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A national survey on the practice and outcomes of mechanical ventilation in Korean intensive care units.

Mechanical ventilation (MV) is an indispensable treatment in intensive care, but significantly increases medical costs (1). Moreover, MV, if prolonged, results in compromised health-related quality of life compared with those of a matched general population (2). Several reports have described MV use in intensive care units (ICU), including the characteristics of treated patients, the method of ventilator support and patient outcomes (3-6). However, there have been few reports from Asian countries.

Clinical settings relevant to MV care may vary from country to country as a consequence of variation in the prevalence of causes of respiratory failure. In addition, the practice and outcomes of MV in particular countries may be further modified by socio-cultural factors and by medical delivery systems (7). As in many Asian countries, Korea has few full-time critical care physicians or registered respiratory therapists and this may increase the probability of prolonged ICU stays.

The aims of this prospective survey were to identify the indications for MV in Korean ICUs, the clinical characteristics and outcomes of patients receiving MV, the ventilation protocols and the methods employed for weaning from MV. In addition, we compared some aspects of the findings with those from Western countries.


Study design

We conducted a prospective cohort study of consecutive adult patients who received MV for longer than 72 consecutive hours between May 1 and July 31, 2003, at 21 university hospital ICUs in Korea. The institutions represented major referral hospitals throughout the country. Before data collection the study protocol was reviewed and approved by the institutional review board of each hospital. Paediatric ICUs and coronary care units were excluded.

Physicians working in the enrolled ICUs

Resident physicians and interns assigned to ICU care were available at all times at all of the participating ICUs. Full-time critical care physicians, who by definition spend more than 50% of their working time in ICU care, were available at only four of the institutions (19%). These ICUs were also run on an open system like the other ICUs. At the other 17 institutions, the patient's attending physician supervised the ICU resident physicians.

Data collection

We collected data using a patient report form that surveyed patient demographics, indications for MV, type of artificial airway used, ventilator modes and settings, methods of weaning, other supportive measures including deep vein thrombosis (DVT) prevention and patient outcomes. The indication for MV was selected from a predefined list of causes of respiratory failure. Causes of acute respiratory failure (ARE) included postoperative state, acute respiratory distress syndrome (ARDS) (8), acute pulmonary oedema/congestive heart failure, aspiration, pneumonia, sepsis or septic shock (9), or trauma. Measured tidal volume (the mean value of five consecutive tidal breaths in a stable state) was expressed as the tidal volume per predicted body weight (10). The duration of MV was calculated as the time between the initiation of MV and the start of weaning that eventually resulted in success, as defined below. Significant cardiac arrhythmias were defined as any arrhythmia that required anti-arrhythmic agents or electrical cardioversion or was followed by a reduction in systolic blood pressure below 25% of baseline for longer than 30 minutes. Barotrauma was defined as pneumothorax, pneumomediastinum, pneumoperitoneum, subcutaneous emphysema on chest X-ray or physical examination that was thought related to MV Nosocomial pneumonia was diagnosed according to the Center for Disease Control definition (11). The attending physician chose the method of weaning. The final weaning method was the last mode that resulted in successful weaning, i.e. spontaneous unassisted breathing for >48 hours. The onset of the weaning process was dictated by the attending physician when he or she reduced the level of ventilatory support or started a spontaneous breathing trial for the purpose of weaning. The need for and timing of reintubation within 48 hours of extubation was recorded. Deconditioning of respiratory muscles was defined as weaning failure associated with paradoxical abdominal motion and/or use of accessory respiratory muscles without a preceding history of neuromuscular disease. All patients were followed up until hospital discharge.

Statistical analysis

Quantitative values are expressed as the mean [+ or -] SD. Categorical variables related to patient management and events occurring over the course of MV were coded as 0 (absence) or 1 (presence). Continuous variables (age, APACHE 11 score, [P.sub.a][O.sub.2]/[F.sub.i][O.sub.2] ratio, positive end-expiratory pressure and tidal volume) were coded as dummy variables if needed for comparison of all categories with the category related to lower mortality. The remaining continuous variables were dichotomised, using cutoff points based on published threshold values. For univariate analyses, frequencies were compared using the chi-square test and adjusted odds ratios, and 95% confidence intervals were calculated. Comparison between groups with respect to the reason for MV was made using a one-way analysis of variance for continuous variables. To estimate the simultaneous effects of multiple variables on ICU mortality, a multivariate analysis was performed using a conditional logistic regression model and an entry selection method to correct for co-linearity. The criterion for entering variables tested in the model was P <0.10. Statistical analyses were performed using the SPSS version 12.0 package (SPSS Inc, Chicago, IL, USA). A P value <0.05 was considered statistically significant.


