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Biomedical subjects

A Heino

Publications and source records attributed to A Heino.

At least 19 recordsLinked to original sources
PubMed2002

Effects of fluid and dobutamine treatment on renal function during partial superior mesenteric artery occlusion and reperfusion.

OBJECTIVE: We compared the effects of dobutamine, fluid resuscitation and their combination on renal function during experimental intestinal ischaemia and reperfusion. MATERIALS AND METHODS: Superior mesenteric artery (SMA) blood flow was reduced to 30% from the baseline for 120 minutes in 24 anaesthetized pigs (ischaemic group); 24 pigs (sham group) served as non-ischaemic controls. The animals were further assigned into four treatment arms. In the control arms, the animals were given only basic fluid therapy. In the fluid therapy arms, pulmonary capillary wedge pressure (PCWP) was maintained at 10 mmHg with intravenous fluids. In the dobutamine treatment arm, dobutamine hydrochloride was infused at a dose of 10 microg/min/kg. In the combined dobutamine-fluid therapy arms, dobutamine at 10 microg/min/kg was given and PCWP was maintained at 10 mmHg with fluids. At 120 minutes, the occluder was released in all study groups and the animals were followed for an additional 60 minutes. Renal function was evaluated by means of serum and urine creatinine. urine volume and creatinine clearance. Systemic and regional haemodynamics as well as intramucosal pH, intramucosal-arterial pCO2 gradient, and portal venous-arterial lactate gradient were measured. RESULTS: In the ischaemic groups, diuresis increased and serum and urine creatinine decreased significantly in fluid (p < 0.01, p < 0.01 and p < 0.05, respectively) and dobutamine-fluid (p < 0.01, p < 0.001 and p < 0.001, respectively) treated groups during SMA ischaemia. After SMA reperfusion, diuresis decreased in control group (p < 0.05) and in animals treated with dobutamine alone (p < 0.01). In addition, urine creatinine increased in dobutamine treated group (p < 0.05), and creatinine clearance decreased in control group (p < 0.01). Renal function and diuresis during the SMA occlusion and reperfusion did not differ between ischaemic and sham groups. All fluid treated groups had lower serum creatinine during SMA occlusion than control groups (p < 0.001). CONCLUSIONS: Intestinal ischaemia caused by partial SMA occlusion did not influence renal function. On the contrary, SMA reperfusion resulted in a significant impairment of renal function both in ischaemic and sham operated animals. The impairment was most obvious in control groups and in animals treated with dobutamine alone.

Animals↗
PubMed2001

Two-year follow-up results of a prospective randomized trial comparing hybrid laser prostatectomy with TURP in the treatment of big benign prostates.

OBJECTIVE: We compared conventional transurethral electroresection of the prostate (TURP) and hybrid laser treatment in patients with symptomatic bladder outflow obstruction caused by a benign prostate bigger than 40 ml. MATERIAL AND METHODS: Forty-six patients with symptomatic urodynamically confirmed outflow obstruction caused by benign prostate hyperplasia bigger than 40 ml were accepted to the prospective trial and were randomized to receive hybrid laser treatment or TURP. The hybrid laser technique involved initial non-contact Nd:YAG coagulation followed by contact Nd:YAG vaporization to open the prostatic urethra. Patients were re-assessed after 3, 6, 12 and 24 months. RESULTS: Of the 46 patients, 37 (80%) were available at the 24-month follow-up. The re-operation rate was 14.3% in the hybrid laser group and 8.3% in the TURP group. The decrease in DanPSS-1 symptom score from baseline at 24 months was 51.0% in the hybrid laser group (p<0.01) and 80.0% in the TURP group (p<0.001), with no statistically significant differences between the groups. Early improvement in objective urinary parameters of peak urinary flow rate and residual urinary volume showed deterioration in hybrid laser group during longer follow-up, whereas in TURP group the improvement of these variables was sustained. Comparison between groups showed TURP to be superior in peak urinary flow rate (p < 0.001) and residual urinary volume (p < 0.01) at the 24-month follow-up visit. CONCLUSIONS: Both hybrid laser treatment and TURP give good symptomatic relief lasting at least 2 years in the treatment of big obstructing prostates, but hybrid laser treatment is associated with a higher re-operation rate because of inadequate initial prostate tissue removal and with inferior outcome in objective urinary parameters compared with TURP.

