Universal or selective screening of the neonatal hip using ultrasound? A prospective, randomised trial of 15,529 newborn infants.

The aim of this study was to evaluate whether universal (all neonates) or selective (neonates belonging to the risk groups) ultrasound screening of the hips should be recommended at birth. We carried out a prospective, randomised trial between 1988 and 1992, including all newborn infants at our hospital. A total of 15 529 infants was randomised to either clinical screening and ultrasound examination of all hips or clinical screening of all hips and ultrasound examination only of those at risk. The effect of the screening was assessed by the rate of late detection of congenital or developmental hip dysplasia in the two groups. During follow-up of between six and 11 years, only one late-detected hip dysplasia was seen in the universal group, compared with five in the subjective group, representing a rate of 0.13 and 0.65 per 1,000, respectively. The difference in late detection between the two groups was not statistically significant (p = 0.22). When clinical screening is of high quality, as in our study, the effect of an additional ultrasound examination, measured as late-presenting hip dysplasia, is marginal. Under such circumstances, we consider that universal ultrasound screening is not necessary, but recommend selective ultrasound screening for neonates with abnormal or suspicious clinical findings and those with risk factors for hip dysplasia.

Selective carotid angiography during cross-clamping of the descending thoracic aorta in pigs.

OBJECTIVE: To visualize the intra- and extracranial blood vessels during cross-clamping of the descending thoracic aorta. EXPERIMENTAL DESIGN: Experimental animal study. SETTING: Animal laboratory, University Hospital. MATERIALS: Seven pigs. INTERVENTIONS: Cross-clamping of the descending thoracic aorta for 30 minutes. METHOD: Selective carotid angiography was performed before, during and after cross-clamping. Venous filling time of internal- and external jugular veins, diameter of internal and external jugular veins and internal, external and common carotid arteries and contrast intensity were determined. RESULTS: During cross-clamping the blood flow velocity increased as demonstrated by decreased venous filling time and decreased contrast intensity. In addition, the diameter of the external jugular vein increased and the diameter of the internal carotid artery decreased during cross-clamping. No arteriovenous anastomoses could be detected during the experiment. CONCLUSIONS: Our results indicate increased intra- and extracranial blood flow during cross-clamping of the descending thoracic aorta in pigs.

Chylous complications after abdominal aortic surgery.

Two patients developed chylous complications following abdominal aortic aneurysm repair. One patient had chylous ascitis and was successfully treated by a peritoneo-caval shunt. The other patient developed a lymph cyst, which gradually resorbed after puncture. Chylous complications following aortic surgery are rare. Patients in bad a general condition should be treated by initial paracentesis and total parenteral nutrition, supplemented by medium-chain triglyceride and low-fat diet. If no improvement is observed on this regimen, the next step should be implementation of a peritoneo-venous shunt, whereas direct ligation of the leak should be reserved for those who are not responding to this treatment.

Regional distribution of blood flow during proximal aortic cross-clamping: an experimental study using coloured microspheres.

OBJECTIVE: To investigate the effect of thoracic aortic cross-clamping on blood perfusion of the brain, spinal cord, heart, muscular tissue and visceral organs. MATERIAL AND METHODS: Nine pigs underwent 30 min cross-clamping of the descending thoracic aorta. Multiple coloured microspheres (15.0 microm +/- 0.1) were infused into the left ventricle before and during aortic cross-clamping (XC) and after declamping (DC). Tissue samples were analysed by spectrophotometry. RESULTS: Blood perfusion of the middle and lower segments of the spinal cord was significantly reduced during aortic XC. Perfusion of the brain was not significantly altered by aortic XC, while perfusion of myocardium increased 3-fold. During XC, perfusion of the deltoid muscle and diaphragm increased 5-fold and 13-fold, respectively, while a decrease was found in the gluteus muscle. Renal blood flow was significantly reduced during XC. Finally, XC induced a significant decrease of perfusion in the bowel, spleen, liver and pancreas. CONCLUSION: During XC of the thoracic aorta, the perfusion of the muscular tissue was significantly increased proximal to the level of XC. The circulation of the brain was unchanged, probably because of autoregulatory mechanisms. Blood perfusion of the myocardium increased 3-fold during XC.

