Biomedical subjects

M Seeberger

Publications and source records attributed to M Seeberger.

11 recordsLinked to original sources

PubMed2006

Effects of sevoflurane and propofol on left ventricular diastolic function in patients with pre-existing diastolic dysfunction.

BACKGROUND: The effects of anaesthetics on left ventricular (LV) diastolic function in patients with pre-existing diastolic dysfunction are not well known. We hypothesized that propofol but not sevoflurane will worsen the pre-existing LV diastolic dysfunction. METHODS: Of 24 randomized patients, 23 fulfilled the predefined echocardiographic criterion for diastolic dysfunction. They received general anaesthesia with sevoflurane 1 MAC (n=12) or propofol 4 mug ml(-1) (n=11). Echocardiographic examinations were performed at baseline and in anaesthetized patients under spontaneous breathing and under positive pressure ventilation. Analysis focused on peak early diastolic velocity of the mitral annulus (E(a)). RESULTS: During spontaneous breathing, E(a) was higher in the sevoflurane than in the propofol group [mean (95% CI) 7.0 (5.9-8.1) vs 5.5 (4.7-6.3) cm s(-1); P<0.05], reflecting an increase of E(a) from baseline only in the sevoflurane group (P<0.01). Haemodynamic findings were similar in both groups, but the end-tidal carbon dioxide content was more elevated in the propofol group (P<0.01). During positive pressure ventilation, E(a) was similarly low in the sevoflurane and propofol groups [5.3 (4.2-6.3) and 4.4 (3.6-5.2) cm s(-1), respectively]. CONCLUSIONS: During spontaneous breathing, early diastolic function improved in the sevoflurane but not in the propofol group. However, during positive pressure ventilation and balanced anaesthesia, there was no evidence of different effects caused by the two anaesthetics.

Adult↗

PubMed2006

Effects of dopexamine in a rat model of supracoeliac aortic cross-clamping and declamping.

This experimental study in rats was designed to demonstrate effects of dopexamine (3 microg kg(-1) min(-1), n = 6) or physiologic saline solution (n = 6) on systemic as well as regional perfusion during 30 min of supracoeliac aortic cross-clamping and during 180 min of reperfusion following declamping. Rats were surgically instrumented with arterial, right atrial and portal venous catheters, ultrasonic flow probes around the abdominal aorta, superior mesenteric and carotid artery, and a paediatric tonometer for intestinal mucosal PCO(2) measurement. During 120 min of reperfusion, fluid resuscitation was titrated to keep abdominal aortic blood flow above 80% of baseline values. We found that during cross-clamping, values of arterial lactate (p = 0.002) and intestinal tonometric PCO(2) (p = 0.018) were higher in the dopexamine group than in the control group.

Animals↗

PubMed2003

Use of myocardial tissue Doppler imaging for intraoperative monitoring of left ventricular function.

BACKGROUND: Detection of myocardial ischaemia during surgery is usually by assessment of regional wall motion using two-dimensional transoesophageal echocardiography (TOE). Tissue Doppler imaging (TDI) may assist this assessment and improve its accuracy. METHODS: We measured peak myocardial velocities in the anterior mid-wall of the left ventricle by TOE and pulsed-wave TDI in addition to transmitral flow velocity, two-dimensional echocardiography and cardiovascular variables. We studied 42 patients before and after coronary bypass surgery with left internal mammary artery grafts. RESULTS: Peak systolic and early and late diastolic velocity measurements of the anterior mid-wall were obtained in all patients. Variation between and within observers was small (<6%). Peak systolic thickening velocity correlated with visual assessment of anterior wall motion score, fractional area change of the left ventricle and left ventricular systolic wall stress. Because of the wide overlap of systolic velocity between the segments with normal and abnormal wall motion, it was not possible to separate normal from abnormal segments on the basis of TDI-derived velocity alone. The diastolic velocity in the anterior wall reflected the transmitral filling pattern. After surgery, the peak systolic and late diastolic anterior wall velocities increased (from 4.2 (95% confidence interval 4.0, 4.7) to 5.7 (4.8, 6.3) cm s(-1) and from 3.5 (3.2, 3.9) to 6.0 (5.1, 6.9) cm s(-1) respectively), while the ratio of early to late diastolic velocity decreased from 1.5 (1.2, 1.7) to 1.0 (0.8, 1.2). TDI changes characteristic of new myocardial ischaemia were not seen in any patient. CONCLUSION: Intraoperative measurement of TDI in the anterior wall of the left ventricle is feasible and provides additional quantitative information on both regional and global systolic and diastolic function. We found changes in myocardial velocities indicating improvement in the systolic and impairment in the diastolic function of the anterior wall of the left ventricle immediately after mammary artery grafting.

Aged↗

PubMed2001

Reference values for left ventricular function in subjects under general anaesthesia and controlled ventilation assessed by two-dimensional transoesophageal echocardiography.