Aged↗
PubMed2001

Effects of systemic arterial hypoperfusion on splanchnic hemodynamics and hepatic arterial buffer response in pigs.

The hepatic arterial buffer response (HABR) tends to maintain liver blood flow under conditions of low mesenteric perfusion. We hypothesized that systemic hypoperfusion impairs the HABR. In 12 pigs, aortic blood flow was reduced by cardiac tamponade to 50 ml. kg(-1). min(-1) for 1 h (short-term tamponade) and further to 30 ml. kg(-1). min(-1) for another hour (prolonged tamponade). Twelve pigs without tamponade served as controls. Portal venous blood flow decreased from 17 +/- 3 (baseline) to 6 +/- 4 ml. kg(-1). min(-1) (prolonged tamponade; P = 0.012) and did not change in controls, whereas hepatic arterial blood flow decreased from 2 +/- 1 (baseline) to 1 +/- 1 ml. kg(-1). min(-1) (prolonged tamponade; P = 0.050) and increased from 2 +/- 1 to 4 +/- 2 ml. kg(-1). min(-1) in controls (P = 0.002). The change in hepatic arterial conductance (DeltaC(ha)) during acute portal vein occlusion decreased from 0.1 +/- 0.05 (baseline) to 0 +/- 0.01 ml. kg(-1). min(-1). mmHg(-1) (prolonged tamponade; P = 0.043). In controls, DeltaC(ha) did not change. Hepatic lactate extraction decreased, but hepatic release of glutathione S-transferase A did not change during cardiac tamponade. In conclusion, during low systemic perfusion, the HABR is exhausted and hepatic function is impaired without signs of cellular damage.

Animals↗
PubMed2001

MR urography in evaluation of acute flank pain: T2-weighted sequences and gadolinium-enhanced three-dimensional FLASH compared with urography. Fast low-angle shot.

OBJECTIVE: The aim of this study was to compare the usefulness of breath-hold heavily T2-weighted sequences with gadolinium-enhanced three-dimensional fast low-angle shot (3D FLASH) MR urography in the evaluation of patients with acute flank pain. SUBJECTS AND METHODS: Forty consecutive patients with symptoms of acute flank pain underwent MR urography followed immediately by excretory urography. Heavily T2-weighted (combined thin-slice half-Fourier acquisition single-shot turbo spin-echo [HASTE] and thick-slab single-shot turbo spin-echo) and 3D FLASH sequences were evaluated separately and independently by two experienced radiologists for the presence, cause, level, and degree of obstruction. Interobserver agreement was calculated using the kappa statistic. Excretory urography and the final clinical diagnosis were used as reference. RESULTS: Twenty-six patients were found to have unilateral obstruction caused by ureteral stones. Both MR urography methods were excellent for detecting obstruction. In the detection of stones 3D FLASH was superior, with a sensitivity of 96.2% and 100% and specificity of 100% and 100% for observers A and B, respectively, compared with a sensitivity of 57.7% and 53.8% and a specificity of 100% and 100%, respectively, for T2-weighted sequences. The best degree of obstruction was seen with 3D FLASH, and the interobserver agreement was excellent for stone detection (kappa = 0.97). CONCLUSION: T2-weighted sequences alone are not sufficient for examining patients with acute flank pain. However, the combined use of both T2-weighted and 3D FLASH sequences will ensure better confidence in the evaluation of acute suspected renal colic. MR urography can replace conventional excretory urography when the latter is contraindicated or undesirable.

Acute Disease↗
PubMed2000

Effects of dobutamine on splanchnic tissue perfusion during partial superior mesenteric artery occlusion.

