By B. Gamal. Western Baptist College. 2018.
In clients should be closely monitored for signs of hepa- addition generic extra super cialis 100mg without a prescription, assess the environment for risk factors for injury discount extra super cialis 100mg without a prescription. It should be used the drugs, assisting clients to obtain laboratory tests, and teach- cautiously. CHAPTER 57 DRUGS THAT AFFECT BLOOD COAGULATION 847 NURSING Drugs That Affect Blood Coagulation ACTIONS NURSING ACTIONS RATIONALE/EXPLANATION 1. With standard heparin: (1) When handwriting a heparin dose, write out units This is a safety precaution to avoid erroneous dosage. Underdosage may cause thromboembolism, and overdosage may cause bleeding. In addition, heparin is available in several con- centrations (1000, 2500, 5000, 10,000, 15,000, 20,000, and 40,000 units/mL). To minimize trauma and risk of bleeding (b) Leave a small air bubble in the syringe to follow Locks drug into subcutaneous space and minimizes trauma dose (c) Grasp a skinfold and inject the heparin into it, at a To give the drug in a deep subcutaneous or fat layer, with minimal 90-degree angle, without aspirating. Whatever effective method is to fill the volume-control set method is used, it is desirable to standardize concentration of (eg, Volutrol) with 100 mL of 5% dextrose in water heparin solutions within an institution. Standardization is safer, and add 5000 units of heparin to yield a concentration because it reduces risks of errors in dosage. For example, administration of 1000 units/h requires a flow rate of 20 mL/h. Another method is to add 25,000 units of heparin to 500 mL of IV solution. With low–molecular-weight heparins: (1) Give by deep SC injection, into an abdominal skin fold, To decrease bruising with the patient lying down, using the same technique as standard heparin. After the initial dose of warfarin, check the international The INR is measured daily until a maintenance dose is established, normalized ratio (INR) before giving a subsequent dose. Give ticlopidine with food or after meals; give cilostazol 30 min before or 2 h after morning and evening meals; give clopidogrel with or without food. With prophylactic heparins and warfarin, observe for the absence of signs and symptoms of thrombotic disorders. With therapeutic heparins and warfarin, observe for de- crease or improvement in signs and symptoms (eg, less edema and pain with deep vein thrombosis, less chest pain and respi- ratory difﬁculty with pulmonary embolism). With prophylactic or therapeutic warfarin, observe for an Frequency of INR determinations varies, but the test should be INR between 2. With therapeutic heparin, observe for an activated partial thromboplastin time of 1. Platelet counts should be done every 2 days during the ﬁrst week of management and weekly until a maintenance dose is reached. With aspirin, clopidogrel, and other antiplatelet drugs, ob- serve for the absence of thrombotic disorders (eg, myocardial infarction, stroke) g. With cilostazol, observe for ability to walk farther without Improvement may occur within 2 to 4 wk or take as long as 12 wk. It may occur anywhere in the body, spontaneously or in response to minor trauma. With eptiﬁbatide and tiroﬁban, most major bleeding occurs at the arterial access site for cardiac catheterization. Gastrointestinal (GI) bleeding is fairly common; risks are increased with intubation. Blood in stools may be bright red, tarry (blood that has been digested by GI secretions), or occult (hidden to the naked eye but present with a guaiac test). Genitourinary bleeding also is fairly common; risks are increased with catheterization or instrumentation. Urine may be red (indi- cating fresh bleeding) or brownish or smoky gray (indicating old blood). Or bleeding may be microscopic (red blood cells are visi- ble only on microscopic examination during urinalysis). Surgical wounds, skin lesions, parenteral injection sites, the nose, and gums may be bleeding sites. Other adverse effects: (1) With heparin, tissue irritation at injection sites, tran- These effects are uncommon. They are more likely to occur with sient alopecia, reversible thrombocytopenia, paresthesias, large doses or prolonged administration. With thrombolytic drugs, observe for bleeding with all uses Bleeding is most likely to occur at sites of venipuncture or other and reperfusion dysrhythmias when used for acute myocardial invasive procedures. Drugs that increase risks of bleeding with anticoagulant, These drugs are often used concurrently or sequentially to de- antiplatelet, and thrombolytic agents: crease risks of myocardial infarction or stroke. Drugs that increase effects