Basic anaethetic monitoring

1. BASIC ANESTHETIC MONITORING
PRESENTED BY:Dr.ANIL BABU(ASSISTANT PROFESSOR)
DEPARTMENT OF ANAESTHESIAOLOGY

3. BASIC ANESTHETIC MONITORING
• The primary goal of anesthetic monitorings to keep the patient as safe
as possible in the perioperative world.
• Anesthesia and surgery are serious invasions on the physiologic
stability on the human body.
• Careful monitoring of the patient during and after surgery allows the
anaesthesiologist to identify problems early, when they can still be
corrected.

4. Proper monitoring of the patient can reduce the risks involved in
anaesthesia and surgery.

5. GOALS OF ANESTHESIA
Some of the physiologic disturbances that include the peri operative
period include:
• Apnea,
• Respiratory depression,
• Airway obstruction,
• Cardiac depression,
• Hypertension & Hypotension,
• Hypovolemia
• . Arrhythimias,

6. •
• Blood loss,Fluid shifts,Weakness,
• Bradycardia and Tachycardia ,
• Hypothermia and Hyperthermia .

7. STANDARDS OF CARE
• Proper monitoring standards are well defined.Federal and state
governments ,as well as national and local groups all have tried to set
guidelines tor standards.(Guidelines specific what is usually expected
and standards specific what is always expected.)
• The most widely accepted current anaesthesia monitoring Standards
that those that have been published by the American Society of
Anaesthesialogists(ASA).
• The most part , monitoring standards are not law(expections include
New Jersey and New York).but for all practical purposes they might
as well be.

8. • Failure to follow nationally published standards sets the practioner up
for credentialings, problems,lawsuits and the like.
• The ASA standards are published in the 1986 and were most recently
updated in 1993.
• Copies of the ASA standards for monitoring are available from the
ASA.

9. ASA STANDARDS FOR BASIC ANESTHETIC
MONITORING
• Standard 1 states that a qualified anaesthesia provider will be present
with the patient throughout the anesthetic.
• Standard 11 states that the patient oxygenation, ventilation,
circulation,and temperature Will continually monitored.
Assessment of oxygenation involves two parts:
Measurement of inspired gas with a oxygen analyser and
assessment of haemoglobin saturation with a pulse oximeter and
observation of skin colour.
Assessment of ventilation :
By clinical assessment and preferably Capnography.

10. • Tracheal intubation must be verified clinically and detection of
exhaled CO2.
• Mechanical ventilation must be monitored with an audible disconnect
monitor.
Assessment of circulation involves:
Continuous ECG monitoring,and blood pressure measurements
For every five minutes continuous monitoring of peripheral circulation
such as palpation,ausculation,plethysmography or arterial pressure
monitoring.

11. • The patient temperature must be measured if changes are
anticipated,intended or suspected.

12. MONITORING DEVICES
Oxygen analysers
• Oxygen analysers are the integral part of the newer anaesthesia
machines and have been added onto the most of the older machines.
• The purpose of the oxygen analyser is to confirm That oxygen is being
delivered to the patient and concentration of oxygen in the gas
mixture is adequate.
• Isolated incidents have occurred where the gas in the hospital ‘green
line’was argon or something else other then oxygen.
• The oxygen analysers provides one last check before the gas mixture
is delivered to the patient.

13. • Current anesthesia machines also have over pressure alarms and over
pressure ‘pop off’ values.
• Patient injury can occur before these high pressure alarms are
triggered.
• For the analyse to be useful it must be calculated and the low limit
alarm must be working.

14. OXYGEN ANALYSERS
• There are two types of oxygen analysers are:
. Galvanic (Fuel cell)
The Polargraphic
• The systems we use are the polograhic.
• This involves a semipermeable membrane,an electrolyte solution,and
battery source.
• The battery polarizes the electodes,and the current that is generated varies
with the amount of oxygen present.

15. • The electrode/electrolyte
catridge requires periodic
replacement.
• The main disadvantage of this
system is the slow response
time.

16. AUTOMATIC BLOOD PRESSURE MONITORS
• Current automatic non-invasive blood pressure monitor s work on the
oscillometric technique.
• The cuff inflates above the systemic pressure and then deflates
slowly.
• The monitor first senses oscillates as the cuff drops to systolic
pressure.
• The point at which the oscillates are the strongest is the read as the
mean pressure.
• Most of these devices calculate the diastolic pressure after they the
systolic and mean pressure.

17. • The system is normal very reliable
and accurate,but motion(especially
shivering)on the part of the patient
or the surgeon leaning against the
cuff will cause false readings or
failure to get reading .
• Patient injury is possible if the
tubing becomes kinked.Values may
be in error if the cuff is not in the
proper size.

