Preventing postoperative

nausea and

42 l Nursing2013 l December

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By Mary H. Tinsley, ADN, RN, and Claudia P. Barone, RN, APN, CCNS-BC, CPC, LNC

FOR SURGICAL PATIENTS, postoperative nausea and vomiting (PONV) is one of the most undesired complications of anesthesia and surgery.1-3 PONV has been recognized as a surgical problem since 1848, shortly after the introduction of anesthesia.4 This article examines the underlying causes of PONV, potential complications, prevention and treatments, and nursing considerations before and after surgery. Potentially serious consequences Vomiting can lead to serious complications, including pulmonary aspiration, dehydration, and dysrhythmias secondary to electrolyte imbalances.4 About 10% of surgical patients develop PONV in the postanesthesia care unit (PACU), and up to 30% of surgical patients develop PONV within the first 24 hours.5 PONV also poses dangers for ambulatory surgery patients, who may go home before symptoms develop.6 The many variables that contribute to PONV, including type of surgery, anesthesia selection, opioid use, and preexisting conditions, make prevention and treatment a challenge.7 Treatment has improved with the advent of newer anesthetic and antiemetic drugs, but PONV remains difficult to understand and to treat.8,9

December l Nursing2013 l 43

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Defining the problem Nausea is a subjective and unpleasant sensation associated with the conscious awareness of the urge to vomit. Usually felt in the back of the throat and epigastrium, nausea is accompanied by the loss of gastric tone and contractions of the duodenum, with reflux of the intestinal contents into the stomach.2 Retching is rhythmic and spasmodic contractions of the respiratory muscles, chest wall, and abdominal muscles, without the expulsion of gastric contents. The glottis is closed. Gastric contents flow back and forth between the stomach and esophagus as the antral portion of the stomach contracts and the proximal portion

relaxes. Intra-abdominal pressure increases and intrathoracic pressure decreases.2 Vomiting, or emesis, is the forceful expulsion of gastric contents from the mouth. It’s brought about by coordinated motor changes involving muscles of the respiratory and gastrointestinal (GI) systems.10 Excessive distension or irritation of the duodenum provides an especially strong stimulus for vomiting. Impulses are transmitted by vagal and sympathetic afferents to the vomiting center of the medulla, prompting the automatic motor reactions that cause vomiting (see Physiologic events involved in vomiting). The motor impulses are transmitted from

Physiologic events involved in vomiting The vomiting center receives input from the gastrointestinal tract, higher cortical areas, vestibular apparatus, and chemoreceptor trigger zone. 9HVWLEXODU DSSDUDWXVLQSXW








Source: Porth CM. Essentials of Pathophysiology: Concepts of Altered Health States. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2011:698.

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the vomiting center through the 5th, 7th, 9th, and 12th cranial nerves to the upper GI tract and through the spinal nerves to the diaphragm and abdominal muscles.11 The hiatal portion of the diaphragm relaxes and intra-abdominal pressure is transferred to the thorax. The rectus abdominis and external oblique muscles of the anterior abdominal wall contract, the esophageal sphincter relaxes, reverse peristalsis occurs, and the glottis and mouth open as gastric contents are expelled.11 Emesis can be divided into three phases: • The preejection phase is characterized by the symptom of nausea and the autonomic signs of increased salivation, swallowing, pallor, diaphoresis, and tachycardia. • The ejection phase consists of retching and vomiting. • The postejection phase consists of relaxation of respiratory and abdominal muscles and cessation of nausea.6 The vomiting center can be stimulated by several sources. These include afferent neurons from the pharynx, GI tract, and mediastinum, as well as afferent neurons from the higher cortical centers (including the visual center and the vestibular portion of the eighth cranial nerve). Rapid position changes and motion in patients with vestibular disturbances can trigger vomiting and can be a profound problem in any PACU setting, but especially in the ambulatory care setting.10 Another cause of vomiting is the chemoreceptor trigger zone (CTZ) at the base of the fourth ventricle in the area postrema, a medullary structure in the brain. In the highly vascularized CTZ, vessels terminate in fenestrated capillaries surrounded by large perivascular spaces. Without an effective blood-brain barrier, the CTZ can be stimulated by chemicals in the blood (such as drugs) and cerebrospinal fluid.11,12

