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Invasive blood pressure measurements were performed in the common femoral- and popliteal artery of six limbs with occlusion of the superficial femoral artery during upright exercise (heel raising) and intraarterial α-receptor blockade. Femoral blood flow was obtained by an indicator dilution method injecting 131 RISA into the femoral artery and sampling from the popliteal artery. Exercise increased femoral blood flow from an average of 184 (SE±27) cm3·min−1 at rest to 531 (SE±61) cm3·min−1 during a 40° head up tilt.Intraarterially induced α-receptor blockade caused a further increase in blood flow to 685 (SE±86) cm3·min−1 during exercise.Changes in collateral arterial resistance was calculated relative to the supine resting value. During exercise a decrease of 24% (SE±13) was observed. After α-receptor blockade and exercise collateral resistance decreased by 46% (SE±12).The results indicate that the passive head-up tilt induced a constriction of the collateral arteries which is abolished by heel raising exercise (ie standing on tip toe). It seems, however, that during these circumstances there still remains some α-receptor mediated constriction of the collateral arteries which is blocked by intraarterially injected α-receptor blocking agents. [ABSTRACT FROM PUBLISHER]

Resistance in collateral arteries bypassing an occlusion of the superficial femoral artery was studied in five patients before and during epidural blockade. The patients were placed on a tilt table and the measurements were performed with the patients both in supine and tilted position (40° head up). Arterial blood pressure was measured directly in the brachial, common femoral and popliteal artery. Relative and absolute blood flows were calculated as the relative change in arteriovenous oxygen difference and by an indicator dilution technique.Tilting caused a decrease in relative leg blood flow of 28%. The relative pressure gradient between the femoral and popliteal artery did not change significantly. Calculated relative collateral resistance increased by 49%.During epidural blockade blood flow increased by 39% in supine position corresponding to a decrease in collateral resistance of 22%.During blockade tilting caused a decrease in relative blood flow of 22% compared with the value in supine position. The relative pressure gradient over the occluded superficial femoral artery decreased by 14%. The corresponding calculated relative collateral resistance increased by 14%.The results indicate that the tilt induced constriction of the collateral arteries is mainly neurogenically mediated via the lumbar sympathetic chain, whereas local mechanisms only seems to play a minor role. [ABSTRACT FROM PUBLISHER]

The effect of circulatory arrest of the calf and foot and head-up tilt upon pressure gradient over the thigh and distribution of muscle blood flow in the thigh was studied in 14 patients with occlusion of the superficial femoral artery. In the supine position circulatory arrest just below the knee initially reduced the directly measured mean arterial pressure gradient over the thigh by about 30% indicating that a similar proportion of total leg blood flow supplied the calf and foot. Local muscle blood flow was measured by the local 133Xe washout technique proximally and distally in the thigh muscle. Total leg blood flow was measured by an indicator dilution technique. During 10 min of circulatory arrest of the calf and foot local muscle blood flow in the thigh increased by approximately 35% proximally and distally. Total leg blood flow remained unchanged and the pressure gradient was reduced by about 10% as compared with that before tourniquet. During head-up tilt local muscle blood flow in the thigh decreased by about 30% proximally and distally. Total leg blood flow also decreased by about 30%. Circulatory arrest below the knee did not alter this response. These findings indicate that blood flow changes uniformly in the thigh during head-up tilt and during tourniquet on the calf. Furthermore blood flow to the calf appears only to account for 30% of the arterial pressure drop over the collateral arteries in the thigh, indicating that thigh blood flow is of major importance for the pressure gradient over the collateral arteries. [ABSTRACT FROM PUBLISHER]

