Combitube Insertion Research Articles

Hemodynamic responses to insertion of the laryngeal mask airway versus Combitube

Introduction: One of the most common problems during laryngoscopy involves sympathetic system stimulation and the subsequent hemodynamic changes. It is a key measure to maintain the hemodynamic stability of patients with cardiovascular diseases during induction of anesthesia. This study attempted to compare the hemodynamic effects of laryngeal mask airway and combitube. Methods: This prospective clinical trial was conducted on a total of 142 candidate patients 18 to 60 years of age with ASA I and II undergoing elective surgery. Patients were randomly divided into three groups: (1) mask ventilation (control group) (2) laryngeal mask airway and (3) combitube. At the next stage, the systolic and diastolic blood pressures and heart rates were measured at the following points in time: baseline, after induction of anesthesia and before airway manipulation, 1, 3 and 5 minutes after ventilation. The findings were analyzed and P<0.05 was considered significant. Correspondence: Hashem Jarineshin, MD. Anesthesiology, Critical Care and Pain Management Research Center, Hormozgan University of Medical Sciences. Bandar Abbas, Iran Tel:+98 9173613464 Email: hjarineshin@yahoo.com Results: Patients in all three groups were closely matched in terms of age, height, weight, sex and Mallampati score. The duration of combitube insertion was significantly longer than that of laryngeal mask airway (LMA) (P<0.05). The baseline and post-induction hemodynamic variables were similar in the three groups. The hemodynamic variations at the first minute were higher in the combitube group than the other two. At minute 3, the hemodynamic parameters in Groups 2 and 3 were significantly higher than those in Group 1. Moreover, diastolic blood pressure in Groups 2 and 3 was higher than that in Group 1 in the 5th minute. Conclusion: LMA insertion leads to lower hemodynamic responses in patients during airway management compared to combitube. This is can be an important issue in cardiovascular patients.

Differential Diagnosis Cyanosis Versus Argyria: When Your Patient Remains Blue—A 48-year-old Trauma Patient With Persistent Cyanosis

A 48-year-old man presented to the emergency department after a motorcycle-versus-car collision during which he was ejected from his bike. At the scene, the man was initially alert but had marked cyanosis; he then lost consciousness and exhibited generalized seizure activity. Paramedics attempted rapid-sequence induction intubation but could not place an endotracheal (ET) tube, so they resorted to Combitube (Tyco-Kendall, Mansfield, MA) insertion. Because breath sounds were decreased on the right side, needle decompression was performed to relieve a possible tension pneumothorax.

Evaluation of a Combat Medic Skills Validation Test

The purpose of this study was to describe validity and reliability of a skills-based test (the Semi-Annual Combat Medic Skills-Validation Test) used by the Army to determine combat medic competency. An instrumentation design was used in which a panel of experts completed a content validity index on all skills. Simulation testing was used to determine criterion validity, intrarater, interrater, and test-retest reliability. Findings revealed that needle chest decompression, Combitube insertion, and automatic external defibrillator were the only skills with low validity (content validity index < or = 0.75). Splinting was recommended as an addition to the skill test. The validity criterion of a modified postcourse Emergency Medical Technician-Basic examination score was significantly related to the Semi-Annual Combat Medic Skills-Validation Test scores (r = 0.409, p = 0.006, two tailed). There was high intra- and interrater agreement on performance steps and skills. Higher subject scores were seen on the medical skills than on the trauma skills. When retested, there was significant improvement (t = 3.268, df = 7, p < 0.014, two tailed).

Does the type of out-of-hospital airway interfere with other cardiopulmonary resuscitation tasks?

