Chapter 10. Interdisciplinary Pain Management Flashcards

Question

787. In the immediate postoperative period, why are parenteral pain medications best given by continuous infusion rather than intermittent intravenous (IV)/intramuscular (IM) boluses? (A) Opioid infusions do not cause nausea or vomiting (B) Continuous infusions are associated with higher serum concentrations of the drug (C) Opioid infusions are not associated with somnolence or respiratory depression, as opposed to intermittent opioid dosing (D) No need of monitoring pediatric patients with continuous opioid infusions as opposed to constant monitoring in patients with intermittent boluses (E) Boluses are associated with frequent periods of inadequate pain relief

Answer 1

787. (E) A., B., C., and D. The most common side effects found with narcotic administration are nausea or vomiting and pruritus. The former usually respond to perphenazine or prochlorperazine and the latter to diphenhydramine or promethazine. Because somnolence and respiratory depression can also occur, patients receiving infusions of narcotics require close attention, especially when the pain is so well-controlled that the pain stimulus of respiration is no longer present. E. Drugs can be given as boluses or continuous infusions. Boluses are easy to administer and provide rapid pain relief; however, they have the disadvantage of providing short periods of analgesia sometimes associated with side effects when serum drug concentration peaks, followed by inadequate pain relief while the level decreases until the next injection. Continuous infusions, conversely, avoid this roller coaster of pain relief followed by pain and provide continuous analgesia with low plasma levels of drugs even in newborns and infants.

Answer 2

788. (E) Postoperatively, when the oral route can again be used, methadone can be prescribed at a dose one- to twofold that of the IV route. Oral morphine sulfate can also provide adequate pain relief for moderate to severe pain. Codeine can be given orally alone or in combination with acetaminophen or aspirin for moderate pain; mild pain is relieved by acetaminophen alone in most cases. In any case, the most important aspect of postoperative pain control is to assess pain repeatedly with simple pain and behavior scales and to adapt pain medication to the pain scores provided by these scales and physiological findings.

Answer 3

789. (C) A. and B. These catheters can be left in place for as long as a week or more without concerns about infection, displacement, or discomfort. An alternate approach to the epidural space is catheter placement via the caudal route, but its proximity to the anus raises concern about puncture site infection in the postoperative period, especially in small children. C. and D. Spinal anesthesia has had limited indications in children and adolescents because of the incidence of postspinal headache in this age group. In newborns and infants, it provides anesthesia with a profound motor block for a short time (45- 100 minutes) and thus cannot be used for postoperative pain relief. It is indicated in infants born prematurely and are less than 45 to 60 weeks’ postconceptual age in whom general anesthesia and sedation have been shown to induce postoperative apnea.

Answer 4

790. (D) Opioid contracts are used in many adult practices, but their use is not common in pediatrics. The opioid contract clearly defines the expectations and responsibilities of the patient, parent, and medical caregiver. Guidelines from the Medical Society of Virginia’s special Pain Management Subcommittee have been employed by many pain physicians throughout the United States. Written documentation of both physician and patient responsibilities must include 1. Risks and complications associated with treatment using opioids 2. Use of a single prescriber for all painrelated medications 3. Use of a single pharmacy, if possible 4. Monitoring compliance of treatment a. Urine or serum medication levels screening (including checks for nonprescribed medications and substances) when requested b Number and frequency of all prescription refills c. Reasons for which opioid therapy may be discontinued

Answer 5

791. (E) There are several distinctions between pediatric pain concerns and adult pain concerns. Misconceptions about a child’s inability to feel pain persists. The belief that children “tolerate pain well” still prevails. Children continue to receive fewer analgesics than adults do in comparable settings. Adults indirectly require that children prove their pain to merit the administration of pain interventions. If a child does not act as if he or she is experiencing severe pain, the child is less likely to receive analgesic care. It appears that adults are more likely than children to be believed when they complain of pain or discomfort. Studies show that for similar surgeries in adult and pediatric patients, the adults receive more doses of analgesic medications. Neonates and young children do not display learned pain behavior and therefore do not express pain in an adult fashion. Adult caregivers often miss pain cues that are developmentally appropriate. Silence is interpreted as a sign of being comfortable. Similarly, immobility without facial grimace or focus on the pain source is interpreted as absence of pain. Yet, on direct questioning about the existence of pain, many children do affirm that they are experiencing pain. Children may lie quietly and enjoy television; however, they do not want to move because of fear of increased pain.

