1453
Esteban, Anzueto, Alía, et al.: International Utilization Review on Mechanical Ventilation TABLE 3 AIRWAY USED IN VENTILATED PATIENTS ACCORDING TO COUNTRY Chile
Portugal
Uruguay
546 (73%)
USA/Canada
351 (79%)
115 (75%)
85 (70%)
52 (87%)
44 (65%)
36 (82%)
1,229 (75%)
Orotrach
517 (95%)
338 (96%)
115 (100%)
85 (100%)
51 (98%)
37 (84%)
36 (100%)
1,179 (96%)
Nasotrach
29 (5%)
13 (4%)
—
1 (2%)
7 (16%)
—
50 (4%)
Tracheostomy
192 (26%)
87 (20%)
34 (22%)
33 (27%)
8 (13%)
24 (35%)
8 (18%)
386 (24%)
5 (1%)
4 (1%)
1 (1%)
4 (3%)
—
—
—
14 (1%)
Intubation
Facial mask
Spain
Argentina
Brazil
—
Physician Preferences
A total of 2,226 physicians completed the questionnaire. A/C was the preferred mode of 62%, but that percentage varied considerably among countries (Table 7). In general, the mode listed by physicians corresponded with the mode most frequently employed in a given country. The preferred methods for weaning were PS (34% of the respondents) and SIMV with or without PS (35% of the respondents).
DISCUSSION The primary indications for mechanical ventilation were remarkably similar across countries. In contrast, the selection of modes of mechanical ventilation and methods of weaning varied considerably from country to country. Of patients in the ICUs, an average of 39% were receiving mechanical ventilation, but the proportion varied considerably among countries. The variation may reflect differences in type of ICU, admission and discharge policies, and patient profiles. The ICUs were not selected randomly, and the identification of ICUs and also their voluntary participation may have produced a selection bias. It cannot be assumed that the studied ICUs are necessarily representative of a given country, and observed differences among countries must be interpreted with caution. The percentage of patients receiving mechanical ventilation would have been higher if patients receiving ventilation for a brief period of time had been enrolled in the study. When planning the study, we deliberately selected 11:00 A.M. to minimize the influence of patients receiving brief ventilator support after surgery on the overall study population. This aspect of study design may explain why postoperative patients constituted less than 10% of the total study population and that patients receiving short-term ventilator support (less than 24 h) accounted for only 18% of the study population. The average age of our patients was high: 25% of the ventilated patients were older than 71 yr of age. This finding was not confined to countries where the average age of the population is high. In recent published series of ventilator-supported patients, the mean age has been around 60 yr (2, 4, 7–10). The data suggest that advanced age did not preclude patients from being admitted to the ICU; indeed, it has been demonstrated
Total
that the prognosis in elderly patients admitted to an ICU (11) or receiving mechanical ventilation (12) does not depend exclusively on age, but rather on the severity of the acute illness and the functional status. Men accounted for 60% of the patients receiving mechanical ventilation. Other investigators have also reported a higher proportion of men among patients receiving mechanical ventilation (2, 4, 7, 9, 10) or admitted to an ICU (13). Acute respiratory failure was the most frequent indication for mechanical ventilation, accounting for two thirds of patients in four countries and for half the patients in the other three countries. Among the subgroups of acute respiratory failure, ARDS accounted for 12% of ventilated patients. Because of the complex pulmonary pathophysiology in patients with ARDS and the many new modes of mechanical ventilation developed to deal with this problem, attempts have been made to obtain more precise information on the incidence of acute lung injury and ARDS. The reported incidence of ARDS ranges from 1.5 to 8 cases per 100,000 inhabitants (14–16). Of all 4,153 patients in ICUs on the day of our study, only 3% had ARDS—similar to the rates of 2 to 3% in two recent retrospective studies (17, 18). Patients with COPD accounted for 13% of all patients receiving mechanical ventilation, being the most common indication in North America and greater than any subcategory of acute respiratory failure in all countries. We cannot calculate the proportion of patients with COPD receiving mechanical ventilation since we do not know the total number admitted to ICUs at the time of the study. In control groups of recent prospective studies of noninvasive ventilation in patients with COPD, Brochard and colleagues (19) and Kramer and coworkers (20) reported intubation rates of 74 and 67%, respectively. These figures are much higher than the intubation rate of 35% reported by Connors and colleagues (21) in a study of 1,016 patients admitted to hospital with an acute exacerbation of COPD complicated by hypercapnia. The proportion of patients with COPD in our study is markedly higher than in the APACHE III data base (22), where only 1% of 17,440 unselected admissions to 42 ICUs received mechanical ventilation because of an acute exacerbation of COPD. The fact that medical ICUs accounted for only 10% of ICUs in the APACHE III
TABLE 4 PERCENTAGE OF PATIENTS WITH TRACHEOSTOMY ACCORDING TO THE INDICATION FOR MECHANICAL VENTILATION AND THE DURATION OF VENTILATOR SUPPORT* Duration of Mechanical Ventilation Indication for MV COPD ARF Neuromuscular
1 to 7 d 5/82 (6.1) 14/555 (2.5) 4/25 (16.0)
For definition of abbreviations, see Table 2. * Numbers within parentheses represent percentages.
8 to 14 d 8/36 (22.2) 29/203 (14.3) 4/14 (28.6)
15 to 21 d 8/24 (33.3) 35/101 (34.6) 8/12 (66.7)
⬎ 21 d 36/49 (73.5) 122/188 (64.9) 22/32 (68.7)