PubMed Health⌕ Search

Biomedical subjects

L Martinelli

Publications and source records attributed to L Martinelli.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of capacitive versus resistive joint contact stress sensors.

Cartilage contact stress elevations might be associated with pain or other symptoms after malunited, incongruous intraarticular fractures. Studies identifying fractures with patterns of elevated contact stresses would help to ensure more appropriate choices of treatment. However, appropriate instrumentation for such studies is crucial. We tested two such systems, one capacitive and one resistive, under identical loading conditions presumed to occur in the ankle. We used a materials testing machine and customized-loading fixtures to measure force detection error, contact area error, repeatability, homogeneity, creep, and one-axis and two-axis bending artifacts. The loading regimen caused pressures up to 2.5 MPa. An error in force detection between -3% and +5% was observed with the capacitive sensor whereas an error between -12% and +20% was observed with the resistive sensor. Repeatability and homogeneity were greater for the capacitive sensor. Errors in contact area measurement were less than 2% for the resistive sensor and less than 6% for the capacitive sensor. The resistive sensor could not conform to spherical surfaces without crinkling. Creep artifact was observed with both sensors. We concluded that the capacitive sensor had superior performance even though its thickness and high compliance may be disadvantageous in intraarticular measurements. The resistive sensor is required for use where higher pressures are expected despite its inferior accuracy.

Ankle Joint↗
PubMed2005

High epidural thoracic anesthesia for pericardial surgery.

Here are reported three cases involving patients (77, 61 and 58 years-old) with recurrent pericardial effusion who underwent pleuropericardial window using thoracic epidural anesthesia (T1-T2 o T2-T3) while fully awake, without endotracheal intubation. The operative and postoperative courses were uneventful. During the pneumothoracic phase the vital parameters and spontaneous ventilation patterns remained the same compared to the basic ones. Pain control was excellent. On the basis of this early experience the authors conclude that thoracotomy in awake patients to reach the cardiac structures is a reproducible technique.

Aged↗
PubMed2004

The post-prandial state in Type 2 diabetes and endothelial dysfunction: effects of insulin aspart.

OBJECTIVE: Recently, much attention has been focused on the possibility that the post-prandial state may be a cardiovascular risk factor in diabetes. The aim of the present study was to evaluate whether the post-prandial state is associated with endothelial dysfunction in patients with diabetes and to explore the effect on this aspect of managing post-prandial hyperglycaemia by insulin aspart. RESEARCH DESIGN AND METHODS: Twenty-three patients with Type 2 diabetes and 10 normal controls were recruited. In the diabetic patients two different tests were performed in each subject: a standard meal preceded by subcutaneous injection of soluble insulin (0.15 U/kg body weight) or of short-acting insulin aspart (0.15 U/kg body weight). These tests were designed to achieve different levels of post-prandial hyperglycaemia. Controls received a single standard meal test. Immediately before, and 1, 2, 4 and 6 h after each meal, blood glucose, triglycerides, free fatty acids and flow-mediated vasodilation were measured. RESULTS: Compared with regular insulin, insulin aspart significantly reduced the area under the curve for post-prandial hyperglycaemia (58.3 +/- 17.6 vs. 68.1 +/- 17.7; P<0.04), and preserved flow-mediated vasodilation, which was decreased in the post-prandial state (39.4 +/- 2.9 vs. 34.1 +/- 2.2; P<0.01). Triglyceride and free fatty acid levels were not differentially affected by the treatment. In normal controls the meal did not affect flow-mediated vasodilation. CONCLUSION: This study shows that the post-prandial state is accompanied by endothelial dysfunction in Type 2 diabetic patients and that insulin aspart improved endothelial function.

Diabetes Mellitus, Type 2↗
PubMed2001

[Control of postoperative pain in heart surgery. Comparison of analgesics].

