- Email: [email protected]
A 12-year experience with prehospital cricothyrotomies
A 12-Year Experience with Prehospital Cricothyrotomies Kenneth J. Robinson, MD, Robert Katz, MD, and Lenworth M. Jacobs, MD
Abstract Introduction: Maintaining cricothyrotomy skills is difficult for air medical crewmembers because the procedure is performed infrequently. The purposes of this study were to review our program’s experience with cricothyrotomies and use this pilot study to guide an industry-wide study. Methods: We conducted a retrospective review of all cricothyrotomies performed by our flight crew during the past 12 years. The flight logs were reviewed for patient demographics, scene information, clinical data, and procedure data. Results: During this period, 8833 patients were transported: 1589 required intubation (18%), and eight of the 1589 required a cricothyrotomy (0.5%). Five nurses (14% of the total employed during the study) and one physician attempted this procedure. All patients had at least one intubation attempt before the cricothyrotomy (average 3.6, range 1-6 attempts). Six (75%) patients had airway edema, four (50%) had an unstable trachea, and one patient (12.5%) had an airway obstruction. Five (62.5%) of the cricothyrotomy attempts were successful. The remaining three patients were managed with bag-valve mask ventilation. Three patients arrived at the receiving hospital with a perfusing rhythm. Conclusion: Cricothyrotomy, rarely performed by our flight crews, is successful in 62.5% of cases. These preliminary data suggest current training practices should be re-evaluated. An industrywide survey is planned to determine the optimal training program.
The first priority in the resuscitation of a critically ill or injured patient is establishing a definitive airway. Flight crews have many techniques by which to secure an airway.1-4 The order in which these techniques are tried are fairly consistent. The first step usually is a noninvasive maneuver, such as a chin lift. Algorithms then progress to more invasive maneuvers, such as endotracheal intubation, a laryngeal mask airway (LMA), or a Combitube®. A surgical airway usually is the last resort.1-4 Prehospital cricothyrotomies are widely reported. We report various operators, indications, and complication rates, but the success rates are uniformly good (86% to 100%).1-8 The purposes of this study were to review our experience with prehospital cricothyrotomies during our 12 years of operation and determine our success rate with this procedure. November-December 2001
Setting LIFE STAR, a two-helicopter air medical transport program based at Hartford Hospital, serves a 150-mile radius of Hartford, Conn. The crew configuration is a pilot, flight nurse, and flight respiratory therapist. The program transports approximately 1200 patients a year, 43% of whom are at scene calls and 57% are interhospital transfers.
Materials and Methods This study was a retrospective review of all patients on whom a prehospital cricothyrotomy was performed by a LIFE STAR crew member between June 1985 and June 1997. Each patient care documentation form was reviewed for age, gender, injury mechanism, number of precricothyrotomy endotracheal intubation (ETT) attempts, indication for cricothyrotomy, precricothyrotomy cardiac rhythm, number of cricothyrotomy attempts, whether the cricothyrotomy was successful, and whether the patient arrived at the receiving hospital with a perfusing rhythm. All cricothyrotomy attempts performed by the crew were included. Patients transported by LIFE STAR who did not receive a cricothyrotomy attempt were not studied. The protocol for airway management was the same in all cases. An ETT was attempted first. The number of preLIFE STAR Helicopter Program, Dept. of EMS/Trauma, Hartford Hospital Integrated Residency in Emergency Medicine, University of Connecticut School of Medicine Address for correspondence: Kenneth J. Robinson, MD, LIFE STAR, Dept. of EMS/Trauma, Hartford Hospital, Hartford, CT 06102 Key words: airway management, air medical transport, cricothyrotomy, prehospital Presented at Air Medical Transport Conference, Albuquerque, N.M., October 1998 Copyright © 2001 by Air Medical Journal Associates 1067-991X/2001/$35.00 + 0 Reprint no. 74/1/120085 doi:10.1067/mmj.2001.120085
