Der Anaesthesist
-
Review
[Anesthesia for geriatric patients : Part 2: anesthetics, patient age and anesthesia management].
Part 2 of this review on geriatric anesthesia primarily describes the multiple influences of age on the pharmacokinetics and pharmacodynamics of different anesthetic agents and their impact on clinical practice. In the elderly the demand for opioids is reduced by almost 50% and with total intravenous anesthesia the dosages of propofol and remifentanil as well as recovery times are more determined by patient age than by body weight. ⋯ With muscle relaxants both delayed onset of action and prolonged duration of drug effects must be considered with increasing age and as this may lead to respiratory complications, neuromuscular monitoring is highly recommended. The following measures appear to be beneficial for geriatric patients: thorough preoperative assessment, extended hemodynamic monitoring, use of short-acting anesthetics in individually adjusted doses best tailored by depth of anesthesia monitoring, intraoperative normotension, normothermia and normocapnia, complete neuromuscular recovery at the end of the procedure and well-planned postoperative pain management in order to reduce or avoid the use of opioids.
-
During the last 30 years intraoperative electrophysiological monitoring (IOEM) has gained increasing importance in monitoring the function of neuronal structures and the intraoperative detection of impending new neurological deficits. The use of IOEM could reduce the incidence of postoperative neurological deficits after various surgical procedures. Motor evoked potentials (MEP) seem to be superior to other methods for many indications regarding monitoring of the central nervous system. ⋯ When intraoperative MEP or electromyography guidance is planned, muscle relaxation must be either completely omitted or maintained in a titrated dose range in a steady state. The IOEM can be performed by surgeons, neurologists and neurophysiologists or increasingly more by anesthesiologists. However, to guarantee a safe application and interpretation, sufficient knowledge of the effects of the surgical procedure and pharmacological and physiological influences on the neurophysiological findings are indispensable.
-
Studies conducted shortly after the implementation of pulse oximetry (PO) into clinical practice 20-25 years ago revealed that many patients breathing room air during transfer from the operating room (OR) to the post-anesthesia care unit (PACU) directly after general anesthesia (GA) had a peripheral oxygen saturation (S(p)O(2)) below 90%. Moreover, it was shown that the detection of hypoxemia by clinical criteria is extremely unreliable. Meanwhile, the use of PO has become part of the obligatory standard monitoring during GA in Germany and many other countries. Likewise, the use of PO is standard care in the PACU although there are no official recommendations. However, for the time period in between, i.e. immediately after GA during transportation of patients from the OR to the PACU, monitoring of the S(p)O(2) in patients breathing room air is neither obligatory in Germany nor are there any official recommendations or guidelines in this respect. Given the introduction of shorter acting anesthetic agents within the last 25 years, the main goal of this study was to explore whether the incidence of hypoxemia in the immediate period after GA is still so high. Additional aims of this study were to examine whether the detection of hypoxemia based on clinical criteria can be confirmed to be very unreliable, what the risk factors for hypoxemia following GA are and how common it is in Germany to transport patients from the OR to the PACU without PO and supplemental oxygen. ⋯ The use of opioids and relaxants with short duration of action may have favorable effects on preventing hypoxemia and decreases of S(p)O(2). These measures will, however, not be sufficient to solve this problem because the highest risk factors for hypoxemia are patient-related. Despite knowing risk factors for oxygen desaturation, it is currently not possible to reliably predict which patients will become hypoxemic or have a decrease of S(p)O(2). Therefore, transportation of patients breathing room air from the OR to the PACU directly after GA without use of PO or supplemental oxygen seems to be questionable in terms of patient safety.