• 대한의용생체공학회:의공학회지
• /
• 제44권6호
• /
• pp.363-376
• /
• 2023

According to the COVID-19, development of various medical software based on IoT(Internet of Things) was accelerated. Especially, interest in a central software system that can remotely monitor and control ventilators is increasing to solve problems related to the continuous increase in severe COVID-19 patients. Since medical device software is closely related to human life, this study aims to develop central monitoring system that can remotely monitor and control multiple ventilators in compliance with medical device software development standards and to verify performance of system. In addition, to ensure the safety and reliability of this central monitoring system, this study also specifies risk management requirements that can identify hazardous situations and evaluate potential hazards and confirms the implementation of cybersecurity to protect against potential cyber threats, which can have serious consequences for patient safety. As a result, we obtained medical device software manufacturing certificates from MFDS(Ministry of Food and Drug Safety) through technical documents about performance verification, risk management and cybersecurity application.The purpose of this study is to conduct a usability assessment to ensure that ergonomic design has been applied so that the ventilator central monitoring system can improve user satisfaction, efficiency, and safety. The rapid spread of COVID-19, which began in 2019, caused significant damage global medical system. In this situation, the need for a system to monitor multiple patients with ventilators was highlighted as a solution for various problems. Since medical device software is closely related to human life, ensuring their safety and satisfaction is important before their actual deployment in the field. In this study, a total of 21 participants consisting of respiratory staffs conducted usability test according to the use scenarios in the simulated use environment. Nine use scenarios were conducted to derive an average task success rate and opinions on user interface were collected through five-point Likert scale satisfaction evaluation and questionnaire. Participants conducted a total of nine use scenario tasks with an average success rate of 93% and five-point Likert scale satisfaction survey showed a high satisfaction result of 4.7 points on average. Users evaluated that the device would be useful for effectively managing multiple patients with ventilators. However, improvements are required for interfaces associated with task that do not exceed the threshold for task success rate. In addition, even medical devices with sufficient safety and efficiency cannot guarantee absolute safety, so it is suggested to continuously evaluate user feedback even after introducing them to the actual site.

• Yonsei Medical Journal
• /
• 제59권9호
• /
• pp.1088-1095
• /
• 2018

Purpose: Post-operative pulmonary function is an important prognostic factor for lung transplantation. The purpose of this study was to identify factors affecting recovery of forced expiratory volume in 1 second (FEV1) at the first year after lung transplantation. Materials and Methods: We retrospectively reviewed the medical records of lung transplantation patients between October 2012 and June 2016. Patients who survived for longer than one year and who underwent pulmonary function test at the first year of lung transplantation were enrolled. Patients were divided into two groups according to whether they recovered to a normal range of FEV1 (FEV1 ${\geq}80%$ of predicted value vs. <80%). We compared the two groups and analyzed factors associated with lung function recovery. Results: Fifty-eight patients were enrolled in this study: 28 patients (48%) recovered to a FEV1 ${\geq}80%$ of the predicted value, whereas 30 patients (52%) did not. Younger recipients [odds ratio (OR), 0.92; 95% confidence interval (CI), 0.87-0.98; p=0.010], longer duration of mechanical ventilator use after surgery (OR, 1.14; 95% CI, 1.03-1.26; p=0.015), and high-grade primary graft dysfunction (OR, 8.08; 95% CI, 1.67-39.18; p=0.009) were identified as independent risk factors associated with a lack of full recovery of lung function at 1 year after lung transplantation. Conclusion: Immediate postoperative status may be associated with recovery of lung function after lung transplantation.

• Korean Journal of Radiology
• /
• 제21권11호
• /
• pp.1256-1264
• /
• 2020

Objective: Lung segmentation using volumetric quantitative computed tomography (CT) analysis may help predict outcomes of patients with coronavirus disease (COVID-19). The aim of this study was to investigate the relationship between CT volumetric quantitative analysis and prognosis in patients with COVID-19. Materials and Methods: CT images from patients diagnosed with COVID-19 from February 18 to April 15, 2020 were retrospectively analyzed. CT with a negative finding, failure of quantitative analysis, or poor image quality was excluded. CT volumetric quantitative analysis was performed by automated volumetric methods. Patients were stratified into two risk groups according to CURB-65: mild (score of 0-1) and severe (2-5) pneumonia. Outcomes were evaluated according to the critical event-free survival (CEFS). The critical events were defined as mechanical ventilator care, ICU admission, or death. Multivariable Cox proportional hazards analyses were used to evaluate the relationship between the variables and prognosis. Results: Eighty-two patients (mean age, 63.1 ± 14.5 years; 42 females) were included. In the total cohort, male sex (hazard ratio [HR], 9.264; 95% confidence interval [CI], 2.021-42.457; p = 0.004), C-reactive protein (CRP) (HR, 1.080 per mg/dL; 95% CI, 1.010-1.156; p = 0.025), and COVID-affected lung proportion (CALP) (HR, 1.067 per percentage; 95% CI, 1.033-1.101; p < 0.001) were significantly associated with CEFS. CRP (HR, 1.164 per mg/dL; 95% CI, 1.006-1.347; p = 0.041) was independently associated with CEFS in the mild pneumonia group (n = 54). Normally aerated lung proportion (NALP) (HR, 0.872 per percentage; 95% CI, 0.794-0.957; p = 0.004) and NALP volume (NALPV) (HR, 1.002 per mL; 95% CI, 1.000-1.004; p = 0.019) were associated with a lower risk of critical events in the severe pneumonia group (n = 28). Conclusion: CRP in the mild pneumonia group; NALP and NALPV in the severe pneumonia group; and sex, CRP, and CALP in the total cohort were independently associated with CEFS in patients with COVID-19.