The effect of head-up tilt on leg blood flow and segmental arterial blood pressures was studied in 21 patients with occlusion or severe stenosis of the common or superficial femoral artery. Arterial pressure was measured directly in the brachial artery, common femoral artery and popliteal artery. Relative change in blood flow in the leg during tilt was estimated by changes in arterio-venous oxygen differences and by the indicator dilution technique in nine patients.Head-up tilt caused a decrease in leg blood flow of 36% corresponding to an increase in total vascular resistance of 57%. Tilt did not change the pressure gradient from femoral to popliteal artery in the patients with occlusion of the superficial femoral artery, indicating that the flow resistance offered by the collateral arteries had increased. In a bilateral sympathectomised patient the increase in collateral resistance was almost absent indicating that the constriction of the collateral arteries is mainly mediated via sympathetic vasoconstrictor fibres. [ABSTRACT FROM PUBLISHER]

Background: Respiratory syncytial virus (RSV) hospitalization is associated with wheeze., Objective: To examine the influence of maternally derived RSV neutralizing antibodies in cord blood on RSV hospitalization and recurrent wheeze in infancy., Methods: Among children from the Danish National Birth Cohort, we selected a subcohort of 459 randomly selected children, 408 children with RSV hospitalization, 408 children with recurrent wheeze, and all 289 children who experienced both RSV hospitalization and recurrent wheeze. The influence of cord blood RSV neutralizing antibodies was examined as predictors for (1) RSV hospitalization, (2) RSV hospitalization after recurrent wheeze, (3) recurrent wheeze, and (4) recurrent wheeze after RSV hospitalization., Results: Neutralizing antibody levels were inversely associated with RSV hospitalization in infants below 6 months of age (adjusted incidence rate ratio [IRR], 0.74; 95% CI, 0.62-0.87), and also inversely associated with RSV hospitalization in infants with recurrent wheeze (IRR, 0.83; 0.71-0.97). In contrast, neutralizing antibody levels were directly associated with an increased risk of recurrent wheeze in infants below 6 months of age (IRR, 1.28; 1.04-1.57) and with an increased risk of recurrent wheeze after RSV hospitalization in infants below 6 months of age (IRR, 1.44; 1.10-1.90)., Conclusion: Maternally derived RSV neutralizing antibodies protect infants against RSV hospitalization, and also when the infant has recurrent wheeze. However, high maternally derived RSV neutralizing antibody levels were associated with an increased risk of recurrent wheeze.

The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553 patients, 51 (9%) of whom died within the first 48 hours. Of the 502 patients who survived for more than 48 hours, 109 required ICU therapy for more than 48 hours, whereas 393 patients were in the ICU for less than 48 hours. The incidence of preoperative risk factors was similar for the two groups. The cumulated survival rates for the two groups were 68% and 92% at 1 months, 52% and 88% at 1 year, and 60% and 33% at 6 years, respectively. This significant difference was primarily related to renal, pulmonary, and cardiac complications. However, assessment of the most severe complications and risk factors combined failed to permit identification of patients in whom the perioperative survival rate was 0%. Even 20% of patients with multiorgan failure survived for 6 months. Of those patients who needed ICU therapy for more than 48 hours, 41 (38%) were alive at the end of 1988. In response to a questionnaire, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems.

Arterial injuries represent a formidable challenge to surgeons working in war zone conditions. A series of 23 consecutive patients with combat wounds from the Afghan conflict with acute arterial injury were treated at the ICRC hospital in Peshawar. The mean injury-treatment delay (lag time) was 34 hours, with 14 of the 23 patients (60%) treated more than 12 hours after injury. The overall amputation rate was 65%, but only 22% for patients revascularized within 12 hours of injury and 93% for those undergoing surgery after 12 hours. This was a highly significant statistical difference (Chi-square > 13.0, p < 0.005). We recommend attempting revascularization procedures only in patients seen within 12 hours of sustaining a military-type injury to an artery in an extremity.

During 1979-1988 218 patients were operated on for ruptured abdominal aortic aneurysm. On admission 110 patients (50%) were in shock. Patients with a systolic blood pressure less than 100 mmHg, anuria on admission, peroperative bleeding of more than five litres and aged more than 70 years had an increased mortality. The intraoperative mortality was 15% and the postoperative mortality 21%. The perioperative mortality decreased from 45% in 1979 to 32% in 1988. The most frequent complications were renal failure and respiratory insufficiency, both were associated with a mortality of more than 50%. The five year survival was 48%. This study has revealed that patients with ruptured abdominal aortic aneurysm have an acceptable prognosis. The investigation emphasizes the importance of early diagnosis and elective operation to avoid rupture.