BACKGROUND: Evaluation of the efficacy of three analgesic drugs (tramadol, ketorolac, and morphine) for the control of postoperative pain in cardiac surgery. METHODS DESIGN: prospective randomized study. SETTING: University Hospital, Postoperative intensive care unit. PARTICIPANTS AND INTERVENTION: sixty patients, who underwent cardiac surgery, were studied. They were randomly allocated in four groups, treated with a different postoperative analgesic therapy: A) tramadol in continuous infusion; B) ketorolac in continuous infusion; C) tramadol, in repeated boluses; D) morphine, in repeated boluses. MEASUREMENTS: the analgesic efficacy of each drug and administration protocol was evaluated by hemodynamic stability, arterial blood gases analysis, Visual Analogue Scale (VAS), resting and after cough, the VAS derivatives PID and SPID, the concentration of plasma epinephrine and norepinephrine, at eight postoperative times. Adverse effects were also registered. RESULTS: Only tramadol, in continuous i.v. infusion, achieves the required analgesic effect, significantly decreasing both VAS scores, at the end of the administration of the drug. This treatment reduced epinephrine plasma levels in the first postoperative day, when the residual analgesic effect of surgical anesthesia can be considered disappeared. CONCLUSIONS: Tramadol in continuous infusion (dose 12 mg/h) proved to be effective for the control of postoperative pain after cardiac surgery. The proposed dose represents a good compromise between analgesic efficacy and interference with the vital functions of operated patients.

Adult↗
PubMed2000

Coronary artery narrowing after aortic root reconstruction with resorcin-formalin glue.

Severe stenosis of right and left main coronary artery ostia developed after aortic root reconstruction with gelatin-resorcin-formol glue for correction of acute type A aortic dissection. Surgical treatment of this condition required grafting of the right and left anterior descending arteries with bilateral mammary arteries on the beating heart.

Adult↗
PubMed2000

Pulsatile normothermic cardiopulmonary bypass and plasma catecholamine levels.

The aim of the study was to assess plasma catecholamine levels in patients undergoing myocardial revascularization and relate them to pulsatile (P) and nonpulsatile (NP) normothermic cardiopulmonary bypass (CPB). Twenty-eight patients were randomly assigned to different CPB management: 15 patients were assigned to group 'P', 13 patients to group 'NP'. During normothermic extracorporeal circulation, group 'P' received pulsatile perfusion, while group 'NP' received nonpulsatile perfusion. Levels of epinephrine and norepinephrine were evaluated during the operation and in the intensive care unit (ICU), at seven time points. Haemodynamic assessment was performed at four time points in the same period. Demographic and surgical data were collected, and the postoperative course was analysed. Epinephrine levels were markedly increased during CPB in both groups, while norepinephrine increased more in group NP in comparison with group P. No significant difference was found in fluid administration, transfusion, drugs usage, or postoperative complications. Normothermic pulsatile CPB seems to achieve reduced levels of norepinephrine. A clinical beneficial effect of this finding was not demonstrated during the study.

Adult↗
PubMed2000

[A reduction in the invasiveness during surgical revascularization: the harvesting of the great saphenous vein by a video endoscopic technic].

BACKGROUND: The authors report their preliminary experience of endoscopic saphenous vein harvesting as part of a program devoted to reducing the invasivity of surgical myocardial revascularization. This method allows us to minimize the cutaneous incisions in the inferior limbs necessary to harvest the saphenous vein, thus reducing the incidence of complications. METHODS: The study includes 41 patients who underwent endoscopic saphenous vein harvesting from October 1998 to September 1999 and, as a control group, 20 patients with similar characteristics operated on with the traditional technique during the same period. The variables considered were: the time necessary to harvest the saphenous vein, the incidence of complications, and the postoperative mobilization. RESULTS: All the endoscopically harvested grafts were adequate for the scheduled procedure. The only complication occurred in a patient operated on with the traditional technique. The time of harvesting and the day of mobilization were similar in the two groups. The reduction of surgical trauma allowed a fast deambulation recovery and better esthetic results. CONCLUSIONS: When complete arterial revascularization is not feasible, the endoscopic harvesting of the required saphenous vein segment allows for a significant reduction in the invasivity of the procedure.

Adult↗
PubMed1999

The role of antithrombin III in the perioperative management of the patient with unstable angina.

BACKGROUND: To evaluate the effectiveness of intraoperative administration of antithrombin III (AT III) to improve anticoagulation and preserve the hemostatic mechanisms during cardiopulmonary bypass (CPB) in patients with unstable angina under heparin treatment. METHODS: We divided 22 patients, scheduled for coronary artery bypass grafting, into two groups. Group A (11 patients) received 3000 International Units (IU) of AT III concentrates plus heparin before aortic cannulation. Group B (11 patients) received only heparin. Blood drainage, allogeneic blood transfusions, and intraoperative activated coagulation time were recorded. Also, AT III, thrombin-antithrombin complex (TAT), fragment 1.2 (F 1.2), and D-dimers were measured during the operation and the first postoperative day. RESULTS: Group A patients had fewer transfusions and had less chest-tube drainage. In group A, AT III levels increased after AT III concentrates administration and were always higher than in group B. In group B, F 1.2 and TAT increased significantly more after CPB and at the end of operation. Differences in D-dimers between the groups were not significant. CONCLUSIONS: Intraoperative administration of AT III concentrates allowed adequate anticoagulation during CPB and attenuated the coagulative cascade activation and the consequent consumptive coagulopathy.