Answer 6

792. (C) The term “addiction” is familiar to medical and private sectors, but both factions often misuse the term as describing both physical and psychologic dependence. Addiction is a disease process involving the use of opioids wherein there is a loss of control, compulsive use, and continued use despite adverse social, physical, psychologic, occupational, or economic consequences. Physical dependence is a physiological state of adaptation to a specific opioid characterized by the emergence of a withdrawal syndrome during abstinence, which may be relieved totally or in part by readministration of the substance. Physical dependence is predictable sequelae of regular, legitimate opioid or benzodiazepine use and is not identical to addiction. The incidence of addiction in children receiving prescribed opioids is low. The present climate of drug-abuse prevention has, in part, emphasized the predatory nature of drug addiction and heightens fear in children and adults. More education is needed by lay people and health care professionals in distinguishing addiction from physical dependence. Patients who receive analgesics for a recognized pain complaint are not more likely to become addicted than the general population. The incidence of addiction in children receiving prescribed opioids is low.

Answer 7

793. (B) Neck injuries often are a result of motor vehicle accidents. Some studies have shown that up to 60% of patients injured in car accidents present to the hospital with neck pain. The term “whiplash” describes the resultant injury caused by an abrupt hyperextension of the neck from an indirect force.

Answer 8

794. (E) After a whiplash injury, symptoms may occur 12 to 24 hours later. This is because of the fact that muscular hemorrhage and edema may need to evolve prior to inciting a nociceptive response. The cervical flexors, specifically the sternocleidomastoid, scalene, and the longus colli undergo acute stretch reflex. Some fibers are torn.

Answer 9

795. (E) A substantial number of patients with whiplash have chronic symptoms. Prognostic indicators for chronic symptoms include numbness and pain in the upper extremity, use of a cervical collar for more than 12 weeks, requirement of home traction, physical therapy restarted more than once.

Answer 10

796. (E) Facial pain may occur after trauma. Examples include bullet wounds, maxillofacial surgery, and dental procedures. Some patients manifest constant burning pain, occasionally with tingling and intermittent stabbing. With trophic changes, edema, and redness, CRPS I should be suspected. In patients with burning pain, sympathetic blockade of the stellate ganglion may be effective. Amitriptyline may reduce pain.

Answer 11

797. (A) Rib fracture pain may cause a decrease in ventilatory function and increase in incidence of pulmonary morbidity. It has been found that epidural analgesia is an independent predictor of decreased mortality and incidence of pulmonary complications. Significant improvements in VC and FEV1 (forced expiratory volume) occur in patients with rib fractures who receive thoracic epidural bupivacaine compared with those that receive lumbar epidural morphine. There are no changes in hematocrit, oxygen saturation, platelet aggregation, or expiratory reserve volume.

Answer 12

798. (C) Trauma to the chest is a significant cause of morbidity and mortality. The pathophysiologic sequelae of multiple rib fractures, especially with flail chest, are pain and hypoxia. Hypoxia results from the ventilation and perfusion mismatch in the underlying contused lung. Uncontrolled pain can result in splinting and muscle spasms, which lead to decreased ventilation and atelectasis. The compromise in pulmonary function causes hypoxemia, an increase in shunt fraction, or infection.

Answer 13

799. (D) When comparing injuries in the thoracic and cervical spine areas after sustained trauma, it is observed that there are similar incidences of facet injuries in the upper thoracic spine and the cervical spine. By contrast, in the anterior elements, vertebral end-plate fracture and bone bruising are more common in the thoracic spine, whereas disc injuries predominate in the cervical spine. This raises the question whether interscapular pain is referred from the neck or arises locally. Investigations of pathology, to be correlated with the effect of local anesthetic blocks, should enable the clinician to distinguish the true pain source.

Answer 14

800. (C) Hemodynamic stability, minimal impairment of the patient’s level of consciousness and responsiveness, and adequate analgesia to reduce sympathetic hyperactivity and to allow patient rehabilitation efforts are the primary goals in the management of the patient with pain after traumatic injury. Uncontrolled pain following traumatic injury compounds the anxiety and posttraumatic sympathetic nervous system hyperactivity. Uncontrolled pain following traumatic injury has been associated with the development of posttraumatic stress disorder.

Answer 15

801. (A) Patients with spine injury are usually managed with systemic analgesic techniques because of the risk of SCI or obscuring ongoing neurologic assessment with epidural analgesic techniques. Systemic opioid analgesic techniques, such as intravenous PCA, allow patient titration of analgesia and ongoing neurologic evaluation. Adjuvant analgesics, such as acetaminophen, may improve pain relief while reducing opioid requirements and opioidrelated side effects. Intraoperative administration of epidural or intrathecal opioid analgesics with epidural catheter placement and maintenance of continuous postoperative epidural opioid analgesia is an excellent technique for postsurgical analgesia. The percutaneous exit site for the epidural catheter can be made some distance lateral to the surgical incision, minimizing the effects on wound healing or infection.

