Monitoring devices such as pulse oximetry and inspired and expired gas monitoring are used to monitor a patient's oxygen saturation, respiratory rate, and end-tidal carbon dioxide levels. Pulse oximetry uses light absorption to noninvasively measure oxygen saturation and heart rate, while capnography monitors end-tidal carbon dioxide levels via mainstream or sidestream methods. Blood gas analysis directly measures pH, PCO2, PO2, and HCO3 levels in arterial blood to evaluate respiratory and metabolic function.

1. MONITORING
DEVICES :
PULSE OXIMETRY
INSPIRED AND EXPIRED GAS
MONITORING
PRESENTED BY : ALEENA GIGI
MODERATED BY : MS. APOORVA H SHETTY

2. OBJECTIVE
1. DEFINITION
2. PRINCIPLE
3. PURPOSE
4. ERRORS
5. ADVANTAGES AND DISADVANTAGES
6. COMPLICATION

3. WHAT IS MONITORING ?
Monitoring generally means to be aware of the state of a system, to
observe a situation for any changes which may occur over time, using
a monitor or measuring device of some sort .

4. WHY MONITOR ?
Disturbances can occur during surgery, they include but are
not limited to :
. Airway obstruction, Respiratory depression, Apnea .
. Cardiac depression, Arrhythmias, Bradycardia, Tachycardia .
. Hypertension, Hypotension, Hypervolemia, Hypovolemia, Fluid shifts .
. Hypothermia, Hyperthermia .

5. PULSE OXIMETRY
DEFINITION
A Pulse Oximeter is a device that is used to quickly and easily
monitor a person’s oxygen saturation .
It can measure the level of oxygen within the blood, specifically
in arterial blood without using any invasive means .
In addition to measuring oxygen saturation, the device provides
a heart rate measurement as well.

6. OXIMETERS CONSISTS OF :
• Peripheral probe
• A microprocessor unit displays a waveform – the oxygen
saturation and the pulse rate .
• Red and infrared light emitters detector .
• Most oximeters also have an audible pulse tone .

7. PURPOSES :
• Pulse oximeters measure the arterial oxygen saturation of
haemoglobin .
• To relieve cyanosis by detecting hypoxia and severe respiratory
failure .
• It measures the pulse rate in beats per minute .

8. WORKING PRINCIPLE :
• Pulse oximeter works on the principle of Beer-Lambert’s Law .
• It is based on the red and infrared light absorption characteristics of
oxygenated and deoxygenated haemoglobin.
• Red light is in the 600-750 nm wavelength light band and Infrared light is
in the 850-1000 nm wavelength light band .
• Pulse oximetry works by placing a pulsating arteriolar vascular bed
between a dual light (red and infrared) source and a photodetector .

9. • The photodetector records the relative amount of each
colour absorbed by arterial blood and transmits the data to a
monitor, which displays the information with each heartbeat .
• Oxygenated haemoglobin absorbs the infrared light more
than red light and the deoxygenated haemoglobin absorbs
more red light than infrared light .
• A healthy person has saturation level ranging from 95 to 99
percent.

10. GENERALLY MEASURED ON :
• The finger
• Toe
• Pinna (top) or lobe of the ear
• Infants – The bridge of the nose, foot, palm of the hand, the big toe
or the thumb .

11. ERRORS :
• Abnormal haemoglobins:
Carboxyhemoglobinemia – Carbon monoxide has the same absorption
pattern of red light such as oxygenated hemoglobin, therefore will overestimate
the real value .
Methemoglobinemia – Shows fix saturation of 85% .

12. • Anaemia – Severe anaemia causes underestimation of actual values .
• Hypovolemia and Vasoconstriction (especially in cold) – Difficulty in
obtaining actual values and false low SpO2 reading .
• Vasodilatation – Slight decrease .
• Nail polish (especially blue colour) – Impairs the transmission of light
therefore shows false reading .

13. • Shivering – Constant movement of finger impairs continuous
transmission of light and hence false reading .
• Skin pigmentation – Theoretically dark pigmentation can also
impair the transmission of light .

14. INSPIRED AND EXPIRED GAS MONITORING
CAPNOGRAPHY :
• It is the continuous measurement of end tidal (expired)
carbon dioxide (ETCO2) along with its waveform .
• Capnography is the monitoring of the concentration of
partial pressure of CO2 in the respiratory gases .
• It is mainly used as a monitoring tool for use during
anaesthesia to confirm intubation and intensive care .

