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Biomedical subjects

A Steib

Publications and source records attributed to A Steib.

At least 19 recordsLinked to original sources
PubMed1996

[Use of urapidil during surgery for pheochromocytoma].

OBJECTIVE: To investigate the efficacy of urapidil, administered either by boluses or a continuous infusion, to control hypertension during resection of phaeochromocytoma. STUDY DESIGN: Prospective open study. PATIENTS: Seven consecutive patients aged between 23 and 60 years, with a hypersecretant phaeochromocytoma. METHODS: Standard anaesthetic technique including thiopentone, opioid, muscle relaxant, nitrous oxide and isoflurane. Invasive haemodynamic monitoring with a Swan-Ganz catheter and radial arterial catheterization. Infusion of cristalloids and colloids (20 mL.kg-1.h-1). Evaluation of two regimens of urapidil administration following the initial injection of a bolus of 25 mg in case of severe hypertension i.e. SAP > 180 mmHg > 1 min: a) boluses of 25 or 50 mg of urapidil injected according to the response obtained after the first bolus or in case of resurgence of a new hypertensive event; b) continuous infusion of 150-200 mg.h-1. RESULTS: Three patients developed hypertension between the induction of anaesthesia and the beginning of the tumor dissection. One bolus of 25 or 50 mg of urapidil was efficient to control this event. During the dissection of the phaechromocytoma, higher doses (75-100 mg) were required to significantly decrease SAP and DAP values (P < 0.001). Heart rate did not change significantly in patients not receiving esmolol. A continuous infusion, used in three patients, did not prevent the occurrence of peaks in two patients, requiring additional doses. After the removal of the tumor, three patients experienced severe hypotension with decreased systemic vascular resistances and high cardiac output. Vasoactive drugs were injected to restore better haemodynamic conditions. CONCLUSION: Urapidil is useful for the management of hypertension during the resection of phaechromocytoma. However further investigations are needed to determine its role in the occurrence of prolonged collapse after the tumor removal.

Adrenal Gland Neoplasms↗
PubMed1996

[Anesthesia and implantable automatic defibrillator].

Since the introduction of first generation automatic implantable cardioverter defibrillators (AICD) in 1980, an increasing number of such devices have been inserted in patients at high risk for sudden death by ventricular tachycardia or fibrillation (VT/VF). With the improvement of technology and implanting techniques, devices may be inserted at present subcutaneously into the abdominal or the thoracic wall, rather than by thoracotomy. The anaesthesist is involved in the primary implantation of the AICD and the secondary testing of efficiency. Implantation generally requires general anaesthesia and the extension of monitoring is guided by the patient's underlying disease(s). The efficiency of the implanted system is tested one to two months later in inducing VT/VF under general anaesthesia and in determining the defibrillation threshold. The anaesthetist may also have to take care of patients with a AICD. For such cases the following recommendations can be made: a) gloves should be worn by doctors and nurses coming into contact with these patients, in order to limit the risk of electrification; b) a ring magnet must be available to inactivate the unit; c) in case of external defibrillation, the external paddles should be oriented perpendicularly to the line joining the two implanted electrodes; d) AICD should be disabled during electrocautery and prior to electroconvulsive therapy; e) the assistance of a electrophysiologist may be helpful for the management of these patients.

Anesthesia↗
PubMed1995

Auxiliary liver transplantation for fulminant and subfulminant hepatic failure.

We report the first series of 9 auxiliary liver transplantations performed as a bridge to recovery in 8 patients with fulminant and subfulminant hepatic failure. Hepatic failure was due to hepatitis A virus (n = 3), hepatitis B virus (n = 1), hepatotoxic drugs (n = 2), autoimmune disease (n = 1), or it was of unknown origin (n = 1). The donor liver was reduced to a left lobe (n = 2), a left liver (n = 4), or a right liver (n = 3), and was implanted in an orthotopic position beside the native liver after it was resected by a left or a right hepatectomy. Conventional immunosuppression was used to prevent rejection. Six patients regained normal consciousness within 2 weeks, without any sequelae. Two patients had persisting encephalopathy due to graft initial dysfunction, one of whom showed portal vein thrombosis, which was successfully cleared. The other one showed hepatic vein stenosis and was retransplanted at day 15. Five of eight patients had to be reoperated because of a surgical complication. Five patients showed rapid regeneration of their native liver, but one died at day 45 from severe herpes virus broncholitis. The auxiliary grafts were removed (n = 3) or left to atrophy by tapering immunosuppression (n = 1). One patient developed cirrhosis of the native liver and died of infectious complications at day 42. The native livers of the two remaining patients are still atrophic, one at 4 months and one at 1 month posttransplant. Finally, 6 of 8 patients are alive with a follow-up of 1 to 17 months. Four of them have permanently stopped their immunosuppressive therapy. Our experience demonstrates that auxiliary orthotopic liver transplantation (1) is feasible in children and adults, using either a left or a right liver graft, (2) is efficient in providing adequate liver function, and (3) gives a real chance to the native liver to regenerate, offering these patients a future free of immunosuppression.

