emergency anaesthesia 2

8/3/2019 Emergency Anaesthesia 2

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Emergency Anaesthesia

Prepared byDr. Mahmudul Hasan

Assistant Professor

Dept. of Anaesthesia,Ragib-rabeya Medical College, Sylhet.


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Introduction

Pt. scheduled for elective surgery are usually-1. Optimal physical and mental condition

2. Definitive surgical diagnosis

3. Well controlled coexisting medical diseases

In contrast,

Pt. with a surgical emergency may have-

1. Uncertain diagnosis

2. Uncontrolled coexisting diseases

3. Cardiovascular, resp. And metabolic derangements


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Introduction(contd)

Thus in practice of emergency anaesthesia to beprepared for all potential complicationsincluding-

vomiting

Regurgitation

hypovolumia

Haemorrage

Abnormal reaction of drugs

Electrolyte disturbance

Renal impairment etc.


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Pre operative assesment

The objective of emergency anaesthesia:1. Correction of the surgical pathology

2. Minimum risk to the patient

These require adequate and accurate pre operative evaluation ofpatients general conditions with attention of specific problems thatmay influence anaesthetic management.

Pre operative preparation and method of anaesthesiawill depend on-

1. Surgical diagnosis

2. Magnitude of proposed surgery

3. How urgently surgery is required


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Pre operative assesment (contd)

A pertinent medical and drugs history is important.In particular enquiry is made into the presence andseverity of specific symptoms relevant tocardiovascular reserve:

AnginaProductive cough

Dyspnoea on effort

Orthopnoea

Nocturnal caughing bouts

Such symptoms should provoke details enquiry into

CVS and respiratory systems.


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Pre operative assessment (contd)

Physical examination:

To identify cardiopulmonary dysfunction which

increases significant risk of anaesthesia

including-

Basal crepitation

Raised JVP

Arrhythmia

Abnormal heart sound


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Pre operative assesment (contd)

Airway evaluation is important if rapid

sequence of induction is contemplated-

Irregular dentition

Limitation of mouth opening

Poor range of movement at the atlanto-

occipital joint. Reduced distance between the hyoid bone

and mental symphysis

-associated with difficult laryngeoscopy.


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Pre operative assesment(contd)

Review of lab investigations and urgent

requests are made for additional test may help

in management of patient


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Assessment of volaemic status

Assessment of intravascular volume is essential,

as underestimated hypovolaemia may lead to

circulatory collapse during induction of

anaesthesia.

Intravascular volume deficit:

- Assessment of blood loss may be made from

history and clinical evaluation.

Cli i l i di f f bl d l


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Clinical indices of extent of blood loss:

Class of

hypovolaemia

1

Minimal

2

Mild

3

Moderate

4

Severe

% of blood lost 10 20 30 Over 40

Vol. lost in (mL) 500 1000 1500 2000+

Heart rate

(beat/min)

Normal 100-120 120-140 Over 140

Arterial

pressure (mm

Hg)

Normal Orthostatic

hypotension

Systolic below

100

Systolic below

80

Urinary

output(mL/hr)

Normal

(1

mL/kg/hr)

20-30 10-20 Nil

sensorium Normal Normal Restless Impaired

consciousness

State of

peripheralcirculation

Normal Cool and pale Cold and pale,

slow capillaryrefill

Cold and

clammyperipheral


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Extacellular fluid deficit:

Assessment of extracellular fluid deficit isdifficult as considerable losses occur before

clinical signs are apparent.

Guidance is obtained from

Nature of surgical condition

Duration of impaired fluid intake

Symptoms associated with volume loss(vomiting)


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Extracellular fluid deficit (contd)

Extracellular fluid loss may be graded into 4

degree of severity. The loss is expressed as

percentage of body weight loss as fluid.


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Indices of extent of loss of extracellular fluid:

% body weight lost as

water

mL of fluid lost per

70 kg

Signs and symptoms

Over 4% (mild) Over 2500 Thirst, reduced skin elasticity,

decreased intraocular pressure, dry

tongue, reduced swOver 4% (mild)

Over 6% (mild) Over 4200 As above, plus orthostatic pypotension,reduced feeling of peripheral veins,

oliguria, low CVP, apathy,

haemoconcentration

Over 8% (moderate) Over 5600 As above, plus hypotension, thready

pulse with cool peripheries

Over 10-15% (severe) Over 7000-10500 Coma, shock followed by death


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The full stomach

Vomiting and regurgitation of gastric contentsfollowed by aspiration into trachubronchial tree

is a potential problem during induction of

emergency anaesthesia.

Most important factors determining the extent of

gastric regurgitation-1. Lower oesophagel sphincter

2. Rate of gastric emptying.


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Lower oesophagel sphincter

It is an area (2-5 cm) with high resting intra-

luminal pressure in the region of cardia. This

sphincter relax during oesophageal peristalsis to

allow food into stomach but remain contracted

other time. It can not define anatomically but may

be detected using intraluminal pressure

manometry.

LOS is main barrier preventing reflex of gastric

contents .