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Table 1. Cricothyrotomy Attempts and Success Rates in the Literature Author Erlandson Fortune Jacobson McGill Nugent LIFE STAR
Cric/Total
Success Rate (%)
39/2294 (1.7%) 56/376 (14.9%) 50/509 (9.8%) 38/1407 (2.7%) 55/302 (18.2%) 8/1589 (0.5%)
100 89 94 92 96 62.5
cricothyrotomy ETT attempts depended on the operator’s clinical judgment and the specific situation. If the ETT attempt was unsuccessful, the standard surgical airway approach was used for the cricothyrotomy, a technique involving a longitudinal skin incision made at the level of the cricothyroid membrane. A transverse incision then is made in the cricothyroid membrane. The incision is spread and the largest possible ETT or Shiley tube is inserted in the airway. Proper placement of the tube is confirmed, the tube is secured, and oxygenation and ventilation are accomplished with a bag-valve mask. A successful cricothyrotomy was defined as surgically securing a patent, functioning tube in the lumen of the trachea, irrespective of the number of attempts. The data were analyzed using descriptive statistics, Fisher’s exact test, and Pearson’s chi-squared test to determine significant differences.
Results During the 12-year study period, 8833 patients were transported. A definitive airway was required in 1589 (18%) of these patients. Eight (0.5%) of the 1589 patients required a cricothyrotomy, five (62.5%) of which were successful. Five (14%) of a total of 36 nurses and one physician attempted the procedure. One nurse attempted three cricothyrotomies. In general, the indication for a cricothyrotomy was a failed endotracheal intubation attempt. Seven patients who received a cricothyrotomy were victims of a motor vehicle crash, and one patient was a fall victim. An endotracheal intubation attempt was unsuccessful for one of three reasons: six patients (75%) had airway edema, four (50%) had an unstable trachea, and one (12.5%) had an airway obstruction. All patients had at least one endotracheal intubation attempt before the cricothyrotomy. The average number of precricothyrotomy ETT attempts was 3.6 (range 1-6). Figure 1 breaks down these attempts by patient. The cardiac rhythm was documented for all patients in whom a cricothyrotomy was attempted. Five patients (62.5%) were asystolic, two patients (25%) had sinus bradycardia, and one patient (12.5%) had sinus tachycardia. No successful cricothyrotomy in an asystolic patient changed the rhythm or the patient’s outcome. Three (37.5%) of the eight patients arrived at the receiving hospital with a perfusing rhythm. Of the patients with a perfusing rhythm, two had
28
Figure 1. LIFE STAR precricothyrotomy endotracheal intubation attempts
successful cricothyrotomies. Our rate of attempted cricothyrotomies (0.5%) was compared with other series in the literature (range 1.7% to 18.5%)1,5-7,9 using Pearson chi-squared test and was found to be significantly different (P < 0.001). Our success rate in this series (62.5%) deviated significantly from published series’ rates (82%-100%) (Fisher’s exact test P = 0.017).1,4,5,7-14
Discussion EMS systems and prehospital care vary widely throughout the country. Although each system has several levels of caregivers using different protocols, airway management remains the first priority and often is the most challenging aspect of patient care. In our series, 0.5% of the patients who required a definitive airway had a cricothyrotomy attempt. Compared with other series reported, our rate was the lowest, as shown in Table 1.5-7,9,12 The range was 1.7%9 to 18.2%5. Our success rate was also the lowest reported—62.5%—compared with others5-7,9,12 ranging from 82%13 to 100%.4 This difference was statistically different (P = 0.017). In addition, our series of 1589 patients was one of the largest reported; only one series involved more patients (2294).9 A possible explanation for the low attempt and success rates is that our nurses were confident and successful using a rapid sequence intubation (RSI) for ETT. Since the inception of the program, our flight crew has used RSI. They use the technique with which they are the most comfortable initially and may not progress to a cricothyrotomy soon enough. Another reason so few cricothyrotomies were performed may be the indications used for cricothyrotomy. In general, the only indication for a cricothyrotomy was a failed ETT, the explanations for which were airway edema, unstable trachea, or airway obstruction. For ease of comparison, we grouped all these indications under the category of failed ETT. Other authors reported such indications as facial trauma, clenched teeth, and potential cervical spine injury, as listed in Table 2.1,6-8,13,15 Many groups reported facial trauma as an indication for a cricothyrotomy. In two series this indication
