Lippincott's Anesthesia Review: 1001 Questions and Answers
Chapter 14. Gastrointestinal, Liver, and Renal Diseases
1. A 38-year-old woman with a history of diverticulosis is scheduled for an exploratory laparotomy for lysis of adhesions. Which of the following is the best way of maintaining core body temperature during the initial hour of general endotracheal anesthetic?
A. Providing warm and humidified inspired gases
B. Increasing ambient temperature
C. Administration of warm intravenous fluids
D. Use of warm irrigating fluids
2. Each of the following would be expected in an otherwise-healthy 125-kg (BMI 40 kg/m2) man undergoing open cholecystectomy, except
A. Decreased functional residual capacity
B. Increased intra-abdominal pressure and risk of reflux
C. Increased metabolism of volatile anesthetics
D. Decreased metabolism of atracurium
3. Which of the following has a dual effect of increasing gastric pH, and decreasing the gastric volume to minimize risks associated with aspiration?
4. This finding is indicative of microatelectasis on the second postoperative day after major abdominal surgery:
C. Diffuse wheezing
D. Tactile fremitus
5. A morbidly obese 60-year-old man with a 65-pack year history of tobacco smoking is awake after an uncomplicated general anesthetic with sevoflurane for routine endoscopy and colonoscopy screening. After 45 minutes in the recovery room (PACU), while breathing 6 L/min of oxygen via nasal cannula, his pulse oximetry drops to 88%. His rest of the vital signs are stable, and the lungs are clear to auscultation. The most effective management at this point is
A. Coughing with deep breathing
B. Reintubation of the trachea
C. Intravenous administration of doxapram
D. Continuous positive-airway pressure
6. During rapid-sequence induction of anesthesia for emergent laparotomy to explore multiple stab wounds, a 45-year-old man vomits a large quantity of undigested food particles. During intubation of the trachea, food particles are noted near the cords. After instituting ventilation with 100% oxygen, the most appropriate next step in this patient’s management is
A. Place patient in Trendelenburg position
B. Ventilate with positive end–expiratory pressure of 15 cm H2O
C. Administer corticosteroids
D. Administer antibiotics
7. A 71-year-old female develops a severe case of diarrhea with multiple loose bowel movements since awakening this morning. When she arrives preoperatively for her surgery, an arterial blood gas (ABG) is obtained. The most likely finding would be
A. pH = 7.30, PaCO2 = 50, PaO2 = 60, HCO3 − = 24
B. pH = 7.35, PaCO2 = 32, PaO2 = 85, HCO3 − = 18
C. pH = 7.45, PaCO2 = 30, PaO2 = 80, HCO3 − = 28
D. pH = 7.40, PaCO2 = 45, PaO2 = 85, HCO3 − = 15
8. A 65-year-old patient is noted to have excessive bleeding during a colectomy with an activated clotting time (ACT) of 200 seconds. The most unlikely reason for this oozing is
A. Undiagnosed factor VII deficiency
B. Prior administration of heparin 5,000 U subcutaneously
C. Preoperative ingestion of aspirin and ibuprofen
D. Dilutional thrombocytopenia
9. During laparotomy, a patient has required infusion of 4 L of lactated Ringer’s and 4 U of packed red blood cells (pRBCs). As the fifth unit of pRBCs begins infusing, patient has sudden onset of tachycardia and hypotension. Within a few minutes, Foley bag reveals dark urine. The most likely cause of unexplained oozing is
A. Hemolytic transfusion reaction
B. Leukoagglutinin reaction
C. Dilutional thrombocytopenia
D. Dilutional coagulopathy
Questions 10 to 12
A 26-year-old male patient with a history of severe ulcerative colitis, unresponsive to conservative measures, presents for elective open total abdominal colectomy with end ileostomy. He has been unable to eat for the last 2 weeks and was started on total parenteral nutrition (TPN) several days prior.
10. Intraoperative effect that should be expected and monitored for is
A. Dilutional anemia
11. At the conclusion of the surgery, the patient fails to regain consciousness. The metabolic complication of TPN (Table 14-1) that is likely is
Table 14-1 Metabolic Complications of TPN.
Glucose (hypoglycemia, hyperosmolar nonketotic coma)
Essential fatty acid deficiency
C. Hyperosmolar ketotic hyperglycemia
D. Hyperosmolar nonketotic hyperglycemia
12. Consider that the patient opens his eyes and is extubated in the operating room. However, 15 minutes after arriving to the recovery room (PACU) he is unable to maintain adequate ventilation and oxygenation. Physical exam reveals profound global weakness with absent reflexes. The specific electrolyte abnormality that should be evaluated considering his TPN requirement is
13. Each of the following statements about the preoperative management of an adrenal pheochromocytoma is true, except
A. Adequate blockade can be assessed by in-house blood pressures <160/90 mm Hg for 24 hours prior to surgery
B. β-Blockers should be administered only in conjunction with adequate α-blockade
C. Administration of α-blocker can decrease operative mortality
D. Nasal congestion is a sign of inadequate α-adrenergic block
14. A 40-year-old man undergoing an open resection of a pheochromocytoma under isoflurane general endotracheal anesthesia suddenly develops tachycardia, hypertension, and multifactorial ventricular ectopy. Each of the following could be considered an appropriate treatment option, except
A. Switching from isoflurane to sevoflurane
B. Intravenous vasodilator
C. Intravenous α-blocker
D. Intravenous lidocaine
15. An otherwise-healthy 38-year-old female patient is undergoing repair of a large ventral hernia under intrathecal anesthesia. A T2 sensory level is obtained with hyperbaric bupivacaine prior to incision. A false statement concerning this situation includes
A. Effective cough is preserved
B. The cardioaccelerator nerves are blocked
C. Examination of the biceps reveals full strength bilaterally
D. Bupivacaine binds to the intracellular portion of sodium channels
16. A patient with cholestasis presents for preoperative evaluation with laboratory findings revealing normal aspartate aminotransferase (serum glutamic–oxaloacetic transaminase) and prothrombin time but with a markedly elevated alkaline phosphatase. He will need a muscle relaxant for upcoming colon surgery. Which of the following anesthetic scenarios should be considered?