Quality of data reported on abdominal aortic aneurysm repair--a comparison between a national vascular and a national administrative registry.

OBJECTIVE: To study consistency of data and completeness of reporting in a national vascular registry, NorKar, and a national administrative registry, The Norwegian patient register (NPR). DESIGN: Comparative registry-based national study supplemented with a comprehensive control of patients registered in one major hospital. MATERIAL: All patients registered with a procedure-code for treatment of AAA in NorKar or NPR during 2001 or 2002, were included. METHOD: We compared the reporting of procedure-codes, diagnosis-codes and in-hospital deaths after treatment for abdominal aortic aneurysm (AAA) in the two registries to evaluate completeness. Consistency between procedure-codes and diagnoses were evaluated within both registries. Completeness of reporting to one NorKar Local Registry was investigated in more detail in one of the hospitals. RESULTS: Compared with the NPR numbers, NorKar contained 69% of the patients treated for AAA in Norway, while completeness for NorKar member hospitals was 84%. The detailed investigation in one of the hospitals showed a completeness of 91% and a false inclusion of 5.3% of all cases treated for AAA. The consistency between procedure-codes and diagnosis-codes was 93% in both registries. We found evidence of substantial underreporting of in-hospital deaths to NorKar in several hospitals. Overall reporting of early deaths to NorKar relative to completeness of reported cases was estimated to 72%. CONCLUSION: There is an underreporting of patients with AAA to NorKar according to the NPR numbers and a need for better control of procedure-diagnosis consistency in both registries. There seems to be a substantial underreporting of early deaths to NorKar. Introduction of unique patient-identifiable data could improve the quality of both registries by making matching of data possible.

Changes in hemodynamics and acid-base balance during cross-clamping of the descending thoracic aorta. A study in patients operated on for thoracic and thoracoabdominal aortic aneurysm.

AIM OF THE STUDY: In the clinical situation there is discrepancy between various investigations regarding the cardiac response of thoracic aortic cross-clamping. The aim was therefore to investigate the hemodynamic response and blood gases during proximal aortic cross-clamping (XC) in patients operated for descending thoracic and thoracoabdominal aortic aneurysm without circulatory support. PATIENTS AND METHODS: Altogether 51 patients operated on for thoracoabdominal (n=31) or descending thoracic aortic aneurysm (n=20) were included in the investigation. All patients were operated with aortic XC, but no circulatory support was applied. Hemodynamic variables and blood gases were recorded before and during XC. RESULTS: A significant increase in cardiac output during XC from 4.7 to 6.0 liters/min was observed (p<0.01). There was a similar percentual increase in heart rate and also the proximal systolic blood pressure increased. A metabolic acidosis occurred during XC. CONCLUSION: Cardiac output was significantly increased during XC in patients operated on for thoracoabdominal or descending thoracic aneurysm using direct aortic XC without circulatory support. Simultaneously, the heart rate was increased and there was a hyperdynamic circulatory state proximal to the aortic clamp. Redistribution of the blood volume in addition to catecholamine release may be responsible for the observed changes. These observations may influence the selection of operative strategy for some of these patients.

Problems related to previous thrombendarterectomy of the aorto-ilio-femoral arterial segment.

Early postoperative problems following aorto-ilio-femoral thrombendarterectomy include occlusion, bleeding and emboli. Technical details important for the prevention of these complications are discussed. Late problems include reobstruction, sexual dysfunction and aneurysm formation, the last complication being unusual following thrombendarterectomy. Late reobstruction is usually caused by progression of atherosclerosis and technical failures. Bypass grafting using synthetic material is usually the preferred method in redo aorto-ilio-femoral reconstruction since extensive dissection of the arteries is then avoided. We prefer a regular laparotomy for these operations. It might be an advantage to introduce ureteral stents making it easier to identify the ureter which may be surrounded by scar tissue following previous dissection. The creation of sufficient run-off is important. In several cases the procedure must therefore be supplemented with a profunda artery reconstruction. In case of localized and moderate obstruction PTA may be indicated for the relief of recurrent arterial obstruction following thrombendarterectomy.

[Vascular surgery in Norway in 1986]. / Karkirurgi i Norge 1986.

