Early and late results of controlled ventilation in flail chest.

From 1967 through 1974, a consecutive series of 35 patients with flail chest were treated with intermittent positive-pressure breathing (IPPB). The controlled ventilation contributed to stabilization of the thoracic cage in a favorable position for healing of the fractures. Surgical stabilization of the chest was not attempted in any of the cases. During treatment with IPPB, one patient died from profuse bleeding due to a generalized coagulation disorder, but the remaining 34 were discharged in a satisfactory respiratory condition. A late follow-up study of the pulmonary function one to eight years after the trauma included x-ray films of the trachea and lungs, kymographic studies of the diaphragm, spirometric and radiospirometric testing, and arterial blood gas levels. Eighteen patients were examined. Spirometric testing revealed astonishingly little impairment of the total pulmonary function. The radiospirometric studies with 133xenon showed a significant reduction of the regional perfusion only in five patients (2 to 4.5 pulmonary segments). Kymographic study of the diaphragm gave no further information and was less selective compared with the other tests of pulmonary function. Owing to the encouraging early and late results in this study, early treatment with IPPB is considered to be the method of choice in flail chest with paradoxic respiratory movements.

Noninvasive measurement of diameter changes in the distal abdominal aorta in man.

An ultrasound phase-locked, echo-tracking system was used to determine the dynamic properties of the distal abdominal aorta in 10 Caucasian male subjects (mean age, 25 years). Recordings were made at rest and during the blood pressure increase resulting from isometric exercise. The pressure diameter curve was nonlinear with an inflection at about 90-110 mmHg. Above this pressure range, the vessel was stiffer (less compliant), but the pressure diameter relationship was roughly linear above as well as below the inflection. Individual pressure diameter curves showed hysteresis, i.e., the aorta had a smaller diameter during expansion than during retraction at corresponding pressures. The pressure strain elastic modulus (Ep) and stiffness (beta) were at rest [Mean Arterial Pressure (MAP), 81 mmHg] 0.70 10(5) N/m2 and 6.0, respectively. During isometric exercise (MAP, 122 mmHg), Ep increased significantly by 91% and stiffness (beta) nonsignificantly by 27%. The variability of the compliance determinations was 5% when the ultrasonic system was combined with intra-arterial blood pressure measurements and less than 7% when combined with auscultatory blood pressure measurements. It is concluded that the phase-locked, echo-tracking system fulfills clinical requirements for routine measurements of vascular compliance.

Acute effects of doxazosin and atenolol on smoking-induced peripheral vasoconstriction in hypertensive habitual smokers.

The acute effects of selective alpha 1 inhibition with doxazosin (0.5-0.7 mg intravenously) and beta 1-blockade with atenolol (0.1 mg/kg body weight, intravenously) on smoking-induced peripheral vasoconstriction were investigated in 24 hypertensive habitual smokers. Forearm blood flow was measured by venous occlusion plethysmography and skin blood flow was estimated by thermography and laser doppler flowmetry. After the patients had smoked two cigarettes, plasma adrenaline elevations were similar under basal conditions and after drug administration; plasma noradrenaline remained unchanged. The smoking-induced increase in the heart rate was attenuated by atenolol compared with basal values. The smoking-induced increase in systolic blood pressure was more marked after atenolol and doxazosin (P less than 0.05) than before the drug administration. The smoking-induced increase in diastolic blood pressure was enhanced by atenolol (P less than 0.05) but unchanged by doxazosin. Smoking increased forearm vascular resistance under basal conditions (P less than 0.05) and after atenolol (P less than 0.01) but not after doxazosin. Similarly, skin temperature was significantly reduced by smoking under basal conditions and after the administration of atenolol (P less than 0.001) but not doxazosin. The smoking-induced reduction in skin blood flow was attenuated by doxazosin compared with atenolol (P less than 0.05). Thus, smoking-induced muscular and cutaneous vasoconstriction was inhibited by doxazosin as opposed to atenolol in hypertensive habitual smokers. This may reflect unmasked beta-adrenoceptor mediated vasodilation in addition to attenuated alpha 1-adrenoceptor mediated vasoconstriction.

Plasma catecholamine levels in the coronary sinus, the left renal vein and peripheral vessels in healthy males at rest and during exercise.

