ap Slides 3q136x

Optional (AEMT), Optional (Paramedic)

Special Thanks  The Men and Women of Ada County

Paramedics for their input, advice, and good sportsmanship in developing this presentation  www.adaparamedics.com  State of Maine EMS  State of Wisconsin EMS

AP - Background  Continuous Positive Airway Pressure (AP)

and related technologies have been in use for since the 1940’ in respiratory failure.  It has been largely indicated to assist patients with primary and secondary sleep apnea, and globally this continues to be its largest market.  In recent history (1980’s) it has found wide acceptance in hospital settings (usually CCU, ICU, and ERs) for patients suffering varying degrees of respiratory failure of a wide variety of origins.  Acute Pulmonary Edema (APE) most common

AP - Background  AP is a non-invasive procedure that is easily

applied in the pre-hospital setting.  AP is an established therapeutic modality, well studied to reduce both mortality and morbidity.  AP has been shown to be an preferable alternative to intubation in some patients.

History of AP 1912 - Maintenance of lung expansion during thoracic surgery

(S. Brunnel)

1937 - High altitude flying to prevent hypoxemia.

(Barach et al)

1967 - PB + IPPV to treat ARDS

(Ashbaugh et al)

1971 - Term AP introduced, used to treat HMD in neonates (Gregory et al)

1972 - AP used to treat ARF

(Civetta et al)

1973 - AP used to treat COPD

(Barach et al)

1981 - Downs generator

(Fried et al)

1982 - Modern definition of AP

(Kielty et al)

Boussignac AP?  1973- Boeing 707 crashed near Paris  125 fatalities, 3 survivors with severe respiratory

trauma

 AP was not well known at the time.  Mortality for these injuries was 100%  Dr. Georges Boussignac, decided not to intubate these patients but to treat them instead with Non Invasive Ventilation (NIV)

and an early form of AP.

 The original AP was a bag over the head with

constant air flow at greater than atmospheric pressure.

Types of AP

Boussignac

Oxypeep

Whisperflow Flow Generators

Emergent Products PortO2vent

CAREvent® ALS + AP

Vital Terminology  Tidal Volume (Vt)

 Minute Volume (Vm)  Peak Inspiratory Flow

 Functional Reserve Capacity (FRC)  Inspired Oxygen

(FiO2)  Work of Breathing (WOB)

Airway and Respiratory Anatomy and Physiology  Pathway review  Oxygenation and Ventilation  Functional Residual Capacity  Work of breathing

Airway and Respiratory Anatomy  Pathways-

Airway and Respiratory Anatomy  Pathways-

Airway and Respiratory Physiology

A: The Pressure Gradient!!!!

Airway and Respiratory Physiology The Pressure gradient! Aveolar Air has higher

content of OXYGEN than venous (deoxygenated) blood Therefore oxygen transfers from the air into the blood. This is called the Pressure Gradient  The higher the inspired

oxygen (FiO2) the better the pressure gradient!

Airway and Respiratory Physiology  Oxygen Saturation

Curve

Picture released into public domain by wikipedia

Airway and Respiratory Physiology

FRC  Functional reserve Capacity (FRC) is the volume of

air in the lungs at the end of a normal ive expiration.

 approximately 2400 ml in a 70 kg, average-sized male

 FRC decreases with lying supine, obesity, pregnancy

and anaesthesia.  Important aim of AP is to increase functional residual capacity (FRC)  By increasing he FRC, the surface area of the Aveoli is

distended (increased).  Greater surface area improves gas exchange (oxygenation and ventilation)  This improves Spo2/SaO2

Airway and Respiratory Physiology

WOB  Work of breathing (WOB) is respiratory effort to

effect oxygenation and ventilation.  Important aim of AP is to reduce work of breathing (WOB)

Airway and Respiratory Physiology

WOB  Signs of increased WOB:  Dyspnea on Exertion (DOE)  Speech Dyspnea  Tripoding  Orthopnea  Accessory Muscle Use/Restractions  Lung Sounds  

“Doorway Test” Silent Chest!!!!

Airway and Respiratory Physiology

WOB Increased WOB : Respiratory Fatigue Respiratory Distress Respiratory Failure

AP reduces WOB

Airway and Respiratory Pathology

Airway and Respiratory Pathology CHF  Precipitating Causes  Non Compliance with Meds and Diet  Acute MI  Arrhythmia (e.g. AF)  Increased Sodium Diet (Holiday Failure)  Pregnancy (PIH, Pre-eclampsia, Eclampsia)

Airway and Respiratory Pathology CHF  Severe resp distress

 Paroxysmal nocturnal

 Foamy blood tinged 

    

sputum Accessory muscle use Apprehension, agitation Speech Dyspnea Diaphoresis Bilateral crackles or Rhales Orthopnea (can’t lie down)

 

 



dyspnea (PND) Cyanosis Pedal Edema JVD Chest pain (possible co-existent AMI) abnormal vitals (increased B/P; rapid pulse; rapid & labored respirations

Cardiac Asthma?  Fluid leaks into the Interstitial Space  Airways narrow  Mimics broncoconstriction seen in asthma 

May actually exacerbate asthma if a co-existing PMHx

 Produces “Wheezing”

Infiltration of Interstitial Space mal Micro-anatomy



Micro-anatomy with fluid movement.

