RENAL PROBLEMS AND CRITICAL CARE  Solution 5

She is treated with 1 litre of hextend (6% hydroxyethyl starch buffered in Ringer’s lactate) , her CVP rises to 14cmH2O, she puts out little urine, and her blood pressure remains 90/50 mmHg (MAP 63). The resident starts a norepinephrine infusion, targeted at a MAP of >80mmHg, and the patient’s urinary output increases to 70 to 100ml/hour. Over the next 48 hours, each time the vasopressor was weaned and the MAP fell below 75mmHg, so too did the urinary output. Eventually, the patients blood pressure recovers, and she is weaned from ventilation and vasopressors without further difficulty. The cause of the vasoplegia was considered to be release of inflammatory mediators (particularly inducible nitric oxide synthetase) due to fecal soiling.

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The surgical chief resident was annoyed that this patient did not have a pulmonary artery catheter placed, what do you think?

Unless the low urinary output is due to poor cardiac performance, there is little to be learned by using right heart catheterization: the same information can be gleaned less invasively using echocardiography. If there is concern that this patient had a history of coronary arterial disease, and may have had a perioperative myocardial event, a stroke volume monitor may be useful.

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