NEONATAL AND PEDIATRIC CUFFED ENDOTRACHEAL TUBES: SAFETY AND PROPER USE

Transcription

1 ENDOTRACHEAL TUBES: SAFETY AND PROPER USE by Esther Weathers RRT, RCP RC Educational Consulting Services, Inc Van Buren Blvd, Suite B, Riverside, CA (800) 441-LUNG / (877) 367-NURS

2 BEHAVIORAL OBJECTIVES UPON COMPLETION OF THE READING MATERIAL, THE PRACTITIONER WILL BE ABLE TO: 1. State why it is desirable to utilize a cuffed endotracheal tube (ETT). 2. Identify a key feature in ensuring cuffed endotracheal tubes are safe to use. 3. Appropriately select the correct size of cuffed endotracheal tube utilizing a proven formula. 4. State why it is imperative that the correct formula be utilized to determine endotracheal tube size. 5. Evaluate the patient immediately after intubation for correct endotracheal tube size by assessment of leak pressures. 6. Estimate the correct endotracheal tube depth by one of two ways, and state which depth will be more accurate. 7. State why the cuff should remain inflated for the duration of intubation. 8. Identify ways in which airway damage could manifest as a result of leaving the cuff deflated. 9. State where cuff pressures should be maintained if tracheal seal is achieved. 10. Identify where cuff pressure will be limited if a tracheal seal is not obtained. 11. Use clinical judgment to determine when an adult range for cuff pressure can be utilized. 12. Briefly describe the benefits of a new endotracheal tube on the market that they may be exposed to in clinical practice. COPYRIGHT 2008 BY RC EDUCATIONAL CONSULTING SERVICES, INC. TX AUTHORED (2008) BY ESTHER WEATHERS, RRT, RCP ALL RIGHTS RESERVED This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 2

3 This course is for reference and education only. Every effort is made to ensure that the clinical principles, procedures and practices are based on current knowledge and state of the art information from acknowledged authorities, text and journals. This information is not intended as a substitution for diagnosis or treatment given in consultation with a qualified health care professional. This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 3

4 TABLE OF CONTENTS INTRODUCTION... 5 THE SAFETY AND PROPER USE OF CUFFED ENDOTRACHEAL TUBES IN PEDIATRICS... 5 WHY USE A CUFFED ENDOTRACHEAL TUBE?... 5 ARE CUFFED ENDOTRACHEAL TUBES SAFE TO USE IN THIS PATIENT POPULATION?... 6 SIZING OF CUFFED ENDOTRACHEAL TUBES... 6 EVALUATING CORRECT ENDOTRACHEAL TUBE SIZE BY ASSESSING LEAK PRESSURE OF THE CUFF... 7 ENDOTRACHEAL TUBE DEPTH... 7 ENDOTRACHEAL TUBE SIZE/DEPTH TABLE... 9 PROPER CARE OF THE CUFFED ENDOTRACHEAL TUBE... 9 PEDIATRIC CUFF PRESSURE WHAT TO LOOK FOR IN THE FUTURE OF THE PEDIATRIC CUFFED ENDOTRACHAEAL TUBES SUMMARY SUGGESTED READING AND REFERENCES This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 4