Air Medical Journal 20:6
Table 2. Indications for Cricothyrotomy (Percent of Total) Author Boyle Chang Fortune Jacobson Oliver Spaite LIFE STAR
Facial Trauma 67 17 32 32 63 50 0
Failed ETT
Clenched Teeth
C-Spine
ND ND 9 46 ND ND 0
ND 60 ND ND 18 6 0
20 23 11 ND 50 44 100
ND = no data
Table 3. Precricothyrotomy Endotracheal Intubation Attempts in the Literature Author Erlandson Fortune Jacobson McGill Miklus Nugent Oliver LIFE STAR
Patients with ETT Attempts (%) 18/39 (47) 70/89 (79) 39/50 (78) 33/38 (87) 20/20 (100) 39/55 (71) 50/100 (50) 8/8 (100)
accounted for 63%1 and 67%13 of the cricothyrotomies. In most of these series, the number of patients who had ETT attempts before a cricothyrotomy was unclear. Although a failed ETT attempt was the cricothyrotomy indication in 100% of our cases, the average of the other series reported was 30%.1,6-,8,13,15 In two series the indication for a cricothyrotomy was reported as a failed ETT as low as 11%6 and 20%.1 It was difficult to determine how many precricothyrotomy ETT attempts were made. Clenched teeth were reported as a cricothyrotomy indication in two studies.6,7 In one series, clenched teeth were the indication in 46% of the cases.7 The potential for a cervical spine injury also was reported as an indication. The rate of this indication was 60% in one series.15 The differences between our series and the others reported might be a result of our successful use of RSI and inline stabilization for ETT. Therefore, our only indications for a cricothyrotomy are a failed ETT and massive facial trauma. The rates of precricothyrotomy ETT attempts among published studies (Table 3) is relevant.4-7,9,12,13 In many of the series reported, determining the precricothyrotomy ETT attempt rate was difficult. Every patient in our series who had an attempted cricothyrotomy had at least one precricothyrotomy ETT attempt. Only one other series reported a precricothyroto-
November-December 2001
my ETT rate of 100%.4 In one series, fewer than half of the patients who had a cricothyrotomy had an intubation attempt.9 The average for the series reported was 67%.4-7,9,12,13 The multiple attempts at ETT before cricothyrotomy in our series indicate these airways were difficult to secure. In addition, the multiple attempts at intubation and the complications resulting from those attempts may have distorted the anatomy enough to make the cricothyrotomy more difficult or impossible. Many possible explanations exist for our low success rate. Our nurses are confident with RSI for ETT and may not attempt a cricothyrotomy soon enough. Therefore, they do not become proficient with the procedure. Only five nurses (14%) attempted a cricothyrotomy. The lower success rate also may be the direct result of patient selection. The multiple attempts at intubation indicate these patients had very difficult airways to secure. In addition, the multiple attempts with ETT may have made the cricothyrotomy more difficult or impossible. Although we use the standard surgical approach, newer methods and equipment may enhance this procedure’s success. Lastly, perhaps our training methods affected the success rate. Our nurses initially are trained with didactic sessions and an animal procedure practice lab. They receive recurrent training once a year in a similar procedure practice lab. Many other training modes are available, but the frequency of the recurrent training may be equally important. One series involving flight nurses reported recurrent training once a month and a success rate of 98%.6 A study involving paramedics who received recurrent training every 2 years had a success rate of 89%.6 Our study was limited because it was a retrospective review. We did not review for complications as a result of the procedures, and we did not review or compare injury severity. In addition, our study involving mostly flight nurses using an RSI for ETT was compared with many different levels of operators using various protocols and intubation adjuncts.
