Intermittent Positive Pressure Breathing (IPPB): An Overview

Intermittent positive pressure breathing (IPPB) is a form of noninvasive ventilation (NIV) that delivers positive pressure during the inspiratory phase and allows passive exhalation back to atmospheric pressure.

It’s primarily used to assist patients who are unable to take deep breaths on their own, helping to expand the lungs and improve breathing efficiency.

IPPB therapy was developed to promote deeper inhalation, stimulate an effective cough, and treat or prevent atelectasis—a condition in which parts of the lung collapse and fail to properly inflate. In this article, we’ll break down how IPPB works and why it’s an important tool in respiratory care.

What is Intermittent Positive Pressure Breathing (IPPB)?

IPPB is a patient-triggered, pressure-cycled type of noninvasive ventilation that assists with lung expansion. It delivers machine-generated, pressure-supported breaths through a mouthpiece or mask, inflating the lungs more fully than spontaneous breathing alone.

This positive pressure:

• Enhances alveolar ventilation
• Promotes better oxygen and carbon dioxide exchange
• Improves lung compliance
• Reduces the work of breathing

IPPB is particularly useful for patients at risk of pulmonary complications, such as those recovering from surgery, experiencing neuromuscular weakness, or who are unable to perform incentive spirometry due to sedation or reduced consciousness.

By supporting lung expansion and secretion clearance, IPPB plays a key role in preventing postoperative atelectasis and other respiratory issues.

Indications for IPPB

Intermittent positive pressure breathing (IPPB) is primarily used as a lung expansion therapy to treat or prevent atelectasis. It is especially beneficial for postoperative patients who are sedated, unconscious, or otherwise unable to perform incentive spirometry.

Additional indications for IPPB include:

• Enhancing cough effectiveness
• Reducing the work of breathing
• Mobilizing retained secretions
• Delivering aerosolized bronchodilators
• Managing pulmonary edema

Positive outcomes of IPPB therapy may include:

• Improved breath sounds
• Increased oxygen saturation
• Enhanced vital capacity
• Clearer chest radiographs
• A stronger, more productive cough

Contraindications for IPPB

IPPB is not appropriate for patients with the following conditions:

• Untreated pneumothorax
• Active hemoptysis
• Pulmonary tuberculosis
• Pulmonary hemorrhage

Note: It should also be avoided in alert and cooperative postoperative patients who can perform sustained maximal inspiration (SMI) using incentive spirometry. In such cases, IS is the preferred and safer option.

What is Atelectasis?

Atelectasis refers to the collapse of alveoli, the tiny air sacs in the lungs where gas exchange takes place. It can range from a localized area in one lobe to a complete lung collapse.

When alveoli collapse, oxygen cannot enter and carbon dioxide cannot exit the bloodstream properly. This leads to impaired gas exchange, potentially resulting in hypoxemia, hypercapnia, and other serious respiratory complications.

IPPB helps by applying positive pressure to reopen collapsed alveoli, thereby restoring ventilation and preventing complications.

IPPB Settings and Adjustments

IPPB therapy allows clinicians to tailor the support delivered through key ventilator settings:

• Sensitivity: Determines how easily the patient can trigger a breath
• Flow rate: Affects how quickly air is delivered during inhalation
• Pressure: Sets the peak inspiratory pressure
• Air mix: Controls the oxygen concentration delivered

How to adjust IPPB settings:

• To increase tidal volume: Increase the pressure
• To decrease tidal volume: Decrease the pressure
• For faster breaths: Increase flow rate (decrease inspiratory time)
• For slower breaths: Decrease flow rate (increase inspiratory time)

Common IPPB Issue: Machine Won’t Cycle Off

This usually indicates a leak in the system. The ventilator won’t reach the preset pressure, preventing it from cycling off.

Troubleshooting tips:

• Inspect and tighten the circuit connections
• Ensure the patient maintains a tight lip seal around the mouthpiece
• Use a Bennett seal or an alternative mouth seal if needed

Proper adjustment of IPPB settings is essential to ensure effective and safe therapy tailored to each patient’s needs. By understanding how each control affects ventilation, clinicians can optimize lung expansion, enhance gas exchange, and minimize complications.

Regular monitoring and prompt troubleshooting help maintain consistent performance and therapeutic benefit throughout the session.