Angina, Unstable↗
PubMed1999

Superior extension of intraoperative brain damage in case of normothermic systemic perfusion during coronary artery bypass operations.

OBJECTIVE: Despite the controversies on the potential detrimental effects of normothermic cardiopulmonary bypass on neurologic outcome, to date no correlation between the severity of intraoperative brain lesions and the cardiopulmonary bypass temperature used at operation has been reported. This study compares the prevalence and the severity of brain lesions in patients who underwent operation in condition of normothermic versus hypothermic systemic perfusion. METHODS: Data are derived from the analysis of 2987 consecutive primary isolated myocardial revascularizations performed at our institution between April 1990 and January 1997. Of these cases, 1385 procedures were hypothermic and 1602 procedures were normothermic systemic perfusion. In all cases the neurologic outcome and extent of ischemic areas were prospectively recorded. RESULTS: Overall, 31 patients had a perioperative stroke (1.0%). The prevalence of neurologic events was similar in the 2 groups (15 cases in the hypothermic group and 16 cases in the normothermic perfusion group; P, not significant). However, the mean Glasgow Outcome Scale score and computed tomography-demonstrated extent of brain lesions were significantly worse in the normothermic group. CONCLUSIONS: Although the prevalence of intraoperative stroke was similar with hypothermic or normothermic cardiopulmonary bypass, the use of normothermic systemic perfusion was associated with more extended brain damage at computed tomographic scan and with a worse neurologic outcome. These results demand caution in the use of normothermic cardiopulmonary bypass and claim further investigation on the neurologic safety of normothermia.

Brain Ischemia↗
PubMed1999

Hypnosis instead of general anaesthesia in paediatric radiotherapy: report of three cases.

PURPOSE: This report proposes hypnosis as a valid alternative to general anaesthesia for immobilisation and set-up in certain cases in paediatric radiotherapy. METHODS: We report three cases of children who underwent radiotherapy in 1994 and were treated using hypnosis for set-up during irradiation. The first and the second were two cases of macroscopic resection of cerebellar medulloblastoma in which craniospinal irradiation was necessary, while the third patient suffered of an endorbitary relapse of retinoblastoma previously treated with bilateral enucleation, radiotherapy and chemotherapy; in this last situation the child needed radiation as palliative therapy. Hypnosis was used during treatment to obtain the indispensable immobility. Hypnotic conditioning was obtained by our expert psychotherapist while the induction during every single treatment was made by the clinician, whose voice was presented to the children during the conditioning. RESULTS: Every single fraction of the radiation therapy was delivered in hypnosis and without the need for narcosis. CONCLUSIONS: Hypnosis may be useful in particular situations to prepare paediatric cancer patients during irradiation, when lack of child collaboration might necessitate the use of general anaesthesia and when anaesthesia itself is not possible.

Anesthesia, General↗
PubMed1999

Clinical pharmacokinetics of tacrolimus in heart transplant recipients.

We report pharmacokinetic data on tacrolimus in 14 heart transplant patients (2 women, 12 men). The median age and the median body weight were 55.5 years (range, 23-61 years) and 67.0 kg (55-79 kg), respectively. All patients were maintained on a triple-drug protocol (tacrolimus, azathioprine, and prednisone), with a 7-day antithymocyte globuline induction. The first tacrolimus dose, administered orally 1 to 5 days posttransplant, ranged from 0.03 to 0.4 mg/kg (median = 0.052 mg/kg). The maintenance dose ranged from 0.03 to 0.13 mg/kg/day (administered in two equal doses) to achieve blood levels of 5 of 20 ng/ml, as determined by a microparticle enzyme immunoassay (MEIA). Whole blood samples were drawn just before, at 0.5 hour, and at 1, 2, 3, 4, 6, 8, 10, and 12 hours after the administration of the first dose; trough levels were measured thereafter. The mean oral clearance (CL/F) and apparent volume of distribution (Vd/F) averaged 0.21+/-0.08 L/hour/kg and 2.4+/-0.8 L/kg while the half-life averaged 8.7+/-3.5 hours. Tacrolimus accumulation index during chronic therapy (Rac = Cmin(steady state)/Cmin(first dose) normalized to the same dose) averaged 1.3. Eighty-eight percent of the trough blood levels measured in our patients were within 5 and 20 ng/ml. The incidence of rejection in the study population was extremely low: a prevalence of grade 2 rejection or more, of 0.4+/-0.8 episodes/ patient was observed after a follow-up period of 8.8+/-2.2 months. Only one patient experienced severe renal toxicity, probably because of his preoperative precarious hemodynamic status. Pharmacokinetic data suggest that maintenance tacrolimus daily dose should be equal to 0.1 mg/kg/day to obtain trough blood concentrations of approximately 10 ng/ml. Inter- and intra-patient variability of tacrolimus blood concentration should be expected and justify careful monitoring.

