Different low constant flows can equally determine the lower inflection point in acute respiratory distress syndrome patients.

Among the possible techniques to obtain the pressure-volume (P x V) curve at the bedside the low constant flow (CF) is the easiest and quickest one. However, the best value for CF to perform a good semi-static P x V curve is still to be determined. The purpose of this study was to evaluate the influence of 4 different CFs (1, 2, 5, and 10 L/min) on determination of lower inflection point of the P x V curve (L-Pflex) and upper inflection point of the P x V curve (U-Pflex) on the maximum slope and on the inspiratory work of breathing (up to volume of 1.35 L; inspiratory work L/cm H2O), comparing the volume estimated from the CF with the measured volume obtained by the respiratory inductive plethysmograph. The design was a prospective study, and the setting was an adult medical intensive care unit of a university hospital. There were 7 acute respiratory distress syndrome (ARDS) patients, less than 5 days of installation, after the standardization of lung volume history received sequentially from 4 different low inspiratory CFs in 2 trials. The P x V curve lasted from 73 +/- 1.6 s (1 L/min) to 8.8 +/- 0.69 s (10 L/min). The L-Pflex differed in the 2 performed trials (p = 0.04). There was no difference of L-Pflex among the 4 CFs comparing the 3 methods (p = 0.072) used for its calculation as well as comparing the estimated and the measured volume (p = 0.456). The maximum slope decreased significantly while increasing the flow from 1 to 10 L/min just in the estimated volume (p = 0.03). The inspiratory work did not increase with the increment of the flow either in the estimated volume (p = 0.217) or in the measured volume (p = 0.149). The U-Pflex differed among the trials (p = 0.003) and the methods used for its calculation (p < 0.01). Constant flows from 1 to 10 L/min can equally determine L-Pflex in ARDS patients and is an easy and quick way to obtain the L-Pflex in order to optimize positive end expiratory pressure (PEEP) in ARDS patients.

[Role of the process of endothelium formation on the wall of the aortic prosthesis in protection against infection. Experimental study in dogs]. / Rôle du processus de formation d'endothélium sur les parois de la prothèse de l'aorte dans la protection contre l'infection. Etude expérimentale sur des chiens.

An experimental canine model was developed in order to evaluate the role of endothelialization of aortic prostheses for protection against septicemic infection and the utilization of 131I radiolabeled bacteria for vascular experimentation. Two groups of dogs were submitted to insertion of a dacron prosthesis segment in the abdominal aorta with subsequent infusion of inert 131I radiolabeled bacteria. In the first group ("A"), formed by five dogs, the infusion was made 30 minutes after the insertion of the prosthesis and in the second group ("B"), formed by four dogs, in a new surgery performed 12 weeks after. Fragments of the animals' prostheses and aortas were collected after 30 minutes of septicemia and analyzed by scan electron microscopy and submitted to reading of radioactivity uptake by a well-type counter. The microscopy recognized a complete endothelialization of the prostheses of dogs of group "B" 12 weeks after their insertion. Statistical analysis comparing fragments of non-endothelialized prostheses, of endothelialized prostheses and aortas demonstrated that the lower radioactivity uptake of the endothelialized prostheses in relation to non-endothelialized ones was significant (p = 0.0143) and that there was no significant statistical difference in uptake in the aortas and in endothelialized prosthesis (p = 0.3173). It was, therefore, concluded that prosthesis endothelialization fully protected them against septicemic infection; bacteremia contaminated all the non-endothelialized prostheses; there was no bacterial adhesion in the endothelialized prostheses and the use of bacteria labeled with radioisotope 131I is appropriate for the study of infections in vascular prosthetic devices.

Embolia de membros superiores / Upper limb arterial embolism

As embolias arteriais dos membros superiores correspondem a 16 a 32 'por cento' dos casos de obstrução arterial embólica periférica. Os autores analisaram 34 casos de embolia arterial em membros superiores, atendidos de janeiro de 1991 a dezembro de 1993. A idade variou entre 38 a 84 anos (mediana = 62 anos). Quinze pacientes eram do sexo masculino e 17 do feminino. A etiologia da embolia foi na grande maioria dos casos bem definida, sendo que a principal causa foi a fibriliação atrial (81 'por cento'). A oclusão da artéria braquial foi a mais frequente (62 'por cento'). Todos os pacientes desta série apresentavam isquemia de membro, sendo leve em 16 casos (47 'por cento') e grave nos outros 18 (53 'por cento'). Nenhum paciente estava com gangrena à admissão. A maioria dos pacientes apresentavam tempo de isquemia entre o início do quadro e da liberação do fluxo arterial entre 6 a 12 horas (40 'por cento'). Uma paciente foi tratada clinicamente. Todos os outros foram submetidos a embolectomia braquial com catéter de Fogarty. Empregou-se a fasciotomia em um paciente devido a presença de síndrome compartimental. Dois pacientes faleceram, no pós-operatório imediato, um por embolia mesentérica e o outro por infarto miocárdico. A recuperação dos batimentos arteriais foi obtida em todos os pacientes. Em três casos houve oclusão pós-operatória, reoperados com sucesso. Em nenhum caso observou-se alteraçöes metabólicas que comprometessem o estado geral do paciente e que pudessem ser relacionadas à reperfusão do membro superioe isquêmico. A preservação do membro foi obtida em todos os doentes. Concluímos que em casos de embolia de membro superioe, apresentando-se o paciente em boas condiçöes clínicas e com o membro superior sem necrose instalada, vale a pena a realização da embolectomia com catéter de Fogarty, devido aos bons resultados quanto à manutenção do membro e batimentos arteriais, além de baixos índices de complicaçöes derivadas do procedimento cirúrgico.

