2. ANAESTHESIA
Anaesthesia ( from Greek an “ WITHOUT “ asthesis “ SENSATION “ )
Anaesthesia state includes:
>Reversible Loss Of Consciousness
>Loss of Memory ( AMNESIA )
>Lack of pain ( Analgesia )
>Immobility ( Skeletal Muscle relaxation ) and loss of sensation to any noxious
stimuli .
Three Periods of Anaesthesia :-
1. Preoperative Period
2. Perioperative Period
3. Postoperative Period
3. Discussion On Following :-
Evolution of Preoperative evaluation
Goals And Benefits Of Preoperative Evaluation
Scope Of Preoperative Evaluation
Components Of Airway Examination
Preoperative Evaluation In Specific Conditions And Diseases
Preoperative Risk Assessment
Planning For Anaesthesia
Benefits Of Preoperative Evaluation
4. Preoperative Evaluation :
Definition :- The process of clinical assessment that precedes the delivery of
anaesthesia for surgery and for non-surgical procedures
It consists of the consideration of information of multiple sources , which
includes:-
> Patient’s interview
> Medical Records
> Physical Examination
> Airway Assessment
> Finding from Medical tests and evaluations
5. Goals Of Preoperative Evaluation
Allay Anxiety
Information regarding pertinent medical history
Doctor Patient Relationship
Formulate assessment of patient’s perioperative risk and develop a plan for
any clinical optimisation
Focussed clinical examination
Documentation of comorbid illness
Selective referral to specialist
Ordering Preoperative investigations as needed
Discussing Perioperative and Postoperative care with surgical team
Delay and cancelling the surgical procedure if deemed appropriately
Patient consent
6.
7. Components Of Preoperative Evaluation
Medical History
Physical Examination
Assessment of functional status
It is observed that 56% Diagnosis is made on the basis of Medical History and
when done with Physical Examination then 73% of the diagnosis is made.
Inadequate preoperative evaluation leads to 3% perioperative adverse
outcome .
8. Medical History
Demographic Details
Presenting Complaints
H/O Presenting Illness
Past Medical History
Allergy History
Any Surgical History
Previous Anaesthetic History – any h/o Difficult intubation , any h/o allergy at
that time .
Drug History
Family History
Social History
9. Physical Examination
General Examination:-
Vitals-
> Blood pressure measurement
> Pulse rate
>Respiration rate
> Temperature
=> Jaundice , Pallor , Cyanosis , Clubbing and Edema
=> Hydration Status
=> Weight ( Kg )
=> Height (cm)
10. .
Systemic Examination :-
> Cardiovascular examination
> Pulmonary Examination
> Central Nervous Examination
> Hepatic System Examination
> Renal System examination
Special Examination :-
>Airway Assessment
>Peripheral Venous Access
> Spinal Examination
11. Cardiovascular Examination
Pulse :- Rate, rhythm, character and volume.
BP
JVP:- Height and character
Ankle edema:- Present or absent
Inspection :- any scar , abnormal vessels, lumps, chest shape, apex beat position
Palpation :- confirm apex beat, character, presence of thrills and peripheral
pulses on both sides
Percussion :- Precordium- size of heart
Auscultation :- heart sounds, murmur
13. Assessment Of Functional Status
The assessment of the patient’s cardiopulmonary fitness or functional
capacity is an integral component of the preoperative clinical examination.
This information is typically used to estimate a patient’s risk for major
postoperative morbidity or mortality
There is a reasonable body of evidence demonstrating an association between
poor preoperative functional capacity and increased perioperative risk .
Functional Capacity is typically quantified in using the Metabolic Equivalent of
Task (METS)
One MET is approximately the rate of energy consumption at rest ( 3.5
ml/kg/min )
14.
15. METS
Significance
If METS > 4 , the perioperative risks are minimal
If METS < 4 , the perioperative risks are maximum and needs further
evaluation
16. .
DASI scores have been shown to improve prediction of postoperative cardiac
complications following non-cardiac surgery
Formula for conversion of DASI to METS:-
Estimated METS =[( 0.43 X DASI score ) + 9.6 ] / 3.5
Other alternatives for estimating functional capacity include simple exercise
tests ( eg – 6 minute walk test, incremental shuttle walk test ) , ECG exercise
test , or CPET .
17. AIRWAY
Definition – Airway is the passage through which the air/ gas passes during
respiration.
Incidence of Difficult Intubation reported to range between 0.13-5.9%.
Difficult Intubation can be predicted and expert Anaesthesiologist is called for
the case.
Evaluation is the first step in management of difficult intubation .
18. AIRWAY CLASSIFICATION SYSTEM
MALLAMPATI SCORE Laryngoscopic view
CORMACK LEHANE
GRADE GRADE
1 Full view of soft palate,fauces,
uvula, tonsillar pillars.
2 Soft palate , fauces , upper
portion of uvula
3 Soft palate , uvula base
4 Hard Palate Only
1 Entire Glottic
2 Posterior Commissure
3 Tip Of Epiglottis
4 No Glottic Structure
19.
20.
