Impact of Unexpected Death in a Simulation Scenario on Skill Retention, Stress, and Emotions: A Simulation-Based Randomized Controlled Trial.

Introduction The simulation of patient death remains controversial in simulation-based education. We investigated the effect of simulated patient death on learners' skill retention, stress levels, and emotions. Methods After ethics approval, we recruited residents at two Canadian universities. Participants were randomized to manage a simulated cardiac arrest ending with either the unexpected death (intervention group) or survival (control group) of the simulated patient (i.e., manikin). Three months later, all participants performed the same scenario but with the opposite outcome. Blinded video raters assessed participants' non-technical and technical crisis resource management (CRM) skills at both time points. Stress levels (represented by anxiety level, salivary cortisol concentration, and cognitive appraisal) and emotional valence were measured. Outcomes were analyzed using analysis of covariance (ANCOVA) or generalized estimating equations as appropriate. Results The analysis included 46 participants (intervention: n=24; control: n=22). Simulated death neither affected retention of non-technical CRM skills (mean retention Ottawa Global Rating Scale score in the death group [29.4, 95% CI: 27.0, 31.8] versus control group [29.4, 95% CI: 26.8, 32.0; p=0.87]) nor technical CRM skills (mean retention task-specific checklist score in the manikin death group [11.8, 95% CI: 10.5, 13.0] versus the control group [12.5, 95% CI: 11.3, 13.7; p=0.69]). The simulated death had negative effects on participants' anxiety levels, cognitive appraisal, and emotions. Conclusion Simulated patient death did not affect the retention of non-technical or technical CRM skills but led to greater levels of short-term anxiety, stress, and negative emotions among learners.

ST-T segment changes in prehospital emergency physicians in the field: a prospective observational trial.

AIMS: Due to time-critical decision-making, physical strain and the uncontrolled environment, prehospital emergency management is frequently associated with high levels of stress in medical personnel. Stress has been known to cause ischemia like changes in electrocardiograms (ECGs), including arrhythmias and deviations in ST-T segments. There is a lack of knowledge regarding the occurrence of changes in ST-T segments in prehospital emergency physicians. We hypothesized that ST-T segment deviations occur in prehospital emergency physicians in the field. METHODS: In this prospective observational trial, ST-T segments of emergency physicians were recorded using 12-lead Holter ECGs. The primary outcome parameter was defined as the incidence of ST-T segment changes greater than 0.1 mV in two corresponding leads for more than 30 s per 100 rescue missions. The secondary outcomes included T-wave inversions and ST-segment changes shorter than 30 s or smaller than 0.1 mV. Surrogate parameters of stress were measured using the NASA-Task Load Index and cognitive appraisal, and their correlation with ST-T segment changes were also assessed. RESULTS: Data from 20 physicians in 36 shifts (18 days, 18 nights) including 208 missions were analysed. Seventy percent of previously healthy emergency physicians had at least one ECG abnormality; the mean duration of these changes was 30 s. Significantly more missions with ECG changes were found during night than day shifts (39 vs. 17%, p < 0.001). Forty-nine ECG changes occurred between missions. No ST-T segment changes > 30 s and > 0.1 mV were found. Two ST-T segment changes < 30 s or < 0.1 mV (each during missions) and 122 episodes of T-wave inversions (74 during missions) were identified. ECG changes were found to be associated with alarms when asleep and NASA task load index. CONCLUSION: ECG changes are frequent and occur in most healthy prehospital emergency physicians. Even when occurring for less than 30 s, such changes are important signs for high levels of stress. The long-term impact of these changes needs further investigation. Trial registration The trial was registered at ClinicalTrials.gov (NCT04003883) on 1.7.2019:  https://clinicaltrials.gov/ct2/show/NCT04003883?term=emergency+physician&rank=2.

Digital Teaching in Medical Education: Scientific Literature Landscape Review.

