Biomedical subjects
Publications and source records attributed to S Winnock.
Acute lung injury is a common adverse effect of massive blood transfusion, responsible for 17% of the deaths due to transfusion in France. A cardiac origin is often suspected. We report a case of post-transfusional pulmonary oedema in a cirrhotic patient, which could be related to a non-cardiac and underdiagnosed aetiology: the so-called transfusion related acute lung injury (TRALI).
A predictive parameter of beta-lactam therapeutic efficacy is the time (T > MIC) while antibiotic serum concentrations are above the MIC of suspected bacteriological agents. This led us to carry out a randomised open study to compare the usually used intermittent administration of Tazocin (three injections of 4 g/0.5 g a day) and continuous perfusion of 12 g/1.5 g a day by calculating these T > MIC. Patients from digestive reanimation department were randomised within two arms: continuous or intermittent administration. Sixteen takings of blood were executed over a forty-hour period. After liquid/liquid extraction, piperacillin and tazobactam serum concentrations were determined by HPLC with a reversed phase column (C18) and a UV spectrophotometry detection. Then, from the time-concentration curves we have evaluated the T > MIC for an enterobacteria (MIC = 8 micrograms/mL) and for Pseudomonas (MIC = 16 micrograms/mL). Concerning intermittent administration T > MIC were 74% (c > MICenterobacteria) and 62% (c > MICPseudomonas). These percentages in the continuous arm were 100% (c > MICenterobacteria) and 99% (c > MICPseudomonas). Tazobactam concentrations were low and even undetectable between each injection in the intermittent administration arm. This was not found within the continuous administration arm. In conclusion, for the intermittent administration, we observed some long periods occurring before each injection while antibiotic concentrations were under the MIC of most bacteria. During these same periods tazobactam concentrations were under the efficacy threshold. These periods were not observed within the continuous administration arm.
We report the case of a patient who experienced a postoperative Wernicke encephalopathy 8 days after a left hepatectomy performed for metastasis related to a rectal cancer. During the six months before surgery the patient lost 10 kg of weight (15%). Moreover, in the postoperative period the patient received exclusively 5% dextrose solution intravenously. On the 8th postoperative day, an alteration of consciousness, a vertical nystagmus and an ataxia led to consider the diagnosis of thiamine deficiency that was then established by the decrease in the transcetolase activity of the red blood cells. Vitamin B1 supply improved the clinical status rapidly and completely. This observation allows to review aetiologies and clinical forms of thiamine shortage. In addition, it stresses the detection of exposed patients and the prevention methods.
In a retrospective study, 2,238 mycologic samples obtained in 1999 from 89 patients hospitalised in an intensive care unit dedicated to digestive diseases were analysed. Feasibility of monitoring fungal colonisation and implications for workload and costs were assessed. From this experience, we confirmed the ability of the Pittet index to identify patients at high risk for Candida infection. Monitoring of Pittet index required a high degree of cooperation between the intensive care unit and the laboratory of mycology, and a precise definition of the modalities of sampling. It entailed a significant increase in costs and workload. A treatment was started whenever a colonisation index > or = 0.5 was associated with severe clinical or biological signs. This involved an increase of the expense of antifungal drugs. The potential benefits could not be evaluated from our study. Direct observation of pseudomycelium in the samples and candiduria were significantly correlated to fungal colonisation.
Orthotopic liver transplantation is now a successful treatment for end-stage liver diseases. Since most components of the coagulation system are synthesized by liver parenchymal cells, there is always a risk of genetic defects of hemostasis being transmitting by liver transplantation. Some coagulation factor defects, such as protein C deficiency, do not induce abnormalities in routine coagulation tests and, thus, go undetected before organ procurement. We report the first case, to our knowledge, of the transmission of heterozygous protein C deficiency, an autosomal recessive genetic defect, associated with dysfibrinogenemia, an autosomal dominant trait, by liver transplantation. Both the recipient and the donor presented with severe thrombotic complications. This case shows that potentially morbid genetic defects can be transmitted by organ transplantation, and it emphasizes the difficulty associated with organ procurement criteria, particularly for liver transplantation, in which routine blood tests appear insufficient for determining whether or not organs can or should be procured from a given donor.
An MR study performed on a patient who presented a tetraplegia after liver transplantation, revealed bilateral hypersignal of internal globus pallidus on T2 weighted images. Diagnosis of extrapontine myelinolysis was proposed based on clinical presentation and lesions topography, although absence of natremic disorders. Confirmation of diagnosis was obtained on an MR study performed a month later, which demonstrated a pontine extension. Extrapontine myelinolysis can precede pontine involvement. Diagnosis of myelinolysis should be evoked although MR normal appearance of the pons.
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The pharmacokinetics of piperacillin and vancomycin used intravenously as antibioprophylaxis were measured in the plasma and bile during orthotopic liver transplantation. Piperacillin (4 g and then 2 g every 4 h) and vancomycin (1 g and then 0.5 g every 6 h) were infused in 10 patients. During vascular clamping without venovenous bypass, clearance of both antibiotics decreased in relation to renal insufficiency. During the surgical procedure, volume of distribution of both drugs increased because of fluid redistribution. The peaks of piperacillin after first, second and third administrations were respectively 314, 265 and 210 mg.l-1, while trough levels were 46.5, 55.2 and 54.5 mg.l-1. The peaks of vancomycin were 54.4, 49.6 and 40.9 mg.l-1, while first and second trough levels were 9.5 and 12 mg.l-1. These plasma concentrations were quite similar to levels reported in healthy subjects despite large blood loss and fluid replacement. However, piperacillin trough concentrations (< 64 mg/l) were too low in relation to its concentration-dependent antibacterial activity and vancomycin peak concentrations (> or = 40 mg/l) were slightly too high in relation to its toxicity.
