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Biomedical subjects

P Coriat

Publications and source records attributed to P Coriat.

At least 19 recordsLinked to original sources
PubMed1995

Inhibition of platelet aggregation by inhaled nitric oxide in patients with acute respiratory distress syndrome.

BACKGROUND: Nitric oxide inhibits platelet adhesion and aggregation in vitro. The aim of this prospective study was to assess the platelet antiaggregating activity of nitric oxide administered to patients with acute respiratory distress syndrome (ARDS) at increasing concentrations. METHODS: In six critically ill patients (mean age 37 +/- 16 yr) with ARDS (lung injury severity score > or = 2.2), the lungs were mechanically ventilated with inhaled nitric oxide (1, 3, 10, 30, and 100 ppm) randomly administered. Patients with cardiac dysrhythmias, septic shock, an underlying hemostasis disorder (constitutive or acquired), a platelet count less than 100 Giga/l, or a decreased platelet aggregation and those treated with antiplatelet or anticoagulant agents were excluded. Platelet aggregation was measured without nitric oxide and at each nitric oxide concentration in platelet-rich plasma issued from radial artery. Ivy bleeding time using a horizontal incision was simultaneously performed. RESULTS: After nitric oxide, a non-dose-dependent but statistically significant decrease in ex vivo platelet aggregation induced by three aggregating agents was observed: adenosine diphosphate = -56 +/- 18%, collagen = -37 +/- 18%, and ristocetin = -45 +/- 18% (P < 0.05). In each individual, Ivy bleeding time remained within normal values measured in healthy volunteers, and variations after nitric oxide did not correlate with changes in platelet aggregation. Simultaneously, arterial oxygenation improved significantly and pulmonary artery pressure decreased significantly. CONCLUSIONS: In patients with ARDS and without preexisting coagulation disorders, the beneficial effects of inhaled nitric oxide on arterial oxygenation and pulmonary circulation are associated with a significant inhibition of platelet aggregation. This antithrombotic effect is not associated with a significant prolongation of the bleeding time.

Acute Disease↗
PubMed1995

Dose-response curves of inhaled nitric oxide with and without intravenous almitrine in nitric oxide-responding patients with acute respiratory distress syndrome.

BACKGROUND: Inhaled nitric oxide, a selective pulmonary vasodilator, in combination with intravenous almitrine, a selective pulmonary vasoconstrictor, markedly improves arterial oxygenation in 50-60% of patients with acute lung injury. The goal of this study was to assess dose response of inhaled nitric oxide with and without almitrine in patients with acute respiratory distress syndrome responding to nitric oxide. METHODS: Six critically ill patients (aged 44 +/- 7 yr) were studied during early stage of their acute respiratory failure (Murray score: 2.6 +/- 0.1). All responded to 15 parts per million (ppm) of inhaled nitric oxide by an increase in Pao2 of at least 40 mmHg at FIo2 1. Hemodynamic and respiratory parameters were recorded continuously from pulmonary artery and systemic catheters. Inspiratory, expiratory, and mean intratracheal nitric oxide concentrations were monitored continuously using a fast response time chemiluminescence apparatus (NOX 4000, Sérès, Aix-en-provence, France). On day 1, 6 inspiratory concentrations of nitric oxide were randomly administered: 0.15, 0.45, 1.5, 4.5, 15, and 45 ppm to determine the dose response of inhaled nitric oxide on Pao2, pulmonary shunt, mean pulmonary artery pressure, and pulmonary vascular resistance index. On day 2, a continuous intravenous infusion of almitrine at a dose of 16 micrograms.kg-1.min-1 was administered and dose response to inhaled nitrix oxide was repeated according to the same protocol as during day 1. A constant FIo2 of 0.85 was used throughout the study. RESULTS: Nitric oxide induced a dose-dependent increase in Pao2 for inspiratory nitric oxide concentrations ranging between 0.15 and 1.5 ppm. Almitrine increased Pao2/FIo2 from 161 +/- 30 to 251 +/- 45 mmHg (P < 0.001) and pulmonary vascular resistance index from 455 +/- 185 to 527 +/- 176 dyn.s.cm-5.m2 (P < 0.05), and decreased pulmonary shunt (Qs/QT) from 35 +/- 2 to 33 +/- 3% (P < 0.001). During almitrine combined with nitric oxide, a dose-dependent increase in Pao2 was observed for inspiratory nitric oxide concentrations ranging between 0.15 and 1.5 ppm. Almitrine plus nitric oxide 1.5 ppm increased Pao2/FIo2 from 161 +/- 30 to 355 +/- 36 mmHg (P < 0.001), decreased Qs/QT from 35 +/- 2 to 24 +/- 2% (P < 0.001), pulmonary vascular resistance index from 455 +/- 185 to 385 +/- 138 dyn.s.cm-5.m2 (P < 0.05), and mean pulmonary artery pressure from 31 +/- 4 to 28 +/- 4 mmHg (P < 0.001). CONCLUSIONS: In 6 patients with early acute respiratory distress syndrome and highly responsive to inhaled nitrix oxide, the administration of intravenous almitrine at a concentration of 16 micrograms.kg-1.min-1 induced an additional increase in Pao2. Dose response of nitric oxide was not changed by the administration of almitrine and a plateau effect was observed at inspiratory nitric oxide concentrations of 1.5 ppm.

