期刊名称：General Internal Medicine and Clinical Innovations
电子版ISSN：2397-5237
出版年度：2016
卷号：1
期号：4
页码：67-70
DOI：10.15761-GIMCI.1000121
语种：English
出版社：Open Access Text
摘要：Endogenous digoxin-like factors (EDLF) are compounds that promote natriuresis, inhibit sodium-potasium-ATPase, and cross-react with antibodies raised against cardiac glycosides. Although EDLF are well described in experimental animal models and a variety of clinical conditions in humans, no investigation previously evaluated an association between EDLF and hypothermia. We used two separate models to examine the presence of EDLF in hypothermic humans.The first study consisted of a case-controlled comparison of patients with unintentional environmental hypothermia. All patients with environmental hypothermia were prospectively enrolled if they were not taking cardiac glycosides and had no conditions previously associated with EDLF. A digoxin concentration obtained at presentation was compared to one obtained from presentation on patients from a demographically matched control group of normothermic patients. The second study enrolled a convenience sample of patients undergoing controlled cold cardioplegia for surgery. Once again, patients were excluded for conditions previously associated with EDLF, and were required to have a non-detectable preoperative digoxin concentration. Digoxin concentrations were subsequently compared in the pre- and post-operative periods. In addition to serving as their own controls, a comparison group of normothermic patients were added to help control for confounding factors associated with surgery under general anesthesia.Twenty-two patients with environmental hypothermia (mean temperature 91° Fahrenheit, range, 83.8-93.8° Fahrenheit) and 22 controls were included in the first study. Ten hypothermic patients had measurable digoxin concentrations, 6 of which were above 0.15 ng/mL. All control patients had digoxin concentrations of 0.00 ng/mL (p = 0.03, Fisher's exact test). The second study enrolled ten patients undergoing surgery with cold cardioplegia and ten control patients undergoing normothermic surgery under general anesthesia. None of the ten control patients had measurable digoxin concentrations on either pre or postoperative testing. Although all of the cold cardioplegia hypothermic patients had negative preoperative digoxin concentrations, one developed a postoperative concentration of 0.44 ng/mL. We conclude that hypothermia is associated with the presence of EDLF. An animal model and further human testing will be required to establish causation.
