Regional wall mechanics and blunt traumatic aortic rupture at the isthmus.

OBJECTIVE: Blunt traumatic aortic injury (BTAI) is part of a spectrum of diseases termed acute aortic syndrome that accounts for 20% of road traffic accident related deaths. The injury has a complex aetiology with a number of putative mechanisms accounting for the injury profile, characteristics of which include a transverse primary intimal tear located at the aortic isthmus. We hypothesised that an understanding of regional aortic wall mechanics would contribute to an understanding of the aetiology of BTAI. METHODS: Samples of porcine aorta were prepared from ascending (A), descending (D) and peri-isthmus regions (I). A histological analysis of aortic wall architecture was performed at the site of attachment of the ligamentum arteriosum. Samples were mounted in a bubble inflation clamping rig, connected via a solenoid release valve to a compressed air reservoir. Using a pressure transducer and high-speed camera (1000fps) we collected data on wall thickness, rupture pressure and radial extension, allowing calculation of ultimate tensile stress. RESULTS: Histological analysis at the point of attachment of the ligamentum arteriosum to the isthmus shows some heterogeneity in cellular architecture extending deep into the tunica media. Wall thickness was significantly different between the three sampled regions (A>I>D, p<0.05). However, we found no difference in absolute rupture pressure between the three regions (kPa), (A, 300+/-28.9; I, 287+/-48.3; D, 321+/-29.6). Radial extension (cm) was significantly greater in A vs I (p<0.05), (A, 1.85+/-0.114; I, 1.66+/-0.109; D, 1.70+/-0.138). Ultimate tensile stress (kPa), (A, 3699+/-789; I, 3248+/-1430; D, 4260+/-1626) was significantly greater in D than I (p<0.05). CONCLUSIONS: The mechanism of blunt traumatic aortic rupture is not mechanically simple but must correspond to a complex combination of both relative motion of the structures within the thorax and local loading of the tissues, either as a result of their anatomy or due to the nature of the impact. A pressure spike alone is unlikely to be the primary cause of the peri-isthmus injury but may well be a contributory prerequisite.

Adverse effects of fluorescein angiography in hypertensive and elderly patients.

PURPOSE: To evaluate adverse effects in patients undergoing fundus fluorescein angiography (FA), and to assess the level of these adverse effects in hypertensive and elderly patients. METHOD: We carried out a retrospective study of 358 patients undergoing FA. They were assessed for adverse effects and their relationship to medical history, pre- and post-FA blood pressure and age. RESULTS: The overall adverse reaction rate (AR) was 11.2%, the majority (80%) of which involved nausea. There were no mortalities and no cases of anaphylaxis or cardiac arrest. Hypertension (systolic or diastolic) did not increase the AR. Interestingly, raised initial systolic blood pressure (BP) > or = 160 showed a statistically significant decreased AR compared with that for BP < 160 (7% versus 15%, respectively; p = 0.04). There was no statistical correlation between AR and age. CONCLUSIONS: FA is a relatively safe procedure, but serious side-effects have been reported in the past and therefore adequate measures need to be in place to cope with such emergencies. In our study, there was no increase in the incidence of adverse effects in patients who were hypertensive or elderly. Therefore, these patients should not be denied an important diagnostic procedure that may improve their quality of life purely because of hypertension or age.

Perspectives of relatives and health care workers on care of terminally ill patients in the UK.

Two parallel questionnaires were used to explore perceptions of healthcare workers (HCWs) and the relatives of terminally ill patients on the quality of care received by the patients. There was general agreement between the two groups of respondents in most of the assessed areas. The relatives, however were more satisfied with the control of pain and psychological symptoms than the HCWs, and the HCWs perceived the control of diarrhea, skin problems, and swallowing problems more positively than did the relatives. There also was some variation between the two groups in their perception of the care received by the relatives during visits at the hospital, with the relatives' group being more positive. Although HCWs reported that time to deal with patients and their families was inadequate, the relatives' group was generally satisfied with the standards in place.