Answer 16

802. (B) Post–burn injury pain has two primary components: a relatively constant background pain and an intermittent procedure-related pain. Continuous IV infusion of opioid analgesics is an effective method of managing the background pain component. Morphine and fentanyl have been extensively used in this setting although rapid escalation of opioid dose requirement and hemodynamic instability are not uncommonly seen. Hydromorphone is another alternative. A continuous IV titration paradigm for methadone has been described which produces effective and stable analgesia with minimal hemodynamic effects. Patients receive an IV loading dose by IV infusion of methadone over an initial period of 2 hours at 0.1 mg/kg/h. The infusion is terminated prior to the end of the initial 2-hour period if the patient develops signs of excessive somnolence or respiratory depression. This initial loading dose infusion is followed by a maintenance infusion of 0.01 mg/kg/h of methadone. Transdermal preparations are not appropriate.

Answer 17

803. (C) Trauma patients with extremity injuries can be managed with a variety of techniques, including peripheral neural blockade, epidural analgesia, and systemic opioid analgesia. Adjuvant analgesics, such as acetaminophen and NSAIDs, are particularly effective in providing supplemental analgesia for orthopedic injuries, reducing opioid requirements and opioid-related side effects. Brachial plexus or peripheral neural blockade is effective for upper extremity injuries, whereas lumbar plexus or sciatic or femoral neural blockade techniques are effective for many lower extremity injuries. Continuous analgesia can be maintained with continuous plexus or peripheral nerve catheter techniques or continuous epidural analgesia. Monitoring for compartment syndrome may be necessary in some patients with extremity trauma, although low concentrations of local anesthetics (bupivacaine 0.125% or ropivacaine 0.2%) and opioids allow continued monitoring of compartment pressures and subjective changes in pain report in most patients. Intermittent interruption in continuous local anesthetic infusions may provide a greater margin of safety in patients at high risk for development of compartment syndrome.

Answer 18

804. (E) Effective analgesia is especially important in the postinjury rehabilitation of the patient with a chest injury such as rib fractures, flail chest, sternal fractures, or thoracostomy drainage tubes because of the risk of chest wall splinting and inadequate lung expansion and clearance of pulmonary secretions secondary to pain. Several studies have demonstrated a significant benefit in avoidance of endotracheal intubation, earlier postinjury extubation, decreased ventilator dependence, shorter stay in the ICU, shorter hospital stay, and improved postinjury rehabilitation with the use of continuous epidural analgesia with local anesthetic and opioid or intercostal neural blockade for pain management following chest injury.

Answer 19

805. (E) A. Most patients who sustain an injury to the spinal cord have also received massive trauma to the vertebral column and its supporting structures, and will have acute nociceptive pain arising from damage to structures such as bones, ligaments, muscles, intervertebral discs, and facet joints. Some acute musculoskeletal pain is also related to structural spinal damage and instability without necessarily having spinal cord damage. B. Pathology in visceral structures, such as urinary tract infections, bowel impaction, and renal calculi, will generally give rise to nociceptive pain, although the level of the injury will affect the quality of the pain. Therefore paraplegic patients may experience visceral pain that is identical to that in patients who have no spinal cord damage. However, tetraplegic patients may experience more vague generalized symptoms of unpleasantness that are difficult to interpret. C. The diagnosis of neuropathic pain is largely based on descriptors (sharp, shooting, electric, burning, and stabbing), and the pain is located in a region of sensory disturbance. Neuropathic at-level pain refers to pain with these features, and present in a segmental or dermatomal pattern within two segments above or below the level of injury. This type of pain is also referred to as segmental, transitional zone, border zone, end zone, and girdle zone pain, names that reflect its characteristic location in the dermatomes close to the level of injury. It is often associated with allodynia or hyperesthesia of the affected dermatomes. D. This type of pain, which is also referred to as central dysesthesia syndrome, central pain, phantom pain, or deafferentation pain, presents with spontaneous and/or evoked pain that is present often diffusely caudal to the level of SCI. It is characterized by sensations of burning, aching, stabbing, or electric shocks, often with hyperalgesia and it often develops sometime after the initial injury. It is constant but may fluctuate with mood, activity, infections, or other factors, and is not related to position or activity. Sudden noises or jarring movements may trigger this type of pain. Differences in the nature of below-level neuropathic pain may be apparent between those with complete and incomplete lesions. Both complete and partial injuries may be associated with the diffuse, burning pain that appears to be associated with spinothalamic tract damage. However, incomplete injuries are more likely to have an allodynia component because of sparing of tracts conveying touch sensations.

