When does a patient need Bi-Level Positive Airway Pressure (BIPAP)?

When Does a Patient Need BiPAP?

BiPAP should be initiated when a patient presents with acute respiratory distress characterized by increased work of breathing, hypercapnia with respiratory acidosis (particularly pH <7.35), or hypoxemic respiratory failure that remains inadequately oxygenated despite conventional oxygen therapy, provided the patient is alert, cooperative, and hemodynamically stable. 1, 2

Primary Indications for BiPAP

Acute Hypercapnic Respiratory Failure

• BiPAP is most effective in acute exacerbations of COPD with respiratory acidosis, showing success rates of approximately 80% (20 of 25 patients) in avoiding intubation 3
• Initiate when pH is declining and PCO2 is rising despite standard bronchodilator therapy 1
• BiPAP offsets intrinsic PEEP in COPD, recruits collapsed alveoli, and improves ventilation-perfusion matching 1

Acute Cardiogenic Pulmonary Edema

• BiPAP reduces work of breathing and improves oxygenation in acute heart failure syndrome 4
• However, be cautious as some evidence suggests BiPAP may be associated with higher myocardial infarction rates compared to CPAP in this population 4
• Consider CPAP as first-line for cardiogenic pulmonary edema unless hypercapnia is present 4

Hypoxemic Respiratory Failure

• BiPAP can be used when PaO2/FiO2 ratio is low despite high-flow oxygen 3
• Success rate is lower (approximately 48%, or 15 of 31 patients) compared to hypercapnic failure 3
• The risk of BiPAP failure is 2.6 times greater in hypoxemic versus hypercapnic respiratory failure 3

Post-Extubation Respiratory Failure

• BiPAP is highly effective (80% success rate) when initiated within 48 hours of extubation for patients developing respiratory distress 3
• Prevents reintubation and reduces ICU length of stay 3

Acute Asthma

• BiPAP may offer short-term support for patients with acute respiratory failure from severe asthma 4
• Requires that the patient is alert with adequate spontaneous respiratory effort 4
• Can delay or eliminate the need for endotracheal intubation 4

Clinical Parameters Indicating BiPAP Need

Respiratory Distress Criteria

Look for the following objective findings 2:

• Respiratory rate >30 breaths/minute
• Oxygen saturation <90% on conventional oxygen therapy
• Use of accessory muscles of respiration
• Paradoxical abdominal breathing
• Patient subjectively reporting severe dyspnea

Blood Gas Criteria

• pH <7.35 with elevated PCO2 (primary indication for hypercapnic failure) 1, 3
• PaO2/FiO2 ratio <300 despite oxygen supplementation 3
• Rising PCO2 trend despite treatment 1

Hemodynamic Stability Requirements

Patient must be 2:

• Cooperative and able to protect airway
• Hemodynamically stable (no vasopressor requirement)
• Able to tolerate face mask
• Not requiring immediate intubation

Initial BiPAP Settings

Start with IPAP of 8-10 cm H2O and EPAP of 4-5 cm H2O 2, 5

• Gradually increase IPAP by 2 cm H2O increments to 14-20 cm H2O as tolerated 1, 5
• Increase EPAP by 1 cm H2O increments to 4-8 cm H2O as needed 1, 5
• Typical effective settings: IPAP 14-20 cm H2O, EPAP 4-8 cm H2O 1, 5

Contraindications and When NOT to Use BiPAP

Absolute Contraindications

• Apnea or impending respiratory arrest (intubate immediately) 4
• Coma or severely depressed mental status 4
• Inability to protect airway 4
• Facial trauma or burns preventing mask seal 1
• Hemodynamic instability requiring vasopressors 2

Relative Contraindications

• Recent myocardial infarction (use with extreme caution in acute heart failure) 4, 1
• Severe hypoxemia unresponsive to initial trial 3
• Copious secretions or inability to clear airway 4
• Recent upper airway or gastrointestinal surgery 1

Special Populations Requiring Caution

• Patients with massive hemoptysis should have BiPAP discontinued during active bleeding 4
• Patients with pneumothorax should have BiPAP discontinued until chest tube placement 4

Monitoring Response and Success Criteria

Early Response Indicators (Within 1-2 Hours)

Successful BiPAP therapy shows 2, 3:

• Decreased respiratory rate (mean decrease from 34 to 28 breaths/minute) 2
• Improved oxygen saturation (mean increase from 80% to 91%) 2
• Reduced oxygen requirement (mean decrease from 4.6 to 2.3 L/min) 2
• Increased pH and decreased PCO2 in hypercapnic patients 3
• Increased PaO2/FiO2 ratio in hypoxemic patients 3

Duration of BiPAP Dependency

• Average duration of BiPAP use in successful cases is approximately 35 hours 3
• Perform daily trials of unassisted breathing to assess readiness for discontinuation 3

When BiPAP Fails: Intubation Criteria

Proceed to intubation if 4, 3:

• No improvement or worsening after 1-2 hours of BiPAP trial
• Persistent or worsening hypercapnia with pH <7.25
• Worsening mental status or inability to cooperate
• Hemodynamic deterioration
• Inability to manage secretions
• Patient exhaustion despite BiPAP support

Common Pitfalls to Avoid

Mask Selection and Fit

• Poor mask fit is the most common cause of BiPAP failure 1
• Ensure proper seal without excessive tightening (causes skin breakdown)
• Consider different mask types (full face vs. nasal) based on patient tolerance 1

Pressure Settings

• Excessive pressure settings can cause gastric distension or paradoxically increase work of breathing 1
• Start low and titrate gradually based on patient comfort and objective parameters 2, 5
• Do not exceed IPAP of 20 cm H2O in most adult patients 1

Patient Selection Errors

• Do not delay intubation in patients who clearly need invasive ventilation 4
• BiPAP is a temporizing measure, not a substitute for definitive airway management in unstable patients 4
• Higher APACHE II scores predict BiPAP failure—use clinical judgment 3

Monitoring Gaps

• Continuous monitoring required for first 1-2 hours 2
• Reassess blood gases within 1-2 hours to document response 3
• BiPAP failure is associated with increased mortality (18 of 28 failures died vs. 0 of 47 successes) 3