Medical Resource Consumption and Quality of Life in Peripheral Arterial Disease in Korea: PAD Outcomes (PADO) Research

BACKGROUND AND OBJECTIVES@#We aimed to investigate the history of medical resource consumption and quality of life (QoL) in peripheral arterial disease (PAD) patients in Korea.@*METHODS@#This was a prospective, multi-center (23 tertiary-hospitals, division of cardiology), non-interventional study. Adult patients (age ≥20 years) suffering from PAD for the last 12-month were enrolled in the study if they met with any of following; 1) ankle-brachial index (ABI) ≤0.9, 2) lower-extremity artery stenosis on computed tomography angiography ≥50%, or 3) peak-systolic-velocity-ratio (PSVR) on ultrasound ≥2.0. Medical chart review was used to assess patient characteristics/treatment patterns while the history of medical resource consumption and QoL data were collected using a patient survey. QoL was measured using EuroQoL-5-dimensions-3-level (EQ-5D-3L) score system, and the factors associated with QoL were analyzed using multiple linear regression analysis.@*RESULTS@#This study included 1,260 patients (age: 69.8 years, male: 77.0%). The most prevalent comorbidities were hypertension (74.8%), hyperlipidemia (51.0%) and diabetes-mellitus (50.2%). The 94.1% of the patients took pharmacotherapy including aspirin (76.2%), clopidogrel (53.3%), and cilostazol (33.6%). The 12.6% of the patients were receiving smoking cessation education/pharmacotherapy. A considerable number of patients (500 patients, 40.0%) had visit history to another hospital before diagnosis/treatment at the current hospital, with visits to orthopedic units (50.4%) being the most common. At the time, 29% (or higher) of the patients were already experiencing symptoms of critical limb ischemia. Baseline EQ-5D index and EQ VAS were 0.64±0.24 and 67.49±18.29. Factors significantly associated with QoL were pharmacotherapy (B=0.05053; p=0.044) compared to no pharmacotherapy, and Fontaine stage improvement/maintain stage I (B=0.04448; p < 0.001) compared to deterioration/maintain stage II–IV.@*CONCLUSIONS@#Increase in disease awareness for earlier diagnosis and provision of adequate pharmacotherapy is essential to reduce disease burden and improve QoL of Korean PAD patients.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea / 한국역학회지

OBJECTIVES@#The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status.@*METHODS@#Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results.@*RESULTS@#The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis.@*CONCLUSIONS@#The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

Medical Resource Consumption and Quality of Life in Peripheral Arterial Disease in Korea: PAD Outcomes (PADO) Research

BACKGROUND AND OBJECTIVES: We aimed to investigate the history of medical resource consumption and quality of life (QoL) in peripheral arterial disease (PAD) patients in Korea. METHODS: This was a prospective, multi-center (23 tertiary-hospitals, division of cardiology), non-interventional study. Adult patients (age ≥20 years) suffering from PAD for the last 12-month were enrolled in the study if they met with any of following; 1) ankle-brachial index (ABI) ≤0.9, 2) lower-extremity artery stenosis on computed tomography angiography ≥50%, or 3) peak-systolic-velocity-ratio (PSVR) on ultrasound ≥2.0. Medical chart review was used to assess patient characteristics/treatment patterns while the history of medical resource consumption and QoL data were collected using a patient survey. QoL was measured using EuroQoL-5-dimensions-3-level (EQ-5D-3L) score system, and the factors associated with QoL were analyzed using multiple linear regression analysis. RESULTS: This study included 1,260 patients (age: 69.8 years, male: 77.0%). The most prevalent comorbidities were hypertension (74.8%), hyperlipidemia (51.0%) and diabetes-mellitus (50.2%). The 94.1% of the patients took pharmacotherapy including aspirin (76.2%), clopidogrel (53.3%), and cilostazol (33.6%). The 12.6% of the patients were receiving smoking cessation education/pharmacotherapy. A considerable number of patients (500 patients, 40.0%) had visit history to another hospital before diagnosis/treatment at the current hospital, with visits to orthopedic units (50.4%) being the most common. At the time, 29% (or higher) of the patients were already experiencing symptoms of critical limb ischemia. Baseline EQ-5D index and EQ VAS were 0.64±0.24 and 67.49±18.29. Factors significantly associated with QoL were pharmacotherapy (B=0.05053; p=0.044) compared to no pharmacotherapy, and Fontaine stage improvement/maintain stage I (B=0.04448; p < 0.001) compared to deterioration/maintain stage II–IV. CONCLUSIONS: Increase in disease awareness for earlier diagnosis and provision of adequate pharmacotherapy is essential to reduce disease burden and improve QoL of Korean PAD patients.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea / 한국역학회지