• Tuberculosis and Respiratory Diseases
• /
• 제45권6호
• /
• pp.1252-1264
• /
• 1998

연구배경 : 급성호흡곤란층후군은 기계호흡을 포함한 집중 치료에도 불구하고 일반적으로 사망율이 50%에 이르는 중증 급성폐손상으로 사망률 개선을 위해 지난 10여년간 여러 'sepsis trial'들이 시도되어 왔으며, 기계 호흡관리 전략의 변화로 의미 있는 사망율의 개선을 보이고 있다. 사망에 관련한 인자들로는 패혈증, 장기 손상, 고령, APACHE II 점수등이 있다. 내과계 중환자실에서 기계호흡 치료로 관리된 급성호흡곤란증후군 환자를 대상으로 이러한 인자들이 예후에 미치는 영향을 보고자 하였다. 방 법 : 급성호흡곤란증후군의 진단은 1994 년 ATS-ESICM에서 발표된 진단범주에 근거하였다. 천안 순천향병원에서 1995년 3월부터 1998년 10월까지 호흡기계 중환자실에서 기계호흡 치료로 관리된 급성호흡곤란증후군 환자 40예를 대상으로 후향적 조사하여 다음과 같은 결과를 보았다. 결 과 : 급성호흡곤란증후군 발생원인으로는 각각 패혈증 50%(20/40), 폐렴 30%(12/40), 흡인성 폐렴은 20%(8/40) 이였다. 원인에 따른 사망률은 각각 패혈증이 50%(20/40), 폐렴 67%(8/12), 흡인성폐렴38%(3/8)이였다. 전체 사망율은 60%(24/40)였으며, 28일-사망군에서 사망원인으로 각각 패혈중이 43%(9/21), 다발성장기부전이 29%(6/21), 호흡부전이 19%(4/21)이였다. 28일-생존군(19)과 28일-사망군(21)간에 연령, 성별차이는 없었으며, 급성호흡곤란증후군 발생당시 APACHE II 점수는 각각 $22.82{\pm}3.25$ 및 $24.94{\pm}4.67$, 저산소 점수는 각각 $124.11{\pm}49.10$ 및 $110.33{\pm}55.74$, 장기손상수는 각각 $2.00{\pm}0.94$ 및 $2.12{\pm}0.93$개로 양군간에 차이는 없었다. 발생당시 70세 이상, APACHE II 점수가 26 이상, 저산소점수가 150 미만이였던 예는 양군간에 유의한 차이가 있었다 (p<0.05). 생존군에서 발생 당시 및 3일째에 비해 7일째에 APACHE II 점수, 장기손상수, 저산소점수가 유의하게 호전되었고 (p<0.05), 사망군과 유의한 차이를 보였다 (p<0.05). 사망군에서는 7 일간의 관찰기간동안 장기손상수 및 저산소정수의 변화는 없었으며, 특히 APACHE II 점수는 발생당시에 비해 유의하게 증가하였다(P<0.05). 1995년부터 1998년까지 사망율을 비교한 결과 68%에서 40% 이하로 감소하였으며, 연도별로 연령, APACHE II 점수, 저산소 점수 및 장기손상수는 차이가 없었다. 전년도 및 후년도군 각각에서 첫주에 적용된 평균 호기말양압은 2.8mmHg 및 9.2mmHg였으며(p=0.0001), 일환량은 475.8ml 및 371.8ml로 차이가 있었다(p=0.0013). 결 론 : 급성호흡곤란증후군에서 발생당시 APACHE II 점수 및 저산소점수 정도와 함께 치료경과에 따른 APACHE II 점수, 저산소점수 및 장기손상수 등의 호전여부가 예후에 중요한 것으로 사료되며, 근년에 관찰된 급성호흡곤란증후군의 유의한 사망률 개선에 적어도 호기말양압의 유의한 증가가 영향을 준 것으로 사료되었다.