Noradrenaline and adrenaline were determined in blood samples from the brachial vein, the brachial artery, the left renal vein and the femoral vein in 6 healthy males (aged 23-35 y). In 3 of the subjects catecholamines were determined also in blood from the coronary sinus. All samples were taken simultaneously in supine postion after 30 min of rest and then in connection with exercise in supine position using a bicycle ergometer, firstly with a work load of 50 W for 9 min and secondly with a work load of 150 W for the same period of time. Under resting conditions the catecholamine levels were about the same at all locations, the mean for noradrenaline being 1.59 nmol/1 with a range of 1.30-2.11 nmol/1 and for adrenaline 0.46 nmol/1 and 0.23-0.65 nmol/1, respectively. At 50 W the noradrenaline concentration increased significantly in the brachial artery, the left renal vein and the femoral vein, whereas adrenaline increased significantly only in the femoral vein. At 150 W the noradrenaline content increased markedly in all samples, especially in the left renal vein (mean increase 13.02 nmol/1) and the coronary sinus (mean increase 13.06 nmol/1). Adrenaline concentration increased significantly in the brachial artery and the femoral vein. At 150 W the mean net output of noradrenaline as estimated from the calculated flows and actual AV-differences amounted to 2.25 nmol/min from the heart and to 0.36 nmol/min from the kidney.

Diagnosis of ventricular tachyarrhythmias by ambulatory electrocardiographic monitoring. Correlation with his bundle electrography.

The aim of the present study was to compare the prediction of bradyarrhythmias via the corrected sinus node recovery time and the His bundle electrogram with the findings made during long term electrocardiographic recording. Ninety-two patients, aged 17-88 years, were included in the study with a suspicion of Adams-Stokes' syndrome. During long term electrocardiographic recording only 40 patients had symptoms while 52 could not tolerate long term electrocardiographic recording until symptoms had appeared. Seven out 37 patients with sick sinus syndrome and 2 out of 9 with atrioventricular block 2 degrees/3 degrees had additional significant ventricular arrhythmias. A total of 10 patients had prolonged (greater than or equal to 160 msec) atrium to His intervals, among them 2 had significant ventricular arrhythmia but failed to have symptoms during long term electrocardiographic recording. In 22 patients the His to ventricle interval was moderately prolonged (56-79 msec), among them 7 had significant ventricular arrhythmias (5 with symptoms during long term electrocardiographic recording). Out of 5 patients with markedly H-V interval prolonged, 3 patients had 2 degrees/3 degrees atrio-ventricular block and 1 patient had atrial tachyarrhythmia during long term electrocardiographic recording. In conclusion prolonged H-V intervals are frequent in patients with episodic atrioventricular block but also in patients who have symptomatic ventricular tachyarrhythmias. Long term electrocardiographic recording is essential for the differentiation between symptomatic ventricular arrhythmia and symptomatic atrioventricular block in patients with prolonged HV-intervals.

Effect of upright tilting on kinins as compared to renin activity in the renal venous blood from patients with essential hypertension.

The effect of tilting on the release of renal kallikrein as compared to renin was studied by the determination of kinin concentration and plasma renin activity (PRA) in the renal veins in supine position and after 15 min of 45 degrees upright tilting in 10 patients with essential hypertension. Kinin concentration decreased from 0.62 +/- 0.05 microgram/1 (mean +/- S.E.M.) in supine position to 0.51 +/- 0.05 after tilting (p less than 0.01), while PRA increased from 2.84 +/- 0.39 microgram/1/3 h tpo 4.87 +/- 0.66 (p less than 0.001). These results indicate that tilting diminishes the release of renal kallikrein. It is suggested that decreased intrarenal generation of kinins may be of importance for the reduction of diuresis and natriuresis induced by tilting.

Renal venous output of kinins in patients with hypertension and unilateral renal artery stenosis.

In four patients with hypertension and angiographically pronounced unilateral renal artery stenosis, kallikrein activity was estimated in each kidney separately by the determination of kinin output in the renal veins. All patients showed suppression of renin release from the kidney with a non-stenotic artery. Accordingly, plasma flow from the kidney with artery stenosis could be estimated. The ratio of venous output of kinins between the kidney with a non-stenotic artery and the one with artery stenosis was 2.6-6.5. This indicates that renal artery stenosis leads to diminished intrarenal kinin generation. Reduced kinin formation may explain the low diuresis and natriuresis found in the kidney with artery stenosis.

Effect of xamoterol on exercise capacity and left ventricular function in angina pectoris and in dilated cardiomyopathy.

The present study evaluates the effect of the beta 1 partial agonist xamoterol in patients with coronary artery disease compared to the effect in patients with dilated cardiomyopathy. Nineteen patients with angina pectoris and nine patients with dilated cardiomyopathy received xamoterol 200 mg b.i.d. for 4 weeks in a placebo-controlled double-blind study. The effect was evaluated with a standardized exercise test and radionuclide angiocardiography with determination of global and regional ejection fraction. At rest xamoterol caused no significant changes among the angina patients while global and regional ejection fraction increased among the cardiomyopathy patients. During exercise, when the drug exerts a beta 1-antagonist effect, xamoterol increased the exercise performance among the angina pectoris patients. Fourteen out of 19 patients with angina pectoris were unable to increase their ejection fraction from rest to work due to coronary ischaemia. These 14 patients improved their global ejection fraction during work after xamoterol treatment.

