Mike McEvoy, PhD, NRP, RN, CCRNSr. Staff RN – Cardiothoracic SurgeryChair – Resuscitation Committee – Albany Med CtrEMS Coordinator – Saratoga County, New YorkEMS Editor – Fire Engineering magazine

Non-Invasive Safety and Wellness Technologies

Mike McEvoy - Books:

Disclosures

• I am on the speakers bureau for Masimo Corporation.

• I am the EMS editor for Fire Engineering magazine.

• I do not intend to discuss any unlabeled or unapproved uses of drugs or products.

• Slides at: www.mikemcevoy.com

Nurses Week 2012 – Albany Medical Center (NY)

How Good Are You?

•HR

•LOC

•BP

•Resps

Not As Good As You Might Think:• 50% of physical assessments wrong

• Therapeutic interventions altered with invasive assessment 34 - 56% of the time:• 1980 Del Guercio • 1984 Eisenberg• 1990 Bailey • 1991 Steinberg • 1994 Minoz • 1998 Staudinger • 2002 Jacka, etc, etc…

How Good Are Your Monitors?

What monitors?

Pulse Oximetry

Problems:

•Accuracy

•Motion & artifact

•Dyshemoglobins

•Perfusion

Oxygenation

• Pulse Oximetry

Oxygenation

• Pulse Oximetry

Model of Light Absorption At Measurement Site Without Motion

ACAC Variable light absorption due pulsatile volume of arterial blood

DCDC Constant light absorption due to non-pulsatile arterial blood.

DCDC Constant light absorption due to venous blood.

DC Constant light absorption due to tissue, bone, ...

Abs

orpt

ion

TimeTime

Model of Light Absorption At Measurement Site With Motion

ACAC Variable light absorption due pulsatile volume of arterial blood

DCDC Constant light absorption due to non-pulsatile arterial blood.

AC Variable light absorption due to moving venous blood

DCDC Constant light absorption due to venous blood.

DC Constant light absorption due to tissue, bone ...

TimeTime

Abs

orpt

ion

Influence of Perfusion on Accuracy of Conventional Pulse Oximetry During Motion

Good Perfusion (Conventional PO)

SpaO2=98

SpvO2=88SpO2=93

Poor Perfusion (Conventional PO)

SpO2=74

SpaO2=98

SpvO2=50

Post Processor

R & IRDigitized, Filtered &

NormalizedR/IR

MEASUREMENT

CONFIDENCE % Saturation% Saturation

Conventional Pulse Oximetry Algorithm

3 options during motion or low perfusion:

1. Freeze last good value

2. Lengthen averaging cycle

3. Zero out

Next Generation Pulse Oximetry

Next Generation Pulse Oximetry

Masimo SET: Signal Extraction Technology

SET “Parallel Engines”

Masimo SET “Parallel Engines”

R/IR(Conventional Pulse

Oximetry)

Confidence Based

Arbitrator

0 50% 66% 97% 100%SpO2% SpO2%

Post ProcessorDigitized,

Filtered & Normalized

% Saturation

SSTTM

Proprietary Algorithm 4

DST DST SET – 97%SET – 97%

DSTTM

FSTTM

MEASUREMENT

CONFIDENCE

MEASUREMENT

CONFIDENCE

MEASUREMENT

CONFIDENCE

MEASUREMENT

CONFIDENCE

MEASUREMENT

CONFIDENCE

R & IR

A Solution for Patient Motion Discrete Saturation Transform (DST)

0 50% 66% 86% 97% 100%

SpOSpO2% %

Measure Through Motion Pulse Oximetry

Separating - accurate SpO2

Conventional Pulse Oximetry

0 50% 66% 86% 97% 100%

SpOSpO2% %

Averaging - inaccurate SpO2

Variable

Constant

Variable

Constant

In the presence of motion, SET separates the venous and arterial saturation values resulting in accurate saturation

readings (compared to conventional oximetry that averages the values to produce a reading)

Certainty…

Pulse Oximetry

Problems:

Accuracy

Motion & artifact

•Dyshemoglobins

• Perfusion

Carbon Monoxide (CO)

• Gas:• Colorless• Odorless• Tasteless• Nonirritating

• Leading cause of poisoning deaths worldwide!

CO: The Leading Cause of Poisoning Deaths

30-50 % of CO-exposed patients presenting to Emergency Departments are misdiagnosed

Barker MD, et al. J Pediatr. 1988;1:233-43

Barret L, et al. Clin Toxicol. 1985;23:309-13

Grace TW, et al. JAMA. 1981;246:1698-700

Show me the money…Is this real?

