Non-Invasive Safety and
Wellness Technologies
Mike McEvoy, PhD, NRP, RN, CCRN
Sr. Staff RN – Cardiothoracic Surgery
Chair – Resuscitation Committee – Albany Med Ctr
EMS Coordinator – Saratoga County, New York
EMS Editor – Fire Engineering magazine
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?
Pulse Oximetry
Problems:
• Accuracy
• Motion & artifact
• Dyshemoglobins
• Perfusion
Oxygenation
• Pulse Oximetry
Oxygenation
• Pulse Oximetry
Model of Light Absorption At Measurement
Site Without Motion
Absorption
AC Variable light absorption due
pulsatile volume of arterial blood
DC Constant light absorption due to
non-pulsatile arterial blood.
DC Constant light absorption due to
venous blood.
Time
DC Constant light absorption due to
tissue, bone, ...
Model of Light Absorption At Measurement
Site With Motion
Absorption
AC Variable light absorption due
pulsatile volume of arterial blood
DC Constant light absorption due to
non-pulsatile arterial blood.
AC Variable light absorption due to
moving venous blood
Time
DC Constant light absorption due to
venous blood.
DC Constant light absorption due to
tissue, bone ...
Influence of Perfusion on Accuracy of
Conventional Pulse Oximetry During Motion
Good Perfusion (Conventional PO)
SpaO2=98
SpvO2=88
SpO2=93
Poor Perfusion (Conventional PO)
SpaO2=98
SpvO2=50
SpO2=74
Conventional Pulse Oximetry Algorithm
R & IR
Digitized,
Filtered &
Normalized
MEASUREMENT
R/IR
CONFIDENCE
Post
Processor
% Saturation
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
R/IR
(Conventional Pulse
Oximetry)
MEASUREMENT
CONFIDENCE
MEASUREMENT
DSTTM
R & IR
Digitized,
Filtered &
Normalized
CONFIDENCE
MEASUREMENT
FSTTM
CONFIDENCE
Confidence
Based
Arbitrator
Post
Processor
% Saturation
DST
SET – 97%
MEASUREMENT
SSTTM
CONFIDENCE
0
MEASUREMENT
Proprietary
Algorithm 4
CONFIDENCE
Masimo SET “Parallel Engines”
SET “Parallel Engines”
50%
66% 97% 100%
SpO2%
A Solution for Patient Motion
Discrete Saturation Transform (DST)
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)
Variable
Constant
Variable
Averaging inaccurate SpO2
0
50%
66%
86%
Constant
97% 100%
SpO2%
Conventional Pulse
Oximetry
0
50%
Separating accurate SpO2
66%
86%
97%
100%
SpO2%
Measure Through
Motion Pulse Oximetry
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
Up to 10% of UAP, ACS,
seizure,
and
h/a
admits
 168 acute neuro admits: 5 CO toxic (2 from group w/ seizures)
CO poisoning
Heckerling et al,have
Clin Toxicol, 1990;28:29-44.
 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.
 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.
Limitations of Pulse Oximetry
Conventional pulse oximetry can not distinguish between COHb, and O2Hb
From Conventional
Pulse Oximeter
SpCO-SpO2 Gap:
The fractional difference between
actual SaO2 and display of SpO2
(2 wavelength oximetry) in
presence of carboxyhemoglobin
From invasive COOximeter Blood
Sample
[Blood]
Barker SJ, Tremper KK. The Effect of Carbon Monoxide Inhalation on Pulse Oximetry and Transcutaneous PO 2. Anesthesiology 1987; 66:677-679
Signs and Symptoms
SpCO%
<5%
Clinical Manifestations
None
5-10%
Mild headache, tire easily
11-20%
Moderate headache, exertional SOB
21-30%
41-50%
Throbbing headache, mild nausea,
dizziness, fatigue, slightly impaired
judgment
Severe headache, vomiting, vertigo,
altered judgment
Confusion, syncope, tachycardia
51-60%
Seizures, unconsciousness
31-40%
Carbon Monoxide Poisoning Presents Like the Flu!
Laboratory CO-oximetry
Pulse CO-oximetry
Hgb Signatures: Physics of O2 Pathways
FDA Validation
Rainbow SET Compared to Reference Methodology
Noninvasive measurement provides clinically equivalent results for
HbCORed
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
Iatrogenic Causes:
•
•
•
•
•
•
•
•
•
•
Benzocaine & Cetacaine sprays
Dapsone
EMLA Creams
Chloroquine
Flutamide
Lidocaine
Nitrates
Nitric oxide
Nitroglycerin
Nitroprusside
Ash-Bernal R, et al. Acquired Methemoglobinemia A Retrospective Series of 138 Cases
at 2 Teaching Hospitals. Medicine Sept 2004;83(5):265-273.
Others (community based):
• 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)
Symptoms of Methemoglobinemia
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!
Source: David C Lee, MD, Research Director, Assistant Professor, Department of Emergency Medicine, North Shore
University Hospital and New York University Medical School
Traditional Diagnosis of MetHb
Traditional marker: “chocolate
brown” color of arterial blood
Laboratory CO-oximeter
Limitations of Pulse Oximetry
From Pulse
Oximeter
The 85% SpO2 “Push”:
The difference between
actual SpO2 (blue) and display
SpO2 (red) (2 wavelength
oximetry) in presence of
methemoglobin
From invasive
CO-Oximeter
Blood Sample
[Blood]
Barker SJ, Tremper KK, Hyatt J. Effects of Methemoglobinemia on Pulse Oximetry and Mixed Venous Oximetry. Anesthesiology 1989;70:112-117
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)
FDA Validations
Rainbow SET Compared to Reference Methodology
14
12
SpMet (%)
10
8
6
4
2
0
0
2
4
6
8
10
12
14
HbMet (%)
Noninvasive measurement clinically equivalent results for
MetHb without invasive blood draw
Equivalent precision and accuracy (+ 1% from 0-25%)
Perfusion
Nellcor Capnoprobe™
l
US approval Jan 2003.
l
Research study: Children's
Medical Center – Dallas TX.
l
11 kids infected Burkholderia
cepacia, 2 died.
l
Traced to saline solution
packaging of probes.
l
5,600 units @ 30 centers
recalled
Perfusion Index
Saturation
Infrared
Red
Infrared Signal
• Perfusion index is the ratio of the variable absorption
(AC) to the non-variable (DC) of the infrared signal.
0.254-0.253 = 0.001
0.253- 0 = 0.253
AC
DC
0.001/0.253 = 0.4%
• 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%
Perfusion Index
Select site with highest value
What is the “Normal” PI value?
• 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
Lima, et al. CCM 2002
R IR
Absorption
Photoplethysmography
Pleth Waveform
Photodetector
Time
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 added
in 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
• Cyanide
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