of heparins: (1) Antiplatelet drugs (eg, aspirin, clopidogrel, others) (2) Warfarin Additive anticoagulant effects and increased risks of bleeding (3) Parenteral penicillins and cephalosporins Some may affect blood coagulation and increase risks of bleeding c. Drugs that decrease effects of heparins: (1) Antihistamines, digoxin, tetracyclines These drugs antagonize the anticoagulant effects of heparin. Drugs that increase effects of warfarin: Mechanisms by which drugs may increase effects of warfarin in- (1) Analgesics (eg, acetaminophen, aspirin and other non- clude inhibiting warfarin metabolism, displacing warfarin from steroidal anti-inﬂammatory drugs) binding sites on serum albumin, causing antiplatelet effects, in- hibiting bacterial synthesis of vitamin K in the intestinal tract, (2) Androgens and anabolic steroids and others. Drugs that decrease effects of warfarin: (1) Antacids and griseofulvin May decrease GI absorption (2) Carbamazepine, disulﬁram, rifampin These drugs activate liver metabolizing enzymes, which acceler- ate the rate of metabolism of warfarin. Drug that may increase or decrease effects of warfarin: (1) Alcohol Alcohol may induce liver enzymes, which decrease effects by ac- celerating the rate of metabolism of the anticoagulant drug.
Increasing the the magnetic ﬁeld induces eddy currents in superﬁ- stimulus intensity recruits further peaks which fol- cial layers of the brain at right angles to the ﬁeld 100mg extra super cialis sale. This is illustrated in the neural tissue is stimulated electrically with both Fig purchase 100mg extra super cialis with amex. What differs is the later by a second peak due to the I2 wave (pyrami- method of delivery. Electrical currents induced by the magnetic ﬁeld These ﬂow parallel to the surface of the brain. The Disadvantages magneticﬁeldfallsoffrapidlywithdistancefromthe The major problem with transcranial electrical stim- coil: with a typical 12 cm-diameter round coil, ulation is that only a small fraction of the current the strength falls by half at a distance of 4–5 cm from ﬂows into the brain. Experi- between the electrodes on the scalp and produces ments in monkeys suggest that, even at the highest strong discomfort, local pain and contraction of the stimulus intensities, there is no signiﬁcant activa- scalp muscles. Magnetic stimulation Stimulation using different coils Like electrical stimulation, transcranial magnetic With standard round coils, the induced current in stimulationofthemotorcortex(TMS)readilyevokes the brain ﬂows from an annulus underneath the Stimulation of the motor cortex 43 coil, which is usually some 8–12 cm in diameter. The following excitation of cortical elements oriented direction of current ﬂow in the coil is optimal for paralleltothesurface,suchasstellatecellsorcortico- stimulation of the left hemisphere when counter- cortical connection ﬁbres (see Rothwell, 1997). Coilswound in a ﬁgure-of-8 shape provide a more focal stimulus, TMS can also activate pyramidal and the lowest threshold occurs when the induced axons directly current in the brain ﬂows from posterior to anter- ior at an angle approximately perpendicular to the ADwaveisproducedincorticospinalaxonstoupper line of the central sulcus (Mills, Boniface & Schubert, limb motoneurones when the coil is rotated or the 1992). Direct record- ingsofdescendingactivityobtainedinanaesthetised humansubjectsduringsurgeryhaveshownthatTMS Responses in upper limb muscles can produce D waves with a lower threshold than I Longer latency of EMG responses evoked by waves (Burke et al. An alternative possibil- produced by the two techniques is the time taken ity was raised by Nielsen, Petersen and Ballegaard for trans-synaptic activation of pyramidal neurones (1995). They found that the EMG responses evoked 44 General methodology by anodal stimulation 2–3 cm lateral to the vertex Conditioning stimulation occurred 1–2 ms earlier than those evoked from the Subliminal transcranial magnetic stimulation has vertex, and they interpreted this as direct stimula- been used extensively to investigate the corti- tion of corticospinal axons deep to cortex. In accor- cospinal control of all spinal cord circuits for dancewiththisinterpretation,epiduralrecordingsof which there are reliable methods of investigation corticospinal volleys in awake co-operative human (cf. It is impossible to focus the magnetic ﬁeld in order to restrict the extent of the induced current ﬂow only to speciﬁc cortical areas and, at rest, TMS induces responses in several muscles. A good way of focus- Critique: advantages, limitations, ing the stimulation on one muscle is to record the conclusions response from a