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The vomiting center can be activated indirectly when afferent pathways are stimulated by specific neurotransmitters—dopamine, serotonin, acetylcholine, and histamine—that activate the CTZ. Antiemetic drugs that block specific neurotransmitter receptors are used to prevent or treat PONV.4,13 The practice of making a patient N.P.O. overnight before surgery may lead to dehydration. In combination with anesthetic agents and surgical blood loss, dehydration can contribute to a state of transient ischemia in the GI system due to mesenteric hypoperfusion, one identified cause of PONV.13,14 Who’s at risk? Not all surgical patients experience PONV or experience it to the same degree. (See Rating an adult’s risk for PONV.) Understanding and identifying

Rating an adult’s risk for PONV1 Risk factor (each worth one point) • Female gender • History of PONV or motion sickness • Nonsmoker • Intraoperative or postoperative opioid therapy Prophylactic PONV therapy based on the patient’s score: 0 to 1 point—no intervention, or transdermal scopolamine patch preoperatively; or preoperative dexamethasone; or total I.V. anesthesia (TIVA); or prochlorperazine given I.V. or I.M. at the end of surgery. 2 points—one or two of the following: transdermal scopolamine patch preoperatively, I.V. dexamethasone preoperatively, TIVA, or prochlorperazine given I.V. or I.M. at the end of surgery. 3 or 4 points—three of the following: transdermal scopolamine patch preoperatively, I.V. dexamethasone preoperatively, TIVA, prochlorperazine given I.V. or I.M. at the end of surgery, or dolasetron I.V. at the end of surgery.

Nausea is a subjective and unpleasant sensation associated with the conscious awareness of the urge to vomit. risk factors can help clinicians decide whether the patient should receive prophylaxis or later treatment for PONV.5 Considerations include the patient’s condition and risk factors for PONV, the underlying disease process prompting the surgery, the type of surgery, and the anesthetic technique.15 • Patient age. Children under age 3 experience the lowest incidence of PONV; patients between ages 3 and 50 are most at risk.16,17 The risk of PONV typically decreases after age 50, although older patients undergoing spinal surgery or joint replacement are vulnerable to PONV due to length of anesthesia and reduced ability to clear these medications.11 • Gender. Among adults and adolescents, women are two to four times more likely to experience PONV than men, possibly due to varying levels of female hormones.15 No differences in PONV due to gender are found in preadolescents or patients age 80 or older.18 • Obesity. A positive correlation has been found between obesity and the

incidence of PONV. One likely reason is that adipose tissue acts as a reservoir for inhaled anesthetic agents, prolonging their half-lives so that the drugs continue to be released into the bloodstream during the recovery phase.5 Other possible reasons include a larger gastric volume, esophageal reflux, and airway difficulties that result in more gastric inflation.18 • History of PONV or motion sickness. Patients with a history of either motion sickness or PONV are believed to have a lower threshold of tolerance, which may increase their risk of future episodes of PONV by two to three times.3,11 A history of motion sickness or PONV is considered an independent predictor of PONV; the presumption is that the prior episodes established a reflex arc (an established pathway for nerve impulses) for vomiting.16 • Type of surgery. Surgeries that are associated with a higher incidence of PONV include breast augmentation or other plastic surgery, strabismus repair and other ophthalmic procedures, procedures associated with otolaryngology and gynecology (especially with a laparoscopic approach), orthopedic and abdominal surgery, and mastectomies and lumpectomies.5 Whether this is due to the type of surgical procedure, the length of the procedure, or the anesthetic agent used is unclear.11 • Length of surgery. PONV and length of surgery are strongly correlated.5 In a patient with a surgical procedure taking less than 30 minutes, the risk of PONV is 28%; for a procedure that lasts 151 to 180 minutes, the risk of PONV is 46.2%.11 Longer surgeries may result in the patient receiving potentially emetogenic anesthetic agents for a longer time, resulting in the increased percentage of patients with PONV.18 • Medications. Chloroform and ether, although no longer used for December l Nursing2013 l 45