A questionnaire on vascular surgical activity in 1986 was sent to all Norwegian surgical departments (80). 78 units responded. Vascular surgery is not performed in the two hospitals who did not respond. Altogether 3,509 vascular operations were performed in 1986 (844 operations per million inhabitants). By comparison, 2,529 operations were performed in 1981, 2,039 in 1978 and 1,100 in 1975. The largest increase was recorded in operations for abdominal aortic aneurysm, carotid artery stenosis, arterial emboli and angio-access surgery. Elective vascular operations were performed in 41 departments, whereas an additional 16 did emergency vascular surgery only. 34% of the operations were performed by members of the junior staff. Differences between the five health regions have decreased since the investigation in 1981. The highest activity was observed in Health Region V, where 986 operations were performed per million inhabitants. Vascular surgical activity is increasing in Norway. This must be taken into account when estimating the number of residencies and staff positions for vascular surgery. The increasing need for vascular surgery should also influence priorities in our national health system.

Winner of the ESVS prize 1989. Microcirculation of the spinal cord during proximal aortic cross-clamping.

The relationship between the cerebrospinal fluid pressure (CSFP) and the microcirculation of the spinal cord was studied during cross-clamping (XC) of the thoracic aorta in pigs. CSFP was recorded via an intrathecal catheter. The microcirculation was measured by the laser Doppler technique using a needle probe inserted percutaneously into the spinal cord. A left thoracotomy was performed, and the thoracic aorta was cross-clamped for 30 minutes distal to the left subclavian artery. Prior to XC a pulsatile flux recording from the spinal cord (SCF) was observed. Following cross-clamping of the aorta SCF was dramatically reduced (P less than 0.001), then stabilised at 40% of base-line values. During XC, variations in CSFP were observed but these changes were not statistically significant. CSFP gradually increased to pre cross-clamp levels following release of XC (P less than 0.05). SCF increased 51% following removal of 1 ml of cerebrospinal fluid (P less than 0.05). By injection of 0.9% saline at body temperature SCF was totally inhibited at CSFP above 15 mmHg. Occlusion of the azygos vein increased CSFP 1.3 mmHg (P less than 0.05) whereby SCF decreased 58% (P less than 0.01). Following release of XC of a hyperaemic period of the SCF was demonstrated in ten out of 13 animals. In conclusion, SCF was significantly influenced by changes in CSFP during XC of the thoracic aorta. The findings support the theory that removal of spinal fluid during XC of the thoracic aorta may increase the perfusion pressure to the spinal cord, thereby improving its blood supply.

The use of MRI in the investigation of leg oedema.

Magnetic resonance imaging (MRI) was used in the diagnosis of various conditions giving rise to leg oedema, with special attention to the oedema after femoro-distal vascular reconstruction for obliterative atherosclerosis (n = 14). Patients with deep venous thrombosis (n = 6), chronic lymphoedema (n = 6) and closed muscular compartment syndrome (n = 2) were also investigated. Leg volume increase was measured according to the formula of a truncated cone. Interstitial fluid hydrostatic pressure (Pif) was recorded with the wick-in-needle technique. Spin echo series with 10 mm transverse slices were obtained with MRI. Following vascular reconstructions, leg volume increased 26% on the operated side. In the operated leg, no gradient in Pif was found between the posterior muscular compartment and the subcutaneous tissue. However, there was a significantly higher Pif in the subcutaneous tissue compared to the anterior muscular compartment (p less than 0.05). In the operated group, MRI revealed oedema around the entire circumference of the leg, mainly restricted to the subcutaneous tissue. In contrast, oedema of the leg muscles, particularly in the posterior compartments, was typical for patients having deep venous thrombosis. The group with chronic lymphoedema showed circumferential subcutaneous oedema alone or in combination with a fibrotic honeycomb pattern. Oedema of the affected muscular compartment was easily observed in patients who had a closed compartment syndrome. In conclusion, the use of MRI is promising in the investigation of conditions giving rise to leg oedema. It is likely that the formation of post-reconstructive oedema is taking place in the subcutaneous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in intracranial volume following cross-clamping of the descending thoracic aorta in pigs--an experimental study using MRI.

