This document discusses guidelines for preoperative fasting in patients undergoing procedures requiring anesthesia. It outlines recommendations for fasting times for various foods and liquids in adults, children, and special populations. The primary goal of preoperative fasting is to reduce the risk of pulmonary aspiration by allowing time for gastric emptying. However, prolonged fasting can increase risks of dehydration, hypoglycemia, and patient dissatisfaction. The document reviews techniques to decrease gastric volume and increase gastric pH as additional measures to prevent aspiration during induction of anesthesia.

1. PRESENTED BY- Dr RICHIE SANAM
1ST YEAR POST GRADUATE
MODERATOR- Dr SUBRAHMANIAM MD PROF
DEPT OF ANAESTHESIA AND CRITICAL CARE
MEDICINE

2.  History
 Introduction
 Primary goal
 Pre-operative fasting guidelines in adults
and children
 Fasting in special cases
-children
-diabetes
-trauma
-obstetrics

3. JOSEPH LISTER In the
year 1882
“While it is desirable that
there be no solid matter in
the stomach when
chloroform is administered,
it will be found very salutary
to give a cup of tea or beef-
tea about two hours
previously.”

4. DEFINITION- Prescribed period of time before
a PROCEDURE where patients
are not allowed the oral
intake of liquids or solids
 Preoperative fasting times
allow for gastric emptying
and reduction of aspiration risk

5. NULLA PER OS IN LATIN
NIL PER ORAL

6.  Reduce the occurrence of
pulmonary aspiration
WHAT IS PULMONARY ASPIRATION
 Aspiration of gastric contents occurring
after induction of anaesthesia,
during a procedure or in the immediate
period after surgery.

7. patient’s age
Patients size,
general medical condition,
scheduled time of surgery if it is known

8.  In 2011 ASA published updated Practice
Guidelines for Preop-Fasting and Pharmacologic
Intervention for the Prevention of Perioperative
Aspiration
 Guidelines deal with healthy patients of all ages

9.  PROLONGED FASTING
DEHYDRATION PATIENT DISSATISFACTION
HYPOGLYCEMIA
 pre-op fast does not guarantee an empty stomach
 timing of last fluid ingestion has little relation to
volume of gastric contents at induction

11. Clear fluids Breast milk Cow milk Solids
3 months 2 4 4 6
3-12 2 4 6 6
Child 2 - 6 6

12. Clear fluid includes
water,PEDIALYTE, fruit juice
Without pulp, carbonated
beverages,
Clear tea and black coffee
A clear liquid is a solution
(as opposed to a suspension)
that contains no particulate
matter.
Type of liquid ingested
important than volume
infants < 5 months 10 ml/kg
children and adults 15 ml/kg

13.  The fasting recommendations
for breast milk is 4hrs
 does contain milk solids
 cleared from the stomach
more quickly than nonhuman milk

15.  Allowing infants and children to have oral intake
closer to the time of surgery can help reduce patient
irritability, parental stress, and risk of dehydration
 Children are encouraged to have clear fluids up
to 2 hours before surgery.
 Rapid fluid turnover and high metabolic rate makes
dehydration and hypoglycaemia more likely in the
fasting child than potential aspiration.

16.  Children who have had unrestricted clear fluids until 2
hrs prior to surgery have residual gastric volumes equal
to or less than those fasted overnight
 younger the child, the smaller the glycogen stores;
therefore,the occurrence of hypoglycemia
 Good hydration may reduce post-operative nausea and
vomiting

17.  Who have not fasted the requisite length of time and
have sustained a severe injury during this period
 esophageal dysmotility
 Incompetent gastroesophageal sphincters
(gastroesophageal reflux diseases)
 delayed gastric emptying times
 abdominal conditions associated with ileus, vomiting, and
electrolyte disorders

18.  Diabetic autonomic nueropathy is the most common form
of nueropathy
 Diabetic gastroparesis is associated with increased risk
during GA
 GASTROPARESIS is caused by vagal degeneration
 AWAKE OR RSI IS NEEDED in patients with GASTROPARESIS

19.  Treated as having full stomach
At risk of aspiration of gastric contents DURING INDUCTION OF
GA
REASON
TAKEN FOOD JUST SWALLOWED BLOOD From
B4 INJURY DELAYED GASTRIC ORAL OR NASAL
EMPTYING injury
DUE TO STRESS
NON PARTICULATE ANTACIDS BEFORE INDUCTION OF
ANESTHESIA

