Risk in Anesthesia Flashcards
Factors to consider about the choice of technique
Coexisting diseases
Risk of aspiration
Age, cooperation of the pt.
Coagstatus
Previous anesthetic/surgical experiences
Patient desires/beliefs
ASA 1
A fit and healthy patient
ASA 2
A patient with a mild systemic illness
Ex. Controlled hypertension diabetes
ASA 3
A patient with severe but non-incapacitating illness
e.g. uncontrolled HTN, DM with vascular issues, previous MI, COPD
ASA 4
A patient with severe incapacitating life-threatening illness
E.g. CHF, renal or hepatic failure, unstable angina
ASA 5
A moribund pt who is expecting to die without surgery within 24 hours
Ruptured AAA, PTE, increased ICP
ASA 6
Brain Dead
Adding E to a ASA clasification
Means Emergency
Group A
ASA 1 or 2 with a low risk procedure
Group B
ASA 1 or 2 with a high risk procedure
Group C
ASA 3 or 4 with a low risk procedure
Group D
ASA 3 or 4 with a high risk procedure
Cardiac risk in non cardiac surgeries
Aortic, major vessel, (even some peripheral vessels) surgeries carry a high risk of cardiac related events.
Intraperitoneal, intrathoracic, carotid, head/neck, ortho, even prostate related surgeries have considerable risk but less than the above.
Lower risk for cardiac events: Endoscopic, cataract, breast, superficial etc.
Disclosure
Modern medicine and law requires patients/families have all the relevant information with which to make informed decisions.
Only after patients/family are fully informed of the risks can they be said to have made an informed consent to continue.
Disclosure for General Anesthesia
What are the Frequent Complications
These may be frequent but tend to have minimal impact
Oral/dental damage
Sore throat/hoarseness post-op
N/V, drowsiness/confusion, urinary retention
Disclosure for General Anesthesia
What are the Infrequent Complications
These are infrequent and are more severe
Awareness during surgery
Temp visual loss
Aspiration, drug reactions
Malignant Hyperthermia
Coma
Death
How Safe is Anesthesia
For healthy patient, a planned operation is as dangerous as pregnancy
General anesthesia is generally very safe but there are risk factors
There are very few conditions where anesthesia is likely to be lethal
Anesthesia is very safe and far less dangerous than the effect of surgery
Consciousness During Anesthesia
A person who says they are conscious during an operation is not hysterical or insane
These stories should always be taken seriously
Hypoxia and Mental Function
Extreme Hypoxia
SaO2 <40 causes failure of all brain and brainstem functions, causing loss of consciousness, abnormal, or actual cessation of breathing, and ultimately death.
Hypoxia and Mental Function
Severe Hypoxia
SaO2 40-60
Induces all the effects of moderate hypoxia, except that the degree of brain malfunction is more extreme.
Supplementary and primary motor cortex malfunction so people do not even think of moving, and when a few people do try to move, they discover they are totally paralyzed.
And because severely oxygen starved people do not move, they appear unconscious even though they are often still conscious.
Hypoxia and Mental Function
Moderate Hypoxia
SaO2 60-80
Affect the brain and senses
Removes pain and discomfort making people calm
Supplementary motor cortex malfunction results in a lack of desire to move,
Primary motor cortex malfunction causing muscle weakness for when they do move
More severe degrees of moderate hypoxia may also induce life-review, or out-of-body experiences.
Hypoxia and Mental Function
Mild Hypoxia
SpO2 > 80%
Will not affect the functioning of the brain
Perioperative lung function
The lungs must get sufficient oxygen into the body to oxygenate the blood.
The lungs must eliminate carbon dioxide from the body to prevent carbon dioxide accumulation.
The patient must be able to generate a productive cough, otherwise mucus accumulation will occur resulting in atelectasis and/or lung infection or pneumonia.
The patient must be able to significantly increase their respiratory minute volume to compensate for factors such as increased postoperative metabolic rate, elevated body temperature, possible infections, pneumonia, etc.
Inabilityto significantly raise and sustain an elevated respiratory minute volume results in exhaustion and respiratory failure.