Administration, Inhalation↗
PubMed1995

Circulatory effects of desflurane.

The cardiovascular properties of desflurane and some other inhalational anaesthetics are outlined and compared, and the way in which they may be effectively used in clinical practice is considered. Desflurane appears to offer some advantages compared with currently available anaesthetics. Its effects on left ventricular function are moderate and the solubility of the agent in blood and tissue is remarkably less than isoflurane, enflurane, or halothane.

Anesthesia↗
PubMed1994

Aprotinin to decrease bleeding and intraoperative blood transfusion requirements during descending thoracic and thoracoabdominal aortic aneurysmectomy using cardiopulmonary bypass.

The purpose of this retrospective study was to assess the efficacy of aprotinin, an antifibrinolytic agent, in reducing bleeding and blood transfusion requirements in patients undergoing descending thoracic or thoracoabdominal aortic aneurysmectomy using cardiopulmonary bypass (CPB). Sixty-nine consecutive patients underwent thoracic or thoracoabdominal aneurysmectomy using CPB in a 2-year period. None of the 29 patients operated on in 1990 (group 1) received aprotinin, whereas all 40 patients operated on in 1991 (group 2) were placed on a high-dose regimen of aprotinin. There were no significant differences between the two groups. Administration of aprotinin was associated with a decrease in CPB time (p = 0.02), surgical duration (p = 0.05) and intraoperative blood loss (p = 0.008) as well as a reduction in intraoperative packed red cells (p = 0.01), Cell-Saver units (p = 0.05), fresh-frozen plasma units (p = 0.002), and platelet concentrate (p = 0.01) requirements. These data suggest that aprotinin is effective in reducing bleeding and blood transfusion requirements during descending thoracic or thoracoabdominal aortic aneurysmectomy using CPB.

Adult↗
PubMed1994

[Interferences between angiotensin-converting enzyme inhibitors and spinal anesthesia].

To determine whether angiotensine converting enzyme inhibition (ACEI) therapy should be continued up to the time of the surgical procedure, a standard practice for other modern antihypertensive agents, it should be known whether stopping the treatment does or does not lead to a hypertensive episode before surgery or at intubation and whether continuing treatment is or is not associated with an unacceptable fall in blood pressure at induction. Data from the literature obtained in patients chronically treated for essential hypertension with captopril or enalapril demonstrate that withdrawal of ACEI therapy before surgery does not result in a higher incidence of hypertensive episodes both preoperatively and at intubation. In contrast, an increased need for ephedrine to maintain blood pressure at induction is observed in patients who receive ACEI together with their premedication. This exaggerated hypotensive response to induction is in agreement with previous studies in anaesthetized subjects which have shown that angiotensin II contributes to hemodynamic regulation during general and epidural anaesthesia. It might also be the consequence of the specific effects of ACEI therapy on the loading conditions of the heart and/or the autonomic nervous system. It must be emphasized that both ACEIs and epidural anaesthesia dilate large arteries as capacitance vessels and increase vagal tone. The decreased tone in capacitance vessels accentuates the drops in blood pressure provoked by general or epidural anaesthesia through an increase in blood pooling at the expense of cardiac filling. This mechanism is enhanced by the presence of either a preoperative hypovolemia or a disturbed left ventricular diastolic function, which are two abnormalities frequently seen in hypertensive vascular surgical patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Epidural↗
PubMed1992

Transesophageal echocardiographic assessment of left ventricular function in response to labetalol for control of postoperative hypertension.

