Passage survival of European and American eels at Francis and propeller turbines.

We present the magnitude of losses of European eel Anguilla anguilla and American eel A. rostrata in passage through propeller and Francis turbines at hydroelectric projects. Survival and injury rates and types were turbine type related. Overall, eel survival was higher (mean ± 90% CI = 95.1 ± 5.3%,) and injury rate lower (12.5 ± 10.5) at Francis than propeller turbines (survival = 80.7 ± 6.4%; injury rate = 25.7 ± 7.9%). The common injury type at Francis turbines was bruises and at propeller turbines was severance. Blade shape and thickness of the leading edge of the blades (rounded, thick buckets of Francis turbines v. flatter, sharper edged blades in propeller turbines); eel entry routes into the turbines; their flexible, cylindrical body shape and orientation probably contributed to these differences. Relationship between survival and injury and turbine characteristics was turbine specific. For Francis turbines, one negative correlation (r = -0.986, P < 0.01) between survival and runner speed was found and two positive correlations between injury rates and fish length (r = 0.740, P < 0.10) and number of blades (r = 0.835, P < 0.05) were noted for propeller turbines. Several severely injured eels remained active 48 h after turbine passage suggesting caution is warranted when using telemetric movement for estimating eel survival. We conclude there is a need to (a) better understand travel paths and approach orientation of eels through turbines; (b) determine where only eel passage is of concern at hydropower plants that have both turbine types and therefore preferential operation of Francis turbines may be considered; (c) inform hydropower plant operators where turbine replacement is being considered and downstream eel passage is of concern that replacement by Francis or bulb turbines may prove beneficial for eel passage.

Emergency colectomy for fulminant Clostridium difficile colitis: Striking the right balance.

The number of reported cases of Clostridium difficile (CD) infections has increased markedly worldwide. CD causes a spectrum of clinical syndromes, ranging from mild diarrhea to a very severe illness in the form of pseudomembranous colitis (PMC), toxic megacolon, leading to colonic perforation, peritonitis, and even death. In today's practice, toxic megacolon is more often caused by pseudomembranous colitis than ulcerative colitis. There is urgent need to establish clear guidelines about how and when to refer patients with fulminant CD colitis to surgeons. Furthermore, there is no strict protocol for the timing of surgical intervention. The aim of this review is to review the available evidence about the criteria for referral to surgeons and timing for surgery. Medline search was carried out for articles published on fulminant CD colitis with emergency colectomy from 1966 to 2010. There were no prospective randomized trails. All retrospective cohort and case control studies were included. We excluded case reports, letters, and studies with less than five patients. Our search showed that patients with confirmed or suspected CD who failed to respond to maximum medical therapy and develop three of the following should be referral for surgical assessment: abdominal pain, abdominal distension, localized tenderness, pyrexia >38°C, and tachycardia >100 beats per minute. In addition to the above, if the patient is above 65 years old and develops four of the following, they should be considered for an emergency colectomy: WBC >16 × 109/l, lactate >2.2 mmol/l, albumin <30 g/l, blood pressure <90 mm Hg, CT/endoscopy evidence of severe colitis in spite of maximum anti-clostridial therapy. Colectomy still carries a high mortality rate; however, timely surgical intervention in fulminant CD colitis (FCDC) prevents many deaths in selected cases. In the absence of published prospective multicenter trial, we suggest that our criteria may enhance early diagnosis and consideration of early referral for surgery. Ultimately, this may reduce the significant morbidity and mortality associated with FCDC.