Conclusion Prehospital cricothyrotomies have been performed rarely in our program, and we have had a moderate success rate with
29
the procedure. Training modes, training intervals, and airway management protocols may affect success rates. Larger studies are needed to determine whether training affects success rates and outcome.
References 1. Boyle MF, Hatton D, Sheets C. Surgical cricothyrotomy performed by air ambulance flight nurses: a 5-year experience. J Emerg Med 1993;11:41-5. 2. Brofeldt BT, Osborn ML, Sakles JC, Panacek EA. Evaluation of the rapid four-step cricothyrotomy technique: an interim report. Air Med J 1998;17:127-30. 3. Holmes JF, Panacek EA, Sakles JC, Brofeldt BT. Comparison of 2 cricothyrotomy techniques: standard method versus rapid 4-step technique. Ann Emerg Med 1998;32:442-7. 4. Miklus RM, Elliot C, Snow N. Surgical cricothyrotomy in the field: experience of a helicopter transport team. J Trauma 1989;29:506-8. 5. Nugent WL, Rhee KJ, Wisner DH. Can nurses perform cricothyrotomy with acceptable success and complication rates? Ann Emerg Med 1991;20:367-70. 6. Fortune JB, Judkins DG, Scanzaroli D, et al. Efficacy of prehospital surgical cricothyrotomy in trauma patients. J Trauma 1997;42:832-8.
7. Jacobson LE, Gomez GA, Sobieray RJ, et al. Surgical cricothyroidotomy in trauma patients: analysis of its use by paramedics in the field. J Trauma 1996;41:15-20. 8. Spaite DW, Joseph M. Prehospital cricothyrotomy: an investigation of indications, technique, complications, and patient outcome. Ann Emerg Med 1990;19:279-85. 9. Erlandson MJ, Clinton JE, Ruis E, Cohen J. Cricothyrotomy in the emergency department revisited. J Emerg Med 1989;7:115-8. 10. Boyd A, Conlan A. Emergency cricothyrotomy: is its use justified? Surg Rounds 1979;2:19-23. 11. Hawkins ML, Shapiro MB, Cue JI, Wiggins SS. Emergency cricothyrotomy: a reassessment. Am Surg 1995;61:52-5. 12. McGill J, Clinton JE, Ruiz E. Cricothyrotmy in the emergency department. Ann Emerg Med 1982;11:361-4. 13. Oliver R, Rockyvich C, Petersen SR. Prehospital cricothyrotomy in 100 trauma patients. J Trauma 1992;33:159. 14. Xeropotamos NS, Coats TJ, Wilson AW. Prehospital surgical airway management: 1 year’s experience from the helicopter emergency medical service. Injury 1993;24:222. 15. Chang RS, Hamilton RJ, Carter WA. Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training. Acad Emerg Med Mar 1998;5:247-51.