Population characteristics

Over the three-month study period, 519 patients were enrolled. All patients were followed for 28 days. The mean patient age was 62.9[+ or -]15.9 years. Pre-existing medical disease was present in 372 patients and included neoplasm (85), chronic renal disease (35), chronic liver disease (33) and diabetes mellitus (17). The mean APACHE II score was 25.4 in ARDS patients and 17.8 in postoperative patients. The mean length of stay in the ICU was 17.4 days for ARDS patients and 15.3 days for postoperative patients.

Indications for MV

The reasons for MV in patients are listed in Table 1. The most common reason was ARE, which occurred in 73.4% of patients. The most common cause of ARE was pneumonia, whereas the most common cause of acute-on-chronic respiratory failure (ACRE) was tuberculous lung disease.


MV was initially delivered via an orotracheal tube in 394 patients (90.4%), tracheostomy in 16 patients (3.7%) and nasotracheal tube in six patients (1.4%). Non-invasive positive pressure ventilation (NPPV) was used as the first MV method in 20 patients (4.6%), which was practised in only five ICUs. Tracheostomy was performed at 15.3[+ or -]7.3 days (mean [+ or -] SD) after initiation of MV

Mode and setting of MV

Initial ventilator modes were volume control ventilation in 43.0% of patients and pressure control ventilation in 28.3% of patients. Volume control ventilation was the most common ventilation mode in ARDS (45.3%) and postoperative patients (36.8%). NPPV was used in only 11.9% of ACRE patients. Mean tidal volume for all patients was 8.0 ml/kg of predicted body weight. Mean tidal volume for ARDS patients was 7.6 ml/kg of predicted body weight and mean positive end-expiratory pressure (PEEP) was 9.4 cm [H.sub.2]O.

Use of sedatives and neuromuscular blockers

Sedatives of any type were administered in 412 patients (79.4%) and neuromuscular blockers were administered in 218 patients (42.0%).

Complications of MV

Complications of MV were nosocomial pneumonia in 53 (10.2%), clinically significant arrhythmias in six (1.2%), barotrauma in 15 (2.9%), deconditioning of respiratory muscle in four (0.8%) and tracheal stenosis in one (0.2%).

Weaning from MV

The most common initial weaning method was pressure support ventilation (PSV) (99 patients; 29.9%), whereas the most common final weaning method was spontaneous breathing using a T -piece (Table 3). Other weaning methods included the simultaneous use of volume-controlled synchronised intermittent mechanical ventilation (SIMV) plus PSV in 78 patients (23.6%), T -piece in 61 patients (18.4%), continuous positive airway pressure in 56 patients (16.9%), volume-controlled SIMV in 26 patients (7.9%) and NPPV in six patients (1.8%). Final weaning methods included T-piece in 136 patients (45.3%), PSV in 63 patients (21.0%), continuous positive airway pressure in 41 patients (13.7%), volume-controlled SIMV plus PSV in 32 patients (10.7%), volume-controlled SIMV in 11 patients (3.7%), NPPV in nine patients (3.0%) and unplanned extubation in six patients (2.0%). Thirty-two patients required reintubation within 48 hours of extubation. The interval between extubation and reintubation was 15.9[+ or -]13.3 hours.

Ancillary treatments during MV

Prophylaxis against DVT and stress ulcers were applied in 180 (34.7%) and 446 (85.9%) patients, respectively. Time to resumption of enteral feeding of any amount was 3.3[+ or -]3.3 days.

Weaning and survival outcomes

The total duration of MV, time spent for weaning and the length of ICU stay as a function of the reason for MV initiation are shown in Table 4. During the study period, 238 patients (46.7% of reported cases for outcome) were successfully weaned. The weaning success rate was 47% in ARDS patients and 81.1% in postoperative patients (Table 5). Twenty-eight day ICU mortality rates were 46.2% in ARDS patients, 43.3% in non-ARDS sepsis patients and 22.2% in postoperative patients (Table 5). The mortality of patients with tuberculous lung disease was 52.4%. At 28 days, 174 patients died in the ICU (34.6%), 33 (6.6%) were discharged hopeless and eight (1.6%) were discharged against medical advice. Two hundred and twenty-four patients (44.5%) were transferred to general wards, 37 (7.4%) were transferred to another hospital and 35 (7.0%) remained in the ICU. The causes of death were multiorgan failure in 58 (31.4%), septic shock in 52 (28.1%), respiratory failure in 37 (20.0%), heart failure in 14 (7.6%) and hepatic failure in seven (3.8%).