15. METHODS OF MONITORING:
CO2 monitors measure gas concentration, or
partial pressure using one of two configurations :
• MAINSTREAM
Mainstream devices measure respiratory gas
(CO2) directly from the airway, with the sensor
located on the airway adapter at the hub of the
ETT.

16. ADVANTAGES:
1. No sampling tube to become obstructed .
2. No variation due to barometric pressure changes .
3. No variation due to humidity changes .
4. Direct measurement means waveform and readout are in ‘real-time’ .
There is no sampling delay .
5. Suitable for pediatrics and neonates .

17. DISADVANTAGES:
1. The airway adapter sensor puts weight at the end of the ETT and thus
often needs to be supported .
2. In older models there were minor burn reported .
3. The sensor windows can become obstructed with secretions and water
rainout .
4. Sensor and airway adapter can be positional difficult to use in unusual
positions (prone, etc.)

18. • SIDESTREAM
Sidestream devices measure
respiratory gas via nasal or nasal-
oral cannula by aspirating a small
sample from the exhaled breath
through the cannula tubing to a
sensor located inside the monitor .

19. ADVANTAGES:
1. Sampling capillary tube and airway adapter is easy to connect .
2. Single patient use sampling – no issue with sterilization .
3. Can be used in patients with almost any position (prone, supine, etc.) .
4. Can be used on awake patients via a special nasal cannula .
5. CO2 reading is unaffected O2 flow through the nasal cannula .

20. DISADVANTAGES:
1. The sampling capillary tube can easily become obstructed by H2O or
secretions .
2. Water vapour pressure changes within the sampling tube can affect CO2
measurement .
3. Waveforms of children are often not clear or deformed .
4. Delay in waveform and readout due to the time it takes the gas sample
to travel to the sensor within the unit .

21. CAPNOGRAPHY VALUES
NORMAL VALUE - 35 TO 45 mmhg
HYPOVENTILATION - > 45 mmhg
HYPERVENTILATION - < 35 mmhg

22. WORKING MECHANISM:
• Capnographs usually work on the principle that CO2 absorbs
infrared radiation . A beam of infrared light is passed across the gas
sample to fall on a sensor .
• The presence of CO2 in the gas leads to a reduction in the amount
of light falling on the sensor, which changes the voltage in a circuit .
• The analysis is rapid and accurate .

24. ABNORMAL CAPNOGRAPHY

26. The oxygen analyser is a device with an oxygen sensor intended to
measure the percentage of oxygen in the gas or gas mixture
delivered to the patient .
OXYGEN ANALYSER

27. • The oxygen analyser is positioned within the fresh gas flow of the
breathing system.
• It is fitted in the inspiratory limb of the circle system .
• It will detect disconnection of the breathing system from the
anaesthetic machine and also any failure of the oxygen supply.
• Some machines are fitted with an audible alarm, that is activated if
the oxygen pressure falls below a lower limit.

28. WORKING
• An oxygen analyser contains an oxygen sensor which reacts with
the oxygen in the atmosphere or gas stream.
• The oxygen sensor will produce a small electrical current that is
proportional to level of oxygen it is reacting with.
• The oxygen analyser converts the current to percent oxygen level,
which is then displayed on the oxygen analyser's screen or used to
activate process alarms.

29. USES
• Measure percentage of oxygen.
• It is used to monitor trace gases in the OR.
• Measures oxygen output in anaesthesia machine and ventilator.
• It helps in the continuous administration of oxygen with alarm.
• It measures the final delivered concentration of oxygen to the
patient (in closed circuit).

30. VENTILATOR PARAMETERS
1. TIDAL VOLUME:
The volume of gas set to be delivered to the lungs by the ventilator with
each breath.
2. RESPIRATORY RATE:
The set number of breaths delivered by the ventilator per minute.
3. MINUTE VENTILATION (Total Ventilation):
It is a measurement of the amount of air that enters the lungs per minute.
Minute Ventilation = Respiratory Rate (RR) x Tidal Volume (Vt)

31. 4. PEAK INSPIRATORY PRESSURE (PIP):
It is the highest level of pressure applied to the lungs during inhalation.
PIP normal range – greater than 50cm H2O .
5. PLATEAU PRESSURE:
It is the pressure applied to small airways and alveoli during positive-
pressure mechanical ventilation.
Ideally, plateau pressure should remain under 30cm H2O.