Steps for Administering IPPB

To ensure safe and effective delivery of IPPB therapy, it’s important to follow a structured process. Here is a step-by-step guide that outlines the proper procedure for administering IPPB, from preparation to post-treatment care.

1. Verify the physician’s order
2. Gather all equipment (IPPB machine, circuit, gas source, mouthpiece)
3. Explain the procedure to the patient clearly
4. Assess baseline vitals and breath sounds
5. Set initial parameters: sensitivity, flow, peak pressure
6. Add medication to the nebulizer if ordered
7. Test cycling by occluding the mouthpiece to ensure it shuts off correctly
8. Instruct the patient to seal lips around the mouthpiece and breathe only through the mouth
9. During inspiration, let the machine deliver a full breath, pause briefly at the end of inspiration, then exhale slowly
10. Adjust settings as needed to achieve a 1–2 second inspiratory time and 1:3 I:E ratio
11. Monitor the patient throughout the 10–15 minute session
12. After therapy, disconnect the system, discard any leftover medication, and store the patient’s circuit for future use

Note: By following these steps, clinicians can optimize the benefits of IPPB therapy while minimizing potential complications. Proper technique, ongoing patient monitoring, and appropriate adjustments are key to achieving the best therapeutic outcomes.

IPPB vs. Incentive Spirometry (IS)

Both IPPB and IS are used to prevent and treat atelectasis, but they function differently:

• Incentive spirometry relies on the patient’s voluntary effort to take deep breaths without positive pressure
• IPPB delivers positive pressure breaths passively, making it ideal for patients who are weak, sedated, or unresponsive

When to Choose Incentive Spirometry:

• The patient is alert, cooperative, and able to follow instructions
• There is a concern about barotrauma or pneumothorax from pressure ventilation

When to Choose IPPB:

• The patient is unable to perform IS effectively
• More consistent or deeper breaths are required to promote alveolar expansion

IPPB Practice Questions

1. What is intermittent positive pressure breathing (IPPB)?
IPPB is a form of active hyperinflation therapy that uses positive pressure greater than atmospheric during inspiration, followed by passive exhalation back to atmospheric pressure.

2. What is the primary purpose of IPPB therapy?
To augment lung expansion, deliver aerosolized medications, and assist with ventilation in spontaneously breathing patients.

3. How long does a typical IPPB treatment last?
IPPB is a short-term treatment, usually administered for no longer than 15 to 20 minutes per session.

4. How often is IPPB administered to non-critical patients?
Non-critical patients typically receive IPPB therapy either four times per day (QID) or twice per day (BID).

5. How frequently is IPPB administered to critically ill patients?
For critical patients, treatments may be administered as frequently as every 1 to 6 hours (q1–q6h), depending on clinical need.

6. In which clinical settings is IPPB commonly used?
IPPB is administered in hospitals, clinics, extended care facilities, and occasionally in home care settings.

7. Is IPPB considered the first-line therapy? Why or why not?
No, IPPB is not the first choice due to the availability of less costly and simpler alternatives such as metered-dose inhalers (MDIs) and small volume nebulizers (SVNs).

8. When should IPPB be considered?
IPPB should be considered when other methods fail to achieve the desired therapeutic response in a patient.

9. What are the key physiologic effects of IPPB therapy?
Positive intrathoracic pressure, mechanical bronchodilation, increased tidal volume, decreased work of breathing, decreased PaCO₂, improved ventilatory pattern, and enhanced secretion clearance.

10. What does positive pressure breathing accomplish?
It reverses the normal intrathoracic and intrapulmonary pressure relationship, promoting lung expansion.

11. What occurs during spontaneous ventilation?
Air enters the lungs due to a negative pressure gradient (-3 to -5 cmH₂O) between the mouth and alveoli, resulting in an inspiratory volume of approximately 300–700 mL per breath.

12. What is true about exhalation during spontaneous breathing?
Exhalation is passive and requires no muscular effort unless airway resistance or lung compliance is abnormal.

13. What happens to intrathoracic pressure during positive pressure ventilation?
It becomes more positive, especially during inspiration, which is the opposite of the pattern seen in spontaneous breathing.

