Cardiocirculatory System Research Articles

Strain specific differences in a cardio-pulmonary resuscitation rat model

An asphyxial cardiac arrest rat model, originally developed for Sprague–Dawley rats, was transferred to a Wistar rat model. Several strain specific life support adjustments, i.e. ventilator settings, anaesthesia, and drug requirements, were necessary to stabilize the model for Wistar rats. Despite these arrangements numerous resuscitation related variables appeared different. Three groups were evaluated and compared: a temperature monitored Wistar group 1 ( n=34), a temperature controlled Wistar group 2 ( n=26) and a temperature controlled Sprague–Dawley group 3 ( n=7). Overall, Wistar rats seem to have more sensitive cardio-circulatory system evidenced by a more rapid development of cardiac arrest (164 vs. 201 s), requiring higher adrenaline/epinephrine doses (10 vs. 5 μg/kg) and requiring more time for recovery after resuscitation (i.e. for return of blood pressure and blood gases). Without strict temperature control (as in groups 2+3 rats) group 1 rats went into spontaneous mild to moderate hypothermia during the first 24 h after restoration of spontaneous circulation (ROSC). Spontaneous hypothermia delayed the development of overall visible CA1 neuronal damage 24–48 h, but did not prevent it; therefore the model seemed to be suitable for future studies. Neuronal damages in the CA1 region in Wistar rats appeared to be more as shrunken cell bodies and pyknotic nuclei before resorption took place, whereas in Sprague–Dawley rats appeared in the same region.

Serotonin localization in Phallusia mammillata larvae and effects of 5-HT antagonists during larval development.

The neurotransmitter 5-hydroxytryptamine (5-HT, serotonin) plays an important role in a wide range of non-neural processes. Using immunofluorescence with an antiserotonin antibody, 5-HT was localized in the brain and in some neurons of the larval tail of Phallusia mammillata. To test the effect of 5-HT on development, we treated embryos with two different 5-HT receptor subtype antagonists. Treatment at the gastrula stage with 10 microM ondansetron, an antagonist of the 5-HT(3) receptor, induced anterior truncation and a short tail. At 10 microM, ritanserin, a 5-HT(2B) receptor antagonist, induced larval phenotypes characterized by a roundish trunk region with flat papillae. The juveniles developed from these larvae had an abnormal cardiocirculatory system: their heart contractions were ineffective and their blood cells accumulated in the heart cavity. We conclude that an appropriate level of 5-HT is necessary for correct development and morphogenesis. Moreover, a different key role for multiple receptors in modulating the morphogenetic effects of 5-HT is suggested.

Liberação de pressão de vias aéreas em pacientes pediátricos submetidos à cirurgia cardíaca

Comparison of three modes of MV: intermittent mandatory ventilation with positive end expiratory pressure (IMV + PEEP), APRV and continuous positive airway pressure (CPAP) in children during cardiac surgery post operative with pulmonary hypertension and mild or moderate pulmonary lesion. Ten patients were studied with respiratory monitoring (Bear Neonatal Volume Monitor-1) in MV with a continuous flow, time cycled and pressure limited ventilator. The cardiocirculatory variables analyzed were central venous pressure (CVP), oxygen extraction ratio, cardiac rate, systolic arterial pressure, and arterial-mixed venous CO2 difference. Friedman's test (nonparametric) was used to compare the variables in three modalities of ventilation and the Wilcoxon test was used for the variables obtained in two of the modalities. The mean airway pressure (MAP) showed a significant increasing during APRV compared to IMV + PEEP (p = 0.012). The positive inspiratory pressure (PIP), the minute volume and the ratio of oxygen arterial pressure to oxygen inspired fraction (PaO2/FiO2) didn't show statistical difference. During APRV there was a significant decrease in respiratory rate (p = 0.004) and an increase in tidal volume (p = 0.045) when compared to CPAP and IMV + PEEP. In the cardiocirculatory system only CVP showed a significant increased (p = 0.019) during APRV. Due to the methodology utilized MAP was higher with APRV resulting in an increased tidal volume without respiratory or cardiocirculatory adverse effects when the three modes were compared. Our results suggest that APRV is a simple and safe method of ventilation.