21. AIRWAY EVALUATION
Mentothyroid distance -> Normal >6.5 cm
Mentosternal distance -> Normal >12.5 cm
Mentohyoid distance -> Normal >6 cm
Neck Movement -> Flexion And Extension of Neck, History Of Radiation
Nasal Cavity
22. Difficult Intubation
Mouth opening -> Less than 3 cm
Head Extension -> Less than 80 degrees
Neck Flexion -> Less than 25 degrees
Head / Neck Rotation -> Less than 70 degrees
Micrognathia
Macroglossia
Protrusion of teeth
Short Neck / Thick Neck
Morbid Obesity
23. Airway Examination
Normal :-
Examination has to done in sitting position.
-> Opens Mouth Normally ( Adults : greater than 2 fingers widths OR 3 cm )
-> Able to visualize at least part of the Uvula and tonsillar pillars with mouth
wide open and tongue out ( patient sitting )
-> Normal Neck Flexion and Extension without pain / paresthesias
24. .
Abnormal
-> Small or recessed chin
-> Inability to open mouth normally ( < 3cm )
-> Inability to visualize at least part of Uvula or Tonsils with mouth open and
tongue out.
-> High Arched Palate/ Narrow Palate
-> Tonsillar Hypertrophy
-> Limited range of Neck movement
-> Low set ears
-> Significant obesity of the face/neck
25. Airway assessment : Predictive tests
sensitivity = 50-60%
Mallampati modified test :
Visibility of pharyngeal structure
Patil test:
Thyromental distance < 6cm
Mandibular protrusion:
Class C – Inability to protrude lower incisors beyond the upper
incisors
Wilson Test
Radiological assessment of the mandible and cervical spine
26.
27. ASA ( American Society of Anaesthesiologist )
physical classification system
GRADE MEDICAL STATUS MORTALITY
ASA I Normal healthy patient without organic,
biochemical or psychiatric disease
0.06-0.08
ASA II Mild Systemic disease with no significant impact
on daily activity eg- controlled DM/HTN,
obesity( 30<BMI<40)
Unlikely to
have impact
0.27-0.4
ASA III Severe Systemic disease that limits activity eg-
poorly controlled DM/HTN, BMI>=40, H/O (>3
months ) of MI,CVA,TIA,or CAD/stents
Probable
impact
1.8-4.3
ASA IV An incapacitating disease that is a constant
threat to life eg-(<3months) MI,CVA,TIA,or
CAD/stents,Sev LV dyfn, ARDS, ESRD
Major impact
7.8-23
ASA V Moribund patient not expected to survive 24 hrs
eg:-ruptured aneurysm, massive trauma ,ICH
9.4-51
ASA VI Brain dead patient whose organs are being
removed for donor purposes
E EMERGENCY OPERATION
28. Preoperative Evaluation of Patient with
Co-existing diseases
Cardiovascular disorders:-
-> Ischaemic Heart Disease
-> Hypertension
-> Heart Failure
-> Conduction Defect and Arrhythmia
-> Peripheral Vascular Disease
Patient with history of MI are at greater risk of perioperative reinfarction.
The presence of unstable angina has been associated with high perioperative risk
of MI.
The presence of active congestive heart failure has been associated with an
increased incidence of perioperative cardiac morbidity.
29. RISK CALCULATOR
Quantifies the cardiac risks during perioperative period.
REVISED CARDIAC RISK INDEX (undergoing elective major non cardiac
procedures)
1) High Risk Type Of Surgery
2) H/O Ischaemic heart Diseases
3) H/O Congestive Heart Failure
4) H/O Cerebrovascular Disease
5) Preoperative Treatment with INSULIN
6) Preoperative Serum Creatinine > 2mg/dl
30. PULMONARY DISORDERS
Pulmonary diseases which are concerned to the anaesthesiologists are as follows:-
1. OSTRUCTIVE LUNG DISEASES
I. ASTHMA
II. COPD
III. BRONCHIECTASIS
IV. CHRONIC BRONCHITIS
V. EMHYSEMA
2. RESTRICTIVE LUNG DISEASES
I. INTERSTITIAL LUNG DISEASES
II. IDIOPATHIC PULMONARY FIBROSIS
III. SCOLIOSIS
IV. NEUROMUSCULAR DISEASE ( AMYOTROPIC LATERAL SCLEROSIS or MUSCULAR
DYSTROPHY
31. Preoperative Investigation
General
1. Complete Blood Count
2. Electrolytes
3. Blood Urea Nitrogen ( BUN ) , Serum Creatinine
4. Blood Sugar Level
5. Liver Function Test
6. ECG
7. ECHO
32.
33. Preparation For Anaesthesia
Continuing Current medications
It is the responsibility of the anaesthesiologist to instruct patients regarding
which medications to take and which to hold preoperatively.
34. Benefits Of Preoperative Evaluation
Decreased Cost of treatment
Decreased Hospital stay
Decrease Morbidity and Mortality
Unnecessary cancellation and postponement of Surgical procedures
35. Take Home Message
A Mnemonic has been suggested for pre-anaesthetic assessment , to ensure that
all aspects are covered.
A-Affirmative history, Airway
B-Blood Hemoglobin,blood loss estimation,and blood availability, Breathing
C-Clinical Examination , Co-morbidities
D-Drugs being used by the patient, Details of previous Anaesthesia and Surgeries
E-Evaluate investigations, End point to take up the case for surgery
F-Fluid status , Fasting
G-Give physical status , Get consent