Monitoring im anästhesiologischen Alltag

Monitoring has made great strides in the last half century. It enables us to titrate drugs to the desired effect, warns us of impending danger, and helps with the diagnosis of problems confronting our patients. Beyond that it has enormously increased our understanding of anesthetic pathophysiology. Modern monitors, however, are still focused on single variables; they do not provide the panoramic view offered by our senses. They do not give data on the patient"s appearance, movement, or position. The clinician incorporates that type of information with the data provided by the monitors and melds that with a much richer information about the system in which he operates, the colleagues with whom he works and the circumstances that affect his patient. Even though we appreciate the importance of that wealth of information, we lack scientific tools to measure its value.     

Correlation of serum L-carnitine and dehydro-epiandrosterone sulphate levels with age and sex in healthy adults.

OBJECTIVES: L-carnitine and dehydro-epiandrosterone (DHEA) independently promote mitochondrial energy metabolism. We therefore wondered if an age-related deficiency of L-carnitine or DHEA may account for the declining energy metabolism associated with age. METHODS: we evaluated serum levels of L-carnitine and the sulphated derivative of DHEA (DHEAS) in cross-sectional study of 216 healthy adults, aged 20-95. RESULTS: serum DHEAS levels declined, while total carnitine levels increased with age (P < 0.0001). Total and free carnitine and DHEAS levels were lower in women than men (P < 0.0001). Esterified/free (E/F) carnitine (inversely related to carnitine availability) increased with age in both sexes (P=0.012). CONCLUSION: reduced carnitine availability correlates with the age-related decline of DHEAS levels. These results are consistent with the hypothesis that decreased energy metabolism with age relates to DHEAS levels and carnitine availability.     

Continuous transthoracic echocardiography in a 93-year-old patient with hypertrophic cardiomyopathy during electroconvulsive therapy

Electroconvulsive therapy (ECT) is the treatment of choice for patients with a major depression disorder who have failed antidepressant therapy. Patients with hypertrophic cardiomyopathy (HCM) may have dynamic obstruction to left ventricular (LV) outflow. The effects on myocardial function during ECT and pretreatment with antihypertensive agents in patients with HCM and LV outflow tract obstruction gradients are unknown. We report the first use of continuous transthoracic echocardiography during ECT in a patient with HCM. We confirmed an outflow tract obstruction and showed a decrease in LV outflow tract gradients. Continuous transthoracic echocardiography monitoring using Doppler echocardiography during ECT is feasible.     

Effects of hypocapnia on canine spinal,subcortical, and cortical somatosensory-evoked potentials during isoflurane anesthesia

Although hyperventilation with hypocapnia is frequently used in the management of neurosurgical patients in whom sensory-evoked potentials may be monitored, the effects of hypocapnia on evoked potentials have not been described with precision. In the present experiment, the effects of randomized arterial carbon dioxide tensions of 20, 25, 30, and 35 mm Hg on spinal, subcortical, and cortical somatosensory-evoked potentials (SEPs) were measured in dogs anesthetized with 1.40% isoflurane. Other variables known to affect the SEP (temperature, blood pressure, and arterial oxygen tension) were stable throughout the experiment. Hypocapnia caused reductions in the latencies of the early peaks of the spinal and subcortical SEPs. These differences were small, consisting of a 2% shortening of latency at 20 mm Hg carbon dioxide tension when compared with 35 mm Hg. No changes were detected in the later subcortical and cortical latencies. SEP amplitudes were also unchanged. These results in a controlled animal study corroborate the direction and magnitude of changes due to hypocapnia observed by other investigators in surgical patients. The magnitude of the changes indicates that SEP monitoring sensitivity is not compromised by clinically useful levels of induced hypocapnia during isoflurane anesthesia. Because hypocapnia may produce small SEP changes, baseline recordings should be acquired prior to initiation of hyperventilation. It is not warranted, however, to impute a severe deterioration of the SEP to hypocapnia alone, and causes must be sought elsewhere in a patient's status and management.Supported by the Department of Anesthesiology Research and Development Fund, University of Wisconsin. Isoflurane was provided by Anaquest, Inc., Liberty Corner, NJ.