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Biomedical subjects

Kamran Samii

Publications and source records attributed to Kamran Samii.

17 recordsLinked to original sources
PubMed2006

Influence of renal function on trough serum concentrations of piperacillin in intensive care unit patients.

OBJECTIVE: To explore the effects of renal function estimated by measured creatinine clearance (Cl(CR)) on trough serum concentration (C(min)) of piperacillin given to critically ill patients. DESIGN: Prospective observational study. SETTING: An intensive care unit and research ward in a university hospital. PATIENTS: Seventy critically ill patients, including 22 with severe trauma. INTERVENTIONS: All subjects received an intravenous infusion of piperacillin 4 g three times (n = 61) or four times (n = 9) per day. Piperacillin C(min) values were determined 24 h after treatment started and compared to the French breakpoint defining antibiotic susceptibility against Enterobacteriaceae (8 mg/l) or Pseudomonas sp. (16 mg/l). RESULTS: Median (range) piperacillin C(min) was 11.9 (< 1-156.3) mg/l, with a great variability among patients. Although the median value was close to the breakpoints, sub-therapeutic plasma levels were frequently observed. Piperacillin C(min) was lower than the breakpoint for Enterobacteriaceae in 37% of patients, and lower than the breakpoint for P. aeruginosa in 67% of them. A strong relationship was observed between piperacillin C(min) and Cl(CR): the higher the Cl(CR,) the lower the piperacillin C(min )in serum. For patients with a Cl(CR) < 50 ml/min, enough piperacillin C(min) was achieved in most patients with 12 g piperacillin per day. For patients with higher Cl(CR) values, a piperacillin daily dose of 16 g or more may be warranted. CONCLUSIONS: In critically ill patients, therapeutic monitoring must be part of the routine, and knowledge of Cl(CR) value may be useful for the choice of adequate initial piperacillin dosing.

Adolescent↗
PubMed2006

Clinical profile, contemporary management and one-year mortality in patients with severe acute heart failure syndromes: The EFICA study.

BACKGROUND: Little is known about the epidemiology of acute decompensated heart failure (ADHF) in patients admitted to intensive and coronary care units (ICU/CCU). Observational data may improve disease management and guide the design of clinical trials. AIMS: EFICA is an observational study of the clinical profile, management and survival of ADHF patients admitted to ICU/CCU. METHODS: The study included 599 patients admitted to 60 ICU/CCUs across France. Relevant data was recorded during hospitalisation. Survival was assessed at 4 weeks and 1 year. RESULTS: The main cause of ADHF was ischaemic heart disease (61%); 29% of patients had cardiogenic shock. Mortality was 27.4% at 4 weeks and 46.5% at 1 year, increasing to 43.2% and 62.5%, respectively, when including pre-admission deaths. Shock patients had the highest [57.8% vs. 15.2% without shock (p < 0.001)] and patients with hypertension and pulmonary oedema had the lowest 4-week mortality: (7%). Pre-admission NYHA class III-IV heart failure, not initial clinical presentation, influenced 1-year mortality. CONCLUSION: ADHF is a heterogeneous syndrome. Based on initial clinical presentation, three entities with distinct features and outcome may be described: cardiogenic shock, pulmonary oedema with hypertension, and 'decompensated' chronic heart failure. This should be taken into account in future observational studies, guidelines and clinical trials.

Aged↗
PubMed2006

[Epidural hematoma after hemorrhagic shock in a parturient].