BACKGROUND AND OBJECTIVE: Transoesophageal echocardiography is increasingly used for evaluation and monitoring of left ventricular function in anaesthetized patients. However, the only available reference values for transoesophageal echocardiography were derived from studies in awake subjects. METHODS: We determined left ventricular dimensions and systolic function in 45 patients without clinical evidence of heart disease who voluntarily underwent transesophageal echocardiography under conditions of balanced general anaesthesia, controlled fluid administration, supine position, muscle relaxation and controlled ventilation. RESULTS: The left ventricular dimensions obtained during these conditions were lower than the published normal values in awake subjects. The indices of global left ventricular function, however, were similar to the normal values obtained by either awake transesophageal echocardiography or transthoracic echocardiography. CONCLUSION: We propose using the values obtained in our study as reference values for evaluation of left ventricular function in patients under general anaesthesia and controlled ventilation.

Adult↗

PubMed1999

Systemic and mesenteric hemodynamics, metabolism, and intestinal tonometry in a rat model of supraceliac aortic cross-clamping and declamping.

OBJECTIVE: To describe systemic and mesenteric hemodynamics, metabolism, and intestinal tonometry in a rat model of supraceliac aortic cross-clamping and declamping. DESIGN: Prospective, randomized, experimental study. SETTING: University cardiovascular research laboratory. PARTICIPANTS: Twelve male anesthetized and ventilated Sprague-Dawley rats. INTERVENTION: Supraceliac aortic cross-clamping was performed for 30 minutes, followed by declamping and reperfusion for 180 minutes or sham clamping and sham declamping. MEASUREMENTS AND MAIN RESULTS: Mean arterial blood pressure; abdominal aortic, superior mesenteric, and carotid artery blood flow; intestinal mucosal tonometry; hemoglobin; lactate; and blood gases were measured before and after 30 minutes of aortic cross-clamping and 15, 30, 60, 120, and 180 minutes after declamping during reperfusion. Aortic cross-clamping induced an increase in mean arterial pressure (117+/-20 mm Hg to 147+/-12 mm Hg), an increase in right atrial hemoglobin saturation(66%+/-11% to 81%+/-6%), an increase in lactate levels (1.7+/-0.7 mmol/L to 4.3+/-1.3 mmol/L), and an increase in tonometric PCO2 (49.6+/-5.0 mm Hg to 75.6+/-8.6 mm Hg). Three hours of reperfusion after declamping resulted in significantly decreased mean arterial pressure (38+/-10 mm Hg); decreased aortic (101+/-12 mL/min/kg to 57+/-32 mL/min/kg), mesenteric (19+/-4 to 13+/-6 mL/min/kg), and carotid (12+/-4 mL/min/kg to 5+/-3 mL/min/ kg) blood flows; and elevated lactate levels (4.2+/-2.0 mmol/L). Tonometric PCO2 had normalized to baseline levels (51.9+/-3.8 mm Hg), but PCO2 gap was significantly higher than in sham clamped rats (17.9+/-7.8 mm Hg v. 7.0+/-2.6 mm Hg). CONCLUSIONS: Hemodynamic and metabolic effects of aortic cross-clamping and declamping known from large animal models are reproducible using a rat model. Intestinal tonometry indicated mesenteric ischemia during aortic cross-clamping, which was reversible to preclamp values within 30 minutes of reperfusion after declamping.

Animals↗

PubMed1999

[Perioperative management of patients with arterial hypertension].

Concomitant arterial hypertension in surgical patients is an indicator of increased risk for peri-operative cardiovascular complications. This review article discusses reasons for the increased risk and gives recommendations for the perioperative management of patients with arterial hypertension. In patients with established anti-hypertensive therapy, it is of greatest importance to continue this therapy perioperatively. In addition, the management of patients with preoperatively elevated arterial blood pressure is addressed, and recommendations are provided as to when it seems safe to go on with surgery and when prudent to delay surgery to control hypertension.

Antihypertensive Agents↗

PubMed1999

Immediate effects of mitral valve replacement on left ventricular function and its determinants.

Patients undergoing mitral valve surgery are at risk of left ventricular failure in the immediate post-operative period. In order to understand better the mechanisms of post-operative haemodynamic instability, we used transoesophageal echocardiography to assess the immediate response of the left ventricle to mitral valve replacement for mitral regurgitation or stenosis. A decrease in left ventricular preload, despite adequate filling pressures, was common to both groups and suggests the presence of diastolic dysfunction. A marked impairment in global systolic pump function was observed only in the regurgitation group and correlated with the left ventricular afterload. Transoesophageal echocardiography provides valuable information on the individual changes in left ventricular function and its determinants after mitral valve replacement that are not reflected by haemodynamic measurements.

Anesthesia, General↗

PubMed1999

Immediate effects of aortic valve replacement on left ventricular function and its determinants.

