Doppler-guided goal-directed fluid therapy does not affect intestinal cell damage but increases global gastrointestinal perfusion in colorectal surgery: a randomized controlled trial.

AIM: Individualized, goal-directed fluid therapy (GDFT), based on Doppler measurements of stroke volume, has been proposed as a treatment strategy in terms of reducing complications, mortality and length of hospital stay in major bowel surgery. We studied the effect of Doppler-guided GDFT on intestinal damage as compared with standard postoperative fluid replacement. METHOD: Patients undergoing elective colorectal resection for malignancy were randomized either to standard intra- and postoperative fluid therapy or to standard fluid therapy with additional Doppler-guided GDFT. The primary outcome was intestinal epithelial cell damage measured by plasma levels of intestinal fatty acid-binding protein (I-FABP). Global gastrointestinal perfusion was measured by gastric tonometry, expressed as regional (gastric) minus arterial CO2 -gap (Pr-a CO2 -gap). RESULTS: I-FABP levels were not significantly different between the intervention group and the control group (respectively, 440.8 (251.6) pg/ml and 522.4 (759.9) pg/ml, P = 0.67). Mean areas under the curve (AUCs) of intra-operative Pr-a CO2 -gaps were significantly lower in the intervention group than in the control group (P = 0.01), indicating better global gastrointestinal perfusion in the intervention group. Moreover, the mean intra-operative Pr-a CO2 -gap peak in the intervention group was 0.5 (1.0) kPa, which was significantly lower than the mean peak in the control group, of 1.4 (1.4) kPa (P = 0.03). CONCLUSION: Doppler-guided GDFT during and in the first hours after elective colorectal surgery for malignancy increases global gastrointestinal perfusion, as measured by Pr-a CO2 -gap.

Comparison of the effects of dexmedetomidine and esmolol on myocardial oxygen consumption in dogs.

BACKGROUND AND OBJECTIVE: The beta-adrenergic blocker esmolol and the alpha 2-adrenergic agonist dexmedetomidine have the potential to decrease perioperative myocardial ischaemia. The pathophysiological mechanisms involved in these anti-ischaemic properties have not been thoroughly studied. We compared the effects of esmolol and dexmedetomidine on two indices of overall myocardial oxygen demand and on directly measured myocardial oxygen consumption of the left anterior coronary artery territory. METHODS: Eleven mongrel dogs were instrumented to measure aortic and left ventricular pressure, aortic and left anterior coronary artery flow and myocardial wall thickening. Variables related to myocardial oxygen metabolism were also determined. Measurements were performed during four sequential experimental conditions in each dog (Control 1: esmolol; Control 2: dexmedetomidine). RESULTS: Esmolol and dexmedetomidine decreased haemodynamic indices of myocardial oxygen demand to a similar extent: esmolol decreased the rate-pressure product by 16+/-3% and the pressure-work index (PWI) by 16+/-3%, dexmedetomidine decreased the rate-pressure product by 26+/-3% and the PWI by 16+/-7%. However, these similar decreases resulted from different haemodynamic effects of the two study drugs. Dexmedetomidine had a more pronounced bradycardic effect than esmolol (P = 0.01) and increased systolic aortic pressure (SAP) by 15+/-4% while esmolol decreased SAP by 8+/-2% (P < 0.01). dP/dt(max) and regional myocardial area decrease were lower after esmolol than after dexmedetomidine. Neither drug had an effect on myocardial oxygen consumption. CONCLUSIONS: Esmolol and dexmedetomidine decreased two haemodynamic indices of overall myocardial oxygen demand to a similar extent but neither drug decreased directly measured myocardial oxygen consumption in the territory of the left anterior descending artery.

Catheter-related epidural abscesses -- don't wait for neurological deficits.

Epidural abscess is a rare but serious complication of epidural anesthesia for peri- and postoperative analgesia. It is feared because of possible persistent neurological deficits. Epidural abscess presents mostly with a classic triad of symptoms: back pain, fever and variable neurological signs and symptoms. When neurologic signs or symptoms develop, MRI scanning is the diagnostic procedure of choice. The therapy of choice is intravenous antibiotics for more than 4 weeks with or without a laminectomy or drainage. In the present paper we describe three patients with epidural abscesses presented during a time period of 1 year in our hospital. In each case, patients developed local signs of infection and systemic signs, but no neurological symptoms. Based on these cases and a review of the literature, we propose that MRI scanning should be strongly considered when patients present with systemic and local signs, even in the absence of neurological deficits.

