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Biomedical subjects

L Riddez

Publications and source records attributed to L Riddez.

15 recordsLinked to original sources
PubMed2001

High-dose intravenous infusion of irrigating fluids containing glycine and mannitol in the pig.

BACKGROUND: Large-scale absorption of electrolyte-free irrigating fluid during endoscopic surgery may result in a "transurethral resection syndrome." The severity of the syndrome can probably be modified by using mannitol 5% instead of the most widely used glycine 1.5%. METHODS: Seventeen pigs with a mean body weight of 22 (range 19-26) kg received an intravenous infusion of 100 mL kg(-1) h(-1) of either glycine 1.5% or mannitol 5% over 90 min. Central hemodynamics, whole-body and brain oxygen consumption, intracranial pressure, blood hemoglobin, and the sodium concentrations in serum and urine were monitored for 120 min. Selected measurements were made on 6 other pigs given mannitol 3% and in 2 controls not given any fluid. Morphological examinations of the hearts were conducted. RESULTS: Both glycine 1.5% and mannitol 5% transiently increased cardiac output, the aortic blood flow rate, and arterial pressures, but all of these parameters fell to below baseline after the infusions were ended. The intracranial pressure was lower (P < 0.05) and the oxygen consumption in the brain decreased (P < 0.001) during the infusion of mannitol 5%. Glycine 1.5% expanded the intracellular volume more than mannitol did (P < 0.002). Signs of myocardial damage were graded glycine 1.5% > mannitol 5% > mannitol 3%. CONCLUSIONS: Massive infusion of glycine 1.5% and mannitol 5% left the pigs in a hypokinetic hypotensive state. Glycine 1.5% increased the intracranial pressure and injured the myocardium more than mannitol 5%, which then seems to be a more appropriate irrigating fluid to use during endoscopic surgery.

Animals↗
PubMed2001

Early resuscitation with hypertonic saline/dextran in uncontrolled intra-abdominal bleeding in swine combined with a soft tissue gunshot wound.

The effects of hypertonic saline/dextran (HSD) on hemodynamics and on rebleeding were studied during an uncontrolled intra-abdominal hemorrhage combined with a high-energy gunshot wound (GSW) in the hind limb of anesthetized swine. The GSW had instant effects on the central hemodynamics, which were aggravated when the internal hemorrhage was induced. Compared with baseline, cardiac output decreased to about 42%, mean arterial pressure decreased to 52 +/- 4%, and mean flow rates in the splanchnic region, in the upper aorta, and in the kidney decreased to 51 to 15%. The injection of HSD at 10 minutes was followed by a prompt increase in blood flow rates, but rebleeding occurred in five of eight animals, although only two died. In conclusion, GSW induced instant changes in hemodynamics at distance from the injury. When HSD treatment was given in a bolus injection, rebleeding occurred in five of eight animals, although the second hemorrhage became fatal in only one animal.

Animals↗
PubMed1999

[Aggravated uncontrolled hemorrhage induced by intravenous fluid administration].

A model of uncontrolled haemorrhage where a 0.5 mm laceration is made in the porcine abdominal aorta has shown outcome to be impaired by conventional fluid therapy given to restore blood volume. Findings in recent studies where the difference in blood flow rates, proximal vs. distal to the site of vascular lesion, was used as a measure of bleeding suggest the adverse effect of fluid therapy to be strongly associated with re-bleeding after primary haemostasis has occurred. Optimal survival is dependent on a fluid infusion rate ensuring balance between the risk of re-bleeding and the beneficial effects of fluid therapy on oxygen consumption.

Animals↗
PubMed1999

[More precise indications for fluid therapy during transportation to hospital are required].

Although early intravenous fluid therapy for haemorrhage and shock is usually given before arrival at the hospital, its value is unclear and more precise indications are needed. The indications will take into account such factors as transport time, volume and type of bleeding, and the presence or absence of concomitant head injury. Fluid resuscitation can be omitted if transport time is less than 30 min, but may be beneficial if it is more than 30 min. Choice of infusion rate should be guided by the estimated risk of re-bleeding when haemorrhage is uncontrolled, and by cerebral perfusion where severe head injury is present.