voluntarily activated muscle, but it is then impossible to investigate changes in trans- Cortical stimulation may be used to evoke test mission produced by a voluntary contraction. It is responses and conditioning stimuli essential that the position of the coil on the scalp is stable throughout an experiment, and different Test responses methods have been proposed to ensure this. Man- During voluntary contraction, the recruitment ual ﬁxation against a reference grid marked on the sequence in a voluntarily activated motoneurone scalp is the simplest way (see Capaday, 1997). Alter- pool is similar for Ia and corticospinal inputs natively the position of the coil may be secured by a (cf. In any event, because fore be modiﬁed similarly by conditioning stimuli, thefocusingoftheresponseonaparticularmuscleis unless the conditioning volley alters (i) motor cortex dependentonthepositionofthecoiloverthescalp,it excitability (see below); (ii) presynaptic inhibition of is important that the subject does not move the neck Ia terminals mediating the afferent volley of the test during the session. A prac- Input–output relationship within the ticalconsequenceofthedifferenceinthesitesofacti- motoneurone pool vationinthehandareaisthatthresholdresponsesto electricalstimulation(duetodirectactivationofcor- As for the H reﬂex, the input–output relationship ticospinal axons) should be less affected by changes within the motoneurone pool is sigmoid, and it is incorticalexcitabilitythanthoseevokedbymagnetic important to set the stimulus intensity within the stimulation(duetotrans-synapticactivationofpyra- range corresponding to the steep (roughly linear) midal neurones). This has been used as a method part of the relationship (see Capaday, 1997). Eccles & Lundberg, 1957), small slow-twitch to large fast-twitch units (Bawa & and (ii) convergence from two different ﬁbre sys- Lemon, 1993). The intensity of the rest,Hreﬂexes and MEPs of similar size do not ne- stimuli is adjusted so that separate stimulation of cessarily recruit the same population of motoneu- either I or II does not elicit a post synaptic poten- rones (Nielsen et al. This could be because tial (PSP) in the motoneurone (ﬁrst two rows in the component of the corticospinal excitation trans- Fig. The consequence of this is then produces an EPSP in the motoneurone (last that a different modulation of the MEP and the H row inFig. In order to be inferring a speciﬁc effect on the volley mediating sure that stimuli are sufﬁcient to create EPSPs in either response. When EPSPs from different sources are evoked ducetemporalsummationinthemotoneuronepool, simultaneously in one motoneurone the resulting and it may be difﬁcult to deﬁne the exact arrival time EPSP can, at most, be equal to their algebraic sum of the ﬁrst corticospinal volley. Thus, excita- so in a muscle at rest where it is usual for motoneu- tory convergence onto common interneurones can rone discharge to depend on summation of sublim- be inferred when the EPSP on combined stimula- inal EPSPs. The method can also be Conclusions used to show convergence of two excitatory inputs onto common inhibitory interneurones, recording Theabilitytostudytheeffectsofcorticospinalvolleys the resultant IPSP in the motoneurone. Activation of system I evokes a test PSP (either EPSP or IPSP) in motoneurones, Spatial facilitation whereas activation of system II is without effect in themotoneuronebyitself. I (f ) 8 MN 0 16 (g) 8 (b) (c) 0 28 32 36 40 I I Latency (ms) 20 (h) II Q H reflex II I + II 10 I + II Interneurone Motoneurone 0 VL VM VL + VM Fig. Dashed and dotted vertical lines in (f ), (g): onset of the corticospinal peak and of the extra facilitation on combined stimulation, respectively. Adapted from Baldissera, Hultborn & Illert (1981)((a)–(c)), Marchand-Pauvert, Simonetta-Moreau & Pierrot-Deseilligny (1999)((d)–(g)) and Fournier et al. Spatial facilitation judged in the PSTH of Summation of two PSPs at a single units recordings premotoneuronal level Summation of EPSPs Here spatial facilitation involves comparing the This is illustrated in Fig. Inthis quadri- effects of two volleys delivered separately and cepsunit,thebackgroundﬁring(d)wasnotmodiﬁed together on the PSTHs of a single motor unit. However, when the two stimuli were to ﬁre only occasionally, but where a combination combined (g), there was a large facilitation of the of two EPSPs would often produce a discharge. As corticospinal peak (Marchand-Pauvert, Simonetta- aresult the effect on combined stimulation would Moreau & Pierrot-Deseilligny, 1999). The summation be greater than the sum of effects of separate stim- of two excitatory inputs in a motoneurone pro- uli.
