Biomedical subjects

E Kochs

Publications and source records attributed to E Kochs.

154 records · Page 9Linked to original sources

PubMed1988

[Intraoperative determination of heart time volume with transesophageal pulsed Doppler echocardiography].

Stroke volume and cardiac output (CO) can be determined noninvasively by means of the pulsed Doppler technique to measure blood flow velocities in specified regions of the heart or neighboring great vessels along with 2D-echocardiographic imaging to measure the diameter of vessels or valve orifices. Disadvantages of the transthoracic approach, such as precordial inaccessibility and instability of the probe position, have prevented the continuous application of pulsed Doppler echocardiography during surgery. Recently, we presented a new technique using the transesophageal approach with combined pulsed Doppler measurements and 2D-echocardiographic imaging. This study was designed to assess the feasibility of transesophageal pulsed Doppler echocardiography (TDE) for CO measurements during surgery and to test the method for accuracy against the thermodilution technique (TD) as well as evaluate its ability to track dynamic CO changes during general anesthesia. Transmitral and pulmonary artery flow analysis using TDE was performed in 35 adult patients undergoing a variety of surgical procedures under general anesthesia. For the transesophageal approach we used the prototype of a new 5-MHz phased array transducer with 64 elements fixed at the distal end of a 9 mm gastroscope. The mitral valve flow methods combined the velocity of transmitral flow at the mitral anulus with the cross-sectional area of the anulus calculated from its diameter at middiastole, while the pulmonary flow method combined the velocity of pulmonary artery flow with the cross-sectional area of the vessel calculated from its diameter during early systole. High-resolution 2D-echocardiograms of the mitral valve allowed accurate diameter measurements of the mitral valve orifice in all patients. A fixed esophageal transducer position behind the left atrium enabled continuous transmitral Doppler recordings of invariably high quality to be made. Regression analysis of TDE-CO vs. TD-CO for 50 measurements in 27 patients yielded a good correlation (r = 0.95, y = 0.95x + 0.42, SEE = 0.34 l/min). Use of halothane in 8 further patients resulted in a 21.0 +/- 5.9% and 37.3 +/- 11.7% decrease of TDE-CO at 1.0 MAC and 1.5 MAC, respectively. Transesophageal images adequate to determine the cross-sectional area of the pulmonary artery could be obtained in 16 of 27 (59.3%) patients. CO determined by the TDE pulmonary flow method (28 measurements in 16 patients) correlated with the TD-CO, with an r value of 0.91 and SEE 0.49 l/min.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1987

Electrophysiological effects of intravenous dantrolene on canine heart.

The electrophysiological effects of an intravenous dantrolene infusion (10 mg kg-1) were evaluated in healthy, anaesthetized dogs by intracardiac electrophysiological study. Dantrolene administration resulted in a significant prolongation of the refractory periods of the right atrium and ventricle, while the functional refractory period of the AV node was not altered. A slight increase of AV nodal conduction, measured as atrial-His bundle interval, without any change in infranodal conduction, measured as His bundle-ventricular interval, was observed during sinus rhythm. Dantrolene had no significant effects on surface ECG parameters. We conclude that intravenously administered dantrolene, at the maximal recommended doses, has primary effects on electrophysiological parameters. These findings support the hypothesis that the beneficial effects of dantrolene on cardiac arrhythmias associated with malignant hyperthermia may be related to its intrinsic activity on the electrophysiological properties of the heart, but confirmation requires further investigations on induced arrhythmias in experimental models.

Animals↗

PubMed1986

[Course of central body temperature in the laminar airflow operating room in various anesthesia procedures].

The oesophageal body temperature of 130 patients was measured pre- and intraoperatively. 92% (n = 116) of the operations (implantation or replacement of hip prostheses) were performed in an operating room having a laminar air flow system with horizontal air flow. 9% (n = 14) of the operations (laparotomies) were performed in a room of identical design without an air circulation system. Three different forms of anesthesia were investigated with regard to their influence on interior body temperature: 1) general anesthesia with a volatile anesthetic (INH); 2) peridural anesthesia with additional general anesthesia (KPDA+ITN); and 3) neuroleptic anesthesia (NLA). A drop in temperature during the operation was found in all patients. In the conventional operating room the mean drop was 0.3 degrees C/h. In the operating room with laminar air flow the INH-patients sustained the greatest decrease in temperature; the mean value in the first hour was 1.1 degrees C/h, and up to 4.6 degrees C/3 h toward the end of the operation. There was a comparable drop in temperature in the first hour in patients anesthetized with KPDA+ITN, but the rate slowed down toward the end of the investigation (2.2 degrees C/3 h). NLA caused a characteristic temperature behavior, with an initial fall in temperature, plateau phase, and subsequent rise (total: -1.0 degrees C/3 h) Temperature regulation was influenced least by NLA in the operating room with laminar air flow; thus, in this context, NLA proved to be a favourable form of anesthesia.

