Urinary tract infections in spinal cord injury: prevention and treatment guidelines.

OBJECTIVES AND METHODS: The literature on prevention and therapy of urinary tract infection (UTI) in patients with spinal cord injury (SCI) was reviewed using 3 levels of evidence. RESULTS: Antibiotic therapy is only indicated in symptomatic bacteriuria or in symptomatic exacerbations of chronic UTI. During the acute phase of a SCI, UTI's are more prevalent and bacteria are different and more resistant to antibiotics compared with the chronic phase of SCI. In SCI in general, routine screening urine cultures are not valuable as a high species turn over is seen. Intermittent catheterisation, tapping or Crédé manoeuvre coincide significantly with lower frequency of UTI compared to permanent catheter drainage. No measures are proven efficient in the long term in prevention of bacteriuria or UTI. Methenamine salts are perhaps useful in the prevention of UTI but not in patients with a permanent catheter (level III). Antibiotic prophylaxis was found useful in reducing asymptomatic bacteriuria but not in the prevention of symptomatic infections (level I). However, during prophylaxis a doubling of antibiotic resistance was found. In patients with augmented bladder antibiotic prophylaxis is useless (level II). In chronic SCI the first choice antibiotics are nitrofurantoin or trimethoprim, the second choice are fluoroquinolones (level III) whereas in acute SCI a higher resistance profile to antibiotics is frequent and therefore fluoroquinolones or cefuroxime are suggested (level III). There is no consensus in the literature but we suggest 5 days of antibiotic treatment in UTI during chronic SCI without fever, 7 days in acute SCI without fever and a minimum of 14 days in patients with UTI and fever (level III).

Critical haemoglobin concentration in anaesthetized dogs: comparison of two plasma substitutes.

We have explored systemic and regional tolerance to haemodilution during anaesthesia with two different synthetic colloids. Eighteen dogs undergoing mechanical ventilation during anaesthesia with ketamine were submitted to progressive normovolaemic haemodilution with either gelatin (GEL; n = 9) or hydroxyethylstarch (HES; n = 9) administered on a 1:1 ratio. Systemic oxygen delivery was calculated from measurement of thermodilution cardiac output and arterial oxygen content, while systemic oxygen consumption was determined from expired gas analysis. Mesenteric oxygen delivery and consumption were determined using ultrasonic flow measurements, and arterial and mesenteric venous oxygen contents. The critical haemoglobin concentration (i.e. the haemoglobin value below which oxygen consumption becomes oxygen delivery dependent) was mean 3.6 (SD 0.8) g dl-1 in the GEL and 3.5 (1.5) g dl-1 in the HES group. The mesenteric critical oxygen extraction ratio (O2ER) (GEL 50.1 (12.1)%; HES 48.5 (13.4)%) was significant lower than the systemic critical O2ER (GEL 66.1 (8.4)%; HES 67.7 (7.1)%). There were no significant differences between the GEL and HES groups for any of these variables, or in the amount of colloid administered. During the study, oxygen delivery decreased almost linearly with reduction in haemoglobin, indicating a lack of cardiac output response to anaemia during ketamine anaesthesia.