Factors Affecting Postoperative Nausea and Vomiting in Surgical Patients

ORIGINAL ARTICLE

Factors Affecting Postoperative Nausea and Vomiting in Surgical Patients Jaesoon Son, MS, RN, Haesang Yoon, PhD, RN Purpose: This study was to identify factors affecting postoperative nausea and vomiting (PONV) and to investigate the incidence of PONV for the first 24 hours after operation. Design: The prospective research was performed in an 1,100-bed university hospital, from April to December, 2011. The sample consisted of 609 patients with elective surgery. Methods: Factors affecting PONV were identified by multiple logistic regression. Findings: Incidence of PONV was 27.1% for the first postoperative 24 hours. Insertion of nasogastric tube (OR, 4.54, P 5 .002), history of PONV (OR, 3.24, P , .001), general anesthesia (OR, 2.76, P 5 .002), history of motion sickness (OR, 2.33, P , .001), and female sex (OR, 2.05, P 5 .004) were high risk factors of PONV. The nonadministration of antiemetics during operation (OR, 1.70, P 5 .014) and nonuse of intravenous patient-controlled analgesia (OR, 1.54, P 5 .038) increased PONV during the first postoperative 24 hours. Conclusions: Patients of female gender, history of motion sickness and PONV, general anesthesia, and nasogastric insertion are more likely to experience PONV.

Keywords: postoperative nausea and vomiting (PONV), postoperative care, risk factor. Ó 2016 by American Society of PeriAnesthesia Nurses

POSTOPERATIVE NAUSEA AND VOMITING (PONV) is a common perioperative complication of surgery under anesthesia, which occurs within the first 24 hours postoperatively.1 PONV is a secondary discomfort related to surgical procedures followed by postoperative pain.2 PONV can lead to postoperative complications that include fluid and electrolyte imbalances, suture tension, esophageal tear, abdominal wound dehiscence, and increased intracranial pressure.3 The incidence of PONV ranges from 25% to 30% during the first

postoperative 24 hours4-6 and PONV lasts more than 3 days after surgery.7

Jaesoon Son, MS, RN, is a Nurse Anesthetist, Lactation Consultant Clinic, Changwon, Kyungsangnamdo, Republic of Korea. Haesang Yoon, PhD, RN, is a Professor, College of Nursing, Gachon University, Korea, and she is Dean of College of Nursing and Graduate School of Nursing. Conflict of interest: None to report.

Address correspondence to Haesang Yoon, College of Nursing, Gachon University, Younsoodong 534-2, Younsoogu, Incheon 406-812, Korea; e-mail address: yoonhs@ gachon.ac.kr. Ó 2016 by American Society of PeriAnesthesia Nurses 1089-9472/$36.00 http://dx.doi.org/10.1016/j.jopan.2016.02.012

Journal of PeriAnesthesia Nursing, Vol -, No - (-), 2016: pp 1-10

1

The risk factors of PONV include female gender, age less than 50 years, pregnancy, history of motion sickness or PONV, body mass index less than 25 kg/m2, nonsmoking status, surgery related to laparoscopic procedures, duration of surgery $ 1 hour,8-11 and type of surgery.12-14 PONV seems related to general anesthesia, use of intravenous patient-controlled analgesia (IV-PCA), and inhalation anesthetics

SON AND YOON

2

including enflurane or nitrous oxide, administration of cholinergics, or opioids.13,15-17 The administration of intraoperative or postoperative opioids is associated with a two-fold to four-fold increased incidence of PONV.10 Providing multimodal analgesia that minimizes the use of opioids is helpful to decrease the risks for PONV. The incidence of PONV seems to increase exponentially as the number of risk factors of PONV increases.18 Therefore, individual risk factors for PONV should be considered primarily in nursing care of surgical patients under general or spinal anesthesia. Although risk factors of PONV for Koreans have been identified, some points of view need to be considered. First, current risk factors of PONV for Koreans are needed because those studies were performed over 10 years ago.5,6 Second, although enflurane and isoflurane have been replaced with desflurane or sevoflurane, fewer studies have examined PONV in surgical patients with desflurane or sevoflurane. Third, there is discrepancy of PONV risk factors such as age, smoking, or duration of surgery.13,18 This prospective, observational study investigated factors affecting PONV during the first 24 hours after surgery and incidence of PONV for the first 48 hours postoperatively.

