Major issues - Hypoxia - Hypotension - High airway pressure - Auto PEEP # [Hypoxia](https://litfl.com/post-intubation-hypoxia/) - Immediate life threats "==DOPES==" - D - Displacement of ETT - O - Obstruction of ETT - P - Patient (Pneumothorax, Pulmonary embolism, Pulmonary oedema, Collapse, Bronchospasm) - E - Equipment - ventilator problems - S - Stacked Breaths - bronchospasm and ventilator settings ### Troubleshooting hypoxia - structured approach is needed 1. ==MASH== approach or rapid assessment - M - Movement of chest - Absent? - Unequal? - Hyperexpanded? - A - Arterial saturation (SaO2) and PaO2 - via ABG - S - Skin colour of patient (turning blue? pinking up?) - H - Haemodynamic stability 2. Disconnect the ventilator and administer high-flow 100% oxygen using a BVM (this eliminates E) - Difficult to ventilate -> check D, O and consider P (can still be S) - If little chest movement is present -> likely D and O -> but still consider P (pneumothorax, significant reduction in lung compliance) 3. Troubleshooting ETT (from inside out) - EtCO2 to ensure tracheal intubation - Suction catheter/bougie to ensure ETT is not obstructed - Check the tube placement visually - preferably by bronchoscopy, alternatively laryngoscopy - Check for cuff leak, disconnection, hole in ETT - If hypoxemia is not critical, arrange urgent mobile CXR to check tube position or lung pathology - One possible resolution to eliminate all of above if situation allows -> take the tube out and replace it. 4. Troubleshooting patient problem - Perform focused exam to urgently evaluate for the following: - Pneumothorax - Lung collapse - Pulmonary oedema - Bronchospasm - Pulmonary embolus - If the patient is easy to ventilate and hypoxemia rapidly resolves -> likely ventilator setting or something must have happened to affect the ventilation status (loss of PEEP from suction, circuit disconnection) - DOTTS approach can also be used to troubleshoot step by step (see below - high pressure alarm) ### Management - Low ventilation -> increase TV and/or RR (increasing MV) - Low FiO2 -> increase FiO2 - V/Q mismatch - find and treat cause - Diffusion impairment (emphysema, fibrosis) - pressure control - Shunt (alevolar collapse or filling) - pneumonia, ARDS, collapse, C CF) - add PEEP - Stepwise escalation for refractory hypoxia 1. Optimise sedation and add neuromuscular blockade (ACURASYS NEJM 2010; benefit attenuated in ROSE NEJM 2019, still used for early severe ARDS or vent dyssynchrony) 2. Prone positioning ≥ 16 h per day for P/F < 150 (PROSEVA NEJM 2013) 3. Recruitment manoeuvre and/or higher PEEP strategy with monitoring of driving pressure (caution: ART trial JAMA 2017 showed harm with aggressive RM) 4. Inhaled pulmonary vasodilator - iNO or nebulised epoprostenol (improves oxygenation, no mortality benefit; bridge) 5. Refer for veno-venous ECMO if PaO₂/FiO₂ < 80 despite above, or pH < 7.25 with PaCO₂ > 60 (EOLIA NEJM 2018; post-hoc Bayesian reanalysis favours benefit) # [Hypotension](https://rebelem.com/post-intubation-hypotension-the-ah-shite-mnemonic/) - ==AH SHITE== - A - Acidosis - Prior to induction and intubation, patient likely was maintaining a high minute ventilation to compensate for the metabolic acidosis. - Post intubation ventilator settings need to provide similar minute ventilation to prevent acidosis - Take note of ==pre-tubed EtCO2== and ==titrate== ventilator settings to achieve similar number post intubation - 8ml/kg TV (this is upper range of ARDSNET but temporary setting should not cause any issue - afterall, acidosis would kill the patient quicker than lung injury) - High ==RR around 30+bpm== - Get a baseline ABG/VBG immediately post intubation and then continue to monitor pH and metabolic status - Is HCO3- a management option? - This is tricky - Remember H-H equation - No use of giving HCO3- if you cannot ventilate the CO2 out (pH will remain the same - some metabolic acidosis will just be replaced with respiratory acidosis) - How about lactic acidosis? - Study shows it poses a risk of impaired oxygen delivery (increased Hb affinity