<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.3 20070202//EN" "journalpublishing.dtd">
<article article-type="research-article" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xml:lang="EN">
<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Surg.</journal-id>
<journal-title>Frontiers in Surgery</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Surg.</abbrev-journal-title>
<issn pub-type="epub">2296-875X</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fsurg.2023.1120930</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Surgery</subject>
<subj-group>
<subject>Original Research</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Effectiveness of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in predicting the incidence of nausea and vomiting after total knee arthroplasty in patients with hemophilia A</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author"><name><surname>Feng</surname><given-names>Denghe</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<xref ref-type="author-notes" rid="an1"><sup>&#x2020;</sup></xref><uri xlink:href="https://loop.frontiersin.org/people/2098190/overview"/></contrib>
<contrib contrib-type="author"><name><surname>Wang</surname><given-names>Dong</given-names></name>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<xref ref-type="author-notes" rid="an1"><sup>&#x2020;</sup></xref><uri xlink:href="https://loop.frontiersin.org/people/1117215/overview" /></contrib>
<contrib contrib-type="author"><name><surname>Gu</surname><given-names>Changping</given-names></name>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref><uri xlink:href="https://loop.frontiersin.org/people/1576323/overview" /></contrib>
<contrib contrib-type="author"><name><surname>Lv</surname><given-names>Meng</given-names></name>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib>
<contrib contrib-type="author"><name><surname>Liu</surname><given-names>Zaibo</given-names></name>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib>
<contrib contrib-type="author" corresp="yes"><name><surname>Wang</surname><given-names>Yuelan</given-names></name>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<xref ref-type="corresp" rid="cor1">&#x002A;</xref><uri xlink:href="https://loop.frontiersin.org/people/1554511/overview" /></contrib>
</contrib-group>
<aff id="aff1"><label><sup>1</sup></label><addr-line>School of Anesthesiology</addr-line>, <institution>Weifang Medical University</institution>, <addr-line>Weifang</addr-line>, <country>China</country></aff>
<aff id="aff2"><label><sup>2</sup></label><addr-line>Department of Anesthesiology</addr-line>, <institution>The First Affiliated Hospital of Shandong First Medical University &#x0026; Shandong Provincial Qianfoshan Hospital, Shandong Institute of Anesthesia and Respiratory Critical Medicine</institution>, <addr-line>Jinan</addr-line>, <country>China</country></aff>
<author-notes>
<fn fn-type="edited-by"><p><bold>Edited by:</bold> Raffaele Vitiello, Agostino Gemelli University Polyclinic (IRCCS), Italy</p></fn>
<fn fn-type="edited-by"><p><bold>Reviewed by:</bold> Alessandro El Motassime, Agostino Gemelli University Polyclinic (IRCCS), Italy Edoardo Pasqui, University of Siena, Italy</p></fn>
<corresp id="cor1"><label>&#x002A;</label><bold>Correspondence:</bold> Yuelan Wang <email>wyldgf@163.com</email></corresp>
<fn fn-type="other" id="an1"><label><sup>&#x2020;</sup></label><p>These authors have contributed equally to this work and share first authorship</p></fn>
<fn fn-type="other" id="fn001"><p><bold>Specialty Section:</bold> This article was submitted to Orthopedic Surgery, a section of the journal Frontiers in Surgery</p></fn>
</author-notes>
<pub-date pub-type="epub"><day>17</day><month>04</month><year>2023</year></pub-date>
<pub-date pub-type="collection"><year>2023</year></pub-date>
<volume>10</volume><elocation-id>1120930</elocation-id>
<history>
<date date-type="received"><day>10</day><month>12</month><year>2022</year></date>
<date date-type="accepted"><day>03</day><month>04</month><year>2023</year></date>
</history>
<permissions>
<copyright-statement>&#x00A9; 2023 Feng, Wang, Gu, Lv, Liu and Wang.</copyright-statement>
<copyright-year>2023</copyright-year><copyright-holder>Feng, Wang, Gu, Lv, Liu and Wang</copyright-holder><license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/4.0/">
<p>This is an open-access article distributed under the terms of the <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution License (CC BY)</ext-link>. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p></license>
</permissions>
<abstract><sec><title>Objective</title>
<p>To investigate the ability of preoperative neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) to predict postoperative nausea and vomiting (PONV) after total knee arthroplasty (TKA).</p>
</sec><sec><title>Methods</title>
<p>The clinical data of 108 male patients with hemophilia A who underwent TKA an our institution were collected and analyzed. Confounding factors were adjusted by propensity score matching. The best cutoffs of the NLR and PLR were determined by the area under the receiver operating characteristic curve (ROC). The predictive ability of these indexes was assessed by measuring the sensitivity, specificity, and positive and negative likelihood ratios.</p>
</sec><sec><title>Results</title>
<p>There were significant differences in the use of antiemetics (<italic>p</italic>&#x2009;&#x003D;&#x2009;0.036) and the incidence of nausea (<italic>p</italic>&#x2009;&#x003C;&#x2009;0.001) and vomiting (<italic>p</italic>&#x2009;&#x003D;&#x2009;0.006) between the two groups (NLR &#x003C;2 and &#x2265;2). An increase in preoperative NLR was an independent risk factor for PONV in patients with hemophilia A (<italic>p</italic>&#x2009;&#x003C;&#x2009;0.05). ROC analysis showed that NLR significantly predicted the occurrence of PONV (cutoff value: 2.20, ROC: 0.711, <italic>p</italic>&#x2009;&#x003C;&#x2009;0.001). In turn, the PLR did not strongly predict PONV.</p>
</sec><sec><title>Conclusions</title>
<p>The NLR is an independent risk factor for PONV in patients with hemophilia A and can significantly predict this event. Thus, follow-up monitoring is essential for these patients.</p>
</sec>
</abstract>
<kwd-group>
<kwd>neutrophils</kwd>
<kwd>lymphocytes</kwd>
<kwd>platelets</kwd>
<kwd>hemophilia</kwd>
<kwd>postoperative nausea and vomiting</kwd>
