Subglottic secretion drainage for preventing ventilator-associated pneumonia: A meta-analysis

Subglottic Drainage

Subglottic secretion drainage for preventing ventilator associated pneumonia: A meta-analysis

It has been established that the incidents of ventilation-associated pneumonia could be reduced by almost half by the use of endotracheal tubes. This would assist in reducing the morbidity and mortality rates of the patients. It is estimated that VAP affects around nine -27% of the intubated patients who are receiving mechanical ventilation. This is a large number considering that using subglottic secretion drainage has the capability to reduce the incident rates. Frost et al. (2013) conducted a meta-analysis that combined information from published studies on the effect of subglottic drainage of secretions on VAP incidents in adult ICU patients. The researchers established that using subglottic drainage of secretions reduced the risk of VAP by almost 48%. The researchers discovered there was no considerable reduction in the mortality rates in both the ICU and hospital from the published studies. The time a patient spends on a mechanical ventilation could be reduced. Time before a patient develops a VAP is increased when using specialized endotracheal tubes that are designed to drain subglottic secretions. VAP has been associated with substantial morbidity and mortality in the ICU. The possibility of preventing VAP is increased when using SSD. The draining of secretions should be carried out in scheduled intervals with a minimum of one hour and maximum of 4 hours. This would ensure that there is no overflow and risk of the discharge flowing back to the patient's body. The head elevation is also vital to ensure that the discharge flows outward. The elevation should be between 30-40 degrees.

Intermittent Subglottic Secretion Drainage and Ventilator-associated Pneumonia

The use of subglottic secretion drainage (SSD) has remained a controversial subject since the studies conducted have differing points-of-view (Lacherade et al., 2010b). The single center trials conducted by Valles and Artigas (1995) and Bouza et al. (2008) did not confirm that the use of SSD did in fact reduce the incidence of VAP. A meta-analysis conducted on these studies by Dezfulian et al. (2005) concluded in their study that there was an effective reduction in the early-onset rate of VAP when using SSD. In 2003 and 2004, SSD was not considered as a measure to prevent VAP in Canadian and United States guidelines. It was only suggested as a measure (Dodek et al., 2004). Currently, SSD is the recommended method for preventing VAP. A multicenter trial conducted by Lacherade et al. (2010b) at four French centers established that there was a considerable decrease in the rate of VAP when using SSD. The researchers also analyzed the incidence of early and late-onset of VAP. This randomized study involved patients above 18 years admitted to the ICU. The researchers screened for patients intubated with an endotracheal tube that allowed for subglottic secretion drainage. The patients were also expected to require at least 48 hours of mechanical ventilation in order to participate in the study.

The researchers had two randomly assign patients in order to have a controlled group and SSD group. Each group consisted of 220 patients, which allowed for detection of any differences. The study period lasted for 3 years, and at the end of it only 333 patients were included. The subglottic secretions were manually suctioned once every hour. There were daily screening for any occurrence of VAP for all the randomized patients. The screening was maintained until the first episode of VAP occurred. Diagnosis of pneumonia within the first 48 hours of the ventilation onset was not considered as caused as ventilator-associated. Early-onset was determined to occur within five days of the mechanical ventilation initiation and late-onset occurred after the five days. The researchers did not assess late-onset for patients who did not undergo mechanical ventilation, but they assessed the early-onset for all the patients. The study confirmed that SSD reduces VAP incidents. VAP occurred in 14.8% of the SSD group and 25.6% in the control group. For the patients in the SSD group, early and late-onset of VAP was reduced significantly. In the SSD group early onset was 1.2% and late onset was 18.3%. For the control group, early onset was 6.1% and late onset was 33%. There was no substantial difference in the duration of stay in the ICU for both groups (Bouza et al., 2003). The study indicated that there is a possibility of reducing the risk of VAP by using SSD by 11%.

Critical analysis of care given to patient

The patient was intubated with an endotracheal tube that had suction above the cuff. The tube had the capability to secrete subglottic discharge, which ensured that there was no accumulation of secretions within the body. The patient was given good care, especially considering that they developed a condition that is associated with the intubated tube. Various studies have indicated that the best way to discharge the subglottic secretions is using SSD, but the studies also indicate that there is a likelihood of the patient developing VAP. SSD only delays the onset of VAP, but does not have the capability to prevent. There are other ways proposed to reduce the onset of VAP in intubated patients. Oral health of the patient would ensure that no oral secretions accumulate on the tracheal cuff, which would leak into the lungs. Oral health has also been identified as effective in reducing the risk of VAP (Kollef, 1999).