18. VENTILATION MONITORS
• Current anesthesia machines have ventilator disconnect alarms and
builts in spirometers.
• The spirometers have high and low limit alarm settings.
• Continuous measurement of exhaled tidal volume can detect circuit
leaks and hypoventilation.
• The spirometers on the anesthesia machines may give false readings
if moisture blocks the inner workings.

21. 1. CARDIOVASCULAR
MONITORING

24. ECG MONITORS
• The ECG monitor can provide a lot of information to the
anaesthesiologist.
• Arrhythmias detection and identification of bradycardia and
tachycardia are important uses.
• The ECG monitor may also provide first indication of myocardial
ischaemia.
• However the absence of ST depression doesn’t guarantee the
ischaemia is not present.
• Lead placement is important in ischaemia detection.

25. • The most sensitive lead is lead
V5,detecting about 75 percentage
of ischaemic episodes.
• Lead 2 plus lead V5 raise the
detection rate to 80
percent,whereas lead 2,lead
V4,lead V5 together detect 95
percent of ischaemic events.
• Current top of the line monitors do
automated ST analysis which is
more reliable than individual
practioner assessment as long as
the measurement points are
correct.

26. ECG
• Arrhyhimia-Lead 11.
• Ischaemia-Lead V.
• Cardiac arrest.

29. TRANSESOPHAGEAL ECHO CARDIOGRAHY
Most sensitive to detect any wall
motion abnormality
• Ischaemia
• Valvular dysfunction
• Air embolism

31. IBP
• Required in patients mandates in beat to beat monitoring.
• Gold standard
• Accuracy(measure the difference in IBP and NIBP not more than 5_8
mmHg.
• Radial artery
• Brachial artery
• Femoral artery
• Dorsal pedis artery.

32. CENTRAL VENOUS PRESSURE MONITORING

33. INDICATIONS
• Major surgeries in hemodynamics are expected.
• Open heart surgeries.
• Fluid loss management in shock.
• Venous access.
• Parentral nutrition.
• Aspiration of air embolus and
• Cardiac pacing.

34. CVP INCREASED IN:
• Fluid overloading
• Congestive cardiac failure.
• Pulmonary embolism.
• IPPV with PEEP.
• Pleural effusion.
• Haemothorax .
• Coughing and straining

35. CVP DECREASED IN:
• Hypovolemia and shock
• Venodilator.
• Spinal/Epidural anaesthesia.
• General anesthesia-by causing vasodilation.
Low CVP+ Low BP=Hypovolemia
High CVP+High BP=Pump failure

36. PULMONARY ARTERY
CATHETERIZATION

37. PULMONARY ARTERY CATHETERIZATION
• -It is reserved for only fir very major cases in severely compromised
patients because cost, feasibility, complications.
• Swan Ganz catheter –It is balloon tipped and flow directed by
pressure tracing, pressure recordingand catheter top.
• Indicated in sudden rise in diastolic pressure.

38. PULMONARY ARTERY CATHETER

39. Swan _Ganz Catheter (Pulmonary artery
catheterization)
• Provides diagnostic information
to rapidly determine
hemodynamic pressure, cardiac
output, and for various mixed
venous oxygen saturation.
Measures
• CVP
• PAP
• Cardiac Op

40. INDICATIONS
• Post MI
• Cardiac surgery
• Resuscitation
• Shock
• Pulmonary edema
• Oxygen transport: Ventilation and perfusion.

41. COMPLICATIONS
• Minor arrhythmias (most common)
• Pulmonary artery rupture.
• Severe arrhythmias
• Death.

43. PULSE OXIMETER

44. PULSE OXIMETERS
• The pulse oximeter provides the continuous monitoring of patients
haemoglobin saturation using a two_wavelength light absorption
technique.
• The monitor filters out of the effects of ambient light, tissues,skin
pigment,and venous blood.
• It focus on the pulsaltile absorption due to pulsaltile arterial blood.
• Pulse oximeter were developed in the 1980 and rapidly proved their
value in anesthesia.

45. • Pulse oximeter allows rapid ,beat by beat non invasive monitoring of
blood oxygenation.
• Pulse oximetry have been a major advance in improving the safety
ofanesthesia.

46. Working Principle
• The value of R is correlated to saturation percentage in a “look –
up”table.
• The look-up table was derived from the human testing.
• For example ,an R of 1 corresponds to saturation of 85 percentage in
the average patients.The accuracy is 1-2 percent.

