Nutrition Support In Mechanical Ventilated

Patients

Pranithi Hongsprabhas MD.

Swallowing function Oral phase

Preparation &movement of food from oral cavity to pharynx

Pharyngeal phase Soft palate rises to close nasal

cavity Vocal cords adducts Epiglottis tilts and shields larynx Respiration is temporarily

inhibited Pharynx contracts

esophageal phase upper esophageal sphincter

relaxes peristalsis

The most dreaded complication of tube feedings is tracheobronchial

aspiration of gastric content

Tube feeding associated aspiration

The most serious complication of ENClinically unimportant to respiratory

failure Clinically silent or cough, choking to

ARDS

Aspiration categories

Oropharygeal bacteriaInert fluid, particulateAcidified gastric contents

Wynne JW et al. Ann Intern Med 1977, 87:486

Prevalence and mortality

Prevalence Varies 70% in depressed

consciousness 22% in ICU 50-75% in ET

intubation 0-40 % EN

associated

Mortality62% in witness

aspiration40% with 1-lobe,

90% with 2 or more

Gastric aspiration:

Risk factors for aspiration

Naso/oral enteral intubationTracheal intubationEnteral tube feedingIncreased age with physiologic

insultGastroparesisGastroesophageal reflux (GER)

Risk factors for aspiration

Decreased level of consciousness (LOC)

Anesthesia Neurological disorderSeizureSupine position

Impaired level of consciousness

StrokeHead injurySedationAnesthesia

Impaired ability to protect airway

Cough and gag LES GET

Regurgitation and dysphagia

Increased risk of aspiration

Cough and gag reflexes

Absence or presence of gag reflex: not influence the risk of aspiration

Cough reflex may or may not prevent aspiration

diminished cough or gag reflexes are not reliable indicators or aspiration risk

Nasal or oral feeding tubes

Increased oropharyngeal secretions Impairment of laryngeal elevationDisruption of UES, LES Increased GER (75 vs. 35%)*,

aspiration

*Ibanez J. et al.JPEN 1992;16:419

Gastric vs. small bowel feeding

Controversy Early study : SB feeding less aspiration Later study : not confirm

ASPEN 2005

Acute brain injury Impaired gastric function: delayed GET Impaired LES: regurgitationPost pyloric feeding: more preferred

Jejunal feeding Better tolerate Less reflux

Gleghon E. et al. Neurologic diseases in: ASPEN manual 2005: -246255.

Size of NG-NE tube

Children: Less GER in Fr8 vs Fr10-12

Adult No significant different in GER,

aspiration rate

Ferrer M. et al.Ann Int Med 19992;130:991

Malposition of feeding tube

Faulty initial placementUpward dislocation

Increased risk when tube ports in or near esophagus

Need to confirm feeding tube position

Enteral feeding schedule

Bolus vs. continuous feedingBolus: higher aspiration risk

Decreased LES intragastric pressure

Intermittent vs. continuous

33.3%

16.67% 17.647%

5.89%

0

5

10

15

20

25

30

35

Ciocon study Kocan study

IntermittentContinuous

Asp

iratio

n ra

te (

%)

Tracheal intubation /MV

Reduce upper airway defense Cough Desensitization of pharynx and larynx Laryngeal m atrophy

Esophageal compression Increase abdominal pressure: GER Sedation

increased risk after 48 hr. and 1%/day in MV

Vomiting

Increased risk of aspiration Forceful entry of gastric content into

oropharynx Displacement of feeding tube

Sedation increases risk of vomiting

Regurgitation and dysphagia

Increased risk of aspiration

Cough and gag reflexes

Absence or presence of gag reflex: not influence the risk of aspiration

Cough reflex may or may not prevent aspiration

diminished cough or gag reflexes are not reliable indicators or aspiration risk

Body position

Supine position: associated with more aspiration

Less aspiration with elevation of head of bed 30-45° during EN feeding

Position and GER/aspiration

Aspiration: supine vs. semirecumbent MV patients* Semirecumbent decreases GER compare to supine#