5 INTRODUCTION Historically, uncuffed endotracheal tube (ETT) have been utilized in neonatal and pediatric critical care. This is due to the immature pediatric airway, with the narrowest portion being sub glottic, at the level of the cricoid ring. In theory, the seal was believed to be obtained at the level of the cricoid cartilage. Yet any clinician who has managed the ventilator of a pediatric patient can attest to the fact that an endotracheal tube leak comes and goes, and often ventilation or oxygenation can be compromised in the presence of a large leak. Recent evidence surrounding ventilator associated pneumonia (VAP) in adult patients advocates the use of a closed, leak free system to minimize the risk of aspiration. Many centers have extrapolated this evidence to use on pediatric patients, though clinical studies are lacking to validate it. Also, volume ventilation for pediatric and neonatal patients is back in vogue, and new generation ventilators are capable of accounting for the endotracheal tube leak to some degree. However, as good as they are, they are often not good enough. Then there is flow trigger and expiratory sensitivity to discuss, not to mention the reliability of the end tidal CO 2 monitor in the presence of endotracheal tube leak. Yes, the clinician can identify many ways in which a leak free system is desirable. Are cuffed endotracheal tubes truly safe for use in the neonatal and pediatric patient population? What about airway damage, proper cuff pressures? This course is designed to answer many of the questions a clinician may have regarding the safety and efficacy of the use of cuffed endotracheal tubes in the pediatric and neonatal patient populations. It summarizes recent evidence and describes the assessment tools the clinician needs to ensure placement of the correct size of cuffed endotracheal tube, as well as ongoing monitoring for continuing safety. THE SAFETY AND PROPER USE OF CUFFED ENDOTRACHEAL TUBES IN PEDIATRICS Why Use A Cuffed Endotracheal Tube? Improved ventilation and oxygenation without an endotracheal tube leak Improved patient/ventilator synchrony Improved reliability of end tidal CO 2 monitors Part of a VAP prevention strategy This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 5

6 Are Cuffed Endotracheal Tubes Safe To Use In This Patient Population? Yes. Cuffed endotracheal tubes can be safely used in neonatal and pediatric patients provided that cuff pressures are kept less than 20 cm H 2 0. This statement was made by the American Heart and Stroke Association (AHA) as part of an evidence based guideline. Sizing Of Cuffed Endotracheal Tubes Proper sizing of cuffed endotracheal tubes differs significantly from sizing of uncuffed endotracheal tubes, as two completely different formulas are used. Uncuffed endotracheal tube size is commonly calculated using the Modified Cole formula, which is 2, 3, 4 : Age in years Cuffed endotracheal tube size should be calculated using the Khine formula, which is 2, 4 : Age in years The Khine formula has been demonstrated to be appropriate for use in 99% of pediatric patients. The evaluation of this formula included consistent factors of leak pressures, the ability to effectively mechanically ventilate, and the incidence of post extubation stridor (PES). It is important that the Khine formula be utilized when determined cuffed endotracheal tube size for two very important reasons: It is imperative that tracheal seal is achieved with the cuff inflated, as damage can occur to the airway from the hard folds and tripod shape of a deflated cuff. The cuff must be kept in the subglottic region. Good tracheal depth of a cuffed endotracheal tube sized using the Cole formula often places the cuff within the vocal cords. Placement of a correctly sized endotracheal tube, even when utilizing the Khine formula, requires that the clinician evaluate the leak pressure to determine cuff pressure value where the leak occurs. This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 6

7 EVALUATING CORRECT ENDOTRACHEAL TUBE SIZE BY ASSESSING LEAK PRESSURE OF THE CUFF The tool of cuff leak pressure assessments can also be used to determine the most appropriate uncuffed endotracheal tube size, if that is the modality your institution most frequently applies. The aim of this section is not to dictate how cuff leak pressure is determined, as department protocols may vary, and no one way has been clearly described in the literature. However, one method will be discussed at the end in the event the clinician is unfamiliar with the procedure. Upsize ETT by one half size if: Downsize ETT by one half size if: Table compiled from Reference 2 Uncuffed Endotracheal Tube Cuffed Endotracheal Tube A leak occurs at < 10 cm H 2 0 A leak occurs at < 10 cm H 2 0 with cuff inflated There is no leak at 25 cm H 2 0, or there is There is resistance to passage resistance to passage of the ETT into the of the ETT into the trachea trachea Cuff leak pressure can be assessed using a bag-valve device that includes a pressure manometer and a stethoscope. The stethoscope is placed over the trachea in the mid neck region, and a manual breath is given. The clinician listens for an air leak past the cuff or cricoid region while simultaneously observing the pressure manometer to determine at what pressure the air leak occurs. If you are not proficient at this procedure, you may find a slight inspiratory hold is necessary to give you more time to assess the cuff leak pressure. Depending on the type of manual resuscitator in use, this leak can also be felt. For example, on a flow inflating bagger of the Jackson-Rees type, the inspiration (manual breath) is more often than not, easily able to be controlled by the operator, as expiration does not occur until the clinician permits it (reservoir closed). The leak pressure can be determined as the pressure, which the clinician feels air passively leaving the reservoir (it will deflate slightly). This should be correlated with the auditory assessment. ENDOTRACHEAL TUBE DEPTH Endotracheal tube depth can be estimated in one of two ways: calculated according to a numerical formula estimated by the intubator utilizing the glottic markings (series of black lines) on the distal end of an uncuffed endotracheal tube. Alternately with the use of a cuffed endotracheal tube, the intubator must ensure the cuff is placed below the vocal cords. There are no depth of insertion formulas that have been clinically validated for use in pediatric patients at this time, all the formulas currently utilized or endorsed in life support text books are This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 7

