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ABSTRACT: CONTEXT: Although low preoperative haemoglobin (Hb) concentration is a well known risk factor for adverse outcome, little is known about decreases in Hb and postoperative Hb concentrations. OBJECTIVES: The aim of this study was to evaluate the prognostic impact of both pre- and postoperative Hb concentrations (divided into low, intermediate and high tertiles) as well as Hb decrease, defined as preoperative minus postoperative Hb (g dl), on postoperative cardiovascular events in vascular surgery patients. DESIGN: An observational cohort study. SETTING: Erasmus University Medical Centre, Rotterdam, the Netherlands, from 1 January 2002 to 31 December 2011. PATIENTS: One thousand four hundred and eighty-four patients underwent elective open or endovascular abdominal aortic repair (aneurysm or stenosis), lower extremity arterial repair or carotid surgery. Patients for whom pre or postoperative Hb concentrations were not available were excluded. MAIN OUTCOME MEASURES: The study endpoint was 30-day postoperative cardiovascular events, including myocardial infarction, heart failure, arrhythmias, stroke, asymptomatic troponin-T release and cardiovascular death. RESULTS: In 1041 patients, both pre and postoperative Hb concentrations were available. Thirty-day cardiovascular events occurred in 221 (21%) patients. Multivariable logistic regression analyses, adjusting for age, sex, Revised Cardiac Risk Index (high-risk surgery, coronary heart disease, heart failure, cerebrovascular disease, diabetes mellitus, renal insufficiency), hypertension and hypercholesterolaemia, demonstrated that low preoperative Hb (8.7 to 12.9 g dl) was associated with 30-day events [odds ratio (OR) 1.7; 95% confidence interval (CI) 1.1 to 2.5]. Intermediate (10.6 to 12.1 g dl) and low (7.4 to 10.5 g dl) postoperative Hb and Hb decrease were also associated with an independently increased risk of 30-day events (intermediate Hb: OR 1.7; 95% CI 1.1 to 2.7; low Hb: OR 3.1; 95% CI 2.0 to 4.8; and Hb decrease: OR 1.2; 95% CI 1.1 to 1.3, respectively). Sensitivity analyses excluding patients with transfusions (n = 314) demonstrated that only postoperative Hb concentrations remained associated with a high risk of 30-day cardiovascular events (intermediate Hb: OR 1.8; 95% CI 1.0 to 3.3 and low Hb: OR 2.0; 95% CI 1.0 to 4.0). CONCLUSION: Pre and postoperative Hb concentrations and Hb decrease are all related to 30-day cardiovascular events in elective vascular surgery patients. Postoperative Hb concentrations are the strongest predictor of 30-day cardiovascular events.
European Journal of Anaesthesiology 06/2013; · 2.23 Impact Factor
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ABSTRACT: Mitochondrial oxygen tension can be measured in vivo by means of oxygen-dependent quenching of delayed fluorescence of protoporphyrin IX (PpIX). Here we demonstrate that mitochondrial PO(2) (mitoPO(2)) can be measured in the skin of a rat after topical application of the PpIX precursor 5-aminolevulinic acid (ALA). Calibration of mitoPO(2) measurements was done by comparison with simultaneous measurements of the cutaneous microvascular PO(2) This was done under three different conditions: in normal skin tissue, in nonrespiration skin tissue due to the application of cyanide, and in anoxic skin tissue after the ventilation with 100% nitrogen. The results of this study show that it is feasible to measure the mitoPO(2) after the topical application of ALA cream by means of the PpIX-triplet state lifetime technique.
Optics Letters 07/2012; 37(13):2625-7. · 3.40 Impact Factor
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ABSTRACT: Measurement of tissue oxygenation is a complex task and various techniques have led to a wide range of tissue PO(2) values and contradictory results. Tissue is compartmentalized in microcirculation, interstitium and intracellular space and current techniques are biased towards a certain compartment. Simultaneous oxygen measurements in various compartments might be of great benefit for our understanding of determinants of tissue oxygenation. Here we report simultaneous measurement of microvascular PO(2) (μPO(2) ) and mitochondrial PO(2) (mitoPO(2) ) in rats. The μPO(2) measurements are based on oxygen-dependent quenching of phosphorescence of the near-infrared phosphor Oxyphor G2. The mitoPO(2) measurements are based on oxygen-dependent quenching of delayed fluorescence of protoporphyrin IX (PpIX). Favorable spectral properties of these porphyrins allow simultaneous measurement of the delayed luminescence lifetimes. A dedicated fiber-based time-domain setup consisting of a tunable pulsed laser, 2 red-sensitive gated photomultiplier tubes and a simultaneous sampling data-acquisition system is described in detail. The absence of cross talk between the channels is shown and the feasibility of simultaneous μPO(2) and mitoPO(2) measurements is demonstrated in rat liver in vivo. It is anticipated that this novel approach will greatly contribute to our understanding of tissue oxygenation in physiological and pathological circumstances.
