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Biomedical subjects

I L Kanstrup

Publications and source records attributed to I L Kanstrup.

At least 19 recordsLinked to original sources
PubMed2001

Optimizing peroperative compliance with PEEP during upper abdominal surgery: effects on perioperative oxygenation and complications in patients without preoperative cardiopulmonary dysfunction.

BACKGROUND AND OBJECTIVE: Late postoperative hypoxaemia after upper abdominal surgery is common even among cardiopulmonary healthy patients. Atelectasis may develop after intubation and persist into or reveal a disposition for atelectasis in the postoperative period. Positive end-expiratory pressure (PEEP) eliminates peroperative atelectasis but the effect on perioperative oxygenation is controversial. This study evaluated the effect of peroperative PEEP optimized pulmonary compliance on perioperative oxygenation and complications. METHODS: Forty patients assessed by electrocardiography, spirometry, functional residual capacity and diffusion capacity were randomly assigned to receive positive end-expiratory pressure (PEEP) or zero end-expiratory pressure (ZEEP) during surgery. PaO2, SPO2 and complications in the postoperative period were evaluated without knowledge of peroperative PEEP or ZEEP application. RESULTS: Peroperative arterial oxygenation improved for all patients receiving PEEP, mean 2.1 kPa (0.7-3.5 kPa). There was no difference in postoperative median PaO2 between the groups. The differences in the incidence of late prolonged postoperative hypoxaemia and complications were 25% (-5% to 55%) and -1% (-31% to 29%) between the ZEEP and the PEEP group, but were not statistically significant.

Abdomen↗
PubMed2001

Heart rate response to hypoxic exercise: role of dopamine D2-receptors and effect of oxygen supplementation.

This study examined the effects of dopamine D(2)-receptor blockade on the early decrease in maximal heart rate at high altitude (4559 m). We also attempted to clarify the time-dependent component of this reduction and the extent to which it is reversed by oxygen breathing. Twelve subjects performed two consecutive maximal exercise tests, without and with oxygen supplementation respectively, at sea level and after 1, 3 and 5 days at altitude. On each study day, domperidone (30 mg; n=6) or no medication (n=6) was given 1 h before the first exercise session. Compared with sea level, hypoxia progressively decreased the maximal heart rate from day 1 and onwards; also, hypoxia by itself increased plasma noradrenaline levels after maximal exercise. Domperidone further increased maximal noradrenaline concentrations, but had no effect on maximal heart rate. On each study day at altitude, oxygen breathing completely reversed the decrease in maximal heart rate to values not different from those at sea level. In conclusion, dopamine D(2)-receptor blockade with domperidone demonstrates that hypoxic exercise in humans activates D(2)-receptors, resulting in a decrease in circulating levels of noradrenaline. However, dopamine D(2)-receptors are not involved in the hypoxia-induced decrease in the maximal heart rate. These data suggest that receptor uncoupling, and not down-regulation, of cardiac adrenoreceptors, is responsible for the early decrease in heart rate at maximal hypoxic exercise.

Adult↗
PubMed2000

Bone loss after renal transplantation: role of hyperparathyroidism, acidosis, cyclosporine and systemic disease.

