Search PubMed⌕ Search

Biomedical subjects

P Petit

Publications and source records attributed to P Petit.

At least 145 records · Page 8Linked to original sources
PubMed1995

Standard doses versus repeated high doses of epinephrine in cardiac arrest outside the hospital.

Among all of the cathecolamines used for cardiac arrest treatment, epinephrine injection during cardio-pulmonary resuscitation is currently the most powerful means of enhancing effectiveness; however, deliberations about the optimal dosage have recently become intense. In the SAMU of Lyon (F), we conducted a double blind prospective randomized study over an 18-month period, comparing repeated standard-dose epinephrine (1 mg) and repeated high-dose epinephrine (5 mg) in the management of cardiac arrest outside the hospital. Five-hundred thirty-six patients were enrolled with 265 in the standard-dose group and 271 in the high-dose group; both groups are globally similar. One-hundred eighty-one (33.8%) patients returned to spontaneous circulation (R.O.S.C.); 85 in the standard-dose group (32%) and 96 in the high-dose group (35.5%). One-hundred nineteen patients (22.2%) were admitted; 54 in the standard-dose group (20.4%) and 65 in the high-dose group (24%). At 6 months nine patients (7.6%) were alive; three patients from the standard-dose group (5.5%) and six from the high-dose group (9.2%). We never noticed cardiac or neurologic adverse effects with the high doses. The results of this study are not statistically significant, but we observed a marginal trend towards repeated 5 mg epinephrine doses. A large French multicentre study is now necessary.

Adult↗
PubMed1995

[Diagnosis of heart arrest caused by CO2 embolism during laparoscopic surgery by monitoring of aortic blood flow and capnography].

We report the case of a 25-year-old woman undergoing a laparoscopic cholecystectomy, who suffered, one min after the beginning of intraperitoneal insufflation of CO2 (2.5 L at a pressure of 10 mmHg), a sudden decrease to 0.8 L.min-1 of the aortic blood flow (ABF), monitored in the descending aorta by an oesophageal echo-Doppler probe, associated with a decrease of PetCO2 to 15 mmHg and of SpO2 readings to 88%. Despite the lack of simultaneous changes in heart rate and arterial pressure, pulmonary gas embolism (GE) was suspected. The pneumoperitoneum was exsufflated and CPR was started because of circulatory inefficiency. Ten min later, efficient spontaneous cardiac activity restarted, whereas PetCO2 and ABF returned rapidly to normal values. At this time, a typical gas noise was clearly obtained through the oesophageal Doppler transducer. The patient remained in deep coma (GCS:6) with a left sided hemiplegia. However, she fully recovered after four sessions of hyperbaric oxygenation. Simultaneous continuous monitoring of ABF and PetCO2 allows an undelayed recognition of major circulatory disturbances, before significant changes in heart rate and arterial pressure occur.

Adult↗
PubMed1995

The biochemistry of programmed cell death.

Programmed cell death (PCD) is involved in the removal of superfluous and damaged cells in most organ systems. The induction phase of PCD or apoptosis is characterized by an extreme heterogeneity of potential PCD-triggering signal transduction pathways. During the subsequent effector phase, the numerous PCD-inducing stimuli converge into a few stereotypical pathways and cells pass a point of no return, thus becoming irreversibly committed to death. It is only during the successive degradation phase that vital structures and functions are destroyed, giving rise to the full-blown phenotype of PCD. Evidence is accumulating that cytoplasmic structures, including mitochondria, participate in the critical effector stage and that alterations commonly considered to define PCD (apoptotic morphology of the nucleus and regular, oligonucleosomal chromatin fragmentation) have to be ascribed to the late degradation phase. The decision as to whether a cell will undergo PCD or not may be expected to be regulated by "switches" that, once activated, trigger self-amplificatory metabolic pathways. One of these switches may reside in a perturbation of mitochondrial function. Thus, a decrease in mitochondrial transmembrane potential, followed by mitochondrial uncoupling and generation of reactive oxygen species, precedes nuclear alterations. It appears that molecules that participate in apoptotic decision-making also exert functions that are vital for normal cell proliferation and intermediate metabolism.

Apoptosis↗
PubMed1995

An imidazopyridine anxiolytic alters glucose tolerance in patients: a pilot investigation.

We have recently shown that compounds with high affinity for peripheral-type benzodiazepine receptors inhibited glucose-induced insulin secretion in vitro. We therefore performed an oral glucose tolerance test in anxious inpatients treated with the imidazopyridine derivative alpidem, which has been shown to display high affinity for these binding sites. The test was performed before and after 1 week of daily administration of the drug. As compared with pretreatment values, a significant alteration of the insulin response to glucose was observed. It is suggested that daily administration of alpidem, at therapeutically effective doses for the treatment of anxiety, may alter glucose tolerance.

Adult↗
PubMed1995

[Problems caused by anesthesia of patients with severe burns].