Airway and Respiratory Pathology CHF

 The following treatments should be done concurrently with AP,  

 

patient condition permitting*. High Flow Oxygen!!! Nitroglycerin *  0.4 mg sl every 5 minutes;  0.5-2 inches transdermal  5-200 mcg/min IV Drip Lasix *  20- 80 mg IV/IM (or double daily dose if already on Lasix) Opiates*  Reduce Anxiety  Mild Vasodilator  2.5-5 mg q5 minutes IVP

(* = defer to local protocol or medical control)

Airway and Respiratory Pathology Asthma and COPD  Obstructive vs Reactive    

airways Bronchoconstrictive issues Poor Gas Exchange Accessory Muscle Use/Muscle Tiring AP is best reserved for those patients who are refractory to normal interventions, and have a severe presentation.  At least TWO doses of

bronchedialtors should be istered before the provider initiates AP.

Airway and Respiratory Pathology Asthma and COPD  The following treatments should be done concurrently with

AP, patient condition permitting*.  High Flow Oxygen!!!  Bronchodilators*  Albuterol 2.5 mg (0.83% in 3 cc)/ Atrovent 0.5 mg (0.02% in 2.5 cc) nebulized.  Repeat as needed with Albuterol Only.  Do not dilute.  Magnesium Sulfate* (Asthma extremis only)  IV: 2 g given SLOWLY, diluted.  Do not give faster than 1 g/minute.  Epinephrine 1:1,1000  0.3-0.5 mg IM/SQ for severe refractory bronchospasm  Use Epinephrine with caution on patients over 65 or with cardiac history.  Solu-medrol  IV/IM: 125 mg (* = defer to local protocol or medical control)

Airway and Respiratory Pathology Pneumonia  Infectious process  Often confused with, or masked by, CHF  Detailed assessment required  PMhx, Med list review  Sputum type/color  Onset of s/s

 Fever  Lack of CHF/Afib Hx

 Normal CHF Tx may be ineffective or detrimental  Nitroglycerine (ineffective)

 Diuretics (detrimental)

Airway and Respiratory Pathology Pneumonia  AP may be of minimal benefit in Pneumonia*.  High Flow Oxygen!!!  Bronchodilators*

Albuterol 2.5 mg (0.83% in 3 cc)/ Atrovent 0.5 mg (0.02% in 2.5 cc) nebulized.  Repeat as needed with Albuterol Only.  Do not dilute.  (* = defer to local protocol or medical control) 

Airway and Respiratory Pathology Drowning  AP may be beneficial to the drowning/near

drowning patient  Strongly consider intubation for severe s/s refractory to AP and other treatments

Other uses of AP         

ARDS Acute Respiratory Failure Anesthesia (Pre-Op and Post-Op) Atelectasis Alternative to Mechanical Ventilation Weaning from Mechanical Ventilation Left Ventricular Failure Renal Failure Sleep Apnea

Physiology of AP

Physiology of AP  Airway pressure maintained at set level throughout inspiration and expiration  Maintains patency of small airways and alveoli  “Stents” small airways open  “Distends” aveoli

 Improves delivery of bronchodilators  By up to 80%

 Moves extracellular fluid into vasculature  Improves gas exchange  Reduces work of breathing

Physiology of AP : AP Mechanism  Increases pressure

within airway.  Airways at risk for collapse from excess fluid are stented open.  Gas exchange is maintained  Increased work of breathing is minimized

Physiology of AP : Redistribution of pulmonary edema with AP

Physiology of AP: Hypotension  AP increases intrathoracic pressure  This decreases cardiac output causing

hypotension  Therefore hypotensive patients may have are relatively contraindicated with AP...

Physiology of AP : istration of Medications by AP  AP and Nebulizers can be used together to

provide better “penetration” of nebulizer medications through the respiratory tract.