• Tuberculosis and Respiratory Diseases
• /
• 제50권5호
• /
• pp.540-548
• /
• 2001

Backgrounds : Because ventilator-induced lung injury is partly dependent on the intensity of vascular flow, we hypothesized that hypothermia may attenuate the degree of such an injury through a reduced cardiac output. Methods : Twenty-seven male Sprague-Dawley rats were randomly assigned to normothermia ($37{\pm}1^{\circ}C$)-injurious ventilation (NT-V) group (n=10), hypothermia ($27{\pm}1^{\circ}C$)-injurious ventilation (HT-V) group (n=10), or nonventilated control group (n=7). The two thermal groups were subjected to injurious mechanical ventilation for 20 min with peak airway pressure 30 cm $H_2O$ at zero positive end-expiratory pressure, which was translated to tidal volume $54{\pm}6\;ml$ in the NT-V group and $53{\pm}4\;ml$ in the HT-V group (p>0.05). Results : Pressure-volume (P-V) curve after the injurious ventilation was almost identical to the baseline P-V curve in the HT-V group, whereas it was shifted rightward in the NT-V group. On gross inspection, the lungs of the HT-V group appeared smaller in size, and showed less hemorrhage especially at the dependent regions, than the lungs of the NT-V group. [Wet lung weight (g)/body weight (kg)] ($1.6{\pm}0.1$ vs $2.4{\pm}1.2$ ; p=0.014) and [wet lung weight/dry lung weight] ($5.0{\pm}0.1$ vs $6.1{\pm}0.8$ ; p=0.046) of the HT-V group were both lower than those of the NT-V group, while not different from those of the control group($1.4{\pm}0.4$, $4.8{\pm}0.4$, respectively). Protein concentration of the BAL fluid of the HT-V group was lower than that of the NT-V group($1,374{\pm}726\;ug/ml$ vs $3,471{\pm}1,985\;ug/ml$;p=0.003). Lactic dehydrogenase level of the BAL fluid of the HT-V group was lower than that of the NT-V group ($0.18{\pm}0.10\;unit/ml$ vs $0.43{\pm}0.22\;unit/ml$;p=0.046). Conclusions : Hypothermia attenuated pulmonary hemorrhage, permeability pulmonary edema, and alveolar cellular injuries associated with injurious mechanical ventilation, and preserved normal P-V characteristics of the lung in rats.

• Tuberculosis and Respiratory Diseases
• /
• 제68권3호
• /
• pp.162-167
• /
• 2010

Background: To date, there are few data on the risk factors for severe cases and deaths associated with the 2009 pandemic H1N1 influenza A. Here, we describe the clinical and epidemiologic characteristics of patients hospitalized for pneumonia and identify those factors associated with the development of major complications (MC). Methods: We reviewed the medical records of 41 cases of pneumonia admitted to a university-affiliated tertiary hospital between Aug 26 and Dec 10, 2009, and who had confirmed H1N1 influenza A based on real-time reverse transcriptase-polymerase-chain-reaction assay. There were 7,962 patients that fit these criteria. We compared the clinical features and demographic characteristics of patients who developed MC to with those who did not develop MC. Results: During the study period, 10 patients developed MC (required admission to the intensive care unit, n=10; required ventilator therapy, n=6; death, n=4). Patients with MC were significantly older than those without MC and more frequently had underlying medical conditions (90.0% vs 41.9%, p-value <0.01). In the patients with developed MC, the median $PaO_2/FiO_2$ ratio of 230.0 (145.0~347.3) at admission and pneumonia severity index (PSI) score of 141.5 (88.3~158.5) were higher than patients without MC. However, no differences were observed in laboratory findings or in viral shedding between the 2 groups. Conclusion: In hospitalized pneumonia patients of 2009 H1N1 influenza, old age, a history of malignancy, initial hypoxemia, $PaO_2/FiO_2$ ratio, and PSI score appear to be risk factor significantly related to developing MC. These findings might be the basis to influence strategies for admitting patients to an intensive or intermediate care unit and for pre-emptive antiviral therapy.