A. Prolonged duration of vecuronium action
B. Increase intubating dose of atracurium
C. Prolonged duration of succinylcholine action
D. Shortened duration of pancuronium action
17. An alcoholic 62-year-old male patient is noted to have jaundice one day after a laparoscopic cholecystectomy under halothane/fentanyl general endotracheal anesthesia. Bilirubin and alkaline phosphatase are elevated, but alanine aminotransferase (serum glutamic–pyruvic transaminase [SGPT]) and aspartate aminotransferase (serum glutamic–oxaloacetic transaminase [SGOT]) are within normal ranges. Of note, all values were within normal limits in this patient preoperatively. The most likely cause of his jaundice is
A. Idiopathic halothane hepatic injury
B. Worsening of underlying chronic liver dysfunction
C. Posthepatic biliary obstruction
D. Intravenous acetaminophen administration
18. An initial bolus of pancuronium was administered to a patient with end-stage liver disease with associated ascites for general anesthesia. Appropriate anesthetic considerations include all of the following, except
A. Increased sympathomimetic activity due to vagolysis
B. Intense histamine release immediately after administration
C. Larger volume of distribution requiring initial larger doses
D. Longer duration of action requiring smaller maintenance doses
19. A chronic alcoholic patient with liver cirrhosis is likely to demonstrate all of the following during administration of anesthesia, except
A. A high minimum alveolar concentration (MAC) for desflurane
B. Opioid hyperalgesia
C. Resistance to the hypnotic effects of thiopental
D. Resistance to the analgesic effects of opiates
20. A woman with long-standing alcoholic cirrhosis (Child-Turcotte-Pugh B) presents to the emergency room for chronic shortness of breath and abdominal pain. A review of her lab findings reveal a hematocrit concentration of 36% (hemoglobin 12.4 g/dL) with an arterial blood gas revealing a PaO2 of 65 mm Hg breathing a FIO2 of 0.5 via face mask. Her vitals are a blood pressure of 135/60 mm Hg and a heart rate of 88 bpm. The most likely cause of her hypoxemia is
A. Intrahepatic arteriovenous shunts
B. Intrapulmonary arteriovenous shunts
D. Decreased cardiac output
21. Which of the following cardiovascular abnormalities is least likely to be present in a patient with end-stage alcoholic cirrhosis
A. Resting tachycardia
B. Widened pulse pressure
C. Increased peripheral vascular resistance
D. Increased cardiac output
Questions 22 to 23
A 120-kg diabetic male is scheduled for emergent pinning of his mandible after a motor vehicle accident. His wife reports that he snores loudly every night with occurrences of breathing cessation. Medical history is also significant for hypertension controlled with a diuretic. On physical examination, he has a large tongue and a wide neck with inadequate mouth opening revealing a Mallampati grade 4 view. His BMI is 38 kg/m2 with a neck circumference of 44 cm.
22. Arterial blood gas (ABG) finding that would confirm Pickwickian syndrome is
A. pH = 7.44, PaCO2 = 44, PaO2 = 90, HCO3 = 24
B. pH = 7.35, PaCO2 = 44, PaO2 = 65, HCO3 = 26
C. pH = 7.42, PaCO2 = 36, PaO2 = 80, HCO3 = 22
D. pH = 7.37, PaCO2 = 55, PaO2 = 67, HCO3 = 28
23. The dose of thiopental required for rapid-sequence induction would be increased, as compared with what would be required at his ideal body weight, because of changes in
A. Decreased basal metabolic rate
B. Increased blood volume
C. Increased muscle mass
D. Decreased liver metabolism
24. A patient with chronic liver disease is scheduled for a laparoscopic abdominal operation. The risk of mortality during surgery for this patient is assessed using
A. Mayo end-stage liver disease
B. Child-Turcotte-Pugh score
C. Ranson criteria
D. Alvarado score
25. The variable not used to calculate an MELD (model for end-stage liver disease) score to prioritize patients for liver transplantation is
B. INR (international normalized ratio)
Questions 26 to 28
A 30-year-old male patient without preoperative renal dysfunction is undergoing a primary orthotopic liver transplant (OLT) for failure due to inherited α1-antitrypsin deficiency.
26. During cross-clamping of the suprahepatic inferior vena cava (IVC), the most accurate effect created by use of venovenous bypass (VVB) is that it
A. Induces urinary retention
B. Prevents metabolic acidosis
C. Requires heparinization
D. Supports cardiac output
27. Immediately before unclamping and reperfusion of the transplanted liver, sodium bicarbonate and calcium chloride are administered intravenously to counteract
B. Decreased cardiac output
C. Increased systemic vascular resistance
28. At the end of the case as the drapes are taken down, diffuse microvascular bleeding is noted in this patient who required 15 U of blood during his intraoperative course. Platelet count is 40,000/mm3, prothrombin time is 18 seconds, activated partial thromboplastin time (PTT) is 54 seconds, D-dimer is 2,000 ng/mL, and serum fibrinogen concentration is 40 mg/dL. The most likely cause of bleeding is
A. Disseminated intravascular coagulation (DIC)
B. Abnormal platelet function
C. Depressed levels of factor VIII
D. Citrate toxicity
29. A patient presents for preoperative evaluation for upcoming surgery. He has a history of liver transplantation 2 years ago, otherwise feeling well. Which of the following is most likely to be present during preoperative evaluation?