Effect of presence of full-time critical care physicians on ventilatory management in patients with ARDS

In addition to 53 patients with the diagnosis on presentation, ARDS developed in 48 other patients during the 28 days. Thirty-three of the total patients with ARDS (101) were managed in ICUs with full-time critical care physicians. These patients received a higher PEEP level (10.4 vs. 7.1 cm[H.sub.2]O, P=0.001) during the first 72 hours compared with ARDS patients in ICUs without such full-time critical care physicians (Table 6). Other ancillary treatments during MV were more applied in ICUs attended by full-time critical care physicians (P <0.05): DVT prophylaxis (48.5% vs. 14.5%), prone positioning (24.2% vs. 8.8%), nitric oxide inhalation (30.3% vs. 0%) and alveolar recruitment manoeuvre (54.5% vs. 11.8%). However, crude mortality rates (57.6% vs. 49.3%) were not different between the two groups of patients.

MV prognostic factors for patient mortality

Univariate analysis showed that factors associated with mortality included APACHE 11 scores greater than 20; acute-on-CRF, neuromuscular disease and ARDS as reasons for ventilatory support; neoplasms, chronic renal diseases, postoperative care; a respiratory rate >30 /min at 72 hours of ventilatory support, parenteral nutrition and the absence of DVT prevention (Table 7). Cox proportional analysis showed that independent factors associated with mortality included the APACHE II score, indications for mechanical ventilation, and enteral feeding.


Population characteristics and indications for MV

Patients in Korean adult ICUs were similar to comparable MV patients in Western countries with respect to age, but the APACHE II scores were slightly higher (8,12,13). Primary indications for MV in Korea are similar to Western ICUs (13). However, tuberculous lung disease was the most frequent aetiology of MV in the group of ACRE patients. As tuberculosis is still prevalent in Korea (incidence 73.2/100,000 in 2006; statistics of the Korean Health and Welfare Bureau) (14) compared with Western countries (4.6/100,000 in 2006; USA) (15), our result suggest that tuberculous lung disease may be an important cause of ACRF in Asian countries.

Ventilatory strategy

The selection of initial modes of mechanical ventilation varied considerably among participating ICUs. Almost half the patients were cared for in the volume-controlled mode and 20% by volume-controlled SIMV These are similar values to those in previous reports (3,13). Few ICUs adopted NPPV as an initial mode of ventilation in patients with ACRE This rate is much lower than in Western Countries (16). This could be attributable to relatively short history of NPPV in our country, low nurse-to-patient ratio and inadequate reimbursement from the government compared with invasive ventilation.

In contrast to the diversity in preferred ventilation modes, the magnitude of tidal volume was consistent among the ICUs investigated. The mean PEEP level was highest in ARDS patients compared with other causes of respiratory failure, suggesting that physicians were aware of lung-protecting strategies in MV (17) or that their oxygenation was worse prompting higher PEEP levels.

Use of sedative and neuromuscular blockers

The use of sedatives (79.4% of patients) was higher than reported in an earlier study (68%) by the International Mechanical Ventilation Study Group (18). An excessive use of sedatives can lengthen ventilation days required, ICU stays and morbidity (18,19). Together with the relatively longer duration of the MV in our result, this rate of sedative use in Korean institutions requires attention from physicians and efforts to reduce it through daily interruption as now internationally recommended (20).

Effect of full-time ventilatory management in patients with ARDS and preventative measures for DVT and stress ulcer prophylaxis

ICUs managed by critical care physicians showed better compliance with current guidelines in critical care medicine, as illustrated by the higher rates of use of many preventative measures for patients receiving MV. However, the total duration of MV was not different between institutions with full-time critical care physician and institutions without them. Differences among institutions, e.g. patient severity, could have masked the influence of critical care physicians. To discern the impact of the presence of critical care physician, a controlled randomised prospective study would be necessary.

Patients on MV are vulnerable to a few important complications including DVT (21) and stress ulcers (22). To our surprise, DVT prophylaxis was performed in only 34.7% of ventilated subjects. Weak evidence for this may be the lower level of obesity in the general population in Korea. The average body mass index in Korean adults is 23.3 to 24.1 kg/[m.sup.2] as compared with 27.9 kg/[m.sup.2] in the USA (23,24).