PURPOSE: Epidural hematoma is a rare but serious complication of epidural anesthesia. We report a case of epidural hematoma, occurring in an obstetric patient after the epidural catheter had been withdrawn accidentally after an episode of hemorrhagic shock leading to a hypocoagulable state. CLINICAL FEATURES: A patient had the epidural catheter inserted during labour when coagulation was normal. She had a postpartum hemorrhage with alteration of coagulation (platelets 16 x 10(-9) x L(-1), thrombin time: 85 sec. Vital signs returned to normal after a general anesthetic, transfusion of blood products, volume repletion and ligation of hypogastric arteries. It was then noticed that the epidural catheter had been withdrawn inadvertently while the patient was hypocoagulable. The patient then developed neurological signs consistent with spinal cord compression due to an epidural hematoma. A hematoma extending from T3 to L5 was diagnosed by magnetic resonance imaging. Because the cord had minimal compression, no specific action was undertaken, other than clinical and radiological follow-up. There were no long-term sequelae. CONCLUSION: In the presence of an epidural hematoma, surgery for emergency cord decompression is usually required. Another option that receives increasing attention is to monitor neurological function, but the indications for this expectant treatment are not well defined.

Adult↗
PubMed2006

Spinal anesthesia using single injection small-dose bupivacaine versus continuous catheter injection techniques for surgical repair of hip fracture in elderly patients.

Aging and disease may make elderly patients particularly susceptible to hypotension during spinal anesthesia. We compared the hemodynamic effect of continuous spinal anesthesia (CSA) and small dose single injection spinal anesthesia (SA) regarding the incidence of hypotension. Seventy-four patients aged >75 yr undergoing surgical repair of hip fracture were randomized into 2 groups of 37 patients each. Group CSA received a continuous spinal anesthetic with a titration of 2.5 mg boluses every 15 min of isobaric bupivacaine, while group SA received a single injection spinal anesthetic with 7.5 mg of isobaric bupivacaine. The overall variations in noninvasive automated arterial blood pressure were not statistically significantly different in the 2 groups at baseline and after CSA or SA (not significant). In the SA group, 68% of patients experienced at least one episode of hypotension (decrease in systolic arterial blood pressure greater than 20% of baseline value) versus 31% of patients in the CSA group (P = 0.005). In the SA group, 51% of patients experienced at least one episode of severe hypotension (decrease in systolic arterial blood pressure more than 30% of baseline value) versus 8% of patients in the CSA group (P < 0.0001). In the CSA group, 4.5 +/- 2 mg of ephedrine was injected versus 11 +/- 2 mg in the SA group (P = 0.005). In the CSA group, 5 mg (2.5-10) of anesthetic solution was required versus 7.5 mg in the SA group (P < 0.0001). We conclude that, in elderly patients undergoing hip fracture repair, CSA provides fewer episodes of hypotension and severe hypotension compared with a single intrathecal injection of 7.5 mg bupivacaine.

Aged↗
PubMed2005

Stroke output variations calculated by esophageal Doppler is a reliable predictor of fluid response.

OBJECTIVE: Esophageal Doppler allows continuous monitoring of stroke volume index (SVI) and corrected flow time (FTc). We hypothesized that variations in stroke output index SOI (SVI/FTc) during volume expansion can predict the hemodynamic response to subsequent fluid loading better than the static values. DESIGN AND SETTING: Prospective study in the intensive care unit of a university hospital. PATIENTS: Fifty-one patients with circulatory failure were monitored by esophageal Doppler. INTERVENTIONS: Patients who responded to a first fluid challenge received a second one. Patients who responded to both were classified as responders-responders, and those who did not respond to the second as responders-nonresponders. In these two groups we compared DeltaSVI, DeltaFTc, and DeltaSOI during each fluid challenge and also static values at the end of each fluid challenge. MEASUREMENTS AND RESULTS: After the first fluid challenge DeltaSOI and DeltaSVI were significantly higher in patients who responded to subsequent volume expansion than in patients who no longer responded. ROC curves showed that DeltaSOI was a better predictor of fluid responsiveness than DeltaSVI. During volume expansion a DeltaSOI value of 11% discriminated between responders and nonresponders to subsequent volume expansion with a sensitivity of 91% and a specificity of 97%. There was no significant difference between the two groups for FTc value at the end of first fluid challenge. CONCLUSIONS: Analysis of DeltaSOI during fluid challenge predicts response to subsequent fluid challenge and FTc is not a reliable indicator of cardiac preload.

