emergence agitation ( ea ) was described at first by eckenhoff et al in the early 1960s . ea has been described as a dissociated state of consciousness in which the child is inconsolable , irritable , uncooperative , typically thrashing , crying , moaning or incoherent . nowadays , about 4 million children undergo general anesthesia annually and ea has been identified as a significant problem in children at postanesthetic care unit ( pacu ) with an incidence ranging from 10 to 80% . ea as a postanesthetic problem interferes with child s recovery and presents a challenging situation for post - anesthesia care provider in terms of assessment and management . although , several factors have been identified as etiologies of ea , there is no entire description for emergence agitation . many different causes have been suggested , such as rapid awakening in an unfamiliar environment , painful events like surgical wounds , agitation on induction , airway obstructions , environmental disturbances , the duration of anesthesia , hyperthermia , hypothermia , type and site of operation , premedication , inhaled and intravenous anesthetics and the anesthetic technique . although ea is usually self - limited and occurs within the first 30-minutes of recovery in pacu , but it can last up to 2 days and lead to physical damage , disconnection of intravenous catheters , removing of dressing or drainage tube and monitoring devices . on the other hand , controlling the agitated child needs more nursing care and more post - anesthesia care providers . in addition , administration of sedative and analgesics is associated with increased recovery time and delayed pacu discharge . generally , treatment in all cases mentioned above is directed to the correction of causative agents . although , numerous medications have been studied to prevent or reduce ea in children , no special preventive method has been shown to be highly superior . so , this cross - sectional descriptive and analytic study had been undertaken to determine the prevalence of ea , evaluate the risk factors associated with and predictive of it , and describe the outcomes related to ea in children aged 3 to 7 years that underwent general anesthesia for elective surgical procedures . with the approval from the hsr ethics committee of mazandaran university of medical sciences and parental informed consent , this cross - sectional descriptive analytic study was performed on 747 children aged 3 - 7 years with asa physical status i - ii who underwent elective surgery at bou - ali sina hospital in sari , northern iran , between january 2010 and january 2011 . the children enabled to localize the pain , undergoing regional anesthetic technique , recovery time less than 10 minutes , and history of neurological or cardiovascular disorders were excluded . all perioperative routine care was performed under supervision of an anesthesiologist or other physicians and care providers . the data were recorded in a questionnaire including four separated parts ; the first part included the demographic characteristics and the three remaining parts included the behavioral criteria of ea and related factors in pre - anesthetic , during anesthesia , and post- anesthetic period in pacu . at pre - anesthetic period , the child s behavior during separation from his parents and at the time of induction of general anesthesia was graded as calm / cooperating , slightly anxious / fearful , or restless / uncooperative and recorded at presence of an anesthesiologist . the presence or absence of behavior was recorded by yes / no into the questionnaire . perioperative medications , induction and maintenance of anesthetic agents , duration of anesthesia , time of awakening ( namely , time from anesthetic off to time of initial arousal ) were recorded . during pacu , all routine monitoring was performed and all emergence behaviors were observed and recorded by a trained nurse using the reliable and valid pediatric anesthesia emergence delirium ( paed ) scales ( table 1 ) . then the answers of each item were converted into scores and summed together and considered as paed score ; the higher the score , the more agitated child . differentiating ea from the symptoms of postoperative pain was done using flacc behavioral scales with five categories including face , legs , activity , cry and consolability . each of the five categories was scored from 0 - 2 , resulting in a total between 0 and 10 . the results of flacc scale were interpreted as follows : 0 = relaxed and comfortable ; 1 - 3 = mild discomfort ; 4 - 6 = moderate pain ; 7 - 10 = severe pain or discomfort or both . also , all the pharmacologic and non - pharmacologic interventions , undesired side effects and time of discharge from recovery , and physical disturbances were recorded . the patients have been discharged according to pacu discharge criteria with routine practice and at the discretion of the pacu nurse . also , the questionnaire has been shown to have validity in a variety of studies and populations , and reliability of the questionnaire has been approved via a pilot study and cronbach s alpha equal to 0.76 was obtained . pediatric anesthesia emergence delirium ( paed ) scales data were analyzed using spss software 16 and independent sample t - test ,  and binary logistic regression . seven hundred forty- seven children aged 3 - 7 years with asa class i - ii were enrolled over a one year period . one hundred thirty four children ( 17.9% ) had ea . from total , 479 ( 64.1% ) were males and 268 ( 35.9% ) females . the mean age of the patients was 4.891.42 years . from 134 patients with ea , 89 ( 11.9% ) were males and 40 ( 6.0% ) females ( p>0.05 ) . the previous history of surgery and medical diseases were seen in 22 ( 2.9% ) and 8 ( 1.1% ) patients , respectively ( p>0.05 ) . the incidence of ea was higher in operative procedures less than one hour duration ( p=0.022 ) . the mean of awakening time from anesthesia in ea and non - ea patients was 6.202.98 and 4.854.06 , respectively . a significant relationship was observed between mean of awakening time from anesthesia and incidence of ea ( t=3.601 df=742 , p<0.05 ) . the most frequent surgical procedures were ent 315 ( 42.2% ) , abdominal surgery 177 ( 23.7% ) , orthopedic surgery 137 ( 18.3% ) , urologic surgery , 97 ( 13% ) and ophthalmic surgery 24 ( 3.2% ) , respectively . otorhino - laryngological surgical procedures were associated with higher rates of ea ( p<0.05 ) ( table 2 ) . the most sites operated on were the head and neck areas ( 45.6% ) , trunk ( 22.4% ) , extremities ( 18.1% ) and pelvic area ( 13.9% ) . there was significant statistical relationship between the site of operation , and frequency of ea ( p<0.05 ) . this relationship was higher in the head and neck surgery ( p<0.05 ) [ or : 0.34 , ci95% ( 0.23 - 0.50 ) ] temper tantrum was seen in 620 children ( 