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Continuous Positive Airway Pressure Devices. ALS / BLs Continuing Education Amy Gutman MD ~ EMS medical Director. Overview. Review CPAP goals & physiology Indications & contraindications EBM literature review OEMS protocol & medical director review.
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Continuous Positive Airway Pressure Devices ALS / BLs Continuing Education Amy GutmanMD ~ EMS medical Director
Overview • Review CPAP goals & physiology • Indications & contraindications • EBM literature review • OEMS protocol & medical director review
What is CPAP (Continuous Positive Airway Pressure)? • High-flow, pressurized & concentrated O2 delivery system • Exhalation port flow restriction device provides positive end expiratory pressure (PEEP) at a set level throughout inspiration & expiration preventing upper airway structures from collapsing &“splinting” open alveoli • By placing airway under a constant level of pressure throughout the respiratory cycle, obstructions are "pushed" out of the alveoli • Increased intrathoracic pressure reduces preload & afterload, improving left ventricular function • Maintains patency of small airways & alveoli • Improves gas exchange & reduces work of breathing by moving fluid into vasculature • Improves bronchodilator delivery • Noninvasive option to support pts through a respiratory crisis, avoid ETI, or buy time until ETI can be performed in a more controlled environment
CPAPvsBiPAP • CPAP • “Continuous” constant positive pressure throughout respiratory cycle • BiPAP • “Bilevels” (2) of positive pressure during different phases of the respiratory cycle • When pt breathing in, Inspiratory Positive Airway Pressure (IPAP) exerted • When pt breathing out, Expiratory Positive Airway Pressure (EPAP) exerted • “Effects of BiPAP in patients with COPD” (European Respiratory Journal; 2000 ) • BiPAP causes higher intrathoracic pressures & reduces myocardial perfusion • BiPAP causes lower tidal volumes & increases work of breathing (vs CPAP)
CPAP O2 Delivery • Prehospital CPAP devices powered by an O2 source that can deliver 50 psi • Some generators have a fixed flow rate, while others can be adjusted • Fixed rates are either 35% or 100% but actual O2 concentration will be less depending on leaks and minute ventilation • Variable rate increases chance of inadequate oxygen supply • The percentage of oxygen delivered (FiO2) usually starts at 30% & can be increased depending on pt needs • At 28-30% FiO2 , a full tank should last approximately: • D cylinder = 28 minutes • E cylinder = 40-50 minutes • M cylinder = 4 hours
Branson R, Davis K, Johannigman J. Comparison of continuous flow & a demand CPAP system for use in emergency care of CHF. PrehospEmerg Care. 2001 Apr-Jun;5(2):190-6. • The low flow Whisperflow device had a lower gas consumption than the fixed Whisperflow. E-cylinder operation duration was highest with the Whisperflow fixed compared to other devices • Whisperflow Low Flow • FIO2 30% • Gas Consumption 10 L/ min • Gas Consumption with 5L/min Leak 10 L/ min • Duration of Operation 60 mins • Whisperflow Fixed • FIO2 30% • Gas Consumption 15 L / min • Gas Consumption with 5L/min Leak 15 L/ min • Duration of Operation 30 mins
Indications • Increased work of breathing & inability to effectively remove CO2 • Poor respiratory effort & decreased air movement results in CO2 levels rising, causing a narcotic like effect on the brain (“CO2 Narcosis”) • Combined effects of fatigue & rising blood levels of CO2 lead to further lowering of the ventilation rate & respiratory failure
Contraindications • Need for emergent ETI • Hypotension • Cannot follow commands • Aspiration risk • Upper GI bleed / persistent vomiting • Recent facial trauma / surgery • Tracheostomy • Chest trauma / suspected pneumothorax • Claustrophobic (make an attempt)
Side Effects • Anxiety (most common) • As CPAP increases intra-thoracic pressure & gastric distention, there is a risk of hypotension & PTX • Abruptly stopping treatment can result in acute decompensation & need for ETI • Give hospital advance notice, so they can prepare