UNLABELLED: In order to determine risk factors for bone loss after renal transplantation, dual energy X-ray absorptiometry was performed in 125 renal transplant patients. The bone mineral density (BMD) was expressed as a percentage of the normal population (BMD%) and Z-score (SD from normal). The whole body, lumbar spine and femoral neck BMD% (Z-score) values were 93.9 +/- 8.9 (-0.90 SD), 91.6 +/- 14.9 (-0.98 SD) and 87 +/- 15.3 (-1.0 SD)%, respectively. Low BMD% was associated with low creatinine clearance ( < 40 mL/min: 91.6 +/- 7.9, > 40 mL/min: 95.6 +/- 8.0, p < 0.01), repeated graft loss (0: 94.4 +/- 9.1, > 1: 87.4 +/- 9.3, p < 0.05), long dialysis duration ( < 1 yr: 95.2 +/- 7.9, > 5: 90.1 +/- 10.6, p < 0.05), acidosis (bicarbonate < 21 mmol/L: 89.6 +/- 8.0, > 27: 96.7 +/- 7.2, p < 0.01), secondary and tertiary hyperparathyroidism ( < 50 ng/L: 95.9 +/- 7.1, > 200: 87.7 +/- 5.0, p < 0.01), raised alkaline phosphatase ( < 200 units/L: 95.7 +/- 7.2, > 300: 85.6 +/- 13.2, p < 0.001), osteocalcin ( < 50 microg/L: 95.2 +/- 6.7, > 100: 89.3 +/- 7.6, p < 0.01) and urinary deoxypyridinoline (< 5 nM/mM creatinine: femoral neck 89.6 +/- 10.7, > 10: 82.1 +/- 20.1, p < 0.05), low 25-OH-vitamin D ( < 10 microg/L: 91.3 +/- 9.8, > 20: 96.9 +/- 7.4, p < 0.001) and high cyclosporine concentration (0 ng/L: 98.3 +/- 7.0, > 150: 92.1 +/- 9.3, p < 0.05). Patients with clinical atherosclerosis (91.7 +/- 8.6 vs. 95.4 +/- 8.8, p < 0.01), hypoalbuminemia ( < 550 micromol/L: 87.6 +/- 13.2, > 550: 94.2 +/- 7.8, p < 0.01), renovascular disease (89.7 +/- 5.7 vs. 95.0 +/- 5.7, p < 0.05) and diabetic nephropathy (femoral neck 76.6 +/- 8.8 vs. 89.3 +/- 15.1, p < 0.01) had lower bone masses. High bone mass was associated with previous dialysis alphacalcidol therapy (0: 92.2 +/- 7.5, > 3 microg/wk: 97.3 +/- 6.9, p < 0.05). No relationships with transplantation duration, 1,25-OH-vitamin D, aluminium, calcium or steroid dose were found. No involutional changes in tertiary hyperparathyroidism could be discerned. CONCLUSION: The major threats to bone mass after renal transplantation appear to be ongoing hyperparathyroid bone disease, low renal function, acidosis, systemic disease and hypo-vitaminosis D.

Absorptiometry, Photon↗
PubMed2000

PaO2 during anaesthesia and years of smoking predict late postoperative hypoxaemia and complications after upper abdominal surgery in patients without preoperative cardiopulmonary dysfunction.

BACKGROUND: The incidence of late postoperative hypoxaemia and complications after upper abdominal surgery is 20-50% among cardiopulmonary healthy patients. Atelectasis development during anaesthesia and surgery is the main hypothesis to explain postoperative hypoxaemia. This study tested the predictive value of PaO2<19 kPa during combined general and thoracic epidural anaesthesia and the preoperative functional residual capacity (FRC) reduction in the 30 degree head tilt-down position for the development of late prolonged postoperative hypoxaemia, PaO2<8.5 kPa for a minimum of 3 out of 4 days, and other complications. Forty patients without cardiopulmonary morbidity, assessed by ECG, spirometry, FRC and diffusion capacity preoperatively, underwent upper abdominal surgery. PaO2 during anaesthesia and preoperative FRC reduction were compared to known risk factors for the development of hypoxaemia and complications: age, pack-years of smoking and duration of operation. The effect of optimizing pulmonary compliance with peroperative positive end-expiratory pressure (PEEP) on postoperative hypoxaemia and complications was evaluated in a blinded and randomized manner. RESULTS: Late prolonged postoperative hypoxaemia and other complications were found in 37% and 38% of the patients, respectively. Patients with PaO2>19 kPa during anaesthesia with F(I)O2=0.33 exhibited a risk, irrespective of PEEP status, of suffering late prolonged hypoxaemia of 0% (0;23) and patients with PaO2<19 kPa a risk of 52% (32;71), P<0.005. Having smoked more than 20 pack-years was associated with a 47% (19;75) higher incidence of postoperative complications than having smoked less than 20 pack-years, P<0.006. CONCLUSIONS: PaO2 during anaesthesia and smoked pack-years provide new tools evaluating patients undergoing upper abdominal surgery in order to predict the patients who develop late postoperative hypoxaemia and complications.

Abdomen↗
PubMed1999

Effectiveness of active physical training as treatment for long-standing adductor-related groin pain in athletes: randomised trial.

