Biomedical subjects

J Duranteau

Publications and source records attributed to J Duranteau.

At least 19 recordsLinked to original sources

PubMed2000

[Impact of an information booklet on patient satisfaction in anesthesia].

OBJECTIVE: The aim of this study was to evaluate the satisfaction of adult surgical patients before and after an information booklet concerning anaesthetic techniques and complications, and postoperative management has been proposed during preanaesthetic visits. STUDY DESIGN: Survey. METHOD: Three surveys have been performed using an anonymous questionnaire of 25 items with graduated answers (very good, good, bad, very bad, no opinion) concerning patient satisfaction on structure, physician behavior, information and well being. As the results of the first two surveys were not significantly different, an information booklet was proposed to patients during preanaesthetic visits, then a third survey ("After") was realized. The results of this survey were compared to the combined results of the first two surveys ("Before"). RESULTS: In the "before" survey, 60 to 76% of the patients were satisfied (very good and good) of the information delivered during preanaesthetic visits. The proportion of patients satisfied of the information concerning anaesthetic techniques, transfusion and recovery were significantly higher in the "after" survey (P < 0.05). CONCLUSION: An information booklet on anaesthesia increases patient satisfaction on information provided during preanaesthetic visits.

Adult↗

PubMed1999

Effects of epinephrine, norepinephrine, or the combination of norepinephrine and dobutamine on gastric mucosa in septic shock.

OBJECTIVES: To compare in the same patient with septic shock, respective effects of epinephrine, norepinephrine, and the combination of norepinephrine and dobutamine (5 microg/kg/min) on systemic hemodynamic parameters and gastric mucosal perfusion using gastric tonometry and laser-Doppler flowmetry techniques. DESIGN: Prospective, controlled, randomized, crossover study. SETTING: University hospital intensive care unit. PATIENTS: Twelve patients with septic shock. INTERVENTIONS: Each patient received in a random succession epinephrine, norepinephrine, and norepinephrine plus dobutamine. Dosages of epinephrine and norepinephrine were adjusted to achieve a mean arterial pressure between 70 and 80 mm Hg. A laser-Doppler probe and a tonometer were introduced into the gastric lumen. MEASUREMENTS AND MAIN RESULTS: The increase in gastric mucosal perfusion detected by laser-Doppler flowmetry was higher with epinephrine and the combination of norepinephrine and dobutamine than with norepinephrine alone (p < .05). In addition, the ratio of gastric mucosal perfusion (local oxygen delivery) to systemic oxygen delivery was increased after norepinephrine plus dobutamine as compared with norepinephrine alone and epinephrine (p< .05). Although values of intramucosal pH and gastroarterial PCO2 tended to be higher with norepinephrine plus dobutamine compared with those obtained with norepinephrine and epinephrine, differences were not statistically significant. CONCLUSIONS: For the same mean arterial pressure in patients with septic shock, our study showed that administration of epinephrine increased gastric mucosal perfusion more than norepinephrine administration alone. Addition of dobutamine (5 microg/kg/ min) to norepinephrine improved gastric mucosal perfusion. This result could be explained by a vasodilating effect of dobutamine on gastric mucosal microcirculation.

Adrenergic beta-Agonists↗

PubMed1998

Intracellular signaling by reactive oxygen species during hypoxia in cardiomyocytes.