COPD • Lungs lose elastic recoil from scarred alveoli & bronchioles scar • Hypercarbic (ventilation issue) • Traditional therapies involve brochodilators (requires adequate ventilation) • Difficult to ETI prehospitally without RSI • Bronchioles collapse during exhalation leading to alveolar air trapping • “Pursed lip” breathing increases “auto-PEEP” • COPD patients requiring ETI have worse outcomes than if managed conservatively • Higher mortality & difficult to wean off ventilator rate if ETI
Aultman Study: COPD • 55 pts in CPAP group • 3 intubations • 43 pts in no CPAP group • 15 intubations • 30% reduction in ETI
Congestive Heart Failure • Incidence • 1:100 pt transports > age 65 yo • 25% medicare admissions • Average LOS 6.7 days (longer if ETI) = 6.5 million hospital days annually • Increased interstitial fluid interferes with gas exchange / oxygenation • Lymphatics remove 10-20cc pulmonary fluid/ hr • When capability exceeded, fluid accumulates in alveolar air spaces, “drowning” pt • Increased myocardial workload resulting in higher O2 demands in pts who often have concominant ischemic heart disease • Traditional therapies designed to reduce pre-load & after-load as well as remove interstitial fluid • CPAP “pushes” fluid out of alveoli back into the vascular & lymphatic tissues • 33% have ETI if no attempts at non-invasive pressure support • Intubated pts have 4 X greater mortality of non-intubated pt
Aultman Study: CHF Patients • 51 pts in CPAP group • 1 Intubation • 82 pts in no CPAP group • 22 Intubations • 25% reduction in ETI
Asthma • Bronchospasm & increased work of breathing • Pts cannot physically move air in & out of the lungs due to spasm • CPAP delivers aerosolized medications & “splints” open spasming alveoli & bronchioles
Aultman Study: Asthma • 19 pts in CPAP group • 3 intubations • 7 pts in no CPAP group • 2 intubations • 12% reduction in ETI
Equipment • Easy to use & portable • Adjustable to patient’s needs • Easily started & discontinued • Provide quantifiable & reliable airway pressures • Conservative oxygen utilization • Limited interference with administration of “traditional” cardio-respiratory therapies
Necessary Components • Oxygen source capable of producing 50 psi • Tight fitting mask • Flow regulator • 30% fixed O2 concentration • When attached to an O2 cylinder, the primary regulator delivers 50 psi & device "sucks" in room air to dilute the 100% O2
PEEP Valve • PEEP valve connected to exhalation port to maintain a constant circuit pressure • Each PEEP valve rated at a certain level measured in 2.5 cmH2O increments • Common increments are 5.0 or 7.5 cmH20
Important Points • Continually check for air leaks & pt tolerance • Do not break seal to administer medications • Even if status improves, continue CPAP until transferred to ED & personnel transfer pt to their equipment • If status deteriorates, discontinue CPAP & prepare for ETI • Notify destination hospital that CPAP is been used
CPAP vs. Intubation CPAP ETI • Non-invasive • Easily discontinued • Easily adjusted • BLS skill* • Minimal complications • Does not require sedation • Minimal infection risk • Comfortable and physiologic • Invasive • Requires mechanical ventilation • ALS skill • Significant complications • Requires sedation or RSI • Potential for infection • Uncomfortable and non-physiologic *Not according to MA OEMS, unfortunately
Prehospital CPAP Research • Provides greatest benefit when initiated early • Decreases intubations & improvement in respiratory symptoms with no major complications • In Helsinki CPAP used for >12 yrs on mobile ICUs for respiratory distress • Improved oxygenation, lowered respiratory rate, HR & SBP • Patients who were initially misdiagnosed as having CHF (i.e. pneumonia or effusion) had no adverse side effects from CPAP
Prehospital Use of CPAP for Acute Severe CHF(JEMS. 2011) • OBJECTIVE: • To describe the prehospital use of CPAP for patients presenting with acute severe HF in urban NJ • METHODS: • Retrospective review of pts treated for acute CHF • Inclusion criteria: were: RR >25 bpm, respiratory distress, history of CHF, intact mental status • Data collected: demographics, vitals, need for ETI, complications • RESULTS (STATISTICALLY SIGNIFICANT): • 387 pts met inclusion criteria, 149 had CPAP placement (39%) • Prehospital treatment times :CPAP 30 min; non-CPAP 31 min • Increase in O2 sat: CPAP 9%; non-CPAP 5% • SBP reduction: CPAP 27 mmHg; non-CPAP 19.9 mmHg • HR reduction: CPAP 17 bpm; non-CPAP 9 bpm • RR reduction: CPAP 6 bpm; non-CPAP 4 bpm • ETI reduction: CPAP 2%; non-CPAP 6% • CONCLUSION: • CPAP for eligible patients with acute severe CHF feasible & beneficial
