Discussion
Mechanical ventilation is a life supportive therapy for critically ill patients with respiratory failure. Studies report that approximately 40% of adult patients admitted in an intensive care setting require invasive mechanical ventilation. Two large seminal clinical trials (Brochard 1994;Esteban 1995) indicated that the clinical processes promoting timely recognition of a patient’s readiness to wean were more important in reducing the duration of mechanical ventilation than the weaning method itself.(2)Over the years, the weaning process has evolved from being based on education and experience of the treating clinician to a proper structured protocol-directed approach. This protocol-based weaning is slowly gaining impetus in critical care units around the globe because of its success in reducing the prolonged duration of mechanical ventilation and hence, indirectly reducing the costs related to health care. A number of factors influence the effectiveness of this weaning protocol such as ICU organization, available resources, hospital culture and healthcare professional characteristics. Therefore, the designing of the weaning protocols should take into consideration the social and cultural environment in which they are to be implemented to accommodate the challenges in clinical practices in the concerned ICU environment for a successful implementation. A study conducted by Rose et al (11) revealed that the prevalence of implementation of weaning protocol in European adult ICUs was 56% to 69%. However no such study highlighting the impact of implementation of weaning protocols has been reported from a resource limiting setting like ours. Hence we conducted this study for assessment of current weaning practices and determine the impact of implementation of protocol based weaning in a high burden setting.
The weaning protocol was broadly divided into four major steps namely, assessment of readiness to wean, pre-SBT trial, post-SBT trial and extubation screen, which were included as quality indicators in our study. There was a significant improvement with respect to compliance to these steps of the weaning process as per protocol in the post intervention phase. Most of the previous studies mentioned have not assessed the compliance in following these steps of weaning protocol and have assumed the compliance in following various steps of weaning to be 100%. However our study has tried to take a more realistic picture of the scenario that would happen in an ICU in a high burden, resource-limited setting wherein the compliance is affected by the availability of resources.In our study, among the readiness criteria only two, assessment of GCS and hemodynamic instability were being followed in a large proportion of patients at baseline. However, in the post intervention phase the compliance to these parameters remained high while to other components increased. A similar improvement was seen in the compliance to components of pre SBT and post SBT monitoring phase in the post intervention phase as compared to pre intervention phase. Among the secondary outcomes, although there was a trend towards reduction of duration of mechanical ventilation in the second phase, the results did not achieve statistical significance. There was an increase in the proportion of patients who were successfully extubated, although the results did not reach statistical significance. The frequency of complications like re-intubation and VAP rates were lower in the post intervention arm although the difference was not statistically significant. This result was consistent with study conducted by Krishanet al in which no difference was found in number of patients requiring reinstitution of mechanical ventilation, ICU length of stay and hospital mortality in control and protocol weaning group.[9] Elly et al conducted a study on neurosurgical patients showed that implementation of weaning protocol based on traditional respiratory physiologic parameters had practical limitations in postoperative patients with no significant differences in complications, mortality and duration of mechanical ventilation in control and intervention group.[8] Simeone et al conducted a study on patients undergoing cardiac surgery and reported lesser duration of mechanical ventilation and length of ICU stay in the protocol weaning group as compared to usual group.[12](Table 2)
This study is first of its kind, conducted in a high-burden, resource-limited setting for evaluation of effect of implementation of protocol-based weaning methods in a pragmatic scenario. The study revealed low compliance to various parameters assessed as a part of weaning process. Training of resident doctors was successful in improving compliance with protocol-based weaning process.
There are a number of limitations in the study. This was short duration study with small number of patients precluding any meaningful conclusions on the effect on patient outcomes. A larger study population could have shown a more significant change in the quality indicators of patient outcomes, which were assessed. Even with a well-organized study, there was less than 90% compliance with some parameters in the weaning protocol. This means that there are many variables involved in the process improvement. In this study, these barriers to protocol compliance improvement, including the contributions of physician and allied staff behaviour, were not measured. Identifying and rectifying these variables could have led to a better rate of compliance with weaning protocol in this study.