Cardiomyocytes suppress contraction and O2 consumption during hypoxia. Cytochrome oxidase undergoes a decrease in Vmax during hypoxia, which could alter mitochondrial redox and increase generation of reactive oxygen species (ROS). We therefore tested whether ROS generated by mitochondria act as second messengers in the signaling pathway linking the detection of O2 with the functional response. Contracting cardiomyocytes were superfused under controlled O2 conditions while fluorescence imaging of 2, 7-dichlorofluorescein (DCF) was used to assess ROS generation. Compared with normoxia (PO2 approximately 107 torr, 15% O2), graded increases in DCF fluorescence were seen during hypoxia, with responses at PO2 = 7 torr > 20 torr > 35 torr. The antioxidants 2-mercaptopropionyl glycine and 1,10-phenanthroline attenuated these increases and abolished the inhibition of contraction. Superfusion of normoxic cells with H2O2 (25 microM) for >60 min mimicked the effects of hypoxia by eliciting decreases in contraction that were reversible after washout of H2O2. To test the role of cytochrome oxidase, sodium azide (0.75-2 microM) was added during normoxia to reduce the Vmax of the enzyme. Azide produced graded increases in ROS signaling, accompanied by graded decreases in contraction that were reversible. These results demonstrate that mitochondria respond to graded hypoxia by increasing the generation of ROS and suggest that cytochrome oxidase may contribute to this O2 sensing.

Animals↗

PubMed1998

Hibernation during hypoxia in cardiomyocytes. Role of mitochondria as the O2 sensor.

During myocardial hibernation, decreases in coronary perfusion elicit inhibition of contraction, suggesting that energy demand is attenuated. We previously found an inhibition of contraction and O2 consumption during hypoxia (3% O2; PO2 = 20 torr for >2 h) in cardiomyocytes, which was reversible after reoxygenation. This study sought to determine whether mitochondria function as cellular O2 sensors mediating this response. Embryonic cardiomyocytes were studied under controlled O2 conditions. Hypoxia produced no acute decrease in mitochondrial potential as assessed using tetramethylrhodamine ethylester (TMRE). Cellular [ATP] was preserved throughout hypoxia, as assessed using the probe Magnesium Green. Thus, ATP synthesis and utilization remained closely coupled. Cells adapted to hypoxia for >2 h exhibited a 4% increase in mitochondrial potential upon reoxygenation, suggesting that a partial inhibition of cytochrome c oxidase had existed. To test whether the oxidase serves as an O2 sensor, azide was administered (1 mM) to simulate the effects of hypoxia by lowering the Vmax of the oxidase. The effects of azide on contraction and mitochondrial potential mimicked the response to hypoxia. We conclude that partial inhibition of cytochrome oxidase during hypoxia allows mitochondria to function as the O2 sensor mediating the decreases in ATP utilization and O2 consumption during hypoxia.

Adenosine Triphosphate↗

PubMed1998

Cardiac output during liver transplantation.

PURPOSE: Measurement of cardiac output is an essential part of anaesthetic practice in patients undergoing major operative procedures. A thermodilution technique, using a pulmonary artery catheter is currently accepted as the gold standard in clinical practice. However its use is associated with several limitations. METHOD: In this prospective randomised controlled study measurement of cardiac output, an oesophageal Doppler monitor (ODM) was compared with the thermodilution technique in 18 patients undergoing orthotopic liver transplantation. Measurements were taken during the three phases of liver transplantation, i) dissection phase (three measurements), ii) anhepatic phase (four) and iii) reperfusion phase (six). RESULTS: There were no differences observed between the two measurements at any of the times studied and a strong correlation was observed (r = 0.714; P < 0.00001). However, when the data was analysed using Bland and Altman analysis, while the mean difference was small (0.07 l.min-1) it was > 2 l.min-1 in one third of measurements recorded i.e., the bias was near zero but the precision was large. No consistent differences were seen using the two methods in individual patients. CONCLUSION: The use of the ODM results in cardiac output measurements which are considerably different from those obtained using thermodilution and its use cannot be recommended in patients undergoing orthotopic liver transplantation.

Adult↗

PubMed1998

Gastric mucosal oxygen delivery decreases during cardiopulmonary bypass despite constant systemic oxygen delivery.

