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J P Viale

Publications and source records attributed to J P Viale.

At least 19 recordsLinked to original sources
PubMed2006

Effects of increased intra-abdominal pressure on central circulation.

BACKGROUND: In an experimental model we investigated the effects of a gradual increase in intra-abdominal pressure (IAP) on the central circulation. METHODS: Seven pigs were anaesthetized, mechanically ventilated and instrumented. IAP was gradually increased by 5 mm Hg up to 30 mm Hg by abdominal banding in normovolaemic animals, and then they were made hypovolaemic after blood withdrawal. Right atrial pressure (RAP) and left ventricular end-diastolic pressure (LVEDP) at each step and aortic, femoral and inferior vena cava blood flows were measured. Left ventricular end-diastolic area (LVEDA) was determined using epicardial echocardiography. RESULTS: Cardiac output maintained at mild IAP was reduced to 76 (24)% of the initial value at 30 mm Hg IAP [mean (sd)] in normovolaemic animals, and 72 (22)% (P<0.001) in hypovolaemic animals. In normovolaemic animals the LVEDA and LVEDP were significantly increased at an IAP of 10 and 15 mm Hg by 26 (24)% and 38 (23)%, respectively. At these IAP values, the difference between the RAP and IAP was positive. When this gradient became negative, that is beyond 15 mm Hg in normovolaemia and for all IAP values in hypovolaemic animals, the LVEDA declined, reaching 78 (16)% and 62 (22)% (P<0.05) of the initial values in normovolaemic and hypovolaemic groups at the highest IAP value. CONCLUSIONS: These results showed that a gradual increase in IAP led to a redistribution of abdominal blood volume towards the thoracic compartment, at IAP lower than 15 mm Hg in normovolaemia, and at its expense at higher values of IAP. In hypovolaemia there was no thoracic compartment gain. Whereas the absolute or transmural RAPs were not informative of the direction of this blood shift, an RAP greater than IAP was associated with an intrathoracic compartment gain.

Abdomen↗
PubMed2006

Spontaneous baroreflex cardiac sensitivity in end-stage liver disease: effect of liver transplantation.

BACKGROUND AND OBJECTIVE: End-stage liver disease is associated with an imbalance in the autonomic nervous system. The purpose of this study was to estimate the effect of liver transplantation on this imbalance. METHOD: The study involved 10 patients undergoing liver transplantation and 9 patients without liver impairment undergoing liver surgery. The spontaneous baroreflex sensitivity was measured before and 1 month after surgery for the liver surgery group; before and 1, 3, 6, 12 and 18 months after orthotopic liver transplantation. RESULTS: The spontaneous baroreflex slope of patients with end-stage liver disease was decreased before liver transplantation compared to the liver surgery group (3.9 +/- 2.5 ms mmHg(-1) vs. 9.9 +/- 5.0 ms mmHg(-1), P = 0.002). The mean slope was significantly increased at 12 and 18 months compared to the pre-transplantation value (3.9 +/- 2.5 ms mmHg(-1) vs. 8.1 +/- 6.6 ms mmHg(-1) and 7.4 +/- 4.8 ms mmHg(-1), respectively; P = 0.042). Nevertheless, further analysis of individual data showed that only four patients exhibited a marked increase in their baroreflex slope 12 months after the liver transplantation whereas it remained decreased in the six others. CONCLUSIONS: These results confirm that the baroreflex sensitivity is depressed in end-stage liver disease in line with an autonomic nervous system imbalance. The liver transplantation reverses this disturbance only in some patients.

Analysis of Variance↗
PubMed2005

Low-dose ketamine failed to spare morphine after a remifentanil-based anaesthesia for ear, nose and throat surgery.

