Prolong Intubation Post Coronary Artery Bypass Grafts - Article Example

Prolong Intubation Post Coronary Artery Bypass Grafts Critical care units have a good number of patients who are intubated for prolonged duration of time. The most common causes for intubation are relief of upper airway obstruction, ventilatory assistance and to aid tracheo-bronchial toileting. The advent of high volume low- pressure tubes has made it possible for patients to be ventilated for as much as 3 weeks through the endotracheal tube (Cohen et al, 2000). According to the American Heart Association, Coronary artery bypass graft surgery or CABG is the most commonly performed surgery of the heart in the United States. The most common complication of this surgery is prolonged mechanical ventilation. Prolonged intubation can contribute to significant mortality and morbidity. It is associated with longer stay in the intensive care unit and also in the hospital, increased rate of infections, increased medical expenditure and other complications (Cohen et al, 2000). Other complications include atelectasis, decreased lung volumes and nosocomial pneumonia (Imanipour et al, 2008). Delay in activity regimens can also occur. Prolonged intubation can result in various laryngeal sequelae. Studies have shown that 63 to 94% of intubations result in laryngeal injuries of which 10- 22% are permanent sequelae (Cohen et al, 2000). The sequelae are directly related to the duration of intubation. The laryngeal sequelae include cough, dysphagia, hoarseness of voice, stridor, and aspiration. The injuries can manifest in the form of erythema, granulomas, ulceration, subglottic stenosis, arytenoid dislocations and vocal fold immobility (Cohen et al, 2000). Lanrygeal complications are also related to larger size of tube, higher cuff pressures, emergency intubations and skill of the intubating physician (Cohen et al, 2000). CABG is a costly procedure with a mean cost of about 44000 US$ (Branca, 2001 qtd. in Imanipour et al, 2008). 25% of the cost is due to the stay in critical care unit in the post operative period. The estimated mean duration of stay in the critical care unit ranges from 2.5days to 6 days (Doering, 1998; qtd. in Imanipour et al, 2008). The length of stay is obviously directly dependent on the duration of mechanical ventilation. Previously, cardiac patients were sedated and mechanically ventilated for more than a day after surgery to give time for major organs to recover from drastic physiological changes which are expected to be induced by cardiopulmonary bypass (Rady and Ryan, 1999; qtd. in Imanipour et al, 2008). The intensivists also thought that keeping the patient on mechanical ventilation reduced the work of breathing, improved gas exchange and decreased episodes of respiratory insufficiency (Axisa, 2002; qtd. in Imanipour et al, 2008). Mechanical ventilation also helped to get better control of hypertension, pain and anxiety. However, recent specialists debate the necessity for prolonged intubation to achieve homeostasis and hemodynamic stability (Imanipour et al, 2008). The term early extubation is not clear. While some intensivists suggest extubation at 6 hours postoperative, others limit it to 2 hours. Some others argue that 2 to 8 hours is a reasonable time to extubate (Imanipour et al, 2008). Early extubation allows early ambulation, thus reducing complications of prolonged immobility like pulmonary embolism, deep vein thrombophlebitis and pneumonia. It also improves patient comfort and reduces the cost of hospitalization (Imanipor et al, 2008). Predictors of prolonged post operative intubation in CABG patients are unstable angina, elevated creatinine, reduced FEV1and positive fluid balance 24 hours postoperative (Cohen et al, 2000). Several preoperative variables affect the timing of extubation in the post-operative period. These include gender, age, respiratory function, cardiac status and left-ventricular function (Imanipur et al, 2008). How much each of these variables significantly contributes to prolonged extubation is a much debated topic. Walthall et al (2001) reported that of all the above mentioned preoperative variables, only cardiac status had significant effect on the duration of intubation. Many intraoperative variables have also been studied to look into their effects on the duration of intubation. Some of these variables include duration of surgery, number of vessels that need to be revascularized and duration of cardio-pulmonary bypass (qtd. in Imanipor et al, 2008). Another important intraoperative variable studied is the type of conduit used. Internal mammary artery conduit increases the duration of intubation (Knapik et al, 1996). However many researchers are of the opinion that intraoperative variables have no role in affecting the duration of intubation (Walthall and Ray, 2002). It is important for nurses and other professionals to understand the benefits and risks of prolonged intubation and factors leading to delayed extubation, so that they can plan and act appropriately. Critical care nurses play a pivotal role in the care of CABG patients postoperatively. Infact, they are responsible for all aspects of care of the patient. At this juncture it is interesting to note that since critical care nurses take care of the patient all the time, more and more responsibilities are shouldered on them and the role of physician in post-operative intensive care is gradually diminishing. Critical care nurses are now well trained and are in a position to