressure to target pressure.
49. The high and low-pressure alarm must be set to what in ST mode?
It should be set at +/- 5 in ST mode.
50. The low minute ventilation is usually set at what?
51. When will the apnea alarm sound?
When it does not recognize a spontaneous breath.
52. The tidal volume/minute ventilation is a running average of what?
The last 6 breaths.
53. What are the 9 goals of NIV in the acute care setting?
Improve gas exchange, avoid intubation, decrease mortality, decrease the length of time on the ventilator, decrease the length of hospital stay, decrease the chance of ventilator associated pneumonia, relieve respiratory distress symptoms, improve patient-ventilator sycnhrony, and maximize patient comfort.
54. Which therapies should be considered the first line of therapy in patients with exacerbated COPD?
55. What therapy should be tried first for a patient who has pulmonary edema from left heart failure?
56. Which NIV settings are adequate for a pt with cardiogenic pulmonary edema?
Mask CPAP at 8 – 12 cm H2Ocm and 100% FiO2.
57. What are some benefits of CPAP in postop abdominal surgery?
It lowers the chances of intubation, pneumonia, and infection/sepsis rates.
58. Which groups of patients are considered at risk for reintubation?
COPD, CHF, hypercapnia.
59. Which restrictive thoracic diseases are successfully managed with NIV?
(1) Post-polio syndrome, (2) Chest wall deformities, (3) Neuromuscular diseases, (4) Spinal cord injuries, and (5) Severe kyphoscoliosis.
60. How does NIV benefit patients with restrictive thoracic diseases?
It helps to rest inspiratory muscles, it helps by lowering CO2, and it improves the patient’s compliance, FRC, and deadspace.
61. Which groups of patients with nocturnal hypoventilation respond to NIV?
62. A patient is being ventilated with a nasal mask to relieve dyspnea. This patient has a long history of COPD/hypercarbia. What is the goal of NIV with regards to the ABGs of this patient?
Return the PaCo2 to less than 60 mmHg.
63. What are the 4 contraindications for NIV?
(4) Uncooperative patient, (2) Lack of financial resources, (3) Non-supportive family, and (4) Copious secretions.
64. What 2 interfaces are most commonly used to apply NIV in the acute care setting?
Nasal mask and the Full face mask.
65. Which of the following is a potential risk for overtightening the straps on the mask?
66. Which of the following interfaces is used in greater than 90% of patients with hypoventilation?
67. Which two interfaces appear to be more efficient to improve ventilation?
Nasal pillows and the full face mask.
68. Which interfaces that improve ventilation appears to be tolerated the best?
69. Which ventilators are not used for NIV?
70. What are 3 characteristics of most NIV ventilators?
(1) Microprocessor controlled, (2) blower driven, and (3) electrically powered.
71. What is the most important advantage of NIV over other types of ventilators?
It has the ability to trigger and cycle when small to moderate air leaks are present.
72. What are the required alarms for NIV?
Battery failure, circuit disconnect, and loss of power.
73. What strategy should be used when the patient complains of nasal congestion during the use of a nasal mask for NIV?
Add a heated humidifier.
74. Which is the current recommendation for adding humidity while using NIV?
Recommend it for long-term patients (longer than a day).
75. What defines the successful application of NIV?
Overall improvement of the patient’s ABG. You should be shooting for the PaO2 to increase and the PaCO2 to decrease.
76. What physiologic effect does raising the PEEP have on a patient receiving NIV?
An increased in FRC.
77. What is the best option for a patient in respiratory failure who continues to deteriorate 30 mins after the initiation of NIV?
Intubate and initiate mechanical ventilation.
78. What is the most common complication associated with NIV?
79. What is the recommended initial setting for ventilating pressure when delivering NIV in a pressure-triggered mode?
8 – 12 cm H20
80. What is the recommended initial setting for PEEP when delivering NIV in a pressure-triggered mode?
5 – 8 cmH2O
81. Initiating NIV can be done in which hospital settings?
Any acute care setting, the emergency department, the ICU, and of course, on the general floor.
82. What are the 3 modes commonly seen on NIV ventilators?
(1) CPAP, (2) Spontaneous (pressure support), and (3) timed (pressure assist/control).
