Biomedical subjects

P Aceto

Publications and source records attributed to P Aceto.

6 recordsLinked to original sources

PubMed2005

Changes in hemodynamics during isoflurane and propofol anesthesia: a comparison study.

OBJECTIVES: Volatile anesthetics are thought to impair cerebral autoregulation more than i.v. anesthetics. However, few comparative studies have been carried out in humans. The aim of our study was to evaluate the differences in cerebral hemodynamic changes after introduction of isoflurane (a volatile anesthetic) and propofol (an i.v. anesthetic). METHODS: Eighteen consecutive patients submitted to laparoscopic cholecystectomy were selected. After the induction, anesthesia was maintained by isoflurane (one minimum alveolar anesthetic concentration) during the first part of the surgical operation, and then by propofol (5 mg/kg/hour i.v.). Ventilation was adjusted to maintain a constant end-tidal CO(2). Middle artery flow velocity was assessed by means of transcranial Doppler ultrasonography. Arterial blood pressure, heart rate (HR), capnometry, pulse oxymetry, inspired fraction of O(2), and body temperature, were monitored. RESULTS: Cerebral artery velocity, HR, and mean arterial pressure all significantly increased from baseline after the introduction of isoflurane (p<0.05); the HR and mean arterial blood pressure showed no significant difference between the isoflurane and propofol phases. Isoflurane anesthesia induced a significant increase in cerebral blood velocity. Propofol introduction led to a significant decrease in cerebral artery velocity (p<0.05). CONCLUSIONS: Propofol but not isoflurane decreased cerebral blood velocity thus restoring cerebral autoregulation and the coupling between cerebral blood flow and cerebral metabolism.

Adult↗

PubMed2005

Use of levobupivacaine for the treatment of postoperative pain after thoracotomies.

Continuous thoracic epidural analgesia with an opiod-local anaesthetic mixture is the most appropriate strategy to control postoperative pain in thoracic surgery. Levobupivacaine, the pure S(-) enantiomer of racemic bupivacaine, has less cardiotoxic and neurotoxic potential but similar anaesthetic properties of its native agent. There are no studies in thoracic surgery that had established the minimal efficient concentration of this anaesthetic when used with an epidural opioid. The advantages of administering opioids in addition to local anaesthetics in the epidural space are the possibility to decrease dose and consequently side-effects of each drug and to exploit the documented synergy between these different categories of drugs in producing segmental epidural analgesia. In our departmental study (unpublished data), 2 different concentration of levobupivacaine (Group A: 0.125% and Group B: 0.0625%) combined with sufentanil (1 mg/mL) were administered in continuous epidural post-thoracotomy infusion to investigate quality of analgesia, motor block and side-effects. An intravenous PCA system has been used in the postoperative period to evaluate rescue morphine consumption. Preliminary results showed that patients of each group reported similar VAS at rest although a better pain control during cough resulted in group A. Patients receiving levobupivacaine at 0.125% presented low incidence of nausea, vomiting and pruritus probably because of the smaller amount of rescue morphine administered. At the concentration of 0.125% epidural levobupivacaine in combination with sufentanil allowed to obtain a good pain control with no adverse effects and motor block at all.

Analgesia, Epidural↗

PubMed2004

[Anesthesia and concomitant pathologies: anesthesia in the elderly patient].

With the increase in the average age of the population, more and more older persons undergo surgery. Major surgery, cardiovascular, orthopaedic and abdominal interventions expose the elderly patient to a significant risk for postoperative morbidity and mortality. This is not only related to the advanced age of these subjects, which is a recognized independent risk factor, but also to the aging process itself and to the greater prevalence of heart and lung diseases affecting this population segment. An important role is also played by the so-called physiologic modification found in subjects without recognized illnesses. Reduced organ function reserve requires accurate preoperative assessment that takes into account cardiovascular reserve and physiologic and pathologic alterations in the respiratory system that may predispose the patient to hypoxemia and favour the development of postoperative infection. Moreover, alterations in pharmacokinetics and pharmacodynamics require individualized drug dosing. Particular attention should also be directed at the prevention of postoperative cognitive disorders that favour the development of complications and negatively affect postoperative recovery of body function.