8 estimates only, and range in accuracy from 81-85%. However, they are more reliable than utilizing the glottic markings, due to age/tracheal length correlations. Meaning, if an endotracheal tube other than what is calculated according to correct formula for age is placed, use of the markers may result in too high or too low endotracheal tube placement in the trachea, or placement of the cuff within the larynx. Use of the Khine formula to select the proper cuffed endotracheal tube size should place the cuff below the vocal cords. The Khine and Cole formulas can also be used to estimate tube depth. Use of a different formula to choose a cuffed endotracheal tube size may still result in an acceptable leak (when performing the secondary assessment of leak pressure to confirm correct endotracheal tube size), but result in cuff placement within the larynx, and the possibility of 10, 11 subsequent damage. Calculation of endotracheal tube depth in patients > 2 years of age can be done by using the formula 4 : Depth ATL (at the lip) = age in years Calculation of endotracheal tube depth for infants up to 2 years of age can be done by using the formula 4 : Depth ATL (at the lip) = Calculated uncuffed endotracheal tube ID x 3 Note: The Modified Cole formula is used to determine uncuffed endotracheal tube ID. Note: Depth ATL (at the lip) calculations are in centimeters. Endotracheal tube depth of insertion formulas have been clinically validated for the neonatal patient population, for patients weighing more than 750 grams up to 4 kilograms 6, 9. Depth ATL (at the lip) = weight (Kg) + 6 This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 8

9 2, 4, 6, 9 Endotracheal Tube Size/Depth Table For your convenience, the following table has been prepared which takes into account the size and depth formulas for endotracheal tubes previously discussed: Gestation Age (w) Weight (Kg) Uncuffed ETT Size Depth (lip) <28 < Age (yr) Cuffed ETT size Uncuffed ETT Size infant older PROPER CARE OF THE CUFFED ENDOTRACHEAL TUBE I t is advisable that the cuff remain inflated for the duration of intubation, as the sharp folds and edges of a deflated cuff (a tripod shape) can cause airway damage. This airway damage can manifest as: formation of granular tissue fibrosis formation of a laryngeal web vocal cord palsy (possibly due to pharyngeal nerve compression) This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 9