Anesthesia, Epidural↗

PubMed1986

[Increase in somatosensory evoked potentials during anesthesia induction with etomidate].

In 43 patients the time-dependent behaviour of somatosensory evoked potentials (SSEP) before and during induction of anesthesia with 0.3 mg/kg etomidate was studied. The SSEP components could be reliably recorded in one-minute intervals and the modulations of SSEP (early and middle latencies) following bolus injection with its pharmacokinetically non-stationary states could be quantified. The central conduction time (CCT) between the cervical N13- and the cortical N20-component was less prolonged (from 5.6 ms to 6.4 ms) than known from other anesthetics. Middle latency SSEP exhibited a more marked increase and were reduced in amplitude. All patients showed a 2- to 12-fold increase of the primary complex N20/P25 2-3 min after bolus injection. This amplification cannot be explained either by muscle artifacts nor exclusively by activation of muscle afferents. Myoclonia as a side effect of etomidate coincide with the increase of SSEP-components. The combination of myoclonia and SSEP-enhancement is known to be associated with the familial progressive myoclonus epilepsy. This observation therefore may indicate a cortical excitatory or disinhibitory effect, although no spike-wave complexes have been reported in the EEG after etomidate.

Adult↗

PubMed1985

[Clinical experiences with the anesthesia and brain monitor (ABM)].

The Anaesthesia and Brain Monitor (ABM) was employed in 83 patients (of 24 to 86 years of age) who were subjected to abdominal surgery, and in 21 intensive-care patients under artificial respiration and sedative treatment (of 45 to 74 years of age), the equipment being used for monitoring anaesthesia or sedation. With this method it became possible to effect a largely integrated surveillance of EEG, EMG, NMT, pCO2, as well as, if desired, external blood pressure measurement by time-synchronous measurement and integration of parameters largely used singly in clinical practice to date. Whereas the EEG parameters (amplitude, frequency), if considered singly, do not yield clear information on the stage of anaesthesia, they can supply additional information especially in very light or very deep anaesthesia, together with the other measured parameters. In intensive care, they afford an estimation of the degree of the sedation.

Anesthesia, General↗

PubMed1985

[Use of high frequency jet ventilation in extracorporeal shockwave lithotripsy].

High frequency jet ventilation (HFJV) was used in 68 patients which were treated with extracorporal shock wave lithotripsy (ESWL) because of stone diseases in the upper urinary tract. The question was whether HFJV in combination with a semiclosed conventional circle system offered a practicable and safe technique to minimize the oscillations which are proportional to the applied tidal volume and to the diaphragmatic movements. With IPPV the mean distance of the stone movement was 32 mm, whereas with the application of HFJV the stones oscillated around their resting position within limits of 2 to 3 mm (ventilation frequency: 200-300/min, driving pressure: 0.6-1.1 bar, tidal volume: 3-8 1/min). The effectiveness of HFJV was monitored by the end-tidal carbon dioxide tension (PeCO2) during intermittently conventional ventilation with "adequate" tidal volumes (TV 15 ml/kg bw). The correlation between PeCO2 and simultaneous measured PaCO2 was r = 0,91. The application of HFJV enhances the efficiency of ESWL. So the treatment of stones of the upper urinary tract can be varied by more subtle dosage of the incoming shock wave energy and by stabilisation of the stones in the underlying ellipsoid of the energy focus.

Adolescent↗

PubMed1985

[Detection of venous embolism during intraoperative monitoring by two-dimensional transesophageal echocardiography].

12 patients (mean age: 81 +/- 9 years) undergoing total hip replacement because of transcervical femoral fractures were studied intraoperatively by two-dimensional transoesophageal echocardiography (TEE). The purpose of this study was to evaluate the ability of this new technique for detection of embolic events in the right heart by intraoperative 2D-TEE monitoring during hip surgery. In all patients (pts) we observed a transient increase of contrast intensity in the right atrium immediately after insertion of the acetabulum prosthesis ("snow flurry"). Contrast was maximal 15-20 seconds after insertion and persisted for approximately 2 min. While contrast intensity decreased in the minutes thereafter, in 3 pts contrast became more heterogeneous:we detected structures like "flakes" passing the right heart, sometimes circulating for some seconds in the right atrium respectively the right ventricle. Detected embolism was followed by a transient decrease of arterial pO2 (greater than 10 mmHg) in 5 pts. However, haemodynamic responses occurred infrequently; 4 pts experienced no changes at this moment. During insertion of the femoral prosthesis the contrast events were even more pronounced and persistent. In all pts we observed the appearance of "flake"-like structures passing the right atrium and the right ventricle, some measuring up to 6 cm in length. This was accompanied in 10 pts with a decrease (greater than 10 mmHg) of arterial pO2 and in 8 pts with a decrease (greater than 5 mmHg) of endtidal CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1984

[Hormones of the pituitary-adrenal cortex system in patients under long-term sedation with etomidate and fentanyl].

