Post on 12-Jan-2016
Pre-operative Starvation Times
Ayngara Thillaivasan
Background
Reason for pre-operative starvation is to try to prevent aspiration of stomach contents during anaesthesia.
Mendelson’s Syndrome
1946. New York Obstetrician. Face mask anaesthesia: Ether & Nitrous Oxide.
Aspiration in 66 out of 44016 women. 2 Deaths from airway obstruction from solid food. Liquid aspiration lead to a syndrome of dyspnoea,
cyanosis and tachycardia. (All recovered.)
Gastric Contents
Volume & pH of gastric contents. Determined by oral intake, gastric secretion &
emptying.
Experiments in 1974: Patients at risk of aspiration pneumonitis from the presence of 25mls of residual gastric volume of pH <2.5.
Entire contents would have to reach the lungs.
50% of healthy fasted people: >25ml & pH~2.
Gastric Emptying
William Beaumont, American army surgeon. Canadian fur trapper with a gunshot wound to the
stomach. Permanent gastric fistula.
Water: Exponential process. Half life ~10 mins. 95% clear liquids gone in 1 hr.
Solids: Constant. Starts 1 hr after ingestion. 50% of a meal is at the duodenum in 2hrs.
Risk Factors For Aspiration
Emergency procedures. Light anaesthesia. GI pathology. Obesity. Opiods. Neurological disease. Lithotomy position. Difficult intubation. Reflux disease. Hiatus hernia.
ASA Task Force Guidelines 1999.
10 anaesthesiologists in both private and academic practice from America and Canada.
“Not intended as standards or absolute requirements.”
“The guidelines provide basic recommendations that are supported by analysis of current literature and by a synthesis of expert opinion, open forum commentary, and clinical feasibility data.”
Guidelines(Accepted by the AAGBI.)
“2-4-6 (?8) Rule”.– 2 hours for clear fluid.– 4 hours for breast milk.– 6 hours for solids and non-human milk.
Preoperative assessment… Routine use of GI stimulants, gastric acid secretion
blockers, antacids, antiemetics, anticholinergics, and multiple agents is NOT recommended.
Audit
Responses
158 Audit forms. – X2: No induction times.– X4: No actual starvation times.
496 cases ~ 31%
X1: Cancelled. (Not starved for procedure.)
Specialties 1
SPECIALITY URGENCY ORAL RANGE AVERAGE
Neuro/CF Elect (5) Water 2hr 20 – 20hr 10* 5hr 24*
Food 14hr 0 – 16hr 0 14hr 53
Breast 20hr 10*
Urg (2) Water 4hr 50 – 6hr 10 5hr 30
Food 12hr 25
Bottle 12hr 50
Card/Angio Elect (11) Water 2hr 0 – 14hr 0 4hr 39
Food 7hr 30 – 15hr 20 10hr 33
Breast 11hr 45
Bottle 8hr 15 – 8hr 30 8 hr 23
Specialties 2
SPECIALITY URGENCY ORAL RANGE AVERAGE
Eyes Elect (16) Water 2hr 0 – 7hr 40 3hr 41
Food 8hr 10 – 17hr 25 12hr 33
Breast 7hr 0 – 12hr 15 9hr 38
Bottle 6hr 0 – 10hr 5 8hr 1
Urology Elect (13) Water 2hr 0 – 7hr 15 4hr 15
Food 6hr 0 – 19hr 0 12hr 15
Breast 11hr 45
Bottle 8hr 10 – 8hr 25 8hr 18
Urg (1) Water 9hr 50
Food 9hr 50
Specialties 3
SPECIALITY URGENCY ORAL RANGE AVERAGE
Gen/Liver Elect (13) Water 2hr 0 – 11hr 0 3hr 58
Food 7hr 0 – 15hr 40 12hr 36
Bottle 6hr 5 – 6hr 30 6hr 18
Urg (3) Water 3hr 15 – 27hr 5 12hr 33
Food 6hr 45 – 27hr 5 16hr 55
T&O Elect (5) Water 3hr 20 – 6hr 30 4hr 55