Use of AP by EMS

Goals of AP use in the field  Primary Goals  Increase amount of inspired oxygen (FiO2)  Increase the SpO2 and PaO2 of the patient  Decrease the work load of breathing (WOB)  To reduce overall mortality  Secondary Goals:  Reduce the need for emergent intubations of the patient  Decrease hospital length of stay (LOS)

AP vs. Intubation  

  

 

AP Non-invasive Easily discontinued Easily adjusted Use by EMT-B (in some states) Minimal complications Does not (typically) require sedation Comfortable

     

Intubation Invasive Intubated stays intubated Requires highly trained personnel Significant complications Can require sedation or RSI Potential for infection

Key Point:  This module discusses AP in patients >8 years of age  AP has been safely used in children, infants, and neonates in the in-hospital and critical care settings  Local protocols may allow use in children and infants  Appropriate sized equipment mandatory  Risk increases

 Consult medical control and local protocols

Indications For consideration (for patients <8) in moderate to severe respiratory distress secondary to: CHF/APE Acute Respiratory Failure asthma/reactive airway disease, near drowning, COPD, acute pulmonary edema (cardiogenic and non cardiogenic),  pneumonia who present with any of the following:      

     

Pulse oximetry < 88% not improving with standard therapy ETCO2 > 50mmHg Accessory muscle use / retractions Respiratory rate > 25 Wheezes, rales, rhonchi Signs of respiratory fatigue or failure

A note on misdiagnosis  There is a significant misdiagnosis rate of CHF in

the field, most commonly confused with pneumonia  AP still demonstrated significant improvement in other (non-CHF/APE) respiratory emergencies  Risks are greater in non CHF/APE  AP Max Pressures are lower non CHF/APE

 Caution is required non CHF/APE

2003 Helsinki EMS Looked at “patients in Acute Severe Pulmonary Edema (ASPE)” Study Group:

121

Confirmed CHF:

38

(32%)

Miss- DX:

83

(68%)

Non CHF Patients that got better with AP:

34

(28%) (17.8%) (8%)

Non AP mortality AP Mortality Other Notes: •

Confirmed by MNP

•

Treated with Low-Mid FiO2, Nitrates. No Lasix

•

4 intubated in field (3%) (Kallio, T. et al. Prehospital Emergency Care. 2003. 7(2) )

Contraindications/Exclusion Criteria  Physiologic      

Unconscious, Unresponsive, or inability to protect airway. Inability to sit up Respiratory arrest or agonal respirations (Consider Intubation) Persistent nausea/vomiting Hypotension- Systolic Blood Pressure less than 90 mmHg Inability to obtain a good mask seal

 Pathologic       

Suspected Pneumothorax Shock associated with cardiac insufficiency Penetrating chest trauma Facial anomalies /trauma/burns Closed Head Injury Has active upper GI bleeding or history of recent gastric surgery Vomiting

Cautions  History of Pulmonary Fibrosis  Claustrophobia or unable to tolerate mask (after initial 1-2 minutes)  Coaching essential

 Consider mild sedation

 Has failed at past attempts at noninvasive ventilation  Complains of nausea or vomiting  Has excessive secretions  Has a facial deformity that prevents the use of AP

istration  AP is measured in

cm/H2O  Start with device in the lowest setting, and titrate upward.  Initial dose at 0-2 cm/H2O  Titrated up to*:

 10 cm/H2O MAX for CHF

or,  5 cm/H2O MAX for COPD, near drowning, and respiratory failure form other causes. •(* = defer to local protocol or medical control)

Selling AP?  Placing AP is an anxiety inducing event in the

hypoxic respiratory distressed patient!  Verbally calming, coaching, and preparing (AKA: Selling) your patient on AP is essential  Similar to calming a hyperventilation patient

Complications  AP may drop BP due to increased intrathoracic pressure.  A patient must have a systolic BP of at least 90mmHg to be a

candidate for AP  Increased Intrathoracic pressure means decreased ventricular filling and increased afterload, thus decreasing cardiac output and blood pressure.  Providers should be comfortable giving a AP patient NTG If they are too hypotensive for NTG, then they are too hypotensive for AP.

 Risk of pneumothorax

 Increased intrathoracic pressure = increased risk  Higher in Asthmatics and COPD

 Gastric Distention, and vomiting

 Strongly consider placement of a gastric tube (if in scope of

practice)

 Risk of corneal drying

 High volumes of air blowing at eyes, especially on long transports.

Discontinuing of AP  AP therapy needs to be continuous and should

not be removed unless the patient:  cannot tolerate the mask, success of tolerance to the treatment increased with proper coaching by EMS crew  requires suctioning or airway intervention,  experiences continued or worsening respiratory failure,  Develops severe hypotension  or a pneumothorax is suspected.  Intermittent positive pressure ventilation and/or intubation should be considered if patient is removed from AP therapy.

AP will not cure all patients! Some patients just really want a tube!