</kwd-group><contract-num rid="cn001">82270093, 82070078</contract-num><contract-num rid="cn002">ZR202010290035</contract-num><contract-num rid="cn003">2019QL015</contract-num><contract-num rid="cn004">ts20190981, tsqn20181244</contract-num><contract-num rid="cn005">ZR2021QH194</contract-num><contract-num rid="cn006">2019WS508</contract-num><contract-sponsor id="cn001">National Natural Science Foundation of China</contract-sponsor><contract-sponsor id="cn002">Key Program of Natural Science Foundation of Shandong Province</contract-sponsor><contract-sponsor id="cn003">The Academic Promotion Programme of Shandong First Medical University</contract-sponsor><contract-sponsor id="cn004">Taishan Scholars</contract-sponsor><contract-sponsor id="cn005">Natural Science Foundation of Shandong Province</contract-sponsor><contract-sponsor id="cn006">Medical and Health Science and Technology Development Plan Project of Shandong Province</contract-sponsor><counts>
<fig-count count="1"/>
<table-count count="3"/><equation-count count="0"/><ref-count count="23"/><page-count count="0"/><word-count count="0"/></counts>
</article-meta>
</front>
<body><sec id="s1" sec-type="intro"><label>1.</label><title>Introduction</title>
<p>Hemophilic arthropathy is a debilitating complication of hemophilia, leading to intra-articular hemorrhage, especially in knee joints (<xref ref-type="bibr" rid="B1">1</xref>). Total knee arthroplasty (TKA) is the standard treatment for end-stage hemophilic arthropathy (<xref ref-type="bibr" rid="B2">2</xref>). General anesthesia is the preferred anesthetic method for patients with hemophilia because the risk of bleeding is lower than that of neuraxial anesthesia. However, general anesthesia causes postoperative nausea and vomiting (PONV) in 20&#x0025;&#x2013;30&#x0025; of surgical patients (<xref ref-type="bibr" rid="B3">3</xref>). The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are used for the diagnosis and follow-up of inflammatory diseases (<xref ref-type="bibr" rid="B4">4</xref>). The mechanism that causes nausea has not been studied to a large extent. The vomiting reflex seems to originate from the vomiting center located in the dorsolateral medulla oblongata. Inflammation is known to increase the risk of PONV (<xref ref-type="bibr" rid="B5">5</xref>). However, the ability of these indexes to predict PONV in patients with hemophilia has not been assessed. This study retrospectively analyzed the clinical data of patients with hemophilia A and assessed the ability of preoperative NLR and PLR to predict PONV after TKA.</p>
</sec>
<sec id="s2" sec-type="methods"><label>2.</label><title>Methods</title>
<sec id="s2a"><label>2.1.</label><title>Study design</title>
<p>This retrospective study included 108 male patients who underwent TKA at the First Affiliated Hospital of Shandong First Medical University, China, from March 2018 to December 2021. The study was approved by the Research Ethics Committee of our institution [XMSB-LL-2022(044)]. The trial was registered at <ext-link ext-link-type="uri" xlink:href="chictr.org.cn">chictr.org.cn</ext-link> on January 27, 2021 (Registration No: NCT05636163; principal investigator: YW).</p>
</sec>
<sec id="s2b"><label>2.2.</label><title>Inclusion and exclusion criteria</title>
<p>The inclusion criteria were (1) patients with hemophilia A who underwent unilateral total knee replacement, (2) age of 18&#x2013;70 years, (3) American Society of Anesthesiologists (ASA) physical status I&#x2013;III, (4) no history of mental illness, (5) no history of use of antiemetics and anticholinergic drugs, and (6) no history of serious gastrointestinal diseases. The exclusion criteria were (1) patients who received long-term steroid therapy before surgery, (2) patients requiring more than 2.5&#x2005;mg of neostigmine to reverse neuromuscular blockade, and (3) patients with prior malignancy, malabsorption, morbid obesity, hypogonadism, thyroid and parathyroid diseases, and autoimmune diseases. All patients ceased the intake of solid foods and fluids 6 and 2&#x2005;h before surgery, respectively. All surgeries were performed by the same group of surgeons.</p>
</sec>
<sec id="s2c"><label>2.3.</label><title>Primary and secondary outcomes</title>
<p>The primary outcome was the incidence of PONV, which was defined as the occurrence of nausea or vomiting within 24&#x2005;h after surgery (<xref ref-type="bibr" rid="B5">5</xref>). The secondary outcomes were (1) the dosage of postoperative antiemetics (ondansetron, metoclopramide, and dexamethasone), (2) postoperative visual analog scale scores immediately after returning to the ward, and (3) the use of patient-controlled analgesia (PCA).</p>
</sec>
<sec id="s2d"><label>2.4.</label><title>Sample size calculation</title>
<p>The incidence of PONV was expected to be 30.4&#x0025; and 67.4&#x0025; in the group with NLR &#x003C;2 and &#x2265;2, respectively, with <italic>&#x03B1;</italic> of 0.05 and power of 90&#x0025;. The required sample size was calculated using PASS version 15.0 (NCSS, LLC. Kaysville, Utah, USA). The study required a minimum of 34 patients in each group, and the sample size was increased to 43 patients per group to compensate for the loss to follow-up.</p>
</sec>
<sec id="s2e"><label>2.5.</label><title>Patient allocation and data collection</title>
<p>A total of 108 male patients with hemophilia A who underwent TKA under general anesthesia at our institution were selected and divided into two groups according to NLR values (&#x003C;2 and &#x2265;2), as described previously (<xref ref-type="bibr" rid="B6">6</xref>, <xref ref-type="bibr" rid="B7">7</xref>). Data on age, ASA physical status, smoking history, alcohol consumption, and underlying diseases were collected.</p>
<p>The following data were collected from electronic medical records: sex, age, ASA physical status, body mass index (BMI), past medical history, length of surgery, preoperative neutrophil and lymphocyte count, NLR, PLR, and the use of antiemetic medications (ondansetron, metoclopramide, and dexamethasone).</p>
<p>In detail, the inflammatory markers were analyzed, calculating the NLR and PLR. The NLR and PLR were obtained by dividing the absolute neutrophil and platelet counts by the lymphocyte count.</p>
</sec>
<sec id="s2f"><label>2.6.</label><title>Statistical analysis</title>