83.1% ) and 99 ( 13.3% ) of them experienced ea ( p=0.003 ) . from 191 children ( 25.6% ) with history of anxiety , 36 ( 4.8% ) had ea ( p > 0.05 ) . among the 94 ( 12.6% ) of children with different degrees of pain at pacu , 61 ( 8.2% ) had presented ea ( p<0.05 ) . also , the incidence of ea was higher in children with flacc scored 1 - 3 ( p<0.05 ) . there was no relationship between behavioral separation of the patients and ea ( p>0.055 ) , but their induction behavior had significant relationship with ea in pacu ( p<0.005 ) ( table 3 ) . as shown in the table , isoflurane and atracurium had the highest relationship with incidence of ea ( p<0.05 ) . the logistic regression analysis of the factors that had a significant effect on the incidence of ea , revealed that two factors ; pain and children s induction behavior were associated with the increased incidence of ea from anesthesia ( table 5 ) . the relationship between type of surgical operation and presence of ea relationship between children s behavior in separation and induction times and ea postoperative emergence agitation , also known as emergence delirium in international literature is a well - known clinical phenomenon with an incidence ranging 10 - 80% . recognizing the risk factors for ea is very important to minimize the contributing factors and managing ea appropriately . we investigated multiple risk factors associated with ea such as the patient and surgical related factors , as well as anesthesia related risk factors such as rapid emergence and type of anesthetics . the incidence of ea in our study was 17.9% based on paed score of 12 . the present study showed that the children aged 4 - 6 years had a higher incidence of ea compared to children aged 7 years . it may be due to less psychological and physiological immaturity of young - aged children compared to school - aged children being less able to cope with rapid awakening in an unknown environment . similarly , we found thatchildren with agitation during the induction of anesthesia had a higher risk of developing ea . some early reports have suggested that otorhinolaryngological surgical procedures appeared to exhibit an increased incidence of agitation . when eckenhoff et al first described the ea in 1961 , attributed the increased incidence among otolaryngologic procedures to the  sense of suffocation  . after that , in 2003 , voepel - lewis in a prospective study has shown that the otolaryngologic procedures are independent risk factors for ea . in our study , ea was associated with ent , abdominal and orthopedic surgical procedures . also , surgical procedures performed on the head and neck was associated with higher risk of ea . so , not only the type of surgical procedure , but also the surgical site may play a role in the incidence of ea . the association between anesthetic agents and presence of emergence agitation factors predictive of emergence agitation ( step 1a ) postoperative pain appears to be an aggravating factor , and its behavioral manifestations may be confused with emergence agitation diagnosis . several studies have discussed that pain during impaired consciousness leads to severe ea in some children . however , a clear relationship has not been established . in differentiating postoperative pain from ea , we used both flacc and paed tools to facilitate the decision making in involved children . we found that although ea decreased after adequate pain control , it was not eliminated completely . the authors believe that flacc may be less reliable in children who experienced ea than in those who experienced pain only . nevertheless , clinical experience and the review of the literature have suggested that when caring for children in pacu , it may not be necessary to differentiate ea from pain , especially because the treatment is similar for both of them . some authors have observed a reduction in preoperative anxiety and easier to separate children from parents . also , they observed a reduction in agitation when midazolam was used as premedication followed by sevoflurane as anesthetic . however , some authors have reported that emergence time was prolonged when midazolam was used . among the inhaled anesthetic agents used in this study , isoflurane was associated with 9.8% of ea compared with sevoflurane ( 2.5% ) and halothane ( 0.7% ) . eeg changes caused by the effects of isoflurane and sevoflurane on the central nervous system have also been suggested as a possible causative agent of agitation . propofol has been demonstrated to be effective as an adjunct to sevoflurane inhalational general anesthesia in reducing the incidence of ea . we have also found no relationship between propofol and increased ea . among the intravenous anesthetics used in the present study conversely , dalens et al showed that the administration of 0.25 mg / kg of ketamine at the end of the mri in children reduced agitation with no delay in discharge . sufentanil is a potent opioid which is usually used as a standard treatment of ea because it relieves pain without influencing pacu length of stay . we found a positive association between sufentanil used as opioid and the incidence of ea . the authors suggest that the co - administration of sufentanil and isoflurane may cause this controversy . there are controversies about the effect of duration of anesthesia on the incidence of ea . the higher incidence of ea has been observed in short - duration surgery as well as in the long - duration . it was suggested that ea may be attributed to shorter - duration surgeries due to rapid washout of anesthetics from the body , causing rapid emergence before analgesics have enough time to act and reach their peak effect . atracurium was another anesthetic agent that we detected related to the incidence of ea in our patients . although , laudanosine as main metabolite of atracurium can play a role in ea because of its cns excitation effect . the authors suggest that it can not be the causative phenomenon , because laudanosine can be activated in neuromuscular junction at its non - clinical high concentration . on the other hand , the short duration of most surgical procedures this study has identified that multiple independent risk factors such as post - operative pain , short time awaking , anesthetic drugs including sufentanil , isoflurane , atracurium , and also ent surgeries , as well as site of operation were the risk factors of ea in children aged 3 - 7 years . although ea in this sample was relatively of short duration , pharmacologic intervention was required in 6.7% of cases , and ea was associated with a prolonged pacu stay without significant adverse effect only in 2% of all cases . alam sahbpour , sa mousavi : critical revision of manuscript s. khani and s. shahmohammadi : concept / design , data analysis and manuscript preparation all authors approved of the final version of the article .