Methods Research Subjects Subjects who had been scheduled for elective surgery under anesthesia were recruited from September 2010 to May 2011 at Eulgi University Hospital, an 1,100-bed general hospital in Daejeon, Korea. Inclusion criteria were adults more than 18 years, conscious state, class I or II in American Society of Anesthesiologist Physical Status Classification System denoting a healthy person or those with mild systemic disease, and surgical patients under general or spinal anesthesia. All patients had to be communicative and scheduled for either gastrointestinal, orthopaedic, or gynecological surgery. Pregnant patients were excluded before actual recruitment, and the patients who received preoperative antiemetics (n 5 4) or enflurane for inhalation anesthetics (n 5 14) were withdrawn from the study later (Figure 1). In addition, the surgical patients (n 5 3) who were transferred to the intensive care unit postoperatively, or had duration of surgery less than 1 hour were excluded from the study.

Setting and Samples This study was approved by the Ethics and Research Committee of Eulgi University Hospital (IRB No: 10-08). Patients were recruited by a nurse anesthetist as a convenience sample from the surgery wards at the preanesthesia visit after admission. The patients were fully informed about the purpose, design, duration of this study, and ability to withdraw from the study at any time. After participation was accepted, each subject signed a study consent form, and the written consent form was obtained from each participant. Based on the previously reported PONV incidence and odds ratio (OR),12,15,18 the incidence of PONV was determined as 36% for this study and the OR of PONV as 1.82. Given these values, an alpha of 0.05, and a power of 0.95, a total of 600 subjects were needed through G-power 3.1 for multiple logistic regression analysis. Considering a 5% dropout rate, we recruited 630 participants. Anesthetic Technique General and spinal anesthesia were performed with a standardized technique. General anesthesia was induced by an intravenous administration of 1.5 mg/kg propofol, 1 mg/kg rocuronium, and 10 mcg alfentanil, and an endotracheal tube was inserted in the trachea. According to patient’s condition and anesthesiologist’s preference, inhalation anesthesia was maintained with one of the three inhalation anesthetics (1.5% to 2% isoflurane, 5% to 7% desflurane, and 1.5% to 3% sevoflurane). At the commencement of skin suture, the neuromuscular blockade was reversed with neostigmine (1.0 mg) and atropine (1.0 mg). In spinal anesthesia, lumbar puncture was performed through an interspace (L3-4 or L4-5). A 23-gauge Quincke needle was inserted using a midline approach at L3-4 or L4-5. All patients were hydrated with 8 mL/kg body weight Ringer’s lactate solution before anesthesia. IV-PCA was provided for patients who wanted a PCA at the completion of skin suture in the operating room. The IV-PCA regimen typically consisted of morphine (15 mcg/kg/mL), ketorolac (25 mcg/kg/mL), and ondansetron 4 mg plus normal saline (total volume of 100 mL), and was administered through a pump, programmed to deliver 2 mL/hour as a background infusion and

POSTOPERATIVE NAUSEA AND VOMITING

3

&RQYHQLHQFH VDPSOHRI HOLJLEOHSDWLHQWVZLWKVXUJLFDOSDWLHQWV JDVWURLQWHVWLQDORUWKRSHGLF RUJ\QHFRORJLFDOVXUJHU\

 SDWLHQWV H[FOXGHGGXHWR SUHPHGLFDWLRQZLWK DQWLHPHWLFV Q



SRVWRSHUDWLYHWUDQVIHUWRLQWHQVLYHFDUHXQLWQ DGPLQLVWUDWLRQRIHQIOXUDQH Q





 SDWLHQWVDQDO\]HG

Figure 1. Flow diagram of study participants for factors affecting PONV.

