Non-Invasive Ventilation for Acute Respiratory Failure

Algorithm Steps

1. ▶

   Start

   Acute Respiratory Failure

   Patient with respiratory distress requiring ventilatory support

   1. ◆

      Decision

      Type of Respiratory Failure?

      Hypoxemic vs Hypercapnic

      • Type 1 (Hypoxemic): PaO2 <60mmHg, normal/low CO2
      • Type 2 (Hypercapnic): PaO2 <60 + PaCO2 >45 + pH <7.35
      • Mixed: Features of both
      1. ◆

         Decision

         NIV Indicated?

         Check indications and contraindications

         • INDICATIONS:
         • • AECOPD with respiratory acidosis (pH 7.25-7.35)
         • • Cardiogenic pulmonary edema
         • • Immunocompromised with respiratory failure
         • • Post-extubation support
         • • Chest wall deformity/neuromuscular disease
         1. ⚠

            Warning

            ⚠️ NIV Contraindicated

            Consider immediate intubation

            • Cardiac/respiratory arrest
            • Unable to protect airway
            • Facial trauma/burns/surgery
            • Fixed upper airway obstruction
            • Vomiting/high aspiration risk
            • Undrained pneumothorax
            • Severely impaired consciousness
            1. ✓

               Outcome

               Proceed to Intubation

               NIV has failed

               • Do not delay if deteriorating
               • RSI with appropriate induction
               • Lung-protective ventilation
               • ICU admission
         2. ◆

            Decision

            Select NIV Mode

            Based on clinical indication

            • CPAP: For Type 1 failure, cardiogenic pulmonary edema
            • BiPAP: For Type 2 failure, COPD, hypoventilation
            1. ●

               Action

               CPAP Setup

               For cardiogenic pulmonary edema

               • Starting pressure: 5-10 cmH2O
               • Titrate to 10-12 cmH2O as tolerated
               • Add FiO2 to maintain SpO2 ≥94%
               • Use full face mask
               • Monitor for improvement in work of breathing
               1. ●

                  Action

                  Interface Selection

                  Choose appropriate mask

                  • Full face mask: Most common, effective
                  • Nasal mask: If claustrophobia, better tolerated
                  • Total face mask: Edentulous, facial hair
                  • Helmet: Prolonged use, less leak
                  1. ●

                     Action

                     Titrate Settings

                     Optimize ventilation

                     • Increase IPAP to improve ventilation (↓PaCO2)
                     • Increase EPAP to improve oxygenation
                     • Aim for: Tidal volume 6-8 mL/kg
                     • Target: RR <25, patient-ventilator synchrony
                     • Reduce leak to <40 L/min
                     1. ●

                        Action

                        Close Monitoring

                        Assess response to NIV

                        • ABG at 1-2 hours, then 4-6 hourly
                        • Target: pH improving toward >7.35
                        • Monitor: RR, HR, SpO2, comfort
                        • Watch for: Distension, mask leak, skin breakdown
                        1. ◆

                           Decision

                           Response at 1-2 Hours?

                           Assess clinical and ABG improvement

                           • Good: pH improving, RR decreasing, comfortable
                           • Poor: pH worsening, RR not improving, agitation
                           1. ●

                              Action

                              Continue NIV

                              Maintain as long as needed

                              • Use for as much of first 24h as possible
                              • Allow breaks for eating, nebulizers
                              • Wean over 48-72h as pH normalizes
                              • Transition to nocturnal NIV if needed
                              1. ✓

                                 Outcome

                                 Wean from NIV

                                 When clinically stable

                                 • pH >7.35 on minimal support
                                 • Reduce IPAP gradually
                                 • Increase time off NIV
                                 • Consider domiciliary NIV if recurrent
                           2. ⚠

                              Warning

                              ⚠️ NIV Failure

                              Consider intubation

                              • pH not improving or worsening after 1-2h
                              • Decreasing level of consciousness
                              • Hemodynamic instability
                              • Intolerance despite optimization
                              • Prepare for intubation
            2. ●

               Action

               BiPAP Setup

               For hypercapnic respiratory failure

               • IPAP: Start 10-12 cmH2O, titrate to 20-25
               • EPAP: Start 4-5 cmH2O
               • Backup rate: 12-16 breaths/min
               • Inspiratory time: 0.8-1.2 seconds
               • FiO2: Target SpO2 88-92%