Adult↗
PubMed2005

[Neurostimulation does not increase the success rate of saphenous nerve blocks].

PURPOSE: To evaluate neurostimulation of motor components of the vastus medialis muscle and the rectus femoris muscle, with a view to blocking the medial sensory fibres of the saphenous nerve. METHOD: First we dissected four femoral trigones, in order to select our puncture point. We were able to observe that, at the flexion crease of the thigh, the different fibers that make up the femoral nerve were clustered together and the saphenous nerve and the vastus medialis nerve had not yet separated from the femoral stem. Secondly, we conducted a prospective clinical study among 71 patients who had undergone surgery on the lower third of the leg with a sciatic block and a saphenous nerve block. The saphenous nerve block was performed using 10 mL of local anesthetic, by puncturing the flexion crease of the thigh in a bid to obtain one of two muscle responses: medial (contraction of the vastus medialis muscle) or anterior (contraction of the rectus femoris muscle and elevation of the patella). RESULTS: There was an overall success rate of 80% with the saphenous nerve block, with no statistical difference existing between the two response types. Average duration for the block to be completed was two minutes and it took an average of 15 min before the anesthesia took effect. No complications were encountered, apart from a puncture of the femoral artery, which was clinically inconsequential. CONCLUSION: Neurostimulation of the vastus medialis muscle has the same effect as neurostimulation of the rectus femoris muscle with respect to anesthesia of the saphenous nerve. Neurostimulation of the medial compartment of the femoral nerve saves local anesthetic, compared to a standard femoral block.

Electric Stimulation↗
PubMed2005

A modified coracoid approach to infraclavicular brachial plexus blocks using a double-stimulation technique in 300 patients.

Infraclavicular brachial plexus block is used less than other techniques of regional anesthesia for upper-limb surgery. We describe a modified coracoid approach to the infraclavicular brachial plexus using a double-stimulation technique and assess its efficacy. Patients undergoing orthopedic surgery of the upper limb were included in this prospective study. The landmarks used were the coracoid process and the clavicle. The needle was inserted in the direction of the top of the axillary fossa (in relation to the axillary artery), with an angle of 45 degrees. Using nerve stimulation, the musculocutaneous nerve was identified first and blocked with 10 mL of 1.5% lidocaine with 1:400,000 epinephrine. The needle was then withdrawn and redirected posteriorly and medially. The radial, ulnar, or median nerve was then blocked. The block was tested every 5 min for 30 min. The overall success rate, i.e., adequate sensory block in the 4 major nerve distributions at 30 min, was 92%, and 6% of the patients required supplementation. Five patients required general anesthesia. No major complications were observed. This modified infraclavicular brachial plexus block using a double-stimulation technique was easy to perform, had frequent success, and was safe in this cohort.

Adult↗
PubMed2005

Infraclavicular brachial plexus block versus humeral approach: comparison of anesthetic time and efficacy.

UNLABELLED: Most upper arm regional anesthesia techniques are successful and differences in efficacy should not dictate the choice of technique. In the present study, we compared humeral block (HB) and infraclavicular brachial plexus block (ICB) using anesthetic time (i.e., duration of the procedure + onset time) as the primary outcome measure. The block was successful when a complete sensory block was obtained in the four major nerves of the arm, and the time to complete block was recorded. Patients undergoing orthopedic surgery of the upper limb were included in a prospective randomized study and received ICB (group I, n = 60 patients) or HB (group H, n = 60 patients). Total anesthetic time was 19.5 min (95% confidence interval [CI], 17.4-21.6 min) for ICB and 20.8 min (95% CI, 18.7--22.9 min) for HB (not significant). Time to perform the block was 4.5 min (95% CI, 4-5 min) for ICB and 9.8 min (95% CI, 8.9--10.7 min) for HB (P < 0.05). The onset time was 15 min (95% CI, 13-17 min) for ICB and 11 min (95% CI, 9--13 min) for HB (P < 0.05). The success rate was 92% for ICB and 95% for HB (not significant). One self-limited vascular puncture was made in each group. HB had a faster onset time but ICB using a double-stimulation technique was faster to perform. Anesthetic time was similar with the two techniques. IMPLICATIONS: We have compared infraclavicular brachial plexus block (ICB) with humeral block. Efficacy and anesthetic time were not significantly different, although time to perform the block was shorter with the ICB.