Food 6hr 5 – 11hr 30 8hr 13
Bottle 8hr 10 – 8hr 50 8hr 30
Urg (4) Water 2hr 30 – 12hr 30 6hr 15
Food 12hr 10 – 14hr 0 13hr 15
Specialties 4
SPECIALITY URGENCY ORAL RANGE AVERAGE
B&P Elect (13) Water 2hr 35 – 5hr 0 3hr 52
Food 5hr 45 – 17hr 30 12hr 25
Breast 4hr 05
Bottle 7hr 30 – 17hr 15 12hr 5
Urg (5) Water 4hr 15 – 6hr 10 5hr 24
Food 12hr 10 – 15hr 20 13hr 55
ENT Elect (19) Water 2hr 15 – 15hr 45 7hr 4
Food 8hr 10 – 18hr 0 15hr 22
Urg (1) Water 2hr 45
Food 18hr 45
Specialties 5
SPECIALITY URGENCY ORAL RANGE AVERAGE
MRI Elective (9) Water 2hr 0 – 14hr 30 5hr 6
Food 6hr 30 18hr 15 13hr 6
Breast 15hr 30
Bottle 14hr 0
Urgent (1) Water 3hr 15
Food 15hr 45
Dental Elective (5) Water 2hr 30 – 13hr 0 8hr 51
Food 11hr 0 – 13hr 0 12hr 15
Gastro Elective (4) Water 4hr 30 – 15hr 50 11hr 21
Specialties 6
SPECIALITY URGENCY ORAL RANGE AVERAGE
Oncology Elect (16) Water 2hr 40 – 16hr 0 7hr 18
Food 12hr 50 – 21hr 0 16hr 5
Breast 7hr 40
Bottle 5hr 45 – 9hr 10 7hr 28
Urg (2) Water 8hr 15 – 15hr 15 11hr 45
Food 8hr 15 – 15hr 15 11hr 45
Total
ORAL ELECTIVE URGENT
WATER 5hr 52 7hr 8
FOOD 12hr 45 13hr 59
BREAST 9hr 8
BOTTLE 10hr 4 12hr 50
League Table (Elective)
BEST WORST
WATER Eyes Gastro
FOOD T&O Oncology
BREAST B&P MRI
BOTTLE General MRI
Reasons
3
11
3
4
3
8
0 2 4 6 8 10 12
1
Bed too early
Awake too late
Didn't want anything inmorining
Didn't understand/adhere toinstructions
Prolongued NBM
Other
Lists
AM PM ALLDAY
WATER 2hr 0 – 16hr 0
Av: 6hr 33
2hr – 7hr 15
Av: 3 hr 43
2hr 0 – 14hr 0
Av: 4hr 2
FOOD 8hr 15 – 21hr 0
Av: 14hr 44
6hr 5 – 19hr 0
Av: 11hr 13
5hr 45 – 16hr 0
Av: 11hr 5
BREAST 4hr 5 – 15hr 30
Av: 6hr 45
11hr 45
BOTTLE 5hr 45 – 17hr 15
Av: 9 hr 19
6hr 15 – 7hr 30
Av: 6hr 53
6hr 20 – 12hr 50
8hr 36
Position On List
AM PM ALLDAY
ST MID END ST MID END ST MID END
WATER 6hr 3 6hr 49
6hr 54
3hr 21 3hr 48
4hr 33
2hr 58
5hr 12
5hr 0
FOOD 13hr 46
15hr 8
15hr 51
11hr 40
12hr55
8hr 38
14hr 7
10hr 33
8hr 50
BREAST 5hr 42 11hr 48
11hr 45
11hr 45
BOTTLE 7hr 43 10hr 37
11hr 35
6hr 15 7hr 30
8hr 20
8hr 25
8 hr 46
List Changes
107
14
20
1
8
2
10
No Change
No Order
Up
Cancelled
Down
Insufficient Starvation
List Changes 2
42
1 13
1
43
1
1
12
2
1
12
5 11
2
6
1
1
0
2
4
6
8
10
12
Cardiol
ogy
Dental
ENT
Gastro
Gener
alM
RI
Neuro
Oncolo
gy
Ophth
almolog
y
Plastic
s
Urolog
y
Overrunning
Down
Up
List Changes 3
DOWN OVER
RUNNING
NO CHANGES
UP
WATER 5hr 49 8hr 1 5hr 17 6hr 5
FOOD 14hr 43 14hr 40 12hr 53 13hr 45
BREAST 15hr 30 15hr 30 9hr 45 5hr 53
BOTTLE 10hr 15 7hr 55 7hr 46 12hr 23
Conclusions
Insufficient starvation is not a major problem. Starvation times are for the most part greatly in excess
of what is needed. Slight difference between elective and urgent cases. AM lists lead to prolonged starvation times. Medical lists are worse than surgical for starvation
times. Altered / overrunning lists have longer starvation times.
Recommendations
Limited for prehospital.– Make sure parents
understand.– Encourage them to follow as
fully as possible.– ?Anaesthetic information?
Discuss with teams. Early & realistic decisions
when lists are changing/overrunning.
ONCOLOGY.