OBJECTIVES: To determine whether alterations in intracranial volume occurred following cross-clamping of the descending thoracic aorta in pigs. DESIGN AND SETTING: Laboratory animal study. MATERIALS: Eight pigs undergoing cross-clamping of the descending thoracic aorta for 30 min. CHIEF OUTCOME MEASURES: A Philips Gyroscan T5-II Release 3 (0.5 T) was used to obtain intracranial images before cross-clamping, during cross-clamping and after declamping. The ventricular volume was measured on Spin Echo T1-weighted images. The signal intensity of the cerebral tissue was measured on Spin Echo T2-weighted images. Increased signal intensity of the cerebral tissue relative to an external reference was used as an indicator of cerebral oedema. MAIN RESULTS: The ventricular volume decreased to 89% (p < 0.01) of the baseline value after 5 min of cross-clamping. At 5 min after declamping the ventricular volume decreased further to 71% (p < 0.01). At 25 min after declamping the ventricular volume had returned to the baseline value. The signal intensity of the cerebral tissue did not differ from baseline values following aortic cross-clamping. CONCLUSIONS: In this study, ventricular volume decreased following cross-clamping of the descending thoracic aorta. Since no cerebral oedema was observed, the decrease of ventricular volume was most likely due to increased intracranial blood volume.

Shunting of the coeliac and superior mesenteric arteries during thoracoabdominal aneurysm repair.

OBJECTIVES: To describe our experience with shunting of the coeliac and superior mesenteric arteries during thoracoabdominal aneurysm repair. DESIGN: Retrospective study. MATERIAL: Eight patients undergoing resection and graft replacement of Crawford type III (5) and type IV (3) thoracoabdominal aortic aneurysms were included in this series. One patient had rupture, four were symptomatic and three were operated on electively. METHODS: A vascular graft with a sidearm was applied for the reconstructions. A T-shunt was connected to the sidearm. Following completion of the proximal anastomosis the shunt was inserted into the coeliac and superior mesenteric arteries. The anastomoses to these arteries and the renal arteries were then completed. Finally the distal anastomosis was performed. RESULTS: There was no early mortality (30 days). One patient had postoperative paraparesis, but recovered quite well. Reoperation became necessary due to sigmoid necrosis in one patient and due to haemorrhage in another. During the follow-up period four patients died but the other patients are alive between 3 and 8 years after surgery. CONCLUSION: The application of shunting of the superior mesenteric and coeliac arteries during thoracoabdominal aortic surgery is feasible and the results have been acceptable. Further investigation of the optimal blood flow needed to avoid intestinal ischaemia in a larger series of patients is desirable.

Cerebral haemodynamics during thoracic- and thoracoabdominal aortic aneurysm repair.

OBJECTIVE: To investigate cerebral haemodynamics during operations for thoracic and thoracoabdominal aortic aneurysms. DESIGN: Prospective clinical study. MATERIAL: 10 patients operated on consecutively with resection for thoracic (5) or thoracoabdominal aortic (5) aneurysms. METHODS: Blood flow velocity of the middle cerebral artery was measured through a temporal approach using a TC Doppler with a 2 MHz probe. Recordings were made during induction of anaesthesia and performed continuously before, during and after cross-clamping of the aorta. RESULTS: Following 10 min. of aortic cross-clamping blood flow velocity of the middle cerebral artery increased from 44 to 55 cm/s (p < 0.01). A further increase to 69 cm/s (p < 0.01) was observed 5 min after declamping. The pulsatility index averaged 0.74 increasing to 1.21 (p < 0.05) at clamping and 0.87 (p < 0.05) after declamping. CONCLUSION: There was an increased blood flow velocity of the middle cerebral artery during cross-clamping of the descending thoracic aorta in patients operated on for thoracic and thoracoabdominal aortic aneurysms. This increase in cerebral blood flow and blood volume could explain the acute increase in cerebrospinal fluid pressure observed during cross-clamping of the thoracic aorta.

The importance of transesophageal echocardiography during surgery of the thoracic aorta.

