Raidal S L, Love D N, Bailey G D
Department of Veterinary Pathology, University of Sydney, New South Wales.
Aust Vet J. 1995 Feb;72(2):45-50. doi: 10.1111/j.1751-0813.1995.tb15328.x.
Confinement of horses with their heads elevated for periods up to 24 hours was used to evaluate the extent and the effects of bacterial contamination of the equine lower respiratory tract. Significant (P < 0.05) increases in bacterial numbers (up to 10(9) colony forming units/mL in transtracheal aspirate derived samples) occurred within 6 or 12 hours in most horses. Pasteurella/Actinobacillus spp and Streptococcus spp were most commonly isolated. Lowering of the head for 30 minutes every 6 hours to facilitate postural drainage did not prevent multiplication of organisms to levels equivalent to those achieved by horses where the head was elevated for 24 hours. When horses were released from confinement and heads were no longer maintained in an elevated position, clearance of accumulated secretions and bacteria occurred within 8 to 12 hours. Thus, confinement with the head elevated resulted in significant bacterial contamination and multiplication within the lower respiratory tract during a period often encountered in routine management procedures, such as transportation. The clearance of accumulated secretions occurred over a prolonged period after release from such confinement.
将马的头部抬高长达24小时以评估马下呼吸道细菌污染的程度和影响。大多数马在6或12小时内细菌数量显著增加（经气管抽吸物样本中高达10⁹菌落形成单位/毫升）（P<0.05）。最常分离出巴氏杆菌/放线杆菌属和链球菌属。每6小时将头部降低30分钟以促进体位引流并不能防止微生物繁殖到与头部抬高24小时的马所达到的水平相当的程度。当马从限制中释放且头部不再保持抬高位置时，在8至12小时内积聚的分泌物和细菌会清除。因此，在常规管理程序（如运输）中经常遇到的一段时间内，头部抬高的限制导致下呼吸道内显著的细菌污染和繁殖。从这种限制中释放后，积聚分泌物的清除会持续较长时间。
