The Effects of Uncuffed Endotracheal Tubes Versus Cuffed Endotracheal Tubes - Research Proposal Example

Research Proposal: The effects of uncuffed endotracheal tubes versus cuffed endotracheal tubes in pediatric patients under eight years old Introduction Preformed or premoulded oral tracheal tubes were initially described and introduced by Ring, Adair and Elwyn (Rae) tubes during the late 1970s. These implements were molded in an angle appropriate for placement at the patient's oral cavity for the reduction of the occurrence and effects of kinking. This gave them immense application in surgery of the regions of the mouth and the face. Preformed endotracheal tubes (ETT) are made of PVC and come in oral and nasal versions although these fit more into an oral gag, secured through the lower lip to prevent unintended extubation (Weiss et al. 734; Cox 669; Ho 169; Fine & Borland 38). Problems arose in endotracheal intubation particularly for patients that require long-term ventilatory support. Subglottic stenosis was a rare occurrence before the 1960s when tracheostomy was the generally accepted procedure for long-term ventilatory support. However, when prolonged endotracheal tubes were widely used especially for critical care as well as for neonatal intensive care patients, subglottic stenosis cases increased associated with chronic morbidity and fatality (Weiss et al. 734; Cox 669). Traditionally, uncuffed endotracheal tubes were accepted as the tube of choice for intubtation in children below the age of 8 years in all types or duration recommended. This practice, although widely promoted, is being questioned with the advent of new researches on the equal or better performance of cuffed endotracheal tubes in the specified age group. More studies are warranted to once and for all clear this outdated knowledge to further the science in pediatric anesthesia (Ho et al 169; Fine & Borland 38; Weiss et al. 80). Another important area for study, apart from the design and material of cuffed pediatric endotracheal tubes, are the proper tube size and position and depth markings for the said age group. Not only can the success of usage of cuffed tubes be assessed by answering issues around these properties but also the appropriateness of having health care practitioners other than the physician perform endotracheal intubation (Cox 669; Ho 169; Fine & Borland 38). The objectives of this study are (1) to evaluate the difference between a cuffed and an uncuffed endotracheal tube; (2) to determine the success rate of placement; (3) to evaluate the adverse effects of ETT application to patients below eight years old in the non-emergent, elective surgical, operating room setting; and (4) to assess proper tube size selection and placement by an experienced practitioner (nurse anesthetist with greater than one year experience) and relatively inexperienced practitioner (student nurse anesthetist). The above-mentioned objectives will be used to test the following hypotheses: (1) A cuffed endotracheal tube can have equal or better success rates through proper placement by either nurse practitioner; (2) The supposed adverse effects of cuffed ETT such as subglottic edema can be minimized by proper tube size and placement; (3) The experienced practitioner is capable of proper placement of both types of ETT; and (4) the inexperienced practitioner can have higher success rates and reduced laryngoscopy repetition with the cuffed endotracheal tube. Background Applications of endotracheal tubes include the protection of the airway, maintenance of airway integrity, ventilation through positive pressure, induction of positive and expiration pressure, pulmonary outlet and promotion of sufficient oxygenation. Most surgical procedures require short-term or temporary endotracheal tube usage while critical care interventions generally utilize long-term endotracheal tubes (Weiss et al. 734; Cox 669). Endotracheal intubation for anesthesia in adults was developed as early as the 1920s but appropriate apparatus and technique for children were not yet designed during those years. Even until the 1940s, endotracheal intubation was still rarely performed in children as available tubes were deemed inappropriate and damaging to their airway. An alternative for children requiring long-term respiratory support at that time was tracheostomy, a technique hounded with a set of side-effects on its own. Long-term nasotracheal intubation with uncuffed tubes were widely accepted in the 1960s for pediatric intensive care units and later assessed as safe from the risk of getting subglottic stenosis (Ho 169; Fine & Borland 38; Weiss "Shortcomings"78) . Until recently, cuffed endotracheal tubes were the recommended tubes for use with special conditions in children below eight years old. These were used noting the advantages of the presence of the cuff as opposed to its earlier form. The advantages of using cuffed endotracheal tubes included the following: reduction in gas leak around the tracheal tube, reduction in the need to change the tube, better ventilation with higher intubation pressures, reduced risk of aspiration, enhanced accuracy of tidal volume, lowered pollution, and reduction of risk for subglottic stenosis. However, subsequent clinical experience grew with concerns that the cuff could actually cause tracheal mucosal injury which can increase the risk for subglottic stenosis. The cuff can also lead to a reduction of the internal diameter left for the tracheal tube therefore necessitating the use of a tube with smaller internal diameter which invariably causes higher airway resistance. Higher airway resistance obviously leads to increased work of breathing and harder tracheo-bronchial suctioning (Weiss et al. 734; Cox 669). Several researches aimed to compare the applicability and success rates between cuffed and uncuffed endotracheal tubes in patients under the eight