A. Elevated serum creatinine concentration
C. Prolonged partial thromboplastin time
30. Following a gastric bypass procedure, a 130-kg woman is extubated and breathing spontaneously in the recovery room (PACU). She is breathing at a rate of 24 breaths/min on 10 L/min of oxygen via nasal cannula, and is complaining of continued subjective dyspnea. Arterial blood gas analysis shows PaO2 = 95 mm Hg, PaCO2 = 44 mm Hg, and pH = 7.37. The parameter most closely related to her increased alveolar–arterial oxygen-tension gradient is
A. Decreased minute volume
B. Decreased functional residual volume
C. Decreased expiratory reserve volume
D. Decreased respiratory drive
31. During laparoscopic cholecystectomy, the risk of failure to visualize contrast material entering the duodenum during intraoperative cholangiogram is highest with the administration of
32. Drugs that can decrease or reduce opioid-induced biliary spasm include all of the following, except
33. Each of the following is associated with delayed gastric emptying, except
A. Diabetes mellitus
B. Celiac plexus block
D. μ-Receptor agonism
Questions 34 to 39
A 33-year-old otherwise-healthy female suffering from moderately severe abdominal pain of unclear etiology is set to undergo an exploratory laparoscopy. The abdominal cavity is insufflated using carbon dioxide (CO2).
34. All of the following are correct statements regarding pathophysiologic changes associated with creation of the pneumoperitoneum, except
A. Increased risk of reflux and aspiration
B. Decreased venous return
C. Decreased systemic vascular resistance (SVR)
D. Increased intrathoracic pressures
35. Inherent risks of abdominal laparoscopy include
A. Renal failure
C. Gas emboli
36. The patient is placed in a steep Trendelenburg position. Her oxygen saturation begins to gradually decline over the course of several minutes while being ventilated with 100% oxygen (FIO2 = 1.0). The initial step in the management of her hypoxemia is
A. Add positive end–expiratory pressure (PEEP)
B. Intravenous bolus of 500 mL saline
C. Reposition the patient
D. Switch to pressure support ventilation
37. The exploratory surgery progresses slowly. Over the next 3 hours, her EtCO2 begins to gradually rise, requiring increasing minute ventilation. All of the following contribute to the degree of systemic CO2 absorption, except
A. Solubility of the gas
B. Intra-abdominal pressures (IAP)
C. Duration of surgery
D. Blood pressure
38. Each of the following is hemodynamic change associated with hypercarbia, except
C. High cardiac output
D. Low systemic vascular resistance (SVR)
39. The surgery continues on with a request to increase the pneumoperitoneum to 30 mm Hg to improve the surgical view. All of the following are appropriate in the differential diagnosis for hypotension during laparoscopy, except
A. Compression of the inferior vena cava
B. Increase cardiac afterload
C. Too small blood pressure cuff
D. CO2 embolism
40. This physical exam finding is inappropriately paired with the possible nerve injury resulting from ill positioning during surgery:
A. Inability to evert the foot
common peroneal nerve
B. Inability to stand on toes
C. Difficulty climbing stairs
femoral nerve injury
D. Foot drop
saphenous nerve injury
41. A 50-year-old male patient is to undergo an open nephrectomy for renal carcinoma. The patient requests an epidural for perioperative pain management, as he is strongly intolerant to μ-agonist opiate therapy with nausea and vomiting. After a T2 sensory level is obtained, the patient is induced with propofol 200 mg and rocuronium 70 mg, followed by tracheal intubation. The expected response to intubation in this patient includes
42. A 24-year-old female status postrecent living-related renal transplant requires chronic immunosuppression with cyclosporine and steroids to combat organ rejection. She now presents for right-knee arthroscopic anterior cruciate ligament repair and mentions significant history of postoperative nausea and vomiting (PONV). The most appropriate next step in planning her anesthetic management is
A. Proceed with total IV anesthesia (TIVA), avoiding inhaled anesthetics
B. Avoid regional anesthesia
C. Liberally infuse intravenous fluids
D. Use metoclopramide to decrease gastric secretions
Questions 43 to 45
A 70-year-old 70-kg male with benign prostatic hypertrophy and difficulty with urination presents for a transurethral resection of his 65-g prostate (TURP). His other pertinent history includes hypertension and hyperlipidemia, both well controlled. He has a remote history of a lumbar spinal fusion with no current lumbar symptomatology. The patient requests a general anesthetic for the procedure and refuses spinal anesthesia.