The treatment of severe burns requires repeated and various surgical procedures under general anaesthesias. Requirements differ according to the evolution phase of the burnt lesion. Three first post-traumatic days are marked by a major oedema and a large haemodynamic instability. Hypovolemia during 12 to 24 hours is followed by an hyperkinetic phase. The secondary period can last several weeks to several months before the cutaneous recovery is complete. Septic risk is then major and dénutrition constant. Problems raised by surgery differ according to the type of surgery: early excision of deep bums, bath therapy, skin graft, dressing. These procedures are often haemorrhagic and painful. Thermal status is constantly threatened. This type of pathology interferes with the pharmacology of anaesthetic drugs. Hypoprotidemia and change of protein-binding modify drug kinetics. Continuous use of opiates and sedatives is source of tolerance and tachyphylaxis. The number of acetylcholine receptors is increased, contraindicating the use of depolarizing muscle relaxants and often induces a resistance to the nondepolarizing muscle relaxants. The knowledge of these alteration leads to discuss indications of anaesthetics, analgesics and muscle relaxants most frequently used in these patients. During anaesthesia the positioning of the patient takes into account the surgical needs. Hypothermia prevention is mandatory. Peroperative resuscitation is dominated by maintenance of haemodynamic balance, compensation of hydroelectrolytic and blood losses, treatment of septic complications. Should be the same who has in change the patient in the intensive care unit.

Anesthesia, General↗
PubMed1995

[Improving tissue perfusion without invasive monitoring. Apropos of a case].

A case is reported of a 64 year old patient who suffered a septic shock after surgical treatment of a biliary peritonitis. Increasing myocardial contractility and aortic blood flow by dobutamine appeared ineffective; added norepinephrine infusion improved the peripheral perfusion. This clinical improvement in tissue perfusion was evaluated by non-invasive continuous monitoring of the haemodynamic profile, combining aortic blood flow measurement by a transoesophageal echo-Doppler and continuous measurement of end-tidal carbon dioxide.

Carbon Dioxide↗
PubMed1995

[Vasoconstrictor effect of uridine triphosphate on pancreatic vascular bed].

Purinoceptors have been classified according to their sensitivity to structural analogues of purines. In addition to the well established and widely distributed P2 purinoceptor subtypes (P2X and P2Y), the existence of "pyrimidine" or "nucleotide" receptors was proposed, which are sensitive to the pyrimidine nucleotide, uridine triphosphate (UTP). Recently, this class of receptor has been included in the P2 purinoceptor classification as a P2U subtype. We have previously shown that pancreatic vascular resistance was modulated by the activation of P2Y and P2X purinoceptors, inducing vasodilation and vasoconstriction respectively. In this study, we investigated the effect of pyrimidine nucleotides on pancreatic vessels. The experiments were performed on isolated rat pancreas perfused at a constant pressure, which was selected to obtain a stable flow rate of 2.5 ml/min before drug administration; thus, any change in pancreatic vascular resistance resulted in a change in the flow rate. UTP induced a decrease in the flow rate at all concentrations tested, but the kinetics differed according to the concentration. The lowest concentration used (16.5 microM) induced a delayed, progressive and long lasting vasoconstriction. Ten times and one hundred times higher concentrations (165 and 1,650 microM) induced an immediate, more pronounced and also long lasting vasoconstriction. In contrast, the other pyrimidine nucleotide cytosine triphosphate (16.5 and 165 microM) did not significantly modify the pancreatic flow rate. This study suggests the presence of a P2U purinoceptor on rat pancreatic vessels; this P2U receptor differs from the P2X receptor since the activation of this latter elicits only a transient vasoconstriction.

Animals↗
PubMed1994

Prognostic significance of early cardiac index measurements in severely burned patients.

Invasive monitoring during early resuscitation was performed. To compare the heamodynamic results of severely burned patients, the results of 38 patients hospitalized between 1988 and 1991 in the burn centre of Lyon were retrospectively reviewed. Survivors and non-Survivors' data were compared. No difference existed between the two groups in age, unit burn score, fluid requirement and dose of dobutamine. Survivors had a significantly higher cardiac index, O2 delivery and systolic blood pressure index than non-survivors. It is suggested that the ability to sustain a high cardiac index in response to the burn injury plays a role in the outcome of the patients. There is an indication that dobutamine could have a beneficial effect in this way. Further studies are needed to confirm the benefit of the maintenance of high cardiac index levels by the pressors.

Adult↗
PubMed1994

[Use of Diprivan for prehospital emergencies].

The use of propofol at the scene of an accident or during transport to the hospital: 1. Should be restricted to fully qualified anaesthetists of an Emergency Mobile Hospital Unit. 2. Is probably rather limited, as: the indications for anaesthesia in this context are relatively rare; they are dominated by trauma cases (which represent 20 to 30 per cent of the activity of an Emergency Mobile Hospital Unit) and other accident-related conditions; furthermore, in most emergency situations, sedation and/or analgesia of varying depth are more often required; the indications for propofol would be rare because of: its haemodynamic effects, especially as hypovolaemia is extremely frequent, as neurological damage is often existing, and the medical history of the patient is frequently unknown; the possible choice of other agents, such as midazolam, which is widely used as well as etomidate or ketamine; 3. Should follow the same guidelines as those in use for its intra-hospital administration: propofol is undoubtedly a valuable agent as it allows a rapid induction, depresses the pharyngo-laryngeal reflexes, and has the advantage of producing a rapid, good quality recovery which provides an important element of safety; however, for as long as prospective comparative studies have not specifically been carried out in the area of pre-hospital anaesthesia, the greatest circumspection is required. Any contraindication and precaution recommended from hospital use should be strictly adhered to and amplified because of the difficult circumstances and the other available alternatives kept in mind.