OBJECTIVES: The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status.METHODS: Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results.RESULTS: The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis.CONCLUSIONS: The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea / 한국역학회지

OBJECTIVES: The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status. METHODS: Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results. RESULTS: The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis. CONCLUSIONS: The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

Hepatitis E virus as an emerging zoonotic pathogen

Hepatitis E outbreaks are a serious public health concern in developing countries. The disease causes acute infections, primarily in young adults. The mortality rate is approximately 2%; however, it can exceed 20% in pregnant women in some regions in India. The causative agent, hepatitis E virus (HEV), has been isolated from several animal species, including pigs. HEV genotypes 3 and 4 have been isolated from both humans and animals, and are recognized as zoonotic pathogens. Seroprevalence studies in animals and humans indirectly suggest that HEV infections occur worldwide. The virus is primarily transmitted to humans via undercooked animal meats in developed countries. Moreover, transfusion- and transplantation-mediated HEV infections have recently been reported. This review summarizes the general characteristics of hepatitis E, HEV infection status in animals and humans, the zoonotic transmission modes of HEV, and HEV vaccine development status.

Endothelial Dysfunction: Clinical Implications in Cardiovascular Disease and Therapeutic Approaches

Atherosclerosis is a chronic progressive vascular disease. It starts early in life, has a long asymptomatic phase, and a progression accelerated by various cardiovascular risk factors. The endothelium is an active inner layer of the blood vessel. It generates many factors that regulate vascular tone, the adhesion of circulating blood cells, smooth muscle proliferation, and inflammation, which are the key mechanisms of atherosclerosis and can contribute to the development of cardiovascular events. There is growing evidence that functional impairment of the endothelium is one of the first recognizable signs of development of atherosclerosis and is present long before the occurrence of atherosclerotic cardiovascular disease. Therefore, understanding the endothelium's central role provides not only insights into pathophysiology, but also a possible clinical opportunity to detect early disease, stratify cardiovascular risk, and assess response to treatments. In the present review, we will discuss the clinical implications of endothelial function as well as the therapeutic issues for endothelial dysfunction in cardiovascular disease as primary and secondary endothelial therapy.

Azidothymidine and recombinant human interferon-alpha therapy in a cat with feline immunodeficiency virus / 동물의과학연구지

A 7-year-old, spayed female, domestic short hair cat showed signs of a 2-week history of chronic anorexia, depression, and severe weight loss. Upon physical examination, pyrexia, mild gingivitis, and pale mucus membranes were noted. Laboratory analysis revealed normocytic normochromic non-regenerative anemia, severe thrombocytopenia, and hypergammaglobulinemia. Serum protein electrophoresis revealed the presence of elevated alpha-2 fraction within the globulin concentration. Based on history, clinical signs, and laboratory results, systemic viral infection was strongly suspected. Reverse transcriptase polymerase chain reaction identified the presence of feline immunodeficiency virus (FIV) in the serum. Furthermore, gene sequencing revealed the virus as FIV subtype A. Treatment with anti-retroviral agents, including azidothymidine (AZT) and recombinant human interferon-alpha, was continued for 4 weeks. However, the patient's clinical condition deteriorated, resulting in death 1 month after initiation of treatment due to progressive renal failure. Necropsy and histopathology revealed hepatic and renal necrosis with hyper-cellular bone marrow mainly comprised of myeloid precursor cells. This case report is the first to describe phylogenetic subtyping, anti-retroviral combination treatment, and clinical outcomes in an FIV-infected cat in Korea. In addition, this report suggests that treatment should be initiated during the early phase of infection that could be effective for the virus.

Exercise-Induced Intrapulmonary Arteriovenous Shunt in a Patient Complaining of Dyspnea during Strenuous Exercise

A 51-year-old highly fit man presented for dyspnea with strenuous aerobic exercise. The patient was asymptomatic and all tests were normal at rest. With increasing exercise intensity, he suddenly complained of dyspnea and showed a severe exercise-induced hypoxemia with an excessive alveolar-arterial oxygen tension difference. In agitated saline contrast echocardiography at peak exercise, a large amount of left to right shunt was identified after > 5 cardiac cycles, which suggests the presence of exercise-induced intrapulmonary arteriovenous shunt in this patient.

