直视医学临床见习难——浅析面临困境及其对策

随着社会发展、医学模式的转变，医疗改革和学校扩招政策的实施，传统的临床见习教学遇到了前所未有的冲击与困惑。本文根据临床见习现状进行分析，力求找到最佳的解决方法。     

Noninvasive Intracranial Cerebral Flow Velocity Evaluation in the Emergency Department by Emergency Physicians

Transcranial Doppler (TCD) is an accepted modality for the evaluation of cerebral blood flow velocities. OBJECTIVES: The purpose of this study was to test the feasibility of bedside TCD measurement in the emergency department (ED) with critically ill, intubated patients. METHODS: A prospective convenience sample of patients presenting to a university hospital over a two-month period underwent TCD evaluation of the middle cerebral artery. Intubated patients with head trauma and any patient requiring tracheal intubation were eligible. A 2-MHz Doppler probe was positioned over the temporal bone to acquire blood flow velocities. An emergency medicine resident and research assistant obtained measurements. Continuous TCD tracings were recorded on a video cassette recorder tape for quality assurance review and data collection. Vital signs and therapeutic interventions were also recorded. Flow velocities were measured in cm/s; the peak Resistance Index (RI) was calculated for each patient. RESULTS: A total of 30 patients were enrolled in the study. Adequate tracings were obtained in 25 patients (83%) without a disruption of resuscitation. Tracings could not be obtained in five patients; they were listed as TCD failures. However, in two of these patients, adequate flow velocity tracings were obtained after resuscitation. Four patients were evaluated during tracheal intubation. One patient was monitored successfully during cardiopulmonary resuscitation. The median time required for data acquisition was 1.9 minutes. The mean highest RI for those who expired was 0.84. For those who survived, the mean highest RI was 0.52. The difference of 0.32 was statistically significant (p = 0.04). CONCLUSIONS: Noninvasive blood flow velocity monitoring of the middle cerebral artery using TCD is feasible in the ED when performed at the bedside on intubated patients with traumatic brain injury and others during tracheal intubation and resuscitation.     

Effects of tracheal extubation on coronary blood flow,myocardial metabolism and systemic haemodynamic responses

Global coronary blood flow and metabolism were measured in seven patients on the first postoperative day following coronary revascularization to test the hypothesis that tracheal extubation produces adverse haemodynamic responses akin to those observed during tracheal intubation. Regional coronary flow and metabolic measurements were made in five of the seven patients. Extubation from a continuous positive airway pressure (CPAP) of 5 cm H₂O was associated with a statistically significant rise in cardiac index from 3.44 ± 0.23 L · min^-1 · m^-2 to 3.73 ± 0.15L·min^-1 ·m^-2 related to an increase in stroke index, without significant changes in heart rate, mean arterial and pulmonary capillary wedge pressure. Consequently the changes in myocardial oxygen consumption (8.52 ± 0.55 to 8.85 ± 0.93 ml · min^-1) and coronary blood flow (172 ± 18 to 179 ± 17 ml·min^-1) were less prominent than those reported during intubation, where substantial rises in myocardial oxygen consumption and coronary flow occurred. Two patients experienced cardiac lactate production but there were no changes in systemic or coronary haemodynamics, nor were there clinical or electrocardiographic signs of ischaemia. We conclude that extubation does not appear to be associated with adverse systemic or coronary haemodynamic responses in patients following coronary bypass grafting. However, the revascularized myocardium may remain vulnerable to anaerobic metabolism in the immediate postoperative period. Pour savoir si comme ľintubation, ľextubation de la trachée provoque des perturbations hémodynamiques, on a mesuré le métabolisme et la circulation coronarienne globale chez sept patients, au lendemain ďun pontage aorto-coronarien. On a aussi calculé les valeurs régionales de ces mêmes variables pour cinq ďentre eux. Ľindex cardiaque de 3.44 ± 0.23 L · min^-1 · m^-2 sous pression positive en respiration spontanée (CPAP) de 5 cm. H₂O s’est élevé à 3.73 ± 0.15 L · min^-1 · m^-2 post-extubation avec une augmentation significative du volume ďéjection. La fréquence cardiaque et les pressions artérielles moyennes et capillaires pulmonaires n’ont pas changé. Ainsi ľaugmentation de la consommation ďoxygène du myocarde de 8.52 ± 0.55 à 8.85 ± 0.93 ml · min^-1 et celle du flot coronarien de 172 ± 18 à 179 ± 17 ml · min^-1 ont été moindres que celles, importantes, déjà observées lors de ľintubation. On a noté chez deux patients une production de lactate par le myocarde, sans changement de ľhémodynamic systémique et coronarienne non plus que de signe clinique ou électrocardiographique ďischémie. Donc, après un pontage coronarien, ľextubation ne semble pas causer ďeffet néfaste sur les circulations systémique et coronarienne, toutefois, le myocarde revascularisé peut demeurer sensible au métabolisme anaérobique.     

