This study was designed to seek a possible relationship between the length of time (LOT) in which a patient has received prolonged ventilator support (VS) and the outcome of weaning.
Patients admitted to this hospital in 2001 and 2002 (n=367) were assessed for weanability. Patients deemed weanable (n=155; 42%) underwent weaning. The dates of initiation of VS were obtained from the referring hospitals. Measures: a) total time in days of VS for each patient prior to weaning being initiated; b) number of patients successfully weaned, i.e., at least 4 weeks free from VS; c) number of patients who failed weaning, i.e., weaning attempted but not successful. Because the data were not normally distributed nonparametric analysis was undertaken.
No significant differences were found in the LOT in which patients received VS who were successfully weaned (n=116; 75%) and those in whom weaning was attempted and failed (n=39; 25%). In the successful group, there was one outlier who received VS for 1,124 days before weaning was undertaken and succeeded. Statistical calculations using the Mann-Whitney U test were performed including and excluding the outlier. When the outlier was removed the distribution approximated normal and then a t test also showed no difference in the LOT of VS between the two groups. No significant differences between the two groups were found in the number of days for weaning to succeed or deemed to have failed. Moreover, there were no relationships between the LOT on a ventilator and the number of days required for the weaning process to succeed or deemed to have failed.CONCLUSIONS: The LOT in which a patient was on VS prior to weaning did not influence the likelihood of weaning being successful. There was no relationship between the LOT on VS and the LOT of the weaning process itself.
The LOT in which a patient is on prolonged ventilation should not be a consideration in decisions about weanability.
J.J. Vecchione, None.