Induction of antibody and interferon-gamma production in mice immunized with virus-like particles of swine hepatitis E virus

Virus-like particles (VLPs) composed of the truncated capsid protein of swine hepatitis E virus (HEV) were developed and immune responses of mice immunized with the VLPs were evaluated. IgG titers specific for the capsid protein of swine HEV were significantly higher for all groups of mice immunized with the VLPs than those of the negative control mice. Splenocytes from mice immunized with the VLPs also produced significantly greater quantities of interferon (IFN)-gamma than interleukin (IL)-4 and IL-10. These newly developed swine HEV VLPs have the capacity to induce antigen-specific antibody and IFN-gamma production in immunized mice.

Hepatitis E virus infections in humans and animals

Hepatitis E has traditionally been considered an endemic disease of developing countries. It generally spreads through contaminated water. However, seroprevalence studies have shown that hepatitis E virus (HEV) infections are not uncommon in industrialized countries. In addition, the number of autochthonous hepatitis E cases in these countries is increasing. Most HEV infections in developed countries can be traced to the ingestion of contaminated raw or undercooked pork meat or sausages. Several animal species, including pigs, are known reservoirs of HEV that transmit the virus to humans. HEVs are now recognized as an emerging zoonotic agent. In this review, we describe the general characteristics of HEVs isolated from humans and animals, the risk factors for human HEV infection, and the current status of human vaccine development.

Impact of Framingham Risk Score, Flow-Mediated Dilation, Pulse Wave Velocity, and Biomarkers for Cardiovascular Events in Stable Angina

Although the age-adjusted Framingham risk score (AFRS), flow-mediated dilation (FMD), brachial-ankle pulse wave velocity (baPWV), high-sensitivity C-reactive protein (hsCRP), fibrinogen, homocysteine, and free fatty acid (FFA) can predict future cardiovascular events (CVEs), a comparison of these risk assessments for patients with stable angina has not been reported. We enrolled 203 patients with stable angina who had been scheduled for coronary angiography (CAG). After CAG, 134 patients showed significant coronary artery disease. During 4.2 yr follow-up, 36 patients (18%) showed CVEs, including myocardial infarction, de-novo coronary artery revascularization, in-stent restenosis, stroke, and cardiovascular death. ROC analysis showed that AFRS, FMD, baPWV, and hsCRP could predict CVEs (with AUC values of 0.752, 0.707, 0.659, and 0.702, respectively, all P<0.001 except baPWV P=0.003). A Cox proportional hazard analysis showed that AFRS and FMD were independent predictors of CVEs (HR, 2.945; 95% CI, 1.572-5.522; P=0.001 and HR, 0.914; 95% CI, 0.826-0.989; P=0.008, respectively). However, there was no difference in predictive power between combining AFRS plus FMD and AFRS alone (AUC 0.752 vs. 0.763; z=1.358, P=0.175). In patients with stable angina, AFRS and FMD are independent predictors of CVEs. However, there is no additive value of FMD on the AFRS in predicting CVEs.

Seroprevalence of hepatitis E virus in zoo animal species in Korea / 대한수의학회지

Hepatitis E virus (HEV) can infect not only human but also several animals. This study has been conducted to evaluate the comprehensive anti-HEV seroprevalence in zoo animals in Korea. Anti-HEV antibodies were identified in 14 of 64 zoo animal species. HEV antibodies were detected for the first time in Eurasian Lynx, Setland Pony, Fallow Deer, Ezo Sika, Formosa Deer, East Wapitis, Barasingha, Corriedale, American Bison, Guanacos, Reticulated Giraffe, and Saanen. These results indicate that the several zoo animal species were exposed to HEV.

