managing the comfort of children in the pediatric intensive care unit ( picu ) is one of the most difficult challenges facing pediatric staff . these critically ill children are placed in an unfamiliar and unpredictable environment , where visual and auditory stimuli are excessive , painful stimuli are frequent , and sleep disturbances are common ( 1 , 2 ) . sedation is an essential tool in maintaining an optimal level of comfort and safety for critically ill patients ( 3 ) . excessive sedation , however , can lead to prolonged mechanical ventilation , ventilator - associated pneumonia or lung injury , or neuromuscular disorders . by contrast , too little sedation can lead to interference with effective mechanical ventilation , myocardial and cerebral ischemia , and potentially dangerous outcomes such as self - extubation or removal of other mechanical devices ( 4 ) . although clinical tools are available to assess and monitor the degree of sedation in individual patients ( 5 ) , most of them have limitations in children . however , the comfort scale has been validated in critically ill children ( 6 ) . in adults , there is increasing evidence that protocol - directed sedation of intubated patients can reduce the duration of mechanical ventilation , the length of stay in the intensive care unit ( icu ) and hospital , and tracheostomy rates , and can enhance the quality of sedation with reduced drug costs ( 7 - 9 ) . however , few studies have evaluated the effects of sedation practices on clinical outcomes in children . we therefore sought to identify whether protocol - directed sedation with the comfort scale in critically ill children could affect clinical outcomes , including duration of mechanical ventilation , length of stay in the icu , total amount and duration of sedatives , and withdrawal symptoms . the study was conducted at the picu ( 22 beds ) of asan medical center ( amc ) , seoul , korea . patients were eligible if they were intubated , received mechanical ventilation , and required sedation through continuous intravenous infusion for longer than 48 hr . patients who were admitted to the picu after surgery , resuscitated from cardiac arrest , transferred from an outside institution where sedatives had already been administrated , or had abnormal neurological deficits were excluded . 1 ) was developed prior to this study , and picu physicians were encouraged to adhere to this protocol during the study period . during the 12-month period ( july 2003-june 2004 ) , one clinical pharmacist evaluated the level of sedation twice daily in each patient using the comfort scale . the pharmacist then discussed these results with an attending physician , who adjusted the infusion rates of sedatives to attain an optimal comfort score , between 17 and 26 points . data were collected prospectively for the study period ( intervention group ) and were compared with retrospective empiric therapy results during a 12-month period ( july 2002-june 2003 ) prior to the study ( control group ) . the control group consisted of patients admitted to the picu who satisfied the study inclusion criteria . baseline demographic data , prism iii score , and reason for admission were recorded for all patients . clinical outcome variables , including duration of mechanical ventilation , length of stay in the picu , total dose of sedatives , and occurrence of withdrawal symptoms were compared between the two groups . continuous variables were analyzed using the mann - whitney rank sum test and presented as median values ( with 25th and 75th percentiles ) . discrete variables were analyzed using chi - square analysis with fisher 's exact test or pearson 's chi - square test , as appropriate . a p value less than < 0.05 was considered statistically significant , and all tests were based on two - sided hypothesis testing . a total of 53 patients were included in the study , 26 in the intervention group and 27 in the control group . five patients in the intervention group and seven in the control group were later excluded because their endotracheal tubes had been removed or they died within the first 48 hr . thus , 21 patients in the intervention group and 20 patients in the control group were included in the analysis . demographic characteristics , prism iii scores and diagnosis on icu admission were similar in the two groups . the type of continuously used sedatives did not differ significantly between the two groups ( table 1 ) . neuromuscular blocking agents were infused continuously into nine patients in the intervention group and eight in the control group ( p=0.85 ) . the use of protocol - directed sedation with the comfort scale in the intervention group was associated with significant decreases , compared with the control group , in the mean duration of mechanical ventilation ( 12.5 vs. 11.0 days , p=0.04 ) and in the median length of stay in the