BACKGROUND: Ketamine has been claimed to prevent acute opioid tolerance and hyperalgesia following acute exposure to opioids and its use has been proposed to decrease postoperative morphine consumption. METHODS: We conducted a randomized, double-blind, controlled study to evaluate the effect of intravenous (i.v.) ketamine on postoperative pain for 48 h after major ear, nose and throat (ENT) surgery. Thirty-one patients received i.v. ketamine 0.15 mg kg(-1) before induction and 2 microg kg(-1) min(-1) during anaesthesia, and 31 patients were administered placebo in a similar manner. Anaesthesia was standardized with remifentanil and propofol, but without nitrous oxide. Standardized postoperative analgesia included paracetamol, methylprednisolone and morphine administered via a patient controlled analgesia (PCA) device. RESULTS: Intra-operative remifentanil consumption was not different between the ketamine group (0.25 +/- 0.07 microg kg(-1) min(-1)) and the control group (0.22 +/- 0.07 microg kg(-1) min(-1)). In the postoperative period, both groups experienced an identical pain course evolution. Cumulative morphine consumption was not significantly different between groups: at 24 h it was 33.3 +/- 14.9 with ketamine and 31.9 +/- 15.3 mg in controls, at 48h it was 40.4 +/- 20.6 mg with ketamine and 42.5 +/- 25.9 mg in controls. CONCLUSION: Low-dose ketamine added to a remifentanil-based propofol anaesthesia did not reduce morphine consumption after major ENT surgery.

Aged↗
PubMed2004

[Perioperative administration of betablockers: a practice survey].

OBJECTIVES: To evaluate the anaesthesiologists' attitude concerning the perioperative administration of betablockers (BB), especially prophylactic BB, in order to prevent postoperative cardiac complications. METHODS: A questionnaire including 20 items was sent to 700 anaesthesiologists of 4 French departments (Ain, Isere, Loire et Rhone). RESULTS: The response rate was 30%. Eighty-eight percent of respondents prescribed the BB with the premedication, on the day of the surgery in patients who were on regular BB. Before major surgery, 37% percent of respondents always or usually introduced prophylactic BB in patients with high cardiac risk. Atenolol was the drug of choice for 68% of perioperative BB users. Seventy-one percent of anaesthesiologists using prophylactic BB asked for a cardiologic opinion before starting BB therapy. CONCLUSION: In practice, anaesthesiologists continued BB during the perioperative period in patients who were on chronic treatment with BB. However, prophylactic perioperative administration of BB in patients with high cardiac risk is still inadequate and dependent on a cardiologic opinion.

Adrenergic beta-Antagonists↗
PubMed2004

Amniotic fluid embolism during caesarean section.

Amniotic fluid embolism occurs rarely but is a leading cause of maternal mortality. A high index of clinical suspicion is necessary to make an early diagnosis to reduce morbidity and mortality. We report a non-fatal case of amniotic fluid embolism occurring during a caesarean section, with special emphasis on the mode of development and diagnosis. The initial presentation of this syndrome was a coagulopathy, followed by the usual complications of massive bleeding. Although non-specific, the diagnosis of amniotic fluid embolism was supported by the observation of amniotic fluid in the central venous blood as well as in the broncho-alveolar fluid.

Adult↗
PubMed2002

Epidural analgesia with 0.15% ropivacaine plus sufentanil 0.5 microgram ml-1 versus 0.10% bupivacaine plus sufentanil 0.5 microgram ml-1: a double-blind comparison during labour.

BACKGROUND: Ropivacaine has been claimed to produce less motor block than bupivacaine during epidural analgesia. However, this advantage has not been clearly confirmed in obstetric studies using low analgesic concentrations in a ratio close to that suggested to be equianalgesic. METHODS: This double-blind, randomized, prospective study was performed in 140 parturients who requested epidural analgesia. After a lumbar epidural catheter had been placed, patients received either 0.10% bupivacaine plus sufentanil 0.5 microgram ml-1 or 0.15% ropivacaine plus sufentanil 0.5 microgram ml-1 followed by a continuous infusion. Additional boluses were used for inadequate levels of analgesia. Visual analogue pain scores, motor block, level of sensory block, supplementary boluses and main characteristics of labour were recorded. RESULTS: No differences were observed between the two groups for pain scores, total volume of anaesthetic solution used [59 (23) and 57 (24) ml in the bupivacaine and ropivacaine groups respectively], duration of labour, mode of delivery, side-effects or satisfaction score. The incidence of motor block was not statistically different between the groups (54 and 69% in the bupivacaine and ropivacaine groups respectively, P = 0.07). However, when motor block occurred, survival analysis showed that it occurred sooner in the course of labour with ropivacaine compared with bupivacaine (log rank test, P = 0.012). CONCLUSION: Combined with sufentanil 0.5 microgram ml-1, 0.10% bupivacaine and 0.15% ropivacaine produce effective and equivalent analgesia during labour, with similar incidences of motor block.