104 CCU admissions UAP: 3 CO toxic, 5 others minor exposure (> smoker). Balzan et al, Postgrad Med J, 1994;70:699-702

307 acute neuro admits: 3 CO toxic (all from group of 29 w/ decr. LOC absent focal s/s). Balzan et al, Postgrad Med J, 1996;72:470-3.

168 acute neuro admits: 5 CO toxic (2 from group w/ seizures) Heckerling et al, Clin Toxicol, 1990;28:29-44.

48 h/a pts: 7 COHb > 10% (14.6%, all unrelated to smoking) Heckerling et al, Am J Emer Med, 1987;5:201-4.

146 h/a pts: 4 COHb > 10% (3%, all unrelated to smoking) Heckerling et al, Ann Intern Med, 1987;107:174-6.

Up to 10% of UAP, ACS, seizure, and h/a admits

have CO poisoning

Limitations of Pulse Oximetry

Barker SJ, Tremper KK. The Effect of Carbon Monoxide Inhalation on Pulse Oximetry and Transcutaneous PO 2. Anesthesiology 1987; 66:677-679

SpCO-SpO2 Gap:

The fractional difference between actual SaO2 and display of SpO2 (2 wavelength oximetry)

in presence of carboxyhemoglobin

SpCO-SpO2 Gap:

The fractional difference between actual SaO2 and display of SpO2 (2 wavelength oximetry)

in presence of carboxyhemoglobin

From Conventional Pulse Oximeter

From invasive CO-Oximeter Blood

Sample

[Blood]

Conventional pulse oximetry can not distinguish between COHb, and O2Hb

Signs and Symptoms

SpCO% Clinical Manifestations

<5% None

5-10% Mild headache, tire easily

11-20% Moderate headache, exertional SOB

21-30% Throbbing headache, mild nausea, dizziness, fatigue, slightly impaired judgment

31-40% Severe headache, vomiting, vertigo, altered judgment

41-50% Confusion, syncope, tachycardia

51-60% Seizures, unconsciousness

Carbon Monoxide Poisoning Presents Like the Flu!

Laboratory CO-oximetry

Pulse CO-oximetry

Hgb Signatures: Physics of O2 Pathways

Red

FDA ValidationRainbow SET Compared to Reference Methodology

Noninvasive measurement provides clinically equivalent results for HbCO without invasive blood draw (+ 3% from 0 – 40%)

14,438 Patient Brown University Study

• Partridge and Jay (Rhode Island Hospital, Brown University Medical School), assessed carbon monoxide (CO) levels of 10,856 ED patients

• 11 unsuspected cases of CO Toxicity (COT) were discovered.Overall mean SpCO was 3.60%

• Occult COT was 4 in 10,000 during cold, 1 in 10,000 during warm months

• They concluded “unsuspected COT may be identified using noninvasive COHb screening and the prevalence of COT may be higher than previously recognized”

Non-Invasive Pulse CO-Oximetry Screening in the Emergency Department Identifies Occult Carbon Monoxide Toxicity. Suner S, Partridge R, Sucov A, Valente J, Chee K, Hughes A, Jay G. J Emerg Med 2008 Department of Emergency Medicine, Rhode Island Hospital, Brown Medical School, Providence, RI.

Methemoglobinemia

• Cyanotic Chemical Guardian Protocol – Health surveillance for cyanosis causing chemical handlers (pre-placement, routine, high risk assignment clearance and symptomatic workers).

Causes of Acquired Methemoglobinemia

• Soda and other foods with phenol based preservatives

• Nitrogen based fertilizers

• Nitrate laden preservatives (such as saltpeter used to cure BBQ meats)

• Infantile diarrhea (high intestinal pH promotes gram-negative organism growth, converts dietary nitrates to nitrites)

• Benzocaine & Cetacaine sprays• Dapsone• EMLA Creams• Chloroquine• Flutamide• Lidocaine• Nitrates• Nitric oxide• Nitroglycerin• Nitroprusside

Iatrogenic Causes: Others (community based):

Ash-Bernal R, et al. Acquired Methemoglobinemia A Retrospective Series of 138 Casesat 2 Teaching Hospitals. Medicine Sept 2004;83(5):265-273.

Industrial Causes:

More than 112 chemicals used

in manufacturing and finishing

plants: aniline, dinitrobenzene…

Symptoms of Methemoglobinemia

Source: David C Lee, MD, Research Director, Assistant Professor, Department of Emergency Medicine, North Shore University Hospital and New York University Medical School

SpMet% Clinical Manifestation

0-3% Normal concentration, no symptoms

3-15% Slight skin discoloration (palor, gray, or blue) may be present

15-20% Patient may be relatively asymptomatic, cyanosis likely

25-50%Headache, dyspnea, lightheadedness, weakness, confusion, palpitations, chest pain

50-70% Altered mental status, delirium

Methemoglobinemia Can Present Like the Flu!