picu ( 15.0 vs. 19.5 days , p=0.04 ) ( table 2 ) . the duration of sedation also tended to be lower in the intervention group than in the control group ( 8.0 days vs. 11.5 days , p=0.053 ) ( table 2 ) . the overall development of withdrawal symptoms was significantly lower in the intervention than in the control group ( 1 vs. 7 patients , p=0.02 ) . mild withdrawal symptoms , mainly presenting as loose stools and vomiting , was seen in one patient in the intervention group and five in the control group ; whereas moderate withdrawal symptoms , presenting as tremors and abnormal sleep patterns , were observed only in two control group patients ( table 2 ) . the total dose and maximum rate of continuous fentanyl infusion and the maximum rate of continuous midazolam infusion were significantly lower in the intervention group than in the control group ( table 3 ) . except for ketamine , the frequencies of intermittent doses of sedatives and neuromuscular blocking drugs were also significantly lower in the intervention group than in the control group ( table 3 ) . a total of 53 patients were included in the study , 26 in the intervention group and 27 in the control group . five patients in the intervention group and seven in the control group were later excluded because their endotracheal tubes had been removed or they died within the first 48 hr . thus , 21 patients in the intervention group and 20 patients in the control group were included in the analysis . demographic characteristics , prism iii scores and diagnosis on icu admission were similar in the two groups . the type of continuously used sedatives did not differ significantly between the two groups ( table 1 ) . neuromuscular blocking agents were infused continuously into nine patients in the intervention group and eight in the control group ( p=0.85 ) . the use of protocol - directed sedation with the comfort scale in the intervention group was associated with significant decreases , compared with the control group , in the mean duration of mechanical ventilation ( 12.5 vs. 11.0 days , p=0.04 ) and in the median length of stay in the picu ( 15.0 vs. 19.5 days , p=0.04 ) ( table 2 ) . the duration of sedation also tended to be lower in the intervention group than in the control group ( 8.0 days vs. 11.5 days , p=0.053 ) ( table 2 ) . the overall development of withdrawal symptoms was significantly lower in the intervention than in the control group ( 1 vs. 7 patients , p=0.02 ) . mild withdrawal symptoms , mainly presenting as loose stools and vomiting , was seen in one patient in the intervention group and five in the control group ; whereas moderate withdrawal symptoms , presenting as tremors and abnormal sleep patterns , were observed only in two control group patients ( table 2 ) . the total dose and maximum rate of continuous fentanyl infusion and the maximum rate of continuous midazolam infusion were significantly lower in the intervention group than in the control group ( table 3 ) . except for ketamine , the frequencies of intermittent doses of sedatives and neuromuscular blocking drugs were also significantly lower in the intervention group than in the control group ( table 3 ) . using a sedation protocol has been shown to be effective in adjusting sedation at the ' agitated ' end of the range , whereas sedation scoring systems have been found effective in adjusting sedation regimens at the opposite , or ' over - sedated ' , end of the range ( 10 ) . to navigate between agitation and over - sedation , we integrated the comfort scale with the picu sedation protocol at amc . in this study , we investigated and documented the effect of the systematic use of a sedation protocol together with the comfort scale in critically ill children requiring mechanical ventilation . we found that this combination produced better outcomes than the subjective judgment of a physician alone . the duration of mechanical ventilation and the length of stay in the icu were significantly reduced in the intervention group compared with the control group . these findings are consistent with the results of previous studies in adults , which demonstrated relationships between sedation practices and the duration of mechanical ventilation ( 11 - 16 ) . our sedation protocol was developed for patients requiring mechanical ventilation . to determine optimal sedation level goals , physicians were required to evaluate each patient 's causes of restlessness and whether analgesics , sedatives or both were required . in addition , a pharmacist and a nursing team were employed to support these judgments . our protocol provided guidelines for choices of analgesics and/or sedatives , daily reassessment , and dose adjustments . to our knowledge , no previous studies have addressed the clinical effects of a sedation protocol plus a sedation scoring system in children . our study results suggest that sedation