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

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

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*

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: Accurate placement of double-lumen endobronchial tube(DLT) is essential for successful one-lung anesthesia. This study was performed to evaluate the effectiveness of bronchial cuff inflation technique for accurate placement of DLT. METHODS: One hundred and five patients undergoing elective thoracotomy which required the use of DLTs were studied. Following induction of anesthesia, the tip of the left-sided DLT was advanced just past the vocal cords, the stylet in the endobronchial lumen was removed and the tube was rotated 90 degrees counterclockwise. After rotation of DLT, the bronchial cuff was inflated with air(4-6 ml) and the tube was advanced until resistance to further passage was encountered. After deflating of the bronchial cuff, the tube was advanced 2 cm more distally. The fiberoptic bronchoscopy was then introduced into the tracheal lumen of the tube and the tube's position was evaluated. RESULTS: In the 100 patients out of 105 patients, the tube was inserted into the left side bronchus correctly. In the 77 patients(77 %) out of 100 patients, the position of DLTs was evaluated as ideally placed. In the 16 patients(16 %), the tube was evaluated as too deeply inserted into the appropriate bronchus and in the other 7 patients, the tube was too shallow. But only one patient needed repositioning. CONCLUSIONS: Bronchial cuff inflation technique may be useful for accurate placement of DLT for the one-lung anesthesia in the situation without fiberoptic bronchoscope.
Anesthesia ; Bronchi ; Bronchoscopes ; Bronchoscopy ; Humans ; Inflation, Economic* ; Thoracotomy ; Vocal Cords

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*

BACKGROUND AND OBJECTIVES: Intravascular ultrasound (IVUS), following stent implantation, demonstrated a significant degree of underexpansion, despite the initial appearance of an angiographically successful deployment, in first-generation stents. With improvements in stent designs and delivery systems, the current-generation of stents appear to achieve optimal stent expansion. The purpose of this study was to evaluate optimal stent expansion, by nominal pressure balloon inflation, in the current generation of stents. SUBJECTS AND METHODS: We evaluated 30 patients having had Nir-Sox, Tristar, S670 or Bx Velocity stents successfully deployed at nominal pressure (7-10 atm) with delivery balloon system, between March and September 2001, using IVUS. IVUS criterion for optimal stent expansion was defined as a minimal stent area (MSA) ratio of > OR =0.8 of the average reference lumen area. RESULTS: The mean nominal balloon pressure was 8.87+/-0.9 atmospheres and the mean stent size was 3.38+/-0.45 mm. In reference segments, the minimal lumen diameter and average lumen area, found from the IVUS, were 3.18+/-0.51 mm and 8.88+/-2.92 mm 2 , respectively. In stented segments, the minimal stent diameter and MSA were 2.55+/-0.46 mm and 6.10+/-2.08 mm 2 , respectively. In only 11 of the 30 patients (36.7%) was the optimal stent expansion, by IVUS, achieved. CONCLUSION: Despite the development of a balloon delivery system for the current generation of stents, 63.3% of our study patients did not achieve optimal stent expansion, by IVUS, following nominal balloon inflation. Therefore, additional procedure will be required for optimal stent expansion in the current generation of stents.
Atmosphere ; Coronary Disease ; Humans ; Inflation, Economic* ; Stents* ; Ultrasonography* ; Ultrasonography, Interventional

Foley balloon defying deflation were met in 15 cases among 514 patients who were admitted to the Woo Sok Hospital, Korea University College of Medicine during the period the period of l year from Sep. 1971 to Aug. 1972. The cause of these defying deflation were carefully studied in each catheter. An experimental study was also performed for the determination of the defying deflation mechanism by inflating balloon with water on 100 new Foley catheters and incubating them at 37'C for a week. Air in the balloon is also tested. A new simple technique for deflation was devised and applied successfully in all cases The results obtained are summarized as follows: 1. In 13 out of 15 Foley balloon defying deflation were found that valvular mechanism of internal orifice of the inflation tube was the cause and that this deflation occurs in only uneven and upward type Foley catheter in which the more inflation fluid in the balloon the longer internal orifice. which works as valve. (Fig. 2, 3, 4) 2. Adhesion between balloon and internal orifice were found in 2 out of 15 cases and no inflation or deflation was allowed in this type. 3. A11 of these 15 cases were successful deflated by the use of a stainless steel ureteral catheter stylet through the inflation tube. (Fig. 1) 4. Air in the balloon disappears spontaneously in 12-24 hours. 5. No specific sequelae were encountered during or after stylet manipulation.
Catheters ; Humans ; Inflation, Economic ; Korea ; Stainless Steel ; Urinary Catheters ; Water