Experiential learning improves the learning and retention of endotracheal intubation

Context  Simulators provide an effective platform for the learning of clinical motor skills such as endotracheal intubation, although the optimal learning technique remains unidentified. We hypothesised that, for novices, experiential learning would improve the learning and retention of endotracheal intubation compared with guided learning.
Methods  Year 4 medical students were randomised to either guided or experiential learning. Students in the guided group were taught using the conventional step-by-step technique. Students in the experiential group had to work out the correct technique for intubation on their own. Both groups had further opportunities to intubate manikins and patients during their postings. The students were recalled 3, 6, 9 and 12 months later, and their intubation skills assessed in four major categories: equipment preparation; intubation technique; successful intubation, and placement confirmation.
Results  A total of 210 students (107 guided, 103 experiential) participated in the study. At 3 months, 64.5% of the students in the experiential group successfully intubated the manikin, compared with 36.9% in the guided group ( P  < 0.001). The experiential group also had higher overall scores, signifying quality of intubation attempts, at 3 months (79% versus 70%; P  < 0.001). Success rates and overall scores for both groups were comparable at 6 and 9 months, but were better in the experiential group at 12 months. Success rates improved with time, reaching 86% at 12 months.
Conclusions  Novices learned and retained the skill of endotracheal intubation better with experiential learning. This study suggests that experiential learning should be adopted for the teaching of endotracheal intubation and that refresher tuition at 3-monthly intervals will prevent the decay of this skill in infrequent users.     

How Can I Know What I Don't Know? Poor Self Assessment in a Well-Defined Domain

As the rapidity with which medical knowledge is generated and disseminated becomes amplified, an increasing emphasis has been placed on the need for physicians to develop the skills necessary for life-long learning. One such skill is the ability to evaluate one's own deficiencies. A ubiquitous finding in the study of self-assessment, however, is that self-ratings are poorly correlated with other performance measures. Still, many educators view the ability to recognize and communicate one's deficiencies as an important component of adult learning. As a result, two studies have been performed in an attempt to improve upon this status quo. First, we tried to re-define the limits within which self-assessments should be used, using Rosenblit and Keil's argument that calibration between perceived and actual performance will be better within taxonomies that are regularly tested (e.g., factual knowledge) compared to those that are not (e.g., conceptual knowledge). Second, we tried to norm reference individuals based on both the performance of their colleagues and their own historical performance on McMaster's Personal Progress Inventory (a multiple choice question test of medical knowledge). While it appears that students are able to (a) make macro-level self-assessments (i.e., to recognize that third year students typically outperform first year students), and (b) judge their performance relatively accurately after the fact, students were unable to predict the percentage of questions they would answer correctly with a testing procedure in which they have had a substantial amount of feedback. Previous test score was a much better predictor of current test performance than were individuals' expectations.     

Pneumothorax following attempted nasogastric intubation for nutritional support

Nasogastric intubation is a routine procedure, performed daily by both medical and nursing staff. It is a simple procedure, but not without complications which can be life threatening. We present an unusual, life threatening complication which occurred when nasogastric intubation using a no. 8 polyurethane tube with its metal stilet resulted in a pneumothorax after intubation of the endotracheal tree in the presence of a cuffed endotracheal tube. We emphasize that the presence of a cuffed endotracheal tube should not be considered a safeguard against pulmonary intubation during nasogastric placement of a feeding catheter.     

喉罩与气管导管在全麻中的应用对比

目的比较喉罩与气管导管置入行全麻对患者血流动力学,首次置入成功率,术后恶心、呕吐和咽部刺激症状等方面的影响。方法择期全麻手术患者60例,随机分为A组和B组,全麻诱导后A组采用气管导管置入,而B组使用喉罩,每组各30例;分别记录喉罩与气管导管置入过程中患者心率、血压的变化,首次置入成功率以及术后患者有无发生恶心、呕吐和咽部刺激症状。结果喉罩组在心率及血压变化、首次置入成功率、术后恶心、呕吐和咽部刺激症状等方面均优于导管组。结论全麻诱导后喉罩置入血流动力学稳定,首次置入成功率高,对咽部刺激小,该方法简便、安全、有效和副作用少,值得临床推广应用。     

Improving learning of a clinical skill: the first year's experience of teaching endotracheal intubation in a clinical simulation facility

