a. Will not suppress respiratory drive in acute asthma

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1 Status Asthmaticus & COPD with Respiratory Failure - Key Points M.J. Betzner MD FRCPc - NYEMU Toronto 2018 Overview This talk is about the sickest of the sick patients presenting with severe or near death reactive airways disease. Asthma: 1) Severe Asthma Definition as per CAEP: a. Laboured respirations b. Agitated, diaphoretic c. Difficulty speaking d. Tachycardic e. No prehospital relief with ß agonist f. FEV1,PEFR - unable or <40% predicted or best (FEV1 <1.6L PEFR <200L/ min O2 saturation <90%) 2) Near Death Asthma Definition as per CAEP: a. Exhausted, confused, b. Diaphoretic, cyanotic, c. Silent chest + poor respiratory effort d. Falling heart rate e. O2 saturation <90% (despite supplemental O2) Treatment Goals: 1) Correct hypoxia: a. Will not suppress respiratory drive in acute asthma b. Start high: FiO % c. Achieve SaO2 of 92-95% M.J. Betzner MD FRCPc

2 2) Reverse airflow obstruction: a. Epi: b. Dosing: i. 0.5 mg 1:1000 IM ii. 0.5 cc 1:10000 IV q2-3 minutes to effect c. Continuous nebs: i. Salbutamol 5 mg ii. Ipratropium 0.5 mg X 3, then q4hr d. MgSO4 2-4 g IV over 15 minutes e. If no air movement, consider: i. IV Salbutamol 4 mcg/kg IVP q 15 min 3) Treat underlying inflammatory response: Alternative Drugs: a. Steroid if not already given 1) Heliox: a. Mixture of helium & oxygen b. Low-density gas mixture which may reduce turbulent airflow c. Must be at least 60% helium problematic in hypoxic patients d. Evidence is limited e. Consider in a limited group of non-hypoxic severe asthmatics 2) Methylxanthines (Aminophylline): a. Load: 3-6 mg/kg I.V. over 30 min (1/2 if already taking), then IV infusion mg/kg/hour (follow levels). b. Not recommended in the first 4 hours of treatment as all other less toxic options should be exhausted 1st. Occasionally still used in the ICU if other measures ineffective. c. No good current evidence for use in the ED. M.J. Betzner MD FRCPc

3 If all the Above Fails - Intubation & Ventilation PEARLS: 1) Intubation technique: a. Keep patient sitting b. Ketamine 1-2 mg/kg IV c. Succinylcholine 1.5 mg/kg or Rocuronium 1 mg/kg 2) Forced Exhalation via hands on the chest 3) Slow BVM ventilation &/or very conservative initial ventilator settings: a. Cautious CO2 reduction with permissive hypercapnea until lung function improves: b. Slow RR (6-8 breaths/min) to reduce barotrauma & volutrauma c. Low tidal volumes (6-8 ml/kg) d. Low I:E ratios e. NaHCO3 as needed to keep ph>7.2 f. Frequent suctioning of mucous secretions +/- lidocaine down tube to reduce airway reactivity g. May need to switch to a pressure control mode if peak airway pressures or plateau pressures are consistently higher than 40 or 50 4) If any deterioration - consider barotrauma! 5) Maintain paralysis 6) Move as quickly as possible to inhalational anesthesia as the ultimate bronchodilator Acute Severe COPD Exacerbations: Typical Contributing Factors: 1) Superimposed respiratory infections 2) Cardiovascular deterioration 3) Smoking & other environmental exposures 4) Medication noncompliance M.J. Betzner MD FRCPc

4 5) Meds: ß-blockers, benzodiazepines, narcotics 6) Misuse of oxygen therapy 7) Metabolic derangements Differential Diagnosis: 1) Pneumonia 2) IHD 3) CHF 4) Asthma 5) PE 6) Pneumothorax Diagnostics: 1) Pulse Oximetry: a. Easy, immediate 2) ABG or VBG: 3) CXR: a. Provides accurate information about ph, PaO2 & PaCO2 b. Consider in most if not all patients presenting with an acute exacerbation a. Almost always abnormal. Comparisons with prior exams should be made b. Helpful in the diagnosis of complications such as pneumothorax, pneumonia, pleural effusions, pulmonary neoplasia c. Treatment AECOPD: 1) Oxygen: a. Target SaO2>90% M.J. Betzner MD FRCPc

