Multiple comparisons tests (MCTs) are performed several times on the mean of experimental conditions. When the null hypothesis is rejected in a validation, MCTs are performed when certain experimental conditions have a statistically significant mean difference or there is a specific aspect between the group means. A problem occurs if the error rate increases while multiple hypothesis tests are performed simultaneously. Consequently, in an MCT, it is necessary to control the error rate to an appropriate level. In this paper, we discuss how to test multiple hypotheses simultaneously while limiting type I error rate, which is caused by α inflation. To choose the appropriate test, we must maintain the balance between statistical power and type I error rate. If the test is too conservative, a type I error is not likely to occur. However, concurrently, the test may have insufficient power resulted in increased probability of type II error occurrence. Most researchers may hope to find the best way of adjusting the type I error rate to discriminate the real differences between observed data without wasting too much statistical power. It is expected that this paper will help researchers understand the differences between MCTs and apply them appropriately.
Analysis of Variance ; Hope ; Inflation, Economic

Pressure damage to respiratory mucosa from overinflation of bronchial cuffs has been implicated as a cause of bronchial rupture, a rare but devastating complication of double-lumen endobronchial tubes (DLTs). In vivo, we evaluated the pressure/volume characteristics of the bronchial cuffs by left main bronchus diameter and DLT size. Thirty patients were divided into three groups : in group 1, 35 Fr DLT was used and left main broncus diameter (LMBD) was less than 12 mm; in group 2, 37 Fr DLT and LMBD less than 12 mm ; in group 3, 37 Fr DLT and LMBD larger than 12 mm. The bronchial cuff volume needed to seal left main bronchus(cuff sealing volume) and bronchial cuff pressure to 2.5 ml of cuff volume at 0.5 ml increments were measured . The results were as follows. 1) The mean+SE cuff sealing volume were 0.3+/-0.1 ml, 0.4+/-0.1 ml and 1.0+/-0.2 ml in group 1, 2 and 3 respectively. 2) The mean+ SE bronchial cuff pressure at 0.5, 1, 1.5 and 2 ml of cuff volume were 27.5+/-5.0, 64.0+/-10.2, 105.4+/-15.5, 124.1+/-16.7 mmHg in group 1, 31.5+/-3.7, 74.1+/-6.2, 126.0+/-11.8, 175.3+/-14.6 mmHg in group 2 and 10.9+/-2.4, 23.8+/-3.4, 50.5+/-5.4, 89.2+/-7.5 mmHg in group 3 respectively. We concluded that initial cuff inflation volume of 0.5 ml in group 1 and 2, 1ml in group 3 is appropriate.
Bronchi* ; Humans ; Inflation, Economic ; Respiratory Mucosa ; Rupture

BACKGROUND: Core temperature changes during tourniquet inflation and deflation have been reported. The aim of this study is to investigate the extent of core temperature changes during inflation and deflation, depending on tourniquet time. METHODS: Esophageal temperature in sixty patients who undergoing knee arthroscopy with tourniquet longer than 1 h (group L, n = 30) and less than 1 h (group S, n = 30) were measured before inflation, 30 and 60 min after inflation, just before deflation, and 1 min interval for 10 min after deflation. RESULTS: Tourniquet time in L and S group was 109 +/- 20 min and 46 +/- 10.7 min, respectively. Compared to baseline value of 35.7 +/- 0.07 degrees C, significant increase of 0.14 +/- 0.02 degrees C, 0.25 +/- 0.03 degrees C, 0.4 +/- 0.05 degrees C were observed at 30, 60 min after inflation, and just before deflation, respectively in group L, and the increase of 0.11 +/- 0.03 degrees C and 0.18 +/- 0.03 degrees C at 30 min after inflation and just before deflation, respectively in group S. Temperatures from 2 to 10 min after deflation were significantly lower than value of just before deflation in each group (P < 0.05). At 10 min after deflation, 0.76 +/- 0.13 degrees C in group L and 0.4 +/- 0.04 degrees C in group S were lower than values of just before deflation in each group (P < 0.05). Temperature at 10 min after deflation was significantly different between the groups (P < 0.05). CONCLUSIONS: Extent of core temperature decrease after tourniquet deflation was dependent on the duration of tourniquet application.
Arthroscopy ; Humans ; Inflation, Economic ; Knee ; Tourniquets*

