This was a prospective thought of 52 patients that were extubated in our medical intensive care unit.

This was a prospective thought of 52 patients that were extubated in our medical intensive care unit. Rapid shallow breathing, delineateed by a ratio of oftenness to tidal volume (f/VT) of more than 105 was evaluated either forward continuous positive airway pressure or influence support prior to extubation as a marker of extubation result Twelve out of 13 patients (92 percent) with rapid shallow breathing (f/VT ratio [greater than] 105) were favorably extubated. Out of 9 extubation failures simply 1 patient had a f/VT ratio more than 105 (11 percent) A measured f/VT ratio of les than 105 had a sensitivity and specificity of 72 and 11 percent respectively, for extubation succes Patients who had unfortunate outcomes were ventilated for a significantly more postponeed period (9.6 [+ or -] 68 d v 46 [+ or -] 39 d unpaired t proof p = 0.004). We close that the presence of rapid shallow breathing during a weaning trial with the patient forward partial ventilatory support does not necessarily bar successful extubation.

Weaning is the withdrawal of mechanical ventilatory support, or alternatively "liberation" has been glance ated to be a more appropriate term[1] This is usually attempted after the resolution of the precipitating end that originally resulted in respiratory failure and the institution of mechanical ventilatory support. It is generally agreed that to start in succession a weaning trial the patient has to have the ability to breathe spontaneously, be clinically stable and improving, and preferably be awake and alert. Sahn and Lakshminarayan[2] have shown that in patients ventilated for les than a week, a minute compass of 10 L or les and a maximal voluntary tome two times the resting minute body or greater, or when maximal inspiratory influence is 30 cm [H.sub.2]O or les had a sensitivity of 92 percent a specificity of 100 percent and a positive predictive value of 100 percent for weaning success

For patients with extended ventilation, and especially those with chronic lung disorders, more sophisticated indicex have been propos to predict weaning succes These indicex include respiratory rate,[3] vital capacity,[4] airway occlusion pressure[56] the augmentation of airway occlusion squeezing during hypercapnic challenge,[7] diaphragmatic function and air of paradoxical breathing,[8] work of breathing,[9] and the air of rapid shallow breathing.[10,11] However, a certain number of of these indicex may not be applicable in somewhat old patients ([greater than or equal to] 70 years).[12] Furthermore, there have been debates regarding ways of conducting weaning trials that may optimize weaning success[13] especially utilizing different qualitys of ventilatory support during the weaning process[14-21]

Weaning failure may proceed from various problems including hypoventilation secondary to decrease central drive for respiration, respiratory muscle weakness or fatigue, impaired pulmonary gas exchange, increased ventilatory demand, and increased work of breathing from decreased compliance or increased resistance. Other factors that may have to be considered include the patient's nutritional status, acid-base balance, electrolyte horizontal thyroid function status, mental status, and the ability to handle the secretions of the airway.[13,22]

In an earlier contemplation of 17 patients, Tobin et al;x1;x0 demonstrated that probably as a be the effect of abnormal pulmonary mechanics, rapid shallow breathing issueed in inefficient gas exchange and preced weaning failures. Yang and Tobin;x1;x1 then evaluated prospectively rapid shallow breathing give an account ofed by the ratio of respiratory oftenness to tidal volume (f/VT) and reported that a f/VT ratio greater than 105 was the mostly accurate predictor of weaning failure. We report the issue from extubating 52 patients in our medical ICU, and correlate the terminate with the measured f/VT ratio.

PATIENTS AND METHODS

Clinical Data

Fifty-two patients who were extubated in the medical ICU in the National University Hospital, Singapore, were registered into the study. Patients were ventilated using either the Siemens-Elema Servo 900C or the Ohmeda CPU ventilator. couple modes of partial ventilatory support during the weaning period were employed: crushing support (PS), 30 patients, and continuous positive airway compressing (CPAP), 32 patients. Patients were in succession their respective weaning modes for 1 h before the following measurements were recorded, and then an arterial vital fluid sample was obtained. Expiratory VT was determined by way of averaging ten consecutive dial readings forward the ventilator. Respiratory rate was thinked over 1 min. Vital capacity, maximal voluntary dimensions and maximum inspiratory pressure were not measured. Note that this course of measuring the f/VT ratio forward partial ventilatory support differs substantially from Yang and Tobin's study[11] where the f/VT ratio was measured with no ventilatory support (free spontaneous breathing). All the patients in the thought were extubated, and deemed to have favorably completed the weaning trial by means of the individual physician in charge. Criteria for a happy weaning trial were based forward the patient's clinical response to the weaning trial (viz, no diaphoresis, no tachycardia, no hypertensive answer and no acute tachypnea), and the arterial line gas level results at the extremity of the trial (less than 10 mm Hg rise in [PaCO.sub.2]). Note that the patients were extubated irrespective of the f/VT ratio. Extubation was considered vain if the patient required reinstitution of ventilatory support (mechanical ventilation or CPAP mask--Downs be derived generator No. 9250, Vital Signs Inc, Totowa, NJ) or died within 24 h of extubation. The decision to reintubate the patient was based upon clinical deterioration as evidenced by the agency of respiratory distress or increasing drowsiness from hypoxia or hypercapnia. The CPAP mask was useed as a prelude to reintubation if the patient had had a lucky weaning trial with the CPAP gradation based on the arterial offspring gas level results, and suspected left ventricular dysfunction or adult respiratory distress syndrome as a cause for their respiratory distress.

...