Biomedical subjects

Berthold Bein

Publications and source records attributed to Berthold Bein.

23 records · Page 2Linked to original sources

PubMed2005

Comparison of two bispectral index algorithms in monitoring sedation in postoperative intensive care patients.

OBJECTIVE: Comparison of two versions of bispectral index (BIS) derived from the electroencephalogram in mechanically ventilated and continuously sedated patients after major abdominal surgery. DESIGN: Prospective, cohort, observational, unblinded study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: Forty-six patients undergoing major abdominal surgery scheduled for postoperative mechanical ventilation and continuous sedation. INTERVENTIONS: Patients were continuously sedated using propofol and sufentanil. MEASUREMENTS AND MAIN RESULTS: Electrodes for determination of BIS were placed at the forehead of the patients according to the manufacturer's specifications immediately after arrival to the intensive care unit. The level of consciousness was assessed every 2 hrs by a clinical sedation scale (Ramsay sedation scale, levels 1-6). BIS, electromyographic activity, and signal quality index were recorded simultaneously at the same time as the Ramsay scale for 24 hrs or until patients were ready for extubation. BIS (version 2.10) and BIS XP (version 3.12) were determined at 2-hr intervals. BIS and BIS XP showed a high correlation of readings (rs = .79, p < .01). However, the methods did not yield identical results. Both variables were significantly influenced by electromyographic activity, especially at high values, whereas there was only a weak correlation with body temperature. Some of the deeply sedated patients (Ramsay 5 or 6) had BIS readings >80 (BIS, 16%; BIS XP, 13%; p = not significant). CONCLUSIONS: The newer algorithm BIS XP did not perform better than the previous version BIS in patients after major surgery who were mechanically ventilated and sedated on an intensive care unit. This precludes the use of BIS or BIS XP for distinguishing, among deeply sedated ICU patients, those with and without preserved cerebral electrical activity.

Algorithms↗

PubMed2005

The effect of meperidine on thermoregulation in mice: involvement of alpha2-adrenoceptors.

Meperidine has potent antishivering properties. The underlying mechanisms are not fully elucidated, but recent investigations suggest that alpha2-adrenoceptors are likely to be involved. We performed the current study to investigate the effects of meperidine on nonshivering thermogenesis in a model of thermoregulation in mice. After injection (0.1 mL/kg intraperitoneally) of saline, meperidine (20 mg/kg), the specific alpha2-adrenoceptor antagonist atipamezole (2 mg/kg), plus saline or atipamezole plus meperidine, respectively, mice were positioned in a Plexiglas chamber. Rectal temperature and mixed expired carbon dioxide were measured after provoking thermoregulatory effects by whole body cooling. Maximum response intensity of nonshivering thermogenesis and the thermoregulatory threshold for nonshivering thermogenesis, which was defined as the temperature at which a sustained increase in expiratory carbon dioxide can be measured, were investigated. Meperidine significantly decreased the threshold of nonshivering thermogenesis (36.6 degrees C +/- 0.7 degrees C) versus saline (37.9 degrees C +/- 0.6 degrees C) and versus atipamezole plus saline (37.8 degrees C +/- 0.4 degrees C; P <0.01). This effect was abolished after administration of meperidine combined with atipamezole (37.7 degrees C +/- 0.6 degrees C; P <0.05). Meperidine did not decrease the maximum intensity of nonshivering thermogenesis. The results suggest a major role of alpha2-adrenoceptors in the inhibition of thermoregulation by meperidine in mice.

Adrenergic alpha-Antagonists↗

PubMed2005

Sevoflurane but not propofol preserves myocardial function during minimally invasive direct coronary artery bypass surgery.

