***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose : To test the hypothesis that an experienced surgeon is associated with less postoperative nausea and vomiting ( PONV ) In a double-blind , r and omized study , we have compared the efficacy of transdermal hyoscine in the prevention of nausea and vomiting with placebo in 60 young , ASA I-II patients after middle ear surgery during general anaesthesia . In the placebo group , 27 % and 43 % of patients suffered from nausea and vomiting , respectively , during the first 24 h after anaesthesia . The corresponding values for both symptoms in the hyoscine group were 10 % ( P < 0.001 between groups ) . The frequency of side effects was similar in both groups . The results suggest that transdermal hyoscine is a useful prophylaxis against nausea and vomiting after middle ear surgery Abstract  Variability  in patients ' response to interventions in pain and other clinical setting s is large . Many explanations such as trial methods , environment or culture have been proposed , but this paper sets out to show that the main cause of the variability may be r and om chance , and that if trials are small their estimate of magnitude of effect may be incorrect , simply because of the r and om play of chance . This is highly relevant to the questions of ‘ How large do trials have to be for statistical accuracy ? ’ and ‘ How large do trials have to be for their results to be clinical ly valid ? ’ The true underlying control event rate ( CER ) and experimental event rate ( EER ) were determined from single‐dose acute pain analgesic trials in over 5000 patients . Trial group size required to obtain statistically significant and clinical ly relevant ( 0.95 probability of number‐needed‐to‐treat within ±0.5 of its true value ) results were computed using these values . Ten thous and trials using these CER and EER values were simulated using varying group sizes to investigate the variation due to r and om chance alone . Most common analgesics have EERs in the range 0.4–0.6 and CER of about 0.19 . With such efficacy , to have a 90 % chance of obtaining a statistically significant result in the correct direction requires group sizes in the range 30–60 . For clinical relevance nearly 500 patients are required in each group . Only with an extremely effective drug ( EER>0.8 ) will we be reasonably sure of obtaining a clinical ly relevant NNT with commonly used group sizes of around 40 patients per treatment arm . The simulated trials showed substantial variation in CER and EER , with the probability of obtaining the correct values improving as group size increased . We contend that much of the variability in control and experimental event rates is due to r and om chance alone . Single small trials are unlikely to be correct . If we want to be sure of getting correct ( clinical ly relevant ) results in clinical trials we must study more patients . Credible estimates of clinical efficacy are only likely to come from large trials or from pooling multiple trials of conventional ( small ) size A double‐blind comparison of the effect of Ketogana ( ketobemidone and A‐29 , an anticholincrgic and spasmolytic agent ) and morphine + scopolamine as premedication was performed in 113 women admitted for abortion and in 114 women admitted for gynaecological dilatation and curettage . Anaesthesia was thiopentone and nitrous oxide and oxygen , occasionally supplemented with enflurane . It was found that 1 ml morphine + scopolamine ( 10 mg + 0.4 mg ) was more sedative than 1 ml ketogan ( ketobemidonr 5 mg + A‐29 25 mg ) . After ketogan there was less nausea and dryness of the mouth before induction of anaesthesia than after morphine + scopolamine . Ketogan had the same tranquillizing effect but less hypnotic effect preoperatively than morphine + scopolamine . During the 3‐h postoperative observation period the patients premedicated with ketogan woke up significantly sooner and had more pain than those given morphine + scopolamine . More patients required postoperative antiemetics in the ketogan‐prernedicated group than in the morphine + scopolamine‐premedicated group Drugs with anti-emetic properties can exert their actions at more than one receptor site , histamine H1 , muscarinic cholinergic or dopaminergic D2 receptors . This study was design ed to test the hypothesis that a combination of drugs acting at different receptor sites in lower than st and ard doses