Advising patients to increase fluid intake for treating acute respiratory infections
Abstract
Background
Acute respiratory infection is a common reason for people to present for medical care. Advice to increase fluid intake is a frequent treatment recommendation. Attributed benefits of fluids include replacing increased insensible fluid losses, correcting dehydration from reduced intake and reducing the viscosity of mucus. However, there are theoretical reasons for increased fluid intake to cause harm. Anti‐diuretic hormone secretion is increased in lower respiratory tract infections of various aetiologies. This systematic examination of the evidence sought to determine the benefit versus harm from increasing fluid intake.
Objectives
To answer the following questions.
(1) Does recommending increased fluid intake as a treatment for acute respiratory infections improve duration and severity of symptoms?
(2) Are there adverse effects from recommending increased fluids in people with acute respiratory infections?
(3) Are any benefits or harms related to site of infection (upper or lower respiratory tract) or a different severity of illness?
Search methods
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2005, issue 2) which contains the Acute Respiratory Tract infection Group's Specialized Register, MEDLINE (1966 to July Week 1, 2005), EMBASE (1974 to Week 29, 2005), Current Contents (current 5 years) and CINAHL (1982 to July week 3 2005). Reference lists of articles identified were searched, and experts in the relevant disciplines were contacted.
Selection criteria
Randomised controlled trials (RCTs) that examined the effect of increasing fluid intake in people with acute respiratory infections.
Data collection and analysis
Each author assessed the identified studies to determine eligibility for inclusion.
Main results
No RCTs assessing the effect of increasing fluid intake in acute respiratory infections were found.
Authors' conclusions
There is currently no evidence for or against the recommendation to increase fluids in acute respiratory infections. The implications for fluid management in acute respiratory infections have not been studied in any RCTs to date. Some non‐experimental (observational) studies report that increasing fluid intake in acute respiratory infections may cause harm. RCTs need to be done to determine the true effect of this very common medical advice.
PICOs
Plain language summary
Advising patients to increase fluid intake for treating acute respiratory infections
Doctors commonly recommend that people with acute respiratory infections drink extra fluids. Acute infections include colds, acute sinusitis, tonsillitis, laryngitis, bronchitis, pneumonia and influenza. This review intended to find out the benefit or harm from this recommendation. Possible benefits of fluids are to replace fluid lost because of fever or rapid breathing, treat dehydration and reduce the viscosity of mucus. Possible harmful effects might be a dilution of the blood sodium concentration, leading to headache, confusion and seizures. This review found no evidence for or against the use of increased fluids in acute respiratory infections. No randomised controlled trials have been conducted to determine the benefit or harm from extra fluids. It is important that further studies be done in order to determine the true effect of this very common medical advice.