years of age. A study by Newth et al. (333) found no relationship between the success rate or risk of subglottic edema in children with cuffed or uncuffed endotracheal tubes. According to Cox (2005), although the study involved large quantities of samples, it was unfortunately limited due its non-randomized, un-controlled and un-blinded experimental design. Nonetheless, the study provided basic evidence that the cuff in cuffed endotracheal tubes does not pose suspected danger to the airway of children in the critical care setting. Another study by Khine et al. (627) demonstrated a higher incidence of reintubation in uncuffed endotracheal tubes than in cuffed ones. Moreover the group was also able to show that cuffed tubes were associated with a lesser probability of fresh gas flow needs compared to uncuffed tubes. Weiss et al. ("Comparison of Cuffed and Uncuffed" 734) et al., on the other hand, determined the differences in the length, position, placement and other relevant characteristics of both cuffed and uncuffed endotracheal tubes. They found out that bend to tracheal tube tip distance were similar between same-size cuffed and uncuffed tubes, upper border to tracheal tube tip distance was shortest in some cuffed compared to uncuffed tubes, and that the tested tubes needed improved design as determined by the improper placement of cuffed tubes. According to Ho et al., (169), one disadvantage of cuffed endotracheal tubes is the decreased margin of safety. According to their paper, the uncuffed tube's margin of safety is equal to the approximate length of the trachea whereas in cuffed tubes, this margin is reduced of approximately 50% or more. Proper insertion depth of endotracheal tubes in children is important to prevent inadvertent bronchial intubation, inflammation of the carina, and unintentional extubation. The length of the trachea in newly born and infants is relatively short, placing a very small margin for error. Therefore, intubation depth marks at the tube tip have been standardized for optimal positioning of the tube tip in the mid-tracheal region. However, studies found a large discrepancy in the position and the existence of depth marks among various types of uncuffed and cuffed tracheal tubes. Accordingly, the absence of intubation depth marks and improperly placed depth marks in cuffed endotracheal tubes were also previously noted. In these cases, the tube tip will become embedded dangerously deep in the trachea, when positioned following the depth marks (Ho 169; Fine & Borland 38; Weiss et al. "Appropriate Placement" 80). These studies highlight the importance of the design of the cuffed and uncuffed pediatric endotracheal tubes since this will play a major role of the position of the tubes in the trachea. It is well understood that the issue surrounding the appropriate size and depth markings needs urgent investigation and clarification. According to Weiss et al. ("Intubation Depth" 721) data that are needed to compare the properties of cuffed tracheal tubes for correlation with complementary anatomical data on neonates, infants and children in different ages are not sufficient. Another area that is deficient in available data is the capability studies of the different health practitioners in the placement and maintenance of the endotracheal tubes in children in the three age groups. Most studies focus on the physician or the anesthesiologist in the evaluation of the proper usage and success rates of endotracheal tubes in children. Rarely are studies wherein health professionals such as nurse practitioners and student nurses are considered for capability in the practice of endotracheal tube placement. More specifically is the assessment of the level of experience of such experienced practitioner (nurse anesthetist with greater than one year experience) and relatively inexperienced practitioner (student nurse anesthetist) in relation to the type of endotracheal tubes and the corresponding adverse effects and success rates. In short, research gaps related to the usage of endotracheal tubes in children include the following. First are the differences in design and position. Second are the success rates of each particular type of design in children at different years of age below eight including adverse effects and other disadvantages. Third are data on the capability of relatively experienced and inexperienced nurse practitioners in the selection of tube size and placement of endotracheal tubes for children below eight years of age. Therefore, there is a need to gather and analyze data on the differences of design of endotracheal tubes in relation to the nurse practitioner applying them and the corresponding success or adverse effects. Research Design The research design of this proposal is divided in four parts. The first part will be the determination of the design differences of cuffed and uncuffed endotracheal tubes. The second part will involve determination of the success rate of tube placement for each type. The third part will be on the identification of the adverse effects, if present, in endotracheal tube application in children below eight years old in the non-emergent, elective surgical, operating room setting. The last part will include the assessment of the capability of nurse practitioner in two levels of experience in the selection and placement of endotracheal tubes in children below eight years old. I. Differences between Cuffed and Uncuffed Endotracheal Tubes The determination of the differences between cuffed and uncuffed endotracheal tubes will be undertaken through the measurement of the different dimensions of the two types of tubes. For each type, three brands, one for every size or indication variant, for a total of 54 (27x2) will be utilized in this study. The names, specifications and other information of the tubes to be evaluated will be documented. Tubes will be classified and