<p>Statistical analyses were performed using SPSS version 25.0 (IBM, Chicago, IL, USA) and MedCalc version 20.1.0 (MedCalc Software, Ostend, Belgium). The following factors were adjusted by propensity score matching: age, ASA classification, BMI, smoking history, alcohol consumption, hypertension, diabetes mellitus, and allergy medications (<xref ref-type="bibr" rid="B6">6</xref>).</p>
<p>Normally distributed continuous variables were expressed as mean&#x2009;&#x00B1;&#x2009;standard deviation and compared using a <italic>t</italic>-test. Non-normally distributed continuous variables were expressed as median (quartiles) [M (Q1, Q3)] and compared using the Mann&#x2013;Whitney <italic>U</italic> test. Categorical variables were expressed as percentages and compared using the chi-squared test or Fisher&#x0027;s exact test. Independent risk factors in the univariate analysis (<italic>p&#x2009;</italic>&#x003C;&#x2009;0.05) were expressed as odds ratios and corresponding 95&#x0025; confidence intervals (CIs). The predictive value of NLR and PLR for PONV was assessed by the area under the receiver operating characteristic curve (ROC). Two-sided <italic>p-</italic>values of &#x003C;0.05 were considered statistically significant.</p>
</sec>
</sec>
<sec id="s3" sec-type="results"><label>3.</label><title>Results</title>
<sec id="s3a"><label>3.1.</label><title>Baseline characteristics</title>
<p>There were no significant differences in baseline data between the two groups after adjusting for confounders. Additionally, there were no significant intergroup differences in the use of PCA, tourniquets, or ultrasound-guided saphenous nerve block (<italic>p&#x2009;</italic>&#x003E;&#x2009;0.05) (<xref ref-type="table" rid="T1">Table&#x00A0;1</xref>).</p>
<table-wrap id="T1" position="float"><label>Table 1</label>
<caption><p>Comparison of baseline characteristics and surgical information between the two groups of patients.</p></caption>
<table frame="hsides" rules="groups">
<colgroup>
<col align="left"/>
<col align="left"/>
<col align="center"/>
<col align="center"/>
<col align="center"/>
</colgroup>
<thead>
<tr>
<th valign="top" align="left" colspan="2"/>
<th valign="top" align="center">Group1 
(NLR&#x2009;&#x003C;&#x2009;2)</th>
<th valign="top" align="center">Group 2 
(NLR&#x2009;&#x2265;&#x2009;2)</th>
<th valign="top" align="center"><italic>p</italic>-value</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left"><italic>N</italic></td>
<td valign="top" align="left"/>
<td valign="top" align="center">43</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left">Age</td>
<td valign="top" align="left">Years</td>
<td valign="top" align="center">31.28&#x2009;&#x00B1;&#x2009;8.81</td>
<td valign="top" align="center">31.77&#x2009;&#x00B1;&#x2009;7.93</td>
<td valign="top" align="center">0.825a</td>
</tr>
<tr>
<td valign="top" align="left">BMI</td>
<td valign="top" align="left"/>
<td valign="top" align="center">22.81&#x2009;&#x00B1;&#x2009;4.14</td>
<td valign="top" align="center">22.83&#x2009;&#x00B1;&#x2009;3.96</td>
<td valign="top" align="center">0.983a</td>
</tr>
<tr>
<td valign="top" align="left">Operation time</td>
<td valign="top" align="left">Hours</td>
<td valign="top" align="center">2.15&#x2009;&#x00B1;&#x2009;0.76</td>
<td valign="top" align="center">2.41&#x2009;&#x00B1;&#x2009;0.85</td>
<td valign="top" align="center">0.149a</td>
</tr>
<tr>
<td valign="top" align="left">VAS</td>
<td valign="top" align="left"/>
<td valign="top" align="center">2.63&#x2009;&#x00B1;&#x2009;1.69</td>
<td valign="top" align="center">2.40&#x2009;&#x00B1;&#x2009;1.35</td>
<td valign="top" align="center">0.397b</td>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">ASA</td>
<td valign="top" align="left">II</td>
<td valign="top" align="center">29</td>
<td valign="top" align="center">30</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">III</td>
<td valign="top" align="center">14</td>
<td valign="top" align="center">13</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Smoking</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">0</td>
<td valign="top" align="center">1</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center">42</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Alcohol</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">0</td>
<td valign="top" align="center">1</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center">42</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Hypertension</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">3</td>
<td valign="top" align="center">3</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">40</td>
<td valign="top" align="center">40</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Diabetes</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">0</td>
<td valign="top" align="center">0</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Allergy</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">9</td>
<td valign="top" align="center">10</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">34</td>
<td valign="top" align="center">33</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">PCA</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">17</td>
<td valign="top" align="center">20</td>
<td valign="top" align="center">0.663c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">26</td>
<td valign="top" align="center">23</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Tourniquet</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">31</td>
<td valign="top" align="center">29</td>
<td valign="top" align="center">0.815c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">12</td>
<td valign="top" align="center">14</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Saphenous nerve block</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">7</td>
<td valign="top" align="center">7</td>
<td valign="top" align="center">1.000c</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">36</td>
<td valign="top" align="center">36</td>
<td valign="top" align="center"/>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn id="table-fn1"><p>BMI, body mass index; PCA, patient controlled analgesia; a, paired two-sample t-test; b, Wilcoxon signed rank sum test; c, chi-square test.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec id="s3b"><label>3.2.</label><title>Postoperative use of antiemetics and incidence of PONV</title>