20.  ALL PREGNANT WOMAN SHOULD UNDERGO A PRE-
OP EVALUATION REGARDLESS OF PLANNED
DELIVERY MODE OR TYPE OF ANESTHETIC
TECHNIQUE
 PREGNANT WOMEN WHO UNDERGO GA ARE AT
INCREASED RISK FOR MORTALITY FROM
PULMONARY ASPIRATION OF GASTRIC CONTENTS
 MORTALITY-5-15%
 TIMELY ADMINISTRATION OF NON-PARTICULATE
ANTACIDS
H2 RECEPTOR ANTAGONISTS AND OR
METOCLOPRAMIDE FOR ASPIRATION PROPHYLAXIS

21. CONTENTS
 HISTORY
 INTRODUCTION
 PRESENTATION
 DIAGNOSIS
 MANAGEMENT
 PREVENTION

22.  In 1946 Mendelson first
described aspiration pneumonitis
In pregnant woman undergoing
anesthesia
 Nitrous oxide and ether anaesthesia
administered by face mask for
operative delivery was complicated
by aspiration in 66 women from 44 016 maternities (0.15%)
between 1932 and 1945.
CURTIS LESTER MENDELSON

23.  Also known as ACID ASPIRATION SYNDROME
 This syndrome is due to the irritation of bronchioles
by gastric HCL, producing bronchiolar spasm,
a peribronchiolar exudates, and congestion.
 Aspiration of acidic and usually sterile gastric contents
into the lungs.
 Mendelson went on to show that acid was responsible for
this asthma-like syndrome

24.  EARLIEST AND MOST RELIABLE
SIGN OF ASPIRATION IS HYPOXEMIA
 presence of wheezing and ronchi,
which may be localised to one lung
 Aspiration of solid material causes
plugging of the large airways and is
often fatal.
 In those who aspirated liquid, a syndrome of dyspnoea,
cyanosis and tachycardia was observed.

25.  Bronchospasm, pulmonary oedema and ventilation
perfusion mismatch all contribute to worsening arterial
hypoxaemia
 patients were at risk of aspiration from the presence of
25 ml residual gastric volume (RGV) or volume > 0.3–0.4
ml/kg and pH>2.5
 Maximal pulmonary damage is achieved at an aspirate
pHvalue of 1.5
 Recovery after 24–36 h was universal

26.  PHASE-1-PROFOUND DYSPNEA AND
TACHYPNEA.BRONCHOSPASM IS OFTEN
PRESENT.CHEST X RAY NORMAL
 PHASE-2-LATENT PERIOD
INCREASED CYANOSIS AND HYPOXEMIA
MINOR CHEST X RAY ABNORMALITIES
 PHASE-3-RESPIRATORY FAILURE,PROFOUND
HYPOXEMIA
REDUCED COMPLIANCE
DIFFUSE BILATERAL INFILTRATES
 PHASE-4-HYPOXEMIA UNRESPONSIVE TO OXYGEN
METABOLIC AND RESPIRATORY ACIDOSIS

27.  Moderate amounts of aspiration will only present after
6-8 hrs
 Severe liquid aspiration may cause immediate collapse
 Suction through E T TUBE showing bile stained fluid is
often diagnostic
 Cxr and ABG are helpful in long term cases

28. mediastinal shift
densities are seen

29. CHEST X RAY OF A PATIENT WITH MENDELSONS SYN

30.  Tilt the operating table to a 30-degree head-down
position
 Larynx at a higher level than
the pharynx
 To allow gastric content to drain to the outside
 maintain cricoid pressure, suction the mouth and pharynx

31.  endotracheal intubation should be performed(if extubated)
immediate inflation of the endotracheal cuff to prevent
further aspiration
 Quickly suction through the endotracheal tube before
administering 100% oxygen by PPV
 orogastric tube should be inserted to empty the stomach
 pH value of the gastric content should be determined.
 Tracheobronchial aspirate is collected for culture and
sensitivity tests

32.  Only way to maintain adequate oxygenation is to institute
mechanical ventilation with 100% oxygen and the addition
of positive end-expiratory pressure
 Analysis of arterial blood gases should be performed to
determine the severity of hypoxemia
 Application of PEEP is recommended to improve pulmonary
function
 Membrane oxygenator may be indicated if paO2
CONTINUES TO FALL below 50mmHg

33.  Bronchial lavage is contraindicated and is likely to
aggravate the injury by removing or dispersing
surfactant
 Ultimate degree of pulmonary destructioncant be guaged
at the time of destruction
 Early diagnosis and appropraite management will
decrease mortality
 Role of steroids is controversial

34.  Pre-operative fasting guidelines
 Premedication with drugs which decrease risk
of aspiration
 Specialised induction techniques
 Gastric decompression by a wide bore
orogastric tube

36. ELECTIVE PROCEDURES
SEDATION REGIONAL GENERAL ANESTH
NIL BY MOUTH FROM MIDNIGHT
EMPTY STOMACH
DECREASE RISK OF REGURGITATION

37.  In the absence of c/i nasogastric drainage
should be used to reduce residual gastric
volume
 prior to induction of anaesthesia for patients
with bowel obstruction or paralytic ileus.
 Nasogastric tubes (NGT) REDUCE LOS tone
and may be associated with GER around the
tube.
 The presence of an NGT does not appear to
reduce the effectiveness of cricoid pressure
in cadaver studies.