Between 1979 and 1988, 656 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed in 287 patients (44%) and acute operation in 369 patients. A ruptured aneurysm was found in 218 patients (33%). Patients with arteriosclerotic heart disease, hypertension, impaired renal function or chronic pulmonary disease showed an increased perioperative mortality. Development of postoperative cardiac and renal complications could not be related to previous cardiac or renal diseases. The major postoperative complications were renal failure in 81 patients (12%), pulmonary insufficiency in 77 patients (11%) and cardiac complications in 96 patients (13%). Failure of one or more organs occurred in 153 patients (23%) and the mortality rate for patients with multiorgan failure was 68%. Complications leading to reoperation occurred in 93 patients (14%). The perioperative mortality was 18.8%. The mortality for elective cases was 4.8%, for symptomatic cases 17.2% and 37% for ruptured aneurysms. The five-year survival rate was 48% for ruptured aneurysms, 70% for symptomatic cases and 75% for elective cases. After six months the life expectancy in these three groups of patients were identical and comparable to the expected survival for a sex and age matched control population.

From 1979-1988, 656 patients were operated for abdominal aortic aneurysm. The perioperative mortality was 18%. The mortalities for elective, symptomatic and ruptured aneurysms were 5%, 17% and 38% respectively. The overall five year survival rate was 58%. In 87% of the patients one or more risk factor was found. Survival was unaffected in patients with a single risk factor, whereas patients with two or more risk factors had lower five year survival. Postoperative organ failure increased the perioperative mortality and the five year survival in patients with multiorgan failure was 20%. In view of the fact that 56% of the patients are operated on as emergencies, this study stresses the importance of early diagnosis and elective treatment.

Among 656 patients undergoing surgery for abdominal aortic aneurysm, 81 patients (12%) developed postoperative renal failure. Before operation hypotension and shock occurred in 88% of the patients with ruptured aneurysm, whereas none of the patients operated electively were hypotensive. Dialysis was performed in 32 patients, while the remaining 49 patients were managed without dialysis. Within 30 days after the operation 47 patients (58%) had died. There was no difference in mortality between patients in dialysis and patients managed without dialysis. Thirteen patients died during follow-up. In six cases the death was caused by renal failure only or in combination with failure of other organs. Analysis of the cumulative survival shows that, if the patients survive the postoperative period, their life expectancy is comparable to that of patients without renal complications.

We studied the effect of external application of 35-45 mmHg negative pressure around the thigh on toe blood pressure and skin blood flow in nine patients with occlusion of the superficial femoral artery and rest pain/severe intermittent claudication. The systolic toe blood pressure increased from 32 (range 5-70) mmHg before treatment to 57 (42-75) mmHg (p less than 0.05) during negative thigh pressure and 44 (range 10-88) mmHg after treatment. In addition, the gain in toe blood pressure tended to be greater the lower the pre-test toe pressure was, correlation coefficient r = 0.52 (p greater than 0.05). Relative skin blood flow, measured in the first toe interstice by the 133Xe wash-out method, increased by 304 (range 86-767) percent (p less than 0.05) during the test period compared to the mean wash-out rate obtained before and following the test period. Heart rate, systemic blood pressure, skin temperature, serum protein and haematocrit measured during each phase of the study were similar. We conclude that 35-45 mmHg negative pressure around the thigh in patients with occlusion of the superficial femoral artery induce increased blood perfusion in the foot, possibly due to changes in collateral arterial resistance in the thigh.

From 1983-1987, 388 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed on 171 patients (44%) with a mortality of 2.9%. Emergency operation was done in 277 patients of whom 132 (34%) had ruptured aneurysms. The mortality for ruptured aneurysms was 36% and 21% for patients operated on as emergencies without signs of rupture of the aneurysm. The five year survival rate was 75% after elective operation, 60% after emergency operation and 40% after operation for ruptured aneurysm. The high mortality after emergency operation for abdominal aortic aneurysm confirms the importance of early diagnosis and elective operation before rupture occurs.