Radionuclide left ventricular volume determination. Influence of scattered radiation and surrounding activity.

Radionuclide measurements of left ventricular volumes, ejection fractions and stroke volumes were performed by an equilibrium technique in nine patients using left anterior oblique projection and individual depth correction. Phantom studies were made in order to evaluate attenuation and scattering of the radiation. It was found that a simple depth correction factor, k(d) = e mu d, can be used under certain conditions. However, the determination of left ventricular volume by radionuclide techniques is not a truly absolute method. The depth correction factor to be used is dependent on the condition of measuring and evaluation, for instance how the region of interest for the left ventricle is selected. Therefore, this method should be carefully standardized, evaluated and compared to other techniques. Stroke volume measured by radionuclide and dye-dilution technique showed a correlation coefficient of 0.76 (nine patients) at rest and 0.77 (seven patients) at work. This method can be easily performed during routine ejection fraction determination and can thus be useful in clinical studies.

Increased arterial and venous plasma noradrenaline levels in patients with primary hypothyroidism during hypothyroid as compared to euthyroid state.

The use of venous plasma noradrenaline levels as a marker of general sympathetic tone has been questioned as changes in local sympathetic activity may influence the venous levels. To compare arterial and venous plasma noradrenaline levels in patients with primary hypothyroidism, arterial and venous blood were sampled during strictly standardized conditions during hypothyroid and euthyroid states. The patients were hospitalized for 5 days at a metabolic ward on a standardized sodium and potassium intake. On the fourth day catheters were positioned in the axillary artery and vein. Blood samples were drawn simultaneously for noradrenaline and adrenaline determinations during resting conditions. The arterial and venous plasma noradrenaline levels did not differ significantly, neither during hypothyroidism nor during euthyroidism. The arteriovenous difference in plasma adrenaline was similar during hypothyroidism compared to euthyroidism, indicating similar peripheral extraction rate of catecholamines during hypothyroidism as compared to euthyroidism. During hypothyroidism venous and arterial noradrenaline were significantly higher as compared to euthyroidism. In conclusion, there is no difference between arterial and venous noradrenaline levels either in the hypothyroid or the euthyroid state, and the peripheral extraction rate of plasma noradrenaline seems to be similar in hypothyroidism and euthyroidism. The local contribution of noradrenaline from the arm, reflecting local sympathetic nervous activity, is limited during resting conditions. In hypothyroid patients plasma noradrenaline levels are increased as compared to the euthyroid state, indicating increased general sympathetic activity in hypothyroidism.

The volume of trapped gas: a new and sensitive test for the detection of exercise-induced bronchospasm in children.

The volume of trapped gas (VTG) was measured at the end of a nitrogen multiple breath wash out procedure in 16 asthmatic and 10 healthy children before and after exercise. When compared to conventional spirometric variables VTG was the most sensitive test for detection of exercise-induced asthma (EIA). The VTG was significantly higher before exercise in the asthmatic children and increased significantly after exercise, while it did not change in the healthy controls. The significance of changes caused by EIA increased if VTG/TLC % or VTG/VC % wer used. Salbutamol inhalation normalized the VTG in all the asthmatic children.

Decreased blood pressure response to infused noradrenaline in normotensive as compared to hypertensive patients with primary hypothyroidism.

OBJECTIVE AND PATIENTS: To further explore the difference in plasma noradrenaline in normotensive and hypertensive hypothyroid patients we have investigated the pressor response to exogenous noradrenaline in 11 normotensive and five hypertensive patients with primary hypothyroidism before and after thyroxine replacement. Seven healthy subjects served as controls. DESIGN: The patients were studied under metabolic ward conditions and received a Na+ and K+ defined diet for 4 days. The controls received the same diet on an ambulatory basis for 3 days and were admitted to the ward in the evening on the third day. In the morning of day 4 a graded noradrenaline infusion was given. When the increase in systolic blood pressure in two consecutive registrations was at least 20 mmHg as compared to basal values the noradrenaline infusion was stopped. The dose required to increase systolic blood pressure by 20 mmHg (I20) was determined. RESULTS: During hypothyroidism the I20 was 120 ng/kg BW/min in normotensive patients and 39 in hypertensive patients as compared to 62 in controls. The I20 was higher in normotensives as compared to hypertensives (P = 0.041). The I20 was not different in hypertensives as compared to controls. When the patients had become euthyroid I20 decreased to 51 ng/kg BW/min (P = 0.04) in the normotensives, but remained unchanged in the hypertensives. There was no difference in I20 between normotensive and hypertensive patients in the euthyroid state, or when compared to controls. CONCLUSION: The pressor response to noradrenaline was decreased in normotensive hypothyroid as compared to hypertensive hypothyroid patients, indicating a decreased peripheral sensitivity to noradrenaline in normotensive hypothyroid patients. Following thyroxine replacement the decreased response became normal.