Adult↗
PubMed2004

The sciatic nerve block in emergency settings: a comparison between a new anterior and the classic lateral approaches.

BACKGROUND: Anterior and lateral approaches to the sciatic nerve block are performed with the patient in the supine position. This could be an important advantage when mobilization to the limb involved is limited or painful, particularly in emergency conditions. The aim of this prospective, randomized study was to compare these two sciatic nerve blockades performed in an emergency setting. MATERIAL/METHODS: 59 patients undergoing post-traumatic lower extremity surgery under a sciatic nerve block were randomly assigned to either a lateral or an anterior approach. After appropriate positioning of the 150-mm insulated needle using a nerve stimulator, 25 ml of ropivacaine 0.75% were injected. Time to perform the block, sciatic nerve depth, success rate, and patient's comfort were analyzed. RESULTS: The mean time to perform the block was 4.9+/-4.0 min in the anterior group and 6.1+/-6.9 min in the lateral group (NS). The mean depth of sciatic nerve localization was 107+/-17 mm in the anterior group and 91+/-20 mm in the lateral group (P<0.05). Although the success was similar in both group (77% in the anterior group vs 79% in the lateral group), the number of technical failure (sciatic nerve stimulation impossible) was higher with the anterior approach (86% vs 33%; p<0.05). CONCLUSIONS: These data suggest that both techniques are of similar value in an emergency setting.

Adult↗
PubMed2004

Anterior approach to the sciatic nerve block: adaptation to the patient's height.

UNLABELLED: To improve the incidence of block of the posterior femoral cutaneous nerve (PFCN) when using an anterior approach as described recently, we hypothesized that the distance between the inguinal line and the puncture site depends on the patient's height. A preliminary radiological study performed in 13 patients established a formula describing the relationships between the patient's height and the puncture site "S." A line was drawn between the anterior iliac spine and the superior angle of the pubic tubercle (inguinal line) and another line from the midpoint of the inguinal line to the puncture site "S." "S" was calculated from the midpoint of the inguinal line as "S" = (height in cm--100)/10. A prospective study was conducted in 53 patients. Results are presented as median (range, 0.25-0.75). Two minutes were required to locate the sciatic nerve at a depth of 12 cm (10.5-13.0 cm). Complete sciatic and PFCN blocks were observed in 92% of the patients. We conclude that consideration should be given to the patient's height when the sciatic nerve is blocked using an anterior approach. This technique seems to improve the success of block of the PFCN, essential to tolerate a thigh tourniquet. IMPLICATIONS: This prospective but noncomparative work was performed to evaluate a new anterior technique of sciatic block, an adaptation of the anatomic landmarks described by Chelly and Delaunay, to patient height.

Analgesics↗
PubMed2004

Propofol inhibits human platelet aggregation induced by proinflammatory lipid mediators.