BACKGROUND: Digital teaching in medical education has grown in popularity in the recent years. However, to the best of our knowledge, no bibliometric report to date has been published that analyzes this important literature set to reveal prevailing topics and trends and their impacts reflected in citation counts. OBJECTIVE: We used a bibliometric approach to unveil and evaluate the scientific literature on digital teaching research in medical education, demonstrating recurring research topics, productive authors, research organizations, countries, and journals. We further aimed to discuss some of the topics and findings reported by specific highly cited works. METHODS: The Web of Science electronic database was searched to identify relevant papers on digital teaching research in medical education. Basic bibliographic data were obtained by the "Analyze" and "Create Citation Report" functions of the database. Complete bibliographic data were exported to VOSviewer for further analyses. Visualization maps were generated to display the recurring author keywords and terms mentioned in the titles and abstracts of the publications. RESULTS: The analysis was based on data from 3978 papers that were identified. The literature received worldwide contributions with the most productive countries being the United States and United Kingdom. Reviews were significantly more cited, but the citations between open access vs non-open access papers did not significantly differ. Some themes were cited more often, reflected by terms such as virtual reality, innovation, trial, effectiveness, and anatomy. Different aspects in medical education were experimented for digital teaching, such as gross anatomy education, histology, complementary medicine, medicinal chemistry, and basic life support. Some studies have shown that digital teaching could increase learning satisfaction, knowledge gain, and even cost-effectiveness. More studies were conducted on trainees than on undergraduate students. CONCLUSIONS: Digital teaching in medical education is expected to flourish in the future, especially during this era of COVID-19 pandemic.

Impact of Infant Positioning on Cardiopulmonary Resuscitation Performance During Simulated Pediatric Cardiac Arrest: A Randomized Crossover Study.

OBJECTIVES: The primary objective was to determine the impact of infant positioning on cardiopulmonary resuscitation performance during simulated pediatric cardiac arrest. DESIGN: A single-center, prospective, randomized, unblinded manikin study. SETTING: Medical university-affiliated simulation facility. SUBJECTS: Fifty-two first-line professional rescuers (n = 52). INTERVENTIONS: Performance of cardiopulmonary resuscitation was determined using an infant manikin model in three different positions (on a table [T], on the provider's forearm with the manikin's head close to the provider's elbow [P], and on the provider's forearm with the manikin's head close to the provider's palm [D]). For the measurement of important cardiopulmonary resuscitation performance variables, a commercially available infant simulator was modified. In a randomized sequence, healthcare professionals performed single-rescuer cardiopulmonary resuscitation for 3 minutes in each position. Performances of chest compression (primary outcome), ventilation, and hands-off time were analyzed using a multilevel regression model. MEASUREMENTS AND MAIN RESULTS: Mean (± SD) compression depth significantly differed between table and the other two manikin positions (31 ± 2 [T], 29 ± 3 [P], and 29 ± 3 mm [D]; overall p < 0.001; repeated measures design adjusted difference: T vs P, -2 mm [95% CI, -2 to -1 mm]; T vs D, -1 mm [95% CI, -2 to -1 mm]). Secondary outcome variables showed no significant differences. CONCLUSIONS: Compressions were significantly deeper in the table group compared to positions on the forearm during cardiopulmonary resuscitation, yet the differences were small and perhaps not clinically important.

Providing the best chest compression quality: Standard CPR versus chest compressions only in a bystander resuscitation model.

AIM OF THE STUDY: Bystander-initiated basic life support (BLS) for the treatment of prehospital cardiac arrest increases survival but is frequently not performed due to fear and a lack of knowledge. A simple flowchart can improve motivation and the quality of performance. Furthermore, guidelines do recommend a chest compression (CC)-only algorithm for dispatcher-assisted bystander resuscitation, which may lead to increased fatigue and a loss of compression depth. Consequently, we wanted to test the hypothesis that CCs are more correctly delivered in a flowchart-assisted standard resuscitation algorithm than in a CC-only algorithm. METHODS: With the use of a manikin model, 84 laypersons were randomized to perform either flowchart-assisted standard resuscitation or CC-only resuscitation for 5min. The primary outcome was the total number of CCs. RESULTS: The total number of correct CCs did not significantly differ between the CC-only group and the standard group (63 [±81] vs. 79 [±86]; p = 0.394; 95% CI of difference: 21-53). The total hand-off time was significantly lower in the CC-only group than in the standard BLS group. The relative number of correct CCs (the fraction of the total number of CCs achieving 5-6cm) and the level of exhaustion after BLS did not significantly differ between the groups. CONCLUSION: Standard BLS did not lead to an increase in correctly delivered CCs compared to CC-only resuscitation and exhibited significantly more hand-off time. The low rate of CCs in both groups indicates the need for an increased focus on performance during BLS training.