OBJECTIVE: To evaluate the effects of dobutamine and fluid treatment on splanchnic hemodynamics and tissue oxygenation during partial superior mesenteric artery occlusion. DESIGN: Prospective, open randomized, full-factorial design. SETTING: University research laboratory. SUBJECTS: Forty-eight female pigs. INTERVENTIONS: In 24 anesthetized pigs (ischemic group), superior mesenteric artery (SMA) blood flow was reduced to 30% from the baseline for 120 mins; 24 pigs (sham group) served as nonischemic controls. The animals were further assigned into four treatment arms. In the control arm, the animals were administered only basic fluid therapy. In the fluid therapy arm, pulmonary artery occlusion pressure was maintained at 10 mm Hg with fluids. In the dobutamine treatment arm, dobutamine hydrochloride was infused at a dose of 10 microg/min/kg. In the combined dobutamine-fluid therapy arm, dobutamine at 10 microg/min/kg was administered and pulmonary artery occlusion pressure was maintained at 10 mm Hg with fluids. MEASUREMENTS AND MAIN RESULTS: Systemic and regional hemodynamics and oxygen transport, as well as jejunal intramucosal pH, intramucosal-arterial PCO2 gradient, and portal venous-arterial lactate gradient were measured. Ischemia did not modify the effects of fluids or dobutamine on systemic hemodynamics and oxygen transport. Dobutamine-treated animals had a higher cardiac index compared with control animals (218 +/- 22 vs. 135 +/- 13 mL/min/kg; p = .012), and the effect was enhanced when dobutamine was combined with fluid treatment (365 +/- 23 mL/ min/kg; p = .019). Fluid treatment alone did not influence cardiac index, whereas it increased SMA blood flow compared with control groups (15 +/- 2 vs. 12 +/- 2 mL/min/kg; p = .023). Dobutamine also decreased the proportion of SMA blood flow of cardiac output compared with control groups (6 +/- 1 vs. 9% +/- 1%; p = .024). Other treatments had no effect on SMA blood flow. Ischemia increased intramucosal-arterial Pco2 gradient to 54.8 +/- 10.7 torr (7.31 +/- 1.43 kPa) (p = .002 vs. sham control) and decreased intramucosal pH to 7.13 +/- 0.06 (p = .028 vs. sham control). In the ischemic animals, dobutamine without fluid therapy reduced intramucosal pH further to 7.00 +/- 0.09 (p = .023 vs. ischemic control) and increased portal venous-arterial lactate gradient (p = .033). CONCLUSIONS: Dobutamine alone worsened splanchnic tissue perfusion during partial superior mesenteric artery occlusion. As compared with fluid treatment alone, the combination of fluid and dobutamine therapy did not improve tissue perfusion.

Animals↗
PubMed2000

Prevention of systemic hyperlactatemia during splanchnic ischemia.