Adolescent↗
PubMed1994

[Diprivan: drug interactions].

Concerning the pharmacokinetic or pharmacodynamic interactions, the following is recommended: Use smaller doses of alfentanil when the latter is combined with propofol, because of a higher risk of ventilatory depression. Decrease doses of each agent whenever propofol is combined with thiopentone or midazolam to induce anaesthesia. The prophylactic or therapeutic use of atropine is indicated when propofol is associated with agents reducing heart rate. Prefer propofol to induce anaesthesia for eye surgery, if suxamethonium is required. In the absence of sufficient data, propofol should be administered with care in patients taking cardiovascular medication (risk of hypotension) or cyclosporine (enhanced toxicity).

Anesthesia, Intravenous↗
PubMed1994

[Anesthesia for MRI examination].

Magnetic resonance imaging (MRI) requires the patients to stay for 30-45 min in a magnetic closed noisy space. Therefore most children and agitated adults require general anaesthesia or sedation in order to high quality images. Anaesthesia may be given by several routes (TIVA, inhalational or intrarectal administration) using common drugs. However, the magnetic field limits the selection of patients undergoing MRI and the spectrum of anaesthetic and monitoring equipment. The magnetic field may have deleterious effects on implanted ferromagnetic devices. It may attract objects towards the magnet centre at a dangerous speed. Moreover it may disturb the function of monitors and anaesthesia machines which should be tested for a specific magnetic field strength before introducing their use in a given MRI unit.

Adolescent↗
PubMed1994

Predictive factors of hyperfibrinolytic activity during liver transplantation in cirrhotic patients.

Hyperfibrinolytic activity occurs frequently during liver transplantation in cirrhotic patients. In order to identify those patients at high risk for increased intraoperative blood loss before operation, we determined predictive indicators of hyperfibrinolysis. We studied 56 cirrhotic patients undergoing liver transplantation with the same anaesthetic procedure and transfusion regimen. The preoperative coagulation patterns of the 11 patients who experienced acute intraoperative hyperfibrinolytic activity were compared with those of the 45 patients who did not suffer this complication. Before surgery, patients with intraoperative hyperfibrinolysis had decreased prothrombin time (PT) and euglobulin lysis time (ELT), and increased thrombin time (TT) and fibrinogen degradation products (FDP), whereas alpha angle and maximum amplitude (MA) were reduced on thrombelastography. Stepwise multivariate analysis disclosed three components which were significantly linked with occurrence of hyperfibrinolysis: TT, FDP and MA. Their sensitivity, specificity, positive and negative predictive values demonstrated that patients with FDP > or = 48 mg litre-1 and MA < or = 35 mm before incision had 100% probability of developing hyperfibrinolytic activity during transplantation.

Adult↗
PubMed1993

[Monitoring of hemostasis during liver transplantation: contribution of thromboelastography].