Biotechnology and the bioeconomy-Towards inclusive and sustainable industrial development.

To transform developing and least developing countries into industrialised ones, biotechnology could be deployed along the value chain, to provide support to the development of the bio-based industries in such a way to ensure sustainability of the sector and to reduce negative environmental impacts that might otherwise occur. In agribusiness development, for instance, interventions could start from inputs and agricultural mechanization, modern processing technologies, packaging of perishable products, the promotion of food safety in the processing and regulatory environment; and interventions to improve competitiveness and productivity. Worth over USD 300 billion in revenue, the role of the biotechnology goes beyond industrial growth, since it provides opportunities for progress towards many of the UN sustainable development goals (SDGs). This paper reviews the status of industrial biotechnology as it relates to inclusive and sustainable industrial development.

Retention of Basic Life Support in Laypeople: Mastery Learning vs. Time-based Education.

OBJECTIVE: To compare the effectiveness of a mastery learning (ML) versus a time-based (TB) BLS course for the acquisition and retention of BLS knowledge and skills in laypeople. METHODS: After ethics approval, laypeople were randomized to a ML or TB BLS course based on the American Heart Association (AHA) Heartsaver course. In the ML group, subjects practiced and received feedback at six BLS stations until they reached a pre-determined level of performance. The TB group received a standard AHA six-station BLS course. All participants took the standard in-course BLS skills test at the end of their course. BLS skills and knowledge were tested using a high-fidelity scenario and knowledge questionnaire upon course completion (immediate post-test) and after four months (retention test). Video recorded scenarios were assessed by two blinded, independent raters using the AHA skills checklist. RESULTS: Forty-three subjects were included in analysis (23ML;20TB). For primary outcome, subjects' performance did not change after four months, regardless of the teaching modality (TB from (median[IQR]) 8.0[6.125;8.375] to 8.5[5.625;9.0] vs. ML from 8.0[7.0;9.0] to 7.0[6.0;8.0], p = 0.12 for test phase, p = 0.21 for interaction between effect of teaching modality and test phase). For secondary outcomes, subjects acquired knowledge between pre- and immediate post-tests (p < 0.005), and partially retained the acquired knowledge up to four months (p < 0.005) despite a decrease between immediate post-test and retention test (p = 0.009), irrespectively of the group (p = 0.59) (TB from 63.3[48.3;73.3] to 93.3[81.7;100.0] and then 93.3[81.7;93.3] vs. ML from 60.0[46.7;66.7] to 93.3[80.0;100.0] and then 80.0[73.3;93.3]). Regardless of the group after 4 months, chest compression depth improved (TB from 39.0[35.0;46.0] to 48.5[40.25;58.0] vs. ML from 40.0[37.0;47.0] to 45.0[37.0;52.0]; p = 0.012), but not the rate (TB from 118.0[114.0;125.0] to 120.5[113.0;129.5] vs. ML from 119.0[113.0;130.0] to 123.0[102.0;132.0]; p = 0.70). All subjects passed the in-course BLS skills test. Pass/fail rates were poor in both groups at both the simulated immediate post-test (ML = 1/22;TB = 0/20; p = 0.35) and retention test (ML pass/fail = 1/22, TB pass/fail = 0/20; p = 0.35). The ML course was slightly longer than the TB course (108[94;117] min vs. 95[89;102] min; p = 0.003). CONCLUSIONS: There was no major benefit of a ML compared to a TB BLS course for the acquisition and four-month retention of knowledge or skills among laypeople.

The Impact of Monitoring on the Initiation of Cardiopulmonary Resuscitation in Children: Friend or Foe?