would be at least as effective as a st and ard therapeutic dose of a single anti-emetic agent . A combination of droperidol , hyoscine and metoclopramide in subtherapeutic doses has been shown to be at least as effective as droperidol ( 1.25 mg ) alone . In both groups there was a low incidence of emetic sequelae in the first 3 hours postoperatively In a double-blind , r and omized study , we have compared the efficacy of transdermal hyoscine with placebo in the reduction of nausea and vomiting in 50 patients , ASA I-II , after surgical correction of prominent ears under general anaesthesia . In the placebo group , 28 % , 4 % and 48 % of patients suffered nausea , retching and vomiting , respectively , during the first 24 h after anaesthesia . The corresponding values in the hyoscine group were 12 % , 0 % and 16 % ( P < 0.01 ) . In the placebo group more patients ( 48 % ) needed droperidol as an antiemetic compared with the hyoscine group ( 16 % ; P < 0.05 ) . There was significantly more sedation in the hyoscine group In recent decades , the management of patients with suspected acute myocardial infa rct ion ( MI ) has progressed substantially through the testing ( and acceptance or rejection ) of a number of different hypotheses . In the 1960s , recognition of the risks of early ventricular fibrillation led to the establishment of coronary care units , emphasis on early hospitalization of patients , and often , the use of prophylactic antiarrhythmic agents ( e.g. , lidocaine).1,2 Various estimates suggest that these approaches were associated with a substantial reduction in early mortality , but the possibility that at least some part of this apparent benefit was due to the hospitalization of lower-risk individuals can not be ruled out . In the 1970s and early 1980s , the concept of myocardial salvage was extensively evaluated by testing drugs with a variety of different mechanisms of action.3 This included early intravenous 83-blockers , hyaluronidase , nitrates , glucose-insulin potassium , calcium blockers , etc.4 Of these agents , the value of intravenous 13-blockers has been confirmed by large r and omized trials5 and that of intravenous nitrates by meta-analyses of several smaller trials.6 However , the use of early intravenous X3-blockers in clinical practice is generally low , and this may relate chiefly to concerns about precipitating heart failure in patients with large MI.7 The late 1980s and early 1990s have seen a shift in focus to various antithrombotic strategies ; of these , the value and efficacy of a thrombolytic agent and aspirin have been demonstrated and are widely accepted.8 The benefit of thrombolytic therapy is greater among patients treated early , with only modest benefits among patients treated within 6 - 12 hours after the onset of symptoms.9 Although the benefits of thrombolytic therapy are considered to be mediated by a reduction in infa rct size and improvement in ventricular function , improvements in ejection fraction have not been dramatic.9 Moreover , some of the adverse effects result in permanent morbidity ( e.g. , reinfa rct ion and strokes ) , and costs of some of these agents are substantial . Although the least expensive thrombolytic agent , streptokinase , is affordable in most Western societies , it still represents a large The authors evaluated the antiemetic properties of transdermal scopolamine ( TDS ) in healthy patients undergoing elective cesarean section and receiving epidural morphine for postoperative analgesia . Prior to administration of anesthesia , 203 patients had either TDS or a placebo study patch applied behind one ear . All patients were hydrated with lactated Ringer 's solution iv and given 2.0 % lidocaine with 1:200,000 epinephrine epidurally for surgical anesthesia . Following delivery of the infant , 4 mg of morphine sulphate was injected through the epidural catheter . After the operation patients were evaluated by " blinded " observers at 2 , 4 , 6 , 8 , 10 , 24 , and 48 h for nausea , vomiting , retching , pain relief , itching , and adverse effects . In addition , medications received were noted . No differences were found between the groups in terms of severity or incidence of pain , or requests for analgesic or antipruritic medication . Although there was no difference between the groups in the first 2 h , patients with TDS had significantly less nausea , vomiting , and retching than patients in the placebo