take up decisions about weaning of mechanical ventilation and also extubation. Some studies have reported that nurses extubate much more quickly than physicians because they are available all the time and thus the patients are benefited in nurse-led extubations (Esteban & Alia, 1998; qtd. in Imanipor et al, 2008). Understanding the role of preoperative and intraoperative variables helps in decision making and safe extubation. Certain scoring systems have been developed which predict the risk of delayed extubation in patients who have undergone CABG. Of these, the most popularly used ones are the Spivack Scoring System (SSS) and the Cardiac Risk Score (CRS). Yende and Wunderink (2002) studied the validity of these scoring systems in predicting prolonged mechanical ventilation in CABG patients. The exact definition of prolonged extubation is not clear. However, prolonged mechanical ventilation beyond 24 hours is noted in about 5.65 cases in those who have undergone CABG first time. In those who have undergone reoperation, the incidence of delayed extubation is 10.7% (STS National database, qtd. in Yende and Wunderink, 2002). Thus is becomes obvious to stratify the risk of prolonged intubation as a part of preoperative evaluation. SSS is based purely on preoperative risk factors and CRS is based on both preoperative and intraoperative risk factors. In the SSS scoring system, four comorbid risk factors will be evaluated: diabetes, smoking, unstable angina and congestive heart failure prior to hospitalization. Each of these factors will be assigned 0.25 points and the score will be added up. The added up score will be called total comormid risk factor score or COMFAC. From this SSS will be calculated using the formula SSS= 5.409 (COMFAC)- 0.437(ejection fraction)- 1.821. Those with a score >0 are considered high risk for prolonged intubation (Yende and Wunderink, 2002). In the CRS scoring, age (>75 years 3 points, 61- 75 years 2 points) and female gender (2 points) are the preoperative variables and excessive bleeding (6 points), ionotrope use (2 points), intra-aortic baloon pump (6 points) and atrial arrhythmia (2 points) are the intra- and post-operative variables. Patients with a score of more than 8 are likely to be mechanically ventilated for a longer time (Yende and Wunderink, 2002). The understanding of patient outcomes of prolonged intubation in CABG patients helps clinical nurse specialist (CNS) impart evidence-based practice. Evidence -based practice has become a necessary and important paradigm for nursing and medical care and management. Various studies have shown that implementation of evidence based guidelines by CNS promotes improved patient outcomes (McCabe, 2005). CNS influence all the three spheres of practice namely, nursing and nursing practice, patients/clients and organizations/systems. Factors which influence the achievement of evidence based practice (EBP) by CNS include known gained through experience and interaction with other nursing colleagues and medical professionals and also interactions with patients. Also, information from the organizations in the form of audit reports and policies and research reports contributed to the enhancement of evidence- based practice (Gerrish & Clayton, 2004). Barriers to the growth of EBP include, lack of time, lack of appropriate resources, deficiency in the perceived authority and decreased self-confidence about the ability to change practice (Gerrish & Clayton, 2004). Lack of staff and not having the right equipment and supplies also affect the facilitation of EBP (Gale and Schaffer, 2009). Thus it becomes obvious for health care organizations to incorporate multiple strategies to promote, enhance, facilitate and create a culture of EBP. There are many models propagating EBP. ACE star model is the most popular model to perpetuate EBP by CNS. According to the ACE Star Model, knowledge transformation in an EBP environment occurs in five stages namely: discovery, summary, translation, integration and finally evaluation. Based on these five important steps, the practice of a CNS falls into 5 domains namely, expert practitioner, researcher, consultant, educator and finally leader (Kring, 2008). This model involves both old and new concepts of improving care to provide a wholesome framework enabling organization of EBP processes and approaches (Academic Center for Evidence- Based Practice, 2004). This model is a simple depiction of relationships between the five stages of knowledge transformation as discussed above. This model helps a CNS to examine and apply EBP. Figure: 1: ACE Star Model of EBP (Academic Center for Evidence- Based Practice, 2004). My proposal for EBP is to use a preoperative screening tool to identify patients who can be extubated early. The need for this tool has come from the discovery of the fact that prolonged intubation in CABG patients has many complications. The morbidity and mortality increase in these patients when mechanically ventilated for long periods of time. The preoperative tool decreases the number of patients who need to be kept on ventilator for longer periods of time. Using of the tool is simple and the benfits are expected to be great! Adequate training and education of the nursing staff helps in the translation of information. Making preoperative screening tool mandatory integrates this proposal into the cardiac ICU system. Over a period of time, this tool can be evaluated and incorporated as hospital policy. Bringing about change Change in nursing practice can be brought about by using any of the change models. To apply EBP regarding extubation norms in CABG patients, I have chosen Lewin’s change theory. This model is one of the best models for change. It is known as ‘Lewin’s Action Research Model for Change.’ This model utilizes a self reflective type of summation, which often surrounds social situations. Action research focuses on the participants own thoughts that are formed, again in a reflective manner. This supposedly helps to draw upon a better comprehension of their own practices, so that improved care can be given to others. This theory involves an action of planning and fact gathering before proceeding on to the next phase of action. It ensures that all participants have a good comprehension of what is expected of them and keeps a strong focal point in the area of communication, which again is a necessity in nursing. There are 3 stages of change according to this model: Unfreezing: Prolonged intubation in all CABG patients must be changed. This change has to come because prolonged intubation has many side effects. It increases the mortality and morbidity of CABG patients. It also increases the duration of ICU and hospital stay, thus increasing the cost of health care. This change has to come from the chief intensivist incharge of cardiac ICUs. After reviewing suitable literature, it comes to my understanding that it is baseless to keep a CABG patient on mechanical ventilation for a longer duration. First of all, the traditional purpose for prolonged ventilation (for improving hemodynamic balance) has been disproved. Secondly, as I have presented earlier, prolonged ventilation has many side effects. Ofcourse, there may be some patients who 'really' need to be ventilated for longer duration. My suggestion here is that we have to identify patients who can be extubated early based on pre-operative screening tool and act accordingly. Hence I strongly recommend using of a tool which identifies patients who can be extubated early. Moving: I want to clearly stress on the fact that prolonged intubation in CABG patients has many complications and is totally unncessary. Preoperative screening tool helps identification of patients who can be extubated early. By using this tool, many patients can be extubated early safely. The cost to health care will decrease. The mortality and morbidity rates will decrease. Workload on the staff will also decrease. Refreezing: The literature review I have presented supports the change I have recommended. barriers to sustaining change are lack of knowledge, fear of change and inertia. The ways to sustain change are enduring support from the leader, having a reward system, establishing feedbacks and adapt the organizational structure. All those involved in the change should be suitable informed, trained and supported . Conclusion Traditionally, patients after CABG were kept intubated for 24 hours to give time for hemodynamic stability. However, there is evidence that prolonged intubation has many side effects and infact, it is more beneficial to exclude the patient as early as possible. Hence ‘early extubation of suitable CABG patients’ needs to be incorporated in EBP. This can be done by ACE Star model transformation. The change can be brought about by applying Lewin’s model for change. References Academic Center for Evidence- Based Practice (2004). ACE Star Model Of Knowledge Transformation. The University of Texas Health Science Center at San Antonio. Retrieved on 22nd Feb, 2009 from http://www.acestar.uthscsa.edu/Learn_model.htm Cohen, A.J., Katz, M.G. and Frenkel, G. et al (2000). Morbid results of prolonged intubation after coronary artery bypass surgery. Chest, 118(6), 1724- 1731 Gerrish, K., & Clayton, J. (2004). Promoting evidence-based practice: an organizational approach. J Nurs Manag.,12(2), 114-23. Gale, B.V., and Schaffer, M.A. (2009).Organizational readiness for evidence-based practice. J Nurs Adm., 39(2), 91-7. Imanipour, M., Bassampoor, S.S., and Nasrabadi, A.N. (2008). Intraoperative variables associated with extubation time in patients undergoing coronary artery bypass graft surgery. Japan Journal of Nursing Science, 5(1), 23- 30. Knapik, P., Spyt, T. J., Richardson, J. B. & McLellan, I. (1996). Bilateral and unilateral use of internal thoracic artery for myocardial revascularization, comparison of extubation outcome and duration of hospital stay. Chest, 109, 1231–1233. Kring, D.L. (2008). Clinical nurse specialist practice domains and evidence-based practice competencies: a matrix of influence. Clinical Nurse Spec., 22 (4), 179- 183. McCabe, P.J. (2005). Spheres of clinical nurse specialist practice influence evidence-based care for patients with atrial fibrillation. Clinical Nurse Spec., 19(6), 308-317. Rangachari, V., Sundararajan, I., Sumathi, V., and Kumar, K.K. (2006). Laryngeal sequelae following prolonged intubation: A prospective study. Indian J Crit Care Med, 10, 171- 175. Walthall, H., Robson, D. & Ray, S. (2001). Do any preoperative variables have an effect on the timing of tracheal extubation after coronary artery bypass graft surgery? Heart and Lung, 30, 216–224. Walthall, H. & Ray, S. (2002). Do intraoperative variables have an effect on the timing of tracheal extubation after coronary artery bypass graft surgery? Heart and Lung, 31, 432–439. Yende, S. and Wunderink, R. (2002). Validity of Scoring Systems to Predict Risk of Prolonged Mechanical Ventilation After Coronary Artery Bypass Graft Surgery. Chest, 122 (239-244). Read More