Efeitos da hipovolemia aguda leve no esvaziamento gÃstrico e na distribuiÃÃo intra-gÃstrica de lÃquidos em humanos sadios / Effects of acute mild hypovolemia in gastric emptying and intragastric distribution of liquid meal in healthy humans

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Introduction: Preliminary researches have shown that acute mild hypovolemia reduces tonus and increases gastric compliance in healthy humans. (Macedo et. al, Neurogastroenterol Mot, 2005). Aims: Then we purposed to investigate if, despite a mild hypovolemia, blood donation was able to delay gastric emptying and modify intragastric distribution of a liquid test meal in healthy volunteers. Methods: We studied 14 healthy men volunteers (median age 23 years and body mass index 24.1 kg/m2). After an overnight fast (8-10h), volunteers underwent randomized and paired studies on separate moments (7 to 21 days). After beginning of mean blood pressure and heart rate monitoration, they were submitted to venous punction followed (experimental condition) to a standard blood letting (up to 450-mL) or not (control condition). Next, they ingested 500-mL of the test meal (5% glucose solution labelled with 37MBq of Tecnecium - 99mTc). Serial images of the gastric area in anterior and posterior projections were taken by a gamma camera throughout 60 minutes. After definition of regions of interest for proximal, distal, and total stomach, the activity time curves were derived from geometric means of anterior and posterior counts. Statistical analysis was performed by paired âtâ test. Results: There is no significant difference of hemodynamic parameters between experimental and control conditions. In comparison with the respective control values, hypovolemia increased significantly the total stomach retention since 20 min (69.8 Â 2.9 vs 62.3 Â 2.3%) until 60 min (35.1 Â 2.1% vs 28.2 Â 2.9%) after intake meal (P<0,05). The t1/2 values obtained after bleeding (39.1Â3.5min) were greater than those in control (30.8Â2.6min) (P<0,05). In comparison with the respective control values, hypovolemia increased significantly the proximal stomach retention since 25 min (38.6Â2.4 vs 31.2Â2.2 %), until 60 min (18.6Â1.2 vs 12.3Â1.9%) after intake meal (P<0.05). There is no significant difference in distal stomach retention between both conditions. Conclusions: Besides mild hypovolemia, blood donation delays total gastric emptying and increases proximal gastric retention of a liquid meal in healthy volunteers.

ASSUNTO(S)

motilidade gastrointestinal volume sanguÃneo farmacologia hipovolemia

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