14. What are the pressure changes during spontaneous breathing with IPPB?
Inspiration is sub-atmospheric (negative), and exhalation becomes positive due to pressure application.

15. What effect does IPPB have on normal inspiratory pressure gradients?
IPPB reverses the normal negative inspiratory pressure gradient by delivering positive pressure during inhalation.

16. How does positive intrathoracic pressure affect pulmonary circulation?
It reduces venous return and decreases overall thoracic blood volume, potentially affecting cardiac output.

17. Which patients are most affected by reduced venous return during IPPB?
Patients with cardiovascular disease or hypovolemia are most at risk from the effects of increased intrathoracic pressure.

18. What causes mechanical bronchodilation during IPPB therapy?
Positive pressure distends the tracheobronchial tree, decreasing airway resistance—especially when used with bronchodilators.

19. How can IPPB increase a patient’s tidal volume?
Properly applied IPPB can increase tidal volume by three to four times the patient’s baseline during treatment.

20. What must happen for IPPB pressure effects to effectively improve tidal volume?
The tidal volume delivered must be greater than that achieved during spontaneous breathing.

21. How does IPPB reduce the work of breathing (WOB)?
IPPB decreases WOB during therapy by aiding in alveolar recruitment and secretion clearance, but the effect is only sustained if therapy improves lung function.

22. What happens to PaCO₂ during effective IPPB therapy?
Improved alveolar ventilation may decrease PaCO₂, returning it to normal and potentially improving PaO₂.

23. What adverse effect can result from rapid changes in blood gases during IPPB?
Rapid blood gas changes can cause acute respiratory alkalemia, leading to dizziness, lightheadedness, anxiety, seizures, and arrhythmias.

24. How does IPPB help create a more efficient ventilatory pattern?
By adjusting the inspiratory to expiratory (I:E) ratio, IPPB can restore a more effective breathing rhythm.

25. How does properly administered IPPB assist with secretion removal?
Through increased tidal volume, mechanical bronchodilation, better gas distribution, breath-hold maneuvers, and effective coaching.

26. What is the minimum I:E ratio recommended during IPPB therapy?
A minimum ratio of 1:2 is recommended, though 1:3 or 1:4 is often more effective for optimal ventilation.

27. How do you identify appropriate candidates for IPPB therapy?
IPPB should only be administered to correct specific clinical abnormalities. The therapist must evaluate its necessity, compare it with alternative therapies, and ensure the treatment is administered correctly to be beneficial.

28. What are the prerequisites for ideal administration of IPPB?
A knowledgeable, well-trained respiratory therapist; a relaxed, cooperative patient; clearly defined therapeutic goals; proper instruction; and honest assessment of the therapy’s effectiveness.

29. What are the primary indications for initiating IPPB therapy?
Patients unable to breathe deeply or cough effectively, those with vital capacities <10 mL/kg of ideal body weight, or patients needing short-term ventilatory support or aerosol delivery.

30. Which conditions often require improved lung expansion with IPPB?
Conditions such as atelectasis, neuromuscular disorders, sedation, or post-abdominal or thoracic surgery, where deep breathing and inspiratory holds can help reopen collapsed alveoli.

31. How can IPPB help with mucostasis and secretion clearance?
IPPB improves cough effectiveness, promotes better gas distribution, and mechanically dilates airways to mobilize thick or obstructive secretions.

32. When is IPPB used for short-term ventilatory support?
In early stages of respiratory distress or during acute COPD exacerbations to prevent intubation and stabilize breathing.

33. What is the controversy surrounding the use of IPPB to deliver aerosol medication?
IPPB should be reserved for patients with severe bronchospasm or unstable conditions after failing simpler delivery methods like MDI or DPI.

34. What are the criteria for assessing the need for IPPB?
Presence of atelectasis, reduced pulmonary function (e.g., VC < 10 mL/kg IBW), neuromuscular impairment, bronchospasm, fatigue, or COPD with ineffective cough.

35. How is the effectiveness of IPPB therapy evaluated?
By observing increased tidal volumes (≥25%), improved FEV1 or peak flow, enhanced cough and secretion clearance, improved breath sounds or CXR, and favorable patient feedback.

36. What are the adverse pulmonary effects of positive pressure therapy?
Air trapping, auto-PEEP, alveolar overdistention, increased airway resistance, V/Q mismatch, barotrauma, and potential for pneumothorax.

