• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.487-499
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• 2000

Background : Acute lung injury is an hypoxic respiratory failure resulting from damage to the alveolar-capillary membrane, which can be developed by a variety of systemic inflammatory diseases. In this study the therapeutic effects of intra-tracheal pulmonary surfactant instillation was evaluated in the intratracheal endotoxin induced acute lung injury model of a rat. Methods : Twenty Sprague-Dawley rats were divided into 4 groups, and normal saline (2 ml/kg, for group 1) or LPS (5 mg/kg, for group 2, 3, and 4) was instilled into the trachea respectively. Either normal saline (2 ml/kg, for group 1 & 2, 30 min later) or bovine surfactant (15 mg/kg, 30 min later for group 3, 5 hr later for group 5) was instilled into the trachea. The therapeutic effect of intratracheal surfactant therapy was evaluated with one chamber body plethysmography (respiratory frequency, tidal volume and enhanced pause), ABGA, BAL fluid analysis (cell count with differential, protein concentration) and pathologic examination of the lung. Results : Intratracheal endotoxin instillation increased the respiration rate decreased the tidal volume and int creased the Penh in all group of rats. Intratracheal instillation of surfactant decreased Penh, increased arterial oxygen tension, decreased protein concentration of BAL fluid and decreased lung inflammation at both times of administration (30 minute and 5 hour after endotoxin instillation). Conclusion : Intratracheal instillation of surfactant can be a beneficial therapeutic modality as discovered in the acute lung injury model of rats induced by intratracheal LPS intillation. It deserves to be evaluated for treatment of human acute lung injury.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.415-425
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• 2001

Background : The correlation between the high resolution computed tomography(HRCT) emphysema score and the physiologic parameters including resting and exercise pulmonary function test was investigated in 14 patients($60.6{\pm}10.3$ years) with pulmonary emphysema. Methods : The patients underwent a HRCT, a resting pulmonary function test, and incremental exercise testing(cycle ergometer, 10 W/min). Computed tomography scans were obtained on a GE highlight at 10 mm intervals using 10 mm collimation, from the apex to the base after a full inspiration. The emphysema scores were determined by a CT program 'Density mask' outlining the areas with attenuation values less than -900 HU, indicating the emphysema areas, and providing an overall percentage of lung involvement by emphysema. Results : Among the resting PFT parameters, only the diffusing capacity(r=-0.75) and $PaO_2$ (r=-0.66) correlated with the emphysema score(p<0.05). Among the exercise test parameters, the emphysema score correlated significantly with the maximum power(r=-0.74), maximum oxygen consumption(r=-0.68), anaerobic threshold(V-slope method: r=-0.69), maximal $O_2$-pulse(r=-0.73), and the physiologic dead space ratio at the maximum workload(r=-0.80)(p<0.01). Conclusion: We could find that exercise testing parameters showed a much better correlation with the HRCT emphysema score, which is known to have a good correlation with the pathologic severity than the resting PIT parameters. Therefore it is suggested that exercise testing is superior to resting PIT for estimating in the estimation of the physiologic disturbance in emphysema patients.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.179-188
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• 2000

Background : The decision to institute mechanical ventilation for patients with COPD is very difficult. The accurate information regarding weaning success and long-term survival will improve communication with patients and family and enhance informed consent. The aims of this study are to describe outcomes and identify variables associated with survival for patients experiencing mechanical ventilation with an acute respiratory failure of COPD. Methods : The 53 cases of mechanical ventilation in the intensive care unit in the National Medical Center from 1989 to 1998 were included. Data were collected retrospectively from medical records. Weaning success rate and 3 month and 1 year survival rates were estimated. Factors associated with weaning success and survival were determined. Results : Weaning sucess was 55%. For success group with 29 cases, 3 months survival rate was 61% and 1 year survival rate 37%. APACHE II scores in weaning success group were significantly lower than those in the failure group. Factors such as age, sex, comorbid-illnes. previous steroid use, causes of respiratory failure, RVH or arrhythmia on EKG, serum albumin level, arterial blood pH, $PaO_2$, $PaCO_2$, $FEV_1$ duration of mechanical ventilation and steroid use during mechanical ventilation were not associated with weaning success. Only age and serum albumin level were associated with 3 month and 1 year survival. No COPD patients of age more than 75 years and serum albumin level less than 3g/dl had survived at 1 year after weaning success. Conclusion : While weaning success from mechanical ventilation can be predicted by APACHE II score in COPD patients, long-term outcomes of survivors may be influenced by nutritional status and age.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1105-1113
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• 1997