Although labetalol (LAB), the combination of an alpha- and beta-adrenergic blocking agent, is thought to be effective and safe for the control of postoperative hypertension, no study has focused on changes in left ventricular (LV) function when this drug was used to control postoperative hypertension. Therefore, this study determined the effects of LAB on hemodynamics and LV function assessed by 2D transesophageal echocardiography (TEE) in 17 patients undergoing abdominal aortic surgery who experienced a postoperative hypertensive episode. Postoperatively, patients were transferred while still intubated and under fentanyl sedation to the postanesthesia care unit where a TEE probe was inserted to provide a short-axis view of the LV. When their systolic blood pressure increased above 165 mmHg for more than 4 minutes, LAB was given in a dose of 0.75 mg/kg IV, over 2 minutes. If the blood pressure was not lowered to within 10% of the preoperative values, additional doses of LAB were given. Control of hypertension was obtained in all patients and was associated with a significant decrease in heart rate (90 +/- 19 to 70 + 13 bpm), cardiac index (4.52 +/- 1.65 to 3.36 +/- 1.55 L/min/m2), and mixed venous oxygen saturation (73 +/- 10 to 63 +/- 10%). With the lower blood pressure, end-diastolic area increased, indicating myocardial depression. In conclusion, LAB can be used to effectively control hypertension during the early postoperative period after abdominal aortic surgery. However, the reduction of blood pressure is achieved principally by the negative inotropic effect of LAB, which predominates over its vasodilator action.

Adult↗
PubMed1992

Dipyridamole-thallium-201 scintigraphy in the diagnosis and prognosis of coronary artery disease in patients undergoing noncardiac surgery.

Although most of the published studies using DTS as a preoperative screening test show various shortcomings, the following conclusions can be drawn: 1. DTS should not be used as a routine preoperative test in vascular surgical patients. DTS possesses insufficient accuracy when used in patients without clinical findings suggestive of CAD. 2. DTS may prove more useful in stratifying patients with an intermediate probability of developing cardiac complications. In such a population the test will not offer an "all or nothing" linear results, but rather, when included with the clinical findings and the nature of the surgical procedure, a complex stratification. 3. Because of progress in the perioperative management of high-risk patients, positive findings on preoperative DTS may not correlate perfectly with perioperative cardiac occurrences. 4. Because several factors influence thallium uptake after dipyridamole, DTS does not have perfect specificity, which leads to the prescribing of an excessive number of coronary angiographies. Some patients will be seen as having a false-positive DTS test. 5. The use of DTS as a preoperative screening test leads to cardiac catheterization and hence to revascularization independent of symptomatology. Studies must be undertaken to determine whether this approach will improve short- and long-term patient survival.

Coronary Disease↗
PubMed1991

Combined epidural and general anesthesia versus general anesthesia for abdominal aortic surgery.

The goal of this randomized study of high-risk surgical patients was to determine whether intraoperative thoracic epidural anesthesia in combination with light general anesthesia alters postoperative morbidity when compared to a standard technique of "balanced" general anesthesia. A total of 173 patients scheduled for abdominal aortic reconstruction were admitted to the study; 86 were to receive "balanced" general anesthesia (group 1) and 87 thoracic epidural anesthesia in combination with light general anesthesia (group 2). Preoperative evaluation included standard clinical tools, dipyridamole thallium gammatomography, and radionuclide angiography. In these patients, all of whom had peripheral artery disease, there were no significant differences in associated coronary artery disease, hypertension, and cardiovascular treatment. The distribution of left ventricular ejection fraction and the number of patients with thallium redistribution were not statistically different between the two groups. During the postoperative period, group 1 received analgesia of subcutaneous morphine (n = 35), epidural fentanyl (n = 30), or epidural bupivacaine (n = 21). In group 2, 6 patients with a nonfunctioning epidural catheter due to technical failure received a balanced general anesthesia and were eliminated from the study. During the postoperative period, group 2 received analgesia of subcutaneous morphine (n = 26), epidural fentanyl (n = 25), or epidural bupivacaine (n = 30). Cardiovascular morbidity did not differ between the two groups: 22 patients in group 1 and 19 patients in group 2 had a major postoperative cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Comparison of isoflurane with sodium nitroprusside for controlling hypertension during thoracic aortic cross-clamping.

