The present study was a randomized single-blind clinical trial performed among intubated patients with loss of consciousness. The patients were on ventilator support and hospitalized in the ICU of Khatam al-Anbiya Hospital in Zahedan. Sample size was determined in accordance with the study of Shahriari et al. (
27) and based on the
Equation 1.

Equation 1.
= 1.12, = 1.84, S1 = 1.35, S2 = 0.94, Z 1-β = 0.85, Z 1-α/2 = 1.96
Sample size was estimated at 42 for each group. To increase the confidence interval and considering possible sample attrition, the number of patients in each group was set at 45; thus, a total of 90 patients were studied. After obtaining a written consent form from the patients’ legal guardians, the participants were chosen through convenience sampling. Using permuted block randomization, the subjects were assigned into two groups of pain management algorithm and control. Since both groups were necessary for carrying out this research, the patients were enrolled according to six schemes of four-member blocks, in which As and Bs were respectively assigned to the pain management algorithm and control groups (for example, AABB, ABAB, BBAA, etc.); each block consisted of two participants from each group. The order of the blocks was determined randomly by means of a random number generator, and patients were entered into the intervention or control groups according to the blocks. Single-blindness of this research was due to the fact that the pain assessor was not aware of the group allocations.
The most important inclusion criteria were: 18 to 65 years of age, no history of plegia, no history of chronic pain such as migraine or backache, no history of neuromuscular or sensorimotor disorders, no history of paralytic medications consumption, level of consciousness between 5 to 8 according to Glasgow Coma Scale, and initiation of painkiller infusion. On the other hand, the most notable exclusion criteria were regaining full consciousness and tracheal extubation at any point throughout the study, transfer to surgery room for surgical operations, consumption of muscle relaxant medications at any point during the research, patient’s transfer to any other ward or any other hospital, patient’s demise, and impossibility of changing painkiller dosage for any particular reason according to doctors’ prescriptions (as one of the phases of algorithm implementation).
The instruments used in this study included a demographic checklist (consisting of personal information and particularities of the disease) and the Behavioral Pain Scale (BPS). BPS is used as a pain assessment tool in patients who are on mechanical respiratory support and are unable to describe their pain level. This instrument was designed by Payen et al. (
28) and consists of three parts, including facial expression, upper limb movement, and compliance with mechanical ventilation, each one being scored between 1 to 4. Higher scores indicate a higher level of pain and agitation. The total score ranges between a minimum of 3 (minimum pain level) and a maximum of 12 (maximum pain level). The reliability of this instrument has been confirmed by studies conducted in Iran and abroad (
28-
32). In addition, its internal consistency was reported 0.94 according to Cronbach’s alpha coefficient. Also, in the present study, the reliability of this tool was established using Cronbach’s alpha coefficient (0.91) and intraclass correlation coefficient (0.89) (
28).
In order to conduct this research, after obtaining approval of the university’s Ethics Committee (registered with the code IR.Zaums.REC.1396.357) and permission of the hospital authorities, the research team began data collection. After explaining the purpose of the research and the intervention procedure to families of the qualified patients, the authors asked them to submit a written consent on behalf of their patient to participate in the study.
The algorithm used here is an inclusive approach to the use of pain assessment and pain evaluation tools. It plays a significant role in helping ICU nurses and doctors in managing patient’s pain based on the findings of the evaluation. This algorithm involves repeated assessments of pain and adjustment of the prescribed painkiller dosage in accordance with the latest assessment of pain intensity (
5). In the intervention group, pain management algorithm was implemented in three work shifts throughout an entire day. The researcher was responsible for implementing the algorithm and explaining it to the nurses of the ward as well. The researcher applied the algorithm in three working shifts: In the morning between 8 to 10 a.m., in the evening between 3 to 5 p.m. and at night between 10 p.m. and midnight. This algorithm incorporates two types of pain assessment instruments for both patients who are capable of communication and those with loss of consciousness who are on ventilation support and incapable of verbal communication. Since the present study addresses patients with loss of consciousness, BPS was chosen for this purpose according to the algorithm.
Based on pain management algorithm and by using BPS, the researcher measured and recorded the patients’ pain level twice during every working shift, once before implementing the algorithm and another time after that. In the event that the initial BPS score was between 3 and 5, pain relief measures including the infusion of painkillers would be reduced after consulting the physician in charge. In other words, the patient’s intake of sedatives would be lowered as required. Based on the algorithm, 15 minutes after intravenous sedative infusion, pain was reassessed and the resulting score was recorded in certain sheets.
In case the initial level of pain intensity measured by BPS exceeded 5, pain relief measures would increase after informing the anesthesiologist and consulting with him/her. As in the previous situation, 15 minutes after the intravenous infusion, pain intensity was reevaluated and the result was recorded in the forms. It should be noted that in all cases an anesthesiologist was consulted prior to increasing or decreasing the patient’s medication dosage. Pain relief measures varied according to the doctor’s orders, and they included painkillers such as midazolam, fentanyl, and morphine. The medications were infused separately or in pairs. Participants of the control group only received the routine care and pain control measures provided by the ward. Pain assessment was carried out in the three shifts, similar to the intervention group.
After data collection, SPSS 15 was employed for analyzing them. Descriptive statistical tests (including frequency distribution table, mean, and standard deviation) were used to describe the data. Firstly, using Shapiro Wilk normality test, the normality of data was evaluated. Since it was proven normal, the mean values of quantitative variables in the intervention and the control groups were compared using the independent t-test. Besides, in order to examine the mean values of quantitative variables before and after the intervention separately in the two groups, paired t-test was used. Chi-square test was employed to analyze qualitative variables in the two groups. Finally, P value less than 0.05 was considered significant.