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anesthesia, had the highest probability of causing PONV.10 Newer anesthetic agents such as propofol, and the use of patient-controlled analgesia, spinal opioid administration, and total I.V. anesthesia (TIVA), have reduced the incidence of PONV to about 30%, compared with 80% during the era in which ether was used.12 However, nitrous oxide and volatile anesthetic agents such as isoflurane and enflurane are all highly emetogenic, and general anesthesia causes more PONV than regional anesthesia. The use of opioids postoperatively about doubles the patient’s risk of PONV.16 • Tobacco use. Nonsmokers are at higher risk for developing PONV than smokers. The chemicals in cigarette smoke increase the metabolism of several drugs used in anesthesia, reducing the risk of PONV.16 Patients with one risk factor have a 10% to 21% chance of developing PONV. Those with two or more risk factors have an 80% chance of developing PONV.5 Preventive interventions Besides decreasing patient satisfaction and safety, PONV can lead

Women are two to four times more likely to experience PONV than men, possibly due to varying levels of female hormones. to poorer outcomes and extend patients’ length of stay, driving up healthcare costs. (See Complications associated with PONV.) Preventing PONV and providing early and effective management if it develops are critically important. These strategies help reduce the risk.

Complications associated with PONV25-27 Direct costs of PONV are associated with the cost of drugs, nursing time, and delays in PACU discharge. Indirect costs include hospital readmission for ambulatory surgery patients who develop PONV after returning home, delays in discharge, and loss of income for patients who can’t return to work as soon as they’d expected. Besides dehydration and electrolyte disturbances that can lead to cardiac dysrhythmias, complications of PONV include transient changes in intraocular pressure that can impair vision. (Report these changes to the anesthesia provider.) Pulmonary complications, often due to aspiration, are commonly seen in patients who wake up slowly from anesthesia or who can’t protect their airway. Position patients in Fowler or semi-Fowler position (unless contraindicated) to reduce the risk of aspiration. Position patients who can’t sit up on one side to prevent aspiration. PONV can also lead to wound dehiscence in surgical patients, and, rarely, esophageal rupture. Teach patients to splint their wounds when coughing, retching, or vomiting. Severe PONV can cause hematoma development, especially in patients undergoing thyroidectomy. Monitor the surgical site for edema and airway compression (difficult breathing). Administer prophylactic antiemetics as prescribed to help prevent retching and vomiting.

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• Regional anesthesia should be used instead of general anesthesia whenever possible. Fentanyl shouldn’t be used in combination with nitrous oxide in patients who have a history of PONV or motion sickness.6 • I.V. agents such as propofol should be used instead of inhaled volatile anesthetic agents when possible. • As appropriate, pain should be managed with nonsteroidal antiinflammatory drugs and regional blocks instead of opioids. If opioids are needed, the lowest effective dose should be used. Administer an antiemetic as prescribed and needed.6 • As prescribed, provide adequate presurgical hydration with crystalloids or colloids, which have been shown to reduce the incidence of PONV on the first postoperative day.5 • Providing 100% oxygen intraoperatively (via endotracheal tube or laryngeal mask airway) and 80% oxygen therapy for 30 minutes postoperatively may reduce the incidence of PONV by helping to clear anesthetic gases.5 Drugs for prevention and management Various drugs can be used to prevent PONV or manage it once it occurs (see Reviewing common antiemetic drugs). Rescue antiemetic therapy should be initiated as soon as the patient has been assessed for other factors contributing to PONV, such as opioid use, intestinal obstruction, or surgical complications. Patients who received a selective serotonin 5-HT3 receptor antagonist such as ondansetron as prophylaxis should be treated with a drug from another class.5 Although its mechanism of action isn’t clearly understood, dexamethasone, a corticosteroid, has been successfully used to manage PONV, and administering it during anesthesia induction may delay PONV.19 Few studies have focused on combination

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Reviewing common antiemetic drugs5,6 Common adverse reactions are italicized. Drug

Receptor site blocked

Adverse reactions

Dexamethasone (corticosteroid)

Prostaglandin activity in the cerebral cortex (theorized)

GI upset, anxiety, insomnia, hyperglycemia, facial flushing, euphoria, perineal itching or burning