CFRN Examination Review continued from page 16 Answers and Rationale 1. D. Septal wall MI The LAD supplies the anterior, septal, and a small amount of the lateral wall. 2. C. RBBB and second degree Mobitz II LAD supplies the anterior part of the heart, and blockages can cause ischemia and infarction to the bundle branch conduction in the septum. Widening of the QRS can occur and result in more lethal rhythm disturbances or progress to complete heart block. 3. A. Inferior MI Rationale: Inferior: II, III, aVF Lateral: I, aVL Posterior: V1, V2 recipicals Anterior: V1-V4 4. C. I and aVL Reciprocal changes for an inferior MI will be seen in the lateral wall leads I and aVL. 5. C. Increase preload The problem lies in the right side, so clinicians need to increase preload to help get the volume through the right side. doi:10.1067/mmj.2001.120179
30
Air Medical Journal 20:6
Abstract Introduction: Maintaining cricothyrotomy skills is difficult for air medical crewmembers because the procedure is performed infrequently. The purposes of this study were to review our program’s experience with cricothyrotomies and use this pilot study to guide an industry-wide study. Methods: We conducted a retrospective review of all cricothyrotomies performed by our flight crew during the past 12 years. The flight logs were reviewed for patient demographics, scene information, clinical data, and procedure data. Results: During this period, 8833 patients were transported: 1589 required intubation (18%), and eight of the 1589 required a cricothyrotomy (0.5%). Five nurses (14% of the total employed during the study) and one physician attempted this procedure. All patients had at least one intubation attempt before the cricothyrotomy (average 3.6, range 1-6 attempts). Six (75%) patients had airway edema, four (50%) had an unstable trachea, and one patient (12.5%) had an airway obstruction. Five (62.5%) of the cricothyrotomy attempts were successful. The remaining three patients were managed with bag-valve mask ventilation. Three patients arrived at the receiving hospital with a perfusing rhythm. Conclusion: Cricothyrotomy, rarely performed by our flight crews, is successful in 62.5% of cases. These preliminary data suggest current training practices should be re-evaluated. An industrywide survey is planned to determine the optimal training program.
The first priority in the resuscitation of a critically ill or injured patient is establishing a definitive airway. Flight crews have many techniques by which to secure an airway.1-4 The order in which these techniques are tried are fairly consistent. The first step usually is a noninvasive maneuver, such as a chin lift. Algorithms then progress to more invasive maneuvers, such as endotracheal intubation, a laryngeal mask airway (LMA), or a Combitube®. A surgical airway usually is the last resort.1-4 Prehospital cricothyrotomies are widely reported. We report various operators, indications, and complication rates, but the success rates are uniformly good (86% to 100%).1-8 The purposes of this study were to review our experience with prehospital cricothyrotomies during our 12 years of operation and determine our success rate with this procedure. November-December 2001
Setting LIFE STAR, a two-helicopter air medical transport program based at Hartford Hospital, serves a 150-mile radius of Hartford, Conn. The crew configuration is a pilot, flight nurse, and flight respiratory therapist. The program transports approximately 1200 patients a year, 43% of whom are at scene calls and 57% are interhospital transfers.
Materials and Methods This study was a retrospective review of all patients on whom a prehospital cricothyrotomy was performed by a LIFE STAR crew member between June 1985 and June 1997. Each patient care documentation form was reviewed for age, gender, injury mechanism, number of precricothyrotomy endotracheal intubation (ETT) attempts, indication for cricothyrotomy, precricothyrotomy cardiac rhythm, number of cricothyrotomy attempts, whether the cricothyrotomy was successful, and whether the patient arrived at the receiving hospital with a perfusing rhythm. All cricothyrotomy attempts performed by the crew were included. Patients transported by LIFE STAR who did not receive a cricothyrotomy attempt were not studied. The protocol for airway management was the same in all cases. An ETT was attempted first. The number of preLIFE STAR Helicopter Program, Dept. of EMS/Trauma, Hartford Hospital Integrated Residency in Emergency Medicine, University of Connecticut School of Medicine Address for correspondence: Kenneth J. Robinson, MD, LIFE STAR, Dept. of EMS/Trauma, Hartford Hospital, Hartford, CT 06102 Key words: airway management, air medical transport, cricothyrotomy, prehospital Presented at Air Medical Transport Conference, Albuquerque, N.M., October 1998 Copyright © 2001 by Air Medical Journal Associates 1067-991X/2001/$35.00 + 0 Reprint no. 74/1/120085 doi:10.1067/mmj.2001.120085
27
Table 1. Cricothyrotomy Attempts and Success Rates in the Literature Author Erlandson Fortune Jacobson McGill Nugent LIFE STAR
Cric/Total
Success Rate (%)
39/2294 (1.7%) 56/376 (14.9%) 50/509 (9.8%) 38/1407 (2.7%) 55/302 (18.2%) 8/1589 (0.5%)
100 89 94 92 96 62.5
cricothyrotomy ETT attempts depended on the operator’s clinical judgment and the specific situation. If the ETT attempt was unsuccessful, the standard surgical airway approach was used for the cricothyrotomy, a technique involving a longitudinal skin incision made at the level of the cricothyroid membrane. A transverse incision then is made in the cricothyroid membrane. The incision is spread and the largest possible ETT or Shiley tube is inserted in the airway. Proper placement of the tube is confirmed, the tube is secured, and oxygenation and ventilation are accomplished with a bag-valve mask. A successful cricothyrotomy was defined as surgically securing a patent, functioning tube in the lumen of the trachea, irrespective of the number of attempts. The data were analyzed using descriptive statistics, Fisher’s exact test, and Pearson’s chi-squared test to determine significant differences.