Background : Prone position improves oxygenation in some patients with ARDS. According to some authors, prone position can also improve the deteriorated hemodynamics induced by PEEP. But these respiratory and hemodynamic effects of prone position has not yet been fully established. Methods : Twentythree consequtive patients with ARDS(M : F= 11 : 12, $62.1{\pm}20.8yrs$) were the subjects for this study. ABGA, static compliance of the respiratory system, mean arterial pressure and pulse rate were obtained in supine position and at 5min, 0.5h and 2h of prone position. Positive respiratory response was defined as 20mmHg or more increase in $PaO_2/FIO_2$ within 2h of prone position. Early of late respiratory responses were defined if the positive response was observed within of after 3 day of ARDS onset, respectively. Positive hemodynamic response was defined as 10mmHg or more increase in mean arterial pressure at 5min of prone position. Results : Fifteen patients (65%) showed positive respiratory response. In the respiratory responders, $PaO_2$ was $69.8{\pm}17.6mmHg$ in supine position, $83.2{\pm}22.6mmHg$ in prone position 0.5h, $96.8{\pm}22.7mmHg$ in prone position 2h(p<0.001), and $PaO_2/FIO_2$ was $108{\pm}41mmHg$, $137{\pm}57mmHg$, $158{\pm}50mmHg$, respectively(p=0.001). Age, sex, cause of ARDS, supine $PaO_2$ and $PaO_2/FIO_2$ were not different between the respiratory responders and the nonresponders. The respiratory responders, however, showed higher mean arterial pressure than the nonresponders($91.1{\pm}13.1mmHg$ vs. $76.0{\pm}18.7mmHg$, p=0.035), and tendency of higher survival rate(9/15 vs. 2/8, p=0.074). Static compliance of the respiratory system was decreased in prone position 0.5h($28.4{\pm}7.9ml/cm$ $H_2O$ vs. $23.8{\pm}7.6ml/cm$ $H_2O$, p=0.007). The overall rate of early response(n=23) and late response(n=11) were similar(14/23 vs. 7/11, p>0.05). But patient without early response showed late response only in 25%(1/4), while patient with early response showed late response in 85.7%(6/7)(p=0.072). Five patients(22%) showed positive hemodynamic response, two of them being respiratory nonresponders. There were no differences in the baseline mean arterial pressure or the level of PEEP applied in supine between the hemodynamic responders and the hemodynamic nonresponders. Conclusions : Prone position either improved oxygenation or increased arterial pressure in significant proportion of patients with ARDS. And the respiratory response to prone position was thought to be determined in the early stage of ARDS.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.766-772
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• 2000