Weaning from MV

The most common initial weaning method was PSV and the most common final weaning method was spontaneous breathing using a T-piece. These results differ from those of a European study in which the combination of SIMV and PSV was the most common weaning methods (14). As recent studies indicate better results with spontaneous breathing using a T-piece or PSV (25-27), Korean weaning methods largely conform to current evidence.

Outcome of MV

Incidences of ventilator-associated pneumonia and barotrauma were similar to those in Western countries (28,29). The mean duration of MV was 10.8 days in general, around 10 to 13 days for patients with ARE and 11.2 days for patients with ACRF, which was slightly longer than previously reported. The observed 28-day ICU mortality (34.5%) was comparable to that in a study in Western countries (29). However, the crude mortality of ARDS patients (46.2%) appeared to be higher than that in a study conducted in Western countries (8). The difference in ARDS mortality may be due to differences in the severity of the general medical condition of our patients as reflected in a higher APACHE 11 score (25.4 vs. 19.08), differences in ICU organisation in terms of nurse-to-bed ratio and the limited availability of critical care physicians and respiratory therapists.

Survival of respiratory failure patients depends not only on factors present when initiating MV but also on the development of complications, changes in monitored variables and patient management during the course of MV (4). In multivariate analyses the factors independently associated with decreased survival were a higher APACHE II score and ACRE as a reason for mechanical ventilation. The only factor independently associated with decreased mortality was enteral feeding. This finding is not consistent with the results of other studies. For example, in one study both acute lung injury and sepsis as causes of MV were independently associated with an increased hospital mortality rate (30).

The present study has limitations that are inherent with studies using a questionnaire. We were not able to identify the final outcome in 16 registered patients. In addition, we did not survey the development of organ failure, which is known to be an important prognostic factor in critically ill patients.


Most demographic variables, disease severity and mortality of Korean MV patients were similar to those of patients in Western countries. However, tuberculous lung disease was an important aetiology of acute-on-chronic respiratory failure patients requiring mechanical ventilation in Korea. Noninvasive positive pressure ventilation was not as frequently used in the Korean ICUs as in Western countries (31). Our data suggest that the presence of full-time critical care physicians on site may facilitate adoption of recommended guidelines for MV use in Korea.


We thank all the physicians of the Korean Study Group on Respiratory Failure who contributed to the databases used in this study. We also thank Dr Sang Bum Hong and Dr Bum Jin Oh for statistical analysis and acknowledge the editorial assistance provided by Dr Ross Freebairn.

Address for reprints: Dr Y. Koh, Asan Medical Center, Department of Pulmonary and Critical Care Medicine, University of Ulsan College of Medicine, Seoul 138-600, Korea.

Accepted for publication on October 10, 2008


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(22.) Cook D, Guyatt G, Marshall J, Leasa D, Fuller H, Hall R et al. A comparison of sucralfate and ranitidine for the prevention of upper gastrointestinal bleeding in patients requiring mechanical ventilation. New Engl J Med 1998; 338:791-797.

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(25.) Brochard L, Rauss A, Benito S, Conti G, Mancebo J, Rekik N et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation. Am J Respir Crit Care Med 1994; 150:896-903.

(26.) Esteban A, Frutos F, Tobin MJ, Alia I, Solsona JF, Valverdu I et al. A comparison of four methods of weaning patients from mechanical ventilation. Spanish lung failure collaborative group. New Engl J Med 1995; 332:345-350.

(27.) Ely EW, Baker AM, Dunagan DP, Burke HL, Smith AC, Kelly PT et al. Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously. New Engl J Med 1996; 335:1864-1869.

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(29.) Anzueto A, Frutos-Vivar F, Esteban A, Alia I, Brochard L, Stewart T et al. Incidence, risk factors and outcome of barotrauma in mechanically ventilated patients. Intensive Care Med 2004; 30:612-619.

(30.) Epstein SK, Vuong V Lack of influence of gender on outcomes of mechanically ventilated medical ICU patients. Chest 1999; 116:732-739.

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Y. KOH *, C. M. LIM [dagger], S. O. KOH ([double dagger]), J.-J. AHN ([section]), Y. S. KIM **, B. H. JUNG ([dagger])([ dagger]), J. H. CHO ([double dagger])([double dagger]), J. H. LEE ([section])([section]), M. G. LEE ***, K. S. JUNG ([dagger])([dagger])([dagger]), O. J. KWON ([double dagger])([double dagger]) ([double dagger]), Y. J. LEE ([section])([section])([section])

Asan Medical Center and collaborating hospitals, Department of Pulmonary and Critical Care Medicine, University of Ulsan College of Medicine, Seoul Korea

* M.D., Ph.D., F.C.C.M., Professor, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine.