The effects of alpha 2-adrenergic stimulation with mivazerol on myocardial blood flow and function during coronary artery stenosis in anesthetized dogs.

The central sympatholytic effect of alpha 2 agonists may be beneficial during myocardial ischemia, but could be opposed by their peripheral vasoconstrictive effect. We studied the effects of mivazerol during periods of moderate coronary artery stenosis in anesthetized dogs. Mivazerol decreased heart rate (from 125 +/- 6 to 106 +/- 6 bpm) and cardiac output (from 4.4 +/- 0.6 to 1.8 +/- 0.2L/min) under normal conditions, while mean arterial pressure did not change. Mivazerol reduced blood flow in nonischemic myocardium and in the ischemic epicardial layer, but blood flow was preserved in the ischemic midmyocardial and subendocardial layer. Mivazerol had no effect on myocardial oxygen extraction during the stenoses, and regional myocardial oxygen consumption was unchanged. However, mivazerol decreased myocardial oxygen demand from 4.51 +/- 0.51 to 3.17 +/- 0.24 mumol.min-1.g-1, thereby reducing oxygen deficiency of ischemic myocardium to values significantly lower than in the placebo group (from 1.07 +/- 0.32 to 0.47 +/- 0.41 mumol.min-1.g-1). Mivazerol had no effect on myocardial lactate production during the stenoses. We conclude that mivazerol reduced myocardial oxygen demand while blood flow was preserved in the inner layers of ischemic myocardium.

Fluorescent microspheres to measure organ perfusion: validation of a simplified sample processing technique.

A disadvantage of nonradioactive microsphere techniques is that the processing of samples is time-consuming and complex. We developed and validated a simplified processing method for the fluorescent microsphere (FM) technique. In seven anesthetized dogs with coronary artery stenosis up to six different FM and five different radioactivity labeled microspheres (RM) were injected. Two FM and two RM labels were injected simultaneously to enable inter- and intramethod comparison. After gamma-counting samples of blood, myocardium (n = 168), and other organs (n = 59) were digested in test tubes with 2 N ethanolic KOH (60 degrees C, 48 h), microspheres were sedimented by centrifugation, dye was extracted in the same tube, and fluorescence was measured. With this processing method, recovery of FM was approximately 100%. Good correlations for inter- and intramethod comparisons were found [r = 0.985 +/- 0.01 (mean +/- SD)]. The lower intermethod correlation for blue microspheres (r = 0.958) indicates that the use of this label is less desirable. RM and FM endocardial-to-epicardial blood flow ratios correlated well (r = 0.974). With this one-vessel centrifugal sedimentation method and at least five fluorescently labeled microspheres, blood flow can be reliably measured in various organs, including ischemic myocardium.

Amnesic syndrome caused by neurosarcoidosis.

A 20-year-old woman presented with subacute amnesia, which turned out to have been caused by neurosarcoidosis. The patient showed several remarkable features: isolated bilateral temporal hydrocephalus, caused by ventriculitis/arachnoiditis; spinal arachnoiditis as demonstrated by myelography, which was not noticed on MR scan. Diagnostic difficulties that are sometimes encountered when neurosarcoidosis is suspected (particularly the differentiation from neurotuberculosis if insufficient evidence of systemic sarcoidosis is found) are discussed.

4-Hydroxycoumarin oral anticoagulants: pharmacokinetics-response relationship.

The blood coagulating factors II and VII and prothrombin times (Thrombotest) were followed during a dosage interval (= 24 h) in patients on acenocoumarol (n = 6) and on phenprocoumon (n = 6) therapy. The patients were on stable anticoagulation (%TT: 7-13%) for at least 6 months. The study was performed to investigate the concentration-response relationship of the 4-hydroxycoumarin-type oral anticoagulants. The three parameters were stable during the 24-h interval for patients on phenprocoumon therapy. Patients on acenoumarol showed fluctuations in their factor VII levels; peak activities were observed at about 2 h, trough activities at about 16 h after acenocoumarol intake. Factor II and Thrombotest activities were stable. Plasma levels of phenprocoumon were stable during daytime whereas acenocoumarol levels declined exponentially (t1/2 about 12 h). The results indicate the oral anticoagulants to exhibit a concentration-response relationship common to drug-receptor interactions. The results also suggest that for stable and long-lasting anticoagulant therapy oral anticoagulants with half-lives beyond the dosage interval (t1/2 greater than 24 h) should be preferred.