37. What are the circulatory effects associated with IPPB therapy?
Decreased venous return, reduced cardiac output, hypotension, arrhythmias, coronary insufficiency, and increased intracranial pressure.

38. What gastrointestinal effects can occur with IPPB?
Gastric insufflation, abdominal distension, vomiting, risk of aspiration, and worsened postoperative abdominal pain.

39. How can IPPB therapy affect blood gases?
IPPB may cause hyperoxia (if oxygen is the source gas), hypocarbia (respiratory alkalemia), hypoventilation, or cerebral vasoconstriction with symptoms like dizziness and paresthesia.

40. What are the adverse effects of bronchodilator aerosols delivered with IPPB?
Increased V/Q mismatch, tachycardia, arrhythmias, tremors, nervousness, and tachyphylaxis (reduced drug response over time).

41. What are potential adverse effects from mucokinetic aerosols during IPPB?
Nausea, bronchial irritation, vomiting, and loosening of secretions with distal airway retention that may worsen oxygenation.

42. What are some general adverse reactions to IPPB therapy?
Claustrophobia, increased dyspnea, machine-patient asynchrony, nosocomial infections, and psychological dependence.

43. What are absolute contraindications to IPPB therapy?
Elevated intracranial pressure (>15 mmHg), recent facial/oral/skull surgery, hemodynamic instability, untreated TB, active hemoptysis, bullous lung disease, or a history of pneumothorax.

44. What infection control measures should be followed with IPPB?
Use standard precautions, disinfect reusable equipment, avoid rinsing nebulizers with tap water, and use sterile water for cleaning.

45. What are the major phases of administering IPPB therapy?
Preliminary planning, patient assessment, therapy implementation, and post-therapy evaluation.

46. What takes place during the preliminary planning stage of IPPB?
Therapy need is established, diagnostic outcomes are reviewed, and treatment goals are defined, explicit, and measurable.

47. What are the desired outcomes of IPPB therapy?
Increased inspiratory capacity, improved FEV1 or peak flow, enhanced cough, improved chest x-ray, better breath sounds, and positive patient response.

48. How would you define outcome goals in a post-op patient with suspected atelectasis?
Spontaneous inspiratory capacity >70% predicted, improved x-ray findings, reduced respiratory rate <25/min, and resolution of fine crackles.

49. What is included in the baseline assessment prior to IPPB?
Vital signs, respiratory rate and pattern, breath sounds, and general physical observation of the patient.

50. What are the steps in the implementation phase of IPPB?
Equipment preparation, patient orientation, proper positioning, initial therapy application, and adjusting pressure and flow parameters for optimal response.

51. What should be included in patient orientation before starting IPPB therapy?
The purpose of therapy, how it works, what the patient will feel, expected outcomes, and a brief demonstration of the equipment.

52. What are the recommended initial IPPB settings?
A sensitivity trigger of 1–2 cmH₂O, initial pressure between 10–15 cmH₂O, and a breathing pattern of approximately 6 breaths/min with an I:E ratio of 1:3 or 1:4.

53. How should parameters be adjusted during IPPB to meet therapeutic goals?
Set a tidal volume target of 10–15 mL/kg of ideal body weight or 30% of predicted inspiratory capacity, then increase pressure until that goal is achieved.

54. What should be assessed after IPPB therapy?
Vital signs, sensorium (mental status), breath sounds, and any change in patient condition.

55. What must be documented in the patient’s record after IPPB treatment?
Pre- and post-treatment assessments and any adverse reactions observed during the procedure.

56. What are common technical problems associated with IPPB machines?
Large negative swings during inspiration, failure of system pressure to rise, premature cycling, or failure to cycle off.

57. What is the “Triple S” rule for monitoring patient response during IPPB?
Stay with the patient, Stop the treatment if distress occurs, and Stabilize the patient if adverse signs develop.

58. What is IPPB in clinical terms?
The therapeutic application of inspiratory positive pressure to the airway of a spontaneously breathing patient to augment ventilation.

59. What are common clinical indications for IPPB therapy?
Atelectasis, increased work of breathing, ineffective cough, hypoventilation, pulmonary edema, increased airway resistance, and to aid ventilator weaning.

