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Additive risks of ventilation and renal failure. Benefit of feeding and ranitidine.

Citation/s: Cook DJ et al for The Canadian Clinical Trials Group. Risk Factors for Clinically important upper Gastrointestinal bleeding in patients requiring mechanical ventilation. Critical Care Medicine. 1999;27(12):2812-2817

Lead author's name and fax: Deborah J Cook. McMaster University, Hamilton, Ontario, Canada.

Three-part Clinical Question: What is the incidence of Clinically important Upper BI haemorrhage in ventilated critical care patients. In these patients what are the main risk factors associated with bleeding.

Search Terms: Critical care, ranitidine, sucralfate, RCT, Human, English

The Study: Cohort study. Double blinded, randomised.

The Study Patients: 1077 critically ill patients ventilated for at least 48 hours. The patients were sampled from 16 university-affiliated ICUs in Canada. The patient were randomized to receive sucralfate or ranitidine. Exclusions: admitting diagnosis of GI bleed, pneumonia, gastrectomy, predicted survival of less than 72 hours, more than 2 previous doses of stress ulcer prophylaxis.

Prognostic Factor: APACHE II score, MOD score (Six domains; cardiovascular, pulmonary, renal, hepatic, haematological, CNS. Coagulation data was not collected, therefore its impact on GI bleeding was not examined.

The Outcome: Death. Pneumonia or clinically important bleeding before ICU discharge. Definition of Gastrointestinal bleeding All patients were monitored for clinical signs of overt bleeding, including haematemesis, NG aspirate containing blood or coffee ground material, malena or pr bleeding. Clinically important bleeding was defined as overt bleeding plus of the following, in the absence of another cause: (1) a spontaneous drop of 20mmHg or more in the systolic or diastolic blood pressure within 24hrs of a gastrointestinal haemorrhage, (2) an increase in the pulse rate of more than 20bpm and an decrease in the SBP of more than 10mmHg on the patient assuming an upright position, (3) a decrease in Hb of a least 2g/dl in 24hrs and the transfusion of 2 units of packed red cells within 24hrs after bleeding, (4) failure of the Hb conc. to increase after transfusion by at least the number of units transfused minus 2.
There was a well-defined sample at a uniform (early) stage of illness. Follow-up was long enough; follow-up was complete. There were blind, objective outcome criteria. Adjustment was made for other prognostic factors. Can't tell if there was validation in an independent test-set of patients.

The evidence: Univariable regression

Prognostic Factor	Outcome	Result	Measure	Confidence Interval
Platelet Count < 50,000	Bleed in ICU	2.58	OR	1.19-5.57
Maximum MOD score	Bleed in ICU	1.11	OR	1.01 - 1.21
Renal Domain of MOD score	Bleed in ICU	1.46	OR	1.14 - 1.87
Pulmonary Domain of MODs	Bleed in ICU	1.56	OR	0.99 - 2.47
Hepatic Domain of MOD score	Bleed in ICU	1.37	OR	1.04 - 1.77

The Evidence: Multivariable regression

Prognostic Factor	Outcome	Result	Measure	Confidence Interval	Independent?
Maximum serum Creatinine	GI bleed in ICU	2.58	OR	1.16 - 1.32	yes
Enteral nutrition	GI bleed in ICU	0.3	OR	0.13 - 0.67	yes
Ranitidine administration	GI bleed in ICU	0.39	OR	0.17 - 0.83	yes

Comments:

Sucralfate did not significantly reduce the risk of bleeding. Ranitidine was superior to sucralfate in unfed, partially fed and fully fed patients.

A well conducted study with a large patient population. Ventilated patients who develop organ failure are at increase risk of GI bleeding. This is particularly the case for renal failure. This risk can be reduced by enteral feeding and the administration of ranitidine.

Quite correctly the authors suggest that the impact of enteral feeding and ranitidine should be compared in a large randomized controlled trial.

Appraised by: Dr Chris Cairns, Spr in Anaesthetics & Intensive Care, Edinburgh Royal Infirmary; Monday, December 23, 2002
Email: Chris.Cairns@btinternet.com
Kill or Update By: Dec 2007

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