Differences in Perspectives of Medical Device Adverse Events: Observational Results in Training Program Using Virtual Cases

BACKGROUND: Medical device adverse event reporting is an essential activity for mitigating device-related risks. Reporting of adverse events can be done by anyone like healthcare workers, patients, and others. However, for an individual to determine the reporting, he or she should recognize the current situation as an adverse event. The objective of this report is to share observed individual differences in the perception of a medical device adverse event, which may affect the judgment and the reporting of adverse events. METHODS: We trained twenty-three participants from twelve Asia-Pacific Economic Cooperation (APEC) member economies about international guidelines for medical device vigilance. We developed and used six virtual cases and six questions. We divided participants into six groups and compared their opinions. We also surveyed the country's opinion to investigate the beginning point of ‘patient use’. The phases of ‘patient use’ are divided into: 1) inspecting, 2) preparing, and 3) applying medical device. RESULTS: As for the question on the beginning point of ‘patient use,’ 28.6%, 35.7%, and 35.7% of participants provided answers regarding the first, second, and third phases, respectively. In training for applying international guidelines to virtual cases, only one of the six questions reached a consensus between the two groups in all six virtual cases. For the other five questions, different judgments were given in at least two groups. CONCLUSION: From training courses using virtual cases, we found that there was no consensus on ‘patient use’ point of view of medical devices. There was a significant difference in applying definitions of adverse events written in guidelines regarding the medical device associated incidents. Our results point out that international harmonization effort is needed not only to harmonize differences in regulations between countries but also to overcome diversity in perspectives existing at the site of medical device use.

The location of locoregional recurrence in pathologic T3N0, non-irradiated lower rectal cancer

PURPOSE: To investigate the patterns of locoregional recurrence of pathologic T3N0 (pT3N0) lower rectal cancer omitting postoperative radiotherapy (RT) and explore the potential of modification of a RT field. MATERIALS AND METHODS: From Jan 2003 to Nov 2011, 35 patients omitting preoperative or postoperative RT for pT3N0 lower rectal cancer were included. We defined the lower rectal cancer as the tumor with the inferior margin located below the virtual line-a convergent level between rectal wall and levator ani muscle. All patients had radiologic examinations for recurrence evaluation during the follow-up duration. RESULTS: The median follow-up duration was 66.4 months (range, 1.4 to 126.1 months). Eight (22.9%) of the 35 patients had recurrence. Three (8.6%) was local recurrence (LR) only, 3 (8.6%) was distant metastasis (DM) only, and 2 (5.7%) was LR with DM. All LR were located at primary tumor sites. The overall survival rate, LR-free survival rate, and DM-free survival rate at 5 years was 79.8%, 83%, and 87%, respectively. All LR developed from tumors over 5 cm. However, there was no statistical significance (p = 0.065). There was no other risk factor for LR. CONCLUSION: Even though the patients included in this study had pathologically favorable pT3N0 rectal cancer, LR developed in 14.3% of patients. Most of the LR was located at primary tumor sites prior to surgery. Based on these findings, it might seem reasonable to consider postoperative RT with a smaller radiation field to the primary tumor site rather than the conventional whole pelvic irradiation.

The Impact of Cigarette Smoking on the Frequency of and Qualitative Differences in KRAS Mutations in Korean Patients with Lung Adenocarcinoma

PURPOSE: This study was designed to determine the relationship of cigarette smoking to the frequency and qualitative differences among KRAS mutations in lung adenocarcinomas from Korean patients. MATERIALS AND METHODS: Detailed smoking histories were obtained from 200 consecutively enrolled patients with lung adenocarcinoma according to a standard protocol. EGFR (exons 18 to 21) and KRAS (codons 12/13) mutations were determined via direct-sequencing. RESULTS: The incidence of KRAS mutations was 8% (16 of 200) in patients with lung adenocarcinoma. KRAS mutations were found in 5.8% (7 of 120) of tumors from never-smokers, 15% (6 of 40) from former-smokers, and 7.5% (3 of 40) from current-smokers. The frequency of KRAS mutations did not differ significantly according to smoking history (p=0.435). Never-smokers were significantly more likely than former or current smokers to have a transition mutation (G-->A or C-->T) rather than a transversion mutation (G-->T or G-->C) that is known to be smoking-related (p=0.011). In a Cox regression model, the adjusted hazard ratios for the risk of progression with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) were 0.24 (95% CI, 0.14-0.42; p<0.001) for the EGFR mutation and 1.27 (95% CI, 0.58-2.79; p=0.537) for the KRAS mutation. CONCLUSION: Cigarette smoking did not influence the frequency of KRAS mutations in lung adenocarcinomas in Korean patients, but influenced qualitative differences in the KRAS mutations.

Effects of Posture and Acute Sleep Deprivation on Heart Rate Variability

PURPOSE: In our previous study to investigate autonomic nervous system (ANS) activity due to radio frequency (RF) radiation using heart rate variability (HRV), drowsiness was observed in approximately half of all subjects. Therefore, the usage of HRV with unwanted drowsiness could falsely indicate the effects of RF radiation by mobile phones on the ANS. The objective of this study was to determine which posture is appropriate for accurate HRV analysis for provocation study. MATERIALS AND METHODS: A total of 52 healthy subjects (25 males and 27 females) participated in this experiment. We measured the number of times a subject showed drowsiness or sleep deprivation due to awakening, and analyzed HRV six times over 30 minutes in sitting and recumbent postures, using power spectrum. RESULTS: We employed the ratio of low frequency power to high frequency power (LFP/HFP) to analyze the changes in the ANS. The number of sleep deprivation occurrences in the sitting posture was significantly less than that in the recumbent posture (p<0.01), resulting in smaller increase of LFP/HFP. Although LFP/HFP of the two postures varied with time without any provocation, it was more stable in sitting than in recumbent postures. CONCLUSION: A sitting posture is preferable to a recumbent posture for analyzing HRV, because of decreased drowsiness and sleep deprivation, thereby decreasing variation of LFP/HFP during experiment. Considering the drowsiness, it is also recommended that any experiment should be completed within 15 minutes, if possible.