5 b. Be aware that patients known to be CO2-retainers may require controlled oxygen therapy (SaO %) 2) Drug management pretty much identical to asthma with exception of progression to inhalational agent & inclusion of antibiotic coverage (if any fever, increased sputum or change in character of sputum): a. < 4 exacerbations/year: i. Amoxicillin 500mg po tid x 7-10d ii. Doxycycline 200mg po x 1d then 100mg po od x 7-10d iii. TMP/SMX 1 DS tablet po bid x 7-10d b. 4 exacerbations per year or failure of first line agent or antibiotics last 6 weeks: i. Cefuroxime axetil 500mg bid x 7-10d ii. iii. Amoxicillin-clavulanate 875mg po bid x 7-10 d For PCN allergic patients: (a) Azithromycin 500mg x 1d then 250mg po od x 4d (b) Clarithromycin 500mg po bid x 7-10d (c) Levofloxacin 500mg po od x 5-10d (d) Moxifloxacin 400mg po od x 5-10d 3) Much more defined role for Non-Invasive Ventilation: a. Preserves pt s ability to speak, eat, & cough b. Less invasive nature: c. s need for sedation d. No airway trauma e. s risk of nosocomial pneumonia f. s FRC & helps recruit under-ventilated or collapsed alveoli g. Decreased work of breathing 4) Consider the following selection criteria for BiPAP (any 2): M.J. Betzner MD FRCPc

6 a. Moderate to severe dyspnea with use of accessory muscles & paradoxical abdominal motion b. Moderate to severe acidosis (ph ) & hypercapnia (PaCO ) c. Respiratory frequency > 25 breaths/min 5) Exclusion criteria for Non-Invasive Ventilation: a. Respiratory arrest b. Cardiovascular instability (hypotension, dysrhythmias, AMI) c. Somnolence, impaired mental status, uncooperative patient d. High risk of aspiration e. Viscous or copious secretions f. Recent facial or gastroesophageal surgery g. Craniofacial trauma with fixed nasopharyngeal abnormalities h. Extreme obesity 6) BiPAP initial settings: a. IPAP usually 4-10 cm H2O, EPAP cm H2O 7) Indications for Invasive Mechanical Ventilation in AECOPD: a. Severe dyspnea with accessory muscle use & paradoxical abdominal motion b. RR>35 c. Life-threatening hypoxemia (PaO2 < 40) d. Severe acidosis (ph < 7.25) and hypercapnea (PaCO2 > 60) e. Respiratory arrest f. Somnolence or impaired mental status g. Cardiovascular complications h. Other complications (sepsis, pneumonia, PE ) i. Failure of NPPV 8) Intubate if : M.J. Betzner MD FRCPc

7 a. Respiratory or cardiac arrest b. Hemodynamic instability c. Life threatening arrhythmia d. Inability to clear secretions e. Face mask intolerance f. Worsening of level of consciousness g. Progressive worsening of dyspnea h. Worsening of ABG values 9) Ventilator settings identical to that for Asthma, however, do not try to ventilate to a normal CO2. Remember the 10:4 rule. For every chronic rise of ~10 of C02, the patient s bicarb will rise ~4. Can be used to back-calculate the patients normal baseline CO2, which should be the goal. Questions betznerm@mac.com References worth a read: 1) Laher et al. Mechanically Ventilating the Severe Asthmatic. J Intensive Care Med Jan 1 2) Menitove et al. Combined Ventilator and Bicarbonate Strategy in the Management of Status Asthmaticus. The American Journal of Medicine. Volume 74, May M.J. Betzner MD FRCPc