60. What are absolute and relative contraindications to IPPB therapy?
Untreated pneumothorax (absolute), tuberculosis, subcutaneous emphysema, hemoptysis, bullous lung disease, uncooperative patient, and recent head or facial surgery.

61. What additional contraindications should be considered before administering IPPB?
Hemodynamic instability, increased ICP, facial or esophageal trauma, tracheoesophageal fistula, and the availability of simpler, more cost-effective therapies.

62. What are potential complications of IPPB therapy?
Barotrauma, excessive oxygenation, hypotension, increased ICP, hemoptysis, gastric distension, nosocomial infections, and air trapping.

63. How can decreased cardiac output and increased ICP be avoided during IPPB?
Use an I:E ratio of at least 1:2 or 1:3 to allow sufficient expiratory time and venous return.

64. Why can IPPB contribute to pneumothorax in some patients?
It may direct ventilation into weak or damaged areas of the lungs, such as blebs, leading to rupture and pneumothorax.

65. What are signs and symptoms of pneumothorax during IPPB?
Sudden chest pain, shortness of breath, unilateral chest rise, increased respiratory and heart rate, and early cycling of the machine.

66. Why is excessive oxygenation a concern during IPPB?
Oxygen-powered machines may deliver high FiO₂, risking oxygen-induced hypoventilation in CO₂ retainers and increased air trapping.

67. How can IPPB therapy lead to increased intracranial pressure?
Elevated airway pressures can impede cerebral venous return, increasing ICP—especially in patients with head injuries or neurosurgery.

68. Why might hemoptysis occur during IPPB?
From ruptured vessels or tumors made worse by increased airway pressure and more forceful coughing.

69. How does gastric insufflation occur with IPPB?
Air may enter the stomach, especially when using a mask, or in unresponsive patients unable to protect the airway.

70. What are the infection risks associated with IPPB?
Improper equipment cleaning, use of tap water in nebulizers, and repeated use of contaminated devices can lead to nosocomial infections.

71. What steps ensure proper administration of IPPB?
Assemble equipment, verify orders, assess contraindications, identify the patient, position upright, place medication, and guide the patient through treatment.

72. What are the key considerations when setting machine parameters for IPPB?
Start with lower pressure and gradually increase. Adjust flow to maintain inspiratory time and ensure patient comfort.

73. What steps should be taken during IPPB treatment?
Check vitals mid-treatment, monitor patient response, have the patient cough after nebulization, and reassess vitals afterward.

74. What are important IPPB administration tips for effectiveness?
Tidal volume should exceed spontaneous effort, avoid excessive flows, minimize high pressures, and use proper I:E ratios.

75. What should an IPPB physician order include?
Therapy objectives, frequency, duration, and medication to be used.

76. What is a common starting pressure setting for IPPB?
10–15 cmH₂O.

77. What I:E ratio is typically used to begin IPPB therapy?
An I:E ratio of 1:2 or 1:3 to ensure adequate expiration.

78. How does IPPB inflate the lungs in patients unable to take deep breaths?
By applying positive pressure during inhalation and exhalation, enhancing lung expansion and tidal volume.

79. When is IPPB preferred over incentive spirometry?
When the patient cannot perform IS due to weakness, pain, or impaired consciousness.

80. What are five common contraindications for IPPB therapy?
Untreated pneumothorax, persistent hiccups, nausea and vomiting, active tuberculosis, and recent facial or cranial surgery.

81. What are two common complications of IPPB therapy?
Hyperventilation leading to respiratory alkalosis and gastric distention due to air swallowing.

82. During IPPB therapy, if system pressure suddenly rises at the end of inspiration, what should the patient be instructed to do?
“Exhale gently and normally”

83. If a patient has difficulty initiating breaths with an IPPB machine, what should the therapist adjust?
Sensitivity

84. Which control is used to increase the tidal volume delivered by an IPPB device?
Pressure limit

85. If the IPPB machine cycles on but fails to shut off, what is the most likely cause?
There is a leak in the system

86. Adjusting the flow rate on an IPPB machine affects which parameter?
Inspiratory time

87. What is the recommended starting flow rate for IPPB therapy?
Use the lowest tolerable flow rate to avoid hyperventilation while meeting the patient’s ventilatory needs.