“Don’t give up too early but know when to give up”

Documentation  “Dosage”

 AP level (10cmH2O)  FiO2 (100%)

 Subjective response to

therapy  Objective response to therapy  Lung Sounds,  Work of Breathing

     

SPO2 Nasal ETCO2 SpO2 q5 minutes Vital Sign q5 minutes Any adverse reactions Justification for sedation, intubation, or discontinuation of AP. Be specific.

Documentation: Modified Borg Scale  “0”-No breathlessness at all  “1”-Very slight  “2”-Slight breathlessness  “3”-Moderate  “4”-Somewhat severe  “5”-Severe  “7”-Very severe  “9”-Very, very severe (Almost maximum)  “10”-Maximum

EMS System Implementations and Considerations  Types of AP  Oxygen source and supply  Size of tanks  Availability of “full” tanks  Availability of appropriate regulators  Duration of transport

 Destination Hospital  Turnaround time and transfer of care

AP and Intubation  Intubation will be inevitable in some patients

regardless of the use of AP, and the paramedic must be prepared for rapid intervention by RSI/MAI or other means as feasible.  Indications to proceed to ET placement are (not all inclusive):  Deterioration of mental status  Increase of the EtCO2  Decline of SpO2

 Progressive fatigue  Ineffective tidal volume  Respiratory or cardiac arrest.

POST  POST does not specifically address AP, but is

likely permissible since it is both palliative and noninvasive.

Research Review

Research Review  JAMA December 28, 2005 “Noninvasive

Ventilation in Acute Cardiogenic Edema”, Massip et. al.  Meta-analysis of studies with good to excellent

data  45% reduction in mortality  60% reduction in need to intubate

Research Review  AP therapy can improve A.P.E. patients in

Minutes.  Has been compared to D50 in hypoglycemic patients  “AP was associated a decrease in need for intubation (-26%) and a trend to a decrease in hospital mortality (-6%) compared with standard therapy alone.”

 (Pang, D. et al. 1998. Data review 1983-1997. Chest 1998;

114(4):1185-1192)

Research Review  2000 Cincinnati EMS looked at “CHF patients in

imminent need of intubation”

 19 patients included, AP istered  *Pre- and post-therapy pulse ox increased from 83.3% to

95.4%  *None of the patients were intubated in the field  *Average hospital stay reduced from 11 days to 3.5 days

“AP is to APE like D50 is to insulin shock”

-Russell K. Miller Jr, MD, FACEP

Research Review  AP in COPD:

 85 patients in a single ICU over a study period.  Randomized control group

 AP significantly reduced need of ETT in COPD patients by

48%  Complications were decreased by 32%  Mortality Decreased by 20%  “CONCLUSIONS. In selected patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation can reduce the need for endotracheal intubation, the length of the hospital stay, and the in-hospital mortality rate. “  Brochard L, Mancebo J, Wysocki M, Lofaso F, Conti G, Rauss A, Simonneau G, Benito S, Gasparetto A, Lemaire F, et al Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease. N Engl J Med 1996;334(11):743. .

Research Review BiPap vs. AP  “Though BLPAP (BiPAP) has theoretical advantages

over AP, there are questions regarding its safety in a setting of CHF. The Key to success in using NIV to treat severe CHF is proper patient selection, close patient monitoring, proper application of the technology, and objective therapeutic goals. When used appropriately, NIV can be a useful adjunct in the treatment of a subset of patients with acute CHF at risk for endotracheal intubation.”  Reviews in Cardiovascular Medicine, vol. 3 supl. 4 2002, “Role of Noninvasive Ventilation in the Management of Acutely Decompensated Heart Failure”

Research Review: BiPAP vs AP  European Respiratory Journal, vol. 15 2000

“Effects of biphasic positive airway pressure in patients with chronic obstructive lung disease”  BiPAP resulted in overall higher intrathoracic

pressures – reduces myocardial perfusion  BiPAP resulted in lower tidal volumes  BiPAP resulted in higher WOB

Research review: Prehospital AP  PEC 2000 NAEMSP Abstract, “Pre-hospital use of

      

AP for presumed pulmonary edema: a preliminary case series”, Kosowsky, et. al. 19 patients Mean duration of therapy 15.5 minutes Oxygen sat. rose from 83.3% to 95.4% None were intubated in the field 2 intubated in the ED 5 subsequently intubated in hospital “Pre-hospital AP is feasible and may avert the need for intubation”

Review  AP is not a substitute for patients needing

IPPV or intubation.  AP works best when used in conjunction with other therapies.  AP doses start at ZERO and titrate up  Max of 10 cmH2O for APE  Mac of 5 cmH2O for other causes

 AP is effective in COPD when CAREFULLY

used.

Key Points of AP  AP, while very beneficial in many patients, is not risk free.  Pneumothorax  Regurgitation and

aspiration  hypotension

Review local protocol or local Medical Director considerations

Questions?

Followed by skills check off and a written test!