*Torres A et al: Ann Int Med 1992;116:540-3

4154 cpm

954 cpm

68%

32%

0

10

20

30

40

50

60

70

Radioactive Culture

Supine

Semirecumbent

#Orozco-Levi et al. Am J Respi Crit Care 1995;152:1387

Position and Pneumonia

0

5

10

15

20

25

Drakulovic et al Kollef et al

Supine Semirecumbent

Recognizing patients at risk of AP

Decreased LOCTracheal intubationMVNG, NEMajor abdominal and thoracic

trauma/surgeryDMAdvance age

Gastric residual volume (GRV)

HistoryUnderlying rationale Inherent flaws in the rationale Inherent flaws in the practiceClinical pattern of GRVEvidence of correlation of GRV with

ENEvidence of GRV and aspiratiom

Gastric residual volume (GRV)

GRV >150-200 ml Fluid in stomach:

3000/d ~125ml/hr

50 ml???? Use less GRV: receive

nutrient lessGRV and risk of

aspiration: controversy

GI Secretion (ml)

Saliva 1000

Gastric 2000

Pancreatic 2000

Bile 1000

Small bowel 1000

Reach colon 600-1500

The Washington Manual of Surgery. Chapter14

Clinical pattern of GRV

GRV>100 GRV>150 GRV>200

Normal volunteers

40% (11%) 15% (2.4%) 0% (0%)

Critically ill NG

50% (27.4%)

50% (13.1%)

30% (4.3%)

Critically ill PEG

25% (2.5%) 0% (0%) 0% (0%)

McClave SA, et al. JPEN 1992;16:99

Correlation of GRV with ETF

Change in ETF rate change in GRVGRV increases at the initial but

decreases as feeds continueBolus generate more GRVGRV obtained from NG>gastrostomy

GRV and aspiration: Pro

GRV>500, 2

consecutive GRV150-500, or

vomiting, 43%

without intolerace,

24%

0%

10%

20%

30%

40%

50%

Mentec H. Critical Care Med 2001;29:1955-61.

P=0.01

GRV<100 ml, 33.4

>2 GRV>=150ml,

46.6

>2GRV>=200ml, 44.2

0

10

20

30

40

50

Evidence of aspiration (gastric pepsin)Metheney NA. JPEN2005;29:S10.

P=0.020

P=0.018

Incidence of regurgitation by range of GRV

GRV 0-50

GRV 51-100

GRV101-150

GRV151-200

GRV201-299

GRV300-399

GRV400+

P-value

Regurgit-tion

28.7%

(439)

41.0%

(39)

29.4%

(17)

35.7%

(14)

33.3%

(9)

40.0%

(5)

37.5%

(8)

0.134

Aspiration 22.8%

(501

23.7%

(38)

26.7%

(15)

20.0%

(10)

0.0%

(10)

40.0%

(5)

25.0%

(8)

0.412

GRV and aspiration: Cons

Paracetamol absorption test (GET): no difference in GRV McClave 2005: found no difference in aspiration (using

yellow dye) in GRV<150 ml vs.>150 ml, and >400 ml

GRV 0-50

GRV 51-100

GRV101-150

GRV151-200

GRV201-299

GRV300-399

GRV400+

P-value

Regurgit-tion

28.7%

(439)

41.0%

(39)

29.4%

(17)

35.7%

(14)

33.3%

(9)

40.0%

(5)

37.5%

(8)

0.134

Aspiration 22.8%

(501

23.7%

(38)

26.7%

(15)

20.0%

(10)

0.0%

(10)

40.0%

(5)

25.0%

(8)

0.412

GRV and aspiration: Cons

Lukan JK. AJCN 2002;75:417S

35%

27.80%21.6%

22.6%

0

5

10

15

20

25

30

35

Regurgitation Aspiration

GRV> 200 mlGRV 400 ml

Prevention

Head of bed elevation 30-45°Verify tube placementGastric aspirate: GRVEvaluate GI intolerance

GI intolerance

Abdominal discomfortBowel movementAbdominal distentionBowel soundGRVTrend to increased GRV Trend to

increased GRVRadiography

Conclusion

Identify the risk patientsPrevention

Verify tube placement position Position: head of bed elevation Avoid bolus feeding