([dagger]) M.D., F.C.C.M., Professor, Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine.

([double dagger]) M.D., Ph.D., Professor, Department of Anesthesiology and Critical Care Medicine, Yonsei University College of Medicine.

([section]) M.D., Associate Professor, Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine.

** M.D., Associate Professor, Department of Pulmonary and Critical Care Medicine, Pusan University Hospital, Pusan National University College of Medicine, Pusan.

([dagger])([dagger]) M.D., Associate Professor, Department of Pulmonary and Critical Care Medicine, Gangneung Asan Hospital, University of Ulsan College of Medicine, Kangneung.

([double dagger])([double dagger]) M.D., Associate Professor, Department of Pulmonary and Critical Care Medicine, Inha University Hospital, Inha University College of Medicine, Incheon.

([section])([section]) M.D., Associate Professor, Department of Pulmonary and Critical Care Medicine, Ewha Womans University Mocdong Hospital, Ewha Womans University School of Medicine.

*** M.D., Professor, Department of Pulmonary and Critical Care Medicine, Chuncheon Sacred Heart Hospital, Hallym University School of Medicine, Chuncheon.

([dagger])([dagger])([dagger]) M.D., Professor, Department of Pulmonary, Allergy and Critical Care Medicine, Hallym University Sacred Heart Hospital, Hallym University School of Medicine.

([double dagger])([double dagger])([double dagger]) M.D., Professor, Department of Pulmonary and Critical Care Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine.

([section])([section])([section]) M.D., Professor, Department of Anesthesiology and Critical Care Medicine, Ajou University Hospital, Ajou University School of Medicine, Suwon.

Characteristics of the subjects with more than 72 hours of
mechanical ventilation

Characteristics                   No. (%) of patients
                                  mechanically ventilated

Age, mean (SD)                    62.9 (15.9) [66 {54-74}
[median {IQR}], y

Gender, female                    169 (32.6)

APACHE II score                   22.4 (8.1) [22 {17-28}]

Reason for the initiation of
mechanical ventilation

  ACRF                            59 (11.4)
  COPD                            19 (3.7)
  Asthma                          4 (0.8)
  Bronchiectasis                  5 (1.0)
  Tuberculosis destroyed lung     22 (4.2)
  Interstitial pneumonia          9 (1.7)
  Coma                            50 (9.6)
  Neuromuscular disease           29 (5.6)
  ARF                             381 (73.4)
  ARDS                            53 (10.2)
  Post-operation                  38 (7.3)
  Congestive heart failure        60 (11.6)
  Aspiration                      29 (5.6)
  Pneumonia                       118 (22.7)
  Sepsis/septic shock             69 (13.3)
  Trauma                          7 (1.4)
  Others                          7 (1.4)

IQR = interquartile range, APACHE
11 score = Acute Physiology score,
ACRF = acute-on-chronic respiratory failure,
COPD = chronic obstructive pulmonary
disease, ARF = acute respiratory failure,
ARDS = acute respiratory distress syndrome.


Initial ventilator modes and at 72 hours after ventilatory
support according to the reasons for mechanical ventilation

                  Total (n=519)     ARDS (53)         ACRF (59)


VCV               223 (43%)         24 (45%)          32 (54%)
PCV               147 (28%)         17 (32%)          13 (22%)
SIMV              34 (7%)           2 (4%)            2 (3%)
SIMV+PSV          67 (13%)          6 (11%)           3 (5%)
PSV               21 (4%)           3 (6%)            2 (3%)
NPPV              20 (4%)           1 (2%)            7 (12%)
Others            7 (1%)            0                 0

72 hours later

VCV               153 (30%)         16 (30%)          23 (39%)
PCV               143 (28%)         19 (36%)          14 (24%)
SIMV              40 (8%)           4 (8%)            7 (12%)
SIMV + PSV        96 (18%)          9 (17%)           1 (2%)
PSV               63 (12%)          4 (8%)            6 (10%)
NPPV              9 (2%)            0                 5 (8%)
Others            15 (3%)           1 (2%)            3 (5%)

                  Pneumonia (118)   Sepsis (69)       operation (38)


VCV               60 (51%)          19 (28%)          14 (37%)
PCV               26 (22%)          27 (39%)          6 (16%)
SIMV              9 (8%)            4 (6%)            6 (16%)
SIMV+PSV          9 (8%)            14 (20%)          10 (26%)
PSV               4 (3%)            4 (6%)            2 (5%)
NPPV              8 (7%)            1 (1%)            0
Others            2 (2%)            0                 0