Draining the pleural effusions provides the patient with much needed relief. The 61-year-old patient did not have the strength to endure the pain caused by the effusions, and they did receive relief once they were intubated. A 2012 study by Fysh et al. (2012) found that the patient who chose to use a discharge tube spent less days in hospital, had less recurrence of effusion, and quick improvement in the quality of their life as compared to patients who opt for other methods. Another study determined that the drainage of pleural effusion in patients on mechanical ventilation was safe, and it appeared to improve oxygenation Goligher et al. (2011). There was no information supporting or refuting the benefits of clinical outcomes like duration of stay or duration of ventilation. There is a reduction in relative risk and improvement of the patient's mortality and morbidity when using SSD.

A study conducted by Ledgerwood et al. (2013) on the effects of tracheotomy tubes that have suction above the cuff established that the tubes have the capability to reduce VAP incidents. The amount of time spent in ICU and on the ventilator was also reduced. This does demonstrate that the patient was accorded the best treatment available to drain pleural effusion. The development of haemothorax/pneumothorax is anticipated in most patients who are intubated, but the risk is normally reduced. According to the different studies conducted, the likelihood of a patient suffering from VAP is decreased slightly when using SSD. The patient would still have contracted VAP if they were not intubated with the endotracheal tube. Therefore, the patient ended up incurring higher medical costs as they had to pay for the tube, and haemothorax/pneumothorax treatment. If they had not been intubated the patient would have only paid for the sickness. This additional cost is easily overlooked before the patient suffers from VAP, but once they are affected, the consequences are the same for all patients.

The tracheotomy tube should be suctioned after every one hour. During this procedure, the healthcare provider uses a syringe to suck the discharge from the tube. Healthcare providers have to decontaminate their hands before and after the procedure (Lacherade et al., 2010a). Failure to decontaminate their hands could result in passing of infections to the patient. This risk is increased since the patient has no way of knowing the hygiene of the care provider. The patient relies on the care provider to sanitize their hands before carrying out the suctioning procedure. Germs can easily be transmitted from the care provider to the patient if they do not sanitize their hands. This is because the tube is directly inserted in the patient's throat. The use of gloves when suctioning the discharge is highly recommended, this would ensure that both patient and nurse are protected at all times during the procedure.

The study by Smulders et al. (2002) was not able to identify any difference between control patients and those fitted with tracheotomy tubes. This lack of difference indicates that there is need for further research and development to determine the true efficacy of the tube. This would ensure that the little difference identified by the various studies is eliminated or justified. In regards to the patient, it is still not certain why they still suffered VAP. If the tube was effective in reducing the chances of the disease, then the patient was unlucky. The studies have all spoken about the benefits gained by using the tube, but none wants to accept that conducting a controlled study does not indicate the reality. The tyranny of numbers is that a small percentage cannot be used to indicate the truth for the population. There is still a possibility that the studies were biased since they allowed the nurses and the physicians to know of the study and the different patients. There is a possibility that the nurses took extra care over the intubated patients in the study than those within the hospital.

Pleural effusions could be removed using medications, but this is dependent on the type effusion. For the patient, the effusion required the intubation of an endotracheal tube size 8. This was the recommended size for an adult male as determined by the physician. According to Muscedere et al. (2011), the patient was not given the tube to prevent VAP, but rather in order to allow for the discharge of the pleural effusions. The failure to discharge properly the effusions would have resulted in a severe development of the disease. The discharge would have been deposited in their lower respiratory tract. Thus, the tracheotomy tube delayed the patient's development of VAP, which allowed them to recover progressively. The lack of the tube would have led to an early-onset of VAP.

Conclusion

The prevention of VAP is possible using SSD. The different studies and meta-analyses provided in the paper have determined that VAP can be prevented using SSD, but that is not a guarantee since some of the common cause of VAP are able to colonize the trachea. They adhere themselves to the endotracheal tube and this results in their passage to the respiratory tract. Prevention of VAP is better than curing the disease, and preventing the occurrence of VAP is beneficial to the patient, as they will not incur additional costs in treating pneumonia. The increased costs associated with purchase of the tube are mitigated over the long-term although there is no formal economic analysis done. All the research studies have concurred that the amount of time a patient spends in ICU is reduced, and they spend 3 days less on the mechanical ventilator. The reduction in number of days directly affects their economic savings as the ICU is expensive than a general ward. Speed of recovery is improved as they spend less time breathing using a machine and more time breathing on themselves. This does strengthen their lungs and increase their speed of recovery. Even with SSD, there is still a possibility of a patient contracting VAP. The percentage of this probability is reduced drastically when using SSD as seen in the different studies.

In the future, SSD needs further research to determine its full efficacy and methods of improvement. Currently, there are newer tubes purported to function better and eliminate the need for the nurse to suction. The tubes are able to discharge the suction, and this eliminates the need to keep checking on the tube. More research should be conducted to uncover more information on how to fully eliminate VAP in ICU patients.