Overcoming the challenge of monitoring SpO2 in critically ill

patients

N GRAVENSTEIN MD5/21/19

Disclosure

I am a consultant for Philips.

Learning outcomes

1. Describe nasal ala pulse oximetry and its significant advantages by measuring oxygen saturation at the nasal ala.a) Describe how pulse oximetry works.b) Describe the rationale for pulse oximetry at the nasal ala site.c) Describe the advantages of nasal alar pulse oximetry.

2. Demonstrate how to use the nasal alar SpO2 sensor technology properly. a) Demonstrate how to use the nasal ala site for pulse oximetry. b) Demonstrate how to be a better SpO2 resource for your patients and others.

Who are we talking about?

We all have had patients where getting SpO2 is difficult

https://www.researchgate.net/publication/6535240_Acute_Deep_Hand_Burns_Covered_by_a_Pocket_Flap-Graft

https://www.jeffreysterlingmd.com/2016/01/20/straight-no-chaser-the-dos-and-donts-of-treating-frostbite-2/

How does SpO2 work?

Two LEDs One photodetector Photoplethysmogram Peak light absorption

detection Ratio red/infrared Adequate signal-to-noise

ratio Software lookup table for

saturation Display SpO2 value

A tiny % of the light picked up by the sensor represents the SpO2 signal for the monitor?

Sensor site composite of dynamic and static components affecting light absorption

Time

ABSO

RPT

ION • Absorption due to arterial blood

Absorption due to tissue

• Absorption due to venous blood

• Variable absorption due to pulse-added volume of arterial blood

common mistakes with pulse oximeters

https://opentextbc.ca/vitalsign/chapter/why-is-pulse-oximetry-used/

Good clinical practice tip

When looking at SpO2 think See pleth before O2

How equipment works.com

Troubleshooting your pulse oximeter

is the patient alive? is the patient in a low perfusion state? are the emitters and detector aligned? is there bright ambient light? does the sensor have power?

start with your patient and work your way back to the monitor

Pulse oximetry perfusion index

use the best finger!

Sample application

Sample application

It’s all about pulsatile blood flow

Low finger pulsatile blood flow

Local vasoconstriction (ie drug, temperature) Critical illness (i.e., low cardiac output) Low blood pressure VAD

Thermal image (healthy adult in cold room)

1-2 minutes

45 minutes

Thermal image (healthy adult in cold room)

Thermal image (healthy adult in cold room)

1-2 minutes 45 minutes

Infrared thermometry demo

Vasoconstrictive distal ischemia

Presenter

Presentation Notes

AKA the ala maneuver

Nasal alar pulse oximetry sensor

Protected circulation areas

What in the world is an ala?

Internal carotid branch

External carotid branch

Blood supply to the ala

• The nasal ala has little sympathetic innervation

courtesy of richard melker

The nasal alar vasculature responds differently to vasopressors

What's different about the ala probe?

same technology as finger probe same algorithm same waveform bigger signal to noise ratio (AKA perf or perfusion index) different applicator self-retaining

Nasal alar sensor application

Apply with T-shaped pad and wire on outside of ala

Ala is back part of nose, closest to cheek

Remove applicator

Position sensor fully on to ala Secure sensor; Check

or rotate site periodically

BENEFITS

BIGGER signal (with protected circulation, higher perfusion index) FASTER responses than a finger sensor to declining SpO2

FASTER feedback that an intervention is having desired effect BETTER performance in low peripheral perfusion states

Response time and signal size demo

Questions?

How many things can you learn from a pulse oximeter?

How many things can you learn from a pulse oximeter?

1 - O2 sat2 - Heart rate3 - Heart rhythm4 - If sat changing5 - If heart rate changing6 - Systolic bp7 - Hypovolemia8 - If patient alive9 - If CPR is making an effective pulse

At least 9