BACKGROUND: All medical practitioners should be able to manage the airway of an unconscious patient. Endotracheal intubation is the most effective method of securing the airway but is a complex skill requiring much practice. Traditionally, endotracheal intubation has been taught on patients, but this is not ideal. METHODS: We have developed a short course on endotracheal intubation taught in a clinical simulation unit (CSU). This unit has a large range of airway trainers and patient simulators, some of which can be manipulated to make intubation more difficult. Endotracheal intubation is taught in a series of steps in order to avoid cognitive overload. Each step is taught on an airway trainer that has no difficult features. Once this is mastered, more difficult situations are presented which require application of new techniques and/or equipment. In this way, students learn useful schemas to apply clinically. RESULTS: In 1 year, over 100 students and trainees were taught endotracheal intubation in the CSU. The ideal group size was found to be two students and one trainer. It took 75 to 90 minutes for most students to reach a standard where they could be expected to safely perform the technique on a patient. All comments on learning endotracheal intubation in this setting were positive. Many students felt more comfortable learning on a model than on a patient. CONCLUSION: Learning clinical procedures on simulators is becoming an essential part of medical education. More than one airway trainer may be needed to give students the expertise to perform endotracheal intubation on patients.     

Methods and complications of nasoenteral intubation

Nasoenteral intubation is among the most common procedures performed by clinicians across all medical specialties. The most common technique for nasoenteral intubation is blind passage, as it does not require the use of sophisticated or expensive medical equipment. Unfortunately, blind placement too frequently results in trauma and is a source of significant morbidity and mortality. It is apparent that altered mental status, a preexisting endotracheal tube, and critical illness put a patient in a higher risk group for malposition and complications. Nasoenteral intubation should be attempted only with an understanding of the possibility for difficult placement and the potential complications that can arise from trauma or malposition.     

使用可视插管软镜气管插管160例临床评价

目的评价一种新型的可视插管软镜在普通患者气管插管中的使用效果和安全性。方法选择4个月内预计非困难气道的全身麻醉气管插管择期手术患者160名,ASAⅠ^Ⅱ级,Mallampati气道分级ⅠⅡ级,Mallampati气道分级Ⅰ^Ⅳ级,随机分为4组。麻醉诱导后,4组患者分别由4名麻醉医生使用可视插管软镜行经口气管插管。记录声门暴露时间、插管时间(入镜开始到退镜结束)和插管次数。观察患者插管期间氧饱和度的变化和其他并发症。术后随访患者是否出现插管相关并发症。结果 160名患者均顺利完成气管插管,124名患者一次成功(77.5%),声门暴露时间为(15±9)s,插管时间为(21±12)s,术后随访无并发症。结论可视插管软镜用于普通患者的气管插管使用方便,插管成功率高,损伤小。     

Determination of a practical pH cutoff level for reliable confirmation of nasogastric tube placement

Background: Enteral feeding is a common method of nutrition support when oral intake is inadequate. Confirmation of correct nasogastric (NG) tube placement is essential. Risks of morbidity/mortality associated with misplacement in the lung are well documented. Studies indicate that pH ≤4 confirms gastric aspirate, but in pediatrics, a pH of gastric aspirate is often >4. The goal of this study was to determine a reliable and practical pH value to confirm NG tube placement, without increasing the risk of not identifying a misplaced NG tube. Methods: Pediatric inpatients older than 4 weeks receiving enteral nutrition (nasogastric or gastrostomy) were recruited over 9 months. Aspirate samples were pH tested at NG tube placement and before feedings. If pH >4, NG tube position was confirmed by chest radiograph or further investigations. In addition, intensive care unit (ICU) patients who required endotracheal suctioning were recruited, and endotracheal aspirate samples were pH tested. Results: A total of 4,330 gastric aspirate samples (96% nasogastric) were collected from 645 patients with a median (interquartile range [IQR]) age of 1.0 years (0.3–5.2 years). The mean (standard deviation [SD]) pH of these gastric samples was 3.6 (1.4) (range, 0–9). pH was >4 in 1,339 (30.9%) gastric aspirate samples, and of these, 244 were radiographed, which identified 10 misplaced tubes (1 with pH 5.5). A total of 65 endotracheal aspirate samples were collected from 19 ICU patients with a median (IQR) age of 0.6 years (0.4–5.2 years). The mean (SD) pH of these samples was 8.4 (0.8) (range, 6–9.5). Conclusion: Given that the lowest pH value of endotracheal aspirate sample was 6, and a misplaced NG tube was identified with pH 5.5, it is proposed that a gastric aspirate pH ≤5 is a safer, reliable, and practical cutoff in this population.     