Substitution of a brain stem pathway for a cortical one by retraining after a Brain Stem Pathways brain injury may reorganize subcortical con- trollers and increase motor recovery cheap 100 mg extra super cialis with visa. The pontine nuclei receive projections from the prefrontal and limbic areas noted in the dis- LOCOMOTOR FUNCTIONS cussion of the cerebellum cheap 100mg extra super cialis fast delivery, as well as from other association cortices such as the posterior pari- The brain stem, particularly the reticular for- etal, superior temporal, occipitotemporal, and mation, includes important structures for au- parahippocampal cortices. Each cortical area tomatic and volitional control of posture and projects to a specific lateral basis pontis region. Interacting with the cortex, deep As a general organizing principle, intercon- cerebellar nuclei, substantia nigra, and globus nected cortical areas like these share common pallidus, the brain stem has convergent areas subcortical projections. Reticu- Vestibulospinal and rubrospinal neurons are lospinal and propriospinal projections from the rhythmically modulated by cerebellar inputs, mesencephalic locomotor region (MLR) and primarily for extensor and flexor movements, pedunculopontine region synapse with lumbar respectively. In addition, chains of polysynap- spinal neurons and carry the descending mes- tically interacting propriospinal neurons have sage for the initiation of locomotion. Reticulospinal and propriospinal stimulation of the cerebellar fastigial nucleus fibers intermingle on the periphery of the ven- and the subthalamic nucleus that project to tral and lateral spinal tracts, where reticu- reticulospinal neurons, produce hindlimb lo- lospinal paths may come to be replaced by pro- comotor activity. These regions modulate spinal pattern generators for fibers connect motor neurons to axial, girdle, stepping in animal models and, presumably, in and thigh muscles. In a sense, A hemisection of the upper lumbar spinal the axial and proximal leg motor pools are cord is followed by considerable recovery of lo- wired to interact together. The observer adjusts rats, the initiation of hindlimb locomotion is direction so as to cancel the error between the not compromised after a thoracic spinal cord heading perceived from optic flow and the injury (SCI) until almost all of the ventral white goal. Fibers from complished in the absence of vision, using the pontomedullary medial reticular formation vestibular or auditory signals. The re- ordinating the sensory cues for orientation be- gions that participate in the initiation of step- haviors during ambulation and other activities. Cholinergic antagonists and The output message from what are mostly mul- GABA abolish MLR-evoked locomotion. This comotion by modulating amygdala and hip- synthesis allows a remarkably simple neural pocampal inputs to the nucleus accumbens, mechanism for a very flexible range of motor which projects to the MLR via the ventral pal- responses in the face of a changing environ- lidal area. In clinical practice, visual input may contains glutaminergic fibers and noradrener- compensate for proprioceptive impairments gic fibers that descend from the locus during gait retraining, but may impede step- coeruleus. The use of systemic drugs that in- ping and postural adjustments when associated crease or block the neurotransmitters of this with perceptual deficits. These brain stem locomotor regions are af- Spinal Sensorimotor Activity fected by a variety of neurologic diseases. Their gait deviations in- the brain into simple (reflexes), rhythmic clude difficulty in the initiation and rhythmic- (walking, breathing, swallowing), and complex ity of walking. In a case report, a patient who (speaking, reaching for a cup) movements. Most im- Locomotor activity also requires constant portantly, the spinal motor pools are an inte- processing of information from the environ- gral part of motor learning. Brain stem circuits help mediate this in- cord reveals a considerable degree of experi- formation. Visual control of walking includes ence-dependent plasticity that is induced, ad- an egocentric mechanism. A person perceives justed, and maintained by descending and seg- the visual direction of the destination with re- mental sensory influences. As described later un- The motoneurons of the spinal cord are der Spinal Primitives, the caudal thoracic and arranged in 11 rostocaudal columns, shown in