<p>There were significant differences in the postoperative use of antiemetics and the incidence of nausea and vomiting between the two groups (NLR&#x2009;&#x2265;&#x2009;2 and NLR&#x2009;&#x003C;&#x2009;2) (<italic>p&#x2009;</italic>&#x003D;&#x2009;0.036, <italic>p&#x2009;</italic>&#x003C;&#x2009;0.001, and <italic>p&#x2009;</italic>&#x003D;&#x2009;0.006, respectively) (<xref ref-type="table" rid="T2">Table&#x00A0;2</xref>). Five (11.6&#x0025;) and fourteen (32.6&#x0025;) patients in the group with NLR&#x2009;&#x003C;&#x2009;2 and NLR&#x2009;&#x2265;&#x2009;2, respectively, used antiemetic medications. In the group with NLR&#x2009;&#x003C;&#x2009;2, 6 (14.0&#x0025;) patients had nausea or vomiting, and 37 (86.0&#x0025;) had none of these complications. In the group with NLR&#x2009;&#x2265;&#x2009;2, 24 (55.8&#x0025;) patients had nausea or vomiting, and 19 (44.2&#x0025;) had none of these complications (<xref ref-type="table" rid="T2">Table&#x00A0;2</xref>).</p>
<table-wrap id="T2" position="float"><label>Table 2</label>
<caption><p>Comparison of postoperative use of antiemetics and incidence of PONV in two groups.</p></caption>
<table frame="hsides" rules="groups">
<colgroup>
<col align="left"/>
<col align="left"/>
<col align="center"/>
<col align="center"/>
<col align="center"/>
</colgroup>
<thead>
<tr>
<th valign="top" align="left" colspan="2"/>
<th valign="top" align="center">Group 1 
(NLR&#x2009;&#x003C;&#x2009;2)</th>
<th valign="top" align="center">Group 2 
(NLR&#x2009;&#x2265;&#x2009;2)</th>
<th valign="top" align="center"><italic>p</italic>-value</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left"><italic>N</italic></td>
<td valign="top" align="left"/>
<td valign="top" align="center">43</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Antiemetic use in 24&#x2005;h</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">5</td>
<td valign="top" align="center">14</td>
<td valign="top" align="center">0.036</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">38</td>
<td valign="top" align="center">29</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Nausea</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">6</td>
<td valign="top" align="center">24</td>
<td valign="top" align="center">&#x003C;0.001</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">37</td>
<td valign="top" align="center">19</td>
<td valign="top" align="center"/>
</tr>
<tr>
<td valign="top" align="left" rowspan="2">Vomiting</td>
<td valign="top" align="left">Yes</td>
<td valign="top" align="center">5</td>
<td valign="top" align="center">17</td>
<td valign="top" align="center">0.006</td>
</tr>
<tr>
<td valign="top" align="left">No</td>
<td valign="top" align="center">38</td>
<td valign="top" align="center">26</td>
<td valign="top" align="center"/>
</tr>
</tbody>
</table>
</table-wrap>
</sec>
<sec id="s3c"><label>3.3.</label><title>Analysis of factors influencing the occurrence of PONV</title>
<p>The poor prognosis of patients with PONV was considered the dependent variable, and age, ASA physical status, length of surgery, BMI, use of PCA and tourniquets, ultrasound-guided saphenous nerve block, preoperative NLR, and PLR level from lowest to highest were assigned in the univariate logistic regression analysis. The results showed that increased preoperative NLR was an independent risk factor for the development of PONV (<italic>p&#x2009;</italic>&#x003C;&#x2009;0.05) (<xref ref-type="table" rid="T3">Table&#x00A0;3</xref>).</p>
<table-wrap id="T3" position="float"><label>Table 3</label>
<caption><p>Univariate logistic regression analysis of factors associated with the occurrence of PONV in patients with hemophilia A.</p></caption>
<table frame="hsides" rules="groups">
<colgroup>
<col align="left"/>
<col align="left"/>
<col align="center"/>
<col align="center"/>
<col align="center"/>
</colgroup>
<thead>
<tr>
<th valign="top" align="left" colspan="2"/>
<th valign="top" align="center">Odds ratio</th>
<th valign="top" align="center">95&#x0025; confidence interval</th>
<th valign="top" align="center"><italic>p</italic>-value</th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">Age</td>
<td valign="top" align="left">Years</td>
<td valign="top" align="center">0.992</td>
<td valign="top" align="center">0.927&#x2013;1.063</td>
<td valign="top" align="center">0.828</td>
</tr>
<tr>
<td valign="top" align="left">BMI</td>
<td valign="top" align="left"/>
<td valign="top" align="center">0.950</td>
<td valign="top" align="center">0.828&#x2013;1.090</td>
<td valign="top" align="center">0.465</td>
</tr>
<tr>
<td valign="top" align="left">Operation time</td>
<td valign="top" align="left">Hours</td>
<td valign="top" align="center">1.421</td>
<td valign="top" align="center">0.685&#x2013;2.946</td>
<td valign="top" align="center">0.345</td>
</tr>
<tr>
<td valign="top" align="left">NLR</td>
<td valign="top" align="left"/>
<td valign="top" align="center">2.603</td>
<td valign="top" align="center">1.047&#x2013;6.472</td>
<td valign="top" align="center">0.040</td>
</tr>
<tr>
<td valign="top" align="left">PLR</td>
<td valign="top" align="left"/>
<td valign="top" align="center">0.999</td>
<td valign="top" align="center">0.985&#x2013;1.013</td>
<td valign="top" align="center">0.861</td>
</tr>
<tr>
<td valign="top" align="left">PCA</td>
<td valign="top" align="left"/>
<td valign="top" align="center">1.660</td>
<td valign="top" align="center">0.499&#x2013;5.516</td>
<td valign="top" align="center">0.408</td>
</tr>
<tr>
<td valign="top" align="left">Tourniquet</td>
<td valign="top" align="left"/>
<td valign="top" align="center">1.988</td>
<td valign="top" align="center">0.501&#x2013;7.889</td>
<td valign="top" align="center">0.329</td>
</tr>
<tr>
<td valign="top" align="left">Saphenous nerve block</td>
<td valign="top" align="left"/>
<td valign="top" align="center">1.758</td>
<td valign="top" align="center">0.412&#x2013;7.490</td>
<td valign="top" align="center">0.446</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn id="table-fn2"><p>NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec id="s3d"><label>3.4.</label><title>ROC analysis of NLR and PLR</title>
<p>The ROC showed that NLR could significantly predict PONV (ROC: 0.711, 95&#x0025; CI: 0.603&#x2013;0.803, <italic>p&#x2009;</italic>&#x003C;&#x2009;0.001). The Youden index was highest (0.5012) at an NLR&#x2009;&#x003E;&#x2009;2.20, with a sensitivity of 0.733 (95&#x0025; CI: 0.541&#x2013;0.877), specificity of 0.770 (95&#x0025; CI: 0.636&#x2013;0.870), positive likelihood ratio of 3.16, and negative likelihood ratio of 0.35. PLR could not significantly predict PONV (ROC: 0.603, 95&#x0025; CI: 0.492&#x2013;0.707, <italic>p</italic>&#x2009;&#x003D;&#x2009;0.112) (<xref ref-type="fig" rid="F1">Figures&#x00A0;1A,B</xref>).</p>
