Objectives: To investigate the effects of strenuous exercise on commonly used biochemical and haematological variables in subjects running the 2002 London marathon. Methods: 34 healthy volunteers (7 female, 27 male) were recruited for the study. Blood was taken before the start (at registration) and immediately after completion of the marathon. Samples were analysed for urea and electrolytes, liver function tests, creatine kinase (CK), CK-MB isoenzyme, myoglobin, troponin I, full blood count, a clotting screen, and D-dimers. The results before and after exercise were compared. Pearson's correlation coefficients were calculated for all variables. Results: Significant increases were found in CK, CK-MB, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and myoglobin following the marathon. However, there was no significant change in the level of troponin I. There was also evidence of activation of the coagulation and fibrinolytic cascades following the marathon, with a reduction in activated partial thromboplastin time, a reduction in fibrinogen, and an increase in D-dimers. Conclusions: The results confirm previous individual studies on marathon running and the biochemical and haematological tests routinely carried out in hospital. These are affected by prolonged exercise, and ''abnormal'' results in these tests may be normal after prolonged exercise and therefore not diagnostic of a disease process. The results of investigations in patients who have been exercising should be interpreted with caution.

Fibreoptic orotracheal endoscopy under general anaesthesia may be more difficult to perform if the upper airway cannot be fully cleared. We have studied the effectiveness of jaw thrust, lingual traction and the application of both manoeuvres simultaneously, in opening up the orolaryngeal airspace in 30 ASA group 1 or 2 patients aged between 16 and 70 yr undergoing elective general surgery requiring orotracheal intubation. Airway clearance was assessed fibreoptically at soft palate level by observing whether or not the uvula or soft palate was apposed to the base of the tongue, and at epiglottic level by observing whether or not the epiglottis was apposed to the posterior pharyngeal wall. Lingual traction with Duval's forceps cleared the tongue away from the uvula and soft palate significantly more times than did jaw thrust (P<0.05). Jaw thrust cleared the epiglottis away from the posterior pharyngeal wall more frequently than did lingual traction (P=0.052). Applying both jaw thrust and lingual traction simultaneously cleared the airway at both soft palate and epiglottic level in every patient. When used alone, jaw thrust and lingual traction fail to produce full airway clearance in a significant number of patients. Combined jaw thrust and lingual traction clears the airway more effectively but requires two assistants.

SummaryWe have followed the progress of 12 anaesthetic trainees as they learnt how to perform fibreoptic nasotracheal intubation with the aid of an endoscopic video camera system. Each trainee had a structured teaching session on a bronchial tree model, viewed an instructional videotape and then performed 20 nasotracheal intubations on anaesthetised oral surgery patients. Trainees were required to perform the endoscopies under full visual control and to demonstrate airway anatomy as they advanced the fibrescope. They were allowed up to two 2 1 2 min periods to complete nasotracheal endoscopy. All 240 endoscopies were completed within the time limit: 228 were completed within 2 1 2 min and 12 (5%) were completed during the second 2 1 2 min period. We constructed a group learning curve from the pooled data. The half-life of the curve was nine endoscopies. The best fit value for the first endoscopy time was 132 s, and after the 18th (two halflives) it was 49 s. We analysed the theoretical basis for deriving a learning curve from raw data. This information could form a rational basis for the design of fibreoptic training programmes using video imaging systems.

Objectives: To review the effects of exercise on haemostasis and examine the possible clinical sequelae of these changes. Methods: The search strategy included articles from 1966 to August 2002 using Medline and SportDiscus databases, and cross referencing the bibliographies of relevant papers. Results: Exercise results in activation of both the coagulation and fibrinolytic cascades, as shown by a reduction in whole blood clotting time and activated partial thromboplastin time, an increase in the activity of several components of the cascades, and an increase in fibrin degradation products. In vitro tests suggest that coagulation remains activated after fibrinolysis has returned to baseline levels. Conclusions: Both the coagulation and fibrinolytic cascades are stimulated by strenuous exercise, but the temporal relation between the two and its clinical significance remains to be clarified. Doctors and athletes should be aware of the haemostatic changes induced by exercise, and further work is needed to clarify the possible role of these changes in sudden cardiac death.H aemostasis is achieved through a delicate equilibrium between the coagulation and fibrinolytic cascades. All the components of these cascades exist in the circulation as inactive proteins, which are converted into their active enzymatic form when the cascades are activated. The intrinsic and extrinsic pathways merge to produce thrombin from prothrombin, which in turn stimulates the production of fibrin from fibrinogen. When fibrin becomes cross linked and combines with platelets, a clot is formed. This process is regulated by inhibitory mechanisms, including fibrinolysis, the process by which fibrin is broken down into soluble components. Abnormalities of haemostasis are implicated in the pathogenesis of several diseases, and many therapeutic processes alter the balance of haemostatic control.Regular exercise is generally associated with favourable alterations in risk from cardiovascular morbidity and morbidity, but strenuous exercise has been implicated in the pathogenesis of sudden death.1 2 The mechanism behind this is not clear. Exercise has been shown to affect both coagulation and fibrinolysis, and the relation between the activation of the two cascades has implications in patients at risk of developing intravascular thrombus. If exercise preferentially activates fibrinolysis, then it may be of benefit in these subjects, but if coagulation is preferentially activated, it may potentiate devastating occlusion of a coronary or cerebral vessel. The purpose of this article is to provide a summary of the evidence of the effects of exercise on haemostasis and to examine the potential implications of the findings. METHODThe database was obtained by a computerised search of Medline and SportDiscus from 1966 to August 2002, and cross referencing the bibliographies of articles found. Keywords used in the search were exercise, blood coagulation, blood coagulation factors, and fibrinolysis. FINDINGS CoagulationIt has been known for many years that blood...