Clinical significance and effects of foreign body embolism during the use of central venous catheters

An embolism caused by catheters or puncture devices is generally a rare complication during the use of central venous catheters. Possible reasons are either mistakes on the part of the user (e.g. shearing off or tearing of catheters or Seldinger wires) or other accidental causes (e.g. faulty products, material fatigue). As patients are at risk of suffering serious injuries following an embolism, foreign bodies should be removed from the patient's cardio circulatory system as quickly and as completely as possible. Two-dimensional echo-cardiography has proved to be very helpful for diagnostics, while interventional radiology is most effective for the removal of intravascular foreign bodies.

NEUROMUSCULAR BLOCKADE AND INTUBATION CONDITIONS OF THE SINGLE BOLUS DOSE (2xED90) OF ROCURONIUM BROMIDE

Rocuronium bromide (2xED90), a new non depolarising neuromuscular blocking drug with rapid onset, intermediate duration of action and cardiostability was studied in open randomised trial in 30 patients. Neuromuscular block was monitored using a Train of Four stimulus by stimulator electrodes placed on the ulnar never close to the wrist. Intubation conditions were assessed subjectively by scoring the jaw relaxation, vocal cord and the response to intubation with same technique of anaesthesia. Clinical recovery (Dur25) of neuromuscular blockade was monitored. Haemodynamic changes were recorded. Intubation conditions were clinically acceptable in 99.6% of patients, (excellent 73%; good 26.6%) at 90s. Time to onset (Lag time) of neuromuscular block was 22.5 ± 12.6 sec and average time for the onset of block (maximum effect) was 90.9 ±10.6 sec. The duration of clinical muscular relaxation (25% recovery of twitch height) was 22.4 ± 8.30 min. Stability of cardiocirculatory system was seen.

Transient oxygen uptake response to exercise characterizes functional capacity of the cardiocirculatory system in patients with chronic heart failure: a random stimulus approach.

The transient response of oxygen uptake (VO2) to submaximal exercise, known to be abnormal in patients with cardiovascular disorders, can be useful in assessing the functional status of the cardiocirculatory system, however, a method for evaluating it accurately has not yet been established. As an alternative approach to the conventional test at constant exercise intensity, we applied a random stimulus technique that has been shown to provide relatively noise immune responses of system being investigated. In 27 patients with heart failure and 24 age-matched control subjects, we imposed cycle exercise at 50 W intermittently according to a pseudo-random binary (exercise-rest) sequence, while measuring breath-by-breath VO2. After determining the transfer function relating exercise intensity (W) to VO2 and attenuating the high frequency ranges (> 6 exercise-rest cycles x min(-1)), we computed the high resolution band-limited (0-6 cycles x min(-1)) VO2 response (0-120 s) to a hypothetical step exercise. The VO2 response showed a longer time constant in the patients than in the control subjects [47 (SD 37) and 31 (SD 8) s, respectively, P < 0.05]. Furthermore, the amplitude of the VO2 response after the initial response was shown to be significantly smaller in the patients than in the control subjects [176 (SD 50) and 267 (SD 54) ml x min(-1) at 120 s]. The average amplitude over 120 s correlated well with peak VO2 (r = 0.73) and deltaVO2/deltaW (r = 0.70), both of which are well-established indexes of exercise tolerance. The data indicated that our band-limited VO2 step response using random exercise was more markedly attenuated and delayed in the patients with heart failure than in the normal controls and that it could be useful in quantifying the overall functional status of the cardiocirculatory system.