47. • The disadvantage of using
pulsoximetry that it is motion
sensitive sensitive and that
substances are like carbon
monoxide ,methemoglobin,and
dyes that effects the readings.

48. CAPNOGRAPH

49. CAPNOGRAPHY
• The most common method of exhaled Co2 measurement is the
sidestream infrared (R) Capnography.
• Gas from the circuit is drawn intoand inhaled anesthetic agents an
infrared chamber,CO2,H2O,N2O,all absorb infrared light,but slightly
different frequencies.
• Newer monitor s have precise light sources and filters that
speciafically measures the individual gases.

50. • These monitors provide breath by breath gas analysis.
• Problems with IR capnography are that moisture can cause blockage
of gas path ,that they can’t measure oxygen or nitrogen.
• Other methods of measuring exhaled gases include RAMAN
scatterings and mass spectrometry.
• These systems measure oxygen and nitrogen directly as well as
carbon dioxide .
• They are ,however,more expensive and more complicated devices.

52. TEMPERATURE MONITORS
• Monitoring of skin temperature is nearly useless.
• Upper oesophageal and nasopharyngeal temperature are affected by
airway temperature.
• Lower oesophageal temperature is normally a good reflection of core
or blood temperature.
• Tympanic membrane temperature is also a good indication of core
temperature but it is not practical in the operating room
environment.

53. HYPOTHERMIA
Most common thermal pertubation seen in anesthesia.
• Most anaesthetics are vasodilots causing heat loss and hypothermia.
• Cool room temperature,
• Evaporation.

54. SYSTEMIC EFFECTS OF HYPOTHERMIA
• KIDNEYS:Decreased GFR,No
urine output at 20 degrees C.
• ENDOCRINE SYSTEM:
Decreased adrenaline and-
adrenaline
Hyperglycaemia.
• ACID BASE BALANCE:
Increased solubility of blood
gases.
Acidosis.
CNS: Bradycardia, Hypotension,
Ventricular arrhythmia,if
temperature is less than 28
degrees C.
BLOOD:Increased blood viscosity
and platelet count.
RESPIRATORY SYSTEM:
Respiratory arrest below
23degress C.
Oxygen dissociation curve is
shifted to left.

55. TREATMENT OF HYPOTHERMIA
• Warm intravenous fluids
• Increase the room temperature.
• Cover the patient with blanket s.
• Forced warm air by special
instrument(Bair Hugger airflow
device)

57. PERIPHERAL NERVE STIMULATION
• Peripheral nerve stimulation (PNS) monitoring is not required by the
ASA standards .
• However,it is an important safety monitor in patients who are
receiving a neuromuscular blocking drugs.
• Train of four monitoring assess the level of nondepolarizer blockade
and double burst stimulation assess return strength at the end of the
case.

58. • Clinical monitoring of neuromuscular blockade during anesthetic is
difficult without PNS monitor .
• Clinical assessment of strength is important,however at the
conclusion of an anesthetic before a final decision is to made to
extubate the patient.

62. MONITORING DEPTH OF ANESTHESIA
• Tachycardia
• Lacrimination
• Perispiration
• Hypertension
• Movement to painful stimuli
• Eye movements
• Preserved reflexes.
• EEG
• Patient evoked response
• Bispectral index
• Entrophy

63. EVOKED RESPONSES
Assessing the integrity of neuronal
tissues during surgeries.
• Somatosensory Evoked
Response(SSEP)
1. Any surgeries that can compromise
vascular supply of sensory tract.
2. Spinal surgeries ,Thoracic and
abdominal aorta,and surgery of
brain area.
• Audio evoked potential (AEP)
1. For involving auditory pathways.
2. Acoustic neuroma and posterior
fossa pathways.
• Visual evoked potential (VEP)
1. For procedures involving visual
tracts
2. Optic glioma
3. Pituatary tumours.

64. ELECTROENCEPHALOGRAM(EEG)
• EEG can assess cerebral ischaemia during neurovascular surgeries –
carotid endarterectomy.
Modalities of EEG:
1. All inhalational and intravenous anesthetics agents produce
biphasic pattern of EEG.
2.Lower dose-causing excitation.
3.High dose-causing depression.

65. Analysis of blood loss:
1. Estimation of blood loss is
done by weighing blood
soaked
swabs,sponges(Gravimetric
method)
2. Estimation of blood loss in
suction bottle(Volumetric
method)
3. The accurate method is
colorimetric method.
• Expired Gas Analysis:
There is multigas analyse which
measures the concentration of
anesthetic analysers like nitrous
oxide, inhalation agents like
halothane,and insoflurane etc.
These are mass spectrometers
and Raman gas analysers.