Dolasetron, granisetron, ondansetron (selective serotonin 5-HT3 receptor antagonists)

Serotonin receptors in the CTZ

Headache, prolongation of the QT interval, cardiac dysrhythmia, constipation, asthenia, somnolence, diarrhea, fever, tremor or twitching, ataxia, lightheadedness, dizziness, nervousness, thirst, myalgia, warm or flushing sensation on I.V. administration, transient elevations in hepatic enzymes

Prochlorperazine, promethazine (phenothiazines)

Dopamine receptors in the central nervous system (CNS)

Sedation, lethargy, skin sensitization, cardiovascular effects, EPS, cholestatic jaundice, hyperprolactinemia, neuroleptic malignant syndrome (NMS), hematologic abnormalities

Scopolamine transdermal patch (anticholinergic)

Acetylcholine receptors activated by vestibular input to the CTZ

Dry mouth, drowsiness, impaired eye accommodation, blurred vision, disorientation, memory disturbances, dizziness, hallucinations

Diphenhydramine, dimenhydrinate, hydroxyzine (antihistamines)

Acetylcholine in the CNS

Sedation, dry mouth, constipation, confusion, blurred vision, urinary retention

Droperidol (butyrophenone)

Dopamine receptors in the CTZ

Sedation, hypotension, tachycardia, prolongation of the QT interval, cardiac dysrhythmia, EPS, dizziness, hypertension, chills, hallucinations

Metoclopramide (substituted benzamide)

Antagonizes dopamine; release of acetylcholine

Sedation, restlessness, agitation, diarrhea, central nervous system depression, EPS, hypotension, NMS, supraventricular tachycardia (with I.V. administration)

Aprepitant (substance P and NK1 receptor antagonist)

NK1 receptors in the medulla vomiting center

Fatigue, weakness, hiccups, nausea, constipation, hypotension, bradycardia, dizziness, dehydration

therapy for PONV, but the combination of dexamethasone and a selective serotonin 5-HT3 antagonist has been found more effective than the use of either agent alone.3 Selective serotonin 5-HT3 receptor antagonists such as ondansetron, granisetron, palonosetron, and dolasetron are approved to prevent PONV and to treat PONV in patients who didn’t receive prophylactic therapy.5 In randomized placebo studies with highrisk PONV patients, ondansetron was shown to be more effective in treating vomiting than in treating nausea.5 Studies indicate no significant difference between single-dose

treatments of dolasetron and ondansetron. Granisetron is an effective treatment for PONV in patients undergoing abdominal or vaginal hysterectomy.5 Selective serotonin 5-HT3 receptor antagonists may prolong the QT interval; because of postmarketing reports of torsades de pointes, these drugs should be avoided in patients with congenital long QT syndrome and in those taking other drugs that may prolong the QT interval. Phenothiazines such as promethazine and prochlorperazine are more effective than ondansetron for preventing postoperative nausea, but no difference has been found in

the treatment of vomiting.5 Phenothiazines may cause extrapyramidal symptoms (EPS) such as dystonia, tardive dyskinesia, and akathisia, which can be disturbing to the patient. (Symptoms typically resolve when the drug is discontinued.) Diphenhydramine can be administered with prochlorperazine to reduce the chance of akathisia, but this increases the risk of sedation.5 Anticholinergic agents such as scopolamine block muscarinic receptors in the vestibular system. Scopolamine is available as a transdermal patch that should be applied the night before surgery (onset of action is 2 to 4 hours) and remain December l Nursing2013 l 47