<fig id="F1" position="float"><label>Figure 1</label>
<caption><p>(<bold>A</bold>) ROC curve of PONV diagnosis predicted by NLR parameters; (<bold>B</bold>) ROC curve of PONV diagnosis predicted by PLR parameters. ROC, receiver operating characteristic curve; PONV, postoperative nausea and vomiting; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ration..</p></caption>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="fsurg-10-1120930-g001.tif"/>
</fig>
</sec>
</sec>
<sec id="s4" sec-type="discussion"><label>4.</label><title>Discussion</title>
<p>In this study, laboratory indicators NLR and PLR were collected to determine whether they could predict the occurrence of nausea and vomiting in patients with hemophilia. The study found that NLR was an independent risk factor for PONV after adjusting for confounders. The ROC analysis showed that NLR could accurately predict the occurrence of PONV.</p>
<p>The centers of the autonomic nervous system associated with vomiting are at the level of the medulla oblongata in the hindbrain. Chemo-sensitive receptors detect substances in the blood and transmit this information to the adjacent nucleus of the solitary tract in the hindbrain region (<xref ref-type="bibr" rid="B8">8</xref>). Inflammatory mediators may affect nausea and vomiting centers through blood circulation. In previous literature, studies have used NLR and PLR as inflammatory parameters to determine the prognosis of some diseases, such as heart disease, vascular disease and tumor (<xref ref-type="bibr" rid="B9">9</xref>&#x2013;<xref ref-type="bibr" rid="B11">11</xref>). The NLR is a parameter for the diagnosis and follow-up of inflammatory diseases and surgical outcomes. Additionally, NLR is a marker for PONV in patients undergoing maxillofacial surgery (<xref ref-type="bibr" rid="B7">7</xref>). Tayfur et al. evaluated the relationship between the platelet-lymphocyte ratio and hyperemesis gravidarum in 433 patients and 160 controls (<xref ref-type="bibr" rid="B12">12</xref>). NLR and PLR can predict PONV in patients undergoing breast reduction surgery (<xref ref-type="bibr" rid="B13">13</xref>). A PLR cutoff of 137.2 could significantly predict PONV, and the sensitivity of this PLR value for predicting PONV was higher than that of NLR (77.8&#x0025; vs. 73.3&#x0025;). The ROC analysis showed that the ability of PLR to predict PONV was higher than that of NLR. In our cohort, preoperative NLR with a cutoff of 2.20 significantly predicted the occurrence of PONV; however, preoperative PLR did not accurately predict PONV in our patients. This result may be related to the small sample size. Thus, large prospective studies are needed to confirm this relationship.</p>
<p>PONV is a common postoperative symptom. The incidence of PONV is 30&#x0025;&#x2013;50&#x0025; in surgical patients and up to 80&#x0025; in high-risk patients (<xref ref-type="bibr" rid="B14">14</xref>, <xref ref-type="bibr" rid="B15">15</xref>). Hemophilia is characterized by reduced levels of coagulation factors (<xref ref-type="bibr" rid="B16">16</xref>). Gastrointestinal bleeding is probably the most challenging event in hemophiliacs. Vascular dysplasia along with postoperative vomiting is likely to trigger gastrointestinal bleeding when coagulation factors are deficient or have reduced activity (<xref ref-type="bibr" rid="B17">17</xref>). Therefore, this study assessed PONV in these patients.</p>
<p>Ondansetron is the most commonly used 5-hydroxytryptamine receptor antagonist and is the gold standard for PONV therapy (Evidence A1) (<xref ref-type="bibr" rid="B18">18</xref>). The United States Food and Drug Administration recommends doses smaller than 16&#x2005;mg for chemotherapy-induced nausea and vomiting because of the risk of prolongation of the QT interval (<xref ref-type="bibr" rid="B19">19</xref>). Metoclopramide has antiemetic effects at doses larger than 20&#x2005;mg (<xref ref-type="bibr" rid="B20">20</xref>). In our study, based on follow-up and historical recommendation two of the patients who experienced vomiting were given 10&#x2005;mg of metoclopramide with poor results, and the addition of 8&#x2005;mg of ondansetron relieved symptoms, supporting the evidence for increased metoclopramide use.</p>
<p>Achieving adequate analgesia after TKA is challenging, and different multimodal analgesic regimens are effective (<xref ref-type="bibr" rid="B21">21</xref>). We can use PCA or ultrasound-guided saphenous nerve blocks for postoperative analgesia, but saphenous nerve blocks carry the risk of puncturing blood vessels and are not conducive to postoperative recovery. In our cohort, PCA was used by 37 patients postoperatively. Postoperative opioid use is a strong predictor of PONV development (<xref ref-type="bibr" rid="B3">3</xref>). Various antiemetic drugs reduce PONV (<xref ref-type="bibr" rid="B22">22</xref>), so we routinely use ondansetron 8&#x2005;mg for this purpose. In our cohort, 30 patients had vomiting, and the incidence of PONV was significantly higher in the group with NLR&#x2009;&#x003E;&#x2009;2. The current evidence for recommending two or more antiemetics for preventing PONV is strong, and combination therapy is superior to monotherapy (<xref ref-type="bibr" rid="B23">23</xref>).</p>
<p>This study has limitations. First, we analyzed data from a single center, the sample size was small, and the study was retrospective in nature. Second, preoperative nausea and vomiting symptoms were based on patient-reported responses, and the incidence of symptoms might be underestimated because of recall bias. However, adjusting confounding factors for postoperative outcomes by propensity score matching reduced the bias in this study.</p>
</sec>
<sec id="s5" sec-type="conclusions"><label>5.</label><title>Conclusion</title>
<p>NLR has good ability to predict PONV after TKA in patients with hemophilia A. Thus, blood parameters should be analyzed to improve surgical outcomes in these patients. However, this result needs to be confirmed by larger studies.</p>
</sec>
</body>
<back>
<sec id="s6" sec-type="data-availability"><title>Data availability statement</title>
<p>The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.</p>
</sec>
<sec id="s7"><title>Ethics statement</title>