Answer 20

807. (E) A. IV administration of propofol, a GABAA receptor agonist, has been reported to be more effective than placebo in relieving neuropathic SCI pain. B. The efficacy of IV ketamine infusion in the management of neuropathic SCI pain has been evaluated. IV infusion of ketamine (bolus 60 μg followed by 6 μg/kg/min) results in a significant reduction in the evoked and spontaneous neuropathic pains associated with SCI. C. Clonidine administered spinally either alone or in combination with morphine may also be effective for the control of neuropathic SCI pain. Clonidine has been found to be more effective than morphine for pain relief in patients with SCI. Combinations of clonidine with other agents may also be effective.

Answer 21

808. (A) Drug exposure before organogenesis (before the fourth menstrual week) usually causes an all-or-none effect; either the embryo does not survive, or it develops without abnormalities. Drug effects later in pregnancy typically lead to single- or multiple-organ involvement, developmental syndromes, or intrauterine growth retardation

Answer 22

809. (E) A. The FDA has developed a five-category labeling system for all approved drugs in the United States. This labeling system rates the potential risk for teratogenic or embryotoxic effects, according to available scientific and clinical evidence. Category A: controlled human studies indicate no apparent risk to fetus. The possibility of harm to the fetus seems remote (eg, multivitamins). B. Category B: animal studies do not indicate a fetal risk or animal studies do indicate a teratogenic risk, but well-controlled human studies have failed to demonstrate a risk (eg, acetaminophen, butorphanol, nalbuphine, caffeine, fentanyl, hydrocodone, methadone, meperidine, morphine, oxycodone, oxymorphone, ibuprofen, naproxen, indomethacin, metoprolol, paroxetine, fluoxetine, and prednisolone). C. Category C: studies indicate teratogenic or embryocidal risk in animals, but no controlled studies have been done in women or there are no controlled studies in animals or humans. (eg, aspirin, ketorolac, codeine, propoxyphene, gabapentin, lidocaine, mexiletine, nifedipine, propranolol, sumatriptan). D. Category D: there is positive evidence of human fetal risk, but in certain circumstances, the benefits of the drug may outweigh the risks involved (eg, amitriptyline, imipramine, diazepam, phenobarbital, phenytoin, valproic acid). E. Category E is not part of the FDA labeling system. Category X is part of the FDA labeling system and includes drugs were there is positive evidence of significant fetal risk, and the risk clearly outweighs any possible benefit (eg, ergotamine).

Answer 23

810. (B) A. The FDA has developed a five-category labeling system for all approved drugs in the United States. This labeling system rates the potential risk for teratogenic or embryotoxic effects, according to available scientific and clinical evidence. Category A: Controlled human studies indicate no apparent risk to fetus. The possibility of harm to the fetus seems remote (eg, multivitamins). B. Category B Animal studies do not indicate a fetal risk or animal studies do indicate a teratogenic risk, but well-controlled human studies have failed to demonstrate a risk. (eg, acetaminophen, butorphanol, nalbuphine, caffeine, fentanyl, hydrocodone, methadone, meperidine, morphine, oxycodone, oxymorphone, ibuprofen, naproxen, indomethacin, metoprolol, paroxetine, fluoxetine, prednisolone). C. Category C: studies indicate teratogenic or embryocidal risk in animals, but no controlled studies have been done in women or there are no controlled studies in animals or humans. (eg, aspirin, ketorolac, codeine, propoxyphene, gabapentin, lidocaine, mexiletine, nifedipine, propranolol, sumatriptan). D. Category D: there is positive evidence of human fetal risk, but in certain circumstances, the benefits of the drug may outweigh the risks involved. (eg, amitriptyline, imipramine, diazepam, phenobarbital, phenytoin, valproic acid). E. Category X is part of the FDA labeling system and includes drugs were there is positive evidence of significant fetal risk, and the risk clearly outweighs any possible benefit. (eg, ergotamine).

Answer 24

811. (D) A. Aspirin remains the prototypical NSAID and is the most thoroughly studied of this class of medications. Prostaglandins appear to trigger labor, and the aspirin-induced inhibition of prostaglandin synthesis may result in prolonged gestation and protracted labor. B. and D. The use of ibuprofen during pregnancy may result in reversible oligohydramnios (reflecting diminished fetal urine output) and mild constriction of the fetal ductus arteriosus. Similarly, no data exist to support any association between naproxen administration and congenital defects. Because it shares the renal and vascular effects of ibuprofen, naproxen should be considered to have the potential to diminish ductus arteriosus diameter and to cause oligohydramnios. C. Circulating prostaglandins modulate the patency of the fetal ductus arteriosus. NSAIDs have been used therapeutically in neonates with persistent fetal circulation to induce closure of the ductus arteriosus via inhibition of prostaglandin synthesis. Patency of the ductus arteriosus in utero is essential for normal fetal circulation. Indomethacin has shown promise for the treatment of premature labor, but its use has been linked to antenatal narrowing and closure of the fetal ductus arteriosus.