0.5 mL per demand, with a 15-minute lockout during a 48-hour period. Data Collection During the preanesthesia interview, gender, age, American Anesthesiologists’ Association physical status classification, disease, smoking history, and previous history of motion sickness or PONV were collected by a nurse anesthetist. Weight and height (DS-103, Dong Sahn Jenix, Seoul, Korea) were measured at admission to the surgical unit by a unit nurse. Body mass index (kg m22) was calculated using the Kauffman Index. All the patients for general anesthesia were premedicated with atropine (1.0 mg) and midazolam (2 mg) or lorazepam (1 mg) intramuscularly 30 minutes before the transfer to surgery. Vital signs,

PONV and pain were monitored at 30 minutes, 1 hour, 2 hours, 4 hours, 24 hours, and 48 hours postoperatively by nurses who were working in the postanesthesia care unit (PACU) or surgical units. The investigator gave specific instructions to the nurses on the surgery units. These nurses collected vital signs, PONV and pain assessments at 24 hours and 48 hours postoperatively. PONV or pain was measured on a numerical rating scale (NRS; 0 5 no nausea to 10 5 worst possible nausea; 0 5 no pain to 10 5 worst possible pain). Index of nausea, vomiting, and retching (INVR) was measured at 24 hours and 48 hours postoperatively using an INVR scale,19 a self-report instrument consisting of eight items using a five-point scale (0 5 no to 5 5 very severe). A patient was considered to have had PONV if any nausea and/ or emetic episodes occurred and rescue

SON AND YOON

4

 3219156 3219,195

3219 156 ,195 6FRUH



—

 —



Q  

—­SQ

Q   — 

—†Q

Q  

Q  

—ˌSQ

—­SQ 

—­SQ

Q  

Q   3RVWRSHUDWLYH7LPH

 $UULYDODW3$&8

PLQ

KU

KU

KU

KU

Figure 2. Incidence and level of postoperative nausea and vomiting (N 5 609). x, comparison between time at PACU and each time for NRS; *P , .001; z, comparison between time postoperative 24 and 48 hours for INVR; %, incidence of PONV at each time. PACU, postanesthesia care unit; PONV, postoperative nausea and vomiting; NRS, numeric rating scale; INVR, index of nausea, vomiting, and retching. This figure is available in color online at www.jopan.org.

antiemetics were administered postoperatively at least once during the research periods.15,19 In an earlier study,20 the Cronbach a for INVR was 0.912 to 0.968; the Cronbach a in this study was 0.911 (Figure 2). Additional data included duration of anesthesia and surgery, type of anesthesia and surgery, inhalation agent, use of IV-PCA, insertion of nasogastric tube, and administration of antiemetics after surgery. A polyethylene Levin tube 16 to 18 Fr for the nasogastric tube was inserted through the nose down into the stomach by institutional guidelines. IV-PCA and PONV management were also conducted in regular sequence by institutional guidelines. Patients were given rescue antiemetic including ondansetron (Zofran), or metoclopramide (Macperan) if they complained of moderate to severe nausea (NRS PONV $ 4), had symptoms (vomiting, retching) and/or on the request. Administrations of all rescue antiemetics were recorded. Data Analyses Data were analyzed using IBM SPSS 19.0 (Armonk, NY). The chi-square test and t test were used to identify differences of the demographic and

physiological characteristics between the absence of PONV (INVR 5 0) and the presence of PONV (INVR $ 1) groups. There were some significant differences in nine variables between the two groups; age, gender, history of motion sickness and of PONV, duration of surgery and of anesthesia, type of anesthesia, administration of antiemetics during operation, and use of IV-PCA (Tables 1 and 2). Therefore, the nine variables for binary explanatory variables were used in the multiple logistic regression. To identify independent predictors for PONV, the multiple logistic regression was used through a forward selection procedure (P , .05 to enter). In this model, the estimated probability of PONV, denoted by P, depends on the score Z according to the formula P 5 1/1 1 eZ, in which, Z 5 b0 1 b1 1 b2..1 bk is weighted sum of the values of risk factor, coded as 1 if present and 0 if absent, with b1, b2.. bk as the weight or estimated regression coefficient, and each described as OR associated with the corresponding factor. The corresponding OR was obtained from ORj 5 exp (bj) for factor(j). The intercept b0 means the baseline log OR of PONV, that is, P0 5 1/1 1 eZ-b0 is the estimated baseline risk of PONV in patients without any risk factors.