Adult↗
PubMed1998

Influence of type of surgery on the occurrence of parasympathetic reinnervation after cardiac transplantation.

BACKGROUND: Cardiac autonomic reinnervation after human cardiac transplantation has been demonstrated frequently but to date only for sympathetic efferents. Standard surgical techniques leave many parasympathetic branches intact in the original atria and thus with less stimulus to reinnervate the donor atria. METHODS AND RESULTS: We used changes in the RR-interval power spectrum induced by sinusoidal modulation of arterial baroreceptors by neck suction at different frequencies to detect both parasympathetic and sympathetic reinnervation in 79 subjects with "standard" and 10 "bicaval" heart transplants. In 24 subjects (17 standard and 7 bicaval), the protocol was repeated 6 and 11 months after transplantation. Neck suction at 0.20 Hz produced a component at 0.20 Hz in the RR-interval spectrum not due to respiration (fixed at 0.25 Hz), which suggested parasympathetic reinnervation, in 4 of 10 bicaval but in only 2 of 79 standard transplant subjects (whose recipient atria underwent >50% resection to remove scars of previous interventions), P<.001. In only 1 (bicaval) transplant subject was parasympathetic reinnervation present 6 months after transplantation (confirmed 3 months later); in 4 subjects, it was absent at 6 months but appeared after 11 months after transplantation. Atropine (0.04 mg/kg i.v.) abolished the response to fast (0.20 Hz) and reduced that to slow stimulation, confirming the presence of parasympathetic reinnervation (4 subjects). CONCLUSIONS: Parasympathetic reinnervation depends on the surgical technique: because bicaval surgery cuts all sympathetic and parasympathetic nerves, regeneration might be stimulated similarly in both branches. Standard surgery cuts only approximately 50% of sympathetic fibers; most recipient parasympathetic axons remain intact, hence their regeneration might not be stimulated.

Atropine↗
PubMed1998

European Multicenter Tacrolimus (FK506) Heart Pilot Study: one-year results--European Tacrolimus Multicenter Heart Study Group.

BACKGROUND: Tacrolimus (FK506) may represent a major advance in the management of allograft rejection after solid organ transplantation. In August 1994 a European heart transplantation pilot study was initiated to assess the efficacy and safety of tacrolimus when administered exclusively through an oral route. METHODS: Eighty-two heart transplant recipients were randomized to treatment (2:1 ratio) with either tacrolimus- (n=54) or cyclosporine-based therapy (n=28). RESULTS: No significant differences were evident between the two treatment groups in either rejection or survival rates at 1 year. Kaplan-Meier estimates of the freedom from rejection were 26.3% and 18.5%, respectively, for the tacrolimus and cyclosporine treatment groups (p=.444). Survival rates were 79.6% and 92.9% (p=.125). At 3 of the 5 centers, patients received antithymocyte globulin during the immediate postoperative period and fared better than those who did not (with acute rejection-free rates of 49.2% and 26.7% for tacrolimus and cyclosporine, respectively [p=.080], as opposed to 7.1% and 8.3% [p=.965]; patient survival rates of 84.6% and 93.3% [p=.382] vs 75.0% and 92.3% [p=.243]). The overall rates of infection, impaired renal function (31.5% vs 21.4%), and glucose intolerance (7.0% vs 4.3%) did not differ significantly between the tacrolimus and cyclosporine treatment groups. Tacrolimus seemed to possess an advantage with regard to a reduced requirement for antihypertensive therapy (59.5% vs 87.5%, p=.025). CONCLUSIONS: Immunosuppression with oral tacrolimus provides a viable alternative to treatment with cyclosporine, particularly when administered in conjunction with antibody therapy. Further studies are warranted to optimize the administration of tacrolimus in this indication.