Answer 25

812. (D) A. Although mixed agonist-antagonist opioid analgesic agents are widely used to provide analgesia during labor, they do not appear to offer any advantage when compared to pure opioid agonists. When compared, meperidine and nalbuphine provide comparable labor analgesia as well as similar neonatal Apgar and neurobehavioral scores. Use of either nalbuphine or pentazocine during pregnancy can lead to neonatal abstinence syndrome. B. Opioids are excreted into breast milk. Pharmacokinetic analysis has demonstrated that breast milk concentrations of codeine and morphine are equal to or somewhat greater than maternal plasma concentrations. Meperidine use in breast-feeding mothers via PCA resulted in significantly greater neurobehavioral depression of the breast-feeding newborn than equianalgesic doses of morphine C. Methadone levels in breast milk appear sufficient to prevent opioid withdrawal symptoms in the breast-fed infant. The American Academy of Pediatrics considers methadone doses of up to 20 mg/d to be compatible with breast-feeding. Recognition of infants at risk for neonatal abstinence syndrome and institution of appropriate supportive and medical therapy typically results in little short-term consequence to the infant. The long-term effects of in utero opioid exposure are unknown. D. Meperidine undergoes extensive hepatic metabolism to normeperidine, which has a long elimination t1/2 (18 hours). Repeated dosing can lead to accumulation, especially in patients with renal insufficiency. Normeperidine causes excitation of the CNS, manifested as tremors, myoclonus, and generalized seizures. Significant accumulation of normeperidine is unlikely in the parturient who receives single or infrequent doses; however, meperidine offers no advantages over other parenteral opioids.

Answer 26

813. (B) Few studies have focused on the potential teratogenicity of local anesthetic agents. Lidocaine and bupivacaine do not appear to pose significant developmental risk to the fetus. Only mepivacaine had a suggestion of teratogenicity in one study. However, the number of patient exposures was inadequate to draw conclusions. Animal studies have found that continuous exposure to lidocaine throughout pregnancy does not cause congenital anomalies but may decrease neonatal birth weight. Neither lidocaine nor bupivacaine appears in measurable quantities in the breast milk after epidural local anesthetic administration during labor. IV infusion of high doses (2-4 mg/min) of lidocaine for suppression of cardiac arrhythmias led to minimal levels in breast milk. Based on these observations, continuous epidural infusion of dilute local anesthetic solutions for postoperative analgesia should result in only small quantities of drug actually reaching the fetus. The American Academy of Pediatrics considers local anesthetics to be safe for use in the nursing mother.

Answer 27

814. (D) A. and B. Benzodiazepines are among the most frequently prescribed of all drugs and are often used as anxiolytic agents, as an aid to sleep in patients with insomnia, and as skeletal muscle relaxants in patients with chronic pain. First-trimester exposure to benzodiazepines may be associated with an increased risk of congenital malformations. Diazepam may be associated with cleft lip and cleft palate as well as congenital inguinal hernia. However, epidemiologic evidence has not confirmed the association of diazepam with cleft abnormalities; the incidence of cleft lip and palate remained stable after the introduction and widespread use of diazepam. Epidemiologic studies have confirmed the association of diazepam use during pregnancy with congenital inguinal hernia. C. and D. Aside from the risks of teratogenesis, neonates who are exposed to benzodiazepines in utero may experience withdrawal symptoms immediately after birth. In the breast-feeding mother, diazepam and its metabolite desmethyldiazepam can be detected in infant serum for up to 10 days after a single maternal dose. This is caused by the slower metabolism in neonates than in adults. Clinically, infants who are nursing from mothers receiving diazepam may show sedation and poor feeding. It appears most prudent to avoid any use of benzodiazepines during organogenesis, near the time of delivery, and during lactation.

Answer 28

815. (C) A. and C. Antidepressants are often employed in the management of migraine headaches as well as for analgesic and antidepressant purposes in chronic pain states. Amitriptyline, nortriptyline, and imipramine are all rated risk Category D by the FDA. The SSRIs, fluoxetine and paroxetine, are rated FDA risk Category B. Desipramine and all other conventional antidepressant medications are Category C. B. Amitriptyline, nortriptyline, and desipramine are all excreted into human milk. Pharmacokinetic modeling suggests that infants are exposed to about 1% of the maternal dose. Amitriptyline, nortriptyline, desipramine, clomipramine, and sertraline were not found in quantifiable amounts in nurslings and that no adverse effects were reported. D. Withdrawal syndromes have been reported in neonates born to mothers using nortriptyline, imipramine, and desipramine with symptoms that include irritability, colic, tachypnea, and urinary retention.