Lysophosphatidic acid (LPA), platelet-activating factor (PAF), and thromboxane A(2) are proinflammatory lipid mediators that activate surface receptors on platelets, producing increased intracellular calcium, which is necessary for aggregation. We investigated propofol's effect on platelet aggregation and intracellular calcium mobilization caused by these three agonists. Platelets from human volunteers were incubated in buffers containing LPA (1 microM), U46619 (thromboxane A(2) analog; 1 microM), or PAF (10 nM). Propofol emulsion or 2,6-diisopropylphenol (propofol without fat emulsion) dissolved in ethanol was added to achieve concentrations of propofol used clinically: 5 or 10 microg/mL. After 2 min, aggregation or intracellular calcium concentrations were measured with optical techniques. Propofol emulsion and propofol in ethanol produced similar inhibition of platelet aggregation induced by LPA, PAF, and U46619 in a dose-dependent fashion. LPA, PAF, and U46619 each caused significant increases in intracellular calcium that were not modified by propofol. Because propofol does not significantly alter intracellular calcium increases caused by receptor activation, inhibition appears to act distal to platelet receptors, inositol phosphate 3, and phospholipase C. Because the three lipid mediators play a key role in inflammation, their inhibition by propofol might be clinically important.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2002

Major complications of regional anesthesia in France: The SOS Regional Anesthesia Hotline Service.

BACKGROUND: Several previous surveys have estimated the rate of major complications that occur after regional anesthesia. However, because of the increase in the use of regional anesthesia in recent years and because of the introduction of new techniques, reappraisal of the incidence and the characteristics of major complications is useful. METHODS: All French anesthesiologists were invited to participate in this 10-month prospective survey based on (1) voluntary reporting of major complications related to regional anesthesia occurring during the study period using a telephone hotline service available 24 h a day and managed by three experts, and (2) voluntary reporting of the number and type of regional anesthesia procedures performed using pocket booklets. The service was free of charge for participants. RESULTS: The participants (n = 487) reported 56 major complications in 158,083 regional anesthesia procedures performed (3.5/10,000). Four deaths were reported. Cardiac arrest occurred after spinal anesthesia (n = 10; 2.7/10,000) and posterior lumbar plexus block (n = 1; 80/10,000). Systemic local anesthetic toxicity consisted of seizures only, without cardiac toxicity. Lidocaine spinal anesthesia was associated with more neurologic complications than bupivacaine spinal anesthesia (14.4/10,000 vs. 2.2/10,000). Most neurologic complications were transient. Among 12 that occurred after peripheral nerve blocks, 9 occurred in patients in whom a nerve stimulator had been used. CONCLUSION: This prospective survey based on a free hotline permanent telephone service allowed us to estimate the incidence of major complications related to regional anesthesia and to provide a detailed analysis of these complications.

Acute Disease↗
PubMedDate not supplied

Resident versus staff anesthesiologist performance: coracoid approach to infraclavicular brachial plexus blocks using a double-stimulation technique.

OBJECTIVES: Infraclavicular brachial plexus block with double stimulation (ICB) is a safe technique for upper-limb anesthesia. However, the experience of learning this technique by anesthesiology residents has not been reported. The aim of this study was to compare staff with resident anesthesiologists in the performance of ICB. METHODS: Patients scheduled for orthopedic surgery of the upper limb were included in a prospective, comparative, randomized study and were given ICB by either staff anesthesiologist (Group S, n = 110 patients) or resident anesthesiologist (Group R, n = 110 patients). RESULTS: Time to perform the block was 3.9 minutes (95% confidence interval [CI 95%] = 3.5 to 4.3) for Group S and 5.8 minutes (CI 95% = 5.2 to 6.4) for Group R (P < .05). The onset time was 14.4 minutes (CI 95% = 13.5 to 15.3) for Group S and 15.9 minutes (CI 95% = 14.7 to 17.1) for Group R (P = NS). Success rate was 93% for Group S and 90% for Group R (P = NS). Supplementation was performed in 8 patients in Group S versus 11 patients in Group R (P = NS). No patient needed general anesthesia. One self-limited vascular puncture was made in Group S versus 3 in Group R (P = NS). CONCLUSION: This report determines whether residents can perform this technique with comparable efficiency compared with staff. We conclude that ICB should be taught as part of all resident training programs.

Adult↗