UNLABELLED: Previous studies report a decrease in gastric mucosal oxygen delivery during cardiopulmonary bypass (CPB). However, in these studies, CPB was associated with a reduction in systemic oxygen delivery (DO2). Conceivably, this decrease in DO2 could have contributed to the observed decrease in gastric mucosal oxygen delivery. Thus, in the present study, we assessed the effects of the maintenance of DO2 (at pre-CPB values) during hypothermic (30-32 degrees C) CPB on the gastric mucosal red blood cell flux (GMRBC flux) using laser Doppler flowmetry. In 11 patients requiring cardiac surgery, the pump flow rate during CPB was initially set at 2.4 L x min(-1) x m(-2) and was adjusted to maintain DO2 at pre-CPB values (flow 2.5-2.7 L x min[-1] x m[-2]). Despite a constant DO2, the GMRBC flux was decreased during CPB. These decreases averaged 50% +/- 16% after 10 min, 50% +/- 18% after 20 min, 49% +/- 21% after 30 min, and 49% +/- 19% after 40 min of CPB. The rewarming period was associated with an increase in GMRBC flux. Thus, maintaining systemic DO2 during CPB seems to be an ineffective strategy to improve gastric mucosal oxygen delivery. IMPLICATIONS: In the present study, we tested the hypothesis that gastric mucosal red blood cell flux assessed by laser Doppler flowmetry could be improved by maintaining baseline systemic flow and oxygen delivery during hypothermic cardiopulmonary bypass. Despite this strategy, gastric mucosal red blood cell flux decreased by 50% during hypothermic cardiopulmonary bypass.

Animals↗

PubMed1997

A comparison of propofol with a propofol-ketamine combination for sedation during spinal anesthesia.

Propofol (P) is increasingly used as a sedative during regional anesthesia. Providing titratable sedation and rapid recovery, it can compromise hemodynamic stability. However, in combination with ketamine (K), it provides stable hemodynamics during total intravenous anesthesia, avoiding emergence phenomena. We compared the efficacy, respiratory and hemodynamic profiles, and side effects of these two sedative regimes in patients undergoing spinal anesthesia. Forty patients, ASA physical status I and II, undergoing urologic or orthopedic procedures were randomly assigned to one of two groups (n = 20 each). Group 1 (P + K) received initial doses of 0.4 mg/kg P, 0.1 mg/kg K, followed by an intravenous infusion of 1.2 mg x kg(-1) x h(-1) and 0.3 mg x kg(-1) x h(-1), respectively. Group 2 (P) received bolus 0.5 mg/kg and infusion 1.5 mg x kg(-1) x h(-1). Subsequent infusion rates were titrated to a predetermined sedation level using a 5-point score. Heart rate, arterial pressure, respiratory rate, oxygen saturation end-tidal CO2, and oxygen requirements were recorded. Sedation scores were similar for both groups. There was no difference in total propofol requirements between Group 1 (146 +/- 94 mg) and Group 2 (137 +/- 52 mg) (mean +/- SD). Mean arterial pressure was significantly higher in the P + K group, e.g., 91 mm Hg (86-94) vs 75 mm Hg (69-83) at 30 min (mean +/- SD). Administration of vasopressors and fluids as well as recovery and emergence phenomena were similar between groups. Although the described additive effect of propofol and ketamine was not confirmed, the combination conferred hemodynamic stability during spinal anesthesia.

Adult↗

PubMed1996

Left ventricular function after severe trauma.

OBJECTIVE: To evaluate cardiac function at the early phase of severe trauma. DESIGN: Prospective, clinical study. SETTING: Anesthesiological Intensive Care Unit. PATIENTS: 7 consecutive patients admitted after severe trauma (ISS: 38 +/- 9, mean +/- SD), without preexisting cardiac disease. INTERVENTIONS: Each patient received midazolam and sufentanyl for sedation. Right heart catheterization (Swan-Ganz) and transesophageal echocardiography (TEE) were performed. The fractional area change (FAC) of the left ventricle was calculated within 6 h following trauma and at day 1 and day 2 in order to evaluate left ventricular function. MEASUREMENTS AND RESULTS: All of the patients had a low FAC value < 50% at day 0 (43.2 +/- 2.4%, range 39-46%), which increased significantly at day 2 (52.5 +/- 4%, range 47-59%, p = 0.001), whereas heart rate and preload (assessed by left ventricular end diastolic area and pulmonary arterial occlusion pressure) were constant and afterload, assessed by systolic blood pressure, increased significantly between day 0 and day 2 (112 +/- 21 to 145 +/- 24 mmHg, p = 0.02). CONCLUSION: The initial phase of severe trauma is associated with an abnormal cardiac function, suggested by a low FAC value. This myocardial dysfunction must be taken into account for early resuscitation after severe injury.