BACKGROUND: The immediate initiation and high quality of basic life support (BLS) are pivotal to improving patient outcome after cardiac arrest. Although cardiorespiratory monitoring could shorten the time to recognize the onset of cardiac arrest, little is known about how monitoring and the misinterpretation of monitor readings could impair the initiation of BLS. In this study, we assessed the speed of initiation and quality of BLS in simulated monitored and nonmonitored pediatric cardiac arrest. METHODS: Sixty residents frequently involved in the care of critically ill children were randomly assigned to either the intervention (monitoring) group or the control (nonmonitoring) group. Participants of both groups performed BLS in 1 of 2 clinically identical, unwitnessed simulated cardiac arrest scenarios. Although in 1 scenario cardiorespiratory monitoring (i.e., electrocardiogram) was attached, the other scenario reflected a nonmonitored cardiac arrest. Time to first chest compression was chosen as the primary outcome variable. Adherence to resuscitation guidelines and subjective performance ratings were secondary outcome variables. RESULTS: Participants in the monitoring group initiated chest compressions significantly later than those in the nonmonitoring group (91 ± 36 vs 71 ± 26 seconds, hazard ratio, 0.26; 95% confidence interval, 0.14-0.49, P < 0.001). Six members of the monitoring group did not start chest compression within 5 minutes. Furthermore, adherence to the guidelines was better in the nonmonitoring group. Participants who were previously involved in BLS training did not show better performance. CONCLUSIONS: The presence of cardiorespiratory monitoring significantly delayed or even prevented the initiation of chest compressions and impaired the quality of BLS in simulated pediatric cardiac arrest. Based on these data, specific training should be conducted for exposed personnel.

Distance from the glottis to the grille: the LMA Unique, Air-Q and CobraPLA as intubation conduits: a randomised trial.

BACKGROUND: Supraglottic airway devices are often used in airway management to facilitate tracheal intubation. Knowledge of the distance from the grille of the device to the patient's vocal cords is essential for the safe passage of the tracheal tube below the vocal cords. OBJECTIVES: To assess the distance from the glottis to the grille of three supraglottic airway devices [LMA (LMA Unique), Air-Q (Air-Q Intubating Laryngeal Airway Reusable) and CobraPLA (Cobra Perilaryngeal Airway)] and their safe usage as intubation conduits. DESIGN: Randomised controlled trial. SETTING: Tertiary, university hospital. PATIENTS: Thirty women undergoing elective gynaecological surgery with planned supraglottic airway management. INTERVENTIONS: In-vivo fibreoptic assessment and in-vitro measurement. MAIN OUTCOME MEASURES: The distance from the grille to the glottis was defined as primary outcome. The distance from the beginning of the cuff of a tracheal tube passed through the device to the grille was assessed as secondary outcome. RESULTS: The three devices exhibited significant differences in the mean ±â€ŠSD distance from the glottis to the grille (LMA 4.6 ±â€Š1.5  cm, Air-Q 5.7 ±â€Š1.4  cm, CobraPLA 3.4 ±â€Š1.4  cm; P = 0.009). The Air-Q was predicted to allow the safe passage of a tracheal tube into the trachea, whereas the cuff was predicted to rest on the vocal cords in 57% of the LMA patients and 14% of the CobraPLA patients. CONCLUSION: Using the LMA Unique as a conduit for tracheal intubation may pose a safety risk, whereas the use of the Air-Q would position the tracheal tube at a safe depth in the trachea.

Preparedness of anesthesiologists working in humanitarian disasters.

OBJECTIVE: Many skills needed to provide patients with safe, timely, and adequate anesthesia care during humanitarian crisis and disaster relief operations are not part of the daily routine before deployment. An exploratory study was conducted to identify preparedness, knowledge, and skills needed for deployment to complex emergencies. METHODS: Anesthesiologists who had been deployed during humanitarian crisis and disaster relief operations completed an online questionnaire assessing their preparedness, skills, and knowledge needed during deployment. Qualitative data were sorted by frequencies and similarities and clustered accordingly. RESULTS: Of 121 invitations sent out, 55 (46%) were completed and returned. Of these respondents, 24% did not feel sufficiently prepared for the deployment, and 69% did not undertake additional education for their missions. Insufficient preparedness involved equipment, drugs, regional anesthesia, and related management. CONCLUSIONS: As the lack of preparation and relevant training can create precarious situations, anesthesiologists and deploying agencies should improve preparedness for anesthesia personnel. (Disaster Med Public Health Preparedness. 2013;0;1-5).

Crystalloids versus colloids during acute normovolemic anemia: the quest continues...

The optimal kind of fluid for fluid resuscitation during acute, severe hemorrhage is still discussed controversially. Of particular interest in this context is the choice of colloids versus crystalloids and their effect on the critical hemoglobin level. In a previous issue of Critical Care, Pape and colleagues describe the effect of four different volume replacement options on the critical hemoglobin concentration, and show marked differences for the different treatments. Even though some important pathophysiological issues remain unsolved, the current manuscript adds interesting evidence to an ongoing quest.