83. What is required for noninvasive ventilators to work properly?
Continuous air leaks through one or more ports in the ventilator circuit or patient interface.
84. What mode of ventilation is most often used for NIV when a critical care ventilator is in use?
Pressure Support Ventilation (PSV)
85. What are the two levels of pressure on a BiPAP?
IPAP and EPAP
86. What is S/T mode on a BiPAP?
The patient determines the tidal volume. If the patient does not breath, the machine cycles to IPAP when
87. What do you set in CPAP mode?
The pressure is set on continuous. The patient breaths on their own and they are in control of their respiratory rate and tidal volume. You set the EPAP only.
88. List some indications for BiPAP?
Respiratory failure, post-surgical patients, hypoxemia due to hypoventilation, sleep apnea, ventilatory muscle fatigue, upper airway obstruction, and post-extubation difficulties.
89. List some contraindications for BiPAP?
Pre-existing pneumothorax, hypotension, pre-existing lung disease (i.e. emphysema), nose bleeding, aspiration, and sinusitis.
90. What are some side effects of BiPAP?
Pressure ulcers, claustophobia, and eye irritiation.
91. Why would you adjust IPAP?
For ventilation problems.
92. Why would you adjust EPAP?
For oxygenation problems.
93. What is the IPAP initial setting?
8 – 12 cmH20
94. What is the EPAP initial setting?
3 – 5 cmH20
95. What is the initial setting for oxygen on a BiPAP?
You should match the patient’s previous FiO2 or titrate to obtain an acceptable PaO2.
96. If there is an increase in the patient’s PaCO2, what should you do?
Adjust the IPAP in order to create greater pressure differences between IPAP and EPAP. This increases alveolar ventilation.
97. What would you do if the patient has hypoxemia?
Increase the level of EPAP.
98. What does the exhalation port do?
If directs air. The patient exhales through the port that they do not rebreath their CO2.
99. How should the mask fit?
From the bridge of the nose to just below the nares. Make sure the mask rests above the upper lip.
100. For a CPAP machine, describe the pressure?
It will be constant during inhalation and exhalation.
101. Which mask likely improves the tidal volume the most?
Full face mask
102. What is EPAP and how does it help with sleep apnea?
It is the same as CPAP and can be used to improve oxygenation or prevent airway closure in obstructive sleep apnea.
103. What is IPAP and how does it help with sleep apnea?
When this mode is set at a higher pressure than the EPAP, positive pressure will be applied during the inspiratory phase. This will maintain a patent airway in obstructive sleep apnea.
104. When using the timed mode of support for NPPV the patient cannot do what?
Trigger additional mandatory breaths
105. A patient with uncomplicated obstructive sleep apnea will generally find relief with EPAP pressures of what?
106. Patients with neuromuscular diseases will usually do well with inspiratory pressures of what?
107. A maximum pressure of 15 – 22 cmH2O may be necessary to achieve adequate?
Alveolar gas exchange
108. During respiratory support, oxygen must be titrated into the mask to achieve what?
109. What are the two levels of CPAP in BIPAP?
IPAP during inspiration, EPAP during exhalation. The IPAP (ventilation) should be greater than the EPAP (oxygenation).
They are flow triggered and require patient effort to be greater than 40 ml/sec to initiate an inspiration.
111. In BIPAP, what I
112. In BIPAP, what is the maximum inspiratory pressure?
22 cm H2O
113. During BIPAP the ventilator cannot provide adequate support for a patient with what?
High airway resistance or low lung compliance.
114. In BiPAP during operation, the IPAP is the inspiratory pressure needed to?
Abolish hypopnea and desaturation
115. In BiPAP during operation, what does the EPAP represent?
It is the expiratory pressure needed to keep the airway open.
116. When is BIPAP contraindicated?
On a patient with dysphagia.
117. If a patient receives NPPV for hypoxemic respiratory failure but does not show signs of improvement. How long should you wait to intubate?
No more than 1-2 hours. If the patient declines within the first 30 minutes, don’t wait any longer.
118. What 3 conditions are associated with hypoxemic respiratory failure qualify for NPPV as first line therapy?
Immunocompromised, those awaiting transplantation, and post lung resection.
119. What are 3 other indications for the use of NIV therapy in acute care?
(1) DNI orders, (2) to facilitate weaning for COPD and CHF, and (3) Post-op in abdominal surgeries.