Ambulances↗
PubMed1999

Early hemodynamic changes during uncontrolled intra-abdominal bleeding.

Central hemodynamics was studied in 32 pigs during the first 10 min after making a 5-mm laceration in the infrarenal aorta. Blood flow probes were placed proximally and distally to the site of the bleeding and also over the portal vein and renal artery. We found that the bleeding, which was indicated by a difference in the rate of blood flow between the two aortic probes, stopped spontaneously after about 3 min. The short-term changes in blood flow rates closely followed simple monoexponential functions with mean half-times of 34 (proximal aorta), approximately 10 (lower aorta), 27 (splanchnic) and 21 s (kidney) to reach steady-state levels amounting to 20, 20, 27 and 8% of the baseline flow rates, respectively.

Adaptation, Physiological↗
PubMed1998

Central and regional hemodynamics during crystalloid fluid therapy after uncontrolled intra-abdominal bleeding.

OBJECTIVE: To study the effect of graded crystalloid fluid resuscitation on central hemodynamics and outcome after intra-abdominal hemorrhage. METHODS: Ten minutes after a 5-mm long laceration was produced in the infrarenal aorta, 32 pigs were randomized to receive either no fluid or Ringer's solution in the proportion 1:1, 2:1, or 3:1 to the expected amount of blood lost per hour (26 mL kg[-1]) over 2 hours. The hemodynamics were studied using arterial and pulmonary artery catheters and four blood flow probes placed over major blood vessels. RESULTS: During the first 40 minutes after the injury, the respective blood flow rates in the distal aorta were 39% (no fluid), 41% (1:1), 56% (2:1), and 56% (3:1) of the baseline flow. Fluid resuscitation increased cardiac output but had no effect on arterial pressure, oxygen consumption, pH, or base excess. Rebleeding occurred only with the 2:1 and 3:1 fluid programs. Survival was highest with the 1:1 and 2:1 programs. CONCLUSIONS: Crystalloid fluid therapy improved the hemodynamic status but increased the risk of rebleeding. Therefore, a moderate fluid program offered the best chance of survival.

Animals↗
PubMed1998

Central and regional hemodynamics during uncontrolled bleeding using hypertonic saline dextran for resuscitation.

The effects of hypertonic (7.5%) saline/6% dextran 70 (HSD) on central and regional hemodynamics were studied during uncontrolled intra-abdominal bleeding in 16 anesthetized pigs. Ultrasonic flow probes were placed proximally and distally to an aortic injury to indicate the incidence and extent of rebleeding after injecting 4 mL kg(-1) (N = 8) and 2.65 mL kg(-1) (N = 8) of HSD 10 min after the vascular injury was induced. The initial aortic bleeding reduced the blood flow rates to 71% of baseline in the skin, 53% in the splanchnic region, 42% in the upper aorta, and 15% in the kidney. Cardiac output dropped to 46% and the mean arterial pressure to 57% of baseline. The injection of HSD was followed by a prompt increase in all blood flow rates, but rebleeding started within 2 min in 13 of the pigs (81%). A second period of rebleeding occurred in six of them. The rebleeding averaged 300 mL, which is 62% of the blood lost when the aortic injury was induced. There was no significant difference between the treatment groups with respect to these blood losses or to the oxygen consumption, which was not restored by HSD. Five animals in each treatment group died after about 70 min, while the remaining six pigs (38%) survived the 120 min study period. These results suggest that HSD in the recommended dose, and even two-thirds thereof, promotes rebleeding when given shortly after a low energy intra-abdominal aortic injury. The fluid seems to have no beneficial effect on this type of uncontrolled hemorrhage.

Animals↗
PubMed1997

Breast conserving surgery for invasive breast cancer: risk factors for ipsilateral breast tumor recurrences.