Out-of-hospital rescuers often perform tracheal intubation (TI) prior to other cardiopulmonary resuscitation (CPR) interventions. TI is a complex and error-prone procedure that may interfere with other key resuscitation tasks. We compared the effects of TI versus esophageal tracheal combitube (ETC) insertion on the accomplishment of other interventions during simulated cardiopulmonary resuscitation. In this prospective trial using a human simulator, two-paramedic teams simulated resuscitation of a ventricular fibrillation cardiopulmonary arrest using standard Advanced Cardiac Life Support guidelines. In each of two trials, teams used either TI or ETC as the primary airway device. Following delivery of three rescue shocks, we measured time intervals to successful airway placement, intravenous (IV) line insertion, drug administration, delivery of fourth rescue shock and completion of all four tasks. We also measured the total time without chest compressions. We compared task completion times using non-parametric statistics (Wilcoxon signed-ranks test) with a Bonferroni-adjusted p-value of 0.008. Twenty teams each completed two scenarios. Participants required a median of 172.5 s (IQR: 146.5-225.5) to accomplish all four tasks. Elapsed time to airway placement was significantly less for ETC than TI (median difference 26.5 s (IQR 13-44.5), p=0.002). Time without chest compressions was less for ETC than TI (median difference 8.5 s (IQR 2.5-23.5), p=0.005). There were no differences between ETC and TI in times to IV placement (median difference 23.5 s (IQR -20 to 61), p=0.11), drug delivery (39.5 s (IQR -18 to 63), p=0.07), delivery of fourth rescue shock (39.5 s (IQR -21.5 to 87.5), p=0.07) or completion of all four tasks (33 s (IQR -11 to 74.5), p=0.08). Compared with TI, ETC reduced time to airway placement and time without chest compressions, but did not affect elapsed times to accomplish other interventions. Additional time differences may be realized if translated to clinical out-of-hospital conditions.

Prehospital airway management: A prospective evaluation of anaesthesia trained emergency physicians

To determine the characteristics of prehospital tracheal intubation and the incidence of difficult-to-manage airways in out-of-hospital patients managed by emergency medicine physicians with anaesthesia training. In a prospective study, conducted over a 4-year period, we evaluated all airway interventions performed by anaesthesia-trained emergency physicians. One thousand, one hundred and six out of 16,559 patients (6.8%) required tracheal intubation. Orotracheal intubation was attempted in 982, laryngoscopic aided nasotracheal intubation in 64 and blind nasotracheal intubation in 90 of the cases. Two techniques were used in 30 patients. Failure rates were 2.4, 8.1 and 25.6%, respectively. A Combitube or LMA was used in 2.0%. In one case of failed Combitube insertion successful needle cricothyrotomy was performed. In patients undergoing direct laryngoscopy, Cormack-Lehane laryngeal grade views I-IV were seen in 52.0, 28.8, 12.6 and 6.6% of cases, respectively. A difficult to manage airway (DMA) was reported in 14.8%, multiple intubation attempts in 4.3% and failed intubation in 2.0% of all cases. Grouping patients based on clinical presentation revealed a significantly higher incidence of DMA in trauma patients (18.6%) and during cardiopulmonary resuscitation (16.7%) than in the remaining patient group (9.8%). Intubation failed significantly more often in trauma (3.9%) than in the remaining patient group (1.1%). When compared to studies on laryngoscopy performed in the operating room, this study demonstrated a higher incidence of difficult and failed laryngoscopy, DAM, and high laryngeal grade views when patients were managed in a prehospital setting by anaesthesia trained physicians.

Success and Complication Rates with Prehospital Placement of an Esophageal-Tracheal Combitube as a Rescue Airway

Previous studies have proven the success of the Esophageal-Tracheal Combitube (ETC) as a primary airway, but not as a rescue airway. The object of this study was to observe success and complication rates of paramedic placement of an ETC as a rescue airway, and to compare success rates with endotracheal tube (ETT) intubation. The primary outcome indicator was placement with successful ventilation. Complication rates, esophageal placement, and return of spontaneous circulation (ROSC) were secondary measures. A retrospective review of the records of patients who had ETC attempts by Emergency Medical Services (EMS) was conducted for a period of three years. Complications were defined a priori. The ETC is used primarily as rescue airway for a failed attempt at an endotracheal tube (ETT) intubation. A control group for ETT placements was drawn from the EMS quality assurance (QA) database for the same period. Esophageal-Tracheal Combitube insertion was attempted on 162 patients, of which, 113 (70%) were successful, 46 (28%) failed, and the outcome of three (2%) was not recorded. Inability to place the ETC occurred in 29 (18%) patients, and accounted for 48% (22/46) of failures. The use of the ETC caused dental trauma in one patient, and one placement of the ETC was related to the onset of subcutaneous emphysema. Blood in the ETC from active upper gatrointestinal bleeding occurred in nine patients (6%), and four tubes (3%) became dislodged en route to the hospital. The apriori complication rate was 44/162 (27%). Inability to determine placement of the ETC due to emesis from both ports occurred in 21 cases. Combining these problems with the apriori complications, the overall rate was 40% (65/162). Esophageal-Tracheal Combitube location was noted in a subset of 90 charts, of which, 76 (84%) were esophageal, and 14 (16%) were tracheal. Thirteen of 126 (10%) patients in cardiac arrest had return of spontaneous circulation (ROSC) in the field after placement of the ETC. An ETT was attempted in 128 control patients, of which, 107 (84%) were successful, 21 (16%) failed (odds ratio (OR) for ETT vs. ETC = 2.1; 95% CI = 1.12-3.86). Despite a low ROSC rate, the complication and success rates of ETC are acceptable for a rescue airway device. Tracheal placement of the Combitube is uncommon, but requires fail-safe discrimination. Similar to previous reports, the success ratio for ETT was greater than for the ETC.

