Cumulative sum analysis score and phacoemulsification competency learning curve

AIM： To use the cumulative sum analysis score（CUSUM） to construct objectively the learning curve of phacoemulsification competency.METHODS： Three second-year residents and an experienced consultant were monitored for a series of 70 phacoemulsification cases each and had their series analysed by CUSUM regarding posterior capsule rupture（PCR） and best-corrected visual acuity. The acceptable rate for PCR was 〈5%（lower limit h） and the unacceptable rate was 〉10%（upper limit h）. The acceptable rate for bestcorrected visual acuity worse than 20/40 was 〈10%（lower limit h） and the unacceptable rate was 〉20%（upper limit h）. The area between lower limit h and upper limit h is called the decision interval. RESULTS： There was no statistically significant difference in the mean age, sex or cataract grades between groups. The first trainee achieved PCR CUSUM competency at his 22 nd case. His best-corrected visual acuity CUSUM was in the decision interval from his third case and stayed there until the end, never reaching competency. The second trainee achieved PCR CUSUM competency at his 39^ th case. He could reach best-corrected visual acuity CUSUM competency at his 22 ^nd case. The third trainee achieved PCR CUSUM competency at his 41 st case. He reached bestcorrected visual acuity CUSUM competency at his 14 ^th case.CONCLUSION： The learning curve of competency in phacoemulsification is constructed by CUSUM and in average took 38 cases for each trainee to achieve it.

MECHANISM OF ANALGESIC EFFECTS OF PROPOFOL ON INCISIONAL PAIN:A RAT MODEL STUDY

Objective To clarify the role of propofol in controlling incisional pain and its potential effects on the spinal opioid receptor expression. Methods A postoperative model of nociception was established in male Sprague-Dawley rats weighing 200 -250 g. A total of 96 rats were randomly divided into 8 groups. All drugs were administered intravenously either 5 rain pre-operation or 5 rain post-operation. The analgesic effects of systemic propofol were demonstrated by the measurement of a cumulative pain score （ CPS ）. After that, the lumbar enlargement of the spinal cord was removed to evaluate the mRNA level of the μ-opioid receptor （ MOR ） and δ-opioid receptor （ DOR） by RT-PCR. Results CPS and DOR mRNA expressions significantly increased after the operation. Both propofol post-treatment and propofol pre-treatment groups showed significant suppression of the increased CPS and the expression of DOR mRNA evoked by pain stimulation. Interestingly, propofol pre-treatment had a more pronounced effect in decreasing CPS and the expression of DOR mRNA. Furthermore, these observations were dose-dependent. MOR mRNA expression significantly increased after operation in all animals and propofol treatment had no impact on it. Conclusion Based on these findings, we suggest that propofol can serve as a valuable adjunct in acute postoperative pain management. Systemic propofol induces an analgesic effect on acute incisional pain in a dose-dependant manner, and this effect is mediated in the spinal cord and may be associated with the spinal DOR.