The aims of this randomized study were (1) to determine if isoflurane is effective in controlling blood pressure during thoracic aortic cross-clamping, and (2) to compare its effects on hemodynamics and oxygen transport to those of sodium nitroprusside. Sodium nitroprusside (SNP group, n = 10) or isoflurane (ISO group, n = 10) was started 2 minutes before cross-clamping and was adjusted to maintain systolic arterial pressure as near as possible to preinduction values. The duration of thoracic aortic cross-clamping was 26 +/- 4 minutes in the SNP group and 30 +/- 4 minutes in the ISO group. Administration of isoflurance and sodium nitroprusside was stopped 2 minutes before unclamping. The same anesthetic technique using fentanyl, 6 micrograms/kg, flunitrazepam, 0.02 mg/kg, pancuronium, 0.1 mg/kg, and 50% N2O was used for all patients. At the time of clamping, either isoflurance (maximal expired concentration, 2.5% +/- 0.3%) or sodium nitroprusside (cumulative dose, 11.1 +/- 1.0 mg) was effective in maintaining the systolic blood pressure below 160 mm Hg, whereas the pulmonary capillary wedge pressure did not change. However, only SNP was able to bring the arterial pressure above the cross-clamp back to postinduction levels. During clamping, stroke index values were similar in both groups, but cardiac index increased only in patients receiving SNP. In both groups, at clamping and unclamping, PvO2 was higher than postinduction values, indicating that throughout the study the oxygen needs of the perfused area were adequately met. There was no evidence of acute left ventricular decompensation because pulmonary capillary wedge pressures did not abruptly increase, nor did pulmonary edema occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Abdominal↗
PubMed1990

[Postoperative cardiac insufficiency. The value of enoximone].

The authors discuss the physiopathological mechanisms of intra and postoperative cardiac failure and the different means of treatment. A distinction is made between the intra and postoperative periods: the factors which predispose to cardiac failure are different and the immediate postoperative period would seem to be the most dangerous in patients with reduced coronary or contractile reserves. Enoximone is a valuable and effective inotropic agent in this situation.

Acute Disease↗
PubMed1989

[Monitoring of mixed venous oxygen saturation in aortic surgery: value and limits].

This study aimed to determine perioperative changes in mixed venous oxygen saturation (SvO2) in patients undergoing aortic surgery. Continuous SvO2 monitoring was carried out using an Oximetrix pulmonary catheter. Fourteen patients were randomly assigned to 2 groups, group I (n = 7) patients being given a thoracic epidural anaesthetic with a supplementary general anaesthetic, and group II (n = 7) a general anaesthetic as usual. In both groups, SvO2 increased at induction. In group I patients, SvO2 decreased during surgery to less than 60% (n = 2) and less than 70% (n = 4). This fall was corrected by volume loading and intravenous ephedrine. The intraoperative decrease in SvO2 occuring in 2 group II patients was due to a fall in haematocrit in one, and a propranolol infusion in the other. Although patients in group I were all extubated early after the end of surgery (85 +/- 35 min), the lowest value of SvO2 after extubation was always greater than 60%. Patients undergoing aortic surgery under thoracic epidural anaesthesia can be extubated early, without markedly depressing peripheral reserves in oxygen extraction.

Anesthesia, Epidural↗
PubMed1989

Perioperative cardiac complications of surgical repair of infrarenal aortic aneurysms.

From 1985 to 1987, 261 patients (241 male, 20 female; mean age 66.5 years, range 38-90 years) were hospitalized for elective repair of infrarenal aortic aneurysms. One-hundred forty seven patients (56%) had coronary artery disease, attested to by past history of myocardial infarction or angina pectoris, electrocardiographic signs at rest, or abnormalities of dipyridamole thallium scintigraphy (performed in 72 patients). Ten patients had coronary arteriography and one patient then underwent aortocoronary bypass. Only two patients were not offered operation. All patients operated on had perioperative monitoring using Swan-Ganz catheters. Forty-five patients (17.5%) had a total of 62 postoperative events related to coronary artery disease. These included 40 cases of myocardial ischemia (15%), 16 cases of left heart failure (6%), and six myocardial infarctions (2%). There were nine (3.4%) postoperative deaths, four of which were due to cardiac causes (1.5%). In spite of the frequency of preexisting coronary artery disease and of intra- or postoperative myocardial ischemia, surgical repair of abdominal aortic aneurysm was not responsible for increased perioperative cardiac morbidity or mortality. In this population of aged patients, abdominal aortic aneurysm repair does not necessitate extending the indications for preoperative coronary arteriography or aortocoronary bypass.

Adult↗