ABSTRACT
Enhanced potassium ion permeability at the enterocyte basolateral membrane is assumed to facilitate sustained chloride ion and fluid secretion into the intestinal lumen during episodes of secretory diarrhoeal disease. To examine this concept in vivo, two potassium ion channel blockers and a channel opener were coperfused with E. coli heat stable STa enterotoxin to determine whether such compounds improved or worsened the inhibited fluid absorption. In the STa (80 ng/mL) challenged jejunal loop, the fluid absorption rate of 28.6 ± 5.8 (14) µL/cm/hr was significantly below (P < .001) the normal rate of 98.8 ± 6.2 (17) µL/cm/hr. Intraluminal (300 uM) glibenclamide added to STa perfused loops failed to improve the inhibited fluid absorption rate, which was 7.4 ± 3.2 (6) µL/cm/hr on coperfusion with STa. Similarly, on coperfusion with 30 uM clotrimazole, the fluid absorption rate with STa present remained inhibited at 11.4 ± 7.0 (4) µL/cm/hr. On coperfusion with intraluminal 1 uM cromakalim, STa reduced fluid absorption significantly (P < .02) to 24.7 ± 8.0 (10) µL/cm/hr, no different from STa challenge in the absence of cromakalim. Infusion i.v. with these agents also failed to restore fluid absorption after STa challenge. These observations do not support the proposed potassium ion permeability event as a necessary corollary of enterotoxin-mediated secretion. This makes it unlikely that modulators of such permeability prevent enterocyte secretion in diarrhoeal disease.
ABSTRACT
OBJECTIVE: To compare the two-finger versus the two-thumb method of chest compression on an infant model. STUDY: an unblinded, prospective, cross-over experimental study. SETTING: the metropolitan area of a city with a population of greater than 260,000. PARTICIPANTS: pediatric medical personnel and emergency workers. Anyone unable to complete the study was excluded. INTERVENTIONS: participants performed chest compressions on an infant mannikin for 2 min. PARTICIPANTS were randomized to use the two-finger method or the two-thumb method for the first minute. The investigators recorded the skillguide readings of green (correct), green and orange (too deep), red (wrong placement), or no light (too shallow). Sixty or more correct compressions were judged to be adequate. RESULTS: Two hundred and nine participants completed the study. PARTICIPANTS included: 66 nurses, 45 EMTs, 38 physicians, 27 paramedics, 14 nurse's assistants/emergency department technicians, 10 firefighters, five respiratory therapists, and four students. Seventy-one percent (149/209) of participants failed to give adequate compressions by either method. Only 40 participants performed adequate compressions using the two-thumb method (95% confidence interval. 14-25%). Thirty-eight participants gave adequate compressions using the two-finger method (95% confidence interval, 13-24%). No statistically significant difference existed between the two groups (P = 0.877; the McNemar test). A statistically significant difference was found in the number of shallow compressions for each method. Forty participants (19.1%) had more than 40 compressions that were too shallow versus 15 (7.2%) using the two-thumb method (P < 0.005). CONCLUSIONS: Medical personnel often fail to give adequate compressions. The two-thumb method was as adequate as the two-finger method. Overall, more compressions were measured as shallow with the two-finger method.