Part 4: Advanced Life Support

The topics reviewed by the International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force are grouped as follows: (1) causes and prevention, (2) airway and ventilation, (3) drugs and fluids given during cardiac arrest, (4) techniques and devices to monitor and assist the circulation, (5) periarrest arrhythmias, (6) cardiac arrest in special circumstances, (7) postresuscitation care, and (8) prognostication. Defibrillation topics are discussed in Part 3. The most important developments in advanced life support (ALS) since the last ILCOR review in 2000 include For many topics there were insufficient data with which to make firm treatment recommendations. The following interventions in particular need further research: Rescuers may be able to identify some noncardiac causes of arrest and tailor the sequence of attempted resuscitation. Most patients sustaining in-hospital cardiac arrest display signs of deterioration for several hours before the arrest. Early identification of these high-risk patients and the immediate arrival of …

Alternative management techniques for the difficult airway: esophageal-tracheal Combitube

To summarize knowledge about the esophageal-tracheal Combitube in emergency medicine and anesthesia, with special emphasis on uncommon indications. Papers published between August 2003 and July 2004 are reviewed. Tracheal intubation in the field is difficult and success rates are dependent upon training level (90-98%). Therefore, the esophageal-tracheal Combitube has been recommended for emergency ventilation after failed tracheal intubation with success rates of about 90%, even when performed by emergency medical technicians. Combitube insertion is easy to learn, but practice is necessary to retain skills. Use of this device has also been recommended for ventilatory support during routine anesthesia. Combitube ventilation is successful in over 96% of patients, with minimal trauma. Since only a small percentage of American anesthesiologists are familiar with the Combitube (<50%), using the device in anesthesia care may improve the skills required during emergency airway management. Blood gases are in the range of those obtained during endotracheal tube ventilation and aspiration prophylaxis is at least as good as that of the laryngeal mask airway. Successful uncommon uses of the device have also been recommended, for example, Combitube ventilation in craniomaxillomandibular surgery via the submental route and insertion of the device in a burns patient with minimal mouth opening and significant tracheal stenosis after long-term ventilation. The esophageal-tracheal Combitube is a useful and efficient alternative airway characterized by high success rates in emergency situations. We recommend the use of a laryngoscope for insertion and strict adherence to the manufacturer's guidelines in order to maximize success and minimize potential injury.

Intracranial pressure and hemodynamic responses to esophageal tracheal combitube insertion