Drug Approval↗
PubMed1994

A double-blind comparison of clonazepam and placebo in the treatment of neuroleptic-induced akathisia.

The present study was designed to investigate the efficacy of clonazepam in neuroleptic-induced akathisia. Twelve patients were treated during 2 weeks with clonazepam or placebo in a double-blind randomized design. Akathisia was scored by an independent rater before and after treatment, as well as 1 week after medication withdrawal. Clonazepam (0.5-2.5 mg/day) induced a significantly higher reduction in the akathisia scores than placebo (p < 0.05). One week after stopping the drug, there was a partial but significant relapse in the treated group as compared with controls, in whom the symptoms remained stable. In addition, the clinical improvement was significantly correlated with the daily dose of clonazepam (rs = 0.827; p < 0.002). These results support the potential usefulness of clonazepam in the treatment of neuroleptic-induced akathisia and suggest an optimal daily dose in the range of 10-40 micrograms/kg.

Adult↗
PubMed1994

Mild phenotype and normal gonadal function in females with 4p trisomy due to unbalanced t(X;4)(p22.1;p14).

In this report we describe the mild phenotypic manifestations and normal gonadal function in a 50-year-old mother and her 17-year-old daughter with 4p trisomy resulting from an unbalanced t(X;4)(p22.1;p14) mat. Late replication of the der(X) was demonstrated by BrdU incorporation with spreading of the late replication to the 4p portion as an explanation of the reduced effect of the trisomy 4p/monosomy Xp on the physical and secondary sexual development in both patients.

Adolescent↗
PubMed1994

Purinergic receptors on insulin-secreting cells.

The insulin secreting B cell is fitted with the two types of purinergic receptors: P2 (for ATP and/or ADP) and P1 (for adenosine). The activation of P2 purinoceptors by ATP or ADP evokes a biphasic stimulation of insulin secretion from isolated perfused rat pancreas; this stimulation is dose-dependent between 10(-6) and 10(-4) M. Non hydrolysable structural analogues are also effective, and the relative potency of various agonists (2-methylthio ATP >> ATP = ADP = alpha, beta-methylene ATP >> AMP) gave evidence for a P2y purinoceptor subtype. Proposed mechanisms include both an increased Ca2+ uptake and an increased intracellular Ca2+ mobilization via the hydrolysis of polyphosphoinositides. ATP (or ADP) potentiates physiological insulin-secreting agents (glucose and acetylcholine) and P2 purinoceptors could play a physiological role in the stimulation of insulin secretion. The activation of P1 purinoceptors (adenosine receptors) decreases insulin secretion. Using structural analogues of adenosine, the receptor was characterized as an A1 subtype; it is coupled to a pertussis toxin sensitive G protein and it inhibits adenylate cyclase. It is of physiological relevance that the B cell has the two types of purinoceptors with opposite effects. Recently, a metabolically stable structural analogue of ADP, adenosine-5'-0-(2-thiodiphosphate) or ADP beta S, has been described as a potent secretory agent, effective at nanomolar concentrations on isolated perfused rat pancreas. In vivo, this substance is able to increase insulin secretion and to improve glucose tolerance after IV administration in rats and oral administration in dogs. Furthermore in streptozotocin-induced diabetes. ADP beta S retains its insulin secreting effects. These results suggest that P2y purinoceptors could be a new target for antidiabetic drugs.

Adenine Nucleotides↗
PubMed1994

Splenic vein thrombosis after splenectomy: frequency and role of imaging.

PURPOSE: To assess the frequency of splenic vein thrombosis (SVT) after splenectomy and its consequences on patient treatment. MATERIALS AND METHODS: A group of 183 consecutive patients who underwent splenectomy were evaluated. Of these patients, 119 underwent postoperative ultrasound (US) or computed tomography. RESULTS: SVT was diagnosed in 13 of 119 patients in the first 2 weeks after surgery. In these 13 patients, splenectomy had been performed for hematologic disorders (n = 12) or trauma (n = 1). Seven of the 13 patients were asymptomatic. After anticoagulant therapy, follow-up US of 12 patients showed resolution of thrombosis with no complications in 10 patients; two patients developed cavernous transformation of the portal vein. CONCLUSION: Since only 65% of patients underwent imaging, the true frequency of SVT could not be determined; however, it occurred in at least 7% of patients who underwent splenectomy. Routine Doppler US should be performed after splenectomy to allow early anticoagulant therapy in patients with SVT.

Humans↗