38.  Basal skull fracture
 Severe midface trauma
 Recent nasal surgery
 Coagulopathy
 Oesophageal varices or stricture
 Recent banding or cautery of oesophageal varices
 Gastric bypass surgery

39.  Goal of aspiration prophylaxis
1)-to decrease gastric volume
2)-increase gastric pH

40.  Decrease risk of aspiration
 Routine use of drugs as prophylaxis is not recommended by
ASA guidelines
 Beneficial in
 full stomach patients
 Symptomatic GERD
 HIATAL HERNIA
 presence of NG TUBE
 MORBID OBESITY
 DIABETIS GASTROPARESIS
 PREGNANCY

41.  Empty the stomach by medication
 Apomorphine slow I .V of1-3mg is given until vomiting
occurs
 Then naloxane o.4 mg which will suppress vomiting
 Atropine and glycopyrrolate will control salivation,they
decrease gastric acid secretion but decrease los tone

42.  Dopamine D2 receptor antagonist
 Prokinetic agent that stimulates gastric motility
 Antiemetic
 Used to treat nausea GER AND DIABETIC GASTROPARESIS

44.  AGENTS USED
 IN OLDEN DAYS 0.3MOLAR SODIUM CITRATE 30ml
solution was used to nuetralise gastric contents
 Sodium citrate is a clear, soluble, non-particulate alkali.

45.  Effective at raising gastric pH, but may cause an increase
in gastric volume.
 Failure to neutralise gastric acidity in some patients may
be related to inadequate mixing with stomach contents
 Unfortunately, the DURATION OF ACTION of sodium citrate
is dependent on the rate of gastric emptying and may be
as short as 20 minutes, thereby not providing adequate
prophylaxis at the time of recovery.
 In some patients it is emetogenic.

46. H2 antagonists or proton pump inhibitors can
alter the volume and pH of gastric contents.
Timing of administration is important, a single
dose of ranitidine, lanzoprazole or rabeprazole
given a few hours before surgery reduces the
volume and acidity of gastric secretions.
Omeprazole needs to be given the night prior to
and on the morning of operation. There is no
evidence to support the routine use of these
drugs.

49.  MOST POTENT SUPPRESSORS OF GASTRIC ACID
SECRETION
 INHIBITORS OF H-K-ATPASE

50.  What equipment must be prepared and
checked prior to undertaking RSI?
 Anaesthetic machine and breathing circuit
 Routine patient monitoring applied
 Airway equipment
 Tipping trolley
 Suction switched on and immediately to hand
 Drugs – including emergency drugs
 A trained assistant

54. The application of cricoid pressure to prevent passive
regurgitation at induction of anaesthesia was proposed
by Sellick (1961).

55. ANATOMY
The cricoid cartilage is a ring-
shaped cartilage which when
pressed backwards onto the
vertebral column will occlude
the upper end of the
oesophagus
Applied with thumb and index
finger
Pressure of 25-30 newtons

56.  Elevating the patients chin
(without displacing cervical spine)
 Pushing the CRICOID CARTILAGE posteriorly to close
esophagus

57.  Lower oesophageal sphincter pressure decreases as
anaesthesia is induced
 cricoid pressure should, therefore be applied whilst the
patient is still awake and increased immediately
consciousness is lost
 Cricoid pressure should be maintained until the trachea
has been intubated, the cuff inflated and the correct
position of the tube confirmed

58.  Cricoid pressure should still be maintained if active
vomiting occurs
 BECAUSE risk of aspiration outweighs the potential risk of
oesophageal rupture from high intraoesophageal pressures
 Applying cricoid pressure is difficult in patients with short
and thick necks
 If pressure has been applied incorrectly the larynx may be
pushed away from the midline, making the process of
intubation difficult

60.  Worsen laryngoscopic View without providing
Effective prevention Of aspiration
 In case where the applied pressure is not central, there is a
risk of tracheal deviation
 A very high contact pressure can lead to a flattening of the
tracheal lumen
 If the operator applies the maneuver before the patient loses
consciousness, then the patient may cough which increased
intragastric pressure
 This method is strictly against in patients with acute
vomiting.

65.  5 point auscultation
 capnography
 Bilateral chest rise