Validation of a personal fluid loss monitor.

Dehydration raises heat injury risk and reduces performance [ , , ]. The purpose was to validate the Hydra-Alert Jr (Acumen). The Hydra-Alert was tested in two exercise/clothing conditions. Participants wore it while wearing exercise clothing and exercising at a self-selected intensity (n = 8). Others wore the Hydra-Alert while wearing a ballistic-vest and performing an industrial-protocol (n = 8). For each condition, the Hydra-Alert was tested on two occasions (T1 and T2). The Hydra-Alert was tested against nude weight loss for both conditions. The Hydra-Alert had low test-retest reliability for both conditions (average absolute value of the error between Hydra-Alert outputs of T1 and T2 = 0.08 +/- 0.08 percentage points). With exercise-clothing, the Hydra-Alert evidenced low-moderate correlations between percent nude weight loss and Hydra-Alert output at 20 min (r = 0.59-T1, p = 0.13; r = 0.12-T2, p = 0.78), at 40 min (r = 0.93-T1, p = 0.001; r = 0.63-T2, p = 0.10), and at approximately 2 % weight loss (r = 0.21-T1 and T2, p = 0.61 and 0.62, respectively). The correlation at 40 min during T1 fell during T2 suggesting the Hydra-Alert was inconsistent. When wearing a ballistic-vest, the Hydra-Alert had poor validity (T1: r = - 0.29 [p = 0.48] for weight loss vs. monitor; T2: r = 0.11 [p = 0.80]). At the higher levels of dehydration ( approximately 2 %), the Hydra-Alert error was so high as to render its readings of little value. In some cases, the Hydra-Alert could lead to a false level of security if dehydrated. Therefore, the Hydra-Alert is of little use for those who want to measure their fluid loss while exercising in the heat.

A coronary care unit in a small hospital.

The first effective breakthrough in the treatment of coronary thrombosis occurred with the realization that the arrhythmias were a major factor in the high mortality figures.Drugs have been used to control anomalous rhythms with considerable success for a number of years. A safe and very effective instrument was added to our armamentarium by the discovery of an electrical defibrillator, soon combined with the monitor, pacemaker and synchronizer.To use this equipment more intelligently and effectively the attending personnel require extra training in the recognition and prompt treatment of arrhythmias, mouth to mouth breathing, external cardiac massage, the use of the cardiac monitor and defibrillation unit, etc.During the course of their illness, at least 75 percent of all patients who have suffered a myocardial infarction, develop significant arrhythmias. Early recognition and control of benign disturbances of rhythm will frequently prevent the occurrence of major arrhythmias. It is in this area that recent developments have opened a vista in which we can hope to witness a change in the alarming mortality figures of myocardial infarction.The author gives a statistical resumé of his Unit's experience with 98 patients.