43. Assuming the use of a hypotonic irrigant, these factors will contribute to the amount of fluid absorbed by the patient, except
A. Venous pressure
B. Hydrostatic pressure of the irrigation infusion
C. Lithotomy position
D. Size of prostate
44. In the recovery room, he complains of bothersome localized suprapubic pain and is requesting pain medicine. He denies pain or discomfort anywhere else. His review of systems is negative for fevers or chills. The relatively common complication of this procedure that should be ruled out at this time is
B. Glycine toxicity
C. Extraperitoneal perforation
D. Transient bacteremia
45. The patient is administered hydromorphone intravenously, and 20 minutes later is feeling well with minimal pain complaints. At this time, his postoperative laboratories have returned, revealing a serum sodium value of 130 mEq/L. The most appropriate next step in the management of his hyponatremia is
A. Hypertonic saline infusion
B. Fluid restriction
C. Demeclocycline administration
D. Insulin and glucose administration
46. Effects of furosemide administration in the perioperative period include
B. Decreased risk for acute tubular necrosis
C. Metabolic alkalosis
Questions 47 to 51
A 38-year-old woman is set to undergo extracorporeal shock wave lithotripsy to disintegrate a painful stone trapped in her upper ureter. The patient is requesting an epidural anesthetic and is choosing to be otherwise awake and cooperative with her positioning and procedure.
47. The step of the epidural placement that should be avoided in this patient is
A. Loss of resistance to air
B. Loss of resistance to hanging drop
C. Test dose injection
D. Bolus dose of local anesthetics
48. Once the epidural is adequately placed and the patient is immersed sitting in the water tank, the physiologic change that should be expected is
A. Decreased central venous pressure
B. Increased vital capacity
C. Increased functional residual capacity
D. Lower extremity peripheral pooling
49. Extracorporeal shock wave lithotripsy therapy proceeds with the shock wave synchronized with what ECG phase of the cardiac cycle?
A. The P wave
B. The Q wave
C. The R wave
D. The S wave
50. Which of the following statements would be considered false with regard to extracorporeal shock wave lithotripsy (ESWL)?
A. Delivery of the shock wave is timed to coincide with the ventricular refractory phase
B. Neuraxial anesthesia up to T2 sensory level is adequate
C. If able to control ventilation, use high tidal volumes and low respiratory rate
D. Removal of the patient from the bath water can be accompanied by a decrease in the blood pressure
51. All of the following are contraindications to immersion extracorporeal shock wave lithotripsy, except
A. Harrington rod implants
B. Abdominally placed rate-responsive cardiac pacemaker
C. Positive pregnancy test
D. Large calcified abdominal aortic aneurysm
52. Which of the following is considered the most sensitive indicator of impending traumatic renal failure?
A. Decreased creatinine clearance
B. Decreased central venous pressure
C. Decreased fractional excretion of sodium
D. Increased urine osmolality
53. A 26-year-old male patient with Alport syndrome requires hemodialysis (every third day) and presents for an arteriovenous fistula creation. His last dialysis treatment was yesterday. Patient requests general anesthesia for this procedure. Which of the following drugs will have a prolonged duration of action?
54. Each of the following is associated with acute tubular necrosis, except
A. Hyaline casts
B. Urine specific gravity <1.010
C. Muddy casts
D. Fractional excretion of sodium of 4%
Questions 55 to 56
A 75-year-old patient who is awaiting urgent laparotomy has had oliguria for the past 12 hours since the onset of his acute abdominal pain last night. His medical history includes well-controlled hypertension. Vital signs include a BP of 120/65 mm Hg and a HR of 72 bpm. His laboratory findings reveal
Urine osmolality: 550 mOsm/L
Urine specific gravity: 1.020
Urine sodium concentration: 15 mmol/L
Fractional excretion of sodium: 0.5%
Ratio of urine-to-plasma urea concentration: 10
55. The most appropriate treatment of his oliguria is
A. Fluid restriction
B. Fluid challenge
C. Renal ultrasound
D. Foley placement
56. Fluid resuscitation is done with 4 L of normal saline. The potential acid–base abnormality that can occur is
A. Hyperchloremic acidosis
B. Metabolic alkalosis
C. Hyperkalemic acidosis
D. Respiratory alkalosis
57. A 67-year-old patient with chronic renal failure presents for hip arthroscopy to address and treat his labral tears and associated hip pain. The best option for opioid therapy in this patient is
CHAPTER 14 ANSWERS
1. B. The initial reduction in core temperature during general anesthesia is caused by redistribution of heat from the core to the periphery, which can be attenuated by increasing ambient temperature to minimize the gradient.
2. D. Perioperative morbidity related to obesity is associated with changes in respiratory (e.g., difficult airway, decreased functional residual capacity), cardiovascular (e.g., increased cardiac output), and gastrointestinal (e.g., gastroesophageal reflex disease, increased abdominal pressure) systems that will impact the delivery of anesthesia. Given that metabolism of inhalational agents is increased over normal weight patients, higher minimum alveolar concentrations may be required. Atracurium (including cis-atracurium) is metabolized via Hofmann degradation and is unaffected by the obese state.
3. B. Aspiration of acidic gastric juices poses a potential threat during induction and intubation. H2-blockers (e.g., cimetidine, ranitidine) can decrease gastric volume and raise pH to a level that should be protective from fatal aspiration. Metoclopramide promotes gastrointestinal motility without directly affecting pH itself. 5-HT3 (serotonin) receptor antagonism (e.g., ondansetron) and D2 (dopamine) antagonism (e.g., prochlorperazine) are useful antiemetics, with no effect on gastric pH or volume.
4. B. Atelectasis likely occurs in all patients who undergo general anesthesia, in particular those postabdominal surgeries. Changes of microatelectasis develop routinely and do not significantly delay discharge for most patients despite the relative state of hypoxia (decreased PaO2). Deep breathing, use of an incentive spirometer, early mobilization, and adequate pain control are all measures used to expand lung volumes and promote improved oxygenation.