• Journal of Gastric Cancer
• /
• 제14권2호
• /
• pp.142-146
• /
• 2014

Pulmonary tumor thrombotic microangiopathy (PTTM) causing fatal pulmonary hypertension is a rare presentation of malignancy. In general, patients with PTTM rapidly succumb to death due to severe hypoxia. To date, very few cases of PTTM have been reported in the literature; and most of these cases were from gastric cancer and were diagnosed on post mortem autopsy, as it is extremely challenging to make an ante mortem diagnosis. We here report on a case of undiagnosed diffuse gastric cancer, presenting as worsening hypoxia. The clinical, radiographic, and echocardiographic features, and laboratory and pathological results were consistent with PTTM from gastric cancer. The patient was started on anticoagulation therapy, corticosteroids, and high-flow oxygen. However, her hypoxia worsened to the extent that she required ventilator support, and she died soon after intubation due to cardiac arrest. Since diffuse gastric cancer is associated with hereditary diffuse gastric cancer syndrome, cadherin 1 gene mutation analysis was performed to estimate the risk to her daughters. The test came back negative.

• 대한임상독성학회지
• /
• 제14권2호
• /
• pp.151-154
• /
• 2016

Increased plasma insulin levels are often observed in exogenous insulin overdose patients. However, plasma insulin level may decrease with time. We report a case of low plasma insulin level hypoglycemia after insulin lispro overdose. The patient was a 37-year-old man with no previous medical history who suspected insulin lispro overdose. Upon arrival, his Glasgow coma scale was 3 points and his blood sugar level (BSL) was 24 mg/dl. We found five humalog-quick-pen (insulin lispro) in his bag. There was no elevation of glucose level, despite an initial 50 ml bolus of 50% glucose and 150 cc/hr of 10% dextrose continuous intravenous infusion. He also suffered from generalized tonic-clonic seizure, which was treated with lorazepam and phenytoin. We conducted endotracheal intubation, after which he was admitted to the intensive care unit (ICU). There were recurrent events of hypoglycemia below BSL<50 mg/dl after admission. We repeatedly infused 50 ml 50% glucose 10 times and administered 1 mg of glucagon two times. The plasma insulin level was 0.2 uU/ml on initial blood sampling and 0.2 uU/ml after 5 hours. After 13 hours, his BSL stabilized but his mental status had not recovered. Diffuse brain injury was observed upon magnetic resonance imaging (MRI) and severe diffuse cerebral dysfunction was found on electroencephalography (EEG). Despite 35 days of ICU care, he died from ventilator associated pneumonia.

• Tuberculosis and Respiratory Diseases
• /
• 제62권5호
• /
• pp.437-440
• /
• 2007

기관절개술은 가장 오래된 수술기술 중의 하나로 상기도 폐쇄의 경감, 장기간의 기계호흡유지, 보조적 기계호흡시에 기도 저항의 감소 등의 목적으로 시행할 수 있다. 기관절개술에 따른 초기합병증으로는 기흉, 피하조직기종, 절개부위 출혈, 종격동 기종, 흡인, 기관절개 관 전위 등을 들 수 있다. 수술에 따른 피하조직기종과 기흉은 0.9-5%에서 보고되었다. 본 증례에서는 기관절개술 직후에 피하조직기종과 양측 폐에서 발생한 긴장성 기흉을 경험하였기에 보고하는 바이다.

• Journal of Chest Surgery
• /
• 제32권11호
• /
• pp.1017-1022
• /
• 1999

Background: An increasing number of elderly are referred for open heart surgeries(OHS). These patients are assumed to have significantly increased morbidity and mortality because of compromised functional reserves in their vital organs. We reviewed the results of OHS patients who were 70 years old or older. Material and Method: Thirty six consecutive septuagenarians underwent OHS from 1995 to 1997. Operations were coronary artery bypass grafting(CABG) in 26 including 3 left main surgical angioplasty, valve replacement in 7, MVR+CABG in 2, and ASD closure+TAP in 1. Statistical tests were carried out to compare survivor group with nonsurvivor group in respect to risk factors including NYHA functional class, LVEF, emergent operation, IABP support, CPB/ACC time, ventilator time cardiac index, ICU stay and hospital stay for operative mortality. Result: Operative mortality rate and postoperative complication were 16%(6/36) and 50%(18/36). One-year and 3-year actuarial survival rates were 76%. Nine patients(25%) had major complications including third-degree A-V block(2), respiratory failure(1), stroke(3), renal failure requiring dialysis(3) and postoperative hemorrhage(2). The causes of death were pneumonia(1), bleeding(1), acute renal failure(1), low cardiac output(1), third-degree A-V block(1), and ventricular tachycardia(1). The univariate analysis of mortality shows that NYHA class IV, LVEF<40%, lesser values for C.I, and longer time for ventilatory support were associated with the risk factors(p value=0.03, 0.001, 0.007, and 0.014). The emergent operation, CPB/ACC time, IABP support, ICU stay and hospital stay were not significant. Conclusion: We conclude that cardiac operation can be performed in septuagenarians with acceptable outcomes when done in patients with normal to moderately depressed left ventricular function and adequate functional reserves in their vital organs.