Adult↗

PubMed1996

Transgastric, pulsed Doppler echocardiographic determination of cardiac output.

OBJECTIVE: The aim of this study was to evaluate the accuracy of cardiac output measurement with transesophageal echocardiography (TEE) using a transgastric, pulsed Doppler method in acutely ill patients. DESIGN: Cardiac output was simultaneously measured by thermodilution (TD) and a transgastric, pulsed Doppler method. SETTING: The study was carried out in a surgical intensive care unit as part of the management protocol of the patients. PATIENTS: Thirty consecutive acutely ill patients with a Swan-Ganz catheter, mechanically ventilated, sedated and with a stable hemodynamic condition were included. MEASUREMENTS: Pulsed Doppler TEE was performed using a transgastric approach in order to obtain a long axis view of the left ventricle. Cardiac output was calculated from the left ventricular outflow tract diameter, the velocity time integral of the blood flow profile and heart rate. RESULTS: One patient was excluded because of the presence of aortic regurgitation and another, because of the impossibility of obtaining a transgastric view. Twenty-eight simultaneous measurements were performed in 28 patients. A clinically acceptable correlation and agreement were found between the two methods (Doppler cardiac output = 0.889 thermodilution cardiac output +0.74 l/min, r = 0.975, p <0.0001). CONCLUSION: Transgastric pulsed Doppler measurement across the left ventricular outflow tract with TEE is a very feasible and clinically acceptable method for cardiac output measurement in acutely ill patients.

Adult↗

PubMed1996

Assessment of gastric mucosal perfusion during simulated hypovolemia in healthy volunteers.

We described here an original device for laser Doppler (LD) flowmetry measurements of gastric mucosal perfusion, which was used here in healthy volunteers. A modified nasogastric tube containing the LD probe was inserted. Aspiration via a catheter, fixed in parallel to the probe, held the probe against the gastric wall. This new device was used to assess gastric mucosal perfusion in seven volunteers during simulated hypovolemia induced by lower body negative pressure (LBNP) application. The LBNP consisted of three successive levels of depression (-10, -20, and -30 mm Hg). Although mean arterial pressure remained unchanged during negative pressure application, there was a significant decrease in cardiac output (transthoracic electrical impedance) at each stage of LBNP. In contrast, gastric mucosal perfusion decreased significantly only at higher level of sympathetic stimulation corresponding to unloading of both cardiopulmonary and arterial baroreflexes (-30 mm Hg). It may be hypothetized that local vascular mechanisms exist to maintain gastric mucosal perfusion during moderate sympathetic stimulation induced by selective unloading of cardiopulmonary receptors. In the healthy volunteers studied, we found that LD flowmetry is a valuable tool to evaluate gastric mucosal perfusion when the probe is maintained in a constant position by the technique described here.

Adult↗

PubMed1995

Role of systemic inflammatory response syndrome and infection in the occurrence of early multiple organ dysfunction syndrome following severe trauma.

OBJECTIVE: To evaluate the role of infection and systemic inflammatory response syndrome (SIRS) on the occurrence of early posttraumatic MODS. DESIGN: Retrospective study. SETTING: University Teaching Hospital ICU. PATIENTS: 163 consecutive patients hospitalized for more than 48 hours following severe trauma. MEASUREMENTS AND MAIN RESULTS: The patients were classified into two groups in respect to the existence of MODS at day 2. There was 27 patients in the MODS group and 136 patients in the no MODS group. The two groups were similar with respect to age, sex ratio and Simplified Acute Physiology Score. The MODS group had a higher mortality (52 versus 7%), Injury Severity Score (45 +/- 14 versus 31 +/- 13), hypovolemic shock rate (74 versus 30%), massive volume replacement rate (59 versus 6%) and SIRS rate (81 versus 54%) than the no MODS group (P < 0.05). The rate of infection was similarly low in the MODS and no MODS group (4 versus 6% respectively). CONCLUSION: Early MODS is often associated with hypotension and massive volume administration but very rarely with infection, despite the high rate of SIRS.

