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Biomedical subjects

F Giunta

Publications and source records attributed to F Giunta.

At least 37 records · Page 2Linked to original sources
PubMed1992

Energy expenditure and gas exchange measurements in postoperative patients: thermodilution versus indirect calorimetry.

OBJECTIVE: To compare a method of measuring energy expenditure and gas exchange using the Fick principle with the standard indirect calorimetry technique. DESIGN: Prospective study of a consecutive sample of postoperative patients. Oxygen consumption (VO2), CO2 production (VCO2), respiratory quotient, and energy expenditure were derived from measurements of variables, including oxygen content and cardiac output. Energy expenditure and gas exchange were measured simultaneously by continuous indirect calorimetry over a 60-min period. SETTING: Surgical ICU in a university hospital. PATIENTS: Twenty-six consecutive patients (45 to 80 yrs) who underwent sustained surgical trauma. Excluded from the study entry were patients with time-related fluctuations of hemodynamic variables, poor cooperation, patients who required supplemental oxygen, or mechanical ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: While the measurements of VO2 and VCO2 by calorimetry and thermodilution were significantly correlated with one another (for VO2, r2 = .93, p less than .001; for VCO2, r2 = .26, p less than .01), VO2 and VCO2 values by indirect calorimetry were consistently greater than VO2 and VCO2 values by the Fick method (p less than .01). The respiratory quotient calorimetric measurements ranged between 0.69 and 0.99, whereas the corresponding thermodilution measurements spread to impossible values, from 0.24 to 1.30 (0.821 +/- 0.07 vs. 0.740 +/- 0.24, p less than .05). There was an insignificant relationship (r2 = .06, p = .21) between the values of respiratory quotient by the two methods. A strong, positive correlation between energy expenditure measured by indirect calorimetry and energy expenditure measured by the Fick method was observed (r2 = .92, p less than .001). The limit of agreement between the two methods was -0.24 +/- 73 kcal/day/m2 (-1.00 +/- 305 kJ/day/m2). CONCLUSIONS: In postoperative patients, while VO2 and energy expenditure measurements by thermodilution are easy to perform and accurate for clinical purposes, VCO2, and respiratory quotient measurements are too imprecise and inaccurate to serve any useful function. Therefore, in those clinical situations in which an evaluation of respiratory quotient and substrate utilization may be useful for purposes of metabolic care of the surgical patient, precise measurements of gas exchange with indirect calorimetry are mandatory.

Calorimetry, Indirect↗
PubMed1991

Digital X-ray apparatus especially designed for precise biometry in stereotactic surgical procedures.

Modern stereotactic surgical procedures were developed mainly because digital CT image gave us the opportunity to recognize the morphology and the site of a brain lesion, and, at the same time, CT offered a very easy and reliable way to calculate target coordinates because the brain scans are digital maps. Digital x-ray image obtained with an x-ray-intensifier and a TV Analog/Digital converter is not suitable for stereotactic use because image distortion is multifactorial and it is impossible to rectify. We have developed a new apparatus (Neurogil) for intra-operative use that is able to produce a digital image on a display, the measures displayed match exactly with the patient's brain. A linear array of 1024 photodiodes is working in front of an x-ray source and it collects the density image of the patient's head positioned between them. It shows the patient's head with the stereotactic frame exactly as a radiogram, but no distortion is present. Digital brain angiograms are possible with electronic subtraction, mathematical enhancement and with a stereoscopic view on a particular display. Any kind of mathematical calculation or computer-graphic application is possible. A special software was developed for stereotactic closed and open surgery.

Cephalometry↗
PubMed1991

Open stereotactic neurosurgery: 57 cases.

The two main neurosurgical tools are the operative microscope and stereotactic apparatus. The operative microscope is essential in cisternal or ventricular surgery and the stereotactic apparatus is essential in approaching intracerebral lesions. Both given their best performance when the one aids the other. Small convexity lesions are best approach with stereotactic aid, and excellent microsurgical intracerebral lesions can be debulked with the operative microscope. Malignant tumours pursue their inevitable course but slow growing tumours and angiomas may have long survival even with one subtotal removal. The major problem in removing slow-growing tumors is the difficulty in distinguishing tumour from normal brain, but the stereotactic guide is useful in delimitating tumour volume. The results in 57 cases are described.

Brain Neoplasms↗
PubMed1991

Intracranial meningiomas associated with glial tumours: a review based on 54 selected literature cases from the literature and 3 additional personal cases.

The simultaneous occurrence of meningioma and glioma is extremely rare. Three new cases and 54 adequately described in the literature are analyzed. Clinical diagnosis may be difficult due to discrepancy between clinical and radiological findings. Unexpected clinical deterioration following removal of a tumour and relapse simulating recurrence may occur. The introduction of CT technology does not seem to have offered the expected contribution to the early diagnosis of these coincidental lesions, at least before the introduction of the newer generation scanners or MRI. While removal of both tumours in one session yielded the best results, surgery for the sole glioma appeared to be associated with an unacceptably high mortality. Although several aetiopathogenetic hypotheses have been suggested for explaining this curious association, coincidental meningioma and glioma are most likely to be different primary brain tumours occurring randomly in the same individual.

Adult↗
PubMed1989

Brain stem expanding lesions: stereotactic diagnosis and therapeutical approach.

