Introduction to the use of Pulse Oximeter in PAM by gregorio11




1.     Prior to the advent of pulse oximeter, a paramedic evaluates a patient's
state of oxygentation by direct observations of the rate and quality of breathing,
apparent degree of respiratory distress, colour of mucous membranes and
quality of breath sounds. Adverse field environments such as poor lighting,
high noise levels and excessive movement/vibration can degrade the accuracy
of these traditional methods. Pulse Oximetry, which is not subjected to such
limitations, is a valued tool in casualty management. An advisory, which
explains the use of pulse oximeter in the Patient Assessment Model (PAM) is


2.     Pulse oximeter measures the percentage of hemoglobin in the arterial
blood that is saturated with oxygen (Spo2). Oxygenated blood is bright red
while deoxygenated blood is of a darker, red-blue shade. The Pulse Oximeter,
which uses a light-emitting diode (LED) to transmit light through the vascular
bed, measures the colour difference to determine the oxygen saturation of
arterial blood. To ensure that it is measuring arterial blood and not venous
oxygen saturation, the pulse oximeter is designed to detect only pulsating blood


3.    Pulse oximetry has the following applications in pre-hospital emergency

      a.    Assessment of oxygenation level during triage.
      b.    Identification of patient with airway or respiratory problems.
      c.    Continuous monitoring of oxygenation and heart rate in unstable
      d.    Assessment of vascular status of injured limbs.

4.    Pulse Oximetry is useful for the primary survey of casualty in field
environment. It can be used as an adjunct evaluation tool with other physical
examination for medical problems related to level of consciousness (LOC),
airway patency, breathing difficulty/insufficiency, circulation inadequacy
(shock) and major/multiple trauma. In the Patient Assessment Model (PAM),
pulse oximeter can be applied during the following stages:
      a. 'LOC' (Level of Consciousness) - when casualty has altered level of
      b. 'B' (Breathing) - when casualty shows signs of respiratory distress.
      c. 'RBS' (Rapid Body Survey) & 'SOAP' (Skin, Oxygen, Airway and
      Position) - use to initiate baseline reading as a fifth vital sign or if
      casualty sustained major/multiple trauma injuries and/or show any signs
      of shock.

5.    Patients with signs and symptoms of respiratory distress or insufficiency
should receive oxygen irrespective of pulse oximeter reading (if available).
This allows the rescuer to monitor the adequacy of arterial oxyhemoglobin
saturation and to confirm the effectiveness of the ventilatory support. The pulse
oximeter could be applied as early as the 'LOC' stage so that Spo 2 reading could
be obtained together with direct observations of the patient's rate and quality of
breathing, apparent degree of respiratory distress, colour of patient's mucous
membranes and quality of breath sounds.


6.    Turn on the unit, place the sensor on patient's finger. While waiting for
display to come on, medic should continue to complete the primary survey. If
reading does not appear and/or error message appeared, move the sensor to
another finger. The rescuer should note that clinical assessment, critical
intervention and undelayed transportation would have priority over attempts to
reapply the pulse oximeter.


7.    Beware of the following situations, where false readings may be possible:

      a.   Hb saturation with compounds other than O2 (e.g. carbon
      monoxide poisoning or smoke inhalation)
      b.   Excessive ambient light on the sensor
      c.   Patient movement
      d.   Hypotension
      e.   Hypothermia and vasoconstriction
      f.  Use of nail polish
      g.   Jaundice
      h.  Venous pulsation in patients with right heart failure

8.    When in doubt, look at the patient. If the patient is turning blue and
struggling to breathe, ignore the pulse oximeter reading which indicate the
patient is adequately oxygenated.

9.   The lower normal range for Spo2 is 95%. The upper range is 99% to
100%. Oxygen should be provided for Spo2 reading < 95%.


10. Pulse oximetry, when available, should not be used alone to determine
the state of ventilatory well-being. In the field, over reliance on pulse oximetry
may lead to delays in other life-saving intervention. Casualty showing signs of
airway obstruction, tension pneumothorax or haemorrhage must be managed
and not delay by attempts to apply pulse oximetry. When pulse oximetry shows
adnormal reading, the medic must reassess the casualty immediately. The PAM
Table and Pulse Oximeter flow-chart, which further explain the use of pulse
oximetery in PAM are in Annexes A & B.