Traditional Diagnosis of MetHb

Traditional marker: “chocolate brown” color of arterial blood

Laboratory CO-oximeter

Limitations of Pulse Oximetry

Barker SJ, Tremper KK, Hyatt J. Effects of Methemoglobinemia on Pulse Oximetry and Mixed Venous Oximetry. Anesthesiology 1989;70:112-117

[Blood]

From invasive CO-Oximeter Blood Sample

From Pulse Oximeter

The 85% SpO2 “Push”:

The difference between actual SpO2 (blue) and display

SpO2 (red) (2 wavelength oximetry) in presence of

methemoglobin

The 85% SpO2 “Push”:

The difference between actual SpO2 (blue) and display

SpO2 (red) (2 wavelength oximetry) in presence of

methemoglobin

Noninvasive Pulse CO-Oximetry

Oxygenated Hb and reduced Hb absorb different amounts of Red (RD) and Infrared (IR) Light(Two-wavelength oximeters cannot measure dyshemoglobins)

0

2

4

6

8

10

12

14

SpM

et (

%)

0 2 4 6 8 10 12 14

HbMet (%)

FDA ValidationsRainbow SET Compared to Reference Methodology

Noninvasive measurement clinically equivalent results for MetHb without invasive blood draw

Equivalent precision and accuracy (+ 1% from 0-25%)

Perfusion

Nellcor Capnoprobe™ US approval Jan 2003.

Research study: Children's Medical Center – Dallas TX.

11 kids infected Burkholderia cepacia, 2 died.

Traced to saline solution packaging of probes.

5,600 units @ 30 centers recalled

FAIL

Perfusion Index

Infrared

Saturation

Red

Infrared Signal

0.254-0.253 = 0.001

0.253- 0 = 0.253

0.001/0.253 = 0.4%

AC

DC

• Perfusion index is the ratio of the variable absorption (AC) to the non-variable (DC) of the infrared signal.

• PI display ranges from 0.02% (very weak) to 20% (very strong)

Perfusion Index

• Perfusion Index is an objective method for measuring a patient’s peripheral perfusion

• Perfusion Index is an early indicator of deterioration

Datex-Ohmeda PIr®

Range 0.3%-10%

Most Patients >0.7%

Increases the validity of the

SpO2 by locating the strongest pulse signal

Philips

Range 0.3%-10%

Optimal >1.0%

< 0.3% is marginal

reposition the site

Masimo

Range 0.02%- 20.0% Select site with highest value

Perfusion Index

• 108 healthy adults and 37 critically ill patients (finger sensors)

• PI range: 0.3% to 10%, median 1.4%

• ROC used to determine the “cutoff” value

• 1.4% PI best discriminated normal from abnormal

What is the “Normal” PI value?

Lima, et al. CCM 2002

Photoplethysmography

Abs

orpt

ion

TimeTime

R IR

Photodetector

Pleth Waveform

Pleth Waveform

Definition of PVI

• Pleth Variability Index (PVI) is a measure of dynamic changes in PI that occur during the respiratory cycle

• PVI is a percentage from 1 to 100%: 1 = no variability 100 = maximum variability

• PVI: fluid volume status

• High variability (high PVI) = volume depletion

Research on PI and PVI Ongoing…

Can we get oximetric hemoglobin?

• SpHb addedin 2008

Jan 2012: Pronto-7 (for adults > 30 kg)

• Noninvasive, quick, and accurate spot-check hemoglobin testing• Measures (Under 1 Minute)• Total Hemoglobin (g/dL, g/L, mmol/L) – SpHb (±1 g/dL at 1 SD)• Oxygen Saturation - SpO2

• Pulse Rate - PR• Perfusion Index - PI

• Touch Screen Navigation• Multiple Printing Solutions• Blue Tooth• Wireless

• Multiple Patient Reports• Stores Patient Test Information

Pronto 7 Accuracy

Frasca D et al. Crit Care Med. 39(10); 2011; 2277-2282.

Ocular Scanner

EyeMarker Systems™

Retinal imaging

Pattern recognition:•Botulism,

neurotoxins•Nerve Agents•Carbon Monoxide•CyanideFAIL

Pulse CO-Oximetry Applications

• Screening during routine exams• CO, Met, Hb baseline values• Early detection and prevention

• Urgent screening• Rapid assessment of exposed/injured workers• Triage and assessment (including PI)

• Health and safety tool• Monitoring high risk areas/workers

Questions?

mikemcevoy.com