Évaluation préopératoire de la circulation coronarienne

To define a strategy for coronary circulation assessment is a difficult task as most of the studies have been carried out in vascular surgery, as some of them are controversial, and as no test has a 100% sensitivity and specificity. However patients with high perioperative risk of cardiac events have to be identified, in order to intensify medical treatment or to consider myocardial revascularisation. A first evaluation is based on history, physical examination and simple tests, such as rest electrocardiogram and thorax X-Ray. Additional tests are not required when surgery does not elicit a major activity of the cardiocirculatory system. Postoperative cardiac risk is low when none of the nine risk factors defined by Goldman and/or coronary insufficiency (residual angina elicited by minor physical activity, unstable angina, myocardial infarction) are present. The problem remains in patients with Goldman risk factors and/or at risk of coronary artery disease because of diabetes mellitus, heavy smoking, hypercholesterolaemia, arterial hypertension, undergoing major abdominal, thoracic or vascular surgery. Preoperative electrocardiographic Holter monitoring is still of value, especially in patients with known or supposed ischaemic heart disease and unable to make a physical effort. A poor exercise capacity and changes in electrocardiographic stress testing are factors of poor prognosis. The dobutamine stress echocardiography has a good sensitivity and specifity when an effort test cannot be performed. The value of dipyridamole-thallium 201 scintigraphy could be improved by a quantitative analysis of the number of affected segments and territories. Patients with angina or ischaemic episodes on continuous electrocardiogram, or with dobutamine echocardiography kinetic disturbances and with stress myocardic scintigraphy or stress exercise testing abnormalities could undergo a coronarography, in order to consider myocardic revascularization prior to surgery.

Haemodynamics during sleep: old results and new perspectives.

After the advent of polygraphic recordings in the 1960s a great deal of interest focused on cardiocirculatory and respiratory activity during sleep. The Bologna sleep laboratory was the first to make direct recordings of systemic arterial pressure, pulmonary arterial pressure and alveolar ventilation in normal subjects, measuring gas-blood values during different sleep stages. In the 1960s, neurophysiologists rediscovered a syndrome known to pneumologists for a decade as Pickwickian Syndrome. Polygraphic studies performed in sleep laboratoires all over Europe (Germany, France and Italy) led to a major discovery: the syndrome was not caused by respiratory overload due to obesity, but usually by the presence of obstructive apnoeas arising during sleep. By means of continuous sleep recordings, our laboratory documented the severe repercussions of apnoeas on ventilatory and cardiocirculatory functions. Hypnologists pointed to tracheostomy as the logical effective treatment for the syndrome. Surgery was first performed in Germany by Kuhlo and coworkers and then in Bologna. In the early 1970s, following the Bologna group's research, there emerged the now accepted concept that obstruction of the upper airways is a continuum stretching from snoring to full-blown sleep apnoea syndrome. The Bologna team was also the first to conduct epidemiological surveys that indicated that snoring is a relevant risk factor for the cardiocirculatory system. Here the trends of haemodynamic and ventilatory parameters during sleep are investigated in syndromes of obstructive respiratory failure. The conclusion is that sleep, particularly REM-sleep, exacerbates all these disorders, and the topic provides a basis for a wider look at how cardiocirculatory activity varies during sleep under normal and pathological conditions.

Applied potential tomography shows differential changes in fluid content of leg tissue layers in microgravity

Absence of hydrostatic forces in the human cardiocirculatory system normally leads to an overall body fluid deficit. It was hypothesized that this is mainly due to a loss of interstitial fluid. An experiment was performed on board the Russian MIR station. Cuffs were positioned around both thighs and inflated up to suprasystolic values. This maneuver took place just before and after immediately a lower body negative pressure session (LBNP). The redistribution of fluids underneath the cuffs was assessed by means of cross-sectional impedance tomography (Applied Potential Tomography, APT). A μ- g induced loss of interstitial fluid was measured in all layers of the observed cross-section. The APT-readings changed significantly (SD≈±.9) from 3.0 at 1 g to 1.7 at 0 g for the outer layer and from 2.7 at 1 g to 2.0 at 0 g for the middle layer (expressed in arbitrary units). The LBNP maneuver was able to fill the interstitial space but only at levels higher than - 15 mmHg LBNP. This suggests that the superficial tissues in the legs are as much affected as the deeper ones by changing g-conditions and LBNP can be used to counteract interstitial fluid loss in this area.