Evaluation of Short-Term Use of N-Acetylcysteine as a Strategy for Prevention of Anthracycline-Induced Cardiomyopathy: EPOCH Trial - A Prospective Randomized Study

BACKGROUND AND OBJECTIVES: We investigate to determine whether N-acetylcysteine (NAC) can prevent anthracycline-induced cardiotoxicity. SUBJECTS AND METHODS: A total of 103 patients were enrolled in this prospective randomized open label controlled trial. They are patients first diagnosed with breast cancer or lymphoma, who require chemotherapy, including anthracycline like adriamycine or epirubicine. Patients were randomized to the NAC group {n=50; 1200 mg orally every 8 hours starting before and ending after the intravenous infusion of anthracycline in all chemotherapy cycles (3-6)} or the control group (n=53). Primary outcome was the decrease in left ventricular ejection fraction (LVEF) absolutely > or =10% from the baseline and concomitantly <50% at 6-month. Composite of all-cause death, heart failure and readmission were compared. RESULTS: The primary outcome was not significantly different in the NAC and control groups {3/47 (6.4%) vs. 1/52 (1.9%), p=0.343}. The mean LVEF significantly decreased in both the NAC (from 64.5 to 60.8%, p=0.001) and control groups (from 64.1 to 61.3%, p<0.001) after the completion of whole chemotherapy. The mean LVEF change did not differ between the two groups (-3.64% in NAC vs. -2.78% in control group, p=0.502). Left ventricular (LV) end systolic dimension increased with higher trend in NAC by 3.08+/-4.56 mm as compared with 1.47+/-1.83 mm in the control group (p=0.064). LV end diastolic dimension did not change in each group and change does not differ in both. Peak E, A and E/A ratio change and cardiac enzymes were comparable in two groups. Cumulative 12-month event rate was 6% and 3.8% in the NAC group and the control group, respectively, with no difference (p=0.672). CONCLUSION: We cannot prove that NAC prevents anthracycline-induced cardiomyopathy.

Austrian Syndrome with a Delayed Onset of Heart Failure

A 59-year-old man treated with pneumococcal meningitis 4 months ago was hospitalized for acute heart failure and performed aortic valve replacement by rupture of aortic valve. The frequent association of pneumococcal meningitis and endocarditis is known as Austrian syndrome. Though Austrian syndrome is a clinically rare disease, the evolution of pneumococcal endocarditis is very aggressive and associated with high mortality, and early recognition for evidence of endocardial lesion in patients with pneumococcal meningitis is important to reduce the complications and mortality rate.

An Analysis of Prehospital Care by 119 Rescue Services

PURPOSE: We analysed the prehospital care and property of field triage for quality improvement. METHODS: A retrospective study of 623 case who were selected every five other day(1, 6, 11, 16, 21, 26) and visited emergency center of Hangang Sacred Heart hospital by 119 rescuer from January 2002 to December 2003 was made using triage and management at field and during transport. The research compared 119 transport chart with emergency medical recording. RESULTS: There were 350 male(56.2%) and 273 female(43.8%). Non-triage patient were 432 cases(69.3%). Finding from the crosstabulation analysis between 119 transport chart and emergency medical record reveal that 93 cases were overstimated, and 23 cases were understimated in mental status evaluation by 119 rescuer. Adequate prehospital treatment were 151 cases. CONCLUSION: The property of mental status evaluation by 119 rescuer was nearly correct, but the triage and management were not.

Comparison of the Effects of Nicorandil and Cocktail Solution to Prevent Radial Artery Spasm during Coronary Angiography

BACKGROUND AND OBJECTIVES: A radial artery spasm is one of the most common complications of coronary angiography during a transradial, causing considerable patient discomfort, which sometimes disturbs the procedure. This study was designed to evaluate the effects of nicorandil in the prevention of a radial artery spasm during coronary angiography. SUBJECTS AND METHODS: This was a randomized study to compare 4 mg of nicorandil and a 10 mL cocktail solution performed in 100 patients. Vasospasms of the radial artery, which were expressed as stenosis of the vessel diameter with a transradial approach and radial artery patency by pulse oximetry analysis one month later, were examined. RESULTS: Reductions in the systolic and diastolic blood pressures after administration of the spasmolytic agents were 15.8+/-11.8/ 8.4+/-8.0 and 20.5+/-13.6/6.7+/-6.2 in the for nicorandil and cocktail groups, respectively. Nicorandil induced a lesser decrease in the systolic BP than the cocktail, but without statistical significance (p=0.07). Both vasodilating agents showed a significant radial artery vasodilation following their intra-arterial administration (p<0.001 for all). The diameter of the radial artery showed a significant decrease in both groups following catheterization (p<0.05 for all). There were no significant differences between the two groups in terms of radial artery spasms (46 vs. 58% in nicorandil and cocktail groups, respectively, p=0.709). CONCLUSION: Nicorandil, with vasodilatory effects due to a dual mechanism was as effective as the cocktail solution in the vasodilation of the radial artery.