Volatile anesthetics exert cardioprotective properties in experimental and clinical studies. We designed this study to investigate the effects of sevoflurane on left ventricular (LV) performance during minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass. Fifty-two patients scheduled for MIDCAB surgery were randomly assigned to a propofol or a sevoflurane group. Apart from the anesthetics used, there was no difference in surgical and anesthetic management. After determination of cardiac troponin T, creatine kinase, and creatine kinase MB, electrocardiographic (ECG) data and echocardiography variables (myocardial performance index and early to atrial filling velocity ratio) the left anterior descending coronary artery (LAD) was clamped until anastomosis with the left internal mammary artery was completed. During LAD occlusion and during reperfusion, echocardiography measurements were repeated. Blood samples were obtained repeatedly for up to 72 h. After LAD occlusion, myocardial performance index and early to atrial filling velocity ratio in the propofol group deteriorated significantly from 0.40 +/- 0.12 and 1.29 +/- 0.35 to 0.49 +/- 0.10 and 1.13 +/- 0.22, respectively, whereas there was no change in the sevoflurane group. In the propofol group myocardial performance index remained increased (0.47 +/- 0.11) compared with baseline during reperfusion. There were no significant differences in ECG and laboratory values between groups. In conclusion, during a brief period of ischemia in patients undergoing MIDCAB surgery, sevoflurane preserved myocardial function better than propofol.

Adult↗

PubMed2005

Neuroendocrine stress response and heart rate variability: a comparison of total intravenous versus balanced anesthesia.

Attenuating intraoperative stress is a key factor in improving outcome. We compared neuroendocrine changes and heart rate variability (HRV) during balanced anesthesia (BAL) versus total IV anesthesia (TIVA). Forty-three patients randomly received either BAL (sevoflurane/remifentanil) or TIVA (propofol/remifentanil). Depth of anesthesia was monitored by bispectral index. Stress hormones were measured at 7 time points (P1 = baseline; P2 = tracheal intubation; P3 = skin incision; P4 = maximum operative trauma; P5 = end of surgery; P6 = tracheal extubation; P7 = 15 min after tracheal extubation). HRV was analyzed by power spectrum analysis: very low frequency (VLF), low frequency (LF), high frequency (HF), LF/HF ratio, and total power (TP). LF/HF was higher in TIVA at P6 and TP was higher in TIVA at P3-7 (P3: 412.6 versus 94.2; P4: 266.7 versus 114.6; P5: 290.3 versus 111.9; P6: 1523.7 versus 658.1; P7: 1225.6 versus 342.6 ms2)). BAL showed higher levels of epinephrine (P7: 100.5 versus 54 pg/mL), norepinephrine (P3: 221 versus 119.5; P4: 194 versus 130.5 pg/mL), adrenocorticotropic hormone (P2 10.5 versus 7.7; P5: 5.3 versus 3.6; P6: 10.9 versus 5.3; P7: 20.5 versus 7.1 pg/mL) and cortisol (P7: 6.9 versus 3.9 microg/dL). This indicates a higher sympathetic outflow using BAL versus TIVA during ear-nose-throat surgery.

Adrenocorticotropic Hormone↗

PubMed2004

Comparison of esophageal Doppler, pulse contour analysis, and real-time pulmonary artery thermodilution for the continuous measurement of cardiac output.

OBJECTIVE: Continuous measurement of cardiac output (CCO) is of great importance in the critically ill. However, pulmonary artery thermodilution has been questioned for possible complications associated with right heart catheterization. Furthermore, measurements are delayed in the continuous mode during rapid hemodynamic changes. A new pulmonary artery catheter CCO device (Aortech, Bellshill, Scotland) enabling real-time update of cardiac output was compared with 2 different, less-invasive methods of CCO determination, esophageal Doppler and pulse contour analysis. DESIGN: Prospective, observational study. SETTING: University hospital, single institution. PARTICIPANTS: Patients scheduled for elective coronary artery bypass grafting (CABG). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: CCO measurements were analyzed using a Bland-Altman plot. Bias between CCO and pulse contour cardiac output (PCCO), and Doppler-derived cardiac output (UCCO) was (mean +/- 1 SD) -0.71 +/- 1 L/min versus -0.15 +/- 1.09 L/min, and between UCCO and PCCO -0.58 +/- 1.06 L/min. Bias was not significantly different among methods, nor were comparative values before and after cardiopulmonary bypass (p > 0.05). CONCLUSIONS: Agreement between the CCO method and both less-invasive measurements was clinically acceptable. There were no adverse events associated with the use of either device.

Aged↗