perceived exertion have been established. In contrast, patients presenting with acute prescriptions for corticosteroids should be regarded with the understanding that they pose higher risk of inflammatory onset, and will likely be in a period of relative recovery. As such, aerobic intervention for these patients should be limited to required activities of daily living as tolerated. Pa- tients taking corticosteroids for an acute asthmatic flare up may also benefit and/or require physical therapy treatment targeted toward breathing efficacy, and may include education/review of pursed-lip breathing techniques as well as active cycle breathing training.
tration for asthma is gradually tapered to prevent and/or limit tox- ic effects. Common inhaled corticosteroids used to treat asthma include fluticasone, beclomethasone, budesonide, ciclesonide, flunisolide and mometasone (Katzung, 2018, p. 355). With regards to physical therapy, distinction between sympatho- mimetic/adrenoreceptor agonist versus corticosteroid treatment of asthma is the key to formulating an appropriate plan of care for this patient population. Patients commonly present for physi - cal therapy across multiple settings (inpatient <> outpatient) with chronic prescription of albuterol to treat bronchospasm. As such, aerobic intervention for these patients is indicated, provided graded examination has been completed, and parameters of
CENTRAL NERVOUS SYSTEM PHARMACOLOGY
thetics, sedative-hypnotics, neuromuscular blocking agents and opioids. This approach seeks to utilize the most therapeutic prop- erties of each drug while simultaneously reducing adverse effects as much as possible. The primary points of contact for physical therapists with gen- eral anesthetics is the inpatient hospital setting, and generally includes patients presenting post-surgery and/or during critical/ intensive medical care. Patients who undergo orthopedic sur- gery, elective as well as traumatic, are regularly prescribed post- operative physical therapy. Current hospital practice standards have significantly reduced the period between surgical interven- tion and physical therapy evaluation. Therefore, physical thera - pists will treat patients who may present under relative influence of multi-modal general anesthesia. General functional concerns include decreased cardiac output due to decreased myocardial contractility, myocardial oxygen consumption and arterial pres- sure. In effect, patients presenting acutely post-operative require initial vital sign measurement to ensure hemodynamic stability and oxygen perfusion prior to progressive mobilization. The same can be said for patients receiving physical therapy in critical/inten- sive care units, though with additional respect to acute presenta- tion of decreased consciousness, especially for patients receiving ventilatory pulmonary support. Medical management for this pa- tient population often includes variable administration of general anesthetics, which can affect activity tolerance, participation and cognitive ability. Local anesthetics Similar respect should be paid to local anesthetics, which are commonly employed during orthopedic surgical intervention as an adjunct for post-operative pain control. The mechanism of ac- tion includes binding of drug molecules to voltage-gated sodium ion channels, which regulate neural signal conduction. These drugs are typically administered via injection to provide an acute analgesic block for sympathetic transmission afferent as well as ef- ferent signals related to pain, temperature, light touch and motor output (Katzung, 2018, p. 466). Common local anesthetics include lidocaine, ropivacaine and chloroprocaine. Local anesthetics are commonly applied at the caudal subarachnoid space, which in- duces analgesia distributed generally below the neural level of injection. Physical therapists will commonly encounter inpatients who have received local pharmaceutical anesthesia via epidural injection for purpose of orthopedic surgeries as well as labor and delivery. Average elimination half-life of lidocaine is 1.6 hours for patients presenting without severe hepatic disease; lidocaine is the current reference standard for local anesthetics (Katzung, 2018). Patients who have received localized anesthesia for their lower extremities present concern for musculoskeletal instability, with associated risks of falls and/or lower extremity injury. There- fore, it is important that physical therapists practicing in hospital settings where orthopedic intervention is followed by progressive mobilization use a physical examination to determine when it is appropriate to advance post-operative patients toward lower-ex- tremity weight-bearing positions. Lower extremity physical exam should include, but not be limited to, comparative measurement of knee extension and ankle dorsiflexion strength. Current efforts in the profession of clinical anesthesiology have gravitated toward
To review, the central nervous system (CNS) includes the brain and spinal cord. Thus, drugs that act on the CNS impose altera- tions on chemical synaptic transmission, either at the pre-synaptic or post-synaptic regions. CNS drugs include sedatives, general anesthetics, local anesthetics, drugs used in Parkinsonism and other movement disorders, antidepressants and opioids. Sedative-hypnotics Sedative-hypnotic pharmaceuticals include benzodiazepines, bar- biturates and specific hypnotics. Drugs within this pharmaceutical subgroup are used to promote sedation and/or sleep. In turn, this class of drugs is used for sedation during medical and surgical procedures, treatment of seizures/epilepsy, control of sedative- hypnotic and ethanol withdrawal states (detox), and muscle relax- ation in the presence of neuromuscular disorders (Katzung, 2018, p. 390). While their use is appropriated in acute hospital settings, this class of drugs is highly associated with chronic development of physiologic tolerance, as well as compulsive abuse due to per- ceived euphoria, anxiety relief, disinhibition and sleep promotion. Common sedative-hypnotics include alprazolam, buspirone, diaz- epam, lorazepam, phenobarbital and temazepam. General anesthetics General anesthetics reduce central nervous system activity to pro - duce states of variable sedation by inducing immobility, amne- sia and decreased consciousness. Despite clinical application for more than 170 years, the precise mechanism of action for gen- eral anesthetics is unknown. Inhaled anesthetics enter the blood stream via gas exchange within pulmonary alveoli, leading to sys- temic distribution, bypassing first-pass metabolism. The rate of pharmakinetic uptake can be quantified and controlled in terms of alveolar-venous partial pressure difference. Anesthesiologists may adjust anesthetic concentration as well as alveolar ventila- tion rate. Recovery from inhaled general anesthetic administration depends primarily on duration of administration, and is based on elimination of the drug from the brain. Following discontinuation of inhaled anesthetic administration, alveolar concentration di - minishes rapidly primarily via pulmonary ventilation, though with some respect to systemic metabolism depending upon the state of solubility. Common inhaled anesthetics include nitrous oxide, halothane, enflurane, isoflurane and sevoflurane (Katzung, 2018, p. 441). Intravenous anesthetic administration induces rapid onset of an - esthesia, and is the current preferred method of clinically induced anesthesia. Propofol is the most frequently administered pharma- ceutical for induction of anesthesia. Propofol is commonly applied for deep, as well as conscious, sedation in a variety of surgical and non-surgical settings, producing general reduction in CNS activity that includes decreased cerebral blood flow and peripheral va- sodilation (Katzung, 2018, p. 451). In addition to administration during surgical intervention, intravenous general anesthetics such as dexmedetomidine (aka precedex) are commonly applied for patients requiring intensive/critical care due to respiratory failure and/or systemic shock, as they can be precisely administered and titrated alongside patient medical presentation. Modern medicine has developed general anesthesia into a dy- namic process termed balanced anesthesia , which generally em- ploys multiple pharmaceuticals including inhaled general anes-
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