Adult↗
PubMed2000

Within-breath arterial PO2 oscillations in an experimental model of acute respiratory distress syndrome.

Tidal ventilation causes within-breath oscillations in alveolar oxygen concentration, with an amplitude which depends on the prevailing ventilator settings. These alveolar oxygen oscillations are transmitted to arterial oxygen tension, PaO2, but with an amplitude which now depends upon the magnitude of venous admixture or true shunt, QS/QT. We investigated the effect of positive end-expiratory pressure (PEEP) on the amplitude of the PaO2 oscillations, using an atelectasis model of shunt. Blood PaO2 was measured on-line with an intravascular PaO2 sensor, which had a 2-4 s response time (10-90%). The magnitude of the time-varying PaO2 oscillation was titrated against applied PEEP while tidal volume, respiratory rate and inspired oxygen concentration were kept constant. The amplitude of the PaO2 oscillation, delta PaO2, and the mean PaO2 value varied with the level of PEEP applied. At zero PEEP, both the amplitude and the mean were at their lowest values. As PEEP was increased to 1.5 kPa, both delta PaO2 and the mean PaO2 increased to a maximum. Thereafter, the mean PaO2 increased but delta PaO2 decreased. Clear oscillations of PaO2 were seen even at the lowest mean PaO2, 9.5 kPa. Conventional respiratory models of venous admixture predict that these PaO2 oscillations will be reduced by the steep part of the oxyhaemoglobin dissociation curve if a constant pulmonary shunt exists throughout the whole respiratory cycle. The facts that the PaO2 oscillations occurred at all mean PaO2 values and that their amplitude increased with increasing PEEP suggest that QS/QT, in the atelectasis model, varies between end-expiration and end-inspiration, having a much lower value during inspiration than during expiration.

Animals↗
PubMed1999

Liver transplantation resolves the hyperdynamic circulation in hereditary hemorrhagic telangiectasia with hepatic involvement.

BACKGROUND & AIMS: Hepatic involvement in hereditary hemorrhagic telangiectasia is common but often asymptomatic. However, in some cases, the vascular lesions that involve the liver may lead to high-output cardiac failure and pulmonary hypertension that is predominant over hepatobiliary manifestations. Liver transplantation and treatment of these complications are described and discussed in this article. METHODS: Three patients with hereditary hemorrhagic telangiectasia and hepatic involvement received transplants. They had pulmonary hypertension and chronic right-sided heart failure caused by disseminated intrahepatic telangiectasias with shunts between the hepatic artery and hepatic veins or portal vein. Left-to-right intrahepatic shunt output was estimated to range between 51% and 57.5% of cardiac output. RESULTS: Hyperdynamic circulation disappeared after liver transplantation in all patients. Results of computed tomography and right-sided heart catheterization performed 6 months later were normal. Follow-up periods currently are 65, 53, and 29 months, and each patient continues to be asymptomatic. CONCLUSIONS: This report suggests that liver transplantation can be considered as an alternative and successful curative treatment that may prevent the irreversible evolution of cardiopulmonary disease.

Adult↗
PubMed1999

The effects of clonidine on sensitivity to phenylephrine and nitroprusside in patients with essential hypertension recovering from surgery.

UNLABELLED: Clonidine reduces postoperative circulatory instability in patients with essential hypertension. It also increases the sensitivity to vasopressors before and during anesthesia. We investigated blood pressure responses to phenylephrine and nitroprusside pre- vs postoperatively and the effect of clonidine on these responses in patients with essential hypertension. Twenty patients received clonidine 6 microg/kg orally 120 min before anesthesia and 3 microg/kg IV over the final hour of surgery or an identical placebo. During increasing bolus doses of phenylephrine and nitroprusside (30-300 microg), the maximal systolic pressure responses were recorded at baseline on the day before surgery, before the induction of anesthesia, and 1 and 3 h postoperatively. Sensitivity to phenylephrine and nitroprusside was interpolated from linear regression of the data. There was no difference between preoperative and postoperative sensitivity to phenylephrine or nitroprusside in either group. Clonidine increased sensitivity to phenylephrine versus placebo before and after surgery (response to dose of 1.5 microg/kg: 42+/-14 vs 27+/-8 mm Hg preinduction, 37+/-10 vs 26+/-8 mm Hg 3 h postoperatively; both P < 0.01), but not to nitroprusside (38+/-6 vs 37+/-10 mm Hg preinduction and 40+/-6 vs 39+/-8 mm Hg postoperatively). Clonidine increases the sensitivity to phenylephrine but not nitroprusside at baseline and postoperatively in hypertensive patients. IMPLICATIONS: Clonidine increases the sensitivity to bolus injections of the vasoconstrictor phenylephrine, but not the vasodilator sodium nitroprusside, before and after surgery in patients with preexisting hypertension. The doses of vasopressors should be reduced accordingly in hypertensive patients receiving perioperative clonidine.