OBJECTIVES: To assess left ventricular dimensions and cardiac output during thoracic and thoracoabdominal aortic aneurysm repair. MATERIAL AND METHODS: Nine patients undergoing thoracic and thoracoabdominal aneurysm repair using direct cross-clamping without shunt or by-pass were studied prospectively. Prior to, during cross-clamping (XC) and after declamping left ventricular cross-sectional areas were monitored with transesophageal echocardiography. A pulmonary artery catheter was used for measurements of cardiac output with the thermodilution technique. RESULTS: Cardiac output increased 43% from baseline during XC (p < 0.01) and was still 55% above baseline at declamping (p < 0.05). Left ventricular end-systolic inner area was reduced 32% during XC (p < 0.01). Pulmonary artery pressures and central venous pressure increased during declamping (p < 0.05). Heart rate increased 38% from 66 beats/ min to 92 beats/min (p < 0.01) and was still 30% elevated at declamping (p < 0.01). CONCLUSION: During thoracic aortic XC, cardiac output is increased and left ventricular end-systolic dimension is reduced. TEE is a valuable supplement to pressure measurements for the evaluation of cardiac function during surgery of the thoracic aorta.

[Endovascular treatment of thoracic aortic aneurysm]. / Endovaskulaer behandling av torakale aortaaneurismer.

Two patients with aneurysms of the descending thoracic aorta were treated by endovascular technique. One of the patients was also treated for an infrarenal aortic aneurysm by open surgery during the same procedure. The other patient had chest pain, probably caused by an impending rupture. The procedures were performed using fluoroscopy by a C-arm. The thoracic aneurysms were replaced by an implant made of polyester where Z-stents had been applied on the inside. The prosthesis was mounted on a pusher and advanced through an introducer. When a proper position was obtained, the introducer was withdrawn, and the prosthesis was deployed immediately below the left subclavian artery. Endovascular treatment seems to represent a less traumatic procedure than open surgery. Both operations were uncomplicated and both patients were followed up for more than six months. No complications were observed. A longer follow-up period is necessary to evaluate this treatment fully.

A strategy for treatment of type III and IV thoracoabdominal aortic aneurysm.

The aim of this study was to describe the results of resection and graft replacement for type III and IV thoracoabdominal aortic aneurysm repair. In this retrospective study, 27 patients underwent resection and graft replacement for type III (10) or type IV (17) thoracoabdominal aortic aneurysms. Nine patients had rupture, 12 were symptomatic, and 6 were operated on electively. The "clamp-and-sew" technique was applied in six cases. In 12 patients with type IV aneurysm the proximal part of the vascular graft was beveled, including the orifices of the celiac, superior mesenteric, and one or both renal arteries in the proximal anastomosis. Finally, eight patients underwent surgical application of a shunt for perfusion of the celiac and superior mesenteric arteries. One patient was treated with a combination of open and endovascular surgery. There were four early deaths (14.8%), all following operations for rupture, which represents a 45% mortality rate in this subgroup of patients. Two patients with type III aneurysm had postoperative paraparesis. One was symptomatic whereas the other was operated on electively. Excluding the patients with rupture, the accumulated 5-year survival rate was 65%. These results indicate that direct cross-clamping of the aorta gives limited time for performing the necessary anastomoses without inducing mesenteric ischemia. Inclusion of the orifices of the visceral arteries in the upper anastomosis is a feasible method during surgery for type IV aneurysms. Finally, shunting of the celiac and the superior mesenteric arteries seems to be useful, especially during surgery for type III aneurysms.

Cerebral haemodynamics during proximal aortic cross-clamping.

This study was carried out to examine cerebral blood flow, including the microcirculation and intracranial pressure during cross-clamping (XC) of the thoracic aorta in pigs. Blood flow in the internal carotid artery was measured by electromagnetic flowmetry. Cerebral microcirculation was studied by the laser Doppler technique, and intracranial pressure measured by applying a fibre optic pressure monitoring catheter in the same craniotomy. Maximal and mean blood flow velocity of the middle cerebral artery was recorded using a transcranial Doppler and cardiac output measured by thermodilution. The thoracic aorta was cross-clamped distal to the left subclavian artery for 30 min. During aortic XC the internal carotid artery blood flow increased 191% (p less than 0.05). Simultaneously mean and maximal blood flow velocity of the middle cerebral artery both increased 125% (p less than 0.01). Intracranial pressure increased 163% (p less than 0.05), and there was an increase in cerebral flux of 23% (p less than 0.05). Within the first minutes following the release of XC, all values decreased to preocclusive values. In conclusion, we observed a significant increase in cerebral blood flow during XC of the thoracic aorta. This is in accordance with the finding of a simultaneous increase in cardiac output. These haemodynamic changes support the theory that an increased blood flow via the proximal feeding system to the anterior spinal artery might be important in avoiding neurological sequelae following proximal aortic XC.