120. What are 5 Restrictive Thoracic Diseases (RTD) for which NPPV is used in chronic care?
Post-polio, chest wall deformities, spinal injuries, severe kyphoscoliosis, and neuromuscular disease.
121. What are 3 benefits gained by NPPV in Restrictive Thoracic Diseases?
(1) Improved lung compliance, volume/FRC, and dead space, (2) Rest for the muscles of inspiration, and (3) lower PaCO2.
122. What 3 types of ventilators are used for NPPV?
Non-invasive Ventilator, Critical Care Ventilator, and Portable Volume Ventilator.
123. What are 4 disadvantages of a full face mask vs. a nasal mask?
(1) Increased dead space, (2) risk of aspiration, (3) claustrophobia, and (4) difficult to communicate.
124. What percent of acute respiratory failure patients should start with a full face mask?
125. What are the 5 patient Interfaces used with NPPV?
Nasal mask, full face mask, mouth piece, total face mask, and nasal pillows.
126. What is the exclusion criteria for NPPV in care of Acute Respiratory Failure?
Copious secretions, hemodynamic instability, apnea, face burns/trauma, and uncooperative patients.
127. What are the 4 ways NIV can be provided?
Negative Pressure Ventilator, Positive Pressure Ventilator, Rocking Bed, and a Pneumobelt.
128. How is NPPV typically administered?
Nasal or oral/nasal mask.
129. What condition must be present to add NPPV therapy with CPAP in Acute Pulmonary Edema?
Hypercarbia (ventilatory failure).
130. What are the 3 “constant” end expiratory pressures that support oxygenation and they all mean the same thing?
CPAP, EPAP, and PEEP.
131. What is the first line therapy for Acute Pulmonary Edema?
CPAP 8-12 cmH2O with 100% oxygen.
132. What is the standard of care in patients with acute COPD exacerbations?
NPPV (as an alternative to intubation and conventional mechanical ventilation).
133. What are the 5 goals of NPPV in the chronic care setting?
(1) Avoid the hospital, (2) increase survival, (3) relieve symptoms, (4) improve mobility, and (5) enhance life.
134. Which mode of ventilation re-establishes FRC and recruits alveoli?
EPAP (or CPAP or PEEP).
135. What 5 nocturnal hypoventilation signs must be seen for NPPV therapy to be considered for RTD?
Cognitive dysfunction, headache, fatigue, dyspnea, and daytime hypersomnolence.
136. A 21-year-old men who suffered a C4-5 subluxation injury to the spinal cord needs ventilatory support at night. The patient has skin breakdown at the bridge of his nose. Which of the following interfaces would you select?
137. A 57-year-old woman with a 45 pack-year smoking history and a barrel chest arrives in the emergency department complaining of shortness of breath. She is using pursed-lip breathing. Her arterial blood gas on a 2L/min nasal cannula is pH = 7.26 , PaCO2=64mmHg, PaO2=50mmHg, and HCO3=36mEq/L. Which of the following ventilators would you select?
138. A 67-year-old man had a surgical repair for a perforated gallbladder with peritonitis one week ago. He was extubated earlier in the day, but he presently has a respiratory rate of 32 breaths/min, is diaphoretic, and is using accessory muscles to breath. His ABGS on 60% O2 aerosol is pH= 7.40 PaCO2= 31mmHg PaO2= 71mmHg and HCO3= 19mEq/L. Which of the following action is most appropriate?
Intubate the patient if there is not significant improvement within 1 to 2 hours
139. After Mr. Pierre adjusts to the initial feel of NPPV, which of the following settings would you like to achieve?
IPAP= 10cm H2O, EPAP= 8cm H2O FiO2= 0.50
140. After Mr. Pierre is breathing for 10 minutes on his new NPPV settings, you see the following image on his ventilator graphics. Which of the following changes would you make?
Adjust the termination of flow.
141. All of the following types of patients could benefit from noninvasive positive-pressure ventilation except:
142. Mr. Pierre has been on his NPPV for the past 2 hours. His respiratory rate is 26 breaths/ min with moderate accessory muscle use. After viewing his arterial blood gas values on FiO2= 0.50, which of the following would you recommend?