Answer 29

816. (A) A. The use of anticonvulsants during lactation does not seem to be harmful to infants. Phenytoin, carbamazepine, and valproic acid appear in small amounts in breast milk, but no adverse effects have been noted. B. and D. For patients contemplating childbearing who are receiving anticonvulsants, their pharmacologic therapy should be critically evaluated. Women who are taking anticonvulsants for neuropathic pain should strongly consider discontinuation during pregnancy, particularly during the first trimester. Consultation with a perinatologist is recommended if continued use of anticonvulsants during pregnancy is being considered. Frequent monitoring of serum anticonvulsant levels and folate supplementation should be initiated, and maternal α-fetoprotein screening may be considered to detect fetal neural tube defects. C. While anticonvulsants have teratogenic risk, epilepsy itself may be partially responsible for fetal malformations. Perhaps pregnant women taking anticonvulsants for chronic pain have a lower risk of fetal malformations than patients taking the same medications for seizure control.

Answer 30

817. (E) A. and B. Early studies of caffeine ingestion during pregnancy suggested an increased risk of intrauterine growth retardation, fetal demise, and premature labor. However, these early studies did not control for concomitant alcohol and tobacco use. Subsequent work that controlled for these confounding factors found no added risks with moderate caffeine ingestion, although ingestion of more than 300 mg/d was associated with decreased birth weight. Caffeine ingestion combined with tobacco use increases the risk for delivery of a low-birthweight infant. C. Ingestion of modest doses of caffeine (100 mg/d) in caffeine-naïve subjects produces modest cardiovascular changes in both mother and fetus, including increased maternal heart rate and mean arterial pressure, increased peak aortic flow velocities, and decreased fetal heart rate. The modest decrease in fetal heart rate and increased frequency of fetal heart rate accelerations may confound the interpretation of fetal heart tracings. Caffeine ingestion is also associated with an increased incidence of tachyarrhythmias in the newborn, including supraventricular tachyarrhythmias, atrial flutter, and premature atrial contractions. D. Many over-the-counter analgesic formulations contain caffeine (typically in amounts between 30 and 65 mg per dose), and one must consider the use of these preparations when determining total caffeine exposure. Moderate ingestion of caffeine during lactation does not appear to affect the infant. Breast milk usually contains less than 1% of the maternal dose of caffeine, with peak breast milk levels appearing 1 hour after maternal ingestion. Excessive caffeine use may cause increased wakefulness and irritability in the infant.

Answer 31

818. (B) A. and C. Two relatively rare conditions— osteonecrosis and transient osteoporosis of the hip—both occur with somewhat greater frequency during pregnancy. Whereas the exact etiology is not known, high levels of estrogen and progesterone in the maternal circulation and increased interosseous pressure may contribute to the development of osteonecrosis. Transient osteoporosis of the hip is a rare disorder characterized by pain and limitation of motion of the hip and osteopenia of the femoral head. Both conditions present during the third trimester with hip pain that may be either sudden or gradual in onset. Osteoporosis is easily identified by plain radiography, which demonstrates osteopenia of the femoral head with preservation of the joint space. Osteonecrosis is best evaluated with magnetic resonance imaging (MRI), which shows changes before they appear on plain radiographs. B. and D. The hormonal changes that occur during pregnancy lead to widening and increased mobility of the sacroiliac synchondroses and the symphysis pubis as early as the 10th to 12th weeks of pregnancy. This type of pain is often described by pregnant women and is located in the posterior part of the pelvis distal and lateral to the lumbosacral junction. Many terms have been used in the literature to describe this type of pain, including “sacroiliac dysfunction,” “pelvic girdle relaxation,” and even “sacroiliac joint pain.” The pain radiates to the posterior part of the thigh and may extend below the knee, often resulting in misinterpretation as sciatica. The pain is less specific than sciatica in distribution and does not extend to the ankle or foot.

Answer 32

819. (A) A. and D. Although radicular symptoms often accompany low back pain during pregnancy, the incidence of herniated nucleus pulposus is only 1:10,000. The prevalence of lumbar intervertebral disk abnormalities is not increased in pregnant women. Direct pressure of the fetus on the lumbosacral nerves has been postulated as the cause of radicular symptoms. B. Back pain occurs at some time in about 50% of pregnant women and is so common that it is often looked on as a normal part of pregnancy. The lumbar lordosis becomes markedly accentuated during pregnancy and may contribute to the development of low back pain. C. Endocrine changes during pregnancy may also play a role in the development of back pain. Relaxin, a polypeptide secreted by the corpus luteum, softens the ligaments around the pelvic joints and cervix, allowing accommodation of the developing fetus and facilitating vaginal delivery. This laxity may cause pain by producing an exaggerated range of motion. E. The hormonal changes that occur during pregnancy lead to widening and increased mobility of the sacroiliac synchondroses and the symphysis pubis as early as the 10th to 12th weeks of pregnancy.