Clinical evaluation of a newly designed nasogastric enteral feeding tube

Concerned with reports in the literature of a rising incidence of enteral feeding tube clogging, we initiated a design programme in an attempt to improve the clinical efficacy of nasogastric and nasoenteric enteral feeding tubes. Tube design has been based on a remodelling of the outflow part of a polyurethane feeding tube previously developed in our unit. The tip of the newly designed 8F enteral feeding tube is shorter in length with a rounded end to minimize discomfort during intubation. The port itself incorporates a tapered outflow design with the side walls now extending below the mid-point of the internal flow lumen resulting in a 28% increase in port area compared to the equivalent and originally designed tube. The performance of the newly designed polyurethane feeding tube was assessed under controlled trial conditions using as references two widely used 8F polyurethane nasogastric feeding tubes whose design has been based on different principles (Flexiflo, weighted tip, open-ended with two side ports; Freka, occluded tip, two simple large side ports). Eighty-eight of 90 patients entered into the study were successfully intubated with no significant differences being noted in intubation times in the three groups. Significantly less discomfort occurred during intubation of patients with the Radius tube as compared to the Freka tube (P < 0.05). Although there were no clear differences between the Flexiflo and Freka tubes either in regard to the number of attempts required for intubation or aspiration or discomfort during intubation or ease of aspiration, fewer attempts at insertion and aspiration were needed and intubation and aspiration were easier for patients randomised to the Radius group than those to the Flexiflo and Freka groups (P < 0.05). We conclude that the clinical performance of the newly designed Radius enteral feeding tube compares favourably with that of the reference tubes. Only one of the new tubes (3.3%) blocked during the course of the study. High rates of non-elective extubation were observed in the three study groups (Radius 80.0%, Flexiflo 73.3%, Freka 73.3%). Design modifications are unlikely to influence non-elective nasogastric feeding tube extubation rates which remain a major clinical problem.     

超滑涂层气管导管用于全麻下非困难气道气管插管的临床效果

目的:与普通气管导管相比,观察超滑涂层气管导管是否减轻全麻插管刺激及改善操作效果。方法:选取2016年7月~2017年1月全麻插管的患者60例,ASA分级Ⅰ~Ⅱ级,患者随机分为超滑气管导管组(观察组)和普通气管导管组(对照组)。记录插管时间和插管阻力评价;记录诱导前(T0)、插管前(T1)、插管即刻(T2)、插管后1min(T3)、3min(T4)、5min(T5)、术毕自主呼吸恢复(T6)SBP、DBP、MAP和HR;记录拔管后和术后24h出现咽痛的情况。结果:两组患者T2、T3、T6时对照组SBP、DBP和MAP明显高于观察组(P<0.01),T2、T3、T4时对照组HR明显高于观察组(P<0.01),观察组插管时间短于对照组(P<0.05),对照组术后咽痛发生高于观察组(P<0.05)。结论:超滑气管导管在非困难气道使用时有益于患者血流动力学平稳,缩短插管时间,有效降低术后咽痛的发生率,是一种安全有效的气管插管工具。     

Nasopulmonary intubation with feeding tubes: case reports and review of the literature

Pulmonary aspiration of regurgitated feeding material is a recognized complication of enteral nutrition by feeding tube. Nasopulmonary intubation with feeding tubes has been reported infrequently. We present two patients with such complications. In one, nasopulmonary intubation resulted in a pneumothorax. In the other unrecognized misplacement resulted in pneumonia and hydrothorax. Similar cases in the literature are discussed. Common features of this complication are: (1) patients who are obtunded, debilitated, or without gag reflex; (2) previous successful insertion of a tube; (3) successful passage past endotracheal tubes and tracheostomies; and (4) positive auscultation of insufflated air over the left upper quadrant. Complete prevention of this complication probably is not possible, but health care personnel should be aware of this potential problem in the patient at risk.     

Pulmonary complications of 9931 narrow-bore nasoenteric tubes during blind placement: a critical review

Introduction: A critical review of the pulmonary complications associated with blind placement of narrow‐bore nasoenteric tubes (NETs) is discussed. Preventive measures and placement techniques are addressed to decrease patient morbidity and mortality. Methods: A thorough database review was conducted to identify all randomized controlled and retrospective trials specifically addressing pulmonary complications from narrow‐bore NET placement. Five unique studies, comprising more than 9900 NET placements, were identified. On the basis of the literature reviewed, the authors identified 3 major complications associated with blind NET placement: patient mortality directly resulting from NET misplacement, incidence of tracheopulmonary malpositioning, and correlation between NET misplacement and mechanical ventilation. Results: Of the 9931 NET placements reviewed, there were 187 total improper tube placements in the tracheobronchial tree, which translates to a 1.9% mean overall malposition rate. Of these 187 misplacements, there were 35 (18.7%) reported pneumothoraces, at least 5 of which resulted in patient death. NET malpositioning was reported in 13%–32% of subsequent repositioning attempts. This increased risk exposes the patient population to a cumulative mortality from tracheobronchial malpositioning approaching >20%. Unexpectedly, of the 187 total misplacements, 113 (60.4%) of the patients were mechanically ventilated. Conclusions: Practitioners need to be aware of the potential for pulmonary complications associated with blind NET placement. Changes in institutional protocol should be considered to minimize unnecessary risks. As with any procedure, experienced personnel should be primarily used for tube placement and responsible for assisting others with less familiarity to learn the proper methods.     

