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  Background & Objectives: Pain is one of the most common problems for which human have always been looking for efficient treatment. Several different factors may cause pain, but one of the most widespread reason is the application of some treatments and nursing measures such as intramuscular injection. The present study was designed to compare between the intensity of pain due to intramuscular injection by two different methods: Z- track and Air lock method.

  Methods: In this semi-experimental study, 60 volunteer female nursing students were included. The subject was injected with one milliliter of sterilized water two times within 24 hours: the first injection by Z method and the second one by the Air lock method. The intensity of pain was measured two times by a scale graded from zero to ten. The results were compared by using descriptive statistics and independent t-test by SPSS 12 software.

  Results: Our findings showed that the mean of pain intensity in Z method was 1.80 ± 1.90, and raised to 3.13 ± 2.33 in Air lock method. Moreover, the intensity of pain in these two different methods had significant difference (p<0.01).

  Conclusion: These results indicated that the pain caused by Z method is less than the pain felt through Air lock method. With respecting to these results the Z method is proposed as preferred method for intramuscular injections.

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Background & objectives: In many medical studies, the response variable is measured repeatedly over time to evaluate the treatment effect that is known as longitudinal study. The analysis method for this type of data is repeated measures ANOVA that uses only one correlation structure and the results are not valid with inappropriate correlation structure. To avoid this problem, a convenient alternative is mixed models. So, the aim of this study was to compare of mixed and repeated measurement models for examination of the Entonox effect on the labor pain.

Methods: This experimental study was designed to compare the effect of Entonox and oxygen inhalation on pain relief between two groups. Data were analyzed using repeated measurement and mixed models with different correlation structures. Selection and comparison of proper correlation structures performed using Akaike information criterion, Bayesian information criterion and restricted log-likelihood. Data were analyzed using SPSS-22.

Results: Results of our study showed that all variables containing analgesia methods, labor duration of the first and second stages, and time were significant in these tests. In mixed model, heterogeneous first-order autoregressive, first-order autoregressive, heterogeneous Toeplitz and unstructured correlation structures were recognized as the best structures. Also, all variables were significant in these structures. Unstructured variance covariance matrix was recognized as the worst structure and labor duration of the first and second stages was not significant in this structure.

Conclusions: This study showed that the Entonox inhalation has a significant effect on pain relief in primiparous and it is confirmed by all of the models.

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Background & objectives: The aim of this study was to evaluate the effects of preventive administration of ketamine, fentanyl and paracetamol on pain intensity and hemodynamic parameters after deep vitrectomy.
Methods: In this clinical trial, 80 candidates of deep vitrectomy surgery were randomly assigned into 4 groups (1-4) and received 0.5 mg / kg ketamine, 2 μg / kg fentanyl, 10 mg/kg of paracetamol and equivolume of normal saline respectively intravenous infusion during the last 15 minutes of surgery. Pain intensity and hemodynamic parameters were recorded and analyzed.
Results: Pain intensity was significantly higher in placebo group during the first 4 hours after operation (p<0.01), but no significant differences were observed between the study groups at 8 and 24 hours after operation in this regard. There were no significant differences between the three intervention groups in terms of pain intensity during the study. Also there were no significant differences between the 4 study groups regarding to hemodynamic parameters.
Conclusion: The use of each of the three intervention drugs significantly reduced the pain intensity compared to the control group without any hemodynamic derangement.