The effect of intra-arterially phentolamine inducing alpha-receptor blockade upon the resistance in collateral arteries bypassing an occlusion of the femoral artery was studied in five patients. The patients were placed on a tilt table and the measurements were performed with the patients in supine position and titled 40 degrees (head-up). Arterial blood pressure was measured directly in the brachial-common femoral-and popliteal artery. Relative blood flow was calculated as the relative change in arterio-venous oxygen saturation. Head-up tilt caused a decrease in blood flow of about 35% corresponding to an increase in total vascular resistance of 38%. Resistance in collateral arteries increased by 45%. In supine position alpha-receptor blockade reduced collateral resistance by 17%. However, the title-induced constriction of the collateral arteries was blocked by 87%. The results indicate that the constriction of the collateral arteries bypassing an occlusion of the superficial femoral artery is mainly mediated via sympathetic adrenergic vasoconstrictor fibres.

The vascular response in the lower extremities to 40 degrees head-up tilt was studied in 5 patients with occlusion of the superficial femoral artery and maturity onset diabetes mellitus with symptoms suggesting autonomic neuropathy. The pressure measurements were performed via catheters placed in the brachial artery, femoral artery and vein and popliteal artery and vein. Relative blood flow was calculated as the relative change in arterio-venous oxygen saturation. Absolute blood flow in the common femoral artery was measured by an indicator dilution technique. Resistance of the collateral arteries increased by 40% during head-up tilt compared with horizontal position. Total leg resistance increased by 24%. Vascular resistance did not change below the knee. Intra-arterial alpha-blockade abolished the increase of vascular constriction in the leg during head-up tilt indicating that alpha-adrenergic tone was present in limbs studied.

Direct measurement of the femoral artery pressure before operation has been used to predict the postoperative change in ankle and toe pressure in 102 limbs (83 patients) that underwent aortoiliac surgery for the treatment of atherosclerotic occlusion or stenosis affecting both the aortoiliac and femoral artery segments. Rest pain or gangrene was present in 74 limbs. In 26 other limbs simultaneous aortoiliac and femoral artery reconstructions were performed. The changes in both toe and ankle pressures could be confidently predicted from the preoperative data. A predicted toe pressure of lower than 25 mm Hg was associated with a high probability that amputation would be required. The chances of an amputation were less than 3% if a toe pressure higher than 40 mm Hg was predicted. If the predicted ankle pressure index was lower than 0.56, there was a 90% chance that intermittent claudication would persist. Measurement of the femoral artery pressure allows prediction of the toe and ankle pressure response to surgery to be made with sufficient accuracy to permit a preoperative decision to be made between the need for a single-level or a two-level arterial reconstruction: no patients who had an aortoiliac reconstruction needed a subsequent downstream repair of the femoral segment.

Thirty-six legs in thirty-three diabetic patients with ischemia at rest and multiple level arterial disease were studied preoperatively. Direct intraarterial femoral and popliteal artery blood pressures were measured together with indirect arm and foot blood pressures. Based on the systolic segmental pressure gradients it was predicted preoperatively whether it was necessary to make a one- or two-level reconstruction. The ankle pressure measured one month postoperatively correlated well with predicted values. Of the seventeen occlusions within the observation time hemodynamic factors played an important role in eleven cases. In the femoro-crural segment one occluded in which an iliac stenosis with a pressure gradient of 28% had been disregarded. In the femoro-popliteal above knee segment four occlusions occurred in cases where the postoperative ankle pressures were less than 80% of the preoperatively predicted value, suggesting stenosis at the anastomosis. A popliteal to ankle gradient of 39% was measured preoperatively in the fifth case which occluded 2 months postoperatively. In the aortofemoral segment five occlusions occurred all having femoral to ankle pressure gradients exceeding 40% of femoral artery pressure. Retrospectively, seven of the failures might have been prevented by two-level reconstructions and four failures by a secondary arterioplasty.