Answer 33

820. (C) A. Migraines occur more often during menstruation, because of decreased estrogen levels. During pregnancy, 70% of women report improvement or remission of migraines. B. and E. Migraine headaches rarely begin during pregnancy. Headaches that initially present during pregnancy should initiate a thorough search for potentially serious causes. Examples may include strokes, pseudotumor cerebri, tumors, aneurysms, atrioventricular malformations, and others. C. Patients presenting with their first severe headache should receive a complete neurologic examination, toxicology screen, serum coagulation profiles, and an MRI should be encouraged. In the patient who presents with “worst headache of my life,” subarachnoid hemorrhage should be ruled out. D. Progressively worsening of headaches in the setting of weight gain may be secondary to preeclampsia or pseudotumor cerebri. Preeclampsia has the triad of elevated blood pressure, proteinuria, and peripheral edema.

Answer 34

821. (E) A., B., C., and D. One of the most common causes of abdominal pain early in pregnancy is miscarriage, presenting with abdominal pain and vaginal bleeding. Ectopic pregnancy and ovarian torsion may present with hypogastric pain and suprapubic tenderness. Once these conditions have been ruled out, myofascial causes of abdominal pain should be considered. E. Sacroiliac joint pain or sacroiliac dysfunction usually does not presents with abdominal pain, but with low back pain that may radiate to the hip and thigh area.

Answer 35

822. (E) Opioids are excreted into breast milk. It has been shown that concentrations of morphine and codeine are equal to or greater than maternal plasma concentrations. The American Academy of Pediatrics considers use of many opioid analgesics including codeine, fentanyl, methadone, morphine, and propoxyphene to be compatible with breast-feeding.

Answer 36

823. (D) Perception of pain is influenced by prior experiences, expectations, and the cognitive capacity of the patient. The patient and family should be advised of the potential for pain and strategies to communicate pain. Patient selfreporting is the gold standard for the assessment of pain and the adequacy of analgesia. Pain assessment tools such as the visual analogue scale or numeric rating scale are most useful. The numeric rating scale may be preferable because it is applicable to many age groups and does not require verbal responses. In noncommunicative patients, assessment of behavioral (movements, facial expressions, posturing) and physiologic (heart rate, blood pressure, respiratory rate) indicators is necessary.

Answer 37

824. (A) A. Opioids are the mainstay of pain management in the ICU. Desired properties of an opiate include rapid onset of action, ease of titration, lack of accumulation of parent drug or active metabolites, and low cost. The most commonly prescribed opioids are fentanyl, morphine, and hydromorphone. Fentanyl has a rapid onset of action and short t1/2 and generates no active metabolites. It is ideal for use in hemodynamically unstable patients or in combination with benzodiazepines for short procedures. Continuous infusion may result in prolonged effect owing to accumulation in lipid stores, and high dosing has been linked to muscle rigidity syndromes. B., D., and E. Morphine has a slower onset of action (compared to fentanyl) and longer t1/2. It may not be suitable for hemodynamically unstable patients because associated histamine release may lead to vasodilatation and hypotension. An active metabolite can accumulate in renal insufficiency. Morphine can also cause spasm of the sphincter of Oddi, which may discourage its use in patients with biliary disease. Hydromorphone has a t1/2 similar to morphine but generates no active metabolites and no histamine release. All opioid analgesics are associated with varying degrees of respiratory depression, hypotension, and ileus. C. Alternatives to opioids include acetaminophen and NSAIDs. Ketorolac is the only available intravenous NSAID. It is an effective analgesic agent used alone or in combination with an opioid. It is primarily eliminated by renal excretion, so it is relatively contraindicated in patients with renal insufficiency. Prolonged (> 5 days) use has been associated with bleeding complications.

Answer 38

825. (E) Many benefits of epidural anesthesia have been reported, including better suppression of surgical stress, more stable hemodynamics, better peripheral circulation, and reduced blood loss. Aprospective, randomized study of 1021 abdominal surgery patients demonstrated that epidural opioid analgesia provides better postoperative pain relief compared with parenteral opioids. Furthermore, in patients undergoing abdominal aortic operations, overall morbidity and mortality were improved and intubation time and ICU length of stay were shorter.

Answer 39

826. (B) A large, multicenter, randomized investigation of epidural narcotics compared to parenteral narcotics performed in veterans affairs hospitals found that patients receiving epidural analgesia had better pain relief, shorter durations of intubation, and fewer ICU stays. In contrast, a multicenter trial in Australia that included both, men and women as well as very high-risk patients found that epidural analgesia had no effect on mortality or length of stay. Postoperative respiratory failure occurred significantly less frequently, however, in the patients receiving epidural analgesia. At a minimum, it appears that epidural analgesia can produce superior pain relief, particularly if it is initiated prior to the surgical incision, and it may be associated with fewer complications and a lower incidence of respiratory failure than parenteral narcotics in selected patients.