Study objectives: Laryngotracheal stimulation is known to increase intracranial pressure (ICP) during intubation. The esophageal-tracheal twin-lumen airway device (Combitube) is a commonly used adjunct airway device that is blindly inserted, usually in the esophagus, thus avoiding the laryngotracheal stimulation caused by endotracheal tube placement. Previous work from our laboratory has established a swine model to measure the intracranial effects of rapid sequence intubation (RSI). We used this model to evaluate the effects of Combitube insertion and balloon inflation on ICP and hemodynamics. Methods: Five adult swine (45 to 60 kg) were instrumented under isoflurane anesthesia. Measurements included ICP measured by a fiberoptic intraparenchymal catheter and invasive arterial blood pressure. A Combitube airway was inserted. ICP and hemodynamic measurements were continually recorded at baseline, during airway insertion and balloon inflation, and for 5 additional minutes. Results: Mean baseline ICP was 10 mm Hg (range 8 to 15 mm Hg). Changes in ICP were minimal, with mean values remaining within 1 mm Hg of baseline values throughout the protocol. Hemodynamic effects were also minimal. Baseline mean arterial pressure was 94 mm Hg (range 66 to 133 mm Hg), with mean values remaining within 5 mm Hg throughout the protocol. Conclusion: The model shows minimal ICP and hemodynamic effects associated with Combitube insertion and balloon inflation. Although limited by small sample size and the setting of an anesthetized animal, these data reinforce the hypothesis that Combitube use is unlikely to have deleterious effects on ICP. Future investigations should directly compare Combitube insertion to endotracheal intubation, with the addition of head injury pathology. Study objectives: Laryngotracheal stimulation is known to increase intracranial pressure (ICP) during intubation. The esophageal-tracheal twin-lumen airway device (Combitube) is a commonly used adjunct airway device that is blindly inserted, usually in the esophagus, thus avoiding the laryngotracheal stimulation caused by endotracheal tube placement. Previous work from our laboratory has established a swine model to measure the intracranial effects of rapid sequence intubation (RSI). We used this model to evaluate the effects of Combitube insertion and balloon inflation on ICP and hemodynamics. Methods: Five adult swine (45 to 60 kg) were instrumented under isoflurane anesthesia. Measurements included ICP measured by a fiberoptic intraparenchymal catheter and invasive arterial blood pressure. A Combitube airway was inserted. ICP and hemodynamic measurements were continually recorded at baseline, during airway insertion and balloon inflation, and for 5 additional minutes. Results: Mean baseline ICP was 10 mm Hg (range 8 to 15 mm Hg). Changes in ICP were minimal, with mean values remaining within 1 mm Hg of baseline values throughout the protocol. Hemodynamic effects were also minimal. Baseline mean arterial pressure was 94 mm Hg (range 66 to 133 mm Hg), with mean values remaining within 5 mm Hg throughout the protocol. Conclusion: The model shows minimal ICP and hemodynamic effects associated with Combitube insertion and balloon inflation. Although limited by small sample size and the setting of an anesthetized animal, these data reinforce the hypothesis that Combitube use is unlikely to have deleterious effects on ICP. Future investigations should directly compare Combitube insertion to endotracheal intubation, with the addition of head injury pathology.

The use of quantitative end-tidal capnometry to avoid inadvertent severe hyperventilation in patients with head injury after paramedic rapid sequence intubation.

This study aimed to determine whether field end-tidal carbon dioxide CO2 (ETCO2) monitoring decreases inadvertent severe hyperventilation after paramedic rapid sequence intubation. Data were collected prospectively as part of the San Diego Paramedic Rapid Sequence Intubation Trial, which enrolled adults with severe head injuries (Glasgow Coma Score, 3-8) that could not be intubated without neuromuscular blockade. After preoxygenation, the patients underwent rapid sequence intubation using midazolam and succinylcholine. A maximum of three intubation attempts were allowed before Combitube insertion was mandated. Tube confirmation was accomplished by physical examination, qualitative capnometry, pulse oximetry, and syringe aspiration. Standard ventilation parameters (tidal volume, 800 mL; 12 breaths/minute) were taught. One agency used portable ETCO2 monitors, with ventilation modified to target ETCO2 values of 30 to 35 mm Hg. Trial patients transported by aeromedical crews also underwent ETCO2 monitoring. The primary outcome measure was the incidence of inadvertent severe hyperventilation, defined as arterial blood gas partial pressure of CO2 (pCO2) of less than 25 mm Hg at arrival, for patients with and those without ETCO2 monitoring. These groups also were compared in terms of age, gender, clinical presentation, Abbreviated Injury Score, Injury Severity Score, arrival arterial blood gas data, and survival. The study enrolled 426 patients and administered neuromuscular blocking agents to 418 patients. Endotracheal intubation was successful for 355 of these patients (85.2%). Another 58 patients (13.6%) underwent Combitube insertion. For 291 successfully intubated patients, arrival pCO2 values were documented, with continuous ETCO2 monitoring performed for 144 of these patients (49.4%). Patients with ETCO2 monitoring had a lower incidence of inadvertent severe hyperventilation than those without ETCO2 monitoring (5.6% vs. 13.4%; odds ratio, 2.64; 95% confidence interval, 1.12-6.20; p = 0.035). There were no significant differences in terms of age, gender, clinical presentation, Abbreviated Injury Score, Injury Severity Score, arrival partial pressure of oxygen (PO2) and pH, or survival. The patients in both groups with severe hyperventilation had a significantly higher mortality rate than the patients without hyperventilation (56 vs. 30%; odds ratio, 2.9; 95% confidence interval, 1.3-6.6; p = 0.016), which could not be explained solely on the basis of their injuries. The use of ETCO2 monitoring is associated with a decrease in inadvertent severe hyperventilation.

