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Biomedical subjects

R Heinze

Publications and source records attributed to R Heinze.

8 recordsLinked to original sources
PubMed1989

[CO2-stunning of swine for slaughter from the anesthesiological viewpoint].

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.

Abattoirs↗
PubMed1988

A new multisensor pacing system using stroke volume, respiratory rate, mixed venous oxygen saturation, and temperature, right atrial pressure, right ventricular pressure, and dP/dt.

A new multisensor pacing device using respiratory rate (RR), stroke volume (SV), oxygen saturation (SO2), temperature (T), right atrial pressure (RAP), right ventricular pressure (RVP) and right ventricular dP/dt, has been developed. It consists of a 7F multisensor catheter and an external pacing unit. It allows simultaneous recording of the input signals and the corresponding data can be compared among the different parameters under identical conditions. Furthermore, several parameters can be combined in such a way as to form a new combination better suitable for rate responsive pacing. The response of each parameter to exercise was studied in 12 healthy volunteers (mean age: 28 years). Exercise testing was carried out using a bicycle ergometer, with workloads up to 200 W. The dynamic characteristics, response and sensitivity to changes of workloads of each parameter were analyzed and compared to one another. SO2 proved to be a quick responding parameter (less than 10 sec) with higher sensitivity in the low exercise range (less than 75 W), T, on the other hand, responded slowly (greater than 30 sec) to exercise changes and had the highest sensitivity in the exercise range beyond 75 W. RR displayed a slow response (greater than 30 sec) and an adequate sensitivity was only found in the upper exercise range (greater than 100 W). SV reacted rapidly to workload changes (less than 10 sec) but showed poor sensitivity at all exercise levels. RAP, RVP and dP/dt displayed quick responses and constantly good sensitivity throughout the workload range. Furthermore, respiratory rate was easily derived from the RAP curve. Special algorithms were developed for each parameter so that pacing rate would reproduce sinus rate behavior. We found that SO2 and all pressure parameter imitated sinus rate response quite well. When using parameter combinations, SO2 and T proved to be superior. Five patients (mean age 68 years) with third degree AV-block were stimulated temporarily using this system. Compared to fixed rate stimulation (VVI 70), exercise performance improved, using SO2 as the input parameter for rate response, by 25% to 50%.

Adult↗
PubMed1988

First clinical experience with an oxygen saturation controlled pacemaker in man.

This article describes the characteristics of a new implantable pacemaker controlled by right atrial oxygen saturation and reports the first clinical experience in man. During the observation period over 5 months, there was no evidence of malfunction due to tissue growth. The system's reaction to exercise changes proved to be quick (5 s to 17 s); decay times varied depending on the magnitude of the power previously performed. Under various exercise tests, the rate increase was linear to the stress load. Measurements of cardiac output showed the system's hemodynamic feedback and its potential self-optimization of pacing rate.

Aged↗
PubMed1987

[Stroke volume, central venous oxygen saturation and blood temperature as control parameters of frequency-adapted pacemaker stimulation].

In order to compare various physiological parameters under identical conditions and to evaluate the "optimal" combination of parameters for triggering a pacing system, a multisensor-catheter of 7 F size was developed. By this catheter placed in the right ventricular cavity, sinus rate (SR), mixed venous oxygen saturation (SO2), temperature (T) and stroke volume (SV) were continuously recorded in 7 volunteers. SR, T, SO2 and SV were analysed for their steady state relationships to workload (P) and for their dynamic characteristics during standardized exercise tests. During exercise the delay times of SR, SO2 and SV were less than 10 sec., whereas that of T was markedly longer ranging from 70 sec. at low exercise levels to 30 sec. at high levels (200 Watts). During recovery delay times of SR, SO2 and SV ranged from 5 to 10 sec., that of T ranged from 20 to 30 sec. The relationship of SR to the workload (0-200 W) performed was linear (r = 0.98), that of T was linear above 50 Watts (r = 0.92), that of SO2 followed an exponential function (r = 0.89). Initial changes of SV were independent (r = 0.02) of the extent of workload. The sensitivity (S = dV/dP) was calculated from the relationship of the parameters (V) measured to the level of exercise performed. SO2 was highly sensitive at the lower range of exercise (less than 75 W), T became constantly sensitive above 50 W, below 50 W the sensitivity of T was continuously decreasing. SR was constantly sensitive over the whole range of exercise (0-200 W), the initial change of SV was not sensitive to the extent of workload.

Adult↗
PubMed1986

Rate control with an external SO2 closed loop system.

In 20 volunteers (mean age 35.5 y) and 12 pacemaker patients (mean age 68.7 y), central venous oxygen saturation (SO2) was monitored continuously by means of an optical sensor integrated in an external transvenous pacing lead placed in the right ventricular cavity. From the SO2 signal recorded at rest and during various modalities of exercise, an algorithm for controlling pacing rate of an external pacing system was developed. An open loop system was used in the volunteers, allowing the comparison of the computed pacing rate with the individual intrinsic heart rate. There was an excellent correlation between the two frequencies as far as the dynamic characteristics and the steady state relationship were concerned. In five pacemaker patients who were stimulated via the external lead, a closed loop control of pacing rate was used. In one patient with a DDD pacemaker implanted for third degree AV-block, the rate response of the SO2 driven pacemaker was well in accordance with the rate attained with the implanted atrial triggered system. With both pacing modes, exercise capacity as determined on a symptom limited treadmill test was identical. In four patients (3 AV block III, 1 bradyarrhythmia) an improvement in exercise tolerance up to 65 percent could be demonstrated with the rate responsive pacing mode. In all patients, it could be shown that an autoregulating pacemaker system with SO2 is an open possibility.

Adult↗