To identify risk factors associated with an increased risk for ipsilateral breast tumor recurrence following breast-conserving surgery, a cohort of 759 women with T1-T2 tumors were studied. The majority of the patients (88%) had received postoperative radiation therapy to the breast. Median follow-up time was 10 (range: 6-17) years. There was a 1-1.5% yearly increase in ipsilateral breast tumor recurrences. For women < 50 ys the cumulative recurrence rate at 10 years was 18% and for women > or = 50 ys, 9%. Node positive women had a cumulative breast recurrence rate of 25% versus 10% for node negative women. Ten years postoperatively, irradiated patients had a cumulative recurrence rate of 11% versus 26% when no irradiation was given. The beneficial effect of radiotherapy was substantial during the first four postoperative years. The relative risk for an ipsilateral breast tumor recurrence during this period was 4.5 times higher than for non-irradiated patients. However, the protective effect of radiotherapy decreased with time. After ten years the relative risk of ipsilateral breast tumor recurrence was the same among irradiated and non-irradiated patients although the number of events during this period was low. Univariate analysis showed that seven factors were significantly associated with an increased risk of ipsilateral breast tumor recurrence, namely age < 50 ys, increasing tumor size, uncertain microscopic margins, axillary lymph node metastases, no postoperative tamoxifen treatment, premenopausal status, and no postoperative radiotherapy. Three factors remained independently significant after multivariate analysis: age < 50 ys, no postoperative radiation therapy, and positive lymph nodes. In conclusion, radiotherapy reduced the breast recurrence rate, but the effect decreased with time. Node-negative women > or = 50 were a low risk-group for ipsilateral breast tumor recurrence, with a cumulative risk at 10 years of 9% without radiation therapy and 5% with breast irradiation.

Adult↗
PubMed1997

Central and regional hemodynamics during acute hypovolemia and volume substitution in volunteers.

OBJECTIVES: To study the central and regional hemodynamics and oxygen consumption during acute hypovolemia and volume replacement with crystalloid and colloid solutions. DESIGN: Prospective, randomized, laboratory investigation. SETTING: Clinical physiology department at a university hospital. SUBJECTS: Eighteen healthy male volunteers, between 21 and 35 yrs of age (mean 26). INTERVENTIONS: Catheters were inserted in the cubital vein, brachial artery, pulmonary artery, thoracic aorta, right hepatic vein, and left renal vein for measurements of systemic arterial and pulmonary arterial pressures, total and central blood volumes, extravascular lung water, and the splanchnic (liver) and renal blood flow rates. The exchange of respiratory gases was measured, using the Douglas bag technique. Measurements were made before and after a venesection of 900 mL and again after the subjects had been randomized and received volume replacement with either 900 mL of Ringer's acetate solution 900 mL of albumin 5%, or 900 plus 900 mL of Ringer's solution. MEASUREMENTS AND MAIN RESULTS: Withdrawal of 900 mL of blood decreased cardiac output and the splanchnic and renal blood flow rates by between -16% and -20%. The oxygen uptake decreased by 13% in the whole body, while it remained unchanged in the liver and kidney. The systemic and pulmonary vascular resistances increased, while the extravascular lung water decreased. Autotransfusion of fluid from tissue to blood was indicated by hemodilution, which was most apparent in subjects showing only a minor change in peripheral resistance. Cardiac output, blood volume, and systemic vascular resistance were significantly more increased by infusion of 900 mL of albumin 5% than by 900 mL of Ringer's solution. However, infusion of 1800 mL of Ringer's solution increased the extravascular lung water and the pulmonary arterial pressures to significantly above baseline, while no significant difference from baseline was found after 900 mL of Ringer's acetate solution. CONCLUSIONS: Withdrawal of 900 mL of blood induces similar reductions in cardiac output as in the splanchnic and renal blood flow rates. A fluid shift from the extravascular to the intravascular fluid compartment might restore up to 50% of the blood loss. Optimal volume substitution with Ringer's solution can be effectuated by infusing between 100% and 200% of the amount of blood lost.

Acute Disease↗
PubMed1997

Haemodynamics during inhalation of a 50% nitrous-oxide-in-oxygen mixture with and without hypovolaemia.