Answer 40

827. (C) A. Pain and other symptoms also may be poorly managed because they are subjective experiences that are not easily assessed by objective methods. Pain and sedation scales have been developed to quantify the levels of pain and anxiety among patients who can self-report. Nevertheless, some patients cannot adequately communicate these sensations, either because they cannot find the words or because they are intubated and sedated. To detect pain in these patients, physicians and other caregivers must attend to patient grimacing and other admittedly nonspecific manifestations of pain, including tachycardia and hypertension. B. Some patients value symptom relief highly and would prefer to be rendered unconscious rather than to experience pain, anxiety, or dyspnea, especially at the end of life. Others, however, would be willing to tolerate these symptoms or have them mitigated only slightly in order to stay awake. Dying patients may find it difficult to titrate sedatives and analgesics to their desired level of consciousness, although they should be encouraged to do so. Physicians and caregivers may find it even more difficult to achieve the ideal level of sedation and analgesia for patients who cannot communicate or administer drugs to themselves. C., D., and E. Symptoms may be inadequately managed because physicians and other caregivers feel uncomfortable about giving high doses of sedatives, analgesics, and other mood-altering agents. In some instances, this discomfort stems from a reluctance to cause drug addiction in dying patients, a phenomenon irrelevant to the patients’ condition.

Answer 41

828. (E) Pain can be managed indirectly by nonpharmacologic means. For example, placing patients in a quiet environment where friends and family can visit may diminish the sense of pain, as may the proper treatment of anxiety and depression. Although respiratory depression caused by drugs or underlying disease usually is undesirable in patients with COPD, the encephalopathy that results from the hypercapnia and hypoxia may be tolerated, if not favored, in terminal patients because it attenuates pain. Similarly, patients who forgo nutrition and hydration at the end of life may develop a euphoria that has been attributed to the release of endogenous opioids or the analgesic effects of ketosis.

Answer 42

829. (C) Adirect approach to pain control generally centers on the use of opioids, and morphine is the opioid most commonly used. In addition to causing analgesia, morphine induces some degree of sedation, respiratory depression, constipation, urinary retention, nausea, and euphoria. It also produces vasodilation, which may cause hypotension, in part through the release of histamine. Fentanyl, a synthetic opioid that is approximately 100 times more potent than morphine, does not release histamine and therefore causes less hypotension. Hydromorphone, a semisynthetic morphine derivative, is more sedating than morphine and produces little euphoria.

Answer 43

830. (A) Morphine, fentanyl, and hydromorphone can be administered orally, subcutaneously, rectally, or intravenously. Opioids usually are given by the IV route to ICU patients, including those who are dying. These agents may be administered to inpatients and outpatients alike through the technique of PCA. Longacting oral preparations of morphine and hydromorphone are available for outpatients. Fentanyl can be administered orally in the form of a lollipop. It can also be given by the transcutaneous route, which makes this agent particularly suitable for patients who have difficulty with oral medications.

Answer 44

831. (D) Many benefits of epidural anesthesia have been reported, including better suppression of surgical stress, more stable hemodynamics, better peripheral circulation, and reduced blood loss. Aprospective, randomized study of 1021 abdominal surgery patients demonstrated that epidural opioid analgesia provides better postoperative pain relief compared with parenteral opioids. Furthermore, in patients undergoing abdominal aortic operations, overall morbidity and mortality were improved and intubation time and ICU length of stay were shorter.

Answer 45

832. (A) Atelectasis is most often seen in postsurgical or immobilized patients. As alveoli collapse, there is increased shunting with resultant hypoxemia. Additional findings are related to the degree of atelectasis and include diminished breath sounds and reduced lung volume, elevated hemidiaphragm, or consolidation on chest radiography. Associated fever usually abates with reinflation, but the collapsed alveoli are prone to bacterial colonization with the development of pneumonia. Treatment is aimed at reexpansion of collapsed alveoli. Maintenance of airway patency and pulmonary toilet are of primary importance. Pain management is pivotal to balance splinting with sedation and hypoventilation. Pneumonia is common in the ICU, particularly among ventilated patients and those with direct lung injury. The clinical presentation involves fever, leukocytosis, hypoxia, a distinct radiographic infiltrate, and purulent sputum with bacterial colonization. Respiratory support, pulmonary toilet, and antibiotics are the fundamentals of treatment

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Chapter 10. Interdisciplinary Pain Management Flashcards

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