Cook, Chest, 1991

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Gastric protection and pneumonia; does pH or drug choice matter ?

Raising gastric pH does not significantly increase the incidence of pneumonia in the critically ill. When compared with antacids and/or H2 blockers, Sucralfate, is only associated with a lower incidence of pneumonia. Overall however the standard of evidence is poor suggesting the need for a definitive study.

Level of evidence 1⁺.

Citation/s:
Nosocomial Pneumonia and the Role of Gastric pH. A Meta-Analysis
D.J. Cook, L.A. Laine, G.H. Guyatt, T.A. Rafin
Chest 1991; 100;1: 7-13
Lead author's name and fax: Dr D.J. Cook, Epidemiology and Biostatistics, McMaster University Medical Centre, Hamilton, Ontario, Canada L8N 3Z5

Three-part Clinical Question: Does the use of different drugs for stress ulcer prophylaxis have an effect on the incidence of pneumonia in the critically ill patient. Does targeting a specific gastric pH make a difference ?
Search Terms: Critically ill, pneumonia, ranitidine, sucralfate, meta-analysis

The Review:
Data Sources: : Medline, Embase, Citation Index, pharmaceutical companies, hand search, unpublished data by searching research directories, conference papers and Biosos Previews.
Study Selection: RCTs
Data Extraction: Critically ill patients. Comparison of one or more prophylactic drug with each other, or with placebo or control group. Outcome measure; nosocomial pneumonia. (8 studies)

The studies were multiple independent reviews of individual reports. They were tested for heterogeneity.

The Evidence:

Pneumonia: Prophylaxis Titrated to Gastric pH (>/= 3.5) vs no Titration	ICU discharge	0.14	0.63	34%	21
Outcome	Time to Outcome	Typical CER	Typical OR	RRR	NNT	p Value
	95% Confidence Intervals:		0.24 to 1.62		10 to -15
Pneumonia: pH-altering drugs vs Placebo/Control	ICU discharge	0.11	0.42	55%	16
Pneumonia: pH-altering drugs vs Placebo/Control	95% Confidence Intervals:		0.16 to 1.1		11 to -103
Pneumonia: Sucralfate vs pH altering drugs	ICU discharge	0.26	0.55	38%	10
Pneumonia: Sucralfate vs pH altering drugs	95% Confidence Intervals:		0.28 to 1.06		6 to -88

As you can see from the table all the odds ratios 95% CI'c cross the odds ratio of unity suggesting no significant difference.

Comments:
Conclusions of the authors were that:
(1) There was a trend in favour of reducing the incidence of pneumonia with pH-altering drugs in comparison to placebo or non-treated controls.
(2) When comparing pH-altering drugs with sucralfate there was a trend towards reduced pneumonia with sucralfate.
(3) There is no significant effect on the rate of pneumonia in patients receiving prophylactic therapy titrated to gastric pH.

Non-English papers were included.

In several of the trials examined the effects of antacids and H2 blockers were not examined separately. Most studies were of small size. All of these factors combine to prove the need for a large well conducted study to examine the effects of H2 blockers and antacids separately.

Appraised by: Chris Cairns, SPR in anaesthesia and intensive care. Intensive care Unit, Edinburgh Royal Infirmary; Sunday, April 28, 2002
Email: Chris.Cairns@btinternet.com
Kill or Update By: May 2005

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