Degrees of reality: airway anatomy of high-fidelity human patient simulators and airway trainers.

BACKGROUND: Human patient simulators and airway training manikins are widely used to train airway management skills to medical professionals. Furthermore, these patient simulators are employed as standardized "patients" to evaluate airway devices. However, little is known about how realistic these patient simulators and airway-training manikins really are. This trial aimed to evaluate the upper airway anatomy of four high-fidelity patient simulators and two airway trainers in comparison with actual patients by means of radiographic measurements. The volume of the pharyngeal airspace was the primary outcome parameter. METHODS: Computed tomography scans of 20 adult trauma patients without head or neck injuries were compared with computed tomography scans of four high-fidelity patient simulators and two airway trainers. By using 14 predefined distances, two cross-sectional areas and three volume parameters of the upper airway, the manikins' similarity to a human patient was assessed. RESULTS: The pharyngeal airspace of all manikins differed significantly from the patients' pharyngeal airspace. The HPS Human Patient Simulator (METI®, Sarasota, FL) was the most realistic high-fidelity patient simulator (6/19 [32%] of all parameters were within the 95% CI of human airway measurements). CONCLUSION: The airway anatomy of four high-fidelity patient simulators and two airway trainers does not reflect the upper airway anatomy of actual patients. This finding may impact airway training and confound comparative airway device studies.

Medical information on the Internet: Quality assessment of lumbar puncture and neuroaxial block techniques on YouTube.

BACKGROUND: The Internet has become the largest, most up-to-date source for medical information. Besides enhancing patients' knowledge, the freely accessible audio-visual files have an impact on medical education. However little is known about their characteristics. In this manuscript the quality of lumbar puncture (LP) and spinal anaesthesia (SA) videos available on YouTube is assessed. METHODS: This retrospective analysis was based on a search for LP and SA on YouTube. Videos were evaluated using essential key points (5 in SA, 4 in LP) and 3 safety indicators. Furthermore, violation of sterile working techniques and a rating whether the video must be regarded as dangerously misleading was performed. RESULTS: From 2321 hits matching the keywords, 38 videos were eligible for evaluation. In LP videos, 14% contained information on all, 4.5% on 3 and 4.5% on 2 key points, 59% on 1 and 18% on no key point. Regarding SA, no video contained information on all 5 key points, 56% on 2-4 and 25% on 1 key point, 19% did not contain any essential information. A sterility violation occurred in 11%, and 13% were classified as dangerously misleading. CONCLUSIONS: Even though high quality videos are available, the quality of video clips is generally low. The fraction of videos that were not performed in an aseptic manner is low, but these pose a substantial risk to patients. Consequently, more high-quality, institutional medical learning videos must be made available in the light of the increased utilization on the Internet.

A comparison of paediatric airway anatomy with the SimBaby high-fidelity patient simulator.

BACKGROUND: The SimBaby high-fidelity patient simulator is a widely used paediatric simulator for the training of standard and critical airway management scenarios. Furthermore this simulator is frequently used for the evaluation of different airway devices and techniques. However, the anatomic structures of the SimBaby have not been compared to actual patients' anatomy. METHODS: The CT radiographic measures of the upper airway anatomy of two SimBaby simulators were compared to MRI images of the upper airway of 20 children aged 1-11 months who underwent routine MRI scans under sedation for diagnostic purposes. Various distances of the tongue, soft palate and pharynx, cross sectional areas and volumes of anatomic structures of the upper airway including the retroglossal airspace were compared. RESULTS: The SimBaby's retroglossal airspace volume greatly differed from the measurements in patients (SimBaby 5.3±0.4 vs. 1.9±0.8 cm(3) in infants, p<0.01). Furthermore the distance from the alveolar process of the mandible to the posterior pharyngeal wall was larger in the SimBaby than in infants (5.8±0.1 vs. 4.5±0.5 cm, p<0.001) and dimensions of the epiglottis and pharynx were larger in the Simbaby. CONCLUSION: The anatomic features of the SimBaby do not adequately simulate the upper airway anatomy of infants. These results imply inadequate realism of this simulator for airway training and compromise the validity of comparative trials of different airway devices with the SimBaby as airway model.

Topical lidocaine reduces the risk of perioperative airway complications in children with upper respiratory tract infections.