Spinal cord metabolism during thoracic aortic cross-clamping in pigs with special reference to the effect of allopurinol.

OBJECTIVE: investigate the metabolic response of the spinal cord and the effect of allopurinol following cross clamping of the descending thoracic aorta in a porcine model. DESIGN: experimental animal study. MATERIALS: twelve domestic swine. Six pigs were pre-treated with allopurinol, while six pigs served as controls. METHODS: measurement of extracellular concentrations of glucose, pyruvate, lactate, glycerol and glutamate using microdialysis in the lumbar spinal cord. Measurement of lumbar spinal blood flow using laser Doppler technique. RESULTS: for all animals there was a significant decrease in concentrations of glucose and pyruvate together with a significant increase in the lactate-pyruvate ratio during aortic cross clamping. There was also a significant increase in glycerol concentrations 60 min after cross clamping, and a significant decrease in glutamate concentrations after 50 min. No differences in concentrations of glucose, pyruvate, lactate and glutamate or the glutamate-pyruvate ratio were observed between animals used as controls and those treated with allopurinol. The laser Doppler flux decreased to 40% of pre cross-clamp level, returning to normal values at declamping. CONCLUSION: the changes in energy-related metabolites reflect a considerable ischaemia in the spinal cord tissue but there was no convincing effect of allopurinol on the lumbar spinal cord metabolism during thoracic aortic cross clamping in this model.

Cerebrospinal fluid production during proximal aortic cross-clamping.

During cross-clamping (XC) of the thoracic aorta, the cerebrospinal fluid pressure (CSFP) increases. The mechanism of the increased CSFP is unknown but increased cerebrospinal fluid (CSF) production has been suggested as one explanation. The aim of this study was to investigate whether the CSF production rate was influenced by proximal XC of the thoracic aorta in an experimental model. Using the ventriculocisternal perfusion method including [14C] inulin, the rate of CSF production was measured before, during and after XC of the thoracic aorta in seven pigs. The CSFP was measured via a catheter in the lateral ventricle and the thoracic aorta was cross-clamped just distal to the left subclavian artery for 30 minutes. Following cross-clamping the CSFP increased from 5 mmHg to 11 mmHg (p < 0.001) and remained elevated during XC. In contrast the CSF production rate was 0.09 ml/min prior to XC and was not significantly altered following XC. In conclusion this experimental study indicates that increased CSF production is not responsible for the increase in CSFP during XC.

Effect of sodium nitroprusside on cardiac output during cross-clamping of the descending thoracic aorta in pigs.

Sodium nitroprusside (SNP) is used to control proximal hypertension during cross-clamping of the descending thoracic aorta (XC). To assess the haemodynamic effects of SNP on cardiac output (CO) during XC, 21 pigs were anaesthetized with ketamine and fentanyl. In the control group (n = 11), no vasodilating therapy was given. In the investigation group (SNP group), 2 animals died during the surgical preparation and were excluded, leaving 8 animals in the group (n = 8). In these animals, SNP was infused in order to keep the mean arterial pressure (MAP) at about 100 mm Hg during cross-clamping. In both groups, aorta was cross-clamped for 30 min, and cardiac output (CO) was measured by the thermodilution technique. Following cross-clamping, CO increased 107% in the control group and 96% in the SNP group. There was an increase in heart rate (HR) of 77% in the control group and of 110% in the SNP group, and a reduction in systemic vascular resistance of 41% in the SNP group. Stroke volume (SV) was unchanged in both groups. MAP increased 83% in the control-group. No differences were observed between the two groups regarding central venous pressure or pulmonary artery pressure. Four animals in the SNP group died 5-10 min after release of the aortic clamp. In conclusion, we found equal increase in CO in both groups. The increase in CO was related predominantly to increased HR, whereas SV was largely unaltered. Vasodilation with SNP increased the mortality following clamp removal in this experimental model.