Risk Stratification of Patients with Minor Troponin-I Elevation Unassociated with Acute Myocardial Infarction

BACKGROUND AND OBJECTIVES: Although cardiac troponin I is widely used as a marker for myocardial infarction (MI), minor elevations of cardiac troponin I are also observed in other clinical situations. The prognostic factors for patients with these clinical features are not well established. The aim of this study was to discover the predictors of mortality for the patients who had minor troponin elevations without acute MI. SUBJECTS AND METHODS: We enrolled consecutive 154 patients from the emergency department or inpatient units who had a peak troponin I level greater than the lower limit of detectability (0.04 ng/mL), and the level was also less than the suggestive value of MI (0.6 ng/mL). They were with chest pain or nonspecific symptoms of circulatory abnormality, but they lacked the traditional features of acute MI. The endpoint was defined as death from all causes. The Cox proportional hazard model was used to test the relationship between the clinical and biochemical variables and the outcomes. RESULTS: During the follow-up period of 7.9+/-7.3 months, mortality occurred in 15 patients. Age, the creatine kinase myocardial isoform (CK-MB) level and the C-reactive protein (CRP) level as continuous variables had significant correlations with the occurrence of death. After adjusting for any possible confounders in the multivariate model, these variables remained as independent predictors of mortality: age (HR 1.07, CI 1.02-1.14, p=0.012), CK-MB level (HR 1.61, CI 1.16-2.24, p=0.005), and CRP level (HR 1.01, CI 1.00-1.01, p=0.025). CONCLUSION: Integration of the CK-MB and CRP levels, as well as age, can be used for risk-stratification in the patients showing minor troponin I elevation for reasons other than acute MI.

A Case of Left Ventricular Thrombi in a Patient with Active Ulcerative Colitis and Normal Left Ventricular Systolic Function

Patients with ulcerative colitis(UC) can experience various extraintestinal complications in their course of disease, such as skin lesions, arthritis, cholangitis, ocular manifestation. Thrombosis may occur in 1.2~7.5% of patients, and it is known that the mortality is up to 25%. The sites of thrombosis are usually in deep veins, such as veins of lower extremities, pelvic venous plexus. But, on rare occasion, thrombosis can occur in cerebral veins, and result in cerebral infarct and hemorrhage. It is known that left ventricular(LV) thrombi can be developed when LV dysfunction exists, but it is extremely rare that LV thrombi occur in patients with normal LV function. So far, in patients with UC, there were a lot of cases complicated with venous thrombosis but arterial thrombosis was uncommon. Moreover, there was the only one case of LV thrombi with normal LV function in patient with UC. Accordingly, we report one case of LV thrombi with hemorrhagic cerebral infarct despite normal LV function in a patient with UC.

Investigations of the Air Volume for a Tracheal Tube Cuff in a Tracheal Models

PURPOSE: It is recommended that the cuff is inflated with about 10 ml air because cuff pressure is maintained from 25 cmH2O(=18.39 mmHg) to 40 cmH2O(=29.424 mmHg). This study is performed to evaluate the air volume of highvolume and low-pressure cuff during maintaining appropriate pressure. METHODS: The tracheal models are hexahedral structures were made of monomer Cast Polyamide with a whole diameter from 10 mm to 30 mm at 1mm interval each. They were 1/100 with accuracy. Intubation tube were Hi-LoT M (Mallinckrodt, Athlone, Ireland), high-volume low-pressure cuff tube. The diameter of tubes was from 5.0 mm to 8.0 mm at 0.5 mm interval each. Cuff pressure was measured with cuff pressure control (Tracoe(R), Mains, Germany). Inflated cuff volume is measured by plastic syringe (Becton-Dickson Korea, Seoul, Korea) in maintaining recommended cuff pressure. Volume measurements were twice by each different tester. RESULTS: There were considerable volume differences between each tube size and each model. The bigger trachea model diameter was, the more intracuff air volume was. There was the least volume difference in 5.5 mm intubation tube size (3.5~11.5 ml). There was the most difference in 7.5 mm intubation tube size (3.5~19.5 ml). Totally, the maximum air volume was 22.3 ml, the mininum air volume was 1.5 ml. The difference was 20.8 ml. CONCLUSION: The inflated volumes of cuff in proper cuff pressure were considerably different by the diameter sizes of tracheal models and tube sizes. Therefore, it will be more convenient and safe to use device for maintaining cuff pressure properly.