Arterial blood lactate increases as a result of poor tissue perfusion. In splanchnic hypoperfusion, increased hepatic lactate uptake may delay increases in arterial blood lactate. We hypothesized that during isolated reduction of mesenteric blood flow, maintaining systemic blood volume and flow by fluid resuscitation may prevent systemic hyperlactatemia and therefore mask splanchnic ischemia. In a randomized study, 7 pigs were subjected to 4 h of splanchnic hypoperfusion by reducing the superior mesenteric artery blood flow to 4 +/- 0.8 mL/kg min [mean +/- standard deviation (SD)]. Seven pigs served as controls. Fluid was administered in order to keep the pulmonary artery occlusion pressure at 5 to 8 mm Hg. Cardiac output, portal vein, superior mesenteric, and hepatic arterial blood flow were measured every 30 min. Arterial, mixed venous, hepatic, portal, and mesenteric venous blood lactate, and jejunal mucosal pCO2 were measured at baseline and thereafter at 30-min intervals. The initial decrease in portal venous blood flow in the ischemic animals was subsequently counterbalanced by increasing hepatic arterial blood flow from 2 +/- 1 mL x kg(-1) x min(-1) at baseline to 11 +/- 4 mL x kg(-1) x min(-1) [after 4 h of ischemia; mean +/- standard deviation (SD), P = 0.02]. Jejunal mucosal- and mesenteric vein-arterial pCO2 gradients increased in the ischemic group from 11 +/- 8 mm Hg to 73 +/- 5 mm Hg (P = 0.02), and from 10 +/- 4 mm Hg to 44 +/- 8 mm Hg, respectively (P = 0.02). Mesenteric and portal venous lactate increased in the ischemic animals from 1.1 +/- 0.3 mmol/L to 4.2 +/- 1.0 mmol/L (P = 0.02), and from 1.0 +/- 0.2 mmol/L to 1.6 +/- 0.3 mmol/L, respectively (P = 0,03). While mesenteric lactate production and hepatic lactate uptake increased in parallel in the ischemic animals from 5 +/- 6 micromol x kg(-1) x min(-1) to 14 +/- 5 micromol x kg(-1) x min(-1) (P = 0.04), and from 14 +/- 7 micromol x kg(-1) x min(-1) to 24 +/- 6 micromol x kg(-1) x min(-1), respectively (P = 0.02), hepatic venous and arterial lactate, and apparent splanchnic lactate uptake and extraction did not change. We conclude that the hepatic lactate uptake increases in response to hepatic lactate influx. Systemic hyperlactatemia and increased hepatic venous lactate concentrations are late consequences of mesenteric hypoperfusion if hypovolemia is prevented. The net exchange of lactate across the splanchnic region does not reflect hepato-portal lactate kinetics in this animal model of intestinal hypoperfusion.

Animals↗
PubMed2000

The morphological, in situ effects of a self-reinforced bioabsorbable polylactide (SR-PLA 96) ureteric stent; an experimental study.

PURPOSE: The present study was done to evaluate the biocompatibility of a new biodegradable double helical spiral self-reinforced poly-L, D-lactide copolymer (L/D ratio 96/4, SR-PLA96) ureteric stent. MATERIALS AND METHODS: In sixteen dogs, the right ureter was cut transversally, sutured and stented with a 50 mm. long SR-PLA 96 stent. In eight dogs, left ureter was similarly operated and stented with a double-J pigtail stent (C-Flex, Cook Urological Inc.), while eight remaining ureters served as plain controls. Urine was analyzed for signs of infection. The dogs were terminated at 6, 12 and 24 weeks postoperatively and the ureters dissected to find persistent SR-PLA 96 particles or local ureteric changes. Histologic samples were taken at three levels of dissected ureters in contact with the stent. RESULTS: C-Flex and SR-PLA 96 materials were well tolerated. Both of these induced only minimal ureteral wall edema, epithelial hyperplasia, epithelial destruction and inflammatory cell reaction. In SR-PLA 96 stented ureters the tissue reaction subsided after the degradation of the device. CONCLUSIONS: SR-PLA 96 spiral stent is regarded highly compatible and SR-PLA 96 might be a suitable material for a partial ureteric stent. Biodegradation of a SR-PLA 96 stent makes stent removal unnecessary.

Absorbable Implants↗
PubMed1999

Application of a self-reinforced polyglycolic acid (SR-PGA) membrane to the closure of an abdominal fascial defect in rats.

The suitability of a polyglycolic acid (PGA) membrane to fascial closure was tested in 40 rats. To induce collagen synthesis, a fascial strip from the vastus lateralis muscle was applied to the peritoneal side of the PGA membrane. A midline laparotomy was performed, and the incision was covered with the membrane fixed at the edges. The animals were sacrificed at 3, 6, 12, and 28 weeks, at which time macroscopical, histological, and electron microscopical findings, as well as the results of breaking force tests were evaluated. Fascial augmentation had no effect on the results. Ventral hernias were observed in 37.5% of the cases, half of which were observed after 6 weeks postoperatively. In one case, intestinal adhesions to the membrane were found. Inflammatory reaction during the follow-up was moderate and lasted up to 12 weeks. Breaking force decreased up to 6 weeks, after which it slightly increased without reaching the breaking force level of the control animals.

