Anästhesie, Intensivtherapie, Notfallmedizin
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Anasth Intensivther Notfallmed · Feb 1989
[Noninvasive monitoring of gas exchange: methodologic prerequisites and clinical use].
The noninvasive determination of the respiratory gas exchange (measurement of oxygen uptake and carbon dioxide delivery) permits the calculation of cardiac output by Fick principle and of the actual energy requirement of the patient (indirect calorimetry). A system is presented for the continuous measurement of oxygen uptake and carbon dioxide delivery, that bases on simple components, which are available on most intensive care units. ⋯ The results reveal, that 4.4 hours after ECC the metabolic rate is close to the calculated basic metabolic rate. They demonstrate the importance of indirect calorimetry as a future bedside monitoring routine.
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Anasth Intensivther Notfallmed · Feb 1989
Review[Current possibilities and limits of transcranial Doppler sonography as a cerebral monitoring procedure].
Transcranial Doppler Sonography (TCD) can meet some requirements for an ideal measuring device of the cerebral circulation. TCD can measure non-invasively and repeatably blood flow velocities of basal cerebral arteries. Under the assumption of constant vessel diameters can altered flow velocities reflect alterations of cerebral blood flow. ⋯ Furthermore TCD has been applied in cerebrovascular diseases, during operations with extracorporal circulation and in patients with increased intracranial pressure. Unchanged diameters of basal cerebral arteries have been proven only for carbon dioxide variations and some drugs; this cannot be presupposed during alterations of mean arterial or intracranial pressure. If conditions as ventilation, hemodynamics and drug therapy are kept constant, TCD may be valuable for short-term-trend-detection of cerebral blood flow and intracranial pressure.
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Anasth Intensivther Notfallmed · Feb 1989
Comparative Study[Mechanomyography and electromyography--2 competing methods of relaxometry using vecuronium].
The recording of the evoked twitch tension has been the established reference method to quantitate neuromuscular blockade. The evoked compound electromyogram has been introduced later as a clinically more convenient alternative. We compared both methods in 20 patients in whom cumulative dose response curves of vecuronium and the time constants of weaning neuromuscular blockade were determined. ⋯ No significant differences between the two methods were found in the cumulative 90% blocking dose, the duration of block and the recovery time (25%-75%). These results are in agreement with communications of previous authors using different nondepolarizing muscle relaxants. In the absence of abnormal conditions such as neuromuscular disorders and hypothermia, recording of evoked electromyography is a clinically satisfactory method to quantitate neuromuscular blockade.
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Anasth Intensivther Notfallmed · Feb 1989
[The use of pulse oximetry in detecting disorders of the arterial oxygen status in the immediate postoperative phase exemplified by combination anesthesia with isoflurane].
Adequate respiratory monitoring should immediately indicate deteriorations of arterial oxygen status, e.g. hypoxia (paO2-decrease [mmHg]), hypoxaemia (caO2-decrease [ml/dl]) and hypoxygenation (saO2-decrease [%]). These alterations have been detected in the early postanaesthetic period only by the classical clinical criterias cyanosis and tachycardia. Therefore, O2-application often is recommended for the first 10 min postoperatively. ⋯ With respect to the limitations of the method (measurement of arterial O2-saturation in peripheral circulation using pulse wave as an inflow indicator of arterial blood into the capillary bed; increased Hb-derivative concentrations, e.g. COHb), pulse oximetry for estimation of partial O2-saturation (psO2) seems to be the respiratory monitoring of choice in the early postoperative period. In that sense it is superior to pO2 but inferior to saO2 and caO2.
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Anasth Intensivther Notfallmed · Feb 1989
[Intraoperative detection of air embolism and corpuscular embolism using pulse oximetry and capnometry. Comparative studies with transesophageal echocardiography].
19 patients undergoing total hip replacement in general anesthesia because of transcervical femur fractures were continuously monitored throughout surgery to detect any embolic events. Aside from the standard monitoring with ECG and control of arterial pressure in regular short intervals, the pulse-oximetry and capnography were applied for a comparative examination of their sensitivity in detecting gas and corpuscular embolisms. Transesophageal echocardiography (TEE) which allows an extensive assessment regarding the extent and differentiation between gaseous and corpuscular embolisms was chosen as a reference method. ⋯ In the 36 cases of echocardiographic detectable embolisms prospectively defined changes of the heart rate were observed in 17%, of the mean arterial pressure in 56%, of the end-expiratory CO2 partial pressure in 47% and of the arterial O2 saturation in 31% of the cases. The embolisms which had been categorized by means of TEE according to their severity reflected a decrease of the end-expiratory CO2 partial pressure in 25% of the cases with light, in 45% of the cases with moderate and in 69% of the cases with severe embolisms, whereas a decrease in arterial O2 saturation was detected in 8% with light, 27% with moderate and in 54% of the cases with severe embolisms. Corpuscular embolism had no stronger influence on the frequency of relevant changes of end-expiratory CO2 partial pressure and the arterial O2 saturation than did the gaseous emboli.(ABSTRACT TRUNCATED AT 250 WORDS)