protocols together with the comfort scale can be safely implemented to improve outcomes in critically ill children . we chose to use the comfort scale as a sedation scoring system , because it has been demonstrated to be reliable and has been validated as a descriptor of behavioral and physiologic distress in critically ill children ( 17 - 20 ) . in addition , the comfort scale can measure not only the level of consciousness but other parameters , including face grimacing , muscle tone , physiological values and the level of agitation , all of which are considered possible reflectors of tolerability to the picu environment . the target range of the comfort score corresponding to optimal sedation has been found to be between 17 and 26 points ( 21 ) . we therefore used this range as our target goal , and we regulated the infusion rate of sedatives for each patient using the comfort score and the sedation protocol . maintenance of the optimal level of sedation would therefore reduce the amount of times patients were over - sedated or agitated , thus reducing the amount and frequency of sedatives used . we found that the doses of continuously infused sedatives and their maximal infusion rates were lower in the intervention group , as was the frequency of prn or intermittently used sedatives . critically ill children who have required long - term sedation for mechanical ventilation often experience withdrawal syndromes after the termination of sedation , characterized by agitation , anxiety , muscle twitching , sweating , and tremors ( 22 ) . previous studies of protocol - based sedation , however , have not evaluated withdrawal symptoms in these children ( 3 , 11 , 12 , 23 , 24 ) . abstinence syndrome is commonly associated with opiates and benzodiazepines , usually occurring between 5 and 10 days after drug commencement ( 22 ) . we thus classified patients receiving more than 5 days of sedative treatment into a risk group for withdrawal symptoms . patients in the risk group who required reduced doses of sedatives had their infusion rates reduced by 10 - 25% of the original dose at an interval of 12 - 24 hr , with withdrawal symptoms monitored using a modified finnegan score ( 25 ) . we found that both the incidence and severity of withdrawal symptoms were reduced in our intervention group . since it was not a randomized , controlled trial , and it used a historical control group , methodologic weaknesses were present , and it was difficult to quantify the effects of bias , including those associated with improved general care between the sampling periods of the two groups . however , there were no differences in main strategies on ventilator care and attending staff , and we believe the quality of general care was also similar . in addition , our study evaluated small numbers of patients in each group . inclusion of larger numbers of patients would require a longer study period , but that may have led to more errors inherent in using historical controls . furthermore , we did not evaluate the impact of sedation protocol on other outcomes , such as the occurrence of unplanned extubation and ventilator - associated pneumonia , and on treatment costs . in conclusion , we found that the picu sedation protocol of asan medical center , together with the comfort scale , may be a safe and practical approach to treating pediatric patients receiving mechanical ventilation . this protocol decreased the duration of mechanical ventilation , the length of stay in the picu , total dose of sedatives , and the incidence of withdrawal symptoms .
sedation is often necessary to optimize care for critically ill children requiring mechanical ventilation . 
 if too light or too deep , however , sedation can cause significant adverse reactions , making it important to assess the degree of sedation and maintain its optimal level . 
 we evaluated the efficacy of the comfort scale in assessing optimal sedation in critically ill children requiring mechanical ventilation . 
 we compared 12 month data in 21 patients ( intervention group ) , for whom we used the pediatric intensive care unit ( picu ) sedation protocol of asan medical center ( seoul , korea ) and the comfort scale to maintain optimal sedation , with the data in 20 patients ( control group ) assessed before using the sedation protocol and the comport scale . 
 compared with the control group , the intervention group showed significant decreases in the total usage of sedatives and analgesics , the duration of mechanical ventilation ( 11.0 days vs. 12.5 days ) and picu stay ( 15.0 days vs. 19.5 days ) , and the development of withdrawal symptoms ( 1 case vs. 7 cases ) . 
 the total duration of sedation ( 8.0 days vs. 11.5 days ) also tended to decrease . 
 these findings suggest that application of protocol - based sedation with the comport scale may benefit children requiring mechanical ventilation .