Abdominal Injuries↗
PubMed1999

Hybrid laser treatment compared with transurethral resection of the prostate for symptomatic bladder outlet obstruction caused by a large benign prostate: a prospective, randomized trial with a 6-month follow-up.

OBJECTIVE: To compare the efficacy and safety of hybrid laser treatment, i.e. the combination of visual Nd-YAG laser ablation of prostate and contact Nd-YAG laser vaporization of prostate, with transurethral resection of the prostate (TURP) in the treatment of patients with symptomatic bladder outlet obstruction secondary to a benign high-volume prostate. PATIENTS AND METHODS: Forty-five symptomatic patients with hyperplastic prostates of >40 mL were randomized to undergo either hybrid laser treatment (21) or TURP (24). All patients were evaluated before and after treatment with a complex urodynamic assessment, and were accepted into the study only if they had infravesical obstruction in the pressure-flow study. In the hybrid method, Nd-YAG laser energy was first delivered by an 'adenoma-dependent' approach to all areas of the obstructing lateral lobe tissue through a side-firing gold-alloy tip fibre at 40 W for 90 s of 'burn'. The prostatic urethra was then opened and the median lobe vaporized using the a contact probe at 40 W. Patients were re-evaluated 3 and 6 months after treatment. RESULTS: Both treatments proved to be safe, and improved the subjective and objective outcome measures at 3 and 6 months compared with baseline values. After 3 months, there was a greater improvement in the TURP group in peak urinary flow rate (Qmax; P<0.01), mean urinary flow rate (Qave; P<0.01) and postvoid residual urine volume (P<0.05) than in the hybrid laser group. After 6 months, there was a greater improvement in the TURP group in detrusor pressure at Qmax (P<0.01), Qave (P<0.05) and prostate size (P<0.001) than in the hybrid laser group. In the pressure-flow study at 6 months, a higher proportion of patients (seven of 19) were still obstructed in the hybrid laser group than in TURP group (two of 21; P<0.05). TURP caused more intraoperative blood loss (P<0.001) and postoperative problems associated with bleeding; 38% of hybrid laser patients were discharged with a suprapubic catheter, whereas all TURP patients could urinate at discharge (P<0.01). The duration of bladder drainage was longer after hybrid laser treatment (P<0.001). CONCLUSION: The hybrid laser method was a safe but less effective treatment than TURP for benign prostatic enlargement in patients with prostates of >40 mL.

Aged↗
PubMed1999

Contact laser prostatectomy compared to TURP in prostatic hyperplasia smaller than 40 ml. Six-month follow-up with complex urodynamic assessment.

OBJECTIVE: To compare the efficacy and safety of contact laser vaporization (CLV) of the prostate and transurethral resection of the prostate (TURP). MATERIAL AND METHODS: Fifty patients with symptomatic prostatic hyperplasia with prostate volumes less than 40 ml were randomized to CLV or TURP treatment. All patients had infravesical obstruction confirmed preoperatively by pressure-flow studies. RESULTS: CLV lasted longer (51 +/- 13 min versus 34 +/- 12 min; p < 0.001), caused less bleeding (57 +/- 49 ml versus 175 +/- 133 ml; p < 0.001) and required longer bladder drainage time (4.3 +/- 6.1 versus 1.7 +/- 0.8 days; p < 0.01) than TURP. At 6-month follow-up, both treatments had improved objective urinary parameters and effectively reduced subjective symptoms. There were no significant differences between the study groups in symptoms scores (DanPSS-1), peak urinary flow rates (Qmax) and post-void residuals (PVR). Six months after treatment the detrusor pressure at peak urinary flow rate (PdetQmax) was 38.3 +/- 9.7 cm H2O in CLV patients and 31.3 +/- 9.9 cm H2O in TURP patients (NS). CLV treatment caused less retrograde ejaculation than TURP (1/16 potent CLV men versus 13/16 potent TURP men; p < 0.001). CONCLUSIONS: Contact laser prostatectomy proved to be a safe procedure which improved subjective and objective urinary parameters during 6-month follow-up as effectively as TURP in the treatment of symptomatic infravesical obstruction caused by minimal or moderate benign prostate enlargement.

