Continuous Positive Airway Pressure Devices

A L S / B L S C O N T I N U I N G E D U C A T I O N

A M Y G U T M A N M D ~ E M S M E D I C A L D I R E C T O R

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 O 2 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

CPAP vs BiPAP

 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 O 2 50 psi source that can deliver  Some generators have a fixed flow rate, while others can be adjusted   Fixed rates are either 35% or 100% but actual O 2 depending on leaks and minute ventilation concentration will be less 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 M cylinder = = 40-50 minutes 4 hours

Branson R, Davis K, Johannigman J. Comparison of continuous flow & a demand CPAP system for use in emergency care of CHF.

Prehosp Emerg 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 Gas Consumption Gas Consumption with 5L/min Leak Duration of Operation 30% 10 L/ min 10 L/ min 60 mins  Whisperflow Fixed     FIO2 Gas Consumption Gas Consumption with 5L/min Leak Duration of Operation 30% 15 L / min 15 L/ min 30 mins

Indications

 Increased work of breathing & inability to effectively remove CO 2  Poor respiratory effort & decreased air movement results in CO

(“CO 2

2 levels rising, causing a narcotic like effect on the brain

Narcosis”)

 Combined effects of fatigue & rising blood levels of CO 2 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

35% 35% 30% 25% 20% 15% 10% 5% 0% 5% CPAP CONTROL

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 O 2 concominant ischemic heart disease demands in pts who often have  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

30% 25% 20% 15% 10% 5% 0% 2% CPAP 27% CONTROL

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

30% 25% 20% 15% 10% 5% 0% 16% CPAP 28% CONTROL

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 cmH 2 O increments  Common increments are 5.0 or 7.5 cmH 2 0

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

        Non-invasive Easily discontinued Easily adjusted BLS skill* Minimal complications Does not require sedation Minimal infection risk Comfortable and physiologic

ETI

       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 O 2 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 1 st 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

Diagnosis CHF Asthma COPD Pneumonia Pulmonary Edema Other Total 2 13 3 3 0 4 1 ETI CPAP Group (n = 148) % No ETI % 50 16 52 3 11 9% 3 135 91% 22 ETI Control Group (n = 161) % No ETI % 60 2 15 2 6 5 28 6 1 9 56 35% 5 105 65% 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 O 2 sats 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. M ay 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 2 nd 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 O 2 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