PURPOSE: To determine the effect of topically applied lidocaine on perioperative airway complications when using a laryngeal mask airway device (LMAD) in children either with or without a history of recent or ongoing upper respiratory tract infection (URI). METHODS: In a randomized controlled double-blind trial, 34 children with a history of recent or ongoing URI and 32 non-URI children- all of whom were younger than age ten and scheduled to undergo minor surgical procedures-were randomly assigned to either a lidocaine or a placebo group. In the lidocaine group, an LMAD was lubricated with lidocaine gel before insertion, and a clear lubricating gel was used in the placebo group. The following data were recorded after standardized anesthesia induction and airway management: postoperative complications, such as coughing, desaturation, laryngospasm, and increased oral secretions, as well as length of stay in the postanesthetic recovery unit. RESULTS: Children with URI had a lower overall perioperative complication rate if they received a lidocaine gel (35%) rather than placebo (94%) (P < 0.01). Also, the incidence of postoperative coughing was less (12% vs 53%; P = 0.03). In non-URI patients, lidocaine did not significantly reduce the rate of airway complications compared with placebo (17% vs 24%, respectively). CONCLUSION: Lubrication of the LMAD with lidocaine gel reduces the incidence of airway complications in children with an upper respiratory tract infection.

Comparison of the EasyTube and endotracheal tube during general anesthesia in fasted adult patients.

STUDY OBJECTIVE: To evaluate the effectiveness, safety, ease of placement, and ventilatory parameters of a new alternate airway device, the EasyTube (EzT; Teleflex Ruesch, Research Triangle Park, NC), in comparison to the endotracheal tube (ETT). DESIGN: Prospective, randomized controlled trial. SETTING: University Hospital. SUBJECTS: 200 adult ASA physical status I and II patients scheduled for surgery. INTERVENTIONS: Patients were randomized to two groups, one to receive ventilation via the EzT (n = 100) or the ETT (n = 100). After preoxygenation and induction with fentanyl and propofol, patients received muscle relaxation. The respective airway device was then inserted and mechanical ventilation was instituted. MEASUREMENTS: Ease of insertion, number of insertion maneuvers, time until airtight seal of the airway was achieved, duration of surgery, leak pressure as well as arterial oxygen saturation (SpO(2)), and end-tidal carbon dioxide (ETCO(2)) data, were recorded. MAIN RESULTS: Mallampati airway class was higher in the EzT group (P < 0.029), while thyromental distance showed no difference between the two groups. Ease of insertion was noted in the EzT group (P < 0.043). Number of insertions was equal in both groups; insertion time was shorter with the EzT (15.5 +/- 3.6 sec vs. 19.3 +/- 4.6 sec; P < 0.0001). Leak pressure and SpO(2) were not significantly different, while ETCO(2) was lower with the ETT (P < 0.024). Adjustments had to be made for two EzT group patients. No difference in frequency of laryngo-pharyngeal discomfort was observed in either group. CONCLUSION: Insertion of an EzT appears to reduce time and facilitate placement of an airway device when compared with direct laryngoscopy and tracheal intubation.

Tissue oxygenation in obese and non-obese patients during laparoscopy.

BACKGROUND: Wound infection risk is inversely related to subcutaneous tissue oxygenation, which is reduced in obese patients and may be reduced even more during laparoscopic procedures. METHODS: We evaluated subcutaneous tissue oxygenation (PsqO(2)) in 20 patients with a body mass index (BMI) > or=40 kg/m(2) (obese group) and 15 patients with BMI <30 kg/m(2) (non-obese group) undergoing laparoscopic surgery with standardized anaesthesia technique and fluid administration. Arterial oxygen tension was maintained near 150 mmHg. PsqO(2) was measured from a surrogate wound on the upper arm. RESULTS: A mean FIO(2) of 51% (13%) was required in obese patients to reach an arterial oxygen tension of 150 mmHg; however, a mean FIO(2) of only 40% (7%) was required to reach the same oxygen tension in non-obese patients (P=0.007). PsqO(2) was significantly less in obese patients: 41 (10) vs 57 (15) mmHg (P<0.001). CONCLUSION: Obese patients having laparoscopic surgery require a significantly greater FIO(2) to reach an arterial oxygen tension of about 150 mmHg than non-obese patients; they also have significantly lower subcutaneous oxygen tensions. Both factors probably contribute to an increased infection risk in obese patients.

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

PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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.