arranged according to the relevant characteristics such as size, indication and presence or absence of cuff. Using a sliding caliper with a precision of 1/10 mm, distances between the following parts will be measured: (a) tube tip and lower cuff border, (b) width of the cuff, (c) tube tip and upper cuff border, (d) tube tip and depth marking, (e), inner diameter of the cuff, (f) outer diameter of tube. Measurements of the parts will be performed by three persons to eliminate bias and increase accuracy. II. Success Rates of Cuffed and Uncuffed Endotracheal Tubes In the evaluation regarding the success rate of tube placement of the different variations of the two types of endotracheal tubes, the correct position and frequency of extubation will be obtained. Correct position will be determined by correlating length and outer diameter of tubes with length and inner diameter of the trachea of different age groups of patient children, percentage of tube tip progression into the trachea and distance of the tube tip to the carina. This will be done through drawback technique and visualized using a flexible video endoscopy. Different measurements will be obtained in varying positions. Frequency of extubation will be computed for each type and brand or internal diameter of the endotracheal tubes examined in different positions and head manipulations. Occurrence of twisting or kinking will be determined as well as the degree of displacements through endoscopy and other available methods. Sealing and leakage will be determined at different pressure levels. Correct position of the tubes will be determined through capnography and auscultation of the lungs. III. Adverse Effects Related to Placement of Endotracheal Tubes In search for any irritation, inflammation and other signs of abnormalities that can lead to subglottic stenosis, regular observation of suspected areas of contact will be implemented. Each patient will be evaluated using endoscopic examinations for any manifestations that can be considered as a reaction to the use of particular size, brand and type of endotracheal tubes. The method of placement and position of the tubes will also be examined for any effect or eventual correlation to symptoms that may or may not develop for each tube type, size and brand. In addition, drastic and repetitive movements of the head and bending of the neck will all be recorded. Occurrence of initial symptoms related to the development of subglottic stenosis will be noted. These include mucosal tissue ischaemia, ulcerations, edema, circular necrosis and postextubation morbidity. IV. Evaluation of Proper Application of Endotracheal Tubes by Nurse Practitioners Selection of appropriate tube size and proper placement by two types of nurse practitioner will also be included in the evaluation of the applicability of the tubes in the above three parts. Nurse practitioners will be divided in two but in randomized trials. The first group will be composed of experienced nurse practitioners who are nurse anesthetists by with greater than one year experience in the practice involving endotracheal tubes. The other group will include the relatively inexperienced practitioners who are student nurse anesthetists. This part will become a factor involving the description, selection, placement and evaluation of success rates and adverse effects of uncuffed and cuffed endotracheal tubes and their variant sizes. Statistical Analysis Data will be collected and presented as mean (SD) and/or median and range deemed necessary (Table 1). Regression models will be calculated for the relationship of the distance of tube tip distance to carina, length of trachea, depth of insertion and age of children. Percentage will be used for success rates and occurrence of side effects. These data will be correlated to the performance of nurse practitioners as two factors in a random complete block design (RCBD) with three replications. Table 1. Sample table of data to be collected showing randomized complete block design with three replications. Experience Level Cuffed/ Uncuffed Age Group Indication Measurements Position Movement Effects Success Rate Remarks (Years) Size Length Depth Symptoms Etiology Percentage Selection Placement Total Nurse anesthetist with greater than one year of experience Cuffed 0-1 1-2 2-4 4-6 6-8 Uncuffed 0-1 1-2 2-4 4-6 6-8 Student nurse anesthetist Cuffed 0-1 1-2 2-4 4-6 6-8 Uncuffed 0-1 1-2 2-4 4-6 6-8 Works Cited Cox, R. G. "Should Cuffed Endotracheal Tubes be Used Routinely in Children" (Editorial) Can. J Anesth. 52.7 (2005) 669-674. Fine, G.F., and L.M. Borland. "The Future of the Cuffed Endotracheal Tube." Pediatric Anesthesia 14 (2004): 38-42. Khine, H.H., Corddry, D.H., R.G., Kettrick et al. "Comparison of Cuffed and Uncuffed Endotracheal Tubes in Young Children During General Anesthesia." Anesthesiology 86 (1997): 627-31. Ho, A. M.-H., Aun, C. S. T. and M. K. Karmakar. "The Margin of Safety Associated with the Use of Cuffed Paediatric Tracheal Tubes." Anaesthesia 57 (2002): 169-182. Newth, C.J., Rachman, B., Patel, N., and J. Hammer. "The Use of Cuffed Versus Uncuffed Endotracheal Tubes in Pediatric Intensive Care." J. Pediatr. 144 (2004): 333-7. Weiss, M., Bernet, V., Stutz, K., Dullenkopf, A., and P. Maino. "Comparison of Cuffed and Uncuffed Preformed Oral Pediatric Tracheal Tubes." Pediatric Anesthesia 16 (2006): 734-742. Weiss, M., Gerber A.C. and A. Dullenkopf. "Appropriate Placement of Intubation Depth Marks in a New Cuffed Paediatric Tracheal Tube." British Journal of Anaesthesia 94.1 (2005): 80-87. Weiss, M., Balmer, C., Dullenkopf, A., et al. "Intubation Depth Markings Allow an Improved Positioning of Endotracheal Tubes in Children." Can. J. Anesth 52 (2005): 721-6. Weiss, M., Dullenkopf, A., Gysin, C., Dillier, C.M. and A.C. Gerber. "Shortcomings of Cuffed Paediatric Tracheal Tubes." British Journal of Anaesthesia 92 (2004): 78-88. Read More