Results During the 12-year study period, 8833 patients were transported. A definitive airway was required in 1589 (18%) of these patients. Eight (0.5%) of the 1589 patients required a cricothyrotomy, five (62.5%) of which were successful. Five (14%) of a total of 36 nurses and one physician attempted the procedure. One nurse attempted three cricothyrotomies. In general, the indication for a cricothyrotomy was a failed endotracheal intubation attempt. Seven patients who received a cricothyrotomy were victims of a motor vehicle crash, and one patient was a fall victim. An endotracheal intubation attempt was unsuccessful for one of three reasons: six patients (75%) had airway edema, four (50%) had an unstable trachea, and one (12.5%) had an airway obstruction. All patients had at least one endotracheal intubation attempt before the cricothyrotomy. The average number of precricothyrotomy ETT attempts was 3.6 (range 1-6). Figure 1 breaks down these attempts by patient. The cardiac rhythm was documented for all patients in whom a cricothyrotomy was attempted. Five patients (62.5%) were asystolic, two patients (25%) had sinus bradycardia, and one patient (12.5%) had sinus tachycardia. No successful cricothyrotomy in an asystolic patient changed the rhythm or the patient’s outcome. Three (37.5%) of the eight patients arrived at the receiving hospital with a perfusing rhythm. Of the patients with a perfusing rhythm, two had
28
Figure 1. LIFE STAR precricothyrotomy endotracheal intubation attempts
successful cricothyrotomies. Our rate of attempted cricothyrotomies (0.5%) was compared with other series in the literature (range 1.7% to 18.5%)1,5-7,9 using Pearson chi-squared test and was found to be significantly different (P < 0.001). Our success rate in this series (62.5%) deviated significantly from published series’ rates (82%-100%) (Fisher’s exact test P = 0.017).1,4,5,7-14
Discussion EMS systems and prehospital care vary widely throughout the country. Although each system has several levels of caregivers using different protocols, airway management remains the first priority and often is the most challenging aspect of patient care. In our series, 0.5% of the patients who required a definitive airway had a cricothyrotomy attempt. Compared with other series reported, our rate was the lowest, as shown in Table 1.5-7,9,12 The range was 1.7%9 to 18.2%5. Our success rate was also the lowest reported—62.5%—compared with others5-7,9,12 ranging from 82%13 to 100%.4 This difference was statistically different (P = 0.017). In addition, our series of 1589 patients was one of the largest reported; only one series involved more patients (2294).9 A possible explanation for the low attempt and success rates is that our nurses were confident and successful using a rapid sequence intubation (RSI) for ETT. Since the inception of the program, our flight crew has used RSI. They use the technique with which they are the most comfortable initially and may not progress to a cricothyrotomy soon enough. Another reason so few cricothyrotomies were performed may be the indications used for cricothyrotomy. In general, the only indication for a cricothyrotomy was a failed ETT, the explanations for which were airway edema, unstable trachea, or airway obstruction. For ease of comparison, we grouped all these indications under the category of failed ETT. Other authors reported such indications as facial trauma, clenched teeth, and potential cervical spine injury, as listed in Table 2.1,6-8,13,15 Many groups reported facial trauma as an indication for a cricothyrotomy. In two series this indication
Air Medical Journal 20:6
Table 2. Indications for Cricothyrotomy (Percent of Total) Author Boyle Chang Fortune Jacobson Oliver Spaite LIFE STAR
Facial Trauma 67 17 32 32 63 50 0
Failed ETT