Evaluation of the effect of prehospital application of CPAP therapy in acute respiratory distress. (Prehospital Disaster Med. 2010) • OBJECTIVE: • Test impact of CPAP on rural prehospital pts with acute respiratory distress • METHODS: • 8 month, crossover, observational, non-blinded study • RESULTS: • During the 4 months of baseline data collection, 8% pts with respiratory distress were ETI within 1st 48 hours of care with an average ICU LOS of 8 days • During the four months when CPAP available in the prehospital setting, ETI not required for any patients in the field or in the ED, with 2 ICU admissions (average LOS 4 days) • CONCLUSIONS: • The use of the CPAP in the prehospital setting is beneficial in acute respiratory distress
Current Prehospital CPAP Research • “Noninvasive Ventilation in Acute Cardiogenic Edema” JAMA, 2005 • Meta-analysis of 22 studies with “good to excellent data” showed a 45% reduction in mortality and a 60% reduction in ETI • Warner. “Evaluation of the effect of prehospital application of CPAP therapy in acute respiratory distress”. Prehosp Disaster Med. 2010 • The use of prehospital CPAP is beneficial for pts in acute respiratory distress • Sullivan. “Prehospital use of CPAP: Positive pressure = positive patient outcomes”. Emerg Med Serv, 2005 • CPAP alleviates symptoms & decreases need for ETI for pts with CHF, COPD & asthma. CPAP does not replace ETI, rather is a less-invasive means of providing respiratory support while medications work to correct underlying causes of distress • Bledsoe. Low-fractional oxygen concentration continuous positive airway pressure is effective in the prehospital setting. PEC, 2012 • CPAP using a low FiO2 (28%-30%) was highly effective in the treatment of commonly encountered prehospital respiratory emergencies
Hubble. “Estimates of cost-effectiveness of prehospital CPAP in the management of acute pulmonary edema” PEC. 2008 • METHODS • A cost-effectiveness model of implementing CPAP in an urban EMS system was derived from the societal and implementing EMS systems’ perspectives • RESULTS • Cost of consumables, equipment & training = $89 per CPAP pt • An EMS system would be expected to use CPAP 4:1000 EMS pts & expected to save 0.75 lives:1000 EMS pts at a cost of $490 per life saved • CPAP results in one less intubation per 6 CPAP applications to reduce hospitalization costs by $4075 per year per CPAP application • CONCLUSION • Aside from the ultiple studies have demonstrated the effectiveness of CPAP in the management of acute pulmonary edema, prehospital CPAP also appears to be a cost-effective treatment for these patients
Aultman Study: Summary CPAP Group (n = 148) Control Group (n = 161) Key Point: 91% of all comers in the CPAP Group did not require prehospital ETI; 65% in the Control Group did require ETI to equal a 26% reduction in prehospital ETI
Wisconsin EMT–Basic Study • Can EMT-Bs apply CPAP as safely as EMT-Ps? • 50 EMT-Basic services • 2 hour didactic, 2 hour lab, written & practical test • Because EMT–Basics don’t diagnose a unique “Respiratory Distress” protocol used to capture patients • Required data collection • Criteria used to apply CPAP • Absence of contraindications • Q 5 min. vitals • Subjective dyspnea score
Wisconsin EMT–Basic Study Results • 500 applications of CPAP in 114 services • 99% met criteria for appropriate CPAP application • No field intubations required by ALS intercepts and no significant complications • All O2sats improved, dyspnea scores reduced by 50% • Results replicated in 20+ studies since, demonstrating that pts receiving prehospital CPAP have a significantly lower incidence of ETI compared to conventional “respiratory distress” therapy • Pts not receiving prehospital CPAP 6 x more likely to require ETI(Marchetta et al) • CPAP group 355 days less LOS • If CPAP + intubation patients still had 6 days fewer LOS • ICU Admission reduced 62%
Points to Consider • How good is your current therapy for respiratory distress? • Aggressive nitrates for CHF? • Aggressive use of bronchodilators? • Prehospital & ED intubation rate? • Do you have active medical oversight? • Advanced airway management is considered a sentinel event • ALS or BLS or BOTH?
