Acute Respiratory Distress Syndrome [ARDS] & Massive Hemoptysis

Massive Hemoptysis Positioning: Immediately roll the patient into the lateral decubitus position with the bleeding lung DOWN [1]. Set up dual DuCanto large-bore suction catheters (internal diameter 6.6 mm) connected to two separate wall-suction regulators at −300 mmHg.
ARDS Positioning: Elevate head of bed to 30°–45° and apply HFNC (60 L/min, FiO₂ 1.0) or Helmet CPAP/NIV (10–12 cmH₂O) for preoxygenation [2,3].

Hemoptysis: Exploits gravity to prevent blood from spilling across the carina into the non-bleeding dependent alveolar beds (preventing asphyxiation before exsanguination; normal anatomical dead space is only ∼150 mL) [1].
ARDS: Recruits dorsal atelectatic alveoli and expands functional residual capacity (FRC) prior to apneic induction [2].

Hemostatic Resuscitation (Hemoptysis):
1. Nebulized Tranexamic Acid (TXA): 500 mg (5 mL of 100 mg/mL IV solution) undiluted via standard jet nebulizer over 15 min [4].
2. IV TXA: 1 g IV in 100 mL NS over 10 min.
3. Reverse coagulopathy (4-Factor PCC 25–50 units/kg for Warfarin/DOACs; Desmopressin 0.3 mcg/kg IV for uremic/antiplatelet dysfunction) [1].

Lysine-analog competitive inhibition of plasminogen activation at the bleeding mucosal surface; prevents fibrin clot degradation within ruptured high-pressure bronchial arteries [4].

Hemodynamically Neutral RSI & Airway Isolation:
• Induction: Ketamine 1–1.5 mg/kg IV (or Etomidate 0.3 mg/kg IV) + Rocuronium 1.2–1.5 mg/kg IV.
• Hemoptysis Tube: Insert the largest possible single-lumen endotracheal tube (≥ 8.5 mm ID). If unilateral torrential hemorrhage prevents visualization, perform selective mainstem intubation of the non-bleeding lung (rotate ETT 90° counterclockwise for left mainstem; advance to 28–30 cm at teeth) or place an Arndt/Cohen Endobronchial Blocker into the bleeding bronchus [1].

High-dose Rocuronium abolishes the cough reflex within 45 sec (coughing generates > 150 cmH₂O intrathoracic pressure spikes that shear bronchial arterial clots). An ≥ 8.5 mm ETT accommodates a therapeutic flexible bronchoscope (6.0 mm OD) without occluding ventilation, whereas a Double-Lumen Tube (DLT) has narrow lumens that rapidly clot off [1].

Lung-Protective Mechanical Ventilation (ARMA Protocol):
• Calculate Predicted Body Weight (PBW):
Male PBW (kg) = 50 + 0.91 × (Height in cm − 152.4)
Female PBW (kg) = 45.5 + 0.91 × (Height in cm − 152.4)
• Set Tidal Volume (Vₜ): 6 mL/kg PBW (reduce to 4 mL/kg if needed) [5].
• Measure Plateau Pressure (Pₚₗₐₜ) via 0.5 sec inspiratory hold: Keep Pₚₗₐₜ ≤ 30 cmH₂O [2,5].
• Check Driving Pressure (ΔP = Pₚₗₐₜ − PEEP): Target ΔP < 15 cmH₂O [6].

In ARDS (“Baby Lung” concept), only 20–30% of alveoli remain aerated. Standard 10 mL/kg volumes overdistend healthy alveoli (volutrauma) and trigger cyclic alveolar opening/collapse (atelectrauma), driving systemic cytokine spillover (biotrauma) and multiorgan failure [5,6].

Refractory Hypoxemia & Definitive Source Control:
• ARDS (PaO₂/FiO₂ < 150 mmHg): Initiate Prone Positioning for ≥ 16 hours/day [7] and consider Cisatracurium bolus 15 mg (0.15–0.2 mg/kg) IV followed by 37.5 mg/hr infusion for severe patient-ventilator dyssynchrony [2,8].
• Massive Hemoptysis: Emergent CT Bronchial Angiography (CTBA) if stabilized, followed immediately by Interventional Radiology Bronchial Artery Embolization (BAE) [1].

Prone Positioning: Eliminates compressive cardiac and mediastinal weight on dorsal lungs, homogenizes pleural pressure gradients, and matches dorsal perfusion with newly recruited dorsal alveoli [7].
BAE: Directly cannulates and embolizes the systemic high-pressure bronchial arteries (120/80 mmHg) responsible for 90% of massive hemoptysis [1].