<p>The studies involving human participants were reviewed and approved by Medical Ethics Committee of the First Affiliated Hospital of Shandong First Medical University (Shandong Provincial Qianfoshan Hospital). Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.</p>
</sec>
<sec id="s8"><title>Author contributions</title>
<p>YW designed and supervised the study; YW and DW obtained funding; DF designed and drafted the study protocol and wrote the manuscript. DF, DW, CG, ML, and ZL executed the study. All authors contributed to the article and approved the submitted version.</p>
</sec>
<sec id="s9" sec-type="funding-information"><title>Funding</title>
<p>This work was supported by the National Natural Science Foundation of China (82270093, 82070078), the Key Program of Natural Science Foundation of Shandong Province (ZR202010290035), The Academic Promotion Programme of Shandong First Medical University (2019QL015), Taishan Scholars (ts20190981, tsqn20181244), and the Natural Science Foundation of Shandong Province (ZR2021QH194), and the Medical and Health Science and Technology Development Plan Project of Shandong Province (2019WS508)</p>
</sec>
<ack><title>Acknowledgments</title>
<p>We thank the staff at the Center for Big Data Research in Health and Medicine, First Affiliated Hospital of Shandong First Medical University (Shandong Provincial Qianfoshan Hospital), China, for helpful assistance.</p>
</ack>
<sec id="s10" sec-type="COI-statement"><title>Conflict of interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec id="s11" sec-type="disclaimer"><title>Publisher&#x0027;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
<ref-list><title>References</title>
<ref id="B1"><label>1.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Mortazavi</surname><given-names>SM</given-names></name><name><surname>Haghpanah</surname><given-names>B</given-names></name><name><surname>Ebrahiminasab</surname><given-names>MM</given-names></name><name><surname>Baghdadi</surname><given-names>T</given-names></name><name><surname>Toogeh</surname><given-names>G</given-names></name></person-group>. <article-title>Functional outcome of total knee arthroplasty in patients with haemophilia</article-title>. <source>Haemophilia</source>. (<year>2016</year>) <volume>22</volume>(<issue>6</issue>):<fpage>919</fpage>&#x2013;<lpage>24</lpage>. <pub-id pub-id-type="doi">10.1111/hae.12999</pub-id><pub-id pub-id-type="pmid">27561958</pub-id></citation></ref>
<ref id="B2"><label>2.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Rodriguez-Merchan</surname><given-names>EC</given-names></name></person-group>. <article-title>Total knee replacement in haemophilic arthropathy</article-title>. <source>J Bone Joint Surg Br</source>. (<year>2007</year>) <volume>89</volume>(<issue>2</issue>):<fpage>186</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.1302/0301-620X.89B2.18682</pub-id><pub-id pub-id-type="pmid">17322432</pub-id></citation></ref>
<ref id="B3"><label>3.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Apfel</surname><given-names>CC</given-names></name><name><surname>Heidrich</surname><given-names>FM</given-names></name><name><surname>Jukar-Rao</surname><given-names>S</given-names></name><name><surname>Jalota</surname><given-names>L</given-names></name><name><surname>Hornuss</surname><given-names>C</given-names></name><name><surname>Whelan</surname><given-names>RP</given-names></name><etal/></person-group> <article-title>Evidence-based analysis of risk factors for postoperative nausea and vomiting</article-title>. <source>Br J Anaesth</source>. (<year>2012</year>) <volume>109</volume>(<issue>5</issue>):<fpage>742</fpage>&#x2013;<lpage>53</lpage>. <pub-id pub-id-type="doi">10.1093/bja/aes276</pub-id><pub-id pub-id-type="pmid">23035051</pub-id></citation></ref>
<ref id="B4"><label>4.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Shimoyama</surname><given-names>Y</given-names></name><name><surname>Umegaki</surname><given-names>O</given-names></name><name><surname>Agui</surname><given-names>T</given-names></name><name><surname>Kadono</surname><given-names>N</given-names></name><name><surname>Minami</surname><given-names>T</given-names></name></person-group>. <article-title>Neutrophil to lymphocyte ratio and platelet to lymphocyte ratio are superior to other inflammation-based prognostic scores in predicting the mortality of patients with gastrointestinal perforation</article-title>. <source>JA Clin Rep</source>. (<year>2017</year>) <volume>3</volume>(<issue>1</issue>):<fpage>49</fpage>. <pub-id pub-id-type="doi">10.1186/s40981-017-0118-1</pub-id><pub-id pub-id-type="pmid">29457093</pub-id></citation></ref>
<ref id="B5"><label>5.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Jahromi</surname><given-names>HE</given-names></name><name><surname>Gholami</surname><given-names>M</given-names></name><name><surname>Rezaei</surname><given-names>F</given-names></name></person-group>. <article-title>A randomized double-blinded placebo controlled study of four interventions for the prevention of postoperative nausea and vomiting in maxillofacial trauma surgery</article-title>. <source>J Craniofac Surg</source>. (<year>2013</year>) <volume>24</volume>(<issue>6</issue>):<fpage>e623</fpage>&#x2013;<lpage>7</lpage>. <pub-id pub-id-type="doi">10.1097/SCS.0b013e3182a2d896</pub-id><pub-id pub-id-type="pmid">24220487</pub-id></citation></ref>
<ref id="B6"><label>6.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Yildiz Altun</surname><given-names>A</given-names></name><name><surname>Demirel</surname><given-names>I</given-names></name><name><surname>Bolat</surname><given-names>E</given-names></name><name><surname>Ozcan</surname><given-names>S</given-names></name><name><surname>Altun</surname><given-names>S</given-names></name><name><surname>Aksu</surname><given-names>A</given-names></name><etal/></person-group> <article-title>The relationship between the preoperative neutrophil-to-lymphocyte ratio and postoperative nausea and vomiting in patients undergoing septorhinoplasty surgery</article-title>. <source>Aesthetic Plast Surg</source>. (<year>2019</year>) <volume>43</volume>(<issue>3</issue>):<fpage>861</fpage>&#x2013;<lpage>5</lpage>. <pub-id pub-id-type="doi">10.1007/s00266-019-01325-5</pub-id><pub-id pub-id-type="pmid">30767038</pub-id></citation></ref>