POSTOPERATIVE NAUSEA AND VOMITING

5

Table 1. General Characteristics of Subjects (N 5 609) PONV for Postoperative 24 h Mean ± SD or n (%) Characteristics Age, y 50, 50$ Gender Female Male Smoking Yes No History of motion sickness Yes No History of hyperemesis gravidarum Yes No History of surgery Yes No History of PONV Yes No Body mass index Pain by NRS At postoperative 4 h At postoperative 24 h

No (INVR 5 0; n 5 444)

Yes (INVR $ 1; n 5 165)

x2, t, or Z*

48.9 6 16.4 234 (52.7) 210 (47.3)

46.8 6 16.2 103 (62.4) 62 (37.6)

21.44 4.60

.149 .032

286 (64.4) 158 (35.6)

129 (78.2) 36 (21.8)

10.50

.001

63 (14.2) 381 (85.8)

17 (10.3) 148 (89.7)

1.59

.207

76 (17.1) 368 (82.9)

87 (52.7) 78 (47.3)

39 (14.6) 228 (85.4)

15 (10.1) 133 (89.9)

1.68

.195

227 (51.1) 217 (48.9)

91 (55.2) 74 (44.8)

0.78

.377

31 (7.0) 413 (93.0) 24.1 6 3.5

37 (22.4) 128 (77.6) 24.3 6 3.7

28.9 1.24

.451

3.87 6 1.95 2.72 6 1.73

4.05 6 1.75 2.59 6 1.56

20.56* 20.69*

.573 .488

18.7

P

, .001

, .001

INVR, index of nausea, vomiting, and retching; NRS, numeric rating scale; PACU, postanesthesia care unit; PONV, postoperative nausea and vomiting. *Mann-Whitney U test.

Results Of the 630 participants, 609 patients (96.7%) completed the study. Twenty-one participants were withdrawn from the study because of premedication of antiemetics (n 5 4), transfer to the intensive care unit postoperatively (n 5 3), and use of enflurane (n 5 14) (Figure 1). The 609 patients were divided into the absence of PONV (INVR 5 0, n 5 444) or the presence of PONV (INVR . 1, n 5 165) groups. Overall, 165 patients (27%) experienced PONV (INVR $ 1) at least once during 24 hours after completion of surgery. Results of the Student t test, Mann-Whitney U test or chi-square test for the demographic and physiological characteristics between the two groups are presented in Tables 1 and 2.

Distribution of gender (P 5 .002), age (P 5 .032), history of motion sickness (P , .001) and PONV (P , .001), insertion of nasogastric tube (P 5 .008), type of surgery (P 5 .001), type of anesthesia (P , .001), administration of antiemetics during operation (P 5 .049), and use of IV-PCA (P 5 .025) were significantly different between the two groups. There were significant differences for duration of operation (P 5 .001) and anesthesia (P 5 .014) between the two groups (Tables 1 and 2). There were no differences observed in pain at 4 hours and 24 hours postoperatively.

Incidence and Level of PONV Overall, 165 patients (27%) experienced PONV during the first postoperative 24 hours and 36

SON AND YOON

6

Table 2. Comparison of Subject Characteristics According to PONV (N 5 609) PONV for Postoperative 24 h No (INVR 5 0; n 5 444) Characteristics Type of surgery Gastrointestinal Orthopaedic OB & GY Duration of surgery, min , 60 $60 Duration of anesthesia, min , 100 $100 Laparoscopic surgery Yes No Insertion of nasogastric tube Yes No Type of anesthesia General Spinal Inhalation agent for general anesthesia (n 5 487) Isoflurane Sevoflurane Desflurane Administration of antiemetics during operation Yes No Use of IV-PCA Yes No Administration of antiemetics after surgery* Zofran 4 mg Zofran 8 mg Macperan Total

Yes (INVR $ 1; n 5 165) x2 or z

Mean ± SD or n (%) 145 (32.7) 165 (37.2) 134 (30.2) 94.5 6 62.7 158 (35.6) 286 (64.4) 143.2 6 90.9 157 (35.4) 287 (64.6)

79 (47.9) 39 (23.6) 47 (28.5) 115.6 6 76.3 48 (29.1) 117 (70.9) 163.5 6 86.9 51 (30.9) 114 (69.1)

127 (28.6) 317 (71.4)

P

14.3

.001

3.07 2.27

.001 .132

2.47 1.06

.014 .303

52 (31.5) 113 (68.5)

0.49

.483

10 (2.3) 434 (97.7)

11 (6.7) 154 (93.3)

7.04

.008

338 (76.1) 106 (23.9)

149 (90.3) 16 (9.7)

