Effect of perfusion pressure on the splanchnic circulation after CPB: a pilot study.

BACKGROUND: The impact of different blood pressure targets is unknown for post cardiac surgery patient in the intensive care unit. We, therefore, investigated the effects of a mean arterial pressure (MAP) target of 65 or 85 mmHg on splanchnic oxygenation, metabolic function, cytokine regulation and gastric tonometry after cardiopulmonary bypass. METHODS: Sixteen patients were randomized to the HLH group (high-low-high) where MAP of 85-65-85 mmHg was targeted or the LHL group where MAP 65-85-65 mmHg was targeted with norepinephrine infusion. RESULTS: MAP targets were achieved in all patients at all timepoints (64 ± 3, 84 ± 4; 65 ± 5, LHL group; vs. 84 ± 3; 66 ± 2; 85 ± 5 mmHg, HLH group). At corresponding timepoints, hepatic venous saturation was 41 ± 15%; 58 ± 24%; 56 ± 21% in the LHL group vs. 50 ± 19%; 43 ± 20%; 41 ± 18% in the HLH group (P<0.05). No changes were observed in cardiac output, global or trans-splanchnic lactate levels and cytokine levels or in gastric tonometry CO2. CONCLUSION: Achieving a MAP target of 85 mmHg by means of norepinephrine infusion after CPB appears safe for the splanchnic circulation.

Pilot alternating treatment design study of the splanchnic metabolic effects of two mean arterial pressure targets during cardiopulmonary bypass.

BACKGROUND: The arterial pressure target for optimal splanchnic function during cardiopulmonary bypass (CPB) is uncertain. Thus, we aimed to compare the effects of two different arterial pressure targets during CPB on trans-splanchnic oxygenation, acid-base regulation, and splanchnic interleukin-6 (IL-6) and interleukin-10 (IL-10) flux. METHODS: Sixteen patients undergoing cardiac surgery with CPB in a university affiliated hospital were subjected to a prospective alternating treatment design interventional study. We measured arterial and hepatic vein blood gases, electrolytes, IL-6, and IL-10 while targeting a mean arterial pressure (MAP) of between 60 and 65 mm Hg for 30 min, a MAP of between 80 and 85 mm Hg for 30 min (using norepinephrine infusion), and finally 60-65 mm Hg MAP target for 30 min. RESULTS: The MAP targets were achieved in all patients [65 (4), 84 (4), and 64 (3) mm Hg, respectively; P<0.001] with a greater dose of norepinephrine infusion during the higher MAP target (P<0.001). With longer time on CPB, hepatic vein O2 saturation decreased, while magnesium, lactate, glucose, IL-6, and IL-10 increased independent of MAP target. The decrease in hepatic vein saturation was greater as the temperature increased (re-warming). Overall, there was trans-splanchnic oxygen, chloride, lactate, and IL-6 removal during CPB (P<0.001) and carbon dioxide, bicarbonate, glucose, and IL-10 release (P<0.001). Such removal or release was not affected by the MAP target. CONCLUSIONS: Targeting of a higher MAP during CPB by means of norepinephrine infusion did not affect splanchnic oxygenation, splanchnic acid-base regulation, or splanchnic IL-6 or IL-10 fluxes. Australian and New Zealand Clinical Trial Registry ACTRN 12611001107910.

Effect of an education programme on the utilization of a medical emergency team in a teaching hospital.

BACKGROUND: Medical Emergency Teams (MET) have been developed to identify, review and manage acutely unwell ward patients. Previous studies have suggested that there may be obstacles to the utilization and activation of the MET. AIMS: To determine the effect of a detailed education programme on the rate of utilization of the MET system 3.5 years after its introduction in a University teaching hospital. METHODS: Prospective interventional study involving a detailed programme of education, feedback and decision support for nursing and medical staff given before, during and after implementation of a MET system. We measured the number of MET calls per month for both medical and surgical patients for 109 250 consecutive admissions to the acute care campus of Austin Health from August 2000 to June 2004. RESULTS: Overall activation of the MET increased from 25 calls per month to a peak of 79 calls per month over the study period (average increase of one MET call/month). After standardization for monthly admissions, the increase in MET utilization for surgical patients (increase by 1.13 MET/1000 admissions/month) was 4.9-fold greater than for medical patients (increase by 0.23 MET/1000 admissions/month; P < 0.0001). At the peak level of activity (April 2004), the MET was called to review 8.4% of surgical and 2.7% of medical admissions (P < 0.0001). CONCLUSIONS: There was a progressive increase in the utilization of the MET service in the 3.5 years after implementation, with the rate of uptake 4.9 times greater for surgical than for medical patients. Sustained uptake of the MET system is possible, but increased utilization may take several years to develop. Short-term studies testing the efficacy of the MET system are likely to significantly underestimate its effect on reducing adverse events. Intensive care unit resource adjustments will become necessary to meet increased demand.