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 !!!

• Ulnar neuropathy • Awareness • Neurological injury after spinal • After blocks

• Not going into the detail

What is it ?? Risk • Specific population →• Specific hazard →• Specific conditions. →• Specific outcome →

Hazard and risk !!

• 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

75%

5%

20%

Previously it was like this

But now

Four broad sources of risk .

• 1. Technical • 2. Anaesthetic • 3.Medical illness • 4. Surgical

Possible ways

• 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

Summary • Definition • Specific • a/a+b • 5, 20 , 75 % , -- Goals • New settings • ASA • Hopkins • Edward • ABCD • Information systems

Thank you all