OEMS 3.4 Bronchospasm / Respiratory Distress Assessment & Treatment Priorities • Scene safety, BSI • Maintain open airway, assist ventilations prn, administer oxygen as needed • Check hemodynamic stability, symptoms, LOC, ABCs, vitals, monitor / ECG • Obtain OPQRST & SAMPLE • Determine level of respiratory distress • Mild: Slight wheezing. mild cough, able to move air without difficulty • Severe: Poor air movement, dyspnea, use of accessory muscles, tachypnea, tachycardia. May present without wheezes • Rapid transport w/ wo ALS. Do not allow pt to exert themselves in a position of comfort or appropriate to treatment(s) required
OEMS 3.4 Bronchospasm / Respiratory Distress BLS Procedures • Activate ALS intercept but initiate rapid transport w / wo ALS • Mild Distress: • Encourage &/or assist pt to self-administer their prescribed inhaler if indicated • Continually reassess vitals • Contact Medical Control to: • Repeat a 2nd MDI dose if required & if maximum dose not reached • Assist in using MDI • Use MDI if not specifically been prescribed for patient
OEMS 3.4 Bronchospasm / Respiratory Distress ALS Procedures • Mild Distress: • Albuterol 2.5-3 mg neb, with additional treatments prn • Severe Distress: • Advanced airway management prn with capnography • Albuterol 2.5-3 mg neb or MDI +/- Ipratropium 500 mcg • Additional neb treatments administered prn w / wo magnesium 2 gms IV • IV NS KVO; if SBP <100 mmHg administer 250 cc bolus or titrate to HD status • Administer CPAP if not contraindicated; nebulizer therapy can be continued with CPAP • Contact Medical Control to/for: • Repeated albuterol or ipratropium neb or MDI • Epinephrine 0.15-0.3 mg IM (may q15 min.) or 1:10,000 (NOT 1:1000), 0.1 mg- 0. 5 mg slow IVP • Magnesium Sulfate 2-4 gms IV over 5 mins • CAUTION • Use of epinephrine in pts >40 yo or with known cardiac disease or in pts who have already taken high dosage of inhalant bronchodilator medications may result in cardiac complications
OEMS 3.5 CHF / Pulmonary Edema Treatment / Assessment Priorities • Scene safety & BSI • Maintain open airway, assist ventilations & administer O2 prn • Place pt in position of comfort • Determine hemodynamic stability, symptoms, LOC, ABCs, vitals, +/- monitor & ECG • OPQRST & SAMPLE history • Rapid transport w / wo ALS, do not allow pt to exert themselves & place in position of comfort
OEMS 3.5 CHF / Pulmonary Edema BLS Procedures • Activate ALS intercept if necessary & available • Rapid transport, w / wo ALS • Notify receiving hospital
OEMS 3.5 CHF / Pulmonary Edema ALS Procedures • Advanced airway management w/ capnography if indicated • IV NS KVO en route to the hospital • If SBP < 100 mmHg administer 250 cc bolus or titrate to HD status • NTG SL or spray if SBP > 100 mmHg; may repeat q5 mins x 2 • If pt has taken a PDE5- inhibitor (i.e. Viagra) do not administered without a medical control order • Contact Medical Control if SBP <100 mmHg • Contact Medical Control for / if: • Nitropaste 1 inch to anterior chest wall • Furosemide 20-40 mg IVP or 40-80mg IVP if patient already on diuretics • Dopamine 2 - 20 mcg/kg/min • To facilitate ETI Medical Control may order Midazolam 2.5 mg IN or slow IVP. Repeat prn to a total dose of 5 mg
Summary • CPAP alleviates respiratory symptoms & decreases need for intubation for patients with respiratory distress • Safe, portable & easy to apply • Does not replace ETI, but is a less-invasive means of providing respiratory support while medications work to correct the underlying cause of respiratory distress • Better results with rapid & aggressive utilization for the majority of patients with respiratory distress • The earlier CPAP placed, the better the outcomes • Use your medical control!
References • Keith Wesley MD. Wisconsin State EMS Medical Director • Mark Marchetta RN, BS, NREMT-P; Mark Resanovich, EMT-P. Aultman Health Foundation (Canton, Ohio) • OEMS website and MA State Prehospital Treatment Protocol • Brady & Mosby Textbooks “Respiratory Distress” • Also see references cited throughout presentation