Exercise limitations in patients with pulmonary diseases.

An adequate analysis of the pathophysiology of the disease and of its ensuing type and degree of limitations is essential for evaluating the abilities for physical performance in patients with pulmonary diseases. Maximal exercise testing is an indispensable diagnostic tool in this respect. In light of moderate obstructive disease (FEV1 > approximately 60% pred), the exercise limitation comes from the cardio-circulatory system and/or peripheral muscle function. A rehabilitation program for these patients can be based on endurance training at high heart rate levels. Patients with a ventilatory limitation (FEV1 < 40%-60% pred.) show a failure of the respiratory pump, resulting in hypercapnia during exercise. Rehabilitation treatment will contain ergonomics, exercises for mobility and agility, breathing exercises with low-frequency breathing, relaxation exercises, and inspiratory muscle training. An oxygen-uptake limitation can be found in patients with a diffusion problem, severe ventilation-perfusion mismatch, or a reduced contact time between blood and alveolar gas. Such problems can often be seen in emphysema, and express themselves as isolated hypoxaemia during exercise. These patients benefit from a program consisting of ergonomics, exercises for mobilising the thoracic wall, low-frequency breathing, and exercising with additional oxygen. Many patients with chronic obstructive pulmonary disease (COPD) are limited for psychosocial reasons. The dyspnea is a negatively rewarding side effect of exercise in these patients. They tend to avoid all exertion, and thus get into a vicious circle of inactivity, low fitness, and unpleasant sensations during exercise. The inactivity often is also induced by the patient's family, since a 'patient-role' requires a quiet lifestyle.

Organ blood flow and microcirculation during inhalation anaesthetics

Summary Halogenated anaesthetics influence smooth muscle tone and thereby the microcirculation by two distinct mechanisms: (1) via reduced responsiveness to adrenergic sympathetic nervous outflow and decreased responsiveness of the cardiocirculatory system to adrenergic stimuli; and (2) via a direct (in the great majority of organ beds) relaxing effect on arteriolar resistance vessels. Besides negative inotropic effects on the heart, the anaesthetics can reduce cardiac output by dilation of venular segments and small veins and hence by a decreased return of blood to the heart. In terms of organ perfusion, the halogenated anaesthetics: (i) induce relative overperfusion, i.e. oxygen supply in excess of oxygen demand in heart and brain; (ii) do not grossly interfere with renal blood flow; but (iii) may profoundly impair hepatic perfusion. Thereby, halothane, enflurane and isoflurane exert different changes in organ blood flow. Halothane is the most potent cerebral vasodilator and isoflurane the least; the contrary applies for the heart and the hepatic arterial circulation. The actions of the new anaesthetic agents sevoflurane and desflurane resemble those of enflurane and isoflurane.

A modular numerical model of the cardiovascular system for studying and training in the field of cardiovascular physiopathology

A modular numerical model of the cardiovascular system has been developed to reproduce the most important circulatory phenomena in terms of pressure and volume relationships. It is an easy tool to use, designed to be used with a friendly approach on any IBM or compatible personal computer: it offers a wide selection of graphical and numerical outputs and can be rearranged easily for a particular experiment. A set of subroutines related to different circulatory phenomena has been developed; they can be assembled easily together and communicate with each other by two variables. A full description of the existing subroutines is presented in this paper with three different application examples resulting from the rearrangement of the existing software modules: the first concerns the behaviour of natural ventricle model itself and can be regarded as a ventricle stand-alone characterization test in terms of preload and afterload sensitivities, the second is related to the use of a pneumatic ventricle instead of the model of the natural ventricle, and the third is a full model of the cardiocirculatory system.

Sleep-related respiratory disorders.