for O2) - This will cause downstream effect of increased lactate concentration - A - Anaphylaxis - Rare towards ketamine and etomidate - More common with roc and succ (than with atracurium) - H - Heart: Tamponade - H - Heart: Pulmonary hypertension - These patients have crap RV - Hypervolaemia, hypoxia and hypercarbia are known to worsen this further - ==Fluid boluses are unlikely to help== -> may worsen LV impingement - Give norad and treat whatever worsened the pulmonary hypertension - S - Stacked breaths / Autopeep - Stacked breath -> increased lung volume -> increased intrathoracic pressure -> impaired RV failing -> hypotension and eventually arrest - This is worsened in patients with abnormally increased lung compliance (COPD) where the increased alveolar pressure causes significant increase in intrathoracic pressure - H - Hypovolaemia - Look for any possible cause of occult hypovolaemia that was unmasked by PPV - Consider adjusting ==PEEP setting== and bolus - I - Induction agent - Any agent can cause post intubation collapse by taking away an individual's conscious drive to survive - Decrease the dose of sedative/infusion and add pressors as needed - T - Tension pneumothorax - Use ultrasound to look for it - E - Electrolytes - Succ is well known to cause succ-associated hyperkalaemia in some conditions (major burn, crush injury, ESRF) - Profound hyperkalaemia can even occur without obvious risk factors even though rare. # [High airway pressure](https://litfl.com/high-airway-pressure-ddx/) - either MAN or the MACHINE - Immediate rescue sequence "==DOTTS==" - D - DIsconnect from ventilator - O - Oxygenate with 100% O2 via BVM - T - Tube position/function - T - Tweak ventilator - S - Sonography - Machine causes - Ventilator - inappropriate settings - ventilator malfunction - Circuit - kinking - pooling of condensed water vapour - wet filters causing increased resistance - ET tube - displacement e.g. endobronchial intubation - kinking - obstruction with foreign material - Man causes - bronchospasm (e.g. asthma) - decreased compliance - lung (e.g. collapse, consolidation, pulmonary oedema) - pleural (e.g. pneumothorax, pleural effusion) - chest wall (e.g. abdominal distension, kyphoscoliosis, obesity) - patient-ventilator dysynchrony, coughing # [Auto-PEEP (breath stacking)](https://litfl.com/intrinsic-peep/) ![[Pasted image 20260303220338.png]] - Diagnosis clues - decreased sats - decreased BP - pneumothorax excluded - ventilator information - expiratory flow curve not returning to baseline - rising PIP +/- Pplat - expiratory hold manoeuvre - if PEEPi will rise above machine PEEP after several seconds - Causes - bronchospasm e.g. asthma, COPD - narrowed/kinked ETT - inspissated secretions - exhalation valves - HME filter - inadequate expiratory time - Management - Disconnect patient from ventilator - ==Connect BVM but do not ventilate== - 100% FiO2 - Allow to exhale (up to 1-2 minutes) - Now what? - Main aim is to improve the time of exhalation to prevent auto-peep (prolong I:E) - Decrease respiratory rate (only works if patient is not overbreathing the set RR) - Increase the inspiratory flow rate (change to a square wave flow pattern) - Decrease Vt - Increase the applied PEEP on the ventilator - This will NOT remove trapped air - But will improve patient-ventilator synchrony - Reduces inspiratory threshold load - Reduces work of breathing - Prevents dynamic airway collapse (similar effect as CPAP in OSA) - ==IMPORTANT to keep applied PEEP < intrinsic PEEP (typically should be 70~80% of intrinsic PEEP)== - titrate sedation; consider paralysis # Misc. ### Low system pressure - check circuit connections - check seal with patients ### High system pressure - check neck position - check for obstruction ### Low airway pressure - cuff leak - pilot balloon rupture - check connections ### High airway pressure - check patency of ETT - suction ETT - check for kinking or jaw clamping - check for cuff prolapse - spontaneous respiratory - epigastric distension - bilateral BS's - wheeze (?asthma, anaphylaxis, LVF, aspiration, PTx)