Re-intubate and use invasive ventilation.
143. Noninvasive CPAP is indicated for which of the following?
Acute cardiogenic pulmonary edema with hypoxemia only.
144. The physician recommends a trial of noninvasive ventilation before reintubation. Which of the following ventilators would you plan to use?
Critical care ventilator.
145. Where would you set the initial IPAP and EPAP levels as you help Mr. Pierre adjust to the NPPV?
IPAP= 4cm H2O, EPAP= 2cm H2O
146. Which of the following actions will improve patient synchrony during NPPV?
Change the interface to reduce leaks.
147. Which of the following best describes the type of respiratory problem Mr. Pierre is likely experiencing?
Hypoxemia respiratory failure.
148. Which of the following practices would help your patient adjust to NPPV best?
Hold the mask in place with your hands until the patient adjusts to the gas flow.
149. Which of the following statements about noninvasive ventilators is true?
The inner lumen of the circuit must be completely smooth.
150. Which of the following statements about noninvasive ventilatory support is true?
The positive pressure in noninvasive positive-pressure ventilation inflates the patient’s lungs.
151. Which statement related to improving patient comfort with NPPV is correct?
A rise in pressure at the end of inspiration in a pressure-controlled breath indicates an increased work of breathing.
152. Which type of interface would you select for Mr. Pierre?
Total face mask.
153. How is noninvasive ventilation abbreviated?
NIV or NPPV.
154. The use of NIV has increased due to what?
Improved patient interfaces, improved quality of NIV ventilators, NIV software available for critical care ventilators, and reports of success in literature.
155. What is a key point of NIV?
It supports ventilation without an artificial airway.
156. What does NIV encompass?
Ventilation and CPAP — typically provided by a nasal or oral mask.
157. What is the primary indication for noninvasive ventilation?
Hypercapnic respiratory failure due to COPD. It is the standard of care for managing an acute exacerbation of COPD.
158. What other conditions benefit from NIV?
Asthma, acute cardiogenic pulmonary edema, and hypoxemic respiratory failure.
159. What other patients should NIV be considered for?
DNI (Do not intubate) patients, postoperative patients, patients in need of weaning facilitation (CHF and COPD patients), and those with nocturnal hypoventilation.
160. Why do we use NIV for hypercapnic respiratory failure due to COPD?
There is strong evidence in reducing the need for intubation, hospital mortality and length of stay.
161. What is hypoxemic respiratory failure?
The inability to maintain the normal oxygenation in the arterial blood. It may be indicated by a PaO2 of less that 60 mm Hg in an individual breathing supplemental oxygen.
162. What is Inspiratory Positive Airway Pressure (IPAP)?
Pressure that is applied during the inspiratory phase of mechanically assisted ventilation.
So there you have it! Now that you have gone through this study guide on Noninvasive Mechanical Ventilation, I hope you have a better understanding of BiPAP, CPAP, and everything else you need to know when it comes to NPPV.
I’m confident that you can use this information to help you pass your exams in Respiratory Therapy School. Not only that — this information will serve you well for the TMC Exam also, whenever that time comes.
Thank you so much for reading and as always, breathe easy my friend. 🙂
- Chang, David. Clinical Application of Mechanical Ventilation. 4th ed., Cengage Learning, 2013. [Link]
- Rrt, Cairo J. PhD. Pilbeam’s Mechanical Ventilation: Physiological and Clinical Applications. 7th ed., Mosby, 2019. [Link]
- Faarc, Kacmarek Robert PhD Rrt, et al. Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020. [Link]
- “Noninvasive Positive-Pressure Ventilation in Acute Respiratory Failure.” National Center for Biotechnology Information, U.S. National Library of Medicine, 6 Nov. 2007, www.ncbi.nlm.nih.gov/pmc/articles/PMC2043058.
- “Invasive and Non-Invasive Mechanical Ventilation.” PubMed Central (PMC), 1 June 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC7108446.
- “Indications and Practical Approach to Non-Invasive Ventilation in Acute Heart Failure.” National Center for Biotechnology Information, U.S. National Library of Medicine, 1 Jan. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC6251669.
Disclosure: The links to the textbooks are affiliate links which means, at no additional cost to you, we will earn a commission if you click through and make a purchase.