the lumbar motor pools are also linked to the Figure 1–4. These columns originate and ter- circuitry for locomotor rhythm generators and minate at several levels of the cord. The columnar more laterally from C-8 to S-3 (column 2), L- organization becomes a source for plasticity when descending activity is diminished by a CNS injury. Any descending or segmental af- ferent activity becomes a weightier input that may help drive activity in all the cells of the column and between columns, but this plas- ticity requires practice of motor skills. These columns are potentially important targets for biologic interventions that reinstate some supraspinal input after a spinal cord injury (see Chapter 2). VENTRAL HORNS Within a ventral horn, motoneurons can be mapped in three dimensions. The muscles of the most distal joints have their motoneurons situated most dorsally in the ven- tral horn. Mediolaterally, the hip adductor and abductor pools are most medial, the flexors of the hip and knee are more lateral, and the ex- tensors of the hip and knee are most lateral. The motoneurons for the axial muscles are al- ways medial to those for more distal muscles. The anatomical organization of the spinal pools and their passive and active membrane properties, fatigue characteristics, and re- sponses to various neurotransmitters permit considerable adaptability. The muscles inner- vated at the other end of the motor unit are also quite adaptable, as discussed in Chapter 2. Modulatory inputs from amines and peptides alter motor pool excitability over a variety of Figure 1–4. Drawing of the 11 columns of motoneurons time scales to assist the timing and magnitude of the spinal cord. Source: Routal and Pal, 1999145 with ders of recruitment of motoneurons, including permission. The in- SPINAL REFLEXES vestigators operantly conditioned the H-reflex Many theories of physical therapy focus on the in monkeys to increase or decrease in ampli- use of brain stem and spinal reflexes as a way tude.
The American Lung Association publishes along with the INH to prevent leg numbness and tingling generic extra super cialis 100mg free shipping. Additional on an empty stomach if possible; if stomach upset oc- information is available on the Internet purchase extra super cialis 100mg online. Any one of these regimens This prevents expelling tuberculosis germs into the can be effective in preventing active disease if the drugs surrounding air, where they can be inhaled by and in- are take correctly and for the time prescribed. Place the used tissues in a waterproof and watch for signs and symptoms of hepatitis (eg, nau- bag, and dispose of the bag, preferably by burning. If such symptoms occur, you should stop taking ✔ A nourishing diet and adequate rest help healing of in- the drugs and report the symptoms to the nurse or physi- fection. If not taken in the doses and for after symptoms of liver damage occurred. This is harmless, addition, this very serious infection can be spread to except that soft contact lenses may be permanently family members and other close contacts. This is extremely important because the information tive tablets; a different type of contraception should be can help you understand the reasons long-term treatment used during rifampin therapy. These formulations are more expensive than and whether multidrug-resistant strains are being iso- separate drugs. Multiple drugs are required to inhibit emergence of drug-resistant organisms. Duration of drug therapy varies with the purpose, extent of disease, and clinical response. How- years, for treatment of both latent and active disease, ever, in the United States, they have been most evident is to give short courses of treatment (eg, 6 months) in populations with AIDS, in closed environments when possible. Such regimens are more likely to be (eg, hospitals, prisons, long-term care facilities, home- completed and completion decreases the prevalence of less shelters), and in large urban areas. Fixed-dose combination tablets (eg, Rifamate and with MDR-TB or suspected of having MDR-TB should Rifater) are recommended by some authorities, because be designed in consultation with infectious disease they help to prevent the emergence of drug-resistant or- specialists. Treatment of MDR-TB requires concurrent adminis- of usual activities of daily living. Short-course regi- tration of more drugs (eg, 4 to 6), for a longer period mens, intermittent dosing (eg, 2 or 3 times weekly of