10 Proper care of a cuffed endotracheal tube also requires careful attention to cuff pressures. Pediatric Cuff Pressure Safe cuff pressures balance the tracheal perfusion pressure with the pressure needed to create a seal and prevent micro aspiration. Normal capillary perfusion pressure in the adult trachea has been cited to be at and 40 cm H 2 O 17, 19. Recent evidence on VAP suggests higher cuff pressures are more effective at preventing aspiration, and cuff pressures in the range of cm H 2 O have been suggested 20, 21. Neonatal and pediatric tracheal perfusion pressures are unknown, but can be assumed to be lower than adult tracheal perfusion pressures given the lower arterial blood pressures of this patient population 12. So where should pediatric cuff pressures be maintained? Cuff pressures should be kept at < 20 cm H 2 O if tracheal seal is obtained 1 If tracheal seal is not obtained at 20 cm H 2 O, cuff pressures should be limited to 25 cm H 2 O 13 Note: These cuff pressures do not apply to the new generation high volume low pressure (HVLP) cuffed endotracheal tubes, such as the MicroCuff As a clinician, you may ask, when is it safe to utilize adult cuff pressure ranges? Where does the definition of the pediatric patient end? The AHA, in the PALS provider manual used to say that any patient over the age of 8 years of age was considered an adult. That definition has since been changed, the definition of child is now classed from the age of 1 year to signs of puberty. When to utilize adult cuff pressures will be at the discretion of the individual respiratory therapist, a judgment call based on evident signs of puberty and normal arterial blood pressures approaching that of the adult patient 12. WHAT TO LOOK FOR IN THE FUTURE OF PEDIATRIC CUFFED ENDOTRACHEAL TUBES You are now familiar with the pitfalls that can be associated with the use of cuffed endotracheal tubes in pediatric practice, and now know just how important your role is in ensuring they are used safely and appropriately. There is a new endotracheal tube that addresses all these concerns, called the Microcuff endotracheal tube. It was developed by anesthetists after extensive research and review, and recently available for distribution in the United States. It is constructed of improved materials and has a better cuff design. The cuff itself is made of a microthin polyurethane, and is a true HVLP cuff. The cuff is completely flat when deflated, and inflates to an even cylinder shape. This ensures that all of the cuff is in contact with the tracheal wall, and that the cuff pressure is evenly distributed. The cuff seals at an average pressure of 9-15 cm H 2 O 15, which balances the unknowns of pediatric tracheal This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 10

11 perfusion with a good seal. The cuff s placement on the shaft of the endotracheal tube is also lower than conventional cuffs, this decreases the risk of cuff placement within the glottis. Note: This type of cuff is not to be confused with the Tight to Shaft (TTS) cuff currently found on certain Bivona models, which is a high pressure cuff. SUMMARY Cuffed endotracheal tubes are desirable and safe to use in the pediatric patient population, provided they are used appropriately, with care and attention given to proper sizing and assessment of cuff pressures. The American Heart Association gave the use of cuffed endotracheal tubes in hospitalized patients less than 8 years of age (excluding neonates) a IIb classification, which is, Acceptable and Useful, with fair evidence. 16 It behooves the clinician to be familiar with the evidence pertaining to the proper and safe use of cuffed endotracheal tubes, to ensure that airway care is provided according to best practice. This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 11

12 SUGGESTED READING AND REFERENCES 1. American Heart Association (2006) American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) of Pediatric and Neonatal Patients; Pediatric Basic Life Support. Pediatrics, 117; Khine, H.H., et al (1997). Comparison of Cuffed and Uncuffed Endotracheal Tubes in Young Children during General Anesthesia. Anesthesiology. 86;3, Suominen, P., et al (2006). Optimally Fitted Tracheal Tubes Decrease the Probability of Post Extubation Adverse Events in Children Undergoing General Anesthesia. Pediatric Anesthesia 16; Hazinski, M.F., (Ed.) (2002) Textbook of Advanced Pediatric Life Support. American Heart Association. 5. Phipps, L.M., et al (2005) Prospective Assessment of Guidelines for Determining Appropriate Depth of Endotracheal Tube Placement in Children. Pediatric Critical Care Medicine 6;5, Katwinkel, J., (Ed.) (2006) Textbook of Neonatal Resuscitation, 5th Edition. American Heart Association 7. Weiss, M., et al. (2004) Shortcomings of Cuffed Paediatric Tracheal tubes. British Journal of Anesthesiology 92:1, Ho, AMH., Aun, CST., and Karmakar, MK. (2002) The margin of safety associated with the use of cuffed pediatric tracheal tubes. Anesthesia 57; Peterson, J., et al. (2006) Accuracy of the Rule for Endotracheal Tube placement in the neonate. Journal of Perinatology 26; Lute, R. (2005) Accurate Endotracheal Tube Placement in Children: Depth of Insertion is Part of the Process. Pediatric Critical Care Medicine 6:5; Diliier, CM., et al. (2004) Laryngeal Damage due to an unexpectedly large and inappropriately designed cuffed Pediatric tracheal tube in a 13 month old Child. Can J Anesth 51:1; Dullenkopf, A., et al. (2004) Tracheal Sealing of Cuffed Tubes. Pediatric Anesthesia 14; Newth, J.L., et al. (2004) The Use of Cuffed Endo tracheal Tubes in Pediatric Intensive Care. The Journal of Pediatrics, 144; This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 12