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in place for at least 24 hours postoperatively.5 Scopolamine is contraindicated in patients with angle-closure glaucoma.4 Antihistamines are the drugs of choice for preventing PONV in patients undergoing middle ear surgeries because of the high concentration of histamine and muscarinic cholinergic receptors within the vestibular system.5 Hydroxyzine and dimenhydrinate are two commonly used antihistamines. • Hydroxyzine is also an anxiolytic, has bronchodilatory effects and a long duration of action, and isn’t associated with circulatory or respiratory compromise. Hydroxyzine also may supplement the analgesic effects of opioids.19 • Dimenhydrinate was found to be as effective as ondansetron in preventing PONV in a randomized prospective trial of patients undergoing laparoscopic cholecystectomy.5 In a meta-analysis of 18 trials involving more than 3,000 patients, dimenhydrinate was as effective as serotonin 5-HT3 receptor antagonists and droperidol in preventing PONV.5 Droperidol, a centrally acting antidopaminergic agent, prevents PONV and treats opioid-induced nausea and vomiting. It’s as effective as ondansetron and promethazine with no significant differences related to adverse events.3,20-22 However, use of droperidol has significantly decreased since 2001, when the FDA issued a boxed warning about the drug’s potential for QT interval prolongation and potentially fatal cardiac dysrhythmias such as torsades de pointes.4,5 Metoclopramide is another drug that’s no longer used as routinely for PONV because of serious adverse reactions (a boxed warning states that the drug may cause tardive dyskinesia) and the availability of more effective treatments.5 Metoclopramide acts centrally in 48 l Nursing2013 l December

A history of motion sickness or PONV is considered an independent predictor of PONV. the CTZ and peripherally in the GI tract to increase lower esophageal sphincter tone and promote gastric motility. The drug is as effective as ondansetron for treating postoperative nausea but isn’t as effective for postoperative vomiting.5 Metoclopramide crosses the blood-brain barrier and causes centrally mediated adverse reactions, such as somnolence, reduced mental acuity, anxiety, depression, and EPS in young children and older adults. Aprepitant, the first substance P and neurokinin-1 receptor antagonist approved by the FDA for prevention of PONV, is an oral drug administered 3 hours before induction of general anesthesia. Aprepitant also is used to treat nausea and vomiting associated with chemotherapy.10 Other therapies Nonpharmacologic interventions can be effective in selected patients. The mechanisms of PONV are triggered by neurochemicals creating a strong mind-body link, and nondrug therapies work well in anxious

patients.4 Two such interventions include acupressure and aromatherapy.23 Acupressure wristbands have been shown to be effective when applied before anesthesia in patients undergoing short surgical procedures such as hysterectomy, tonsillectomy, or adenoidectomy. A meta-analysis of 19 studies on acupuncture, electroacupuncture, transcutaneous electrical nerve stimulation, acupoint stimulation, and acupressure found that these techniques were similar to pharmacologic agents in preventing early and late vomiting.5 Few studies have investigated the use of aromatherapy for PONV. A study of 33 surgical patients concluded that aromatherapy using isopropyl alcohol or essential oil of peppermint is effective in reducing nausea in surgical patients, but this may be due to controlled breathing patterns rather than the scents used in the trial.5 Commonly used aromatherapy scents include essential oil of ginger, essential oil of peppermint, and isopropyl alcohol.7 The scents are thought to affect the neurotransmitters that activate the CTZ.24 Lower the risks By identifying patients at risk for PONV and taking steps to prevent and manage it, nurses can help patients have the best outcomes. ■ REFERENCES 1. Kapoor R, Hola ET, Adamson RT, Mathis AS. Comparison of two instruments for assessing risk of postoperative nausea and vomiting. Am J Health Syst Pharm. 2008;65(5):448-453. 2. Becker DE. Nausea, vomiting, and hiccups: a review of mechanisms and treatment. Anesth Prog. 2010;57(4):150-156. 3. Chepyala P, Olden KW. Nausea and vomiting. Curr Treat Options Gastroenterol. 2008;11(2): 135-144. 4. McCaffrey R. Make PONV prevention a priority. OR Nurse. 2007;1(2):39-45. 5. Wilhelm SM, Dehoorne-Smith ML, Kale-Pradhan PB. Prevention of postoperative nausea and vomiting. Ann Pharmacother. 2007;41(1):68-78.