急诊重症医学科气管插管相关不良事件应急处理分析

目的分析急诊重症医学科气管插管相关不良事件，提高医护人员预防与应急处理能力。 方法回顾性分析2015年1月至2018年12月南通市第一人民医院急诊重症医学科3个部门(急诊ICU、急诊内科监护室、综合ICU)气管插管患者发生不良事件及发生后的应急处理。共纳入392例经口气管插管患者，其中男性204例，女性188例；年龄16～93岁，平均(54.62±6.28)岁。采取调整导管位置、彻底清除气道分泌物、简易呼吸器加压给氧、重新气管插管或经皮扩张气管切开等处理方法，比较不良事件发生前后生命体征的变化。鼓励非惩罚性上报不良事件，分析不良事件种类、时间分布、年度分布、科室分布、原因分布。 结果392例经口气管插管患者发生不良事件53例，发生率为13.5%。其中综合ICU 1例患者气管导管置换时发生插管困难，考虑喉头水肿，家属放弃气管切开等进一步治疗；另1例重度肥胖患者困难气道，请麻醉师协助经口气管插管后气囊漏气，家属拒绝再次插管或气管切开，放弃治疗。其余51例经现场迅速处理，生命体征指标恢复到不良事件发生前的状态，未发生严重后果。 结论急诊重症医学科经口气管插管不良事件发生率较高，积极预防和现场快速判断、正确处理，可以减轻患者痛苦，防止严重后果发生。     

Influences on medical students' self-regulated learning after test completion

Medical Education 2012: 46 : 326–335 Context The inadequacy of self‐assessment as a mechanism to guide performance improvements has placed greater emphasis on the value of testing as a pedagogic strategy. The mechanism whereby testing influences learning is incompletely understood. This study was performed to examine which aspects of a testing experience most influence self‐regulated learning behaviour among medical students. Methods Sixty‐seven medical students participated in a computer‐based, multiple‐choice test. Initially, participants were instructed to attempt only items for which they felt confident of their response. They were then asked to indicate their best responses to deferred items. Students were then given an opportunity to review the items, with correct responses indicated. Accuracy, the attempt/defer decision and the time taken to reach this decision were recorded, along with participants’ ratings of their confidence in each response and the time spent reviewing each item on completion of the test. Results Students correctly answered a larger proportion of attempted items than deferred items (71% versus 40%; p < 0.001), and indicated a higher mean confidence in responses to items they answered correctly compared with items they answered incorrectly (70 versus 46; p < 0.001). They spent longer reviewing items they had answered incorrectly than correctly (8.3 versus 4.0 seconds; p < 0.001), and paid particular attention to items for which the attempt/defer decision and accuracy were discordant (p < 0.01). The amount of time required to make a decision on whether or not to answer a test question was also related to reviewing time. Conclusions Medical students showed a robust ability to accurately and consciously self‐monitor their likelihood of success on multiple‐choice test items. By focusing their subsequent self‐regulated learning on areas in which performance and self‐monitoring judgements were misaligned, participants reinforced the importance of providing learners with opportunities to discover the limits of their ability and further elucidated the mechanism through which test‐enhanced learning might be derived.     

咽喉表面麻醉慢诱导气管内插管在老年病人麻醉中的应用研究

目的观察咽喉表面麻醉慢诱导气管内插管对老年患者的影响。方法 66例择期行上腹部手术患者,随机分为咽喉表面麻醉慢诱导气管内插管组（观察组）和快速诱导插管组（对照组）,每组各33例,观察两组诱导前（T0）及诱导后（T1）、插管即刻（T2）、插管后5min（T3）的平均动脉压和心率、镇痛效果和不良反应。结果与T0比较,观察组诱导开始后各时点MAP、HR处于平稳状态,无显著性差异;与T0比较,对照组T1时MAP明显下降（P〈0.05）;T2、T3时MAP、HR皆明显上升并持续（P〈0.05）;与观察组比较,对照组T2、T3的MAP、HR均显著增高（P〈0.05）;观察组在插管期间1例出现心动过缓,对照组3例出现室性早搏;观察组病人可较好地耐受气管导管。结论咽喉表面麻醉慢诱导气管内插管对老年人更安全。     