Arterial embolectomy in lower limbs.

Arterial embolisms in the lower limbs occur frequently, and are of great interest to the vascular surgeon. The authors studied 159 cases of arterial embolisms in lower limbs from January 1991 to July 1993. Ages varied from 12 to 98, with a mean of 58. Eighty patients were male and 78 were female. In most cases, etiology of the embolus was well-established, and mainly caused (78 percent) by atrial fibrillation. Occlusion was most frequent in the femoral artery (53.4 percent). All patients presented severe lower limb ischemia, but not gangrene, on admission. The duration of ischemia, between the onset of symptoms and the liberation of arterial flow, was in most patients (67.9 percent) less than 24 hours. All patients were submitted to lower limb embolectomy with the Fogarty catheter, of which 70.9 percent were done through the femoral artery. Fasciotomy was performed on 48 patients due to a compartimental syndrome. Nineteen patients died immediately after operation; 68.4 percent due to heart failure. Twenty-three (16.4 percent) of the 140 surviving patients (150 operated limbs) were submitted to amputations after the occlusion of artery branches, which had undergone embolectomies. One hundred and twenty-seven limbs (84.6 percent) were preserved in 117 patients (83.5 percent). Eleven cases (7.3 percent) required repeated surgery with the Fogarty catheter. The patients with muscle tenderness, paralysis, or ischemia lasting longer than 24 hours had worse results in relation to the preservation of the limb (p < 0.05). We conclude that patients who present lower limb embolisms, are in good clinical condition, and who do not have any necrosis in the limbs, have good outcomes as to limb preservation, along with low complication rates, after embolectomy with the Fogarty catheter. Limb preservation was significantly higher in patients who did not present muscle tenderness, and who had normal motor activity and a ischemia duration of less than 24 hours.

Aneurisma anastomótico da artéria mesentérica inferior: relato de um caso / Anastomotic aneurysm of the inferior mesenteric artery: case report

Os autores relatam caso de um homem com 56 anos de idade que se queixava de dor na regiäo lombar com irradiaçäo para os membros inferiores por três meses, dois anos após a correçäo de aneurisma da aorta infra-renal. Após estudos diagnósticos - como tomografia computadorizada - e angiográficos, o paciente foi encaminhado ao centro cirúrgico com diagnóstico de falso aneurisam do terço médio da prótese. No ato cirúrgico verificou-se que o falso aneurisma teve origem devido à deiscência da anastomosoe artéria mesentérica inferior que havia sido implantada na prótese.

[Non-iatrogenic trauma of the brachial artery]. / Traumatismos não iatrogénicos da artéria braquial.

Brachial artery trauma are treated quite frequently in the emergency units. Between January 1987 and December 1990 we studied prospectively 50 patients with brachial artery trauma at the Hospital das Clinicas, of University of Sao Paulo. The patients mean age ranged from 2 to 64 years. Males were predominant with 46 patients. Most of them were white (66%). Penetrating injuries were the most frequent. Most of these injuries were caused by gunshot wounds or stabing. Absence of distal palpable pulses was the predominant finding among the clinical features (94%). 74% of the patients do not present important ischemia. The right side was more affected (34 patients). 14 patients had concomitant nerve injury. 35 patients (70%) were submitted to arterial reconstruction with saphenous vein. 12 patients (24%) had end-to-end vascular anastomoses. 3 patients (6%) were submitted to brachial artery ligation. 2 patients underwent simultaneous median nerve repair. In 3 patients we used fasciotomy. 6 patients developed arterial occlusion following vascular reconstruction and in one of them it was necessary to perform amputation. 2 patients had wound infection with saphenous vein repair disruption. Both were treated with brachial artery ligation and one underwent amputation. One patient died on the post operative period owing to associated lesions. Limb preservation was achieved in 47 patients (94%). 33 (70.2%) had no neurological deficit and 14 (29.7%) had some degree of neurological deficit. None of the patients had venous hypertension at the time of discharge.

Trauma to arteries of the forearm.

Trauma to arteries of the forearm corresponds to 20% of total arterial trauma. The authors analyzed 24 patients with non iatrogenic trauma of the forearm arteries, cared for from January 1987 to December 1990. All patients were male, trauma by penetrating instrument was the most frequent, with 21 cases (87.5%), absence of pulses was the most frequent clinical manifestation (62.5%), fifteen patients did not present ischemic manifestations (54.2%) and half of the patients did not exhibit neurological symptoms. Injury to only one artery was found in 11 cases, five of them in the radial artery (20.8%), five in the ulnar artery (20.8%) and one in the interosseous artery (4.2%). Concurrent injury to the radial and ulnar arteries was found in 13 cases (54.1%). Regarding nervous impairment, injury to the radial nerve was found in four cases (16.6%) and of the median and ulnar nerves, one case in each (4.1%). All patients with concurrent injury to the ulnar and radial arteries (13) were submitted to arterial restoration. The 11 patients with injury to a sole artery of the forearm were managed as follows: ligature of the interosseous artery in one case, ligature of the radial artery in four cases, raphe of the radial artery in one case, ligature of the ulnar artery in three cases, restoration of the ulnar artery using a segment of the v. saphena in the two cases in which the Allen test had been positive. One patient died in the immediate postoperative period as a result of multiple organ failure due to polytraumatism.(ABSTRACT TRUNCATED AT 250 WORDS)