Adult↗

PubMed1995

Role of the renin-angiotensin system in systemic and regional vascular responses to orthostatic stress in healthy volunteers.

The effects of a single oral dose (5 mg) of the angiotensin-converting enzyme (ACE) inhibitor, ramipril, on the systemic and regional vascular responses to simulated orthostatic stress by the lower body negative pressure (LBNP) technique were investigated in eight healthy volunteers, in a double-blind, placebo-controlled crossover study. Arterial blood pressure remained unchanged throughout the study. Ramipril increased significantly forearm (venous occlusion plethysmography, + 37% +/- 4% from 1.98 ml.min-1.100 ml-1) and renal (PAH clearance, + 6 +/- 2% from 1.20 1.min-1) blood flows and decreased corresponding vascular resistances, 150 minutes after its administration and before LBNP. It also significantly reduced calculated filtration fraction and inhibited by approximately 86% plasma ACE activity. Lower body negative pressure at -10 and -20 mmHg induced a progressive and significant decrease in central venous pressure and significant increases in forearm, splanchnic (indocyanine green clearance) and total peripheral vascular resistances which were of the same magnitude after ramipril and placebo administrations. Ramipril blunted the LBNP-induced increase in renal vascular resistance observed at -20 mmHg after placebo but a similar increase in glomerular filtration rate (inulin clearance) was observed at LBNP-10 and -20 mmHg after ramipril and placebo. Calculated filtration fraction increased after placebo (LBNP-10 mmHg) and ramipril (LBNP-20 mmHg). Finally, LBNP-induced changes in biological parameters were similar after ramipril and placebo at all levels of LBNP. Thus, ramipril does not interfere with the adaptive forearm and splanchnic vascular responses and preserves renal hemodynamics during orthostatic stress simulated by LBNP in healthy volunteers.

Adult↗

PubMed1995

Effects of the angiotensin type I receptor antagonist, losartan, on systemic and regional vascular responses to lower body negative pressure in healthy volunteers.

1. The effects of a single oral dose (50 mg) of the angiotensin II AT1-receptor antagonist, losartan, on the systemic and regional vascular responses to simulated orthostatic stress by the lower body negative pressure (LBNP) technique were investigated in nine healthy volunteers, in a double-blind, placebo-controlled crossover study. 2. Arterial blood pressure remained unchanged throughout the study. Three hours after its administration and before LBNP, losartan selectively increased renal blood flow (PAH clearance) by 8.3% (3.5 to 13.1%, 95% CI) from 1.25 +/- 0.08 l min-1 (P < 0.05) and decreased plasma aldosterone levels by 58% (29 to 87%, 95% CI) from 22 +/- 3 ng 100 ml-1 (P < 0.05). 3. LBNP at -10 and -20 mm Hg induced a progressive and significant decrease in central venous pressure and increases in forearm (plethysmography) and splanchnic (indocyanine green clearance) vascular resistances which were similar after losartan and placebo administrations. Losartan blunted the LBNP-induced increase in renal vascular resistance observed at -20 mm Hg after placebo but a similar increase in glomerular filtration rate (inulin clearance) was observed at LBNP -10 and -20 mm Hg after losartan and placebo. Calculated filtration fraction increased after placebo (LBNP -10 mm Hg) and losartan (LBNP -20 mm Hg). Finally, LBNP-induced changes in biological parameters were similar after losartan and placebo at all levels of LBNP. 4. Thus, losartan does not interfere with the adaptive forearm and splanchnic vascular responses and preserves renal haemodynamics during orthostatic stress simulated by LBNP in healthy volunteers.