13 14. (2005) BLS for Healthcare Providers, Student Manual. American Heart Association. 15. (2007) Microcuff Product Brochure, Kimberly Clark Medical 16. C2005 Evidence Evaluation Template Oct 14, Braz, JRC, et al. (1999) Endotracheal Tube Cuff Pressure: Need for Precise Measurement. Sao Paulo Medical Journal, Vol. 117; No Brimacombe, J., et al. (2002) Large Cuff Volumes Impede Posterior Pharyngeal Mucosal Perfusion with the Laryngeal Tube Airway. Canadian Journal of Anesthesia, 49; Hameed, AA., et al. (2008) Acquired Tracheoesophageal Fistula Due to High Intracuff Pressure. Annals of Thoracic Medicine, 3: Chendrasekhar, A. and Timberlake, GA. Endotracheal Cuff Pressure Threshold for Prevention of Nosocomial Pneumonia. Journal of Applied Research Found on: Kroll, HR. at al. (2006) The Use of Estimation Techniques of Cuff Pressure for Endotracheal Tube Cuff Inflation Is It Safe? American Society of Anesthesiologists, Annual Meeting Abstracts, found on: This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 13

14 POST TEST DIRECTIONS: IF COURSE WAS MAILED TO YOU, CIRCLE THE MOST CORRECT ANSWERS ON THE ANSWER SHEET PROVIDED AND RETURN TO: RCECS, VAN BUREN BLVD, SUITE B, RIVERSIDE, CA OR FAX TO: (951) IF YOU ELECTED ONLINE DELIVERY, COMPLETE THE TEST ONLINE PLEASE DO NOT MAIL OR FAX BACK. 1. Utilizing a cuffed endotracheal tube (ETT) is desirable EXCEPT for the following reason. a. Improved ventilation and oxygenation b. Improved patient/ventilator synchrony c. Part of a VAP prevention strategy to minimize the risk of aspiration d. Minimize damage to vocal cords caused by a leak on expiration 2. According to the American Heart and Stroke Association, cuffed endotracheal tubes can be safely used providing the cuff pressure is kept less than 20 cm H 2 O. a. True b. False 3. Uncuffed endotracheal tube size is commonly calculated using a formula called the Khine formula. a. True b. False 4. You are asked to select the proper size of uncuffed endotracheal tube for a patient who is 5 years old. Which is the proper size? a. 4.0 ID b. 4.5 ID c. 5.0 ID d. 5.5 ID 5. You are asked to select the proper size of cuffed endotracheal tube for a patient who is 3 years old. Which is the proper size? a. 3.5 ID b. 4.0 ID c. 4.5 ID d. 5.0 ID This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 14

15 6. It is important that the Khine formula be used to determine cuffed endotracheal tube size for the following specific reasons: I. the Khine formula is the result of the most recent studies II. tracheal seal will be achieved with the cuff inflated III. The cuff will be placed in the sub glottic region with good tracheal depth IV. The Khine formula places a smaller endotracheal tube than the Cole formula a. all of the above b. I and III c. II and III d. II, III and IV 7. Tracheal placement of a cuffed endotracheal tube has been confirmed in your patient. You inflate the cuff according to your department protocol and the information you have just learned. You assess the patient for a leak and note one to occur at < 10 cm H 2 O. You should: a. Secure the endotracheal tube and note the leak pressure in the patient chart b. Secure the endotracheal tube and tell the attending physician/intubator where the leak occurred. c. Suggest to the attending physician/intubator that the endotracheal tube be upsized by half a size due to the leak d. Secure the endotracheal tube and add more air to the cuff. 8. Pediatric and neonatal endotracheal tube depth cannot be estimated by which of the following ways? a. calculated according to a numerical formula b. ensuring the glottic markings are placed at the vocal cords c. estimating the distance between the nares and the tragus of the ear c. ensuring the cuff is placed below the vocal cords 9. Glottic markings are the most accurate way to estimate endotracheal tube depth of insertion. a. True b. False This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 15