Monitoring of coagulation is mandatory during liver transplantation (LT). Standard coagulation tests may be routinely used. However, they give static information and may be inadequate in case of severe coagulation defect. Interest has been recently focused on thromboelastography (TEG) which could give more suitable and rapid information in these cases. Few studies have evaluated the clinical interest of TEG compared to conventional tests. This comparison was the aim of the present study, performed in 89 patients scheduled for LT. The anaesthetic management as well as procedure of transfusion were similar in all patients. Before unclamping, 5000 KIU.kg-1 of aprotinin were injected. Routine tests and TEG were performed at the beginning and end of both pre-anhepatic and anhepatic phases, and 5, 30, 60, and 120 min after the revascularisation of the new liver. A phase of hypocoagulability was observed after unclamping. Biological signs included an increase in activated thromboplastin time, a reduction of alpha angle and maximum amplitude on TEG with a lengthening of its r + k component. A strong correlation existed between maximum amplitude and platelets, maximum amplitude and fibrinogen, alpha and fibrinogen at each time of the surgical procedure. Euglobulin lysis time decreased significantly after clamping, whereas fibrin degradation products increased at the same time. However, typical fibrinolysis with a clot lysis index (CLI) below 55% was only observed in 15 patients. Twelve of them had a CLI value reaching 0%, associated with severe generalized oozing. Aprotinin (200,000 to 600,000 KIU) corrected these abnormalities. These results show that TEG may not be very helpful to determine whether platelets or fibrinogen are involved in the phase of hypocoagulability detected after unclamping.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Anesthesia for non-specific surgery in a post-transplantation patient].

The increase of non specific surgeries in transplanted patients may be related to the better survival achieved by the efficacy of immunosuppressive therapy and improved surgical and intensive care conditions. Therefore, the anaesthetist may be mandated to give anaesthesia in such patients, treated in hospitals which are not involved in transplantation procedures. The ignorance of the main physiologic and pharmacological changes in the new grafted organ as well as the knowledge of high risks of rejection or infection contribute to the anxiety often encountered in front of these patients. The denervated heart is unable to respond to stimulations requiring the integrity of autonomic neural mechanisms. Modulation of cardiac output depends on intrinsic activity (Frank-Starling mechanism) and therefore of end diastolic volume (preload). The denervated transplanted lung shows inability to elicit cough reflex; the latter is totally abolished in case of tracheal anastomosis. These physiologic changes have no deleterious effects on early cardiac and pulmonary functions following transplantation. In the same way, renal, liver or pancreatic functions are restored after respective replacement. However chronic rejection occurs frequently in 50% of patients in a mean time of 5 years following surgery except for liver transplanted patients which seem to be better protected. It results in a progressive decrease in organ function tests. The preoperative assessment requires primary contact with the transplant center. This communication should give precious information about the last biological and functional results as well as about the immunosuppressive therapy. Standard preoperative investigations include measurements of haemoglobin, urea, electrolyte and creatinine concentrations, liver tests, ECG, chest X-ray and coagulation pattern. Previsible difficult intubation should be detected in case of previous pancreas transplantation. Immunosuppressive therapy and other treatments should not be disrupted until surgery. Usual premedication may be used. Previsional peroperative transfusion requires specific packed red blood cells, fresh frozen plasma and platelets in order to reduce CMV contamination and GVH reactions. Locoregional or general anaesthesia may be used with respect to usual contraindications. Special attention should be given in cardiac transplanted patients in order to maintain adequate preload. As atropine is ineffective, bradycardia may be treated by isoprenaline. Patients with lung transplants require a reduction of vascular loading and of hydratation and early postoperative pulmonary physiotherapy. Pancreas transplanted patients often suffer from severe cardiac diseases (coronaropathy). The immunosuppressive therapy modifies the pharmacological behavior of many anaesthetic agents. Ciclosporine enhances mainly the effects of muscle relaxants. Peroperative invasive monitoring requires full aseptic techniques. Invasive monitoring should be discussed in terms of benefit-risk ratio.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesia↗
PubMed1993

Oesophageal thermal tube for intraoperative hypothermia in liver transplantation.

In order to prevent the occurrence of major hypothermia during liver transplantation, with its deleterious effects on intraoperative cardiovascular activity and on postoperative graft functioning, this study evaluated the benefit of an oesophageal rewarmer, used during surgery, in addition to the usual methods of warming (OR temperature at 22 degrees C, rewarming of fluids and blood, heating mattress, heat and moisture exchanger). We compared 10 patients with an oesophageal rewarmer (OeR group) to 10 patients without (Control group). The anaesthetic procedure was similar in all cases. Rectal (RT) and pulmonary artery (PT) temperatures were recorded during the three phases of surgery (pre-anhepatic, anhepatic, postanhepatic phase) and their time course was analysed with non-parametric tests. The two groups were comparable with regard to duration of surgery, blood and fluid requirements and veno-venous bypass flow rate. The RT decreased similarly in both groups, but was significantly higher in the OeR group at peritoneum closure (P < 0.01). The PT was higher in the OeR group after onset of venous shunting (P < 0.05) and during the third phase of surgery (P < 0.01). Three incidents (one leakage and two herniations of the latex tube) occurred, without detrimental effects on the patients. It is concluded that the oesophageal heat exchanger allows better rewarming after revascularization of the graft, but is unable to prevent cardiac hypothermia at unclamping.

