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2015; Lippincott Williams & Wilkins; Volume: 41; Issue: 8 Linguagem: Inglês

10.1016/j.jcrs.2015.07.031

1873-4502

Roberto Pinto Coelho, Ricardo Hélio Biaggi, Rodrigo Jorge, Maria de Lourdes Veronese Rodrigues, André Messias,

Dental Anxiety and Anesthesia Techniques

We are pleased that Drs. Lim and Tan appreciated our work and made their comments, which surely improve on our research. Although we reported only the results from the parametric test in our article, we had also compared our sample using a nonparametric test. The results are similar: P = .1926, Wilcoxon signed-rank test. In fact, the lower number of patients with higher pain scores with cold solution (8/25) might be an indicator of the higher probability of lower pain scores if the infusion solution were colder. On the other hand, the small, and not statistically significant, mean difference in pain scores between cold solution versus room-temperature solution also indicates that this might be clinically irrelevant. We made this observation in our discussion (page 722). Also, we made clear to the reader that a larger number of patients reported a lower pain score with cryoanalgesia. We did not monitor infusion temperature during surgery. Other authors consider it very unlikely that room temperature could markedly change the solution temperature during the 15 minutes of surgery. Moreover, for each surgery, 500 mL of a balanced salt solution was taken from a 4°C refrigerator in the operating room. Considering a room temperature of 23°C for 15 minutes, we would expect only a small increase in temperature. Sample-size estimation was based on the standard deviation found for pain sensation scores during cataract surgery in a similar environment,1 meaning that all these variables were automatically taken into account. The inclusion of a larger number of patients could have led to statistical significance but could have detected smaller differences. The minimum difference in the pain score that could have been detected with our sample was 7.1, which we considered reasonable. In addition, the highest difference between pain scores was approximately 30, either higher for cold solution or higher for room-temperature solution (Figure 1, page 722), indicating that the cold temperature increased the discomfort in some patients to a degree similar that it decreased pain in other patients. We appreciate that Drs. Lim and Tan mention the use of intracameral lidocaine to reduce pain during phacoemulsification. We agree that this has been used as an alternative for topical anesthesia alone; however, it has drawbacks, such as the potential pain caused by the lidocaine infusion and safety issues regarding toxicity and infection. In summary, as Drs. Lim and Tan commented, our aim is to reduce discomfort during phacoemulsification, which in our opinion is best achieved using topical anesthesia, which has no significant benefit in practice if cold infusion is used to induce cryoanalgesia.