Sleep-induced narrowing of the upper airways underlies the widespread and supposedly trivial complaint of snoring, which may not only constitute a risk factor for the cardiocirculatory system, but in predisposed individuals may lead to the OSAS. The latter is a life-threatening condition characterized by repeated episodes of cessation of respiration at night with an associated drop in SaO2. Patients frequently present with hypersomnia, systemic and pulmonary hypertension, and even heart failure. HSD is the term we use to describe the evolutive stages from snoring to OSAS. ICAH, or Ondine's curse, is the clinical syndrome of sleep-related respiratory insufficiency in the absence of airway stenosis. We do not consider central sleep apnea to be an independent disorder. For the treatment of HSD, weight reduction should be attempted first. Also, if there are malformations in the upper airway, they should be surgically corrected. The use of various medications has been rather discouraging, and CPAP and other devices that are intended to overcome the obstruction are poorly tolerated by patients. The most effective surgical treatment for OSAS, even in progressed stages of the disease, is tracheostomy.

Sleep-related respiratory disorders.

Neurologists are becoming increasingly aware of the frequency and clinical importance of sleep-related respiratory impairment. Sleep-induced narrowing of the upper airways underlies the widespread and supposedly trivial complaint of snoring, which may not only constitute a risk factor for the cardiocirculatory system, but in predisposed individuals, may lead to a sleep apnea syndrome, with its array of serious disturbances, including hypersomnia, systemic and pulmonary hypertension and ultimately heart failure. Idiopathic chronic alveolar hypoventilation, or Ondine's curse, is a fairly stereotyped clinical syndrome: sleep-related respiratory insufficiency in the absence of airways stenosis. Finally, sleep, and REM sleep in particular, significantly aggravates hypoventilation in patients with chronic obstructive pulmonary disease (COPD), kyphoscoliosis or chest musculoskeletal disorders.

Effects of simulated altitude on O 2 transport in dogs

The effects of exposure to simulated altitude on skeletal muscle and on the cardiocirculatory system have been studied on awake, conscious, dogs (16–39 kg) at rest and during moderate treadmill exercise at 15% incline. Measurements were obtained in Denver at a pb of 635 mm Hg and after 3 weeks of continuous exposure to a pb of 435 mm Hg using a hypobaric chamber. At both levels of pb the dogs showed marked panting, associated with pulmonary hyperventilation and low Pa CO 2 's (28 mm Hg at 635 and 17 mm Hg at 435 mm Hg). Resting V ̈ O 2 s were high (12.4 and 11.4 ml/min · kg) reflecting the high respiratory outputs. [Hb] and Hct increased significantly after 3 weeks at 435 mm Hg with a 4 mm Hg decrease in P 50. Q̈, HR, SV and systemic blood pressures were normal in both normoxic and hypoxic animals, at rest as well as during exercise. Arterial and mixed venous P O 2 's decreased in the hypoxic dogs (82 to 56 and 42 to 36 mm Hg, respectively) but arterial 0 2 content, arterial-venous 0 2 content difference and systemic 0 2 transport remained unchanged. Capillary density in the sternothyroid muscle doubled (617 to 1245 cap/mm2) after 3 weeks at a pb of 435, whereas the average muscle fiber diameter decreased about 30%. Calculations indicate that the P O 2 , in the ‘lethal corner’ of the muscle fiber is relatively higher in the hypoxic animal because of the decrease in fiber size and intercapillary distances.

Evaluation of physical performance by rectangular-triangular bicycle ergometry and computer-assisted ergospirometry.