88. What is the typical breathing rate during IPPB therapy?
7–10 breaths per minute

89. What is the usual inspiratory time (I-time) setting for IPPB?
2–4 seconds

90. How long should the patient hold their breath during IPPB?
2 seconds to allow for optimal gas exchange.

91. What is the expected expiratory time (E-time) during IPPB?
4–6 seconds to ensure complete exhalation

92. What is the required volume benchmark for IPPB therapy to be considered effective?
Tidal volume should be at least 25% greater than spontaneous VT and 10–15 mL/kg of body weight.

93. What are common clinical goals of IPPB therapy?
Improved breath sounds, sputum production, oxygenation, ABGs, PFT results, CXR, and subjective patient response.

94. What FiO₂ is delivered when the air-mix control is pulled out on the Bird Mark 7?
Approximately 40–60%

95. In pressure-cycled IPPB devices, what ends inspiration?
When the preset pressure is reached

96. How do you deliver 100% oxygen to a pulmonary edema patient on the Bird Mark 7?
Push the air-mix control in and administer with ethyl alcohol if ordered.

97. If the pressure manometer deflects to -8 cmH₂O before rising, what is the appropriate adjustment?
Increase the sensitivity setting

98. If the IPPB unit fails to cycle into expiration after initiating a breath, what should be checked?
Check for leaks in the circuit

99. If a patient’s heart rate rises from 68 to 86 bpm during an albuterol IPPB treatment, what action is appropriate?
Continue to monitor; HR increased within acceptable range (<20 bpm change)

100. A post-IPPB ABG shows pH 7.52, PaCO₂ 29, PaO₂ 99. What should the patient be instructed to do?
Slow their breathing to reduce CO₂ loss and prevent respiratory alkalosis.

101. What should not be activated when setting up a Bird Mark 7 for IPPB therapy?
Expiratory timing device

102. What is the purpose of the terminal flow knob on the PR-2?
To compensate for small system leaks

103. If a patient is unable to trigger an IPPB breath, what steps should be taken?
Increase sensitivity, check connections, confirm gas supply, and ensure tight seal around the mouthpiece.

104. What should be documented after each IPPB treatment?
Duration, medication and dosage, peak pressure, patient response, and sputum production.

105. What is the function of the Venturi system on Bird Mark and PR-2 machines?
To provide air entrainment and control oxygen concentration

106. What action prevents premature cycling during IPPB?
Instructing the patient to relax and not exhale until the machine cycles off

107. If an IPPB machine does not cycle off during treatment, what is the most likely cause?
A leak in the system

108. When does the exhalation diaphragm deflate on Bird Mark or PR-2 devices?
During exhalation

109. How can a therapist monitor patient effort and pressure during IPPB therapy?
By observing the manometer on the device

110. What are potential causes of premature cycling on the Bird Mark 7?
Kinked tubing, excessive flowrate, or patient exhaling into the machine

111. What interface can be used for edentulous patients during IPPB therapy?
A flanged mouth shield

112. What IPPB setting reduces the patient’s effort to initiate a breath?
Sensitivity control

113. What type of pressure does IPPB deliver to patients?
Positive pressure

114. Besides medication delivery and short-term ventilation, what is another key purpose of IPPB?
Lung expansion therapy

115. What happens when a patient initiates a breath into the IPPB circuit?
A negative pressure is created, triggering a positive flow of gas to begin.

116. If the control pressure is set to 12 cmH₂O on an IPPB machine, when does inspiration end?
When the pressure in the system reaches 12 cmH₂O.

117. To operate a Bird Mark or Bennett device for IPPB therapy, the high-pressure hose must be connected to:
A 50 psig source of gas.

118. During IPPB, why is a small flow of gas directed to the exhalation drive line during inspiration?
To inflate the exhalation diaphragm, closing the exhalation port so gas flows to the patient.

119. What occurs when gas flow stops to the exhalation port in an IPPB circuit?
The exhalation diaphragm deflates, opening the port to allow patient exhalation.

120. On the Bird Mark 7, what receives gas flow during inspiration to direct gas to the patient?
The exhalation diaphragm.

121. When does inspiratory gas flow end on the Bennett PR-2 and Bird Mark devices?
PR-2: When control pressure is reached; Bird: When pressure side reaches preset pressure.