82 (24.3) 16 (4.7) 240 (71.0)

43 (28.7) 5 (3.3) 102 (68.0)

1.34

.498

170 (38.3) 274 (61.7)

49 (29.7) 116 (70.3)

3.89

.049

239 (53.8) 205 (46.2)

72 (43.6) 93 (56.4)

5.01

.025

2 (50.0) 2 (25.0) 0 4 (100.0)

93 (51.7) 81 (45.0) 6 (3.3) 180 (100.0)

15.3

-

, .001

-

INVR, index of nausea, vomiting, and retching; IV-PCA, intravenous patient controlled analgesia; Macperan, Metoclopramide 5 mg; OB & GY, obstetrical and gynecological; PONV, postoperative nausea and vomiting; Zofran, Ondansetron. *Multiple response.

patients (5.9%) during the next postoperative 24 hours. The level of PONV (NRS 5.54) on arrival at PACU was higher than at postoperative 30 minutes in the PACU (NRS 4.92; P , .001), postoperative 1 hour (NRS 4.39; P , .001), postoperative 4 hours (NRS 3.24;

P , .001), postoperative 24 hours (NRS 3.11; P , .001), and postoperative 48 hours (NRS 2.51; P , .001) (Figure 2). INVR score at postoperative 24 hours (9.74) was higher than at postoperative 48 hours in the surgical units (3.09) (P , .001).

POSTOPERATIVE NAUSEA AND VOMITING

7

Table 3. Odds Ratios for Affecting Factors on PONV During Postoperative 24 h (N 5 609) Variables (Reference) Insertion of Levin tube (No) History of PONV (No) Type of anesthesia (Spinal) History of motion sickness (No) Gender (Male) Administration of intraoperative antiemetics (Yes) Use of IV-PCA (Yes) Age (50 $) Type of surgery (Orthopaedic)

Categories

b

SE

Wald

P

Odds Ratio

95% CI

Yes Yes General Yes Female No

1.51 1.18 1.02 0.85 0.69 0.53

.497 .290 .324 .231 .245 .215

9.24 16.4 9.82 13.5 6.54 6.05

.002 , .001 .002 , .001 .004 .014

4.54 3.24 2.76 2.33 2.05 1.70

1.71 to 12.0 1.83 to 5.72 1.46 to 5.23 1.48 to 3.67 1.16 to 3.03 1.11 to 2.58

No , 50 Gastrointestinal OB & GY

0.43 0.41 0.14

.208 .221 .149

4.29 3.43 0.83

.038 .064 .363

1.54 1.51 1.15

1.02 to 2.32 0.98 to 2.33 0.86 to 1.54

23.18

.654

, .001

0.04

Constant

23.7

CI, confidence interval; IV-PCA, intravenous patient controlled analgesics; OB & GY, obstetrical and gynecological; PONV, postoperative nausea and vomiting; SE, standard error.

Multiple Logistic Regression Analysis Table 3 displays the results of the multiple logistic regression analysis. Insertion of nasogastric tube (OR 5 4.54, P 5 .002), history of PONV (OR 5 3.24, P , .001), general anesthesia (OR 5 2.76, P 5 .002), history of motion sickness (OR 5 2.33, P , .001), and female gender (OR 5 2.05, P 5 .004) were factors affecting PONV. Nonadministration of antiemetics (OR 5 1.70, P 5 .014) during operation and nonuse of IV-PCA (OR 5 1.54, P 5 .038) increased the risks of PONV during the first postoperative 24 hours. The model of logistic regression fit because P value of the Hosmer and Lemeshow test was .616. Based on the above results, a predictive model was developed to calculate the probability of PONV: P (probability of PONV) 5 1/1 1 e2Z, where Z 5 23.18 1 1.51 (insertion of Levin tube) 1 1.18 (history of PONV) 1 1.02 (type of anesthesia) 1 0.85 (history of motion sickness) 1 0.69 (gender) 1 0.53 (administration of antiemetics) 1 0.43 (use of IV-PCA); (insertion of Levin tube: yes 5 1, no 5 0; history of PONV: yes 5 1, no 5 0; type of anesthesia: general 5 1, spinal 5 0; history of motion sickness: yes 5 1, no 5 0; gender: female 5 1, male 5 0; administration of antiemetics: no 5 1, yes 5 0; use of PCA: no 5 1, yes 5 0) (Table 3). However, multiple logistic regression results demonstrated that age, history of hyperemesis,

smoking, duration of surgery and anesthesia, inhalation anesthetics, laparoscopic surgery, and type of surgery did not affect PONV.