16 10. The endotracheal tube cuff should remain inflated while the patient is intubated to prevent airway damage. This airway damage may manifest in which of the following ways? I. formation of granular tissue II. fibrosis III. formation of a laryngeal web IV. vocal cord palsy a. I and II b. II and IV c. II, III and IV d. all of the above 11. Pediatric cuff pressures should be maintained at < 20 cm H 2 O if tracheal seal is obtained. a. True b. False 12. If tracheal seal is not obtained pediatric cuff pressures should be limited to 30 cm H 2 O. a. True b. False 13. Deciding when to use adult ranges for cuff pressures can be difficult to determine if: a. The child is older than 8 years of age, and evident signs of puberty present b. Evident signs of puberty present, and arterial blood pressures approach that of the adult patient c. Arterial blood pressures approach that of the adult patient, and the doctor wants you to keep the cuff pressures higher as he is worried about VAP d. The doctor wants you to keep the cuff pressures higher as he is worried about VAP, and the patient has a normal blood pressure for their age range 14. The Microcuff endotracheal tube is newly available on the US market. Identify which of the following statements IS NOT a benefit of the Microcuff endotracheal tube. a. the cuff is completely flat when deflated, and inflates to a cylinder shape b. the cuff must be inflated with sterile water c. the cuff seals at an average pressure of 9-15 cm H 2 O d. the placement of the cuff on the shaft of the endotracheal tube is lower than conventional endotracheal tube cuffs This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 16

17 15. There are improvement(s) in pediatric tubes that appear to be on the horizon. I. A better cuff design II. Cuffs will seal with inflation pressures as low as 9-15 cm H 2 O III. Improved material will be used in cuff design IV. Microthin polurethan will be the material used on cuffs in the future a. I and III b. I, II and III c. I, III and IV d. All listed are the improvements that will be made EW: Test Version A This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 17

18 ANSWER SHEET NAME STATE LIC # ADDRESS AARC# (if applic.) DIRECTIONS: (REFER TO THE TEXT IF NECESSARY PASSING SCORE FOR CE CREDIT IS 70%). IF COURSE WAS MAILED TO YOU, CIRCLE THE MOST CORRECT ANSWERS AND RETURN TO: RCECS, VAN BUREN BLVD, SUITE B, RIVERSIDE, CA OR FAX TO: (951) IF YOU ELECTED ONLINE DELIVERY, COMPLETE THE TEST ONLINE PLEASE DO NOT MAIL OR FAX BACK. 1. a b c d 2. a b 3. a b 4. a b c d 5. a b c d 6. a b c d 7. a b c d 8. a b c d 9. a b 10. a b c d 11. a b 12. a b 13. a b c d 14. a b c d 15. a b c d EW: Test Version A This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 18

19 EVALUATION FORM NAME: DATE: AARC # (if applic.) STATE LICENSE #: RC Educational Consulting Services, Inc. wishes to provide our clients with the highest quality CE materials possible. Your honest feedback helps us to continually improve our courses and meet CE regulations in many states. Please complete this form and return/submit it with your answer sheet. Thank you. YES NO Were the objectives of the course met? Was the material clear and understandable? Was the material well-organized? Was the material relevant to your job? Did you learn something new? Was the material interesting? Were the illustrations, if any, helpful? Would you recommend this course to a friend? What was the most valuable portion of the material? What was the least valuable portion of the material? Suggestions for future courses: Comments: What is your specialty area? Credentials? How did you hear about RCECS? This material is copyrighted by RC Educational Consulting Services, Inc. Unauthorized duplication is prohibited by law. 19