Two cases of central pontine myelinolysis (CPM) following orthotopic liver transplantation (OLT) are reported. Several months after the onset of this neurological syndrome, the two patients are still alive but with severe neurological sequelae. Some patients undergoing emergency OLT present a high risk of CPM because of pre-existing malnutrition, encephalopathy, and hepatic insufficiency. All of these are associated with an inevitable abrupt rise in sodium serum concentration due to intraoperative compensation of blood losses with high-sodium content blood products. Whenever the renal capacity to excrete sodium is impaired by the surgical procedure, continuous intraoperative venovenous hemofiltration is recommended.
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In order to design a new, performed tracheal tube adapted to the shape of the upper respiratory tract, we have undertaken an anthropometric study from lateral x-rays of the neck in 130 patients with the head in a fixed position. In order to assess different clinical situations, we studied three groups of patients: group 1 = sitting, no tracheal tube; group 2 = supine, no tracheal tube; group 3 = supine, trachea intubated. We defined a standard coordinate system and determined mathematical curves for segments of the upper respiratory tract by a polynomial regression method. With these data it was possible to study the effects of physiological variations on the shape of the curves. It was then possible to determine at which region changes occur and the factors influencing these changes. We found that the relative position of the larynx was constant, whereas the hypopharynx exhibited the greatest change with the position of the head. These observations should allow us to construct a new, performed tracheal tube with elastic compliance properties to fit the changes occurring in the region of the hypopharynx.
We report two cases of central pontine myelinolysis (CPM) following liver transplantation. The incidence may well be underestimated as in the past the diagnosis of CPM was based on postmortem findings. Malnutrition, poor clinical condition, encephalopathy are common features of transplanted patients developing CPM. The clinical course is characterized by a biphasic pattern; after normal recovery from anesthesia, there is a subsequent and gradual deterioration in the neurological state. The complex syndrome associates loss of consciousness, flaccid quadriplegia and pseudobulbar palsy. Among the many factors suspected of inducing CPM, a rapid correction of natremia (> 12 mmole/l/day) seems most probable. With regards to liver transplantation, CPM presents rather specific problems. Delaying transplantation to correct hyponatremia carries a risk of severe hepatic encephalopathy. On the other hand, the intraoperative compensation of blood losses with high sodium content blood products tends to induce an abrupt rise in sodium serum concentration. Moreover, renal capacity to excrete sodium is often impaired, due to hepatic insufficiency and surgical procedure. Transplantation should not be delayed, but as infusion of large amounts of sodium cannot be avoided (fresh frozen plasma, human albumin, red blood cells), natremia may be controlled by continuous veno-venous hemofiltration with low sodium content substitution fluids.
The factors involved in reducing consumption of bank packed red cells (PRC) were studied over three one year periods (1983, 1987 and 1989) in a Department of Vascular and General Surgery. The effects of autologous blood salvage (started in 1987), associated with the management of homologous blood by a branch of the blood bank inside the operating theater suite were assessed. In 1989, intentional normovolaemic haemodilution became virtually systematic, on top of the intraoperative blood salvage, for all patients due to undergo surgery with a risk of severe blood loss. The number of surgical procedures carried out during those three years did not vary. However, in the same time, the annual consumption of homologous PRC decreased by an overall 56% (36.7% between 1983 and 1987, and 29.8% between 1987 and 1989). This decrease was mostly due to a fall in prescription in the operating theaters, and not in the wards. In the same time, albumin consumption increased sixfold. Such transfusional policies can only be carried out if there is good cooperation between the blood bank and the prescribers of blood products.
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An open and prospective phase II trial assessing the action of a fixed dose of a low molecular weight heparin (enoxaparin), determined by the patient's weight, in the treatment of established deep vein thrombosis of the leg is hereby described. A series of 51 patients received a regimen of 1 mg.kg-1 or 105 anti-Xa IU.kg-1 s.c. every 12 h for a period of 12 days. Thromboses were categorized as postsurgical (28 cases) or medical (23 cases). There was a significant improvement in clinical signs (pain and edema) and phlebographic indices (Marder and Arnesen scores). The extent of vascular clearing was a 30% reduction in phlebographic scores between day 0 and day 12. Only 5 patients had an absence of improvement. Two of the 51 patients stopped the drug in the first week of treatment because of bleeding. There were no occurrences of thrombocytopenia, and the agent was well tolerated.
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Unfractionated heparin is effective in the treatment of deep venous thrombosis and pulmonary embolism but may lead to significant side-effects (bleeding complications and thrombocytopenia). Low molecular weight heparin fragments have been shown to be as effective as unfractionated heparins during prophylaxis with a once-daily injection regimen. The aim of this open study was to assess the tolerance and the efficacy of enoxaparin in established venous thromboembolism. The study included 36 consecutive patients (mean age 60 years) (range 13-87) with recent deep vein thrombosis (less than 5 days) documented by venography. All patients received enoxaparin twice daily at a fixed dosage of 2 mg/kg/day. The efficacy was assessed by the evolution of Arnesen venographic score. Seventeen patients showed a moderate improvement (less than 35%) and 17 patients had a marked improvement (over 35%). Two patients were not evaluated for efficacy because they displayed bleeding complications. No relationship was found between anti-Factor Xa level and regression of venographic score. In conclusion, subcutaneous administration of enoxaparin proved to be an effective antithrombotic therapy. A fixed dosage of 2 mg/kg/24 h should be the basis of the randomized controlled study ongoing at the present time.