In most cases of brain stem expansive lesion a surgical approach is possible, but in each patient it must be evaluated if the surgical risk is proportional to the therapeutic result. Sometime surgery is limited to a biopsy sample, particularly in malignant lesions. We started stereotactic serial biopsy sampling in all CT or NMR intraaxial brain stem expansive lesions as a preliminary diagnostic procedure. The aim is to look for benign well delimited lesions that we consider for surgical removal or to drain haematomas and abscesses. 35 patients with brain stem expansive lesions were submitted to 47 surgical procedures: 35 stereotactic biopsies (one each patient) and, among them, 12 were major surgical procedures (with craniotomy) for microsurgical removal of the expansive lesions. 15 patients were in paediatric age. Suboccipital transcerebellar approach was performed in 25 mesencephalic, pontine, bulbar expansive lesions and frontal approach was limited to 10 thalamo-mesencephalic lesions. There was no mortality. Two patients were stereotactically drained and definitively cured.

Adolescent↗
PubMed1989

Clinical uses of high frequency jet ventilation in anaesthesia.

Since 1981, high frequency jet ventilation (HFJV) has been used in 300 patients undergoing surgery, most commonly during i.v. general anaesthesia for endoscopy and surgery of the airways: laryngoscopy, bronchoscopy, laryngeal microsurgery and laser surgery (more than 230 patients); repair of tracheal stenosis, tracheal sleeve pneumonectomy and tracheal sleeve lobectomy. HFJV was administered through a narrow injection catheter inserted in the airway, with a second rigid catheter positioned distally to the injector in the airway for gas sampling and measurement of airway pressure. In all subjects gas exchange was satisfactory, even during tracheoplasty and bronchoplasty.

Adolescent↗
PubMed1988

Brain stem expansive lesions: stereotactic biopsy for a better therapeutic approach.

CT diagnosed brain stem malignant lesions were in the past almost always treated with radiation therapy (RT). Eventually this turned out to be a grave mistake. With stereotactic serial biopsies of all brain stem expanding lesions we have been able to verify the histological nature in all cases but two and to prevent a blind therapeutic approach. In 24 patients bearing CT diagnosed expansive lesions into the brain stem 68 samples were taken during 24 stereotactic procedures. In 8 patients surgical removal of the expanding lesion was attempted after stereotactic biopsy.

Adolescent↗
PubMed1988

Metabolic control during total parenteral nutrition: use of an artificial endocrine pancreas.

The metabolic impact of total parenteral nutrition (TPN) was evaluated in nine subjects who underwent esophagogastroplasty for esophageal carcinoma. On the second day after operation all subjects were connected to an artificial endocrine pancreas. In four patients only glucose was infused (5.5 mg/kg X min). The remaining five subjects received glucose (4.0 mg/kg X min), amino acid (0.5 mg/kg X min), and lipid emulsion (0.6 mg/kg X min). Plasma glucose concentration was kept constant over 24 hours. However, both insulin requirement (111 +/- 15 v 70 +/- 2 mU/kg X h) and plasma insulin level (99 +/- 15 v 30 +/- 7 microU/mL; P less than .01) were higher during combined TPN. Blood lactate concentration was higher during glucose infusion (P less than .05). No difference was found in blood concentrations of pyruvate, alanine, and ketone bodies. Both glycerol and FFA were higher during combined TPN. The ratio between glucose infusion rate and the average plasma insulin level was calculated as an index of insulin-mediated glucose metabolism; G/I X 100 was markedly reduced during combined TPN (4.5 +/- 0.8 v 20.7 +/- 3.7; P less than .05). Plasma FFA levels were positively correlated with plasma insulin concentration (r = .76) and inversely correlated to G/I X 100 (r = -.73; both P less than .05). In conclusion, during combined TPN a state of insulin resistance is induced and more insulin is required to achieve a normal glucose utilization.

Blood Glucose↗
PubMed1987

Stereotactic computer graphic system with brain maps.

We have developed a stereotactic computer graphic system with brain maps that runs on a personal computer. This system consists of three parts: 1. firmware for dizitizing radiological films with a TV camera or scanner (when digital image is not directly obtained from floppy disks); 2. software for introducing or processing brain maps by matching them with CT or NMR images; 3. hardware. Our system is designed to: 1. recognize the relevant frame points and calculate targets, their volume and surgical instrument trajectory; 2. match between brain maps of an ideal brain and patient's CT or NMR images with visible and invisible pathology; 3. monitor during surgery the position of the surgical instrument or target modification. The whole procedure and processed images are stored in a data-base for further study.

Brain Mapping↗
PubMed1987

Transcerebellar biopsy in the posterior fossa: 12 years experience.

Utilizing the Leksell stereotactic system, the transcerebellar approach was used for posterior fossa biopsies. During a period of 12 years, a total of 29 patients were operated on by this technique, among them 12 children. In the adult, the procedure was carried out with the patient awake and sitting upright; the pediatric patients required general anesthesia and the head was supported either manually or by a clamp. Representative specimens were obtained in all cases but one, showing a wide diagnostic spectrum. As a rule, the procedures were performed smoothly, with no serious side effects. Stereotactic biopsies in the posterior fossa, hitherto seldom performed, open new diagnostic perspectives, one of which is for use in obscure brain stem lesions. The transcerebellar approach has been proven to be easy, direct, and safe provided an appropriate technique is used, such as that described in the present paper.

Adolescent↗