Discussion The study revealed the risk factors related to PONV as female gender, history of motion sickness and PONV, general anesthesia, and insertion of nasogastric tube. Insertion of nasogastric tube was the most influential risk factor of PONV, explaining that mechanical irritations by instrumentation led to PONV increasing stimulation pharyngeal or vagal nerve.21 A history of PONV and motion sickness were the second and fourth influential risk factors for PONV, respectively, and those findings agree with previous findings.4,11,12,18 However, history of hyperemesis showed no influence on PONV. As motion sickness is associated with sensitivity to the vomiting center or the chemoreceptor trigger zone1 and hyperemesis is associated with estrogen at pregnancy, it is natural that history of hyperemesis has no influence on PONV. Inhalation agents stimulate the vomiting center and the chemoreceptor trigger zone.1 In the present study, general anesthesia was also a risk factor of PONV compared with spinal anesthesia, which is in accordance with previous studies.16,18 However, the type of inhalation anesthetics and duration of surgery and anesthesia did not affect PONV, whereas some previous findings reported that duration of surgery $ 1 hour was a risk

8

SON AND YOON

factor of PONV.7,12 This disagreement about duration of surgery seems to be attributable to different research protocol such as administration of antiemetics or measurement time of PONV.7,12 Patients with ambulatory surgery can be at risk for PONV because of physical movements on their way to home after discharge from the hospital and limited treatment for PONV after discharge.1,7,22

of Choi et al12 seemed not to include antiemetics. Presently, the intraoperative administration of antiemetics decreased the risk of PONV, which supported the findings of other investigators.7,13,18 These collective findings imply that administration of antiemetics is the significant protective factor for PONV. Therefore, we suggest administration of antiemetics to surgical patients with risk factors of PONV to prevent PONV.

Although some previous studies reported that smoking had affected PONV,10,12,23,24 our findings showed smoking did not affect PONV, which was supported by Apfel et al.18 Those discrepancies can be attributed to different times of PONV measurement. Other investigators10,12,23 measured PONV in the PACU, at postoperatively at 2 hours, whereas we measured PONV during 24 hours postoperatively. Polycyclic aromatic hydrocarbons in tobacco smoke induce production of cytochrome P450, which engages in quick metabolism of inhalation anesthetics and decreases PONV by inhalation anesthetics.25-27 As 5% of inhalation anesthetics remain for 2 hours after completion of anesthesia,28 cytochrome P450 seems to affect the decrease of PONV for 2 hours after completion of anesthesia. Although cytochrome P450 seems to be irrelevant to PONV at least after 24 hours postoperatively, further study is needed.

Although young age is a risk factor of PONV,1,9 age did not affect PONV in our study, which is supported by some findings.11,15 This discrepancy can be attributed to the range of age. As differences of age were just 2.1 years between the two groups with PONV or without, difference in 2.1 years was too small to affect PONV. In addition, our findings show that surgical type such as gastrointestinal, orthopaedic or obstetrical, and gynecological surgery did not affect PONV, which supports the findings of Apfel et al.9 However, other investigators reported that gastrointestinal or orthopaedic surgery was a risk factor of PONV.13,14 This disagreement may come from different independent variables included in multiple logistic regression. For example, Dienemann et al13 did not include independent variables such as insertion of nasogastric tube, use of IV-PCA or administration of antiemetics, which we included in our multiple logistic regression.

Presently, the duration of anesthesia did not affect PONV. Our findings did not support the data of some previous investigators.7,12,15 However, it is notable that uptake of inhalation anesthetics increases by 20% when duration of anesthesia rises 1 hour from 2 to 3 hours.28 In the present study, the 20-minute difference in the duration of anesthesia between the groups with/without PONV seemed too small to exert any influence on PONV. As some previous studies did not report the duration of anesthesia,7,12,15 further research is needed to make clear that the duration of anesthesia has influences on PONV.