Journal of Biophotonics 11/2011; 5(2):140-51. · 4.34 Impact Factor
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ABSTRACT: Mitochondrial oxygen tension can be measured in vivo by means of oxygen-dependent quenching of delayed fluorescence of protoporphyrin IX (PpIX). Here we demonstrate that delayed fluorescence is readily observed from skin in rat and man after topical application of the PpIX precursor 5-aminolevulinic acid (ALA). Delayed fluorescence lifetimes respond to changes in inspired oxygen fraction and blood supply. The signals contain lifetime distributions and the fitting of rectangular distributions to the data appears more adequate than mono-exponential fitting. The use of topically applied ALA for delayed fluorescence lifetime measurements might pave the way for clinical use of this technique.
Journal of Biophotonics 07/2011; 4(10):731-9. · 4.34 Impact Factor
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ABSTRACT: Postherpetic neuralgia is the most frequent complication of herpes zoster. Treatment of this neuropathic pain syndrome is difficult and often disappointing. We assessed the effectiveness of a single epidural injection of steroids and local anaesthetics for prevention of postherpetic neuralgia in older patients with herpes zoster.
We randomly assigned 598 patients older than 50 years, with acute herpes zoster (rash <7 days) below dermatome C6, to receive either standard therapy (oral antivirals and analgesics) or standard therapy with one additional epidural injection of 80 mg methylprednisolone acetate and 10 mg bupivacaine. The primary endpoint was the proportion of patients with zoster-associated pain 1 month after inclusion. Analyses were by intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN32866390.
At 1 month, 137 (48%) patients in the epidural group reported pain compared with 164 (58%) in the control group (relative risk [RR] 0.83, 95% CI 0.71-0.97, p=0.02). After 3 months these values were 58 (21%) and 63 (24%) respectively (0.89, 0.65-1.21, p=0.47) and, at 6 months, 39 (15%) and 44 (17%; 0.85, 0.57-1.13, p=0.43). We detected no subgroups in which the relative risk for pain 1 month after inclusion substantially differed from the overall estimate. No patient had major adverse events related to epidural injection.
A single epidural injection of steroids and local anaesthetics in the acute phase of herpes zoster has a modest effect in reducing zoster-associated pain for 1 month. This treatment is not effective for prevention of long-term postherpetic neuralgia.
The Lancet 02/2006; 367(9506):219-24. · 38.28 Impact Factor
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Pain 03/2004; 107(3):202-6. · 5.78 Impact Factor
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ABSTRACT: Radiofrequency facet denervation procedures are widely used for the treatment of chronic low-back pain. Currently, both temperature-controlled and voltage-controlled techniques are used. In this combined in vivo and in vitro study, the electrophysiologic consequences and the effects on lesion size of these techniques were determined.
Thirty-three patients were randomly assigned to receive a lumbar radiofrequency facet denervation by using either temperature-controlled (80 degrees C, 60 seconds) or voltage-controlled (20 V, 60 s) mode. Electrophysiologic parameters in both groups during radiofrequency lesioning were registered. Observed differences between electrodes were quantified and interpreted, using lesion-size data from egg-white experiments.
Seventeen patients in the temperature group were treated with a total of 55 radiofrequency lesions, all considered technically adequate. In the voltage-controlled group, 16 patients received 63 lesions. Of these, 44 (69.8%) procedures were found to be technically inadequate. Voltage-controlled radiofrequency lesioning resulted in uncontrollable fluctuations of temperature, with resultant uncontrollable variations in lesion size. Temperature-controlled mode created reproducible lesion sizes.
There is no consistent relation between voltage and the temperature obtained during radiofrequency lumbar facet denervation. Temperature-controlled radiofrequency lesioning is preferred to create reproducible lesion sizes.
Regional Anesthesia and Pain Medicine 29(5):400-7. · 4.08 Impact Factor