5. A. Postsurgical atelectasis is treated by physiotherapy, focusing on deep breathing while encouraging coughing. An incentive spirometer is often used to promote full expansion of the lungs. Ambulation is also highly encouraged to improve lung inflation. These measures are considered first-line options for his presumed microatelectasis. In the smoker, coughing will also clear the airways of mucous to improve aeration. Doxapram stimulates chemoreceptors in the carotid bodies, which in turn stimulates the respiratory center in the brain stem to increase tidal volume and respiratory rate.
6. A. Initial management involves the recognition of a possible aspiration event when there are visible gastric contents in the oropharynx. Once diagnosis is suspected, the patient should be placed in Trendelenburg position to limit pulmonary contamination, followed by suctioning of the oropharynx. Empirical antibiotic therapy is strongly discouraged unless it is apparent that the patient has developed a subsequent pneumonia. Corticosteroids should not be given prophylactically, as there is no evidence to support this practice.
7. B. Gastrointestinal secretions, including diarrhea and intestinal fistulas, are rich in bicarbonate and, therefore, losses will cause a metabolic acidosis. However, respiratory compensation for metabolic processes will occur almost immediately by increasing ventilation to blow off CO2 to reduce the acidosis, effecting change in as quick as 15 to 30 minutes. Therefore, one would expect ABG findings of a metabolic acidosis with full respiratory compensation.
8. A. The ACT enables one to monitor the anticoagulant effect of unfractionated heparin. ACT prolongation can also indicate coagulation-factor deficiency, severe thrombocytopenia, or severe platelet dysfunction. The ACT is sensitive to a deficiency or dysfunction of all the clotting factors (except factor VII)—indicating problems with the intrinsic or common pathways. Factor level must be less than 5% of normal to prolong the ACT.
9. A. An acute hemolytic transfusion reaction is associated with hemolysis of transfused blood, usually related to ABO incompatibility with associated hemoglobinuria. Pulmonary leukoagglutinin reaction is related to the presence of antileukocyte antibodies in donor plasma leading to transfusion-related acute lung injury.
10. B. Malnourished surgical patients are at greater risk for postoperative morbidity and mortality compared to a well-nourished patient undergoing similar operations for similar indications. However, providing TPN to the malnourished patient in the perioperative period carries its own inherent risks, such as greater risk of infection, hyperglycemia, and electrolyte abnormalities.
11. D. For those on TPN, the anesthesiologist must monitor blood glucose levels meticulously to avoid hypo- or hyperglycemia. Hyperosmolar, nonketotic, hyperglycemic coma has been reported in patients who fail to regain consciousness after anesthesia.
12. B. Ensuring the presence of normal serum phosphate levels in the patient receiving TPN is essential, as hypophosphatemia has been associated with acute respiratory failure due to profound areflexic muscle weakness.
13. D. The most critical element to safe perioperative care of the pheochromocytoma patient is adequate preoperative blockade against the effects of the circulating catecholamines. The main goals of preoperative blockade are to normalize blood pressure and heart rate, restore volume depletion, and prevent surgery-induced catecholamine storm. A sign of adequate α-blockade is the development of nasal congestion due to smooth-muscle relaxation of nasal mucosal arterioles.
14. A. Switching from isoflurane to sevoflurane is not an appropriate method to treat the catecholamine storm, which can occur during direct surgical manipulation of the tumor. An α-blocker, vasodilator, and lidocaine are appropriate options to counter the effects of catecholamine storm.
15. A. Sympathetic preganglionic fibers originate in the intermediolateral cell column of the spinal cord from T1 to L2. Cardiac innervation is principally via sympathetic fibers from T1 to T4. As such, high thoracic blockade up to T2 will block the cardioaccelerator nerves, leading to bradycardia and hypotension. The respiratory system is usually unaffected, as diaphragmatic breathing alone can maintain relatively normal arterial blood gases. However, patients may feel unable to breath and are often unable to cough effectively.
16. A. The pharmacokinetics of many nondepolarizing muscle relaxants in the presence of cholestasis and obstructive jaundice may be altered. The prolonged duration of action likely results from both inhibition of hepatic uptake by the accumulated bile salts and a general deterioration of liver transport function. Succinylcholine, atracurium, and cis-atracurium have theoretical advantages because their elimination occurs via plasma cholinesterases and Hofmann degradation, respectively, mostly independent of renal or hepatic function.
17. C. Postoperative liver dysfunction is common, but is generally mild and asymptomatic (Table 14-2). Mild transient increases in serum levels of liver enzymes (SGOT/SGPT) are often seen within hours of surgery, but rarely persist >2 days. Subclinical hepatocellular injury can occur in up to 50% of those receiving an inhaled anesthetic with halothane. Though volatile anesthetics are often implicated as the cause of postoperative jaundice, there are many other causes to consider. A surgical cause is likely if the operation involved the liver or biliary tract. Drugs, including antibiotics, and other metabolic or infectious causes must also be ruled out.
Table 14-2 Postoperative Liver Dysfunction—Causes and Differentiation.
18. B. Chronic liver disease may interfere with the metabolism of drugs due to decreased number of functional hepatocytes or decreased hepatic blood flow that typically accompanies cirrhosis of the liver. Prolonged elimination half-life times for morphine, diazepam, lidocaine, pancuronium, and, to a lesser degree, vecuronium have been demonstrated in this population. Cirrhotic patients will require a larger initial dose of pancuronium due to increased volume of distribution for this hydrophilic agent with smaller maintenance doses for prolonged duration of action. Pancuronium has slight vagolytic activity resulting in increased heart rate and cardiac output. Mivacurium and atracurium are associated with histamine release.