Aged↗
PubMed1999

Cardiac baroreflex during the postoperative period in patients with hypertension: effect of clonidine.

BACKGROUND: Patients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines the effects of clonidine on postoperative heart rate control in these patients. METHODS: Using a randomized double-blind placebo-controlled design, 20 patients with essential hypertension (systolic pressure >160 mm Hg or diastolic pressure >95 mm Hg for > or =1 yr) were assigned to receive clonidine (or placebo), 6 microg/kg orally 120 min before anesthesia and 3 microg/kg intravenously over 60 min before the end of surgery. The spontaneous baroreflex ("sequence") technique and analysis of heart rate variability were used to quantify control of heart rate at baseline, before induction of anesthesia, and 1 and 3 h postoperatively. RESULTS: Baroreflex slope and heart rate variability were reduced postoperatively in patients given placebo but not those given clonidine. Clonidine resulted in greater postoperative baroreflex slope and power at all frequency ranges compared with placebo (4.9+/-2.9 vs. 2.2+/-2.1 ms/mm Hg for baroreflex slope, 354+/-685 vs. 30+/-37 ms2/Hz for high frequency variability). Clonidine also resulted in lower concentrations of catecholamine, decreased mean heart rate and blood pressure, and decreased perioperative tachycardia and hypertension. CONCLUSIONS: Patients with hypertension exhibit reduced heart rate control during the recovery period after elective surgery. Clonidine prevents this reduction in heart rate control. This may represent a basis for the improved circulatory stability seen with perioperative administration of clonidine.

Analgesics↗
PubMed1998

Reversal of early acute rejection with increased doses of tacrolimus in liver transplantation: a pilot study.

BACKGROUND: In this pilot study, we present the results of treatment of early (3 months after liver transplantation) acute rejection episodes by increasing only the tacrolimus doses. METHODS: Ten patients who received tacrolimus as primary treatment experienced acute mild (one case), moderate (four cases), or severe (five cases) rejection episodes. Tacrolimus dosing was increased 1-2 mg every 1 or 2 days until hepatic enzymes started to improve. Steroid basic daily doses were kept unchanged. RESULTS: With the daily dose of tacrolimus increased by a median 1.89-fold (range: 1.2-5), alanine aminotransferase, bilirubin, and gamma-glutamyltranspeptidase levels rapidly reached normal values within the first month. During a median follow-up time of 19.5 months (range: 14-24), none of the 10 patients died or lost their graft. Control liver biopsies were done 13.5 months (range: 7-19) after rejection episode in all patients, and none demonstrated evidence of rejection or sequela. CONCLUSION: This pilot study suggests that increasing tacrolimus dosage could be considered as treatment against early acute rejection episodes including the severe grade.

Acute Disease↗
PubMed1998

Catechol activation in the vasomotor center upon emergence from anesthesia: specificity.