122. What is the role of the Venturi and brass filter in the Bird Mark?
To allow room air entrainment and filter out dust and debris from ambient air.

123. What is the terminal flow control on the Bennett PR-2 used for?
To compensate for small leaks and allow the machine to cycle off, especially when using a mask.

124. If the air dilution control is pulled out and the device is connected to compressed air, what is the FiO₂ delivered?
21%

125. What is the function of the NEEP (Negative End Expiratory Pressure) control on the Bennett PR-2?
It is never used in typical IPPB therapy.

126. What is the function of the Bennett valve during IPPB therapy?
It controls gas flow during the inspiratory phase.

127. Which control increases the response of the Bennett valve to patient effort?
Sensitivity control.

128. What causes the Bennett valve to close as inspiratory flow decreases?
A counterweight inside the valve assembly.

129. Which control should be adjusted to compensate for a leak when using a mask or in patients with a nasogastric tube?
Terminal flow.

130. If a patient’s flow demand is high and the peak flow is at maximum, what other setting may need to be increased?
Control pressure.

131. When should the rate and expiratory time controls be used during IPPB therapy?
They should remain turned off; not used during treatment.

132. Which control must be turned off during IPPB bronchodilator therapy?
Negative pressure (NEEP) control.

133. If system pressure drops or fails to rise steadily after patient triggers a breath, what adjustment should be made?
Increase the flow setting.

134. Bird Mark series IPPB machines are:
Patient-triggered, pressure-cycled, and pneumatically powered.

135. On the Bird Mark, where does negative pressure occur as the patient initiates inspiration?
On the pressure side of the machine.

136. What does a pressure drop on the pressure side cause during IPPB therapy?
It pulls the magnet away from the clutch plate.

137. What determines how much patient effort is needed to pull the magnet from the clutch plate?
The sensitivity setting.

138. What happens if the nebulizer cup is loose or cross-threaded during therapy?
A leak is created, preventing the machine from cycling off.

139. What can occur if the patient forcefully inhales into the IPPB circuit?
The inspiratory phase may end prematurely.

140. If the patient has difficulty triggering a breath, what actions can help?
Clean the Bennett valve and adjust the sensitivity.

141. A loose nebulizer cup, disconnected tubing, or a damaged diaphragm during IPPB all indicate what?
A leak in the circuit.

142. What is the function of the ceramic switch in the Bird Mark?
It controls whether gas is directed to the patient (pressure side) or stops flow (ambient side).

143. What could cause the Bird Mark to cycle off prematurely?
A kinked or obstructed main tubing.

144. If the system pressure needle drops before reaching the peak and cycling off, what adjustment is needed?
Increase the peak flow setting.

145. What should you do if a patient experiences dizziness or lightheadedness during an IPPB treatment?
Stop the treatment temporarily and reassess the patient’s ventilation status and vital signs.

146. What is the effect of increasing the inspiratory pressure setting on an IPPB machine?
It increases the delivered tidal volume to the patient.

147. What action should be taken if a patient coughs excessively during an IPPB session?
Pause the treatment, allow the patient to recover, and ensure proper positioning and humidification.

148. Why should nose clips be used during IPPB therapy with a mouthpiece?
To ensure all the inspired gas is inhaled through the mouth, improving effectiveness of the therapy.

149. What is a potential hazard of using excessive flow during an IPPB treatment?
It may cause patient discomfort, turbulent airflow, or early cycling of the machine.

150. When is it appropriate to discontinue IPPB therapy?
When clinical signs improve, therapy goals are met, and the patient can maintain adequate ventilation without assistance.

Final Thoughts

Intermittent positive pressure breathing (IPPB) is a valuable tool in respiratory therapy used to expand the lungs, improve ventilation, and prevent complications such as atelectasis. Though it is capable of providing ventilatory support, its primary use is as a short-term, supportive therapy—not a substitute for mechanical ventilation.

IPPB is especially helpful for patients who cannot engage in voluntary breathing exercises, offering benefits like improved oxygenation, enhanced cough effort, and better secretion clearance.

For alert and able patients, incentive spirometry remains the first-line approach due to its simplicity, safety, and effectiveness. However, IPPB serves as an essential alternative when deeper, assisted breaths are required to achieve therapeutic goals.