Age Factors↗

PubMed2004

Auditory evoked potentials.

Auditory evoked potentials (AEPs) are an electrical manifestation of the brain response to an auditory stimulus. Mid-latency auditory evoked potentials (MLAEPs) and the coherent frequency of the AEP are the most promising for monitoring depth of anaesthesia. MLAEPs show graded changes with increasing anaesthetic concentration over the clinical concentration range. The latencies of Pa and Nb lengthen and their amplitudes reduce. These changes in features of waveform are similar with both inhaled and intravenous anaesthetics. Changes in latency of Pa and Nb waves are highly correlated to a transition from awake to loss of consciousness. MLAEPs recording may also provide information about cerebral processing of the auditory input, probably because it reflects activity in the temporal lobe/primary cortex, sites involved in sounds elaboration and in a complex mechanism of implicit (non declarative) memory processing. The coherent frequency has found to be disrupted by the anaesthetics as well as to be implicated in attentional mechanism. These results support the concept that the AEPs reflects the balance between the arousal effects of surgical stimulation and the depressant effects of anaesthetics. However, AEPs aren't a perfect measure of anaesthesia depth. They can't predict patients movements during surgery and the signal may be affected by muscle artefacts, diathermy and other electrical operating theatre interferences. In conclusion, once reliability of the AEPs recording became proved and the signal acquisition improved it is likely to became a routine feature of clinical anaesthetic practice.

Anesthesia↗

PubMed2003

Preliminary study on the feeding habits of roe deer (Capreolus capreolus) in the western Alps.

Roe deer feeding habits were studied in the western Alps during the summer season using the faecal analysis method. The diet of cattle grazing in the same area was also investigated and the trophical niche overlap between the two species was determined. The roe deer diet was found very variable and mostly composed of dicotyledons, with Leguminosae and Cistaceae as prevalent species. Monocotyledons, mainly represented by Graminaceae, were consumed to a lesser extent. A significant preference was observed for Cistaceae and other dicotyledons whereas a significant refuse was observed for Graminaceae and Asteraceae. These data confirmed the roe deer's behaviour to select food with a better nutritive value. Despite the differences between the cattle and roe deer's diets, the trophical niche overlap was quite high. This can be explained by the homogeneity of the plants covering the whole area which probably limited food selection by the roe deer.

Animal Feed↗

PubMed2003

Relationship between awareness and middle latency auditory evoked responses during surgical anaesthesia.

BACKGROUND: Some studies support the view that meaningful auditory input can be processed by the brain during apparent surgical anaesthesia. Consequently, patients may be able to remember some information implicitly after anaesthesia as well through a 'dream-like process' (subconscious awareness). The aim of this study was to investigate the presence of subconscious awareness during anaesthesia and to examine its relationship to the mid-latency auditory evoked responses (MLAERs). METHODS: We studied 40 patients, ASA I-II, undergoing laparoscopic cholecystectomy. General anaesthesia was induced with thiopental 5 mg kg(-1), fentanyl 3 micro g kg(-1), and vecuronium 0.08 mg kg(-1). For the maintenance of anaesthesia, patients were randomly assigned to one of four anaesthetic regimen groups: sevoflurane+air in oxygen 40%; sevoflurane+nitrous oxide 60%; isoflurane+air in oxygen 40%; and isoflurane+nitrous oxide 60%. MLAERs were recorded before anaesthesia, at 1 MAC of inhaled anaesthetic and then 30 min after awakening. An audiotape with one of four stories was played immediately after intraoperative MLAER recording. Explicit and implicit memory was assessed 24 h after awakening. RESULTS: None of the patients had explicit recall. One of the patients from the isoflurane-air group showed implicit memory of listening to the audiotape. A dream-like process, in which they remembered implicitly the story played during anaesthesia, occurred in one of the patients from the sevoflurane-nitrous oxide group. In the patients with subconscious awareness, MLAERs were similar to that of the awake state with a Pa latency increase of less than 8.87. When there was a marked increase in Pa latency during anaesthesia, no subconscious awareness was observed. No statistically significant differences were found between Pa latency before and after anaesthesia. CONCLUSIONS: MLAERs may help to predict subconscious cerebral processing of auditory inputs during anaesthesia.

Adolescent↗