Endotracheal intubation and esophageal tracheal combitube insertion by regular ambulance attendants:: A comparative trial

Objective Recent cardiac arrest resuscitation guidelines have recommended the esophageal tracheal Combitube (ETC) as an advanced airway management alternative for individuals who infrequently perform endotracheal intubation (ETI). This study attempted to analyze basic (nonparamedic) ambulance attendant success rates at ETI and ETC insertion as well as their continuing skill competency over time and whether ongoing practice on mannequins improved skill performance. Methods Three hundred fifty-seven adult patients in cardiorespiratory arrest were treated by 81 basic ambulance attendants. Original study design called for the analysis of two treatment options in three patient groups: ETC insertion, ETI insertion with mannequin practice (ETI-MP), and ETI insertion without mannequin practice (ETI-NMP). The main outcome measures were: (1) successful insertion and ventilation with ETC or ETI, assessed by receiving physicians; and (2) differences in successful insertion/ventilation between the MP and NMP groups. Results Successful insertion (intent-to-treat) for the ETI-NMP group was 70 of 111 (63%; 95% confidence interval [CI], 54–73%); ETI-MP success was 105 of 139 (76%; 95% CI, 67–84%); ETC-NMP success was 26 of 42 (62%; 95% CI, 49–75%); and ETC-MP success was 36 of 53 (68%; 95% CI, 54–82%). Continuing mannequin practice appeared to improve ETI success (as-treated): MP 75% versus NMP 61% (odds ratio, 2.1; 95% CI, 1.11–3.94). Conclusions There were similar rates of successful insertion/ventilation with the ETC and ETI. ETI insertion success was lower without mannequin practice. ETI skill erosion was partially mitigated by additional field experience.

The Combitube as a salvage airway device for paramedic rapid sequence intubation

Study objective The safety of out-of-hospital rapid sequence intubation depends on a reliable strategy when orotracheal intubation is unsuccessful. Here we describe our experience with the Combitube (esophageal-tracheal twin-lumen airway device) as a salvage airway device for paramedic rapid sequence intubation. Methods The San Diego Paramedic Rapid Sequence Intubation Trial was performed to assess the effect of paramedic rapid sequence intubation on outcome in severely head-injured patients. Adults with severe head trauma (Glasgow Coma Scale score 3 to 8) who were unable to be intubated without medications were enrolled. Midazolam and succinylcholine were administered, and paramedics were allowed a maximum of 3 attempts at orotracheal intubation. If the attempts were unsuccessful, Combitube insertion was mandated. After confirmation of tube position, rocuronium was given and standard ventilation protocols were used. The primary outcome measure for this analysis was the success rate for Combitube insertion after unsuccessful orotracheal intubation. In addition, Combitube insertion and orotracheal intubation patients were compared with regard to demographic, clinical, and outcome data. Results A total of 426 patients were enrolled in the trial, with 420 meeting inclusion criteria for this analysis. Orotracheal intubation was successful in 355 (84.5%) of 420; Combitube insertion was successful in 58 (95.1%) of 61 attempts, with no reported complications. Patients undergoing Combitube insertion had higher Face Abbreviated Injury Scale scores and were more likely to have oropharyngeal blood or vomitus. Arrival P co 2 values were higher, and arrival Po 2 values were lower but still supranormal in patients undergoing Combitube insertion. There were no mortality differences between patients undergoing Combitube insertion and those undergoing orotracheal intubation. Conclusion The Combitube can be an effective salvage airway device for paramedic rapid sequence intubation in an urban/suburban, high-volume emergency medical services system with paramedics who are experienced in Combitube placement and with stringent protocols for its use. The device should be tested in other sizes and types of systems and under less medical scrutiny than was used in this study.

The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.

