Hospitalised adults with pneumonia are frequently misclassified as another diagnosis.

Using data from a large randomised controlled trial of adults hospitalised with acute respiratory illness, we examined the reliability of pneumonia diagnosis on discharge documentation. 50 (28.2%) of 177 patients with a pneumonia diagnosis had no radiological evidence of pneumonia. 67 (34.9%) of 192 patients with clinico-radiological evidence of pneumonia did not have a diagnosis of pneumonia listed; 'COPD exacerbation' or 'lower respiratory tract infection' was often listed instead. These patients more frequently had a respiratory comorbidity and lower oxygen saturations, CRP and temperature at presentation. Pneumonia diagnoses misclassification on discharge documentation may have clinical, financial, and research data implications.

Novel hydration assessment techniques employing thirst and a water intake challenge in healthy men.

Exploring novel hydration indices is important because no human biomarker has been shown to be incontrovertibly valid in all life situations. The present investigation was designed to identify inexpensive, nontechnical methods to use when self-assessing hydration status. This investigation evaluated the validity and efficacy of 2 novel techniques (i.e., thirst sensation and urine volume) to assess hydration state of 29 active men (mean ± SD; age, 23 ± 4 years; body mass, 76.02 ± 11.94 kg) at rest. Eight combinations of 4 water challenges (4.8, 9.3, 11.0, or 14 mL·kg(-1)) and 2 hydration states (mildly hypohydrated (HY), -2.0%; euhydrated (EU), -0.2% body mass) were employed. First, thirst was linearly related to body water loss, and ratings of thirst distinguished HY from EU (p < 0.001) subsequent to 19 h of controlled food and fluid intake. Second, measurements of urine volume 60 min after consuming a water bolus (11.0 or 14 mL·kg(-1)) were strongly and inversely correlated with entering hydration state, assessed by urine specific gravity (r(2) = 0.76, p < 0.0001) and urine osmolality (r(2) = 0.77, p < 0.0001). We concluded that healthy men can employ simple measurements of morning thirst sensation and urine volume to identify the presence of mild hypohydration and to guide fluid replacement. These 2 techniques are relevant because HY (-2% body mass) is the approximate threshold for the onset of thirst, reduced endurance exercise performance, and decrements of working memory and mood.

No effect of 5% hypohydration on running economy of competitive runners at 23 degrees C.

PURPOSE: Although running economy (RE) is recognized as an integral component of successful endurance performance and is affected by numerous factors, little is known about the influence of body water loss on RE. This investigation examined the effects of hypohydration (HY) on RE and associated physiological responses. METHODS: Ten highly trained collegiate distance runners (mean +/- SD; age, 20 +/- 3 yr; height, 178.5 +/- 6.3 cm; body mass, 66.7 +/- 5.4 kg; VO2max, 66.5 +/- 4.1 mL x kg(-1) x min(-1)) participated in four experiments on separate days, twice in a euhydrated (EU) and twice in a HY state (-5.5 and -5.7% body mass loss achieved during 24 h). At each hydration level, subjects performed one 10-min treadmill run per day (23 degrees C environment), at either 70% VO2max (EU 70% or HY 70%) or 85% VO2max (EU 85% or HY 85%) in a randomized, repeated-measures design. Cardiopulmonary, metabolic, thermal, hormonal, and perceptual variables were measured. RESULTS: No between-treatment differences existed for RE (EU 70%, 46.3 +/- 3.2; HY 70%, 47.2 +/- 3.8; EU 85%, 58.6 +/- 2.8; HY 85%, 58.9 +/- 4.1 mL x kg(-1) x min(-1)), postexercise plasma lactate concentration (EU 70%, 1.9 +/- 0.6; HY 70%, 1.8 +/- 0.6; EU 85%, 6.5 +/- 3.5; HY 85%, 6.4 +/- 3.5 mmol x L(-1)), or rating of perceived exertion. HY resulted in a greater (P < 0.05 to 0.001) heart rate (HR), rectal temperature, and plasma norepinephrine concentration (NE), concurrent with reduced cardiac output, stroke volume, and respiratory exchange ratio. CONCLUSION: HY did not alter the RE or lactate accumulation of endurance athletes during 10 min of exercise at 70 and 85% VO2max. These findings indicate that HY had no effect on RE, but that it increased physiological strain in a 23 degrees C environment.

Hydration assessment techniques.

Water in the human body is essential for metabolism, temperature regulation, and numerous other physiological processes that are consistent with good health. Accurate, precise, and reliable methods to assess body fluid compartments are needed. This review describes the hydration assessment techniques of isotope dilution, neutron activation analysis, bioelectrical impedance, body mass change, thirst, tracer appearance, hematologic indices, and urinary markers. It also provides guidance for selecting techniques that are appropriate for use with unique individuals and situations.