BACKGROUND: Inhalation of a gas mixture containing 50% nitrous oxide in oxygen (N2O/O2) is widely used for pain relief in emergency situations, which may also be associated with blood loss. The aim of this study was to evaluate the haemodynamic effects of this gas mixture in normo- and hypovolaemic subjects. METHODS: Six healthy males were studied during inhalation of N2O/O2 before and after withdrawal of 900 ml of blood. On each occasion, we measured systemic and pulmonary arterial pressures, cardiac output, blood gases, extravascular lung water, and the blood flow and oxygen consumption in the whole body, liver and kidneys. RESULTS: Inhalation of N2O/O2 reduced the stroke volume and increased peripheral resistance. Oxygen uptake decreased in the liver (-30%) and in the whole body (-23%). Blood withdrawal reduced the pulmonary arterial and central venous pressures (-30 to -50%) and further decreased stroke volume and the blood flows to the liver and the kidney (-15%). The extravascular lung water tended to increase both during inhalation of N2O/O2 and during hypovolaemia. CONCLUSION: N2O/O2 aggravated the hypokinetic circulation induced by hypovolaemia. However, the oxygen consumption decreased only during inhalation of N2O/O2. This opens up the possibility that the cardiodepression associated with N2O/O2 is caused by a change in metabolic demands.

Adult↗
PubMed1994

[Increased number of knife assaults inspite of the legislation. Record of injuries among 399 patients].

From January 1985 to September 1993, 399 patients (368 men and 31 women), median age 28 years (mean 31.1, range 16-71 years), were admitted with stab wounds due to assault. The number of stab wounds per patient was one (N = 268 patients), two (N = 63), three (N = 31), four (N = 15), five (N = 7), or more than five (N = 15). The series as whole (N = 399) accounted for 543 sites of injury. Upper extremity wounds were the most frequent (35 per cent); of 188 arm injuries, 60 per cent were in the left arm. The next most frequent site was the head and neck region (N = 105; 12 per cent), followed by the chest (N = 75; 14 per cent), abdomen (N = 66;12 per cent), lower extremities (N = 59;11 per cent), back (N = 48;9 per cent), and the male genitalia (N = 2;0.4 per cent). Ninety-five major operations were performed in 74 patients. Seven patients died, and 40 had somatic or cosmetic life-time sequelae.

Abdominal Injuries↗
PubMedDate not supplied

Short-term crystalloid fluid resuscitation in uncontrolled intra-abdominal bleeding in swine.

INTRODUCTION: Fluid therapy in uncontrolled bleeding is controversial. In a previously used experimental animal model of aortic injury, the outcome often was impaired by re-bleeding that began at least 20 minutes after crystalloid fluid resuscitation was initiated. Therefore, it was hypothesized that re-bleeding might be avoided if volume loading is carried out for 20 minutes and then discontinued. METHODS: Ten minutes after a 5 mm laceration was produced in the infra-renal aorta on eight anesthetized pigs, they received a 20-minute intravenous infusion of Ringer's solution in the ratio of 1:1 to the expected blood loss. Hemodynamics were studied for 120 minutes using arterial and pulmonary artery catheters and blood flow probes placed proximal and distal to the aortic lesion and around the left renal artery and portal vein. RESULTS: The bleeding stopped between three and four minutes after the onset of bleeding. The blood flow rate dropped to 38% (mean) of baseline in the splanchnic region, to 31% in the upper aorta, and to 13% in the kidney. The flow rates and the oxygen consumption increased transiently during fluid resuscitation, but never reached baseline levels. Re-bleeding amounted to about 15% of the initial bleeding and occurred in only three of the animals. Four of the pigs died of shock within 90 minutes (range 47-85 minutes) after the aortic injury. CONCLUSION: Short-term crystalloid fluid therapy in uncontrolled aortic hemorrhage transiently improved the hemodynamic status and the oxygen consumption following the initial bleeding. Furthermore, the infusion did not cause re-bleeding of more than 100 ml, which occurred in previously conducted experiments when the infusion was continued for more than 20 minutes.

Animals↗