The influence of a long-term sedation with etomidate and fentanyl on the hormones of the pituitary gland and the adrenal cortex now five mechanically ventilated patients were studied. There is evidence that etomidate might diminish the plasma cortisol level in a dose dependent relationship. The urinary excretion of 17-OH-corticosteroids was found to stay within the normal range, whereas the corresponding excretion of the unbound cortisol stayed subnormal. In general no cortisol response was seen in connection with raised ACTH-plasma-levels. Surgical trauma and changes of dressing induced stress reactions with an exceeding rise in plasma cortisol levels. The plasma levels of prolactin showed a marked increase after the administration of fentanyl even in the presence of a high etomidate plasma level. 17-alpha-OH-progesterone and progesterone were found diminished at etomidate plasma levels greater than 1.0 micrograms/ml. In the "therapeutic range" there is found no linear dependency on the plasma etomidate level. From our preliminary results we cannot draw any conclusions about the mechanism how etomidate might inhibit cortisol synthesis and its influence on the metabolic rate, the hormonal feedback mechanisms and the cardiovascular system.

17-alpha-Hydroxyprogesterone↗

PubMedDate not supplied

Continuous spinal analgesia. Comparison between patient-controlled and bolus administration of plain bupivacaine for postoperative pain relief.

BACKGROUND AND OBJECTIVES: Adequate postoperative pain relief has been achieved in orthopedic patients by subarachnoid bolus administration of plain bupivacaine. This prospective randomized study compares bolus injections of bupivacaine with a patient controlled infusion via subarachnoid 28-gauge microcatheters for postoperative analgesia after elective hip replacement. METHODS: Forty-two patients (mean age, 69 +/- 11 years) were randomly allocated to one of two groups. Group. 1 patients received a constant subarachnoid infusion of 0.6 mg/h of bupivacaine by a patient-controlled device and were allowed to self-administer 0.6 mg every 30 minutes Group 2 patients received a nurse-administered bolus of 3.75 mg of plain bupivacaine on request. Pain was assessed by patients and nurses by a visual analog scale (VAS) every hour. The degree of motor block and the level of analgesia were documented every 4 hours. Hemodynamic and respiratory parameters were recorded hourly. Differences between groups were tested by analysis of variance for repeated measurement. RESULTS: Technical problems occurred in six patients were more frequent in group 1 but none in group 2. Patient-controlled analgesia resulted in lower pain scores than bolus application during 18 postoperative hours (VAS score 19 +/- 19 mm in group 1 and 39 +/- 30 mm in group 2; P < .01). Lower total doses of bupivacaine were required in group 1 (17.6 +/- 4 mg) than in group 2 (22.3 +/- 7 mg; P < .05). The groups did not differ with respect to the degree of motor block (Bromage score 3.5 +/- 0.5), the sensory level (L1-2 +/- 1), or hemodynamic or respiratory parameters. CONCLUSION: In spite of a higher incidence of technical problems, patient-controlled analgesia with a continuous background infusion via microspinal catheters provides more effective postoperative analgesia, without hemodynamic or respiratory side effects, than bolus administration.

Aged↗

PubMedDate not supplied

Concept for an intelligent anaesthesia EEG monitor.

Considering the fundamental difficulties to define the term 'depth of anaesthesia', a more feasible concept for assessment of 'adequacy of anaesthesia' will be explained. The basic requirements for a monitoring index are definite response, gradual scaling and independence from the anaesthetic technique used. Additionally the index should be predictive for appearance of clinical signs of an inadequate anaesthesia. Different signal-processing methods will be discussed to extract the relevant information from both the spontaneous and the evoked brain electrical activity. In this context well established methods like spectral analysis are investigated in combination with new and more sophisticated methods like bispectral analysis or wavelet decomposition. Since no single-parameter index has been defined for monitoring depth of anaesthesia, a set of EEG parameters may be more useful to take into account intra- and interindividual variability. In parallel to the description of the monitor concept, the investigation of neural nets and fuzzy techniques, in addition to or in substitution of conventional statistical methods, will be introduced. Examples are given for data quality assessment, parameter extraction and re-classification.

Algorithms↗