time (eg, 2 years or longer), than for drug-susceptible rather than daily), and ﬁxed-dose combinations of tuberculosis. The speciﬁc regimen is derived from cul- drugs (eg, Rifater or Rifamate) reduce the number of tures of infecting strains and susceptibility tests with pri- pills and the duration of therapy. It should include 2 or 3 drugs to which the With clients for whom English is not their primary isolate is sensitive and that the client has not taken language, it is desirable to have a health care worker before. The ﬂuoroquinolones are not recommended for who speaks their language or who belongs to their eth- use in children. All drug therapy for suspected or known MDR-TB tively teach clients and others, elicit cooperation with should involve daily administration and DOT. HIV population, and costs many thousand dollars more than the treatment of drug-susceptible TB. Monitoring Antitubercular Drug Therapy Increasing Adherence to Antituberculosis There are two main methods of monitoring client responses Drug Therapy to treatment, clinical and laboratory. The current trend seems to be increasing clinical monitoring and decreasing laboratory Failure to complete treatment regimens is a major problem in monitoring. Identifying drug therapy and obtaining medical care (eg, hepato- and treating LTBI requires several steps, including adminis- toxicity). It also includes regular assessment by a tering and reading skin tests, obtaining medical evaluations health care provider. Clinical monitoring should be of infected persons, and initiating, monitoring, and complet- repeated at each monthly visit. Nonadherence is common in all of these as- sessed for signs of liver disease (eg, loss of appetite, pects. Numerous strategies have been proposed to increase nausea, vomiting, dark urine, jaundice, numbness or adherence, including: tingling of the hands and feet, fatigue, abdominal ten- 1. This may be es- derness, easy bruising or bleeding) at least monthly if pecially important with treatment of LTBI. Most peo- receiving INH alone or rifampin alone and at 2, 4, and ple are more motivated to take medications and schedule 8 weeks if receiving rifampin and pyrazinamide. In follow-up care when they have symptoms than when addition to detecting adverse effects, these ongoing they feel well and have no symptoms. The importance contacts are opportunities to reinforce teaching, as- of treatment for the future health of the individual, sess adherence with therapy since the last visit, and significant others, and the community must be em- observe for drug interactions. In addition, clients should be informed view form may be helpful in eliciting appropriate about common and potential adverse effects of drug information. Monitoring during therapy is indi- with inconvenient hours, long waiting times, and un- cated for patients who have abnormal baseline values supportive staff) may deter clients from being evalu- or other risk factors for liver disease and those who ated for a positive skin test, initiating treatment, or develop symptoms of liver damage. Some clinicians completing the prescribed treatment and follow-up recommend that INH be stopped for transaminase care. Individualizing treatment regimens, when possible, ciated with symptoms and five times the upper limit to increase client convenience and minimize disruption of normal if the patient is asymptomatic. CHAPTER 38 DRUGS FOR TUBERCULOSIS AND MYCOBACTERIUM AVIUM COMPLEX (MAC) DISEASE 571 Effects of Antitubercular are HIV-seronegative clients. The regimen may be longer if Drugs on Other Drugs the bacteriologic (eg, negative cultures) or clinical response (eg, improvement in symptoms) is slow or inadequate. Isoniazid (INH) increases risks of toxicity with several drugs, A major difficulty with treatment of TB in clients with apparently by inhibiting their metabolism and increasing HIV infection is that rifampin interacts with many protease their blood levels. These include acetaminophen, carba- inhibitors (PIs) and nonnucleoside reverse transcriptase in- mazepine, haloperidol, ketoconazole, phenytoin (effects of hibitors (NNRTIs). If the drugs are given concurrently, ri- fampin decreases blood levels and therapeutic effects of the rifampin are opposite to those of INH and tend to predomi- anti-HIV drugs. Rifabutin has fewer interactions and may be nate if both drugs are given with phenytoin), and vincristine.
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