Clenched Teeth
C-Spine
ND ND 9 46 ND ND 0
ND 60 ND ND 18 6 0
20 23 11 ND 50 44 100
ND = no data
Table 3. Precricothyrotomy Endotracheal Intubation Attempts in the Literature Author Erlandson Fortune Jacobson McGill Miklus Nugent Oliver LIFE STAR
Patients with ETT Attempts (%) 18/39 (47) 70/89 (79) 39/50 (78) 33/38 (87) 20/20 (100) 39/55 (71) 50/100 (50) 8/8 (100)
accounted for 63%1 and 67%13 of the cricothyrotomies. In most of these series, the number of patients who had ETT attempts before a cricothyrotomy was unclear. Although a failed ETT attempt was the cricothyrotomy indication in 100% of our cases, the average of the other series reported was 30%.1,6-,8,13,15 In two series the indication for a cricothyrotomy was reported as a failed ETT as low as 11%6 and 20%.1 It was difficult to determine how many precricothyrotomy ETT attempts were made. Clenched teeth were reported as a cricothyrotomy indication in two studies.6,7 In one series, clenched teeth were the indication in 46% of the cases.7 The potential for a cervical spine injury also was reported as an indication. The rate of this indication was 60% in one series.15 The differences between our series and the others reported might be a result of our successful use of RSI and inline stabilization for ETT. Therefore, our only indications for a cricothyrotomy are a failed ETT and massive facial trauma. The rates of precricothyrotomy ETT attempts among published studies (Table 3) is relevant.4-7,9,12,13 In many of the series reported, determining the precricothyrotomy ETT attempt rate was difficult. Every patient in our series who had an attempted cricothyrotomy had at least one precricothyrotomy ETT attempt. Only one other series reported a precricothyroto-
November-December 2001
my ETT rate of 100%.4 In one series, fewer than half of the patients who had a cricothyrotomy had an intubation attempt.9 The average for the series reported was 67%.4-7,9,12,13 The multiple attempts at ETT before cricothyrotomy in our series indicate these airways were difficult to secure. In addition, the multiple attempts at intubation and the complications resulting from those attempts may have distorted the anatomy enough to make the cricothyrotomy more difficult or impossible. Many possible explanations exist for our low success rate. Our nurses are confident with RSI for ETT and may not attempt a cricothyrotomy soon enough. Therefore, they do not become proficient with the procedure. Only five nurses (14%) attempted a cricothyrotomy. The lower success rate also may be the direct result of patient selection. The multiple attempts at intubation indicate these patients had very difficult airways to secure. In addition, the multiple attempts with ETT may have made the cricothyrotomy more difficult or impossible. Although we use the standard surgical approach, newer methods and equipment may enhance this procedure’s success. Lastly, perhaps our training methods affected the success rate. Our nurses initially are trained with didactic sessions and an animal procedure practice lab. They receive recurrent training once a year in a similar procedure practice lab. Many other training modes are available, but the frequency of the recurrent training may be equally important. One series involving flight nurses reported recurrent training once a month and a success rate of 98%.6 A study involving paramedics who received recurrent training every 2 years had a success rate of 89%.6 Our study was limited because it was a retrospective review. We did not review for complications as a result of the procedures, and we did not review or compare injury severity. In addition, our study involving mostly flight nurses using an RSI for ETT was compared with many different levels of operators using various protocols and intubation adjuncts.