BACKGROUND: Groin pain is common among athletes. A major cause of long-standing problems is adductor-related groin pain. The purpose of this randomised clinical trial was to compare an active training programme (AT) with a physiotherapy treatment without active training (PT) in the treatment of adductor-related groin pain in athletes. METHODS: 68 athletes with long-standing (median 40 weeks) adductor-related groin pain--after examination according to a standardised protocol--were randomly assigned to AT or PT. The treatment period was 8-12 weeks. 4 months after the end of treatment a standardised examination was done. The examining physician was unaware of the treatment allocation. The ultimate outcome measure was full return to sports at the same level without groin pain. Analyses were by intention to treat. FINDINGS: 23 patients in the AT group and four in the PT group returned to sports without groin pain (odds ratio, multiple-logistic-regression analysis, 12.7 [95% CI 3.4-47.2]). The subjective global assessments of the effect of the treatments showed a significant (p=0.006) linear trend towards a better effect in the AT group. A per-protocol analysis did not show appreciably different results. INTERPRETATION: AT with a programme aimed at improving strength and coordination of the muscles acting on the pelvis, in particular the adductor muscles, is very effective in the treatment of athletes with long-standing adductor-related groin pain. The potential preventive value of a short programme based upon the principles of AT should be assessed in future, randomised, clinical trials.

Adolescent↗
PubMed1999

The effect of thoracentesis on lung function and transthoracic electrical bioimpedance.

This study aimed to determine the relationship between improvement in lung function and changes in transthoracic electrical bioimpedance (TEB) after thoracentesis in patients with pleural effusions. Fifteen patients with pleural effusions due to either malignant (n = 8) or cardiac (n = 7) diseases were included. Pulmonary function was assessed before and after thoracentesis. During thoracentesis the patients were monitored with TEB. Using linear correlation analysis, the increases for each litre of aspirated thoracic fluid were: forced expiratory volume in 1 s (FEV1) 0.261; forced vital capacity (FVC) 0.331; total lung capacity (TLC) 0.58; and the lung diffusing capacity (DLCO); 2.4 ml min-1 mmHg-1. Baseline impedance increased by 2.3 Ohm l-1 aspirated thoracic fluid. The relative increase in baseline impedance was twice as high for patients with cancer as for patients with heart failure (P < 0.05). We found only minor changes in systolic blood pressure and mean arterial pressure. The improvements in diffusing capacity, airflow, and lung volumes after thoracentesis are correlated to an increase in baseline impedance, but changes are dependent on the primary disease.

Aged↗
PubMed1999

Pulmonary damage after modest exposure to zinc chloride smoke.

Thirteen soldiers (11 men and two women) were exposed to zinc chloride smoke (ZCS) during a combat exercise. Even though their initial symptoms were modest, a prolonged follow up with lung function testing and blood samples was undertaken due to previous cases with fatal outcome after exposure to ZCS. Four weeks after exposure there were statistically significant declines from baseline values in lung diffusion capacity and total lung capacity of 16.2% and 4.3%, respectively. At the same time plasma levels of fibrinogen and zinc were significantly elevated, though mainly within the normal range. All variables showed a tendency towards normalization at follow up 8 weeks and 6 months after exposure. These findings indicate an unexpected quantifiable damage to lung parenchyma with a remarkable delay after modest exposure to zinc chloride smoke despite sparse initial symptoms. Exposure to high concentrations of ZCS may induce adult respiratory distress syndrome (ARDS) after a symptom free period of up to 12 days from exposure. Even though none of the soldiers in the present study developed ARDS the assessment of lung diffusion capacity and acute phase reactants is proposed as a supplement when monitoring patients after exposure to ZCS.

Adult↗
PubMed1999

Blood pressure and plasma catecholamines in acute and prolonged hypoxia: effects of local hypothermia.

This study measured the pressor and plasma catecholamine response to local hypothermia during adaptation to hypobaric hypoxia. Eight healthy men were studied at rest and after 10 and 45 min of local cooling of one hand and forearm as well as after 30 min of rewarming at sea level and again 24 h and 5 days after rapid, passive transport to high altitude (4,559 m). Acute mountain sickness scores ranged from 5 to 16 (maximal attainable score: 20) on the first day but were reduced to 0-8 by the fifth day. Systolic blood pressure, heart rate, and plasma epinephrine increased on day 1 at altitude compared with sea level but declined again on day 5, whereas diastolic and mean blood pressures continued to rise in parallel with plasma norepinephrine. With local cooling, an increased vasoactive response was seen on the fifth day at altitude. Very high pressures were obtained, and the pressure elevation was prolonged. Heart rate increased twice as much on day 5 compared with the other two occasions. Thoracic fluid index increased with cooling on day 5, suggesting an increase in pulmonary vascular resistance. In conclusion, prolonged hypoxia seems to elicit an augmented pressor response to local cooling in the systemic and most likely also the pulmonary circulation.

Acute Disease↗
PubMed1999

Non-steroidal anti-inflammatory drugs and renal response to exercise: a comparison of indomethacin and nabumetone.

