Anaesthesia risk
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu),
Dip. Diab. DCA, Dip. Software statistics
PhD (physio)
Mahatma Gandhi medical college and
research institute – Puducherry – India
Define risk
• Risk is defined as the probability of an
outcome within a population
• Example
• aspiration pneumonitis in GA of LSCS
Does anaesthesia really do this ??
• “It is a fact that to anesthetize a human being,
to deprive him of consciousness outright, is to
take a considerable step along the road to
killing him.”
• —W.G. Hawkins, 1957
Mortality
• This is not only termed as risk
Incidence !!!
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Ulnar neuropathy
Awareness
Neurological injury after spinal
After blocks
• Not going into the detail
What is it ?? Risk
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Specific population →
Specific hazard
→
Specific conditions. →
Specific outcome →
Hazard and risk !!
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LSCS ,
loss of airway reflexes
aspiration
Pneumonia
In simple terms
• Risk = Incidence Rate =
• Persons with Outcome
Population Exposed to Hazard
a/a+b
Practical terms
• Any morbidity or mortality within 30 days of
surgery and anaesthesia
• Can be taken as related to surgery and
anaesthesia
• 1 in 2 lakh (mortality ), 1 in 25000(morbidity)
Goals
• 1. to assess the potential risk in performing
the desired procedure on a specific patient
• Emergent – ectopic , head injury
• Cholecystectomy
• Mammoplasty
• 2. identify modifiable risk factors
Various factors and their percentage
5%
75%
20%
Previously it was like this
But now
Four broad sources of risk .
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1. Technical
2. Anaesthetic
3.Medical illness
4. Surgical
Possible ways
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inquests, case reports, case series,
study commissions,
registries, cohort studies,
Clinical trials, clinical practice guidelines
establishment of the multidisciplinary
Anesthesia Patient Safety Foundation
(emulated in Australia and elsewhere
Confidential
• The Secretary of State is satisfied that the
disclosure of documents about individual
cases prepared for the Enquiry into
Perioperative Deaths would be against the
public interest and would undermine the
whole basis of a confidential study.
• The data or information sent to the
Confidential Enquiry into Perioperative Deaths
is therefore protected from subpoena …
ASA
• 1941
• Found risk factors ??
ASA
• 1.Healthy patient without medical problems
• 2 Mild, well-controlled systemic disease
• 3 Severe systemic disease (not incapacitating)
4 Severe systemic disease (constant threat to
life)
• 5 Moribund (not expected to live 24 hours
regardless of operation)
• 6 Organ donor
John Hopkins risk classification
• Category 1 Minimally invasive procedure; little or
no blood loss. - office setting. Minimal risk
• Category 2 Minimal to moderately invasive
procedure. Blood loss <500 mL. Mild risk
• Category 3 Moderately to significantly invasive
procedure. Blood loss potential 500–1,500 mL.
Moderate risk
• Category 4 Highly invasive procedure. Blood loss
>1,500 mL. Major risk
• Category 5 Highly invasive procedure. Blood loss
>1,500 mL. Critical risk. Usual postoperative
intensive care unit stay with invasive monitoring
On the whole risk
Edwards Classification of the Relationship of
Anesthesia to Operative Morbidity and Mortality
• Category Definition I When it is reasonably certain
that the event or death was caused by the anesthetic
agent or technique of administration or in other ways
coming directly within the anesthetist's province
• II Similar to type I cases, but ones in which there is
some element of doubt about whether the agent or
technique was entirely responsible for the result
• III Cases in which the patient's adverse event or
death was caused by the anesthetic and the surgical
technique
• IV Events entirely referable to surgical technique
Some facts
• Studies
of
anesthesia-related
risk
have
found
that
postanesthesia respiratory depression is the major cause of
death and coma totally attributable to anesthesia.
• anesthesia-related cardiac arrest has found it to be attributable
to medication administration, airway management, and
technical problems of central venous access.
• Maternal -- increased use of regional anesthesia has led to
improvements in outcome.
• Risks related to anaesthesia only are
diminishing
• Nomorbid anaesthesia
Risk in relation to paediatric
anaesthesia
• Mortality decreased
• Critical incidents in infants younger than 1 year
were four times as common as in older children
(8.6% vs. 2.1%) and occurred mainly during the
maintenance phase of anesthesia (80.6%).
• Children with a URI are two to seven times more
likely to experience respiratory-related adverse
events
• The key factors in the prevention of patient
injury are vigilance, up-to-date knowledge,
and adequate monitoring
• Use of Anesthesia Information Management
Systems
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Summary
Definition
Specific
a/a+b
5, 20 , 75 % , -- Goals
New settings
ASA
Hopkins
Edward
ABCD
Information systems
Thank you all