A great deal of information about physical adjustment to work can be obtained from quantitative stress testing. Maximal stress limited by symptoms of exertional intolerance is the concept of the 2 min duration work increment test (rectangular-triangular exercise test). Compared to steady-state work tests strict observation of the standardized procedure- and computer assisted evaluation of ergospirometric parameters offer innovatory opportunities: (1) the test is of short duration (8-14 min), (2) the subjects recover rapidly, even from an exhausting test, (3) one is more likely to be able to observe plateauing of VO2, should determination of maximal VO2 be desired, (4) adaptation to increasing work rates and maximal work capacity is assessable, (5) computer technics provide on-line assessment of aerobic and anaerobic power in quantitative terms, (6) measurements proved to be highly reproducible, (7) the relationship between variables such as increments of heart rate and systolic blood pressure, respiratory minute volume, oxygen uptake during the early phase of the non-steady-state condition and the index of anaerobic power, and the influence of factors such as work load and work output, has been studied to derive standard values. Soft-ware programs have been designed to estimate deviation of parameters actually measured from standard values in terms of multiples of the standard deviation of the standard regression line. In particular, evaluating oxygen uptake during short time-intervals (0.5 min) provides information about adequate adaptational forces of the cardio-circulatory system. Energy that is not accounted for by reactions involving the VO2 measured is computed by substracting the caloric equivalent of oxygen uptake during work exceeding the steady-state level during rest from the energy demand to sustain a given work load aerobically. This index of anaerobic power is defined in kcal, cal/kg body wt., and as a percentage of the total amount of energy required (moderately trained athletes 350-500 cal/kg; sedentary people 200-300 cal/kg). A close relationship to parameters of metabolic acidosis (base excess) exists. It is concluded that the physical performance of sedentary people, athletes and patients with impaired cardio-pulmonary function can be more precisely qualified in quantitative terms by means of computer assisted rectangular-triangular ergospirometry. Results obtained in patients with diseased conditions must be carefully interpreted, their condition suggesting the use of more invasive investigations to reveal the pathophysiologic mechanism.

Antiarrhythmic effect of solvents: propylene glycol, benzyl alcohol.

Propylene glycol and benzyl alcohol, the main constituents of most solvent vehicles, display a pronounced antiarrhythmic-antifibrillatory effects, when injected intravenously into animals (dogs, rats) with spontaneous or drug-induced arrhythmias. The antiarrhythmic dose for propylene glycol amounts to 0.2-0.3 ml/kg of a 70 per cent solution and, for benzyl alcohol to 0.2-0.4 ml/kg of a 4 per cent solution in physiologic saline, respectively. Similar effects were also obtained by the combined injection of propylene glycol + benzyl alcohol, in proportions which correspond to the formulae of numerous commercial "solvents" (vehicles): 2 to 20 per cent solutions of benzyl alcohol in 70 per cent propylene glycol (0.05-0.2 ml/kg). The mechanisms which might be responsible for the antiarrhythmic activity of solvents are discussed: lengthening of the effective refractory period, local and general anaesthetic effects, changes of osmolarity. The intravenous injection of propylene glycol and/or benzyl alcohol, in high doses, produces intravascular haemolysis. Clinical investigations are recommended as to the potential, beneficial or toxic effects of drug solvents, especially upon the cardiocirculatory system.

Effect of nicotine on glyceraldehyde-3-phosphate deydrogenase and lactate/pyruvate ratio of arterial and venous coronary blood in dogs with restricted coronary circulation

Summary The pattern of response of glycoraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate/pyruvate ratio was studied in arterial and venous coronary blood, prior and after infusion of nicotine, in dogs with normal coronary circulation and dogs with coronary obstruction produced by Ameroid rings; at the same time, some of the hemodynamic characteristics of the cardiac activity were evaluated. In dogs with normal coronary circulation, nicotine infusion provokes in the coronary venous blood an increase in GAPDH and a significant increase in the lactate/pyruvate ratio. In animals with chronic ischemia, the nicotine infusion produces a small and inconstant increase in the GAPDH content of the coronary venous blood and no significant modifications in the lactate/pyruvate ratio. In the ischemic myocardium there is evidence of increase in the hexose monophosphate shunt, with decrease in the activity of the glycolytic enzymes and of the tricarboxylic cycle ( Gudbjarnason, et al, 1967 , Gudbjarnason, et al, 1968 , Gudbjarnason, et al, 1968 ). An observation of considerable interest is that the activation of the hexose monophosphate shunt occurs both in the ischemic zone and in that with normal oxygen supply. According to Gudbjarnason et al. (1967) this is explained by the fact that the energy requirements and, above all, the production of ribose-5-phosphate for the synthesis of the proteins necessary for cardiac hypertrophy, are supplied by this metabolic pathway. Glycernaldehyde-3-phosphate dehydrogenase (GAPDH