咽喉表面麻醉慢诱导气管内插管在老年病人麻醉中的应用研究

目的观察咽喉表面麻醉慢诱导气管内插管对老年患者的影响。方法 66例择期行上腹部手术患者,随机分为咽喉表面麻醉慢诱导气管内插管组（观察组）和快速诱导插管组（对照组）,每组各33例,观察两组诱导前（T0）及诱导后（T1）、插管即刻（T2）、插管后5min（T3）的平均动脉压和心率、镇痛效果和不良反应。结果与T0比较,观察组诱导开始后各时点MAP、HR处于平稳状态,无显著性差异;与T0比较,对照组T1时MAP明显下降（P〈0.05）;T2、T3时MAP、HR皆明显上升并持续（P〈0.05）;与观察组比较,对照组T2、T3的MAP、HR均显著增高（P〈0.05）;观察组在插管期间1例出现心动过缓,对照组3例出现室性早搏;观察组病人可较好地耐受气管导管。结论咽喉表面麻醉慢诱导气管内插管对老年人更安全。     

Can nearly finished medical students interpret their professional literature?

The ability of senior medical students to interpret clinical research articles was examined by means of a written examination based upon two papers from general medical journals. The subjects of the articles were a diagnostic test and a therapeutic trial respectively. Knowledge of basic methodological and statistical concepts mentioned in the articles was in 86% of the students examined (n = 90) below the minimal level required for correct interpretation. 60% of the participants could not correctly apply the results mentioned in the diagnostic paper to a written clinical problem, and 11% could not apply the result of the therapeutic trial. From the reasons the participants gave for their decisions it appeared that 77% and 35% respectively had not been able to interpret the articles correctly. A comparison between self-rated knowledge and results of the test showed that the students tended to overestimate their knowledge. Knowledge of basic concepts of clinical epidemiology and statistics of these nearly graduated medical doctors is insufficient, and many of them cannot interpret clinical research articles correctly.     

Emergency tracheal intubation without drugs: outcome and one-year survival of medical patients not in cardiac arrest

Non-medicine-assisted tracheal intubation in prehospital trauma is associated with a dismal prognosis. We wished to study the outcome of medical patients who underwent non-medicine-assisted tracheal intubation. This retrospective study of patients attending our university hospital emergency department was conducted over seven years. The tracheal intubation database was analysed to identify medical patients not in cardiac arrest undergoing tracheal intubation without medicines. Intensive care unit, hospital, 12-month mortality and patients' residence at 12 months were recorded. Eighty patients were identified who met inclusion criteria. The most common reason for intubation was definite airway compromise due to decreased conscious level (62.5%), then respiratory failure (26.3%) and finally potentially compromised airway due to a decreased conscious level (11.2%). Eighty-eight percent of patients with a definitely compromised airway were successfully intubated at first attempt compared with 66.7% of patients with a potentially compromised airway or respiratory failure (P= 0.03). Of 75 patients with complete data, 30 (40%) were survivors at 12 months, with all but two (6.7%) living at home. Non-medicine-assisted laryngoscopy leads to an increased first time tracheal intubation failure rate in patients with intact airway reflexes and, therefore, cannot be recommended as best practice.     

Clinical audit: optimal positioning of endotracheal tubes in neonates

BACKGROUND: The malposition of endotracheal tubes (ETTs) can be associated with endo-bronchial intubation or accidental extubation. A variety of methods have been reported for predicting insertional length (IL) including weight, nasal-tragus length (NTL) and sternal length (STL) measurements. In our unit no consistent predictor method was being used. AIM: To audit the proportion of endotracheal tubes that required a significant position change after oral intubation. Our standard set was that the endotracheal tube should be in a satisfactory position in > 80% of cases. If not met, practice would then be re-audited after a consistent predictor method had been implemented. METHODS: Data regarding changes in endotracheal tube position were collected. Significant position changes were defined as adjustments > 0.5 cm. RESULTS: Twenty two babies were included in the initial audit, and only 73% of endotracheal tubes had a satisfactory position. Thirty six babies were included in the re-audit and when the nasal-tragus length predictor was used, 94% of endotracheal tubes had a satisfactory position, meeting the standard. CONCLUSION: The nasal-tragus length predictor improved the accuracy of endotracheal tube positioning after oral intubation. It is a simple, fast, reproducible method and can be used in everyday practice to help avoid significant endotracheal tube malposition.