Replacement of the aortic valve exposes the left ventricle to myocardial ischaemia and imposes on it abrupt changes in loading conditions and geometry. We studied the immediate changes in the left ventricular function of patients undergoing aortic valve replacement by transoesophageal echocardiography. Patients with aortic regurgitation responded to surgery with a decrease in global systolic function associated with a fall in preload. Patients with aortic stenosis showed an impairment in myocardial contractility and ventricular filling, and their global systolic function did not improve despite the marked reduction in afterload. This can be a consequence of inadequate myocardial protection and intra-operative ischaemic injury of the hypertrophic myocardium. Information provided by transoesophageal echocardiography contributes to optimal and individualized management of the period immediately after aortic valve replacement.

Aortic Valve↗

PubMed1998

Transient neurologic symptoms after spinal anesthesia: a lower incidence with prilocaine and bupivacaine than with lidocaine.

BACKGROUND: Recent evidence suggests that transient neurologic symptoms (TNSs) frequently follow lidocaine spinal anesthesia but are infrequent with bupivacaine. However, identification of a short-acting local anesthetic to substitute for lidocaine for brief surgical procedures remains an important goal. Prilocaine is an amide local anesthetic with a duration of action similar to that of lidocaine. Accordingly, the present, prospective double-blind study compares prilocaine with lidocaine and bupivacaine with respect to duration of action and relative risk of TNSs. METHODS: Ninety patients classified as American Society of Anesthesiologists physical status I or II who were scheduled for short gynecologic procedures under spinal anesthesia were randomly allocated to receive 2.5 ml 2% lidocaine in 7.5% glucose, 2% prilocaine in 7.5% glucose, or 0.5% bupivacaine in 7.5% glucose. All solutions were provided in blinded vials by the hospital pharmacy. Details of spinal puncture, extension and regression of spinal block, and the times to reach discharge criteria were noted. In the evening of postoperative day 1, patients were evaluated for TNSs by a physician unaware of the drug administered and the details of the anesthetic procedure. RESULTS: Nine of 30 patients receiving lidocaine experienced TNSs, 1 of 30 patients receiving prilocaine (P = 0.03) had them, and none of 30 patients receiving bupivacaine had TNSs. Times to ambulate and to void were similar after lidocaine and prilocaine (150 vs. 165 min and 238 vs. 253 min, respectively) but prolonged after bupivacaine (200 and 299 min, respectively; P < 0.05). CONCLUSIONS: Prilocaine may be preferable to lidocaine for short surgical procedures because it has a similar duration of action but a lower incidence of TNSs.

Adult↗

PubMed1996

Extradural abscess complicating lumbar extradural anaesthesia and analgesia in an obstetric patient.

A 33-year-old nulliparous woman with severe pre-eclampsia was treated with extradural analgesia to control blood pressure and relieve pain during delivery. Nine hours after extradural catheter insertion a Caesarean section was performed due to uterine inertia. The extradural catheter was kept in place for 88 hours. Ten days following the extradural block she developed an extradural abscess and had to undergo a laminectomy. In a retrospective and, in part, prospective analysis on more than 13,000 extradural blocks, we studied the incidence of this dreaded complication and reviewed the literature on clinical findings, diagnosis and treatment.

Abscess↗

PubMed1985

Pharmacokinetics of 3 prednisolone prodrugs. Evidence of therapeutic inequivalence in renal transplant patients with rejection.

Renal allograft rejections are often treated with high doses of prednisone or prednisolone. The solubility of the biologically active prednisolone is poor. Therefore prednisolone is given i.v. as prednisolone disodium phosphate (prednisolone phosphate) or as prednisolone sodium tetrahydrophthalate (prednisolone phthalate). The time course of hydrolysis of high doses of these prodrugs and the reduction of high doses of oral prednisone into prednisolone has not been investigated. Therefore 10 patients treated for acute rejection were given, on 3 occasions, oral prednisone, i.v. prednisolone phosphate, or i.v. prednisolone phthalate in equimolar doses corresponding to 7 mg/kg of prednisolone. Blood samples were collected over a 24-hr period. Measurements were performed by high-performance liquid chromatography and equilibrium dialysis. The time to peak, the peak concentrations, and the area under the plasma-concentration-vs.-time curve (AUC) of prednisone and of unbound prednisolone were calculated. In all patients the hydrolysis of the prednisolone phosphate ester was faster than that of the prednisolone phthalate ester. The mean (+/- SD) peak concentrations of unbound prednisolone were higher after i.v. prednisolone phosphate (18.5 +/- 3.4 micrograms/ml) than after i.v. prednisolone phthalate (2.9 +/- 0.5 micrograms/ml) or after oral prednisone (3.1 +/- 0.8 micrograms/ml), (P less than 0.001). The mean AUCs of unbound prednisolone were 2324 +/- 683 micrograms/ml/min from prednisolone phosphate, 1209 +/- 324 micrograms/ml/min from prednisolone phthalate, and 1584 +/- 556 micrograms/ml/min from oral prednisone. The AUCs of prednisolone from i.v. prednisolone phosphate (P less than 0.001) or from oral prednisone (P less than 0.005) were higher than from i.v. prednisolone phthalate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