Principles of emergency anesthesia

Dr Masood Entezari
In elective surgery:
- madding correct diagnosis
- identifying and treating medical disorders
- occurring an appropriate period of starvation
 One or more of these conditions are often not met in
emergency work
Further problems :
- dehydration
- electrolyte abnormalities
- hemorrhage
- pain
 The components of general anesthesia are the same in
elective and emergency surgery
Components of general anesthesia
• preoperative
• Premedication
• Induction
• Maintenance
• Reversal
• Postoperative care
The key to success in emergency anesthesia is a
thorough preoperative assessment
 Particular attention must be given to:
- the search for medical problem
- the occurrence of hypovolemia
- an evaluation of the airway
 There are very few patients whose clinical state is so
life – threatening that they need immediate surgery
( true emergency)
Emergency immediate operation within one hour of
surgical consultation and considered
life – saving , for example, ruptured aortic
aneurysm repair
Operation as soon as possible after
resuscitation , usually within 24 hour of
surgical consultation , for example , intestinal
Early operation between 1 and 3 weeks ,
which is not immediately life – saving , for
example, cancer surgery, cardiac surgery
Operation at the time to suit both the patient
and surgeon
The vast majority of patients benefit from :
- the correction of hypovolemia
- the correction of electrolyte abnormality
- stabilization of medical problem
- waiting for the stomach to empty
 When to operate is the most important decision that
has to be made in emergency work
 Emergency anesthesia ≈ general anesthesia
 But
Classification of anesthetic techniques
• general anesthesia
- intubation of unprotected airway
- spontaneous respiration or controlled ventilation
- use of muscle relaxants
• regional anesthesia
• combination of general and regional anesthesia
• sedation
- intravenous
- inhalational
• combination of sedation and regional anesthesia
Due to the increasing use of regional anesthesia ,
hypovolemia must be corrected pre- operatively
 The sedated patient can talk to the anesthetist at
all time
 If not ,then airway control may be lost with the
risk of aspiration of gastric contents
Starvation for at least 4-6 hours in emergency
 All emergency patients should be treated as
having a full stomach and so at risk of vomiting ,
regurgitation and aspiration
 Occurring the vomiting at the induction and
emergence from anesthesia
 Entering gastric acid to the lungs and creating a
pneumonitis can be fetal
Silent regurgitation : passive regurgitation of
gastric content up to esophagus
 Regurgitation is particularly likely at induction
of anesthesia when several drugs used
 Regardless of the period of starvation ,in
emergency anesthesia there is always a risk of
The trachea must be intubated as rapidly as
possible after induction
 Endoteracheal intubation is performed under
general anesthesia when there is no problem in
preoperative assessment of the airway
Some basic requirements for endoteracheal intubation:
- skilled assistance must be present
- the trolley must tip
- the suction apparatus must work correctly
be left on
- a rang of sizes of endoteracheal tubes must
- spare laryngoscopes must be available
- ancillary intubation aids, gum elastic bougie
and stillettes must be available
Management of endotracheal intubation when
risk of aspiration
•Empty stomach
- from above by nasogastric tube
- from below by drugs ,for example, metoclopramid
•Neutralise remaining stomach contents
- antacids
- use of H₂ blocking drugs to prevent
acid secretion
• Stop central nervous system induced vomiting
- avoid opiates
- use of phenothiasines
• Correct anesthetic technique
- rapid sequence induction
- preoxygenation , cricoid pressure , intubation
Neither physical nor pharmacological methods should
be relied on to empty the stomach completely
 In some specialties (obstetrics) an H₂ receptor blocking
drug and 30 ml sodium citrate used orally 15 minutes
before induction of anesthesia
 Opiates delay gastric emptying and increase the
likelihood of vomiting
• The only reliable way
to prevent
using the correct anesthetic technique
(rapid sequence induction)
Breathing 100% oxygen for at least 3 minutes before
 In breathing oxygen only, the lungs denitrogenate rapidly
and after 3 minutes contains only oxygen and carbon
 There is a greater reservoir of oxygen in the lunges to
utilize before hypoxia occurs
Identifying the cricoid cartilage on the patient
before induction of anesthesia
 Warning the patient that they might feel
pressure on the neck as they go to sleep
 Pressing down on the cartilage continuously until
telling the anesthetist to the assistant for
Object: compressing the esophagus between
the cricoid cartilage and vertebral column
 Pressure is usually undertaken by firm but gentle
pressure on the cartilage by the thumb and forefinger
of the assistant
 The cricoid is easily identifiable , forms a complete
tracheal ring , and the trachea is not distorted when it
is compressed
 Giving a neuromuscular blocking drug to facilitate
The neuromuscular drug must act rapidly and have a
short duration of action
 The lungs are not ventilated during a rapid sequence
induction ; this will prevent accidental inflation of the
stomach , which will further predispose the patient to
regurgitation and vomiting
 An agent with a short duration of action is valuable
because in cases of failed intubation spontaneous
respiration will return promptly
Suxamethonium has many side effects but remain the
best drug available
Major side effects of suxamethonum
• Muscle aches
• Bradycardia
• Raised intracranial pressure
• Raised intraocular pressure
• Raised intragastric pressure
• Allergic reactions
• Hyperkalemia in burns , paraplegia, some myopathies
• Prolonged action in pseudo cholinesterase deficiency
• Malignant hyperthermia
Releasing the cricoid pressure only when :
- the trachea is intonated
- the cuff inflated
- the correct position of the tube is
 The anesthetic is maintained with :
- a volatile agent
- nitrous oxide
- oxygen
- competitive relaxant
- suitable analgesia
The reversal of the relaxant at the end of the procedure is
undertaken with the anticolinesteras (neostigmine)
 Atropine or glycopyrrolat is given concomitantly to stop
bradycardia occurring from the neostigmine
 Major disadvantage of potential hemodynamic instability
of rapid sequence induction: hypertension and tachycardia
following laryngoscopy and intubation
 This is more severe in urgent surgery than elective surgery
because of using opiates at intubation of anesthesia
Every anesthetic ,not just emergency work , should be
considered from the point of view of unexpected
vomiting or regurgitation
 Some cases are at high risk and rapid sequence
intubation should be considered carefully as an option
in this group
High risk factors for regurgitation
• Oesophageal disease
- pouch
- stricture
• Gastro-oesophageal sphincter abnormalities
- hiatus hernia
- obesity
- drugs
• Gastric emptying delay
- trauma
- pyloric stenosis
- gastric malignancy
- opiates
- patient predisposition , anxiety
- pregnancy
- recent food intake
• Abnormal bowel peristalsis
- peritonitis
- ileus – metabolic or drugs
- bowel obstruction
Pulmonary aspiration may be obvious
 Silent pulmonary aspiration is presenting as a
postoperating pulmonary complication
 Treatment :
» suction of airway
» oxygenation of the patient(priority)
» broncoscopy (may be required)
Signs of pulmonary aspiration
• None
• Oxygen destruction
• Coughing
• Tachypnea
• Unexplained tachycardia
• Wheeze
• Hypotension
• Pneomonitis
• Postoperative pulmonary disease
If the patient is not paralyzed , surgery permitting, he
or she should be allowed to wake up
 If paralyzed , intubation and ventilation must occur
and oxygenation maintained
 Bronchospasm may be treated with aminophylline
 Further treatment may include antibiotics , other
bronchodilators and steroids
 Aggressive early management is required
Anesthesia for emergency surgery needs careful
preoperative assessment and adequate resuscitation
must be undertaken before surgery
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