Administration, Oral↗
PubMed1998

Tepid systemic perfusion and intermittent isothermic blood cardioplegia in coronary surgery.

BACKGROUND: To evaluate the safety and effectiveness of tepid perfusion and isothermic blood cardioplegia in coronary surgery. METHODS: We studied 200 patients undergoing myocardial revascularization: 100 procedures were performed with moderate systemic hypothermia (28 degrees C) and cold crystalloid cardioplegia (4 degrees C); the other 100 patients received tepid systemic perfusion (TP) (34 degrees C) and intermittent blood cardioplegia at the same temperature according to the minicardioplegia technique (Group 2). The two groups were comparable with regards to age, extent of disease, preoperative left ventricular function and extra-corporeal circulation (ECC) time. RESULTS: In the tepid group we observed a higher incidence of spontaneous resumption of cardiac rhythm at cross-clamp removal compared to the hypothermic group (93% vs 34%; p<0.001). No difference was found in cardiac index at specified intervals, myocardial enzymes, inotrope requirements, arrhythmias, need for vasopressors and postoperative blood loss. Fluid balance at the end of ECC was significantly lower in the tepid group (343+/-635 ml vs 883+/-925 ml; p<0.001). Hospital mortality and morbidity were the same in the two groups. CONCLUSIONS: Our data suggest that TP and isothermic blood cardioplegia represent a simple, safe and effective method of systemic and myocardial protection which may be an alternative to traditional hypothermia.

Aged↗
PubMed1997

Conventional left atrial versus superior septal approach for mitral valve replacement.

BACKGROUND: This study was designed to evaluate the safety and effectiveness of the superior septal approach for routine mitral valve replacement. METHODS: One hundred forty-six consecutive patients undergoing mitral valve replacement at our institution were randomly assigned to undergo the procedure using either the conventional left atriotomy or the superior septal approach. Postoperatively and during the follow-up, 12-lead electrocardiography, 24-hour Holter monitoring, and transthoracic and transesophageal echocardiography were performed in all patients. RESULTS: The cardiopulmonary bypass and cross-clamp times were significantly higher in the superior septal group. No significant difference in blood loss was found between the two groups, and no residual atrial septal defect was found in patients in whom we used the superior septal approach. The maintainance of sinus rhythm at late follow-up and the incidences of postoperative arrhythmias and newly developed atrioventricular block were not significantly different between the two groups. CONCLUSIONS: The use of the superior septal approach to the mitral valve is not associated with a greater incidence of rhythm disturbances or other complications. Because this approach provides optimal exposure of the valve and the subvalvular apparatus, it has been routinely adopted for use in patients undergoing mitral valve replacement at our institution.

Adult↗
PubMed1997

Staged discharge out of hospital of the Novacor left ventricular assist system (LVAS) recipients.

The mobility afforded by the wearable Novacor LVAS provides the possibility for the recipients to leave the hospital, with undoubted improvements in their quality of life. A staged program for discharging LVAS recipients from the hospital has been set up at the Policlinico San Matteo of Pavia together with the Rehabilitation Center of Montescano and Baxter Novacor Service support, in order to proceed smoothly towards patient's self sufficiency and to minimize any associated risk. The steps are: stay in the hospital ward, discharge to Rehabilitation Center and discharge to home. Several excursions with and without an LVAS team member are encouraged before final discharge to home. Simple criteria of eligibility must be fulfilled to move to the next step. Every move towards a reduced presence of specialized personnel includes an appropriate training of the patient and relatives and a technical checkout of the needed equipment. During the stay at the Rehabilitation Center primarily the physical training and psychological preparation are taken care of by means of tailored programs. When the patient is discharged to home, the check of patient condition is performed weekly at the Rehab Center, bloodwork and technical evaluation is assessed once every two weeks and technical inspections at home twice per year. Complications are reported as in hospital protocol. Control parameters of the LVAS are reported only in case of alarms or abnormal operation. Periodic review of patient training is performed during the check visits, mostly focused on how to address emergency situations. The hospital is responsible for providing one LVAS operator available on call (all hours). Up to date, 11 patients received an implant of LVAS, 9 of them with the wearable system. All of these 9 patients made excursions out of the hospital and 4 patients have successfully undergone the staged program, showing a satisfactory general condition and restoration to social life.

Adult↗