Effect of Prehospital Continous Positive Airway Pressure (CPAP)

On Physiologic Measures Including Capnography David E. Slattery, MD 1,2,5; Ryan Hodnick, DO 1,2; Bryan Bledsoe, DO 1,2,3; Eric Anderson, MD 4; Larry Johnson, NREMT-P 1,3,4 ;

Eric Dievendorf, NREMT-P 1,4; Stephen Johnson, NREMT-P 1,3

1 University of Nevada School of Medicine; 2 University Medical Center of Southern Nevada, 3 MedicWest Ambulance; 4American Medical Response, Las Vegas, Nevada; 5Las Vegas Fire and Rescue

BACKGROUND

Continuous positive airway pressure (CPAP) devices

for noninvasive ventilation (NIV) have become

increasingly more common in the prehospital

setting.1-2 It has been demonstrated to be effective

in the management of acute pulmonary edema as

well as other respiratory conditions.3-5 CPAP has

been shown to be cost-effective and reduces the

need for intubation.6-8

OBJECTIVE

To determine the effects of prehospital CPAP on

objective physiologic measures, including

capnography (ETCO2), in shortness of breath

patients.

METHODS

Prospective, observational, non-blinded study of

patients age >18 evaluated by EMS for acute

dyspnea. Inclusion Criteria: Patients meeting 2

or more of the following criteria were enrolled:

retractions or accessory muscle use, respiratory

rate (RR) greater than 25 breaths/minute, or

SpO2 less than or equal to 94% (see Figure 1).

Patients were excluded for: inability to follow

commands, apnea, vomiting/GI bleed, and major

trauma. Paramedics applied the CPAP (Pulmodyne

O2-ResQ™) (see Figure 2) and used a standardized

data collection tool to record initial and repeat

physiologic parameters at 5-minute intervals.

The following data were captured: blood pressure ,

heart rate, RR, SpO2, and ETCO2. The primary

outcome measure was the proportion of patients

with an initial RR >25 who improved (defined as a

decrease in the final RR by >5) after CPAP.

Secondary outcome measures: Proportion with

improved SPO2-defined as those with initial

SPO2 <90% improved to >95%; proportion with

improved ETCO2 (>40 to <40); the proportion who

required intubation by EMS or immediately

upon ED arrival; and subjective assessment of

efficacy by treating EMS personnel.

RESULTS

•109 patients were enrolled.

•42 % (46/109) were female.

•Average age = 67.1 (range 21-96 years)

Conditions treated based on paramedic

impression included:

•Asthma 22%,

•COPD 42%,

•CHF 49%, and

•Pneumonia 23%.

Primary outcome measure:

•Of those with an initial RR >25, 45/97

(46.4% 95%CI=37-56) improved.

Secondary measures:

•Of those with an initial SPO2 <90,

improvement was achieved in 26/76 (34.2%

95%CI=25-45); for those with ETCO2>40,

7/18 (38.9 % 95%CI=20-61) improved;

12/109 (11% 95%CI= 6-18 )

required EMS intubation. (see Figure 3)

Limitations

Small study size, incomplete ETCO2 data,

hospital intubation rates and length of stay

not measured, non blinded, no comparison

group.

CONCLUSIONS

In our cohort, prehospital CPAP application

for acute dyspnea resulted in a similar level

of improvement in oxygenation and

ventilation parameters.

REFERENCES 1. National Association of EMS Physicians. Noninvasive positive pressure

ventilation. Prehosp Emerg Care. 201115:418.9

2. Daily JC, Wang HE. Noninvasive positive pressure ventilation: resource

document for the National Association of EMS Physicians position statement.

Prehosp Emerg Care. 2011;15:532-538.

3. Hubble MW, Richards ME, Jarvis R, Millikan T, Young D. Effectiveness of

continuous positive airway pressure in the management of acute pulmonary

edema. Prehosp Emerg Care. 2006;10:430‐439.

4. Kallio T, Kuisma M, Alaspää A, Rosenberg PH. The use of prehospital

continuous positive airway pressure treatment in presumed acute severe

pulmonary edema. Prehosp Emerg Care. 2003;7:209‐213.

5. Gray A, Goodacre S, Newby DE, et al. Noninvasive ventilation in acute

cardiogenic pulmonary edema. N Engl J Med. 2008;359:142‐151.

6. Hubble MW, Richards ME, Wilfong DA. Estimates of cost--effectiveness of

prehospital continuous positive airway pressure in the management of acute

pulmonary edema. Prehosp Emerg Care. 2008;12:277‐285.

7. Simpson PM, Bendall JC. Prehospital non-invasive ventilation for acute

cardiogenic pulmonary oedema: an evidence-based review. Emerg Med J.

2011;28:609‐612.

8. Wang HE, Balasubramani GK, Cook LJ, Yealey DM, Lave JR. Medical

conditions associated with out‐of‐hospital intubation. Prehosp Emerg Care.

2011;15:338-346..

Clear a shock

Figure 3. Initial RR >25, 45/97 (46.4% 95%CI=37-56) improved >5,

initial SPO2 <90, improvement (>95%) achieved in 26/76 (34.2%

95%CI=25-45); for those with ETCO2 >40,7/18 (38.9 % 95%CI=20-61)

improved to ETCO2 < 40; 12/109 (11% 95%CI= 6-18 ) required EMS

intubation.

Figure 1. Protocol used by both Agencies

Per

centa

ge

Figure 2: Pulmodyne O2-ResQ™

CPAP Device

NAEMSP Disclosure Statement: Authors have no conflicts of interest to disclose.

Funding: .

• No input or interpretation of data results

• No investigators received financial compensation