Absorption of Propranolol in Humans Following Oral,Jejunal, and Heal Administration

Pharmaceutical Research -     

Use of a double balloon enteroscope facilitates caecal intubation after incomplete colonoscopy with a standard colonoscope

BACKGROUND: Caecal intubation is a necessary step in the complete endoscopic evaluation of the colon. Studies have estimated that experienced colonoscopists may fail to reach the caecum in up to 10% of cases. AIMS: To evaluate the utility of the double balloon enteroscope used for complete examination of the colon in patients with incomplete standard colonoscopy. PATIENTS: Twenty consecutive patients with incomplete colonoscopies within the Veterans Affairs Palo Alto Health Care System. Mean age of 66 years (S.D.+/-12 years, range 46-84), 16 men. METHODS: Prospective single-centre case series on the caecal intubation rate using standard double balloon enteroscope technique in patients with previous incomplete conventional colonoscopy. RESULTS: Use of the standard double balloon enteroscope technique permitted complete colonoscopy to be achieved in 95% of the patients (19/20). Seven patients (35%) had significant pathology beyond the extent of the prior incomplete colonoscopy. We performed endoscopic mucosal resection, polypectomy or biopsy. The mean time to reach the caecum was 28 min (S.D.+/-20 min, range 6-90 min). The sedation was similar to conventional colonoscopy. No complications occurred. CONCLUSIONS: The double balloon enteroscope technology and technique can be used to complete examination of the colon in patients who were referred because of incomplete standard colonoscopy.     

Tracheal intubation under fluoroscopic control X ray-guided orotracheal intubation in three cases of impossible direct laryngoscopy

Three patients are described in whom it was impossible to visualise the larynx at direct laryngoscopy. Tracheal intubation was successfully and rapidly achieved with the aid of continuous fluoroscopy.     

Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation

Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg^-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg^-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.     

162例气管插管患者的气道管理

笔者通过报道162例气管插管患者的气道管理，阐述痰痂形成的原因：(1)气道干燥，湿化不够。(2)吸痰管插入深度不够，吸痰不彻底。管理措施：(1)用金霉素眼膏润滑吸痰管，使之易于插入，保证吸痰管插入深度超过插管远端3-5cm。(2)预防气道干燥，注重湿化效果，重视吸痰环节。认为气囊不需定时放气，只需不定时调整气囊压力。     

老年卧床病人鼻饲并发症的护理干预

目的　通过护理干预 (增加置入胃管深度、抬高床头、适宜鼻饲量及鼻饲速度 )预防鼻饲时出现的呛咳、食物反流、胃潴留以及吸入性肺炎。方法　将 16例老年卧床鼻饲患者随机分成四组 ,对照组给予教科书上常规的置管深度及鼻饲方法 ;实验一组 (A)给予常规置管深度 ,鼻饲时抬高床头 30～ 80cm ;实验二组 (B)置管深度延长 8～ 10cm ,实验三组 (C)置管深度延长8～ 10cm ,鼻饲时抬高床头 30～ 80cm(坐位或半坐位 ) ,保持该体位 30min。结果　四组病人比较呛咳 ,对照组与实验组 (A、B、C)P <0 .0 1,差异有统计学意义 ;食物返流率P <0 .0 5 ;胃潴留对照组与实验组P >0 .0 5 ,差异无统计学意义 ;吸入性肺炎对照组 2例 ,A、B组各 1例 ,C组无发生。结论　护理干预可以减少与预防鼻饲并发症的发生。