72 hours later

VCV               44 (37%)          17 (25%)          5 (13%)
PCV               24 (20%)          26 (38%)          8 (21%)
SIMV              11 (9%)           3 (4%)            2 (5%)
SIMV + PSV        22 (19%)          15 (22%)          15 (39%)
PSV               11 (9%)           8 (12%)           7 (18%)
NPPV              2 (2%)            0                 0
Others            4 (3%)            0                 1 (3%)

ARDS = acute respiratory distress syndrome, ACRF = acute-on-chronic
respiratory failure, PSV = pressure support ventilation,
SIMV = synchronized intermittent mandatory ventilation,
NPVV = non-invasive positive pressure ventilation, PCV = pressure
control ventilation, VCV = volume control ventilation.


Initial and final weaning methods according to the reasons for
mechanical ventilation

                        Total      ARDS      ACRF

Initial weaning method  331        31        33

PSV                     99 (30%)   7 (23%)   10 (30%)
SIMV                    26 (8%)    2 (7%)    4 (12%)
SIMV + PSV              78 (24%)   10 (32%)  8 (24%)
CPAP                    56 (17%)   3 (10%)   1 (3%)
T-piece trial           61 (18%)   9 (29%)   7 (21%)
NPPV                    6 (2%)     0         3 (9%)
Others                  5 (2%)     0         0

Final weaning method    300        28        30

PSV                     63 (21%)   5 (18%)   5 (17%)
SIMV                    11 (4%)    1 (4%)    2 (7%)
SIMV + PSV              32 (11%)   3 (11%)   2 (7%)
CPAP                    41 (14%)   3 (11%)   1 (3%)
T-piece trial           136 (45%)  15 (54%)  14 (47%)
NPPV                    9 (3%)     0         4 (13%)
Unplanned extubation    6 (2%)     1 (4%)    2 (7%)
Others                  2 (1%)     0         0

                        Pneumonia  Sepsis    Post-operation

Initial weaning method  71         47        34

PSV                     19 (27%)   14 (30%)  10 (29%)
SIMV                    11 (16%)   3 (6%)    1 (3%)
SIMV + PSV              16 (23%)   3 (6%)    10 (29%)
CPAP                    7 (10%)    17 (36%)  10 (29%)
T-piece trial           14 (20%)   9 (19%)   3 (9%)
NPPV                    2 (3%)     0         0
Others                  2 (3%)     1 (2%)    0

Final weaning method    61         43        33

PSV                     10 (16%)   7 (16%)   10 (29%)
SIMV                    4 (7%)     0         1 (3%)
SIMV + PSV              11 (18%)   2 (5%)    1 (3%)
CPAP                    2 (3%)     9 (21%)   10 (30%)
T-piece trial           29 (48%)   23 (54%)  11 (33%)
NPPV                    3 (5%)     0         0
Unplanned extubation    2 (3%)     1 (2%)    0
Others                  0          1 (2%)    0

ARDS = acute respiratory distress syndrome, ACRF = acute-on-chronic
respiratory failure, PSV = pressure support ventilation,
SIMV = synchronised intermittent mandatory ventilation, CPAP
= continuous positive airway pressure, NPPV = non-invasive positive
pressure ventilation.


Duration of total mechanical ventilation, duration of weaning,
and length of ICU stay according to the reason for initiating
mechanical ventilation

                     Total (n=519)   ARDS (53)      ACRF (59)

Gender, female (%)   33%             24%            20%

Age (y)              62.9[+ or -]    64.3[+ or -]   65.8[+ or -]
                      15.9            13.3           16.0

APACHE score         22.2[+ or -]    25.4[+ or -]   19.7[+ or -]
                      8.3             7.9            7.3

Length of stay       12.9[+ or -]    13.5[+ or -]   13.3[+ or -]
in ICU (d)            7.5             7.1            7.9

Total ventilation    10.8[+ or -]    12.7[+ or -]   11.2[+ or -]
time (d)              7.0             8.0            7.5

Duration of          4.0[+ or -]     4.1[+ or -]    3.5[+ or -]
weaning (d)           5.3             5.7            3.7

                     Pneumonia       Sepsis (69)    Post-operation
                       (118)                           (38)

Gender, female (%)   27%              33%              39%

Age (y)              66.3[+ or -]     63.8[+ or -]  54.3[+ or -]
                      14.5             13.5          17.7

