Predictors for difficult cecal insertion in colonoscopy: The impact of obesity indices

AIM To identify the factors influencing cecal insertion time(CIT) and to evaluate the effect of obesity indices on CIT. METHODS We retrospectively reviewed the data for participants who received both colonoscopy and abdominal computed tomography(CT) from February 2008 to May 2008 as part of a comprehensive health screening program. Age, gender, obesity indices [body mass index(BMI), waist-to-hip circumference ratio(WHR), waist circumference(WC), visceral adipose tissue(VAT)volume and subcutaneous adipose tissue(SAT) volume on abdominal CT], history of prior abdominal surgery, constipation, experience of the colonoscopist, quality of bowel preparation, diverticulosis and time required to reach the cecum were analyzed. CIT was categorized as longer than 10 min(prolonged CIT) and shorter than or equal to 10 min, and then the factors that required a CIT longer than 10 min were examined.RESULTS A total of 1678 participants were enrolled. The mean age was 50.42 ± 9.931 years and 60.3% were men. The mean BMI, WHR, WC, VAT volume and SAT volume were 23.92 ± 2.964 kg/m2, 0.90 ± 0.076, 86.95 ± 8.030 cm, 905.29 ± 475.220 cm3 and 1707.72 ± 576.550 cm3, respectively. The number of patients who underwent abdominal surgery was 268(16.0%). Colonoscopy was performed by an attending physician alone in 61.9% of cases and with the involvement of a fellow in 38.1% of cases. The median CIT was 7 min(range 2-56 min, IQR 5-10 min), and mean CIT was 8.58 ± 5.291 min. Being female, BMI, VAT volume and involvement of fellow were significantly associated with a prolonged CIT in univariable analysis. In multivariable analysis, being female(OR = 1.29, P = 0.047), lower BMI(< 23 kg/m2)(OR = 1.62, P = 0.004) or higher BMI(≥ 25 kg/m2)(OR = 1.80, P < 0.001), low VAT volume(< 500 cm3)(OR = 1.50, P = 0.013) and fellow involvement(OR = 1.73, P < 0.001) were significant predictors of prolonged CIT. In subgroup analyses for gender, lower BMI or higher BMI and fellow involvement were predictors for prolonged CIT in both genders. However, low VAT volume was associated with prolonged CIT in only women(OR = 1.54, P = 0.034).CONCLUSION Being female, having a lower or higher BMI than the normal range, a low VAT volume, and fellow involvement were predictors of a longer CIT.

Effect of music on colonoscopy performance: A propensity scorematched analysis

BACKGROUND Music has been used to reduce stress and improve task performance during medical therapy.AIM To assess the effects of music on colonoscopy performance outcomes.METHODS We retrospectively reviewed patients who underwent colonoscopy performed by four endoscopists with popular music.Colonoscopy performance outcomes,such as insertion time,adenoma detection rate(ADR),and polyp detection rate(PDR),were compared between the music and non-music groups.To reduce selection bias,propensity score matching was used.RESULTS After one-to-one propensity score matching,169 colonoscopies were selected from each group.No significant differences in insertion time(4.97 vs 5.17 min,P=0.795)and ADR(39.1%vs 46.2%,P=0.226)were found between the two groups.Subgroup analysis showed that the insertion time(3.6 vs 3.8 min,P=0.852)and ADR(51.1%vs 44.7%,P=0.488)did not significantly differ between the two groups in experts.However,in trainees,PDR(46.9%vs 66.7%,P=0.016)and ADR(25.9%vs 47.6%,P=0.006)were significantly lower in the music than in the nonmusic group.CONCLUSION The current study found that listening to music during colonoscopy did not affect procedure performance.Moreover,it suggested that music may distract trainees from appropriately detecting adenomas and polyps.

Measurement of insertion loss for underwater acoustic passive materials with the time reversal technique

A method using the time reversal（TR） technique to measure the insertion loss（IL） of passive materials is presented.Firstly the received signals are focused according to the TR theory when there is not a sample between the source and the received array.Then,the sample is placed near the received array and the TR processing is again employed to realize the focus of the received signal.Finally,the IL of the sample is evaluated from these focusing signals.Because the TR processing can focus the energy in spatial domain and time domain,the method can be used to measure acoustic properties of passive materials in a waveguide tank with reflections induced by boundaries or with low source frequencies.Two samples with the same size of 1.1 m×1.0 m×5 mm are tested in the waveguide tank.The method is demonstrated by the comparison of the theoretical and the experimental results in the measured frequency range of 1-20 kHz.