Adult↗
PubMed1993

Concentrations in plasma and tissue penetration of ceftriaxone and ornidazole during liver transplantation.

Plasma and epiploic fat drug concentrations and fat penetration of ceftriaxone and ornidazole given for antimicrobial prophylaxis were studied in 11 patients scheduled for liver transplantation. Ceftriaxone (1 g) and ornidazole (500 mg) were infused during 30 min after the induction of anesthesia. Arterial blood and epiploic fat samples were collected at 30, 60, and 120 min and then every 90 min following the end of the infusion until closure of the peritoneum. Blood samples were immediately centrifuged, and plasma and fat were stored at -35 degrees C until analysis. Ceftriaxone and ornidazole concentrations were determined by high-performance liquid chromatography. Surgery lasted 440 +/- 84 min and required a mean of 9.5 units of packed erythrocytes and 13 units of fresh frozen plasma. Plasma ceftriaxone concentrations decreased from 89 +/- 34 to 41 +/- 16.5 micrograms/ml from the beginning of the operation until the time of closure of the peritoneum. Corresponding levels in epiploic fat decreased from 8.7 +/- 3.3 to 4.5 +/- 3.5 micrograms/g. Ornidazole concentrations ranged, respectively, between 8.7 +/- 2.5 and 4.9 +/- 1.7 micrograms/ml in plasma samples and 4.6 +/- 1.2 and 2.5 +/- 1.1. micrograms/g in fat samples. Rates of penetration into the omentum remained at about 9% for ceftriaxone and between 50 and 70% for ornidazole. Tissue ceftriaxone concentrations were, in all cases, greater than typical MICs for 90% for Escherichia coli and Klebsiella isolates tested (MIC90S). They were insufficient in 40% of patients after 60 min with regard to the MIC90S for Staphylococcus aureus. Tissue ornidazole concentrations were not superior to MIC90S for anaerobes after 30 min in 50% of patients. These results show that a single dose of 1 g of ceftriaxone provides adequate coverage against gram-negative bacteria and that 1 g instead of 500 mg ornidazole may provide a protective effect against anaerobes during liver transplantation. Prophylaxis against S. aureus and Streptococcus faecalis requires more specific antibiotics. Prophylaxis for patients with significant blood loss or initial severe renal or hepatic failure needs further evaluation.

Adipose Tissue↗
PubMed1993

Mixed venous oxygen saturation monitoring during liver transplantation.

High mixed venous oxygen saturation (SVO2) values due to limited oxygen extraction capacities are reported in some patients with severe liver disease. The aim of this study was to evaluate the usefulness of SVO2 monitoring to assess adequate oxygen supply in such patients scheduled for liver transplantation. Nineteen patients with oxygen extraction ratio below 12% were analysed and compared to 20 patients with a pre-operative ratio over 17%. The two groups were comparable with regard to initial pathology, preload and haemoglobin levels. SVO2 values measured discontinuously by co-oximetry were unaffected by the first part of surgery and the clamping period in patients with low oxygen extraction ratio. In these patients, SVO2 was never correlated to oxygen supply during the whole procedure whereas good correlation was noted before and after unclamping in the other group. Tissue hypoxia detected by a dependent oxygen consumption-oxygen supply relationship occurred at clamping and unclamping in patients with initial low oxygen extraction capacities. It is concluded that expensive SVO2 continuous monitoring may not be effective in reflecting changes in oxygen supply in anaesthetized patients with initial severely impaired oxygen extraction capacity.

Adult↗
PubMed1992

[Difficult intubation managed by laryngeal mask and fibroscopy].