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6. Collins AS. Postoperative nausea and vomiting in adults: implications for critical care. Crit Care Nurse. 2011;31(6):36-45. 7. Conway B. Prevention and management of postoperative nausea and vomiting in adults. AORN J. 2009;90(3):391-413. 8. Nunley C, Wakim J, Guinn C. The effects of stimulation of acupressure point P6 on postoperative nausea and vomiting: a review of literature. J Perianesth Nurs. 2008;23(4):247-261. 9. Kloth DD. New pharmacologic findings for the treatment of PONV and PDNV. Am J Health Syst Pharm. 2009;66(1 suppl 1):S11-S18. 10. Diemunsch P, Joshi GP, Brichant JF. Neurokinin-1 receptor antagonists in the prevention of postoperative nausea and vomiting. Br J Anaesth. 2009;103(1):7-13. 11. Sikka R, Kaul TK, Grewal A, Satija A. Postoperative nausea and vomiting. J Anesth Clin Pharm. 2007;23(4): 341-356. 12. Kovac AL. Management of postoperative nausea and vomiting in children. Paediatr Drugs. 2007;9(1):47-69. 13. McCracken G, Houston P, Lefebvre G; Society of Obstetricians and Gynecologists of Canada. Guideline for the management of postoperative nausea and vomiting. J Obstet Gynaecol Can. 2008; 30(7):600-607, 608-616. 14. Chaudhary S, Sethi AK, Motiani P, Adatia C. Pre-operative intravenous fluid therapy with crystalloids or colloids on post-operative nausea & vomiting. Indian J Med Res. 2008;127(6):577-581.


15. Mathias JM. Protect your patients from nausea, vomiting. OR Manager. 2008;24(4):27-28.

nausea and vomiting. Cochrane Database Syst Rev. 2012;4:CD007598.

16. Miaskowski C. A review of the incidence, causes, consequences, and management of gastrointestinal effects associated with postoperative opioid administration. J Perianesth Nurs. 2009;24(4): 222-228.

24. Winston AW, Rinehart RS, Riley GP, Vacchiano CA, Pellegrini JE. Comparison of inhaled isopropyl alcohol and intravenous ondansetron for treatment of postoperative nausea. AANA J. 2003;71(2):127-132.

17. Gan TJ, Meyer TA, Apfel CC, et al. Society for ambulatory anesthesia guidelines for the management of postoperative nausea and vomiting. Anesth Analg. 2007;105(6):1615-1628. 18. Odom-Forren J. Measurement of postdischarge nausea and vomiting for ambulatory surgery patients: a critical review and analysis. J Perianesth Nurs. 2011; 26(6):372-383. 19. Pfizer Labs. Vistaril (hydroxyzine pamoate) capsules and oral suspension. files/products/uspi_vistaril.pdf. 20. Apfel CC, Cakmakkaya OS, Frings G, et al. Droperidol has comparable clinical efficacy against both nausea and vomiting. Br J Anaesth. 2009;103(3):359-363. 21. Ignoffo RJ. Current research on PONV/PDNV: practical implications for today’s pharmacist. Am J Health Syst Pharm. 2009;66(1 suppl 1):S19-S24. 22. Kreisler NS, Spiekermann BF, Ascari CM, et al. Small-dose droperidol effectively reduces nausea in a general surgical adult patient population. Anesth Analg. 2000;91(5):1256-1261. 23. Hines S, Steels E, Chang A, Gibbons K. Aromatherapy for treatment of postoperative

25. Rother C. Postoperative nausea and vomiting: use of antiemetic agents in anaesthesia. Scottish Universities Med J. 2012;1(11):89-97. 26. Bononi M, Amore Bonapasta S, Vari A, et al. Incidence and circumstances of cervical hematoma complicating thyroidectomy and its relationship to postoperative vomiting. Head Neck. 2010;32(9): 1173-1177. 27. Kranke P, Schuster F, Eberhart LH. Recent advances, trends and economic considerations in the risk assessment, prevention and treatment of postoperative nausea and vomiting. Expert Opin Pharmacother. 2007;8(18):3217-3235. Mary H. Tinsley is an RN III in the PACU at the University of Arkansas Medical Center in Little Rock, Ark. Claudia P. Barone is a professor at the University of Arkansas for Medical Sciences’ College of Nursing, an advanced practice partner in the department of nursing, and an RN II in the department of nursing’s PRN pool. This article first appeared in OR Nurse. 2012;6(3):18-25. The authors and planners have disclosed that they have no financial relationships related to this article. DOI-10.1097/01.NURSE.0000428698.64345.c8

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Preventing postoperative nausea and vomiting.

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