Conclusion Prehospital cricothyrotomies have been performed rarely in our program, and we have had a moderate success rate with
29
the procedure. Training modes, training intervals, and airway management protocols may affect success rates. Larger studies are needed to determine whether training affects success rates and outcome.
References 1. Boyle MF, Hatton D, Sheets C. Surgical cricothyrotomy performed by air ambulance flight nurses: a 5-year experience. J Emerg Med 1993;11:41-5. 2. Brofeldt BT, Osborn ML, Sakles JC, Panacek EA. Evaluation of the rapid four-step cricothyrotomy technique: an interim report. Air Med J 1998;17:127-30. 3. Holmes JF, Panacek EA, Sakles JC, Brofeldt BT. Comparison of 2 cricothyrotomy techniques: standard method versus rapid 4-step technique. Ann Emerg Med 1998;32:442-7. 4. Miklus RM, Elliot C, Snow N. Surgical cricothyrotomy in the field: experience of a helicopter transport team. J Trauma 1989;29:506-8. 5. Nugent WL, Rhee KJ, Wisner DH. Can nurses perform cricothyrotomy with acceptable success and complication rates? Ann Emerg Med 1991;20:367-70. 6. Fortune JB, Judkins DG, Scanzaroli D, et al. Efficacy of prehospital surgical cricothyrotomy in trauma patients. J Trauma 1997;42:832-8.
7. Jacobson LE, Gomez GA, Sobieray RJ, et al. Surgical cricothyroidotomy in trauma patients: analysis of its use by paramedics in the field. J Trauma 1996;41:15-20. 8. Spaite DW, Joseph M. Prehospital cricothyrotomy: an investigation of indications, technique, complications, and patient outcome. Ann Emerg Med 1990;19:279-85. 9. Erlandson MJ, Clinton JE, Ruis E, Cohen J. Cricothyrotomy in the emergency department revisited. J Emerg Med 1989;7:115-8. 10. Boyd A, Conlan A. Emergency cricothyrotomy: is its use justified? Surg Rounds 1979;2:19-23. 11. Hawkins ML, Shapiro MB, Cue JI, Wiggins SS. Emergency cricothyrotomy: a reassessment. Am Surg 1995;61:52-5. 12. McGill J, Clinton JE, Ruiz E. Cricothyrotmy in the emergency department. Ann Emerg Med 1982;11:361-4. 13. Oliver R, Rockyvich C, Petersen SR. Prehospital cricothyrotomy in 100 trauma patients. J Trauma 1992;33:159. 14. Xeropotamos NS, Coats TJ, Wilson AW. Prehospital surgical airway management: 1 year’s experience from the helicopter emergency medical service. Injury 1993;24:222. 15. Chang RS, Hamilton RJ, Carter WA. Declining rate of cricothyrotomy in trauma patients with an emergency medicine residency: implications for skills training. Acad Emerg Med Mar 1998;5:247-51.
CFRN Examination Review continued from page 16 Answers and Rationale 1. D. Septal wall MI The LAD supplies the anterior, septal, and a small amount of the lateral wall. 2. C. RBBB and second degree Mobitz II LAD supplies the anterior part of the heart, and blockages can cause ischemia and infarction to the bundle branch conduction in the septum. Widening of the QRS can occur and result in more lethal rhythm disturbances or progress to complete heart block. 3. A. Inferior MI Rationale: Inferior: II, III, aVF Lateral: I, aVL Posterior: V1, V2 recipicals Anterior: V1-V4 4. C. I and aVL Reciprocal changes for an inferior MI will be seen in the lateral wall leads I and aVL. 5. C. Increase preload The problem lies in the right side, so clinicians need to increase preload to help get the volume through the right side. doi:10.1067/mmj.2001.120179
30
Air Medical Journal 20:6