APACHE score         21.9[+ or -]     23.8[+ or -]  17.1[+ or -]
                      7.5              8.2           6.9

Length of stay       13.7[+ or -]     11.9[+ or -]  13.1[+ or -]
in ICU (d)            7.9              7.3              7.4

Total ventilation    11.5[+ or -]     10.1[+ or -]  9.7[+ or -]
time (d)              6.7              6.5           6.2

Duration of          3.9[+ or -]      3.9[+ or -]   3.8[+ or -]
weaning  (d)          5.8              4.6           6.5

ARDS = acute respiratory distress syndrome, ACRF = acute-on-chronic
respiratory failure, ICU = intensive care unit.


Weaning success rate and 28 day ICU mortality in patients ventilated
more than 72 hours

                       Total           ARDS          ACRF

Weaning success rate   238/473 (50%)   21/45(47%)    21/54(39%)

Mortality at 28 days   207/503 (41%)   24/52(46%)    29/56(52%)

                       Pneumonia       Sepsis        Post-operation

Weaning success rate   48/112 (43%)    35/63(56%)    30/37(81%)

Mortality at 28 days   51/115 (44%)    29/67(43%)    8/36(22%)

ARDS = acute respiratory distress syndrome, ACRF = acute-on-chronic
respiratory failure.


Effect of full-time intensivist on ventilatory
management in patients with ARDS

                                  With intensivist (n=33)

Age (y)                           61.8[+ or -]13.8
APACHE score                      25.5[+ or -]7.2
[P.sub.a][O.sub.2]/Fi[O.sub.2]    133.5[+ or -]94.5
Tidal volume at 72 hours (ml)     438[+ or -]82
PEEP at 72 hours (cm[H.sub.2]O)   10.4[+ or -]4.1
Tidal volume at weaning (ml)      488[+ or -]115
PEEP at weaning (cm[H.sub.2]O)    8.7[+ or -]5.1
Duration of tracheostomy (d)      11.6[+ or -]6.9
Total ventilation time (d)        11.9[+ or -]7.5
Duration of weaning (h)           105.7[+ or -]96.1
DVT prophylaxis (%)               48.5
Arterial-line insertion (%)       84.8
iNO therapy (%)                   30.3
Prone positioning (%)             24.2
Alveolar recruitment              54.5
  manoeuvre (%)

                                  Without intensivist (n=68)

Age (y)                           63.5[+ or -]15.2
APACHE score                      24.4[+ or -]7.9
[P.sub.a][O.sub.2]/Fi[O.sub.2]    131.1[+ or -]77.2
Tidal volume at 72 hours (ml)     486[+ or -]107
PEEP at 72 hours (cm[H.sub.2]O)   7.1[+ or -]4.6
Tidal volume at weaning (ml)      472[+ or -]106
PEEP at weaning (cm[H.sub.2]O)    4.9[+ or -]3.8
Duration of tracheostomy (d)      17.1[+ or -]7.5
Total ventilation time (d)        11.6[+ or -]7.3
Duration of weaning (h)           76.9[+ or -]128.0
DVT prophylaxis (%)               14.5
Arterial-line insertion (%)       17.4
iNO therapy (%)                   0
Prone positioning (%)             8.8
Alveolar recruitment              11.8
  manoeuvre (%)

                                  P value

Age (y)                           NS
APACHE score                      NS
[P.sub.a][O.sub.2]/Fi[O.sub.2]    NS
Tidal volume at 72 hours (ml)     0.026
PEEP at 72 hours (cm[H.sub.2]O)   0.001
Tidal volume at weaning (ml)      NS
PEEP at weaning (cm[H.sub.2]O)    0.006
Duration of tracheostomy (d)      NS
Total ventilation time (d)        NS
Duration of weaning (h)           NS
DVT prophylaxis (%)               0.001
Arterial-line insertion (%)       0.001
iNO therapy (%)                   0.001
Prone positioning (%)             0.035
Alveolar recruitment              0.001
  manoeuvre (%)

APACHE = Acute Physiology and Chronic Health Evaluation,
PEEP = positive end-expiratory pressure, DVT = deep vein
thrombosis, iNO = nitric oxide inhalation.


