Free Lidocaine Concentrations During Continuous Epidural Anesthesia in Geriatric Patients:

[Anesthesiological care of trauma patients in orthogeriatric co-management]

Elderly patients increasingly need to undergo surgery under anesthesia, especially following trauma. A timely interdisciplinary approach to the perioperative management of these patients is decisive for the long-term outcome. Orthogeriatric co-management, which includes geriatricians and anesthesiologists from an early stage, is of great benefit for geriatric patients. Patient age, comorbidities and self-sufficiency in activities of daily life are decisive for an anesthesiological assessment of the state of health and preoperative risk stratification. If necessary additional investigations, such as echocardiography must be carried out, in order to guarantee optimal perioperative anesthesiological management. Certain medical factors can delay the initiation of anesthesia and it is absolutely necessary that these are taken into consideration for surgical management. Not every form of anesthesia is equally suitable for every geriatric patient.

[Anesthesiological care in orthogeriatric co-management. Perioperative treatment of geriatric trauma patients]

Elderly patients increasingly need to undergo surgery under anesthesia, especially following trauma. A timely interdisciplinary approach to the perioperative management of these patients is decisive for the long-term outcome. Orthogeriatric co-management, which includes geriatricians and anesthesiologists from an early stage, is of great benefit for geriatric patients. Patient age, comorbidities and self-sufficiency in activities of daily life are decisive for an anesthesiological assessment of the state of health and preoperative risk stratification. If necessary additional investigations, such as echocardiography must be carried out, in order to guarantee optimal perioperative anesthesiological management. Certain medical factors can delay the initiation of anesthesia and it is absolutely necessary that these are taken into consideration for surgical management. Not every form of anesthesia is equally suitable for every geriatric patient.

Epigenetics in the perioperative period

The perioperative period is characterized by profound changes in the body's homoeostatic processes. This review seeks to address whether epigenetic mechanisms may influence an individual's reaction to surgery and anaesthesia. Evidence from animal and human studies suggests that epigenetic mechanisms can explain many facets of susceptibility to acute and chronic pain, making them potential therapeutic targets. Modern pain management is still based upon opiates, and both the developmental expression of opioid receptors and opioid-induced hyperalgesia have been linked to epigenetic mechanisms. In general, opiates seem to increase global DNA methylation levels. This is in contrast to local anaesthetics, which have been ascribed a global demethylating effect. Even though no direct investigations have been carried out, the potential influence of epigenetics on the inflammatory response that follows surgery seems a promising area for research. There is a considerable body of evidence that supports the involvement of epigenetics in the complex process of wound healing. Epigenetics is an important emerging research topic in perioperative medicine, with a huge potential to positively influence patient outcome.

[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. As a result depth of anesthesia monitoring is recommended for geriatric patients to individually adjust the dosing to patients needs. 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.

Determination of lidocaine and its two N-desethylated metabolites in dog and horse plasma by high-performance liquid chromatography combined with electrospray ionization tandem mass spectrometry

A sensitive method for the quantification of lidocaine and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in animal plasma using high-performance liquid chromatography combined with electrospray ionization mass spectrometry is described. The sample preparation includes a liquid-liquid extraction with methyl tert-butylmethyl ether after addition of 2M sodium hydroxide. Ethylmethylglycinexylidide (EMGX) is used as an internal standard. For chromatographic separation, an ODS Hypersil column was used. Isocratic elution was achieved with 0.01 M ammonium acetate and acetonitrile as mobile phases. Good linearity was observed in the range of 2.5-1000 ng ml(-1) for lidocaine in both dog and horse plasma. For MEGX, linear calibration curves were obtained in the range of 5-1000 ng ml(-1) and 20-1000 ng ml(-1) for dog and horse plasma, respectively. In dog and horse plasma good linearity was observed in the range of 200-1500 ng ml(-1) for GX. The limit of quantification (LOQ) in dog plasma for lidocaine, MEGX and GX was set at 2.5 ng ml(-1), 20 ng ml(-1) and 200 ng ml(-1), respectively. For horse plasma a limit of quantification of 2.5 ng ml(-1), 5 ng ml(-1) and 200 ng ml(-1) was achieved for lidocaine, MEGX and GX, respectively. In dog plasma, the limit of detection (LOD) was found to be 0.8 ng ml(-1), 2.3 ng ml(-1) and 55 ng ml(-1) for lidocaine, MEGX and GX, respectively. In horse plasma the LOD's found for lidocaine, MEGX and GX, were 1.1 ng ml(-1), 0.5 ng ml(-1) and 13 ng ml(-1), respectively. The method was shown to be of use in pharmacokinetic studies after application of a transdermal patch in dogs and after an intravenous infusion in horses.

Effects of lidocaine with and without epinephrine on plasma epinephrine and lidocaine concentrations and hemodynamic values during third molar surgery

Lidocaine with epinephrine is currently the most common local anesthetic agent used for impacted third molar surgery. The purpose of the present study was to define the adverse hemodynamic effects and plasma concentrations of lidocaine and epinephrine on 17 healthy patients during the impacted teeth operations. Arterial blood pressure (systolic blood pressure, diastolic blood pressure), heart rate, peripheral oxygen saturation range, and electrocardiography were measured by an automatic noninvasive pressure device and monitor. High-performance liquid chromatography was used to measure the changes of plasma concentrations of epinephrine and lidocaine from blood samples taken 5 different times during the operation. We concluded that lidocaine-epinephrine is effective local anesthetic and had no important adverse events in healthy patients during the third molar surgery.

Regional Anaesthesia in the Elderly

The number of elderly patients presenting for anaesthesia and surgery has increased exponentially in recent years. Regional anaesthesia is frequently used in elderly patients undergoing surgery. Although the type of anaesthesia (general versus regional anaesthesia) has no substantial effect on perioperative morbidity and mortality in any age group; it intuitively makes sense that elderly patients would benefit from regional anaesthesia because they remain minimally sedated throughout the procedures and awaken with excellent postoperative pain control. However, a multitude of factors influence the outcome, such as the type, duration and invasiveness of the operation, co-existing medical and mental status of the patient and the skill and expertise of the anaesthesiologist and surgeon. These factors make it difficult to decide if and when one technique is equivocally better than another. Thus, it is more important to optimise the overall management of the patient during the perioperative period and, in most cases, it is the quality of the anaesthetic administered rather than the type of anaesthetic which is most important. Sedatives used for regional anaesthesia in the elderly should be short acting, easy to administer, have a low adverse effect profile and high safety margin. Midazolam, lorazepam, ketamine, propofol and low-dose opioids have been successfully used for sedation in the elderly. Aging affects the pharmacokinetics and pharmacodynamics of local anaesthetics, composition and characteristics of tissues and organs within the body, and physiological functions of the body. Changes in the systematic absorption, distribution and clearance of local anaesthetics lead to an increased sensitivity, decreased dose requirement and a change in the onset and duration of action in the elderly. Decreases in neural population, neural conduction velocity and inter-Schwann cell distance can lead to an increased sensitivity to local anaesthetics in the elderly. The addition of an opioid and epinephrine (adrenaline) has been shown to be useful in central neuraxial blockade. Epinephrine also can prolong the duration of peripheral nerve blocks. However, caution must be exercised as epinephrine has the potential for causing ischaemic neurotoxicity in peripheral nerves. Regional anaesthesia appears to be safe and beneficial in elderly patients; however, every anaesthetic administered must be assessed on a case-by-case basis and particular consideration should be given to the health status of the patient, the operation being performed and the expertise of the anaesthesiologist.