anal fistula (fistula in aÂ´no) one opening on the cutaneous surface near the anus, which may or may not communicate with the rectum. arteriovenous fistula one between an artery and a vein, either pathologic (such as a varicose aneurysm) or surgically created to ensure an access site for hemodialysis.
1 millibar (or hectopascal/hPa), is equivalent to 0.02953 inches of mercury (Hg). It is therefore only necessary to multiply a reading in millibars by the latter figure, to achieve the required conversion. E.g. for 1023 mbar, multiply by 0.02953=30.21 inches.
This means if you have a pressure gauge reading 1 inch per mercury, it can be further split up into 25.4 millimeters of mercury. One advantage of mm/hg is that it provides a high level of accuracy. A measurement of 15 mm/hg is just 0.59 in/hg, which is a rather arbitrary method to express pressure. The second advantage of using millimeters of mercury, is that it provides a solid range of integers to represent a relatively low pressure.