To evaluate the effect of paramedic rapid sequence intubation (RSI) on outcome in patients with severe traumatic brain injury. Adult major trauma victims were prospectively enrolled over two years using the following inclusion criteria: Glasgow Coma Scale (GCS) 3-8, suspected head injury by mechanism or physical examination, transport time > 10," and inability to intubate without RSI. Midazolam and succinylcholine were administered before laryngoscopy; rocuronium was given after tube placement was confirmed using physical examination, capnometry, syringe aspiration, and pulse oximetry. The Combitube was used as a salvage airway device. For this analysis, trial patients were excluded for absence of a head injury (Head/Neck AIS score < 2), failure to fulfill major trauma outcome study criteria, unsuccessful intubation or Combitube insertion, or death in the field or in the resuscitation suite within 30" of arrival. Each study patient was hand matched to three nonintubated historical controls from our trauma registry using the following parameters: age, sex, mechanism of injury, trauma center, and AIS score for each body system. Controls were excluded for Head/Neck AIS defined by a c-spine injury or death in the field or in the resuscitation suite within 30" of arrival. chi 2, odds ratios, and logistic regression were used to investigate the impact of RSI on the primary outcome measures of mortality and incidence of a "good outcome," defined as discharge to home, rehabilitation, psychiatric facility, jail, or signing out against medical advice. A total of 209 trial patients were hand matched to 627 controls. The groups were similar with regard to all matching parameters, admission vital signs, frequency of specific head injury diagnoses, and incidence of invasive procedures. Mortality was significantly increased in the trial cohort versus controls for all patients (33.0% versus 24.2%, p < 0.05) and in those with Head/Neck AIS scores of 3 or greater (41.1% versus 30.3%, p < 0.05). The incidence of a "good outcome" was lower in the trial cohort versus controls (45.5% versus 57.9%, p < 0.01). Factors that may have contributed to the increase in mortality include transient hypoxia, inadvertent hyperventilation, and longer scene times associated with the RSI procedure. Paramedic RSI protocols to facilitate intubation of head-injured patients were associated with an increase in mortality and decrease in good outcomes versus matched historical controls.

S UCCESSFUL P REHOSPITAL A IRWAY M ANAGEMENT BY EMT-D S U SING THE C OMBITUBE

Objective. To evaluate the ability to train emergency medical technicians-defibrillation (EMT-Ds) to effectively use the Combitube for intubations in the prehospital environment. Methods. This was an 18-month prospective field study in which EMT-Ds were trained how and in what situations to use the Combitube. Data were then obtained for all patients in whom Combitube insertion was attempted. Indications for use of the Combitube included: unconsciousness without a purposeful response, absence of the gag reflex, apnea or respiratory rate less than 6 breaths/min, age more than 16 years, and height at least 5 feet tall. Contraindications were: obvious signs of death, intact gag reflex, inability to advance the device due to resistance, or known esophageal pathology. Data were entered prospectively from the San Diego County EMS QANet database for prehospital providers. Results. Twenty-two EMT-D provider agencies, involving approximately 500 EMT-Ds, were included as study participants. Combitube insertions were attempted in 195 prehospital patients in cardiorespiratory arrest, with appropriate indication for Combitube use. An overall successful intubation rate (defined as the ability to successfully ventilate) of 79% was observed. Identical success rates for medical and trauma patients were noted. The device was placed in the esophagus 91% of the time. Resistance during insertion was the major reason for unsuccessful Combitube intubations. An overall hospital admission rate of 19% was observed. No complications were reported. Conclusion. EMT-Ds can be trained to use the Combitube as a means of establishing an airway in the pre-hospital setting. Future studies will need to further evaluate its effect on patient outcome.

Ability of paramedics to use the Combitube in prehospital cardiac arrest.

To evaluate the ability of paramedics in a nonurban emergency medical services system to use the Combitube, a combined endotracheal and esophageal obturator airway adjunct, in prehospital cardiac arrest patients. A prospective, controlled study to evaluate the difficulty and complications of insertion, recognition of esophageal versus tracheal placement, skill proficiency, and retention. The ability to use the device in cases of failed endotracheal intubation also was scrutinized. Evaluation of the paramedic's ability to use the Combitube was performed in a prehospital environment. A follow-up study to determine retention of insertion skill was conducted in a controlled laboratory setting. Fifty-two cases of paramedic prehospital Combitube insertion were examined, and 11 paramedics were evaluated for skill retention. Combitube insertion was attempted on 52 prehospital patients in cardiac arrest, and 69% were intubated successfully. Paramedics recognized esophageal versus tracheal placement in 100% of the cases. The Combitube was inserted successfully into 64% of the patients who could not be endotracheally intubated by the conventional visualized method. The Combitube was inserted successfully 71% of the time when used as a first-line airway adjunct. A follow-up study on 11 randomly selected paramedics involved in the field study was conducted 15 months later. Nine of 11 paramedics demonstrated inadequate skill retention in the follow-up study. Although visualized endotracheal intubation remains the preferred method of airway control, the Combitube may be an effective prehospital airway device as both a backup to the endotracheal tube and a primary airway. Although the Combitube does not require visualization with a laryngoscope, comprehensive training and continuing education are key factors affecting skill retention.