The rostral ventrolateral medulla (RVLM) controls the vascular system. It may contribute to postoperative hypertension observed upon emergence from anesthesia. This structure contains adrenergic cardiovascular neurons. Therefore, one question was addressed: does a change in RVLM catechol activity occur upon emergence from anesthesia? Halothane-anesthetized, paralyzed rats had their ventilatory, circulatory, and acid-base stability controlled. All pressure points and incisions were infiltrated with local anesthetic. With in vivo electrochemistry, a catechol signal was recorded in the RVLM in the following circumstances: (1) under stable halothane anesthesia for 120 minutes (halothane group), (2) during 120 minutes after halothane discontinuation (saline-emergence group), (3) during 60 minutes after halothane discontinuation followed by 60 minutes after halothane readministration (readministration group), (4) emergence in rats treated with atenolol and nitroprusside to hold blood pressure as close as possible to baseline, (5) emergence after morphine 1 mg.kg(-1) i.v., (6) emergence after decerebration, and (7) emergence upon recording in the mid-brain dopaminergic A10 area. Stable halothane anesthesia (n = 6) led to no change in mean arterial pressure (MAP), heart rate (HR), and catechol signal (CAOC). During emergence from anesthesia (n = 6), MAP, HR, and catechol signal increased and did not return to baseline. By contrast, a return of MAP, HR, and catechol signal to baseline was observed upon readministration of halothane (n = 6). Whereas blood pressure and heart rate were maintained as closely as possible to baseline, a large catechol activation (n = 5) was observed upon emergence from anesthesia. A catechol activation from a lowered baseline was observed upon emergence following morphine administration (n = 5). A minor circulatory activation without RVLM catechol activation was observed upon emergence following decerebration (n = 5). Recordings in the A10 area revealed no increase in the catechol signal following emergence (n = 5). Adrenergic RVLM neurons appear to be responsive upon emergence from anesthesia, possibly being activated by suprapontine afferents impinging on the RVLM.

Adrenergic beta-Antagonists↗
PubMed1998

Left ventricular loading modifications induced by pneumoperitoneum: a time course echocardiographic study.

UNLABELLED: The intraperitoneal insufflation of carbon dioxide during laparoscopic procedures is associated with an increase in mean arterial pressure and systemic vascular resistance. To evaluate the time course of the circulatory changes related to intraabdominal pressure variation, we used transesophageal echocardiography in 10 patients anesthetized for laparoscopic cholecystectomy. Left ventricular dimensions, fractional area shortening (FAS), and left ventricular afterload assessed by the left ventricular end-systolic wall stress (LVESWS) were measured from echocardiographic data before insufflation, during pneumoperitoneum, and during exsufflation. Three minutes after the onset of pneumoperitoneum, we observed a 25.7% +/- 10.5% (mean +/- SD) increase in mean arterial pressure, a 49.1% +/- 14.4% increase in LVESWS, and a 17.0% +/- 16.2% decrease in FAS. All measured variables returned to preinsufflation values after 30 min of pneumoperitoneum and thereafter were no longer significantly affected by postural changes (10 degrees head-up position) or pneumoperitoneum exsufflation. We conclude that the circulatory changes associated with pneumoperitoneum are transient and are probably mediated by factors other than intraabdominal pressure variations. IMPLICATIONS: Insufflation of gas into the abdominal cavity results in hemodynamic changes during laparoscopic procedures. We found that echocardiographic and blood pressure effects associated with gas insufflation were transient, indicating mediation by factors besides intraabdominal pressure.

Adult↗
PubMed1998

Time course evolution of ventilatory responses to inspiratory unloading in patients.

Inspiratory muscle unloading decreases ventilatory drive. In this study, we examined the time course of this effect in patients with chronic obstructive pulmonary disease receiving two modes of ventilatory support: pressure support ventilation (PSV), during which each cycle was assisted, and biphasic positive airway pressure (BIPAP), set up in such a manner that one spontaneous breath took place between two consecutive pressure-assisted breaths. The first breath following the switch from spontaneous breathing to PSV was associated with an increase in tidal volume (VT) and a drop in mean transdiaphragmatic pressure (mean Pdi) and inspiratory work (WI) performed per liter but with unchanged values of esophageal occlusion pressure at 100 ms (Pes 0.1), diaphragmatic electrical activity (EMGdi), and WI performed by breath. The same phenomena were observed for the assisted breath of BIPAP as compared with the preceding spontaneous breath. During the subsequent breaths of PSV, Pes 0.1, EMGdi, and WI performed per breath decreased progressively up to the sixth to eighth breaths, and VT returned to pre-PSV values. We conclude that in patients with chronic obstructive pulmonary disease the decrease in ventilatory drive associated with PSV takes place from the first breath onwards but requires six to eight breaths to be fully achieved. During BIPAP, as a consequence of the kinetics of the PSV-induced downregulation of ventilatory drive, assisted breaths following spontaneous breaths are characterized by an enhanced inspiratory efficiency.

Aged↗