19. B. Certain physiologic and pathologic states may alter MAC of inhaled anesthetics. MAC is higher in infants and lower in the elderly. Also, MAC increases with hyperthermia, alcoholism, and thyrotoxicosis. Furthermore, hypothermia, hypotension, and pregnancy seem to decrease MAC, while duration of anesthesia, gender, height, and weight seem to have little effect on MAC. Those with chronic liver disease are also at increased risk of arterial–venous shunting.
20. B. Those with chronic liver disease are at increased risk of arterial–venous shunting. The presence of intrapulmonary shunting will result in hypoxemia.
21. C. Cirrhosis is typically associated with several cardiovascular abnormalities including a hyperdynamic circulation characterized by increased cardiac output and decreased peripheral resistance. Other cardiovascular changes include a resting tachycardia, warm peripheries, a bounding pulse, and a widened pulse pressure.
22. D. Obesity hypoventilation syndrome (aka Pickwickian syndrome) is a state in which the severely overweight patient fails to breathe rapidly or deeply enough, resulting in hypoxia and hypercarbia. If Pickwickian syndrome is suspected, the most important initial test is the demonstration of elevated carbon dioxide in the blood. This requires either an ABG or a measurement of bicarbonate levels in venous blood. Expected ABG findings would reveal a chronic, compensated respiratory acidosis.
23. B. Redistribution of thiopental to inactive tissue sites rather than metabolism is the most important determinant of early awakening following a single intravenous injection.
24. B. The Child-Turcotte-Pugh score is used to predict mortality during surgery in patients with chronic liver disease, namely, cirrhosis. The Mayo or model for end-stage liver disease was initially developed to predict death within 3 months of surgery in patients who had undergone a transjugular intrahepatic portosystemic shunt procedure and was subsequently found to be useful in determining prognosis and prioritizing patients for liver transplant. Alvarado score is used for appendicitis, while the Ranson criteria assess pancreatitis.
25. D. The MELD score is a formulaic calculation utilizing three variables: creatinine, INR, and bilirubin. For dialysis-dependent patients, the creatinine score is automatically set to 4 mg/dL despite true serum levels.
MELD score = 10 × [0.957 × log e (creatinine) + log e (bilirubin)
+ 1.12 × log e (INR)] + 6.43
26. D. Standard technique of OLT causes changes in hemodynamics during the anhepatic phase because of cross-clamping of the suprahepatic IVC. Interruption of the IVC and portal vein flow causes a decrease in preload, cardiac output, and arterial blood pressure. VVB has been used to achieve hemodynamic stability by avoiding venous congestion, promoting venous return with decrease incidence of renal dysfunction.
27. B. Postreperfusion syndrome is the most common hemodynamic derangement in liver transplantation, manifesting mainly as decreased heart rate, mean arterial pressure, and systemic vascular resistances. Ventricular function, both right and left, has been shown to be normal during reperfusion, in which case the visceral and liver vasodilation that occurs would be the main cause of arterial hypotension. Prophylaxis with atropine prevents bradycardia but not hypotension. Administration of calcium chloride and sodium bicarbonate together with hyperventilation mitigates the symptoms related to the reduced cardiac output.
28. A. Coagulopathy following massive transfusion is a consequence of posttraumatic and surgical hemorrhage. Bleeding following massive transfusion can occur due to hypothermia, dilutional coagulopathy, platelet dysfunction, fibrinolysis, or hypofibrinogenemia. Transfusion of 15 to 20 U of blood products causes dilutional thrombocytopenia contributing to the bleeding. Excessive fibrinolysis and low fibrinogen are further causes of bleeding in these patients. The hemostatic signatures of DIC are low platelets, low fibrinogen, prolonged prothrombin, prolonged PTT, elevated D-dimers, and low antithrombin.
29. A. Long-standing insufficient liver function is believed to cause changes in the circulation that changes vessel tone and blood flow in the kidneys. The likely presence of renal insufficiency is a consequence of these changes in blood flow, rather than direct damage to the kidney itself.
30. C. Dyspnea is a common complaint in individuals with class II or III obesity, especially following a general anesthetic. As such, individuals present with a pronounced reduction in expiratory reserve volume and an increase in the alveolar–arterial oxygen gradient.
31. C. μ-Receptor agonism may contribute to sphincter of Oddi spasm, preventing passage of contrast with full μ-agonist more likely to contribute versus partial μ-agonists (e.g., buprenorphine) and agonist–antagonist (e.g., nalbuphine). Naloxone, as a μ-antagonist would alleviate any opioid-induced spasm.
32. C. A variety of agents that can produce smooth-muscle relaxation have been used. Nitrates and calcium channel blockers have been the most extensively studied. Anticholinergics, including atropine and glucagon, are additional agents that can provide sphincter of Oddi relaxation. Metoclopramide is a promotility agent that enhances sphincter smooth-muscle contraction.
33. B. Sympathetic celiac plexus blockade leaves parasympathetic fibers unopposed with associated increased gastrointestinal motility and possible diarrhea.
34. C. Abdominal laparoscopy requires insufflation of the abdominal cavity, most commonly using CO2, to create a pneumoperitoneum. Increase in intra-abdominal pressures will place the patient at a greater risk of reflux and aspiration; thus, general anesthesia with an endotracheal tube is required. High pressures in the abdominal cavity can also compress both small and large blood vessels, hampering venous return to the heart. Intrathoracic pressures are also increased, associated with diaphragm elevation, compromising cardiac output further. Increase in SVR occurs during pneumoperitoneum, reflected as an increase in afterload for left-sided heart chambers.