                                        Patient Assessment Model (PAM)
   Primary           Action(s)                    For SAF – Only One Medic                      More than One medic
   Survey                                                                                       or when an assistant is
Rescue Scene Evaluate:
Evaluation(RS 1. Environment
E)            2. Potential Hazards
              3. Mechanism of
Level of      Check LOC using          Apply pulse oximeter for casualty with altered           Assistant helps to apply
Consciousness AVPU                    level of consciousness or in doubt                        the pulse oximeter
D-Spine         Check for signs of
                spinal injury
A - Airway      Check for patency of Attach pulse oximeter if not yet applied.                  Assistant starts BVM
                airway                                                                          with oxygen at 15 l/min
                                     If casualty shows sign of respiratory distress and /       if casualty shows sign
B - Breathing   Check for rate &
                                     or SpO2 < 95%, medic starts O2 with non-                   of respiratory distress
                quality of breathing
                                     rebreather mask at 15 l/min and continues to               and SpO2 < 95%, while
                                     complete the primary survey.                               the crew leader
                                                                                                continues to complete
                                      Note: However, if casualty shows sign of apnea or         the primary survey
                                      poor respiratory effort, medic should covert the
                                      non-rebreather mask to Bag-mask with 100%
                                      oxygen at 15 l/min immediately after completing
                                      the RBS and any critical interventions.
C - Circulation Check for rate and    Pulse rate can be measured by the pulse oximeter, however, physical
                quality of pulse      palpation is still required to assess the quality of the pulse i.e., weak, strong,
                                      regular or irregularity of pulse rate.
RBS - Rapid     1. Rapid look and     Pulse oximeter can be applied at this stage to initiate baseline reading as a
Body Survey     check for any major   fifth vital sign.
                bleeding or injury
                from Head-to-Toe      Crtical Intervention (if indicated):
                                      1. Open airway & cervicle spine control
                                      2. bag-mask with 100% oxygen
                                      3. stop major bleeds
SOAP – Skin, 1. Assess skin           1. Check the reading from pulse oximeter if already Check the reading from
O2, Airway & colour & patient         applied.                                              pulse oximeter if
Positioning  condition                                                                      already applied
                                      2. If the reading is SpO2 < 95% and casualty
                2. Give O2 if         continues to show sign of respiratory distress, medic Check oxygen flow rate
                available, at         should initiate BVM with O2 resuscitator and high if available
                appropriate flow rate flow of oxygen(15 L/min) if not applied yet.
                or use BVM as
                appropriate.          3. If the reading is >95% and no signs of
                                      respiratory distress, no need for oxygen. However,
                3. Put casualty in    medic can still consider to give Oxygen using O2
                optimal position.     Resuscitator & Simple Face Mask at a flow rate of 6
                                      to 10 L/min for casualty after strenous exercise.
                4. Attach pulse
                oximeter & check      4. Prepare for transportation
                reading if not yet
                                          Patient Assessment Model (PAM)
Decision Point                                        Load & go or stay & treat
Protocol,            Use appropriate protocol based on casualty's condition. Decide on the urgency of evacuation
Documentatio           Evacuation should take precedence over documentation if casualty's condition is critical.
n prior to
  Secondary            Action(s)                    For SAF – Only One Medic                  More than One medic
   Survey                                                                                     or when an assistant is
Vital Signs       1. LOC (using GCS) Attach pulse oximeter (if not yet applied) / check reading(if already in place)
                  2. Respiration
                  3. Pulse
                  4. Skin
                  5. BP(if available)
Head To Toe                                      Systematic Head to Toe examination
History Taking                                                 1. Event
(if applicable)                                    2. Medical History & Medication
                                                             3. Allergies

                   Apply Pulse Oximeter
                    on Casualty's finger

Spo2 <95%                                       Spo2 >95%

                                             Are there any signs of:
Administer                          Yes      1. Altered conciousness
 Oxygen                                      2. Respiratory insufficiency
                                             3. Shock
                                             4. Major/multiple trauma


                                           Oxygen not required


                                                 Continue to
             Yes        Is Spo2               monitor the pulse
                        <95%?                 oximetry reading

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