BACKGROUND: Venous lidocaine retention with tourniquet has a possibility to prevent propofol injection pain efficiently. We performed the study to assess the efficacy of various intravenous lidocaine pretreatment methods with tourniquet on reducing propofol-induced injection pain, especially the effect of varying the concentration and dose of lidocaine. METHODS: In order to know the effect of lidocaine pretreatment with tourniquet on prevention of propofol-induced injection pain, one hundred patients were divided into four groups by the method of pretreatment; 1% lidocaine of 1 mg/kg (lidocaine pretreatment, LPT1 n = 25); 0.5% lidocaine of 1 mg/kg (LPT2, n = 25); 1% lidocaine of 0.5 mg/kg (LPT3, n = 25); 5 ml of saline pretreatment (saline pretreatment, SPT, n = 25). After 5 minutes of pretreatment, propofol-induced pain was measured immediately after injection of 1 mg/kg propofol with tourniquet inflation and after deflation of tourniquet, and after a second injection of 1 mg/kg propofol by use of the numerical rating scale and pain score of four categories. We selected maximal values of three times measurement for comparison. RESULTS: All groups of lidocaine pretreatment (pain incidence of LPT1; 20%, LPT2; 16% and LPT3; 36%, respectively) significantly reduced the incidence of propofol-induced injection pain compared to the saline pretreatment group (96%) (P <0.05). Lidocaine pretreatment groups had dramatically lower intensity of pain compared with saline pretreatment (P <0.05). However, there were no differences among the lidocaine pretreatment groups (P > 0.05). CONCLUSIONS: This result indicates that lidocaine pretreatment with tourniquet has an effect on the prevention of propofol-induced injection pain. However, we recommend pretreatment with 0.5 1% lidocaine of 1 mg/kg by use of tourniquet and propofol injection immediately after deflation of the tourniquet in practice.
Humans ; Incidence ; Inflation, Economic* ; Lidocaine* ; Propofol* ; Tourniquets*

PURPOSE: Inflation of an endotracheal tube cuff with adequate pressure is an important procedure. Passive release technique (PRT) is a useful and convenient method for inflating the cuff. To date, no study comparing this method with minimal occlusive volume technique (MOVT), one of the most commonly used methods for inflating the cuff, has been reported. We conducted this study for comparison of effectiveness, difficulty, and preference between the two methods. METHODS: We conducted a prospective, crossover, randomized study in which participants used each technique, one at a time. Participants inflated the cuff of an endotracheal tube inserted into a manikin after receiving brief education on use of the two methods. After inflating the cuff using each method, pressure and volume of the inflated cuff were measured using a portable manometer and syringes, respectively. Then, difficulty of each method was investigated using the visual analogue scale (VAS) and preference for each method was investigated. RESULTS: A total of 47 participants were enrolled in the study. The mean pressure between the two methods was not statistically different (p=0.27). However, adequate pressure was achieved in 37 (78.7%) and 16 (34.0%) of participants in PRT and MOVT, respectively (p<0.01). The mean volume was 6.0+/-0.4 ml in PRT and 5.7+/-0.6 ml in MOVT (p<0.01). The VAS score for diffculty was 17.7+/-15.8 in PRT and 76.0+/-15.8 in MOVT (p<0.01). Preference for PRT was 46(97.9%) and that for MOVT was 1 (2.1%). CONCLUSION: PRT is an easier, more preferred, and more effective method for cuff inflation than MOVT.
Inflation, Economic ; Intubation ; Manikins ; Prospective Studies ; Syringes

Analysis of variance (ANOVA) is one of the most frequently used statistical methods in medical research. The need for ANOVA arises from the error of alpha level inflation, which increases Type 1 error probability (false positive) and is caused by multiple comparisons. ANOVA uses the statistic F, which is the ratio of between and within group variances. The main interest of analysis is focused on the differences of group means; however, ANOVA focuses on the difference of variances. The illustrated figures would serve as a suitable guide to understand how ANOVA determines the mean difference problems by using between and within group variance differences.
Analysis of Variance* ; False Positive Reactions ; Inflation, Economic