Aged↗
PubMed1999

New bioabsorbable polylactide ureteral stent in the treatment of ureteral lesions: an experimental study.

OBJECTIVE: To evaluate the suitability of a new biodegradable double-helical spiral self-reinforced poly-L,D-lactide copolymer (SR-PLA 96; L/D ratio 96/4) stent as a device for ureteral stenting in respect to changes in kidney function during the biodegradation process. MATERIALS AND METHODS: Sixteen dogs were used as experimental animals and were subdivided into two groups of eight. In Group A, both ureters were cut transversally, sutured, and stented. The right ureter was stented using an SR-PLA 96 stent, whereas a double-J C-Flex stent was used on the left side. Cystotomy was performed at 6 weeks to remove the double-J stents. In Group B, the right ureter of each dog was cut and stented in similar manner using an SR-PLA 96 stent, whereas the left ureters served as untreated controls, and cystotomy was not performed. Serum creatinine and nitrogen values were measured, urine was analyzed for signs of infection, and renal function was evaluated by urography and renography examinations preoperatively and at 6, 12, and 24 weeks postoperatively, at which time points, the dogs were euthanized and the ureters dissected to find persistent SR-PLA 96 particles and macroscopic local changes. There were no urinary tract infections found during the study. RESULTS: In the SR-PLA 96-stented ureters, obstructive hydronephrosis and stricture formation were observed in two cases (11%), with distal displacement of the SR-PLA 96 stent in another case (5.5%). In two additional renal units, a temporary prolongation in the kidney washout time was observed at 6-week renogram examinations. In the C-Flex-stented ureters, temporary changes in renography studies were observed in three cases (37.5%) at 6 weeks. Kidney washout times were protracted at 6 weeks in the pigtail-stented ureters in Group A as a sign of a pressure rise in the renal pelvis secondary to the direct connection between the renal pelvis and bladder, whereas pressure remained normal in SR-PLA 96-stented ureters. In Group B, renal function remained normal after ureteral repair in SR-PLA 96-stented ureters compared with the controls. CONCLUSIONS: The double-helical apical stent design offers some advantages over a double-J design. The risk of pressure-induced kidney damage is lowered, because there is no direct connection between the bladder and renal pelvis, and the risk of upper urinary tract infections is reduced. The biodegradation of the device necessitates the removal of the stent. These preliminary results suggest that a biodegradable SR-PLA 96 stent with more effective expansion capacity can be used for stenting after a ureteral repair.

Absorbable Implants↗
PubMed1999

BTA test is superior to voided urine cytology in detecting malignant bladder tumours.

BACKGROUND AND AIMS: In a prospective study, Bard BTA (bladder tumour antigen) test was compared to voided urine cytology (VUC) in detecting primary and recurrent bladder cancer (BC). MATERIALS AND METHODS: 407 control cystoscopies, BTA test and VUC were performed on 150 patients, of which 96 (23.6%) recurrent tumours were found, and 43 patients with a new BC were noticed. RESULTS: BTA test was superior to VUC in detecting superficial Ta (23% vs. 3%, p < 0.001) and grade 1 (16% vs. 0%, p < 0.001) as well as grade 2 (35% vs. 11%, p < 0.01) tumours. In Tis and T2-T4 tumours as well as in grade 3 tumours both tests performed similarly. The sensitivity of BTA test compared to VUC in detecting recurrent tumours was higher (24 % vs. 9%, p < 0.01), but VUC had more specificity than BTA test (99% vs. 80%, p < 0.001). CONCLUSIONS: BTA test was superior to VUC in detecting BC and its recurrence. The simultaneous use of the BTA test and VUC did not add any information in detecting tumour growth in the bladder as compared to the BTA test alone.