Adult↗

PubMed1994

Heterogeneous regional vascular responses to simulated transient hypovolemia in man.

OBJECTIVE: To describe the evolution of systemic and regional blood flows during and after hypovolemia in humans. DESIGN: Simulation of hypovolemia by a prolonged application of lower body negative pressure (LBNP). SETTING: Laboratory of Clinical Research, Surgical Intensive Care Unit of an University Hospital. PARTICIPANTS: 8 healthy male volunteers. INTERVENTIONS: 3 successive and increasing 15 min-levels of LBNP were followed by a progressive return (10 min) to atmospheric pressure, then a 60 min-recovery period. MEASUREMENTS AND MAIN RESULTS: Simulated hypovolemia induced a parallel one-third decrease in cardiac output (bioimpedance), musculocutaneous (venous plethysmography) and splanchnic (ICG clearance) blood flows. Adrenergic-mediated peripheral vasoconstriction prevented any change in mean arterial pressure. The decrease in renal blood flow (PAH clearance) was limited, glomerular filtration rate (inulin clearance) unchanged and thus filtration fraction increased. All the cardiovascular and biological variables returned to pre-LBNP values during the recovery period except for splanchnic blood flow which remained below control values 60 min after the return to atmospheric pressure. CONCLUSIONS: Since a sustained splanchnic vasoconstriction follows a transient normotensive hypovolemia in healthy men despite adequate treatment considering arterial pressure and cardiac output, the therapeutic goals of fluid resuscitation after hypovolemic shock might be revisited and a supranormal value of cardiac output proposed.

Adult↗

PubMed1992

Flosequinan does not affect systemic and regional vascular responses to simulated orthostatic stress in healthy volunteers.

1. The effects of a single oral dose (100 mg) of flosequinan on systemic and regional (forearm, splanchnic and renal) vascular responses to simulated orthostatic stress (lower body negative pressure, LBNP) were investigated in nine healthy male volunteers, in a double-blind, placebo-controlled crossover study. 2. Forty-five minutes after its administration and before LBNP, flosequinan induced a significant decrease in total peripheral and in forearm vascular resistances without any concomitant change in arterial pressure, in heart rate and in the investigated biological parameters (plasma catecholamines, arginine vasopressin and renin activity). 3. After flosequinan and placebo, LBNP induced similar decreases in central venous pressure at all levels of LBNP (-10, -20 and -40 mm Hg) and in pulse pressure at LBNP -40 mm Hg. LBNP-induced increase in forearm vascular resistance was significantly more marked after flosequinan than after placebo at all levels of LBNP, and this was also true for splanchnic vascular resistance but at LBNP -40 mm Hg only. However, inasmuch as the basal values of these two parameters before LBNP were lower after flosequinan than after placebo, their final values after LBNP -40 mm Hg were similar. Finally, LBNP-induced changes in renal vascular resistance, glomerular filtration rate and filtration fraction as well as in plasma catecholamines, arginine vasopressin and renin activity were similar after flosequinan and placebo at all levels of LBNP. 4. Flosequinan affected neither reflex control of heart rate (phenylephrine test) nor non-specific vasoconstrictor responses (cold pressor test). (ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1992

Baroreflex control of regional vascular resistances during simulated orthostatism.