35. C. Abdominal laparoscopy, though relatively safe, is associated with a few inherent dangers including gaseous embolism, potential inability to control bleeding, an increase in CO2 partial pressures and changes in arterial blood pressure and heart rate. CO2 absorption from the peritoneal cavity can result in a state of acidosis as PaCO2 rises.
36. A. The supine position under general anesthesia results in a decrease in functional residual capacity (FRC). Pneumoperitoneum and the Trendelenburg position shifts the diaphragm cephalad, further decreasing FRC. If FRC becomes less than closing capacity, airway collapse, atelectasis, and ventilation/perfusion mismatch can further compromise respiratory function. The judicious use of PEEP can be helpful to mitigate end-expiratory alveolar collapse; however, too much PEEP can contribute to deterioration in right-sided cardiac performance.
37. D. Systemic absorption of gas from pneumoperitoneum is determined by factors including solubility of the gas, IAP, and duration of surgery. Therefore, CO2 laparoscopy may produce hypercarbia, particularly during long surgeries under high IAP unless minute ventilation is increased. In those with severely compromised cardiopulmonary function and restricted CO2 clearance, severe hypercarbia can occur despite aggressive hyperventilation.
38. B. Hypercarbia causes hemodynamic changes by its direct action on the cardiovascular system and indirect actions through the sympathetic nervous system. Manifestations while under general anesthesia include tachycardia, arrhythmias, high cardiac output, increased arterial blood pressure, and low SVR with flushed skin.
39. C. The effects of pneumoperitoneum include compression of the inferior vena cava resulting in poor venous return and low preload. Systemic vascular resistance increases proportionately when the intra-abdominal pressure is elevated, providing a larger afterload against which the left ventricle must function. During insufflation, a gas embolus can occur, entering the venous system to create an “air lock” with mechanical obstruction of the right-side chambers. A blood pressure cuff that is too small for the arm will result in erroneously high blood pressure readings.
40. D. The saphenous nerve is the largest and longest branch of the femoral nerve that supplies sensory innervation to the medial aspect of the lower leg. Movement of the foot is unaffected.
41. D. High thoracic epidural blockade up to T2 blocks the cardiac accelerators, providing adequate sympathectomy to prevent hypertension and tachycardia. Sympathetic outflow to the pupil travels via the intermediolateral cell column at the C8 to T2 cord level and remains intact; thus, the sympathetic surge can still result in mydriasis.
42. A. Transplant recipients are always under various regimens of immunosuppression to prevent organ rejection. Clinically significant reductions in serum levels of these medications can be caused by dilution with massive fluid resuscitation perioperatively, as well as with cardiopulmonary bypass. Many immunosuppressants are metabolized in the liver via the cytochrome P450 system such that drugs administered during anesthesia (or perioperatively) may affect blood levels including increased concentrations with cimetidine and metoclopramide and decreased levels with octreotide. Regional anesthesia and/or TIVA are reasonable options to minimize PONV in this patient.
43. C. Normally, about 20 mL/min of irrigation fluid is absorbed (1–1.5 L for a normal case with resection time about 45–60 minutes), which increases as the duration of the surgery increases. In clinical practice, it is almost impossible to accurately assess the volume absorbed. The amount of fluid absorbed depends on several other factors as well, including the hydrostatic pressure of the irrigation infusion (determined by the height of the bag), venous pressure (more fluid absorbed if patient is hypotensive), the size of the prostate to be resected (associated with longer time required), blood loss (implies a large number of open veins), and surgical skills of the surgeon (efficiency with time management and hemostasis).
44. C. Another relatively common complication of TURP is perforation of the bladder. Perforations usually occur during difficult resections and are often made by the cutting loop or knife electrode. The tip of the resectoscope can also cause injury, as well as overdistention of the bladder with irrigation fluid. Most perforations are extraperitoneal, and in the awake patient, they result in pain in the periumbilical, inguinal, or suprapubic regions; additionally, the urologist may note the irregular return of irrigating fluid. Less often, the perforation is through the wall of the bladder and thus intraperitoneal. In such cases, pain may be generalized, in the upper abdomen, or referred from the diaphragm to the shoulder. Bacteremia is usually asymptomatic and easily treated with commonly used antibiotic combinations that are effective against gram-positive and gram-negative bacteria.
45. B. For normovolemic, asymptomatic hyponatremic patients, free water restriction is generally the treatment of choice. There is no role for hypertonic saline in these patients. The volume of restriction should be based on the patient’s renal diluting capacity. If patient is unable to adhere to fluid restrictions, consider use of a loop diuretic (e.g., furosemide) to increase free water excretion in the kidneys. Demeclocycline is a tetracycline antibiotic that has a secondary effect of reducing the responsiveness of the collecting tubule cells to antidiuretic hormone, thus improving free water loss.
46. C. As with many diuretics, furosemide can cause dehydration and electrolyte imbalance, including loss of potassium, calcium, sodium, and magnesium. Excessive use of furosemide will most likely lead to a metabolic alkalosis due to hypochloremia and hypokalemia.
47. A. With epidural anesthesia, consider avoiding the use of loss of resistance to air for identifying the epidural space, as air will provide an interface and cause dissipation of shock wave energy resulting in local tissue injury. Animal experiments have shown epidural tissue damage following injection of air followed by exposure to shock waves.