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Lower oesophagel sphincter (contd)

Drugs that decrease LOS pressure and increase

tendency to gastro oesophageal reflex-

1. Anticholinergic drugs

2. Ethanol

3. Ganglion blocker4. Tricyclic anti depressent

5. Opioids

6. TPS


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LOS(contd)

Factors which delayed gastric emptying

1. Shock2. Pain, fear , anxiety

3. Late pregnency

4. Deep sedation

5. Solid foods


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Situation in which vomiting and regurgitation may occur

Full stomach:With absence or abnormal peristalsis-

Peritonitis of any cause

Post operative ileus

Metabolic ileus

-Hypokalimia

-Uraemia

- Diabetic ketoacidosis Drug induced ileus

-Anticholenargic

With obstruction of peristalsis-

Gastric carcinoma

Pyloric stenosisWith delayed gastric emptying-

Shock

Fear, pain, anxiety

Late pregnency

Deep sedation Recent solid and fluid intake

Other cause:

Hiatus hernia

Oesophageal

stricture(benign or

maliglant) Pharyngeal pouch


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Techniques of anaesthesia

It is important to recognize the pt. who may have

significant gastric residue and who is in danger

of aspiration. The anaesthetic management of

such pt. may be described in 5 phases-

1. Preparation

2. Induction

3. Maintanance

4. Reversal and emergence

5. Post operative management


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Techniques of anaesthesia(contd)

Phase-I

Preparation:

a) Insertion of N-G tubeb) Clear oral antacides(Na-citrate) to raise the pH

of gastric contents

c) Pre operative administration of H2 receptorantagonist


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Techniques of anaesthesia

Phase-II

Induction:

Rapid sequence induction:Indications:

1. Full stomach

2. Pregnant pt.

3. Bowel obstruction

4. Morbid obesity

Techniques of Rapid sequence induction


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Techniques of Rapid sequence induction:

1. Pre oxygenation with 100% o2 for 3-5 min.

2. Pt. to be sniffing position(nack flexed on shoulder and head

extend).

3. Skilled assistant on right side to perform cricoid

pressure(sellicks manoeuvre)

4. Sleeping dose of induction agent given

5. Cricoid pressure should be given as soon as consciousness is

lost. (some prefer to inform pt. and apply it just before induction

and maintained untill the cuff of ETT is inflated- cricoid pressure

1-3 kg wt or 40N)

6. Without waiting to the effect of induction agent paralysis dose of

succinylcholine is administrated immediately

7. As soon as the jaw being to relax, laryngoscopy is performed and

trachea is intubated, cuff is inflated and cricoid pressure is

removed.

Ph III


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Phase-III

Maintanance of anaesthesia:

1. N2O 50-66% with O2 depending on patients

condition;

2. Volatile anaesthetic agent with appropriateconcentration.

3. NMBA: Rocuronium and atracuronium is drugs

for routine use.

Pancuronium is usefull in pt. with hypovolumia

as it increases arterial pressure.


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Phase-IV

Reversal and emergence:

After insertion of last skin suture-

1. Discontinuation of anaesthetic drugs2. Ventilation manually

3. Neostigmine and atropine are given in one bolus.

4. Extubation of trachea done after protectiveairway reflex become because chance of

aspiration is great.

5. Level of consciousness should be assessed.


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Phase- V

Post operative management:

1. Proper analgesia (eg. Morphine 0.2 mg/kg)

2. Fluid balance : maintanance and abnormal loss.3. Monitoring of vital signs


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The anaesthesist and major trauma:

Management of a pt. with major trauma

requires a multidisciplinary team effort. In

many hospitals the anaesthesist/ICUtrainee is a integral member of trauma

team. Trauma management is based on

Advanced trauma life support (ATLS)protocols.


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The anaesthesist and major trauma(contd)

The suggested scheme for trauma management is as follows:1. Rapid primary survey: Recognition and treatment of any

immediate life threatening complications like-

Airway obstruction

Tension/ open pneumothorax Massive haemothorax

Fail chest

Cardiac temponade

2. Resuscitation of vital functions:

Control of maemorrage

Intravenous accesss

Volume resuscitation


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The anaesathesist and major trauma(contnd)

Suggested scheme for trauma management

3. Detailed secondary survey-

Recognition of any potentially life threatening injury.

Example- Ruptured aorta

pulmonary/ cardiac construction

Diaphragmatic rupture

Haemoretroperitoneum

4. Definite care

Steps 1 and 2 are performed simultaneously.


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The anaesthesist and major trauma(contd)

Airway/ breathing:

Airway assessment reveals one of the three clinical scenarios-

1. pt. is conscious, alert, talking

High flow of o2 via face mask

No need for immediate airway intervention

A full clinical evaluation can be done

2. pt. has a reduced conscious level but some degree of airway control gagreflex still present.

If pt. is maintaining airway and breathing adequately then no need for

immediate intervention. Further evaluation can be done

3. pt. has reduced conscious level. Gag reflex absent.

Tracheal intubation and artificial ventilation should be carried out atonce.

l


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Circulation:

Haemorrhage is the most common cause of shockin the injured pt.

Pt. with major trauma often require urgentrestoration of circulatory blood volume. Isotonicelectrolyte are used for initial resuscitation and1-2 litre Hartmann.s solution is given rapidly andpt. response is assessed.

Whole blood is ideal fluid for restoration of bloodvolume in the haemorrhage shock. If crossmatched blood is not yet available a syntheticcolloid solution may be given.


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DefinitivecareOn arrival in the theatre, the pt. is placed on operation table.

100% O2 is given. Anaesthesia should be induced so thatsurgery can start as soon as possible.

Induction:

Rapid sequence induction using Ketamin (0.3-0.7 mg/kg)

Ketamin should not be used in pt. with significant head

injury.

Etomidate 0.1-0.3 mg/kg is an alternative for Normovolumic

pt.

Pancuronium and Rocuronium is given in small incremental

dose to maintain relaxation.

In shock state MAC value is approached more rapidly so

volatile agent should be reduced.


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Thank you

emergency anaesthesia 2

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