Orthostatic stress or moderate hypovolemia was simulated in 10 healthy volunteers by the lower body negative pressure technique (LBNP at -10, -20 and -40 mm Hg). LBNP induced a progressive and parallel decrease in central venous pressure and cardiac output but mean arterial pressure remained unchanged regardless of the LBNP level. Heart rate and pulse pressure were only significantly increased and decreased at LBNP -40 mm Hg, respectively, indicating that cardiopulmonary baroreflexes were selectively deactivated up to LBNP -20 mm Hg, whereas both cardiopulmonary and arterial baroreflexes were deactivated at LBNP -40 mm Hg. The LBNP-induced increase in total peripheral resistance was heterogeneously distributed within the body. Forearm vasoconstriction occurred at low levels of LBNP and was exclusively related to an increase in sympathetic tone. Splanchnic vasoconstriction also occurred at low levels of LBNP, but was related to activation in sympathetic and renin-angiotensin systems. Renal vasoconstriction occurred mainly at high levels of LBNP (-40 mm Hg), but glomerular filtration rate and filtration fraction increased at low levels of LBNP (-10 mm Hg). Thus, if renal vascular resistance is not of major importance for the control of blood pressure during orthostatism or moderate hypovolemia, neurohumoral mechanisms triggered through deactivation of cardiopulmonary receptors play a key role in the maintenance of intrarenal homeostasis associated with reduction in cardiac filling pressure.

Adult↗

PubMed1991

[Effects of lidocaine on arterial and venous circulation of limbs in man].

The effects of intravenous lidocaine on limb arteries and veins were investigated in a placebo-controlled study. Seven young healthy volunteers, 23 to 28-years-old, were included. Electrocardiogram, arterial pressure and arm and leg blood flows were recorded continuously. Systolic and diastolic blood pressures were measured in the left arm by finger photoplethysmography. Limb blood flow and the limb venous system were studied by venous occlusive plethysmography. The venous parameters studied were venous tone, lowest closing pressure, venous volume at 30 mmHg, and venous distensibility. After an initial bolus of 1.5 mg.kg-1 lidocaine had been given, 30, and then 60, micrograms.kg-1.min-1 were given for one hour each. Plasma noradrenaline and serum lidocaine titres were measured before giving the lidocaine, and at the end of each one hour period. Placebo consisted in a two hour infusion of 0.25 ml.min-1 normal saline. Lidocaine titres were 1.64 +/- 0.40 microgram.ml-1 after one hour, and 2.55 +/- 0.69 microgram.ml-1 after two hours. Lidocaine increased vascular resistances in both the forearm (+81% to +93%) and the calf (+38% to +57%). There was a concomitant increase in mean arterial blood pressure (+21% to +28%) without any change in heart rate. There was a significant dose-dependent increase in plasma noradrenaline levels during the second period of the lidocaine infusion with respect to the preinfusion period and the same period during the placebo infusion. Venous capacitance measured before any infusion had been started was greater in the leg than in the arm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Lidocaine and cardiovascular reflex responses to simulated orthostatic stress in normal volunteers.

The interactions of lidocaine with baroreceptor reflexes during simulated orthostatic stress or moderate volume depletion were investigated in healthy volunteers using the lower body negative pressure (LBNP) test. Cardiopulmonary baroreceptors were selectively unloaded at low levels of LBNP (-15 mm Hg) since the central venous pressure (CVP) decreased (-1.4 +/- 0.3 mm Hg) without changes in arterial pressure (AP) and heart rate (HR) but significant increases in forearm vascular resistance (FVR) and plasma noradrenaline (PNA). Cardiopulmonary as well as arterial baroreflexes were both unloaded at higher levels of LBNP (-40 mm Hg) since the CVP (-3.4 +/- 0.4 mm Hg) and systolic AP (-10 +/- 3 mm Hg) decreased whereas FVR, PNA, and plasma renin activity (PRA) increased further (all p less than 0.05). Following lidocaine infusion (serum level of 3.8 +/- 0.2 micrograms/ml), the AP, HR, FVR, and PNA increased and CVP decreased (p less than 0.05). Compared to LBNP performed under saline, lidocaine did not alter the LBNP (-15 mm Hg)-induced changes in cardiovascular and biological parameters but significantly decreased the induced rises in HR, FVR, PNA, and PRA at a LBNP of -40 mm Hg (p less than 0.05). In an additional study, it was also demonstrated that lidocaine significantly decreased the sensitivity of the reflex-mediated bradycardia following phenylephrine injection and attenuated the vasoconstrictor response to the cold pressor test taken as a nonspecific somatic pressor reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