48. D. Water immersion produces significant changes in the cardiovascular and respiratory systems. Cardiovascular changes include an increase in central blood volume, with an increase in central venous and pulmonary artery pressures, which are directly correlated with the depth of immersion. The sitting position, together with either general or epidural anesthesia, would tend to cause peripheral pooling and decreased venous return. Respiratory changes with immersion up to the clavicles are significant: functional residual capacity and vital capacity are reduced by 20% to 30%; pulmonary blood flow has been shown to increase; and tight abdominal straps and the hydrostatic pressure of water on the thorax impart a characteristic of shallow, rapid breathing pattern.
49. C. Shock wave–induced cardiac arrhythmias occur in up to 10% to 14% of patients undergoing lithotripsy despite the fact that shock waves are purposefully synchronized with the patient’s ECG and are delivered in the refractory period of the cardiac cycle (R wave).
50. C. An advantage of providing a general anesthetic for ESWL is that ventilatory parameters can be controlled using high frequency and low volumes to decrease stone movement with respiration.
51. A. Contraindications for lithotripsy include the following: pregnancy, a large aortic aneurysm, certain bleeding conditions, and certain skeletal deformities that prevent accurate focus of shock waves. Patients with abdominally placed cardiac pacemakers should notify their doctor. Rate-responsive pacemakers that are implanted in the abdomen may be damaged during lithotripsy. Orthopedic prostheses, including hip prostheses and even Harrington rods, are generally not a problem as long as they can be kept out of the blast path.
52. A. Creatinine clearance test evaluates how efficiently the kidneys clear creatinine from the blood. Creatinine, a waste product of muscle energy metabolism, is produced at a constant rate that is proportional to the muscle mass of the individual. Because the body does not recycle it, all of the creatinine filtered by the kidneys in a given amount of time is excreted in the urine, making creatinine clearance a very specific measurement of kidney function.
53. B. Succinylcholine, atracurium, and cis-atracurium have theoretical advantages because their elimination occurs via plasma cholinesterases and Hofmann degradation, respectively, mostly independent of renal or hepatic function. Fentanyl and methadone are also considered relatively safe in renal failure as they have no active metabolites. Methadone has limited plasma accumulation in renal failure as it is primarily eliminated in the feces. In terms of reversal agents, renal excretion accounts for approximately 50% of the clearance of neostigmine and approximately 75% of elimination of edrophonium and pyridostigmine. Renal failure allows some protection against residual neuromuscular blockade because renal elimination half times of anticholinesterase drugs is prolonged.
54. A. Acute tubular necrosis is classified as a “renal” (e.g., not prerenal or postrenal) cause of acute kidney injury. Diagnosis is made by a fractional excretion of sodium >3%, greater than expected urine sodium concentration with low osmolality and presence of muddy casts on urinalysis. A sensitive indicator of tubular function is sodium handling because the ability of an injured tubule to reabsorb sodium is impaired, whereas an intact tubule can maintain this resorptive capacity. If the patient has tubular damage for any reason, the urinary sodium will be greater than expected. Keep in mind that the use of diuretics, however, can complicate the interpretation of these results. Low urine flow, concentrated urine, or an acidic environment can contribute to the formation of hyaline casts, pointing to hypovolemia and prerenal failure (Table 14-3).
Table 14-3 Differentiation between Prerenal and Intrinsic Renal Failure.
ACUTE TUBULAR NECROSIS
Urine Na+ (meq/L)
Urine osmolality (mOsm/kg)
Urine specific gravity
Urine:plasma urea ratio
55. B. Urinalysis reveals a prerenal state. Treatment focuses on correcting the cause of the prerenal acute renal failure, most often with a fluid challenge. Depending on the cause, the condition often reverses itself within a couple of days after normal blood flow to the kidneys has been restored. But if it is not reversed or treated successfully and quickly, prerenal acute renal failure can cause tissue death in the kidneys and lead to intrinsic (intrarenal) acute renal failure.
56. A. Hyperchloremic acidosis is a well-recognized entity as a consequence of large volume administration of some intravenous fluids. Normal saline (0.9% sodium chloride solution) and colloids suspended in normal saline are often infused because they are easily available, and are isotonic with plasma. When a patient is given normal saline (a hyperchloremic solution), chloride levels can significantly increase. It is the chloride anion that is the ultimate cause of the acidosis. Consider this equation: sodium chloride combines with water: NaCl + H2O → HCl + NaOH. The strong acid (HCl) and the strong base (NaOH) should cancel each other out, with no effect on pH. However, because the normal concentrations of Na+ and Cl − in the serum are 140 and 100, respectively, adding normal saline (154 mEq Na and 154 mEq Cl) causes the chloride to increase proportionately more than the sodium. This increase in chloride tips the acid–base balance toward HCl, thereby causing a metabolic acidosis.
57. D. Chronic pain is common in chronic kidney disease and most will rate their pain as moderate to severe. The absorption, metabolism, and renal clearance of opioids are complex in renal failure. However, with the appropriate selection and titration of opioids, patients with renal failure can achieve analgesia with minimal risk of adverse effects. Meperidine is not recommended in renal failure due to accumulation of normeperidine, which may cause seizures. Morphine is not recommended for chronic use in renal insufficiency due to the rapid accumulation of its active nondialyzable metabolite (morphine-6-glucuronide). Codeine has been reported to cause profound renal toxicity, which can be delayed and may occur after trivial doses. Dextropropoxyphene is associated with central nervous system and cardiac toxicity and is not recommended for use in patients with renal failure. On the other hand, fentanyl is considered relatively safe in renal failure, as it has no active metabolites.