Univariate and multivariate analysis of factors associated with
intensive care unit mortality in ventilated patients

                           Mortality, % (95% CI)   Univariate analysis
                                                   Odds ratio (95% CI)

                              Factors present at initiation of
                                  mechanical ventilation

  0~9                      13.6(3~35)              1.00
  10~19                    33.6 (25~39)            3.20 (0.90-11.31)
  >20                      48.0 (43~55)            5.85 (1.69-20.22)

Reason for initiation of mechanical ventilation
  ACRF                     51.8 (38.3-65.3)        1.62 (0.93-2.83)
  Coma                     47.9 (33.3-62.6)        1.36 (0.75-2.46)
  Neuromuscular disease    13.8 (0.4-27.1)         0.21 (0.07-0.62)
  ARF                      40.8 (35.8-45.8)        0.95 (0.63-1.42)

Underlying cause
  Neoplasm                 55.4 (44.5-66.3)        2.01 (1.23-3.30)
  Chronic liver disease    45.5 (27.5-63.4)        1.16 (0.57-2.38)
  Chronic renal disease    58.8 (41.4-76.3)        2.11 (1.03-4.32)
  Complicated diabetes     23.5 (1.0-46.0)         0.41 (0.13-1.27)
  Chronic lung disease     44.9 (32.9-57.0)        1.15 (0.68-1.95)
  Acute abdominal process  42.1 (17.7-66.6)        1.00 (0.39-2.54)
  Heart failure            30.8 (11.8-49.8)        0.59 (0.25-1.39)
  Peripheral vascular
    disease                28.6 (-16.6-73.7)       0.54 (0.10-2.84)
  Autoimmune disease       66.7 (-76.8-210.1)      2.77 (0.25-30.81)
  Neuromuscular disorder   30.4 (10.1-50.8)        0.58 (0.23-1.45)
  Post-operation           20.7 (5.0-36.4)         0.33 (0.13-0.84)
  Trauma                   17.6 (-2.6-37.9)        0.28 (0.08-0.99)
  ARDS                     52.0 (42.1-61.8)        1.74 (1.12-2.69)

                              Factors related to patient management

Enteral feeding            34.1 (29.2-39.0)        0.35 (0.23-0.52)
Prophylaxis of DVT         32.8 (25.7-39.8)        0.58 (0.39-0.84)
Use of neuromuscular
  blockers                 41.8 (35.1-48.5)        1.03 (0.72-1.47)
  prophylaxis              41.6 (37.0-46.3)        1.10 (0.65-1.86)
Bronchodilator             38.3 (32.0-44.6)        0.79 (0.55-1.13)
Steroid use                41.0 (32.6-49.5)        0.99 (0.66-1.47)
Respiratory rate
  0~19                     30.6 (24.2-36.9)        1.00
  20~29                    47.6 (41.5-53.6)        2.06 (1.41-3.02)
  >30                      63.0 (43.5-82.4)        3.86 (1.67-8.90)

                           Univariate      Multivariate analysis

                           P value      Odds ratio          P value
                                         (95% CI)

  0~9                      0.001        1.00                0.017
  10~19                    0.071        1.79 (0.34-9.54)    0.493
  >20                      0.005        3.70 (0.74-18.47)   0.110

Reason for initiation of mechanical ventilation
  ACRF                     0.088        2.47 (1.15-5.35)    0.021
  Coma                     0.318
  Neuromuscular disease    0.005
  ARF                      0.795

Underlying cause

  Neoplasm                 0.006
  Chronic liver disease    0.687
  Chronic renal disease    0.042
  Complicated diabetes     0.122
  Chronic lung disease     0.604
  Acute abdominal process  0.997
  Heart failure            0.227
  Peripheral vascular
    disease                0.469
  Autoimmune disease       0.408
  Neuromuscular disorder   0.245
  Post-operation           0.019
  Trauma                   0.049
  ARDS                     0.014

Enteral feeding            <0.001       0.47 (0.29-0.76)    0.002
Prophylaxis of DVT         0.005
Use of neuromuscular
  blockers                 0.881
  prophylaxis              0.733
Bronchodilator             0.197
Steroid use                0.940
Respiratory rate
  0~19                     <0.001
  20~29                    <0.001
  >30                      0.002

CI = confidence interval, APACHE = Acute Physiology and Chronic
Health Evaluation, ARF = acute respiratory failure, AIDS = acquired
immune deficiency syndrome. DVT = deep vein thrombosis
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Article Details
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Author:Koh, Y.; Lim, C.M.; Koh, S.O.; Ahn, J.-J.; Kim, Y.S.; Jung, B.H.; Cho, J.H.; Lee, J.H.; Lee, M.G.; J
Publication:Anaesthesia and Intensive Care
Article Type:Clinical report
Geographic Code:9SOUT
Date:Mar 1, 2009
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