A case is reported of a patient due to undergo a combined kidney and pancreas transplant who proved to be difficult to intubate. This diabetic hypertensive 35-year-old male patient also had ankylosing spondylitis. Mouth opening was normal (more than fingers' breadth), the chin-sternum distance was 4 cm on full cervical flexion, and cervical extension was only slightly impaired. The Mallampati score was 1. Anaesthesia was induced with thiopentone, fentanyl and 6 mg of pancuronium. Mask ventilation was quite satisfactory. However, on laryngoscopy, the vocal cords could not be seen. Several attempts to carry out endotracheal intubation, including with a stylet, failed. A laryngeal mask (LM) was therefore applied to ventilate the patient correctly. It was not possible to pass a small endotracheal tube (6 mm diameter) through the LM tube, probably because of a small malposition of this latter. A paediatric fibroscope, passed through the LM tube, served as guide for the endotracheal tube. The mask was not removed, although its cushion was slightly deflated, so as not to extubate the patient. The benefits and usefulness of a laryngeal mask in predictable and unpredictable cases of difficult intubation are discussed.

Adult↗
PubMed1992

Tissue oxygenation during liver transplantation.

OBJECTIVES: a) To assess perioperative changes in tissue oxygenation parameters during liver transplantation; b) to evaluate the need for venovenous bypass as hemodynamic support; and c) to assess the efficacy of mixed venous oxygen saturation monitoring and the importance of lactate determinations in the management of patients following liver transplantation. DESIGN: Prospective case series. SETTING: Liver transplant unit in a university hospital. PATIENTS: A total of 68 consecutive patients undergoing liver transplantation. The entire population was analyzed before and after transplantation, dividing the patients into two groups, based on whether their initial cardiac index was higher (n = 37) or lower (n = 31) than 4.5 L/min/m2. MEASUREMENTS: Hemodynamic measurements and blood gas analyses were made before incision, before vascular clamping (including hepatic artery, portal vein and inferior vena cava), during the anhepatic phase, and at 5, 30, 60, and 120 mins following unclamping. Oxygen transport and oxygen consumption values were calculated. Serum lactate concentrations were measured by enzymatic technique. MAIN RESULTS: Mixed venous oxygen saturation was correlated with oxygen transport (Do2) in the whole population in which an abnormal oxygen consumption (Vo2)-Do2-dependent relationship occurred from the beginning of operation until 30 mins following unclamping. The comparison between hyperdynamic patients (initial cardiac index greater than 4.5 L/min/m2) with impaired tissue oxygenation and normodynamic patients showed that mixed venous oxygen saturation failed to correlate with Do2 when the cardiac index was greater than 4.5 L/min/m2 and that the Vo2-Do2 dependency was only noted in these patients. The serum lactate concentrations were similar in both groups. CONCLUSIONS: The Vo2-Do2-dependent relationship and mixed venous oxygen saturation-Do2 correlation noted in the 68 studied patients suggest the need for venovenous bypass and the reliability of mixed venous oxygen saturation monitoring in all patients scheduled for liver transplantation. However, a sharper comparison between hyperdynamic and normodynamic patients demonstrated the lack of efficacy of mixed venous oxygen saturation monitoring in predicting adequate tissue oxygenation in the first group and the mandatory need for venous shunting to limit tissue hypoxia which occurred despite its use only in these patients. Lactic acidosis appeared similarly in both groups and could not be linked to tissue hypoxia.

Acidosis↗
PubMed1992

[The laryngeal mask].

The laryngeal mask (LM) is a new concept developed by Brain. Easily inserted, the LM allows appropriate ventilation without the disadvantages of either the facial mask or the endotracheal intubation with its own complications. The limits of its use concern all the cases of reduction of thoracopulmonary compliance and full stomach. The LM offers no protection against regurgitation and aspiration. Airway obstruction may occur following laryngospasm (light anaesthesia) or down folding of the epiglottis. Trauma to the uvula and the posterior pharyngeal wall have been reported. The LM may be useful in all cases of surgery in which intubation is not absolutely required. Moreover, the LM is widely used for ENT and ophthalmic surgeries, in paediatric and adult procedures. Many cases of foreseeable or unforeseeable difficult intubation have been resolved by the insertion of a LM, allowing secondary intubation through the mask. Further investigations are required in order to evaluate the real limits and indications for its extended use.

Anesthesiology↗