Background : Pressure rise time (PRT) is the time in which the ventilator aclieves the set airway pressure in pressure-targeted modes, such as pressure control ventilation (PCV). With varying PRT, in principle, the peak inspiratory flow rate of the ventilator also varies. And if PRT is set to a shorter duration, the effective duration of target pressure level would be prolonged, which in turn would increase inspiratory tidal volume(Vti) and mean airway pressure (Pmean). We also postulated that the increase in Vti with shortening of PRT may relate inversely to the patients' basal airway resistance. Methods : In 13 paralyzed patients on PCV (pressure control 18$\pm$9.5 cm $H_2O$ $FIO_2\;0.6\pm0.3$, PEEP 5$\pm$3 cm $H_2O$, f 20/min, I : E1 : 2) with Servo 300 (Siemens-Elema, Solna, Sweden) from various causes of respiratory failure, PRT of 10 %, 5 % and 0 % were randomly applied. At 30 min of each PRT trial, peak inspiratory flow (PIF, L/sec), Vti (ml), Pmean (cm $H_2O$) and ABGA were determined. Results : At PRT 10%, 5%, and 0%, PIF were 0.69$\pm$0.13, 0.77$\pm$0.19, 0.83$\pm$0.22, respectively (p<0.001). Vti were 425$\pm$94, 439$\pm$101, 456$\pm$106, respectively (p<0.001), and Pmean were 11.2$\pm$3.7, 12.0$\pm$3.7, 12.5$\pm$3.8, respectively (p<0.001). pH were 7.40$\pm$0.08, 7.40$\pm$0.92, 7.41$\pm$0.96, respectively (p=0.00) ; $PaCO_2$ (mm Hg) were 47.4$\pm$15.8, 47.2 $\pm$15.7, 44.6$\pm$16.2, respectively (p=0.004) ; $PAO_2-PaO_2$ (mm Hg) were 220$\pm$98, 224$\pm$95, 227$\pm$94, respectively (p=0.004) ; and $V_n/V_T$ as determined by ($PaCO_2-P_E-CO_2$)/$PaCO_2$ were 0.67$\pm$0.07, 0.67$\pm$0.08, 0.66$\pm$0.08, respectively (p=0.007). The correlation between airway resistance and change of Vti from PRT 10% to 0% were r= -0.243 (p=0.498). Conclusion : Shortening of pressure rise timee during PCV was associated with increased tidal volume, increased mean airway pressure and lower $PaCO_2$.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.367-376
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• 1996

Background : The diagnosis of emphysema during life is based on a combination of clinical, functional, and radiographic findings, but this combination is relatively insensitive and nonspecific. The development of rapid, high-resolution third and fourth generation CT scanners has enabled us to resolve pulmonary parenchymal abnormalities with great precision. We compared the chest HRCT findings to the pulmonary function test and arterial blood gas analysis in pulmonary emphysema patients to test the ability of HRCT to quantify the degree of pulmonary emphysema. Methods : From october 1994 to october 1995, the study group consisted of 20 subjects in whom HRCT of the thorax and pulmonary function studies had been obtained at St. Mary's hospital. The analysis was from scans at preselected anatomic levels and incorporated both lungs. On each HRCT slice the lung parenchyma was assessed for two aspects of emphysema: severity and extent. The five levels were graded and scored separately for the left and right lung giving a total of 10 lung fields. A combination of severity and extent gave the degree of emphysema. We compared the HRCT quantitation of emphysema, pulmonary function tests, ABGA, CBC, and patients characteristics(age, sex, height, weight, smoking amounts etc.) in 20 patients. Results : 1) There was a significant inverse correlation between HRCT scores for emphysema and percentage predicted values of DLco(r = -0.68, p < 0.05), DLco/VA(r = -0.49, p < 0.05), FEV1(r = -0.53, p < 0.05), and FVC(r = -0.47, p < 0.05). 2) There was a significant correlation between the HRCT scores and percentage predicted values of TLC(r = 0.50, p < 0.05), RV(r = 0.64, p < 0.05). 3) There was a significant inverse correlation between the HRCT scores and PaO2(r = -0.48, p < 0.05) and significant correlation with D(A-a)O2(r = -0.48, p < 0.05) but no significant correlation between the HRCT scores and PaCO2. 4) There was no significant correlation between the HRCT scores and age, sex, height, weight, smoking amounts in patients, hemoglobin, hematocrit, and wbc counts. Conclusion : High-Resolution CT provides a useful method for early detection and quantitating emphysema in life and correlates significantly with pulmonary function tests and arterial blood gas analysis.