The purpose of this study compares determinants of eldery medical cost inflation with those of other age groups by analysing aggregated data with a deterministic model. The deterministic model of per capita medical cost inflation consists of increases in price, intensity of services, and medical utilization. We used a time series data (1985-1991) from National Medical Insurance and analyzed by age groups. In total population, the average increase rates of inpatient and outpatient medical costs were respectively 9.5% and 8.8% during 6 years and the major cause of inflation was the increase in service intensity in both of inpatient and outpatient cases. But in the population of 65 years old and over, the average increase rates of inpatient and outpatient medical costs were respectively 13.8% and 14.8% and the major cause of inflation was the increase in per-capita medical utilization in both of inpatient and outpatient cases. Also, the increase in service intensity of 65 years old and over was the highest of other age groups. This pattern was similar during study periods. we concluded that the level of medical cost inflation and the determinants in elderly was the highest-especially in per capita medical utilization, therefore, the inflation of medical costs in elderly will be higher than other age groups for the further in Korea.
Aged* ; Humans ; Inflation, Economic* ; Inpatients ; Insurance ; Korea ; Outpatients

BACKGROUND: The intracoronary stent implantation is regarded as an effective treatment modality to reduce restenosis. However, subacute stent thrombosis and subsequent anticoagulation therapy have been major problems after stenting. The high-pressure inflation stenting reduced the incidence of stent thrombosis and resulted in less need of anticoagulation therapy. We intended to analyze the high-pressure inflation stenting with intravascular ultrasound(IVUS) and to evaluate different IVUS criteria of optimal stenting. METHOD: One hundred and forty eight patients with 160 lesions were treated with 175 stents of various types. IVUS images were obtained after angiographic optimization (<10% of residual stenosis) with high-pressure inflation stenting. The quantitative and qualitative off-line measurements of IVUS parameters were performed. RESULTS: More high-pressure or larger-sized balloon inflation was needed in 32 lesions (20%) after IVUS. The incomplete stent apposition was observed in 5 lesions (3%). The edge dissection occurred distally or proximally to stented site in 19 lesions (12%). The plaque prolapse was observed within the stent in 24 lesions (15%). In single stent implantation for discrete lesions, optimal stent expansion defined by IVUS was achieved in 69% with minimal stent lumen area of 90% of distal reference lumen area and in 75% with minimal stent lumen area of 80% of average reference lumen area. The IVUS criteria of minimal stent lumen area 9mm2 and 7-9mm2 was met in 29% and 29%, respectively. In stents implantation for diffuse lesions including long stent,multiple overlapping stents and hybrid stents implantation, optimal stent expansion defined by IVUS was achieved in 69% with minimal stent lumen area of 90% of distal reference lumen area and in 67% with minimal stent lumen area of 80% of average reference lumen area. The IVUS criteria of minimal stent lumen area 9mm2 and 7-9mm2 was met in 17% and 23%, respectively. CONCLUSION: IVUS provided a valuable informations leading to additional intervention in 20% of the lesions after angiographic optimization with high-pressure balloon inflation. Even though additional interventions were performed with IVUS-guidance, the optimal stent expansion by IVUS criteria was achieved in about 70%. Therefore, we suggest that IVUS might be used more generally to improve the acute results after coronary stenting.
Humans ; Incidence ; Inflation, Economic* ; Prolapse ; Stents* ; Thrombosis ; Ultrasonography*

The development of endotracheal tubes with high-volume and low-pressure cuffs has decreas ed the incidence of associated tracheal injury. If room air used for inflation of the cuff during general anesthesia using N2O-O2, mixtures, however, endotracheal tube cuff result in distention and potential pressure changes. Therefore, tracheal pressure injury may occur during long general anesthesia(especially, head and neck surgery). For the prevention of this problems and the determination of proper methods, we performed this study relating to nitrous oxide diffusion into a gas filled endotracheal tube cuff.
Anesthesia, General ; Diffusion ; Head ; Incidence ; Inflation, Economic ; Neck ; Nitrous Oxide*

Primary coronary stenting is one of the established therapeutic options for acute myocardial infarction. The risk of balloon rupture during stenting may be increased after high pressure inflation technique was introduced. Balloon rupture during stenting may cause catastrophic complications such as extensive dissection, acute closure, coronary perforation. We report a case of balloon rupture during primary stenting in acute myocardial infarction, which caused acute thrombotic closure of target and remote coronary arteries simultaneously.
Coronary Vessels* ; Inflation, Economic ; Myocardial Infarction* ; Rupture* ; Stents*