Nabumetone, a newer non-steroidal anti-inflammatory drug (NSAID) which preferentially blocks cyclo-oxygenase-2 activity, may be less nephrotoxic than indomethacin. This study tested whether nabumetone has effects different from those of indomethacin on exercise-induced changes in renal function and the renin-aldosterone system. In a randomized fashion, ten subjects were studied after indomethacin (100 mg), nabumetone (1 g) or no medication (control) administered orally at 22.00 hours on the day before each study day, and again at 8.00 hours upon arrival at the laboratory. Renal function was studied at baseline, during graded 20-min exercise sessions at 25%, 50% and 75% of the maximal oxygen uptake rate, and subsequently during two 1-h recovery periods. Heart rate, arterial blood pressure, cardiac output and plasma catecholamines at rest and during exercise were not altered by indomethacin or nabumetone. Indomethacin decreased urinary rates of excretion of 6-oxo-prostaglandin F(1alpha) (6-oxo-PGF(1alpha)) and thromboxane B(2) in all study periods. Nabumetone decreased 6-oxo-PGF(1alpha) excretion during and after exercise. Excretion rates for PGE(2) did not change. Neither indomethacin nor nabumetone changed baseline values or exercise-induced decreases in renal plasma flow or glomerular filtration rate. Indomethacin, but not nabumetone, decreased sodium excretion, urine flow rate and free water clearance. The renal response to exercise, however, remained unchanged. In contrast with nabumatone, indomethacin decreased the plasma renin concentration. Thus, during exercise, nabumetone may decrease the excretion of 6-oxo-PGF(1alpha) by inhibition of cyclo-oxygenase-1 or by inhibition of specific exercise-induced activation of cyclo-oxygenase-2, or both. None of the drugs changed the renal response to exercise. Inhibition by indomethacin of angiotensin II and thromboxane A(2) synthesis may, during exercise, counterbalance renal vasoconstriction caused by blockade of vasodilatory prostaglandins.

Adult↗
PubMed1998

Changes in bone mineral density adjacent to two biomechanically different types of cementless femoral stems in total hip arthroplasty.

We have compared the differences in bone mineral density (BMD) adjacent to two biomechanically different cementless femoral stems used for total hip arthroplasty. Measurements were performed 12 to 38 months after surgery in a cross sectional study of 29 patients. Of these, 15 had arthroplasties using an "off the shelf" type cementless femoral stem (Spotorno), while 14 had a custom made cementless stem (Evolution-K). Dual X-ray absorptiometry (DXA) measurements revealed that the patients who had a Spotorno stem had a significantly lower BMD in the operated leg compared to the non-operated side in both Gruen zones 1 and 7, whereas no significant differences were found in these areas in the Evolution-K group. For both types of prosthesis there was a significant and similar decrease in BMD of the proximal tibia on the operated side.

Absorptiometry, Photon↗
PubMed1998

Bone loss after hip fracture is correlated to the postoperative degree of mobilisation.

This study quantifies changes in bone mineral density (BMD) in the opposite hip and in both proximal tibiae and the correlation with the use of walking aids for patients with two types of hip fracture during the 1st year after surgery. In all, 26 women and 15 men aged 42-88 years (median 71 years) were included. Twenty-one patients had an intracapsular hip fracture (ICF) and 20 had an intertrochanteric fracture (ITF). All patients were treated with a dynamic hip screw. BMD was measured by dual X-ray absorptiometry (DXA; LUNAR, Wisconsin) within the 1st week after surgery and after 3, 6 and 12 months. Initial BMD of the non-fractured hip was significantly lower for both fracture groups compared with reference material. For both fracture types there was a significant decrease in BMD of the non-fractured hip and proximal tibia of the fractured leg during the first 3 months, which still persisted a year after surgery. Improved mobilisation between two examinations was positively correlated with changes in BMD of the proximal tibia of the fractured leg and the non-fractured hip.

Adult↗
PubMed1998

Plasma volume in acute hypoxia: comparison of a carbon monoxide rebreathing method and dye dilution with Evans' blue.

Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV[Evans']) with a carbon monoxide (CO) rebreathing method (PV[CO]) for measurements of PV in ten normal subjects at sea level and again 24 h after rapid passive ascent to high altitude (4,350 m). Hypobaric hypoxia decreased arterial oxygen saturation to 79 (74-83)% (mean with 95% confidence intervals). The PV(Evans') remained unchanged from 3.49 (3.30-3.68) l at sea level to 3.46 (3.24-3.68) l at high altitude. In contrast PV(CO) decreased from 3.39 (3.17-3.61) l at sea level to 3.04 (2.75-3.33) l at high altitude (P < 0.05). Compared with sea level, this resulted in an increase of the mean bias between the two methods [from 0.11 (-0.05-0.27) l at sea level to 0.43 (0.26-0.60) l at high altitude] so that the ratio between PV(Evans') and PV(CO) increased from 1.04 (0.99-1.09) at sea level to 1.15 (1.06-1.24) at high altitude (P < 0.05). In conclusion, the two methods were not interchangeable as measures of hypoxia-induced changes in PV. The mechanism responsible for the bias remains unknown, but it is suggested that the results may reflect a redistribution of albumin caused by the combined effects in hypoxia of both an increased capillary permeability to albumin and a decrease in PV. As a result, the small perivascular compartment of albumin beyond the endothelium may increase without changes in the overall albumin distribution volume.

Acute Disease↗
PubMed1998

Acute cardiovascular effect of 1,25-dihydroxycholecalciferol in essential hypertension.

A role for vitamin D in the pathophysiology of essential hypertension has frequently been suggested, but acute direct effects on blood pressure, cardiac output, renal hemodynamics, or hormones have not previously been demonstrated. The rapid effects of 1,25-dihydroxycholecalciferol (1,25-D) were assessed over 120 min after a bolus injection (0.02 microg/kg body weight) in eight men with essential hypertension and in nine healthy men. A placebo group of 10 healthy men was also included. Ionized calcium was monitored closely during the study, and was kept constant with a clamping technique. In the hypertensive patients, a transient increase in blood pressure and a reciprocal fall in cardiac output measured by a CO2 rebreathing technique (-15%, P < .05) were observed after 1,25-D injection. In the control group, both blood pressure and cardiac output remained unchanged. The glomerular filtration rate, effective renal plasma flow, and urinary sodium and water excretions were unchanged in both groups. Plasma levels of atrial natriuretic peptide at baseline were higher in the hypertensive patients than in the control subjects (P < .02); plasma levels of renin, aldosterone, norepinephrine, endothelin, and parathyroid hormone(1-84) were similar in the two groups. None of these hormones was affected during the observation time after the injection of 1,25-D. In conclusion, acute administration of 1,25-D caused a fast and likely nongenomic-mediated decrease in cardiac output in patients with essential hypertension, which together with a transient BP increase implies a 1,25-D-induced increase in total peripheral resistance. These data suggest an enhanced cardiovascular responsiveness to 1,25-D in hypertensive compared to healthy normotensive subjects.

Adult↗
PubMed1998

Effects of hyperventilation and hypocapnic/normocapnic hypoxemia on renal function and lithium clearance in humans.

BACKGROUND: Using the renal clearance of lithium as an index of proximal tubular outflow, this study tested the hypothesis that acute hypocapnic hypoxemia decreases proximal tubular reabsorption to the same extent as hypocapnic normoxemia (hyperventilation) and that this response is blunted during normocapnic hypoxemia. METHODS: Eight persons were studied on five occasions: (1) during inhalation of 10% oxygen (hypocapnic hypoxemia), (2) during hyperventilation of room air leading to carbon dioxide values similar to those with hypocapnic hypoxemia, (3) during inhalation of 10% oxygen with the addition of carbon dioxide to produce normocapnia, (4) during normal breathing of room air through the same tight-fitting face mask as used on the other study days, and (5) during breathing of room air without the face mask. RESULTS: Hypocapnic and normocapnic hypoxemia and hyperventilation increased cardiac output, respiratory minute volume, and effective renal plasma flow. Glomerular filtration rate remained unchanged on all study days. Calculated proximal tubular reabsorption decreased during hypocapnic hypoxemia and hyperventilation but remained unchanged with normocapnic hypoxemia. Sodium clearance increased slightly during hypocapnic and normocapnic hypoxemia, hyperventilation, and normocapnic normoxemia with but not without the face mask. CONCLUSIONS: The results indicate that (1) respiratory alkalosis with or without hypoxemia decreases proximal tubular reabsorption and that this effect, but not renal vasodilation or natriuresis, can be abolished by adding carbon dioxide to the hypoxic gas; (2) the increases in the effective renal plasma flow were caused by increased ventilation rather than by changes in arterial oxygen and carbon dioxide levels; and (3) the natriuresis may be secondary to increased renal perfusion, but application of a face mask also may increase sodium excretion.

Adult↗