The incidence of PONV was 27.1% and 5.9% during the first postoperative 24 hours and the next postoperative 24 hours, respectively. Our findings for the first postoperative 24 hours are similar to the rate of 27.4% and 26.2% by the previous researchers,12,13 but were far lower than the 37% by Apfel et al18 and 44.8% by OdomForren et al.7 Research subjects in the studies of Choi et al12 and Dienemann et al13 stayed in the PACU or surgical unit for more than 48 hours postoperatively, whereas subjects in the studies of Apfel et al18 and Odom-Forren et al7 stayed during postoperative 6 hours after ambulatory surgery and were discharged. The patients with ambulatory surgery left the hospitals 6 hours after surgery. Lack of supplemental oxygen and movement before sufficient recovery from anesthesia and surgery can trigger PONV because of hypotension and dizziness, and PONV after discharge can interrupt the swift approach to PONV treatment.1,22

Although Choi et al12 reported that IV-PCA–based opioids were a risk factor of PONV, our findings showed that the use of IV-PCA decreased PONV. This variance may be because the IV-PCA regimen can vary by each hospital or anesthesiologist. The IV-PCA regimen in our study added antiemetics such as ondansetron, whereas the IV-PCA regimen

POSTOPERATIVE NAUSEA AND VOMITING

9

We identified factors affecting PONV and developed a Korean predictive model for PONV. This model can be used to calculate the probability of PONV to administer prophylactic antiemetics in high-risk PONV patients. The present risk model is: Z 5 23.18 1 1.51 (insertion of nasogastric tube) 1 1.18 (history of PONV) 1 1.02 (general anesthesia) 1 0.85 (history of motion sickness) 1 0.72 (female) 1 0.53 (nonadministration of antiemetics) 1 0.43 (nonuse of IVPCA). However, age, history of hyperemesis, laparoscopic surgery, and type of surgery seem not to affect PONV.

patients to take an active involvement in symptom management. There are some limitations in the present study. First, we did not control dosage and type of opioids and antiemetics. However, the patients received a standardized morphine-based PCA regimen. Second, we did not control physical movement, oxygen, and fluid therapy for 48 hours. Third, this study did not control size of Levin tube over PONV, or include surgical patients with maxillofacial or thyroid operations, which can affect PONV.12

Conclusion We suggest further research for testing of this predictive model for PONV with seven risk factors. In clinical practice, it is recommended to screen for PONV risk factors in the preoperative assessment for further evaluation and treatment after the surgery. Organizational efforts are needed to ensure relevant education around PONV and to prepare evidence-based perioperative protocols with consideration of preoperative assessment for PONV risk factors. Health care providers are needed to make a plan for individual care of PONV for surgical patients and assist surgical

Insertion of nasogastric tube, history of PONV, general anesthesia, history of motion sickness, and female gender seem to be more important influences affecting PONV for the first postoperative 24 hours. Therefore, perioperative care providers need to screen PONV risk factors such as insertion of nasogastric tube, history of PONV, general anesthesia, history of motion sickness, and female gender in the preoperative assessment to reduce PONV and to prevent associated postoperative complications or adverse outcomes related to PONV.

References 1. American Society of PeriAnesthesia Nurses (ASPAN) PONV/PDNV Strategic Work Team. ASPAN’s evidencebased clinical practice guideline for the prevention and/or management of PONV/PDNV. J Perianesth Nurs. 2006;21: 230-250. 2. Oh SH, Kim IH, Choi SR, Chung CJ. Causes of patient dissatisfaction with anesthetic care. Korean J Anesthesiol. 2005;48:387-392. 3. Neufeld SM, Newburn-Cook CV. What are the risk factors for nausea and vomiting after neurosurgery? A systematic review. Can J Neurosci Nurs. 2008;30:23-34. 4. Moreno C, Veiga D, Pereira H, Martinho C, Abelha F. Postoperative nausea and vomiting: Incidence, characteristics and risk factors - A prospective cohort study. Rev Esp Anestesiol Reanim. 2013;60:249-256. 5. Kim MK, Bai SJ, Han JM, Lee YK, Kim JS, Shin YS. The incidence of nausea and vomiting in immediate postanesthetic period. Korean J Anesthesiol. 2004;47:472-476. 6. Kim EJ, Ahn HJ, Park SH, Bang SR, Choi DH. Risk factors of postoperative nausea and vomiting: Development of Korean risk model. Korean J Anesthesiol. 2005;48:380-386. 7. Odom-Forren J, Jalota L, Moser DK, et al. Incidence and predictors of postdischarge nausea and vomiting in a 7-day population. J Clin Anesth. 2013;25:551-559. 8. Cronin SN, Odom-Forren J, Roberts H, Thomas M, Williams S, Wright MI. Effects of controlled breathing, with or

