• Tuberculosis and Respiratory Diseases
• /
• v.44 no.6
• /
• pp.1326-1331
• /
• 1997

Background : Weaning is the process of switching a patient from mechanical ventilator to spontaneous breathing. A number of different weaning techniques can be employed. At recent study, conventional spontaneous breathing trial was superior to other techniques, such as intermittent mandatory ventilation(IMV) or pressure support ventilation(PSV). But adequate observation time of the spontaneous breathing trial was not determined. We reported the effectiveness of weaning and extubation following a 60 minutes spontaneous breathing trial with simple oxygen supply through the endotrachial tube. In this study, we tried to shorten the spontaneous breathing time from 60 minutes to 30 minutes. If weaning success was predicted after 30 minutes spontaneous breathing, extubation was done without reconnection with ventilator. Methodes : Subjects consisted of 42 mechanically ventilated patients from August 1994 to July 1995. The weaning trial was done when the patients recovered sufficiently from respiratory failure that originally required ventilatory assistance, the patients became alert and showed stable vital sign, and arterial $O_2$ tension was adequated($PaO_2$ > 55 mmHg) with less than 40% of inspired oxygen fraction. We conducted a careful physical examination when the patients was breathing spontaneously through the endobronchial tube for 30 minutes. We terminated the trial if a patients was any of following signs of distress; cyanosis, diaphoresis, tachypnea(above 30 breaths per minute), and extreme tachycardia. Patients who had none of this features during spontaneous breathing for 30 minutes were extubated promptly. Result : 17 weaning trials of 15 patients were done in 42 mechanically ventilated patients. Successful weaning and extubation was possible in 14 trials of total 17 trials. In this 14 patients, 8 patients were extubated after 30 minutes spontaneous breathing, 3 patients were extubated after 60 minutes spontaneous breathing, and 3 patients needed over 3 hours for extubation from weaning. We found similar overall success rate compared with weaning following a 60 minutes spontaneous breathing trial. Conclusion : From the result of present study, we believe that weaning and extubation from mechanical ventilation following a 30 minutes spontaneous breathing with $O_2$ supply through the endotracheal tube is a simple and effective method.

• Tuberculosis and Respiratory Diseases
• /
• v.42 no.3
• /
• pp.361-369
• /
• 1995

Background: A number of different weaning techniques can be employed such as spontaneous breathing trial, Intermittent mandatory ventilation(IMV) or Pressure support ventilation(PSV). However, the conclusive data indicating the superiority of one technique over another have not been published. Usually, a conventional spontaneous breathing trial is undertaken by supplying humidified $O_2$ through T-shaped adaptor connected to endotracheal tube or tracheostomy tube. In Korea, T-tube trial is not popular because the high-flow oxygen system is not always available. Also, the timing of extubation is not conclusive and depends on clinical experiences. It is known that to withdraw the endotracheal tube after weaning is far better than to go through any period. The tube produces varying degrees of resistance depending on its internal diameter and the flow rates encountered. The purpose of present study is to evaluate the effectiveness of weaning and extubation following a 60 minutes spontaneous breathing trial with simple oxygen supply through the endotracheal tube. Methods: We analyzed the result of weaning and extubation following a 60 minutes spontaneous breathing trial with simple oxygen supply through the endotracheal tube in 18 subjects from June, 1993 to June, 1994. They consisted of 9 males and 9 females. The duration of mechanical ventilation was from 38 hours to 341 hours(mean: $105.9{\pm}83.4$ hours). In all cases, the cause of ventilator dependency should be identified and precipitating factors should be corrected. The weaning trial was done when the patient became alert and arterial $O_2$ tension was adequate($PaO_2$ > 55mmHg) with an inspired oxygen fraction of 40%. We conducted a careful physical examination when the patient was breathing spontaneously through the endotracheal tube. Failure of weaning trial was signaled by cyanosis, sweating, paradoxical respiration, intercostal recession. Weaning failure was defined as the need for mechanical ventilation within 48 hours. Results: In 19 weaning trials of 18 patients, successful weaning and extubation was possible in 16/19(84.2 %). During the trial of spontaneous breathing for 60 minutes through the endotracheal tube, the patients who could wean developed slight increase in respiratory rates but significant changes of arterial blood gas values were not noted. But, the patients who failed weaning trial showed the marked increase in respiratory rates without significant changes of arterial blood gas values. Conclusion: The result of present study indicates that weaning from mechanical ventilation following a 60 minutes spontaneous breathing with $O_2$ supply through the endotracheal tube is a simple and effective method. Extubation can be done at the same time of successful weaning except for endobronchial toilet or airway protection.