32. 6. I:E RATIO :
I – Inspiratory , E – Expiratory .
It denotes the proportions of each breath cycle devoted to the
inspiratory and expiratory phases. The total time of a respiratory cycle
is determined by dividing 60 seconds by the respiratory rate.
Normal I:E Ratio is 1:2

33. 7. Fio2 :
The fraction of inspired oxygen (Fio2) is the concentration of oxygen in the
gas mixture .
Natural air includes 21% oxygen, which is equivalent to FiO2 of 0.21.
8. POSITIVE END-EXPIRATORY PRESSURE (PEEP) :
It is the alveolar pressure above atmospheric pressure that exists at the end
of expiration.
Value – from 5 upto 25 cmH2O .

34. BLOOD GAS ANALYSIS
DEFINITION:
It is a diagnostic procedure in which blood is obtained from an artery
directly by an arterial puncture or accessed by a way of indwelling
arterial catheter .

35. INDICATION:
• Respiratory failure
• Ventilated patient
• Cardiac failure
• Renal failure
• Sepsis and Burn
• Poisoning

36. SITES FOR
OBTAINING ABG
• RADIALARTERY(most
common)
• BRACHIALARTERY
• FEMORALARTERY
• DORSALIS PEDIS
• POSTERIOR TIBIAL
ARTERY

37. Radial is the most preferable site used because :
• It is easy to access.
• It is not a deep artery which facilitate palpation, stabilization and
puncturing .
• The artery has a collateral blood circulation .

38. ALLEN’S TEST
It is a test done to determine that collateral circulation is present from
the ulnar artery in case thrombosis occur in the radial .

39. ABG COMPONENT
• PH :
measures hydrogen ion concentration in the blood, it shows blood’s acidity or
alkalinity.
• PCO2 :
It is the partial pressure of CO2 that is carried by the blood for excretion by the
lungs, known as respiratory parameter .

40. • PO2 :
It is the partial pressure of O2 that is dissolved in the blood, it reflects
the body’s ability to pick up oxygen from the lungs .
• HCO3 :
Known as the metabolic parameter, it reflects the kidney’s ability to
retain and excrete bicarbonate .

41. NORMAL VALUES :
• PH = 7.35 – 7.45
• PCO2 = 35 – 45 mmhg
• PO2 = 80 – 100 mmhg
• HCO3 = 22 – 28 meq/L

42. EQUIPMENT
• Blood Gas Kit OR
. 1ml / 2ml syringe . Plastic bag and Crushed ice
. 23 – 26 gauge needle . Lidocaine (optional)
. Stopper . Vial of heparin ( 1:1000 )
. Alcohol swab . Par code or label
. Disposable gloves

43. PROCEDURE:
• Wash hands and wear gloves .
• Place pillow under patient’s wrist .
• Palpate the artery, i.e radial, brachial or femoral to be punctured .
• Obliterate both radial and ulnar arteries at wrist by pressing them
with both thumbs .
• Ask the patient to clench and unclench the fist until blanching of
skin occurs .

44. • Release the pressure on the ulnar artery by removing the thumb on
it .
• Watch the return of circulation to skin within 15 sec .
• Palpate the radial artery for pulsation .
• Puncture the artery at 45-60 degree angle .
• The arterial blood rushes into the syringe with a great force .
• We should withdraw 2-3 ml of blood for sample .

45. • Once the sample has been taken, withdraw the needle and apply
firm pressure over the site of puncture with dry sponge .
• Remove the air bubble from syringe and needle .
• Place the capped syringe into an ice container .
• Maintain firm pressure on puncture site for 5 min .
• If patient is on anticoagulants use the high pressure dressing .
• Assess for cold hands or numbness .

46. CONTRAINDICATION:
• Coagulopathy
• Atherosclerosis
• Infection at insertion site
• Use of thrombolytic agent

47. COMPLICATIONS:
• Local pain
• Arteriospasm
• Hematoma
• Hemorrhage
• Distal ischemia
• Infection
• Numbness