group in each time interval between 2 and 10 h. Additionally , the TDS group required less antiemetic medication . There was no difference in the frequency of retching or vomiting between groups . Side effects were minimal and equal in both groups . The authors conclude that TDS results in a decreased incidence of nausea and vomiting in patients who have delivered by cesarean section and received epidural morphine . TDS appears safe for continuous antiemetic administration We evaluated the effectiveness of transdermal scopolamine in patients receiving morphine via patient-controlled intravenous analgesia following intra-abdominal gynecologic surgery . Soon after arrival in the post-anesthesia recovery unit ( time 0 ) , patients were r and omized either to receive or not receive a postauricular transdermal scopolamine patch .  Nausea and vomiting were scored on a 0 - 3 scale at this time and at 2 , 4 , 6 , and 24 hours . Patients were treated with droperidol as deemed necessary by the primary care nurse . Within 2 - 4 hours , transdermal scopolamine patients evidence d less nausea and vomiting and required less droperidol than their counterparts who did not receive transdermal scopolamine . A significant decline in the severity of nausea was noted in the transdermal scopolamine group between 2 - 24 hours ; significant inter-group differences were noted for changes in nausea severity during the 0 - 6-hour and 0 - 24-hour intervals . Transdermal scopolamine patients evidence d a significant ( P<.05 ) decrease in the severity of vomiting during the first 2 hours , significantly different from the increase in the non-transdermal scopolamine patients . After the 4-hour assessment , no transdermal scopolamine patients required droperidol ; nine doses were administered to the patients who were not given transdermal scopolamine ( P<.05 ) . Thus , transdermal scopolamine therapy appears to be an effective means of treating the nausea and vomiting that are encountered after gynecologic surgery We evaluated the effect of transdermal scopolamine on the incidence of  postoperative nausea and vertigo after outpatient ear surgery ( exploratory tympanotomy , mastoidectomy , or endolymphatic sac and oval and round window surgery ) in a double-blind , placebo-controlled study . A transdermal patch containing either scopolamine ( n = 19 )  or placebo  ( n = 20 ) was placed behind the nonsurgical ear 2 h before surgery . Anesthesia was induced with thiopental ( 4 - 6 mg/kg intravenously [ i.v . ] ) , sufentanil ( 0.5 microgram/kg i.v . ) , and vecuronium ( 0.1 mg/kg i.v . ) and maintained with isoflurane ( 0.2%-2 % ) and nitrous oxide ( 70 % ) in oxygen . Patients were observed postoperatively in the recovery room and after discharge for 72 h. There was no significant difference between groups with respect to time in recovery room , time to discharge , incidence of in-house nausea , vomiting , amount of antiemetics required , or postoperative visual analog scale ( VAS ) scores while in the hospital . After discharge , there were lower VAS nausea scores ( by repeat measures analysis , P < 0.05 ) and a lower reported incidence of nausea ( 31 % vs 62 % ; P < 0.05 ) and vertigo ( 6.2 % vs 25 % ; P < 0.05 ) in the active patch group versus the placebo group . There was a higher incidence of dry mouth in the active patch group ( 44 % vs 25 % ) . Seven patients did not complete the study due to failure to keep the patch in place or failure to return the diary from home ; and one patient from the placebo patch group was admitted for uncontrolled nausea and vomiting . The authors concluded that transdermal scopolamine is effective in reducing , but not eliminating , postoperative nausea and vertigo after discharge in outpatient ear surgery The efficacy of transdermal hyoscine in the reduction of nausea , retching and vomiting was compared with placebo during and after stapedo- and tympanoplasty under local anaesthesia in a double-blind , prospect i ve and r and omized study . In the  placebo group ( n = 29 ) , 69 % of the patients were free from emetic symptoms during and 41 % after the operation . The corresponding figures were 93 % ( P < 0.05 ) and 74 % ( P < 0.05 ) in the hyoscine group ( n = 27 ) . The patients in the placebo group needed more droperidol during and after operation ( P < 0.0 
    Output:
    
The timing of application does not alter efficacy .
Incorrect use further limits its efficacy