In addition, there's connecting service from Canada, Europe, South America and the Far East. Commuter service between San Juan, St. Croix and St. Thomas is also available. Commuter airlines can transport you between islands in as little as 17 minutes.n addition, there's connecting service from Canada, Europe, South America and the Far East. Commuter service between San Juan, St. Croix and St. Thomas is also available. Commuter airlines can transport you between islands in as little as 17 minutes.
A rough estimate is that it takes about 14 hours for blood to be broken down within the intestinal lumen; therefore if transit time is less than 14 hours the patient will have hematochezia, and if greater than 14 hours the patient will exhibit melena.
In these situations, the blood is moving through the colon so rapidly that there is not enough time for the bacteria to turn the blood black. Sometimes, bleeding from the gastrointestinal tract can be too slow to cause either rectal bleeding or melena. In these patients, bleeding is occult (not visible to the naked eye). The blood is found only by testing the stool for blood (fecal occult blood testing) in the laboratory.