without aromatherapy, in the treatment of postoperative nausea. J Perianesth Nurs. 2015;30:389-397. 9. Apfel CC, Heidrich FM, Jukar-Rao S, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012;109:742-753. 10. Apfel CC, L€a€ar€a E, Koivuranta M, Greim CA, Roewer N. A simplified risk score for predicting postoperative nausea and vomiting: Conclusions from cross-validations between two centers. Anesthesiology. 1999;91:693-700. 11. Murphy MJ, Hooper VD, Sullivan E, Clifford T, Apfel CC. Identification of risk factors for postoperative nausea and vomiting in the perianesthesia adult patient. J Perianesth Nurs. 2006;21:377-384. 12. Choi DH, Ko JS, Ahn HJ, Kim JA. A Korean predictive model postoperative nausea and vomiting. J Korean Med Sci. 2005;20:811-815. 13. Dienemann J, Hudgens AN, Martin D, et al. Risk factors of patients with and without postoperative nausea (PON). J Perianesth Nurs. 2012;27:252-258. 14. Hooper VD. SAMBA consensus guidelines for the management of postoperative nausea and vomiting: An executive summary for perianesthesia nurses. J Perianesth Nurs. 2015; 30:377-382. 15. Apfel CC, Kranke P, Eberhart LH, Roos A, Roewer N. Comparison of predictive models for postoperative nausea and vomiting. Br J Anaesth. 2002;88:234-240.

10

16. Apfel CC, Stoecklein K, Lipfert P. PONV: A problem of inhalational anaesthesia? Best Pract Res Clin Anaesthesiol. 2005;19:485-500. 17. Moon YE. Postoperative nausea and vomiting. Korean J Anesthesiol. 2014;67:164-170. 18. Apfel CC, Philip BK, Cakmakkaya OS, et al. Who is at risk for postdischarge nausea and vomiting after ambulatory surgery? Anesthesiology. 2012;117:475-486. 19. Rhodes VA, McDaniel RW. The index of nausea, vomiting, and retching: A new format of the index of nausea and vomiting. Oncol Nurs Forum. 1999;26:889-894. 20. Kim TH, Choi BM, Chin JH, Lee MS, Kim DH, Noh GJ. The reliability and validity of the Rhodes Index of nausea, vomiting and retching in postoperative nausea and vomiting. Korean J Anesthesiol. 2007;52:S59-S65. 21. Collins AS. Postoperative nausea and vomiting in adults: Implications for critical care. Crit Care Nurse. 2001;31:36-45. 22. Grief R, Laciny S, Rapf B, Hickle RS, Sessler DI. Supplemental oxygen reduces the incidence of postoperative nausea and vomiting. Anesthesiology. 1999;91:1246-1252.

SON AND YOON 23. Apfe CC, Greim C, Haubitz I, et al. A risk score to predict the probability of postoperative vomiting in adult. Acta Anaesthesiol Scand. 1998;42:495-501. 24. Brattwall M, Warren-Stomberg M, Rawal N, Segerdahl M, Houltz E, Jakobsson J. Postoperative impact of regular tobacco use, smoking or snuffing, a prospective multi-center study. Acta Anaesthesiol Scand. 2010;54:321-327. 25. Kharasch ED, Hankins DC, Cox K. Clinical isoflurane metabolism by cytochrome P450 2E1. Anesthesiology. 1999; 90:766-771. 26. Kharasch ED, Thummel KE. Identification of cytochrome P450 2E1 as the predominant enzyme catalyzing human liver microsomal defluorination of sevoflurane, isoflurane, and methoxyflurane. Anesthesiology. 1993;79:795-807. 27. Zevin S, Benowitz NL. Drug interactions with tobacco smoking. An update. Clin Pharmacokinet. 1999; 36:425-438. 28. Lockwood G. Theoretical context-sensitive elimination times for inhalation anaesthetics. Br J Anaesth. 2010;104: 648-655.