Role of the gut in the development of multiple organ dysfunction

Correlation between early sublingual small vessel density and late blood lactate level in critically ill surgical patients

BACKGROUND

Surgical stress may cause excessive inflammation and lead to microcirculatory dysfunction. The hypothesis of this study was that early microcirculatory dysfunction may result in anaerobic glycolysis and lead to elevated blood lactate levels in patients admitted to surgical intensive care units.

METHODS

This prospective observational study enrolled adult patients admitted to surgical intensive care units after general surgery or thoracic surgery. We measured blood lactate levels before the operation and at 1 h and 24 h after the operation. We obtained images of sublingual microcirculation using a sidestream dark field video microscope and analyzed them employing automated analysis software.

RESULTS

A total of 31 patients completed the study. Perioperative total and perfused small vessel densities were lower in patients with a blood lactate level ≥3 mmol/L. We observed a significant correlation between the total small vessel density at 1 h and the blood lactate level at 24 h (r = -0.573; P = 0.001). In addition, we saw a significant correlation between the perfused small vessel density at 1 h and the blood lactate level at 24 h (r = -0.476; P = 0.008).

CONCLUSIONS

Early total and perfused small vessel density may be used as an early predictor or therapeutic goal for critically ill surgical patients in further studies.

Gastrointestinal complications after aortic surgery

BACKGROUND AND PURPOSE

A major gastrointestinal complication (GIC) after aortic surgery may be disastrous, but these complications have received scant attention. This study was performed to determine the risk factors, associated events, and outcomes for patients with GIC.

METHODS

We performed a secondary analysis of a prospective study that examined 120 consecutive patients who underwent transperitoneal aortic revascularization for aneurysmal or occlusive disease.

RESULTS

The following 29 GICs developed in 25 patients (21%) within 30 days of aortic surgery: paralytic ileus that required replacement of nasogastric tubes (n = 12), upper gastrointestinal bleeding (n = 5), Clostridium difficile enterocolitis (n = 5), acute cholecystitis (n = 2), mechanical obstruction (n = 2), ascites (n = 2), and colon ischemia (n = 1). Seven patients required operations for GICs after aortic revascularization. A comparison of patients with and without GICs showed no differences in the prevalence of risk factors, presence of mesenteric artery stenoses, coexisting medical illnesses, antecedent gastrointestinal history, operative indication, preoperative fluid administration, or duration of operation. However, patients with GICs had more intraoperative complications (P = .004), greater intraoperative blood loss (P = .02), and more fluids during the postoperative period (P = .008). The mean duration of mechanical ventilation was 71 +/- 23 hours for patients with GICs versus 7 +/- 2 hours for patients without GICs (P = .006). A higher prevalence of pulmonary (P = .004) and renal (P = .001) complications was seen in the patients with GICs. The mean stay in the intensive care unit was 16 +/- 2 days for patients with GICs as compared with 5 +/- 0.4 days for patients without GICs (P < .001). Four deaths occurred, all caused by multisystem organ failure: 3 patients had GICs, and 1 did not have a GIC (P = .007).

CONCLUSIONS

These results show that GICs are prevalent in transperitoneal aortic surgery and are associated with severe morbidity rates, increased hospital costs because of prolonged stay, and increased mortality rates. Some GICs appear to be associated with intraoperative events that lead to visceral hypoperfusion, and others can be attributed to mechanical causes. However, none of the variables examined in this study were predictive of GICs. In all, GICs should be considered serious adverse sequela after aortic revascularization. Because no risk factors for GICs have been identified, these complications currently cannot be prevented.