<ref id="B7"><label>7.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Arpaci</surname><given-names>AH</given-names></name><name><surname>Isik</surname><given-names>B</given-names></name><name><surname>Ilhan</surname><given-names>E</given-names></name><name><surname>Erdem</surname><given-names>E</given-names></name></person-group>. <article-title>Association of postoperative nausea and vomiting incidence with neutrophil-lymphocyte ratio in ambulatory maxillofacial surgery</article-title>. <source>J Oral Maxillofac Surg</source>. (<year>2017</year>) <volume>75</volume>(<issue>7</issue>):<fpage>1367</fpage>&#x2013;<lpage>71</lpage>. <pub-id pub-id-type="doi">10.1016/j.joms.2016.12.036</pub-id><pub-id pub-id-type="pmid">28137634</pub-id></citation></ref>
<ref id="B8"><label>8.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Hornby</surname><given-names>PJ</given-names></name></person-group>. <article-title>Central neurocircuitry associated with emesis</article-title>. <source>Am J Med</source>. (<year>2001</year>) <volume>111</volume>(<issue>Suppl 8A</issue>):<fpage>106s</fpage>&#x2013;<lpage>12s</lpage>. <pub-id pub-id-type="doi">10.1016/S0002-9343(01)00849-X</pub-id><pub-id pub-id-type="pmid">11749934</pub-id></citation></ref>
<ref id="B9"><label>9.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Pasqui</surname><given-names>E</given-names></name><name><surname>de Donato</surname><given-names>G</given-names></name><name><surname>Lazzeri</surname><given-names>E</given-names></name><name><surname>Molino</surname><given-names>C</given-names></name><name><surname>Galzerano</surname><given-names>G</given-names></name><name><surname>Giubbolini</surname><given-names>M</given-names></name><etal/></person-group> <article-title>High neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios are associated with a higher risk of hemodialysis vascular access failure</article-title>. <source>Biomedicines</source>. (<year>2022</year>) <volume>10</volume>(<issue>9</issue>):<fpage>2218</fpage>. <pub-id pub-id-type="doi">10.3390/biomedicines10092218</pub-id><pub-id pub-id-type="pmid">36140317</pub-id></citation></ref>
<ref id="B10"><label>10.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Azab</surname><given-names>B</given-names></name><name><surname>Zaher</surname><given-names>M</given-names></name><name><surname>Weiserbs</surname><given-names>KF</given-names></name><name><surname>Torbey</surname><given-names>E</given-names></name><name><surname>Lacossiere</surname><given-names>K</given-names></name><name><surname>Gaddam</surname><given-names>S</given-names></name><etal/></person-group> <article-title>Usefulness of neutrophil to lymphocyte ratio in predicting short- and long-term mortality after non-ST-elevation myocardial infarction</article-title>. <source>Am J Cardiol</source>. (<year>2010</year>) <volume>106</volume>(<issue>4</issue>):<fpage>470</fpage>&#x2013;<lpage>6</lpage>. <pub-id pub-id-type="doi">10.1016/j.amjcard.2010.03.062</pub-id><pub-id pub-id-type="pmid">20691303</pub-id></citation></ref>
<ref id="B11"><label>11.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Shimada</surname><given-names>H</given-names></name><name><surname>Takiguchi</surname><given-names>N</given-names></name><name><surname>Kainuma</surname><given-names>O</given-names></name><name><surname>Soda</surname><given-names>H</given-names></name><name><surname>Ikeda</surname><given-names>A</given-names></name><name><surname>Cho</surname><given-names>A</given-names></name><etal/></person-group> <article-title>High preoperative neutrophil-lymphocyte ratio predicts poor survival in patients with gastric cancer</article-title>. <source>Gastric Cancer</source>. (<year>2010</year>) <volume>13</volume>(<issue>3</issue>):<fpage>170</fpage>&#x2013;<lpage>6</lpage>. <pub-id pub-id-type="doi">10.1007/s10120-010-0554-3</pub-id><pub-id pub-id-type="pmid">20820986</pub-id></citation></ref>
<ref id="B12"><label>12.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Tayfur</surname><given-names>C</given-names></name><name><surname>Burcu</surname><given-names>DC</given-names></name><name><surname>Gulten</surname><given-names>O</given-names></name><name><surname>Betul</surname><given-names>D</given-names></name><name><surname>Tugberk</surname><given-names>G</given-names></name><name><surname>Onur</surname><given-names>O</given-names></name><etal/></person-group> <article-title>Association between platelet to lymphocyte ratio, plateletcrit and the presence and severity of hyperemesis gravidarum</article-title>. <source>J Obstet Gynaecol Res</source>. (<year>2017</year>) <volume>43</volume>(<issue>3</issue>):<fpage>498</fpage>&#x2013;<lpage>504</lpage>. <pub-id pub-id-type="doi">10.1111/jog.13228</pub-id><pub-id pub-id-type="pmid">28160526</pub-id></citation></ref>
<ref id="B13"><label>13.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Karaca</surname><given-names>O</given-names></name><name><surname>Dogan</surname><given-names>G</given-names></name></person-group>. <article-title>Can neutrophil-to-lymphocyte or platelet-to-lymphocyte ratio be used to predict postoperative nausea and vomiting in breast reduction?</article-title> <source>Cureus</source>. (<year>2020</year>) <volume>12</volume>(<issue>3</issue>):<fpage>e7237</fpage>. <pub-id pub-id-type="doi">10.7759/cureus.7237</pub-id><pub-id pub-id-type="pmid">32284913</pub-id></citation></ref>
<ref id="B14"><label>14.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Sinclair</surname><given-names>DR</given-names></name><name><surname>Chung</surname><given-names>F</given-names></name><name><surname>Mezei</surname><given-names>G</given-names></name></person-group>. <article-title>Can postoperative nausea and vomiting be predicted?</article-title> <source>Anesthesiology</source>. (<year>1999</year>) <volume>91</volume>(<issue>1</issue>):<fpage>109</fpage>&#x2013;<lpage>18</lpage>. <pub-id pub-id-type="doi">10.1097/00000542-199907000-00018</pub-id><pub-id pub-id-type="pmid">10422935</pub-id></citation></ref>
<ref id="B15"><label>15.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Czarnetzki</surname><given-names>C</given-names></name><name><surname>Schiffer</surname><given-names>E</given-names></name><name><surname>Lysakowski</surname><given-names>C</given-names></name><name><surname>Haller</surname><given-names>G</given-names></name><name><surname>Bertrand</surname><given-names>D</given-names></name><name><surname>Tram&#x00E8;r</surname><given-names>MR</given-names></name></person-group>. <article-title>Transcutaneous nicotine does not prevent postoperative nausea and vomiting: a randomized controlled trial</article-title>. <source>Br J Clin Pharmacol</source>. (<year>2011</year>) <volume>71</volume>(<issue>3</issue>):<fpage>383</fpage>&#x2013;<lpage>90</lpage>. <pub-id pub-id-type="doi">10.1111/j.1365-2125.2010.03844.x</pub-id><pub-id pub-id-type="pmid">21284697</pub-id></citation></ref>