Real-Time Measurement of 3-Dimensional Eye Movements by Videooculography

BACKGROUND AND OBJECTIVES:In order to analyze and understand the oculomotor system completely, it is essential to measure horizontal, vertical, and torsional eye movements. We developed a new system of 3-dimensional videooculography that can accurately estimate the pupil center and measure torsional eye movement in real time while minimizing the errors caused by upper eyelid droop, eyelashes, corneal reflection, and eye blinking. MATERIALS AND METHOD:For accurate estimation of the center and diameter of the pupil, the edges of the pupil were searched by using a sector-form window and circle fitting was performed using the least square regression. Torsional eye movement was measured using polar cross-correlation technique with modification to lessen the errors produced by the change in pupil size. Calibrations were performed and to verify the proposed system, the linearity between the measured and actual eye movements was measured. Also, the results of the proposed system were compared with those of another commercialized system. RESULTS: The linearity between the measured and actual eye movements showed errors of less than 1%. The spatial resolutions of the system for horizontal, vertical, and torsional eye movements were 0.3, 0.4, and 0.2, respectively whereas the temporal resolution was 30 frames/sec. In comparison to the commercialized system, our system showed less artifact by eye blinking when measuring vertical eye movement. CONCLUSION:We proposed an algorithm and a system for measuring horizontal, vertical, and torsional eye movements which minimized the influence of partial eyelid closure, eyelashes, corneal reflections, and change in pupil size.

Measurement of the excessive stimulus time after the sensory threshold level during electric pulp testing / 대한치과보존학회지

Use of electric pulp testing elicits painful response in vital teeth. In this study, we examined the excessive time from pain feeling to stimulation disconnection in clinical situation. D626D (Parkell Inc., USA.) scan type electric pulp tester was used in total of 23 young healthy individuals. Each of the right central incisors and first premolars were used as testing teeth. Stimulation disconnection was achieved by EMG in anterior belly of digastric muscle, finger span, and voice and the excessive stimulation time over the sensory threshold was recorded. As a result, we found that the short responses before the stimulation disconnection appeared following order; EMG, finger span, and voice. The EMG disconnection is suggested to be used to reduce the excessive stimulus time in electric pulp testing.

Evaluation of a Bio-impedance Method for Measuring Human Arm Movement

This study proposes a new method for measuring upper limb movement using a bio-impedance technique. Bio-impedance and joint angle were simultaneously measured during the wrist and elbow movements of 12 normal subjects. The joint angles of the wrist and elbow were estimated by measuring the bio-impedances of the forearm and upper arm, respectively. Although the measured bio-impedances on upper limbs varied among individuals, changes in the bio-impedances and joint angles of the wrist and elbow during their extension and flexion were very highly correlated, having correlation coefficients of 0.96 +/- 0.04 and -0.98 +/- 0.02, respectively. The reproducibilities of wrist and elbow bio-impedance changes were 2.1 +/- 1.0% and 1.8 +/- 1.0%, respectively. Since the proposed method is not restricted by size or the duration of measurements, it is expected to be useful for the analysis of athletic movement.

Galvanic Nystagmus in Normal Person

BACKGROUND AND OBJECTIVES: Vestibulo-ocular reflex and vestibulo-spinal reflex are induced by transmatoid galvanic stimulation of vestibular system. Nystagmus and body sway are result of each reflex. Recently, videooculograph possible to record a minute ocular movement was commonly used, vestibulo-ocular reflex induced by galvanic simualtion is easily documented. The purposes of this study are to evaluate the galvanic nystagmus in nomal persons in order to better understand the physiology of the vestibular system. MATERIALS AND METHODS: Eye movement of 20 neurootologic normal subjects by both side transmstoid galvanic stimulation (40cases) were analyzing by videonystagmography. RESULT: The direction of nystagmus in fast phase was to the negative electrode. Galvanic nystagmus was occured all normal subjects when stimulus intensity was more than 2mA. There was positive correlation between slow phase velocity(SPV) and electric current but negative correlation was noted between asymmery of SPV and electric current. CONCLUSION: It is suggested that the galvanic nystagmus test could be a new diagnostic tool for evaluation of vestibular status.

How Much are Anesthesiologists Exposed to Electromagnetic Fields in Operating Rooms? / 대한마취과학회지

BACKGROUND: So many electronic devices have been introduced in the operating room. However, little was known about the hazards of electromagnetic fields (EMF) to the human body. We have studied about how much the anesthesiologists are exposed to EMF. METHODS: In 19 operating rooms of our hospital, the intensity of magnetic fields was measured by an ELF (Extremely low frequency) field strength measurement system. The distances were 30 cm, 50 cm and the anesthesiologist's proximity to the monitoring devices. RESULTS: The average strength of 19 operating rooms were 2.22 +/- 1.13 mG at 30 cm from the monitors, 1.29 +/- 0.84 mG at 50 cm and 1.00 +/- 0.78 mG at the anesthesiologist's stand. CONCLUSIONS: We found that in some of our operating rooms the exposure to EMF was measured above Sweden's TCO limit which has been accepted as the EMF radiation rule for computer monitors. Although the hazards of EMF have not been definitely confirmed yet, the effort not to be exposed to EMF should be considered by anesthesiologists.