Aged↗
PubMed1998

Systemic and regional pCO2 gradients as markers of intestinal ischaemia.

OBJECTIVE: We evaluated the response of mixed venous-arterial carbon dioxide (pCO2) to severe intestinal ischaemia produced by gradual occlusion of the superior mesenteric artery (SMA). DESIGN: Prospective, controlled, experimental study. SETTING: Animal research laboratory. SUBJECTS: Twelve domestic pigs. INTERVENTIONS: SMA blood flow was reduced by 40%, 70% and 100% from the baseline at 60-min intervals. MEASUREMENTS AND MAIN RESULTS: Haemodynamics were monitored continuously and blood gas values were determined at 30-min intervals. During the SMA occlusion we observed the development of intramucosal acidosis, increased splanchnic oxygen extraction and an increased portal venous-arterial lactate gradient indicative of splanchnic hypoperfusion and intestinal ischaemia. Intramucosal-arterial (p < 0.001), intramucosal-portal venous (p < 0.01) and portal venousarterial (p < 0.01) pCO2 gradients increased during the SMA occlusion, whereas the mixed venous-arterial pCO2 gradient remained unchanged. The mixed venous-arterial pCO2 gradient did not correlate with the intramucosal-arterial pCO2 gradient (r = 0.13), portal venous-arterial lactate gradient (r = 0.10) or splanchnic oxygen extraction (r = 0.14). The portal venous-arterial pCO2 gradient correlated with the portal venous-arterial lactate gradient (r = 0.75, p < 0.001) and splanchnic oxygen extraction (r = 0.79, p < 0.001), but not with the intramucosal-arterial pCO2 gradient (r = 0.35). CONCLUSION: Despite clear evidence of severe splanchnic hypoperfusion, as shown by regional hypercarbia and lactate production, the mixed venous-arterial pCO2 gradient did not reflect splanchnic hypoperfusion.

Acidosis, Lactic↗
PubMed1998

Ultrasonography of the ureter after surgical trauma.

BACKGROUND: The purpose of the study was to discover whether ultrasonography can be used in diagnosing ureteral complications during surgery. METHODS: The study consisted of an animal experiment with five pigs, that underwent laparotomy. The right ureter was electrocauterized and transsected, and the left ureter was ligated. The type and frequency of peristaltic waves and the diameter of the ureter were recorded by perioperative ultrasonography. Four patients with ureteral trauma during gynecologic surgery were also examined. RESULTS: In the animal study six out of nine ureters dilated after the procedure. In seven ureters the contraction segment became smaller, and the lumen did not close properly during the peristaltic wave. The frequency of peristalsis diminished in all cases after ligation. Human ureters showed similar changes when examined 1.5-48 h after surgical trauma. CONCLUSIONS: Perioperative ultrasonography has great diagnostic potential as a method for noninvasive evaluation of ureteral conditions during both laparoscopy and laparotomy.

Animals↗
PubMed1997

Systemic and regional effects of experimental gradual splanchnic ischemia.