<ref id="B16"><label>16.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Peyvandi</surname><given-names>F</given-names></name><name><surname>Garagiola</surname><given-names>I</given-names></name><name><surname>Young</surname><given-names>G</given-names></name></person-group>. <article-title>The past and future of haemophilia: diagnosis, treatments, and its complications</article-title>. <source>Lancet</source>. (<year>2016</year>) <volume>388</volume>(<issue>10040</issue>):<fpage>187</fpage>&#x2013;<lpage>97</lpage>. <pub-id pub-id-type="doi">10.1016/S0140-6736(15)01123-X</pub-id><pub-id pub-id-type="pmid">26897598</pub-id></citation></ref>
<ref id="B17"><label>17.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Franchini</surname><given-names>M</given-names></name><name><surname>Mannucci</surname><given-names>PM</given-names></name></person-group>. <article-title>Gastrointestinal angiodysplasia and bleeding in von willebrand disease</article-title>. <source>Thromb Haemost</source>. (<year>2014</year>) <volume>112</volume>(<issue>3</issue>):<fpage>427</fpage>&#x2013;<lpage>31</lpage>. <pub-id pub-id-type="doi">10.1160/TH13-11-0952</pub-id><pub-id pub-id-type="pmid">24898873</pub-id></citation></ref>
<ref id="B18"><label>18.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Tricco</surname><given-names>AC</given-names></name><name><surname>Soobiah</surname><given-names>C</given-names></name><name><surname>Blondal</surname><given-names>E</given-names></name><name><surname>Veroniki</surname><given-names>AA</given-names></name><name><surname>Khan</surname><given-names>PA</given-names></name><name><surname>Vafaei</surname><given-names>A</given-names></name><etal/></person-group> <article-title>Comparative efficacy of serotonin (5-HT3) receptor antagonists in patients undergoing surgery: a systematic review and network meta-analysis</article-title>. <source>BMC Med</source>. (<year>2015</year>) <volume>13</volume>:<fpage>136</fpage>. <pub-id pub-id-type="doi">10.1186/s12916-015-0371-y</pub-id><pub-id pub-id-type="pmid">26084277</pub-id></citation></ref>
<ref id="B19"><label>19.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Gan</surname><given-names>TJ</given-names></name><name><surname>Diemunsch</surname><given-names>P</given-names></name><name><surname>Habib</surname><given-names>AS</given-names></name><name><surname>Kovac</surname><given-names>A</given-names></name><name><surname>Kranke</surname><given-names>P</given-names></name><name><surname>Meyer</surname><given-names>TA</given-names></name><etal/></person-group> <article-title>Consensus guidelines for the management of postoperative nausea and vomiting</article-title>. <source>Anesth Analg</source>. (<year>2014</year>) <volume>118</volume>(<issue>1</issue>):<fpage>85</fpage>&#x2013;<lpage>113</lpage>. <pub-id pub-id-type="doi">10.1213/ANE.0000000000000002</pub-id><pub-id pub-id-type="pmid">24356162</pub-id></citation></ref>
<ref id="B20"><label>20.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Wallenborn</surname><given-names>J</given-names></name><name><surname>Gelbrich</surname><given-names>G</given-names></name><name><surname>Bulst</surname><given-names>D</given-names></name><name><surname>Behrends</surname><given-names>K</given-names></name><name><surname>Wallenborn</surname><given-names>H</given-names></name><name><surname>Rohrbach</surname><given-names>A</given-names></name><etal/></person-group> <article-title>Prevention of postoperative nausea and vomiting by&#x00A0;metoclopramide combined with dexamethasone: randomised double blind&#x00A0;multicentre trial</article-title>. <source>Br Med J</source>. (<year>2006</year>) <volume>333</volume>(<issue>7563</issue>):<fpage>324</fpage>. <pub-id pub-id-type="doi">10.1136/bmj.38903.419549.80</pub-id></citation></ref>
<ref id="B21"><label>21.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Yu</surname><given-names>S</given-names></name><name><surname>Dundon</surname><given-names>J</given-names></name><name><surname>Solovyova</surname><given-names>O</given-names></name><name><surname>Bosco</surname><given-names>J</given-names></name><name><surname>Iorio</surname><given-names>R</given-names></name></person-group>. <article-title>Can multimodal pain management in TKA eliminate patient-controlled analgesia and femoral nerve blocks?</article-title> <source>Clin Orthop Relat Res</source>. (<year>2018</year>) <volume>476</volume>(<issue>1</issue>):<fpage>101</fpage>&#x2013;<lpage>9</lpage>. <pub-id pub-id-type="doi">10.1007/s11999.0000000000000018</pub-id><pub-id pub-id-type="pmid">29529623</pub-id></citation></ref>
<ref id="B22"><label>22.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Tram&#x00E8;r</surname><given-names>MR</given-names></name><name><surname>Walder</surname><given-names>B</given-names></name></person-group>. <article-title>Efficacy and adverse effects of prophylactic antiemetics&#x00A0;during patient-controlled analgesia therapy: a quantitative systematic&#x00A0;review</article-title>. <source>Anesth Analg</source>. (<year>1999</year>) <volume>88</volume>(<issue>6</issue>):<fpage>1354</fpage>&#x2013;<lpage>61</lpage>. <pub-id pub-id-type="doi">10.1213/00000539-199906000-00030</pub-id></citation></ref>
<ref id="B23"><label>23.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Dewinter</surname><given-names>G</given-names></name><name><surname>Staelens</surname><given-names>W</given-names></name><name><surname>Veef</surname><given-names>E</given-names></name><name><surname>Teunkens</surname><given-names>A</given-names></name><name><surname>Van de Velde</surname><given-names>M</given-names></name><name><surname>Rex</surname><given-names>S</given-names></name></person-group>. <article-title>Simplified algorithm for the prevention of postoperative nausea and vomiting: a before-and-after study</article-title>. <source>Br J Anaesth</source>. (<year>2018</year>) <volume>120</volume>(<issue>1</issue>):<fpage>156</fpage>&#x2013;<lpage>63</lpage>. <pub-id pub-id-type="doi">10.1016/j.bja.2017.08.003</pub-id><pub-id pub-id-type="pmid">29397124</pub-id></citation></ref></ref-list>
</back>
</article>