PURPOSE: We evaluated the effects of gradual intestinal ischemia on systemic and regional haemodynamics and oxygen transport. MATERIALS AND METHODS: Superior mesenteric artery (SMA) blood flow was decreased by 40%, 70%, and 100% for 60-minute periods and thereafter released in 12 pigs. Hemodynamic changes were monitored continuously, and the intestinal perfusion was evaluated by changes in portal vein-arterial lactate gradient, intramucosal pH, tonometric Pco2, tonometric-portal vein Pco2 gradient, and regional oxygen extraction. RESULTS: Local signs of intestinal hypoperfusion developed during the SMA occlusion. Intramucosal pH and portal vein pH decreased from 7.18 +/- 0.04 to 6.81 +/- 0.04 (P < .01) and from 7.36 +/- 0.01 to 7.25 +/- 0.03 (P < .05), respectively. Intramucosal Pco2 and tonometric-portal vein Pco2 gradient increased from 12.4 +/- 1.3 to 21.2 +/- 1.8 kPa (P < .01) and from 6.0 +/ 1.3 to 14.0 +/- 1.9 kPa (P < .05), respectively. Portal vein-arterial lactate gradient and splanchnic oxygen extraction increased from 0.02 +/- 0.07 to 2.32 +/- 0.47 mmol/L (P < .01) and from 0.44 +/- 0.03 to 0.60 +/- 0.03 (P < .05), respectively. Systemic changes observed during the SMA occlusion were reduction of cardiac index (161 +/- 12 to 114 +/- 8 mL/min/kg, P < .01) and pulmonary capillary wedge pressure (4 +/- 1 to 3 +/- 1 mm Hg) and increase in heart rate (124 +/- 5 to 173 +/- 11 beats/ min, P < .01) and mean arterial pressure (79 +/- 3 to 104 +/- 5 mm Hg, P > .01). Systemic oxygen extraction increased (P > .05), arterial pH increased (P < .05), and arterial lactate decreased (P < .01) during the SMA occlusion. Splanchnic ischemia defined as an increase in portal vein-arterial lactate gradient above mean +2 SD of the baseline occurred at 93 +/- 15 minutes corresponding 70% SMA occlusion. CONCLUSION: We conclude that signs of tissue hypoperfusion started to develop at 70% SMA occlusion and that regional tissue hypoperfusion in the splanchnic region may develop without any systemic signs of oxygen supply/demand mismatch.

Hemodynamics↗
PubMed1996

Characteristics of poly(L-)lactic acid suture applied to fascial closure in rats.

A new poly(L-)lactic acid (PLLA) thread was tested by applying it in fascial closures of male Wistar rats. The tissue reactions around the thread and in the fascial union, and the changes on the surface and the mechanical properties of the thread were evaluated at 1, 3, 6, 12, 28, and 52 weeks following surgery. Histologically, the extension of the general inflammatory reaction and the number of the different cell types did not markedly change during the 52-week follow-up period. The surface of the thread was intact up to 28 weeks when examined with the scanning electron microscope. At 52 weeks no thread was found. The breaking force and the stretching of the incubated PLLA thread was reduced about 20% during the first 2 weeks and it remained constant up to 6 weeks. The in vivo testing of the fascial strips closed with the PLLA thread retained their resistance against the breaking force, nearly comparable to that of the intact control fascial strips. It can be concluded that the PLLA thread is a suitable suture for wounds that require healing time of up to 28 weeks and thus need good support from the suture.

Abdominal Muscles↗
PubMed1996

Choice of time-headway in car-following and the role of time-to-collision information in braking.

Time-headway (THW) during car-following and braking response were studied in a driving simulator from the perspective that behaviour on the manoeuvring level (e.g. choice of THW) may be linked to operational competence of vehicle control (e.g. braking) via a process of adaptation. Time-headway was consistent within drivers and constant over a range of speeds. Since time-headway represents the time available to the driver to reach the same level of deceleration as the lead vehicle in case it brakes, it was studied whether choice of time-headway was related to skills underlying braking performance. The initiation and control of braking were both affected by time-to-collision (TTC) at the moment the lead vehicle started to brake. This strongly supported the idea that time-to-collision information is used for judging the moment to start braking and in the control of braking. No evidence was found that short followers differ from long followers in the ability to accurately perceive TTC. There was, however, evidence that short followers are better able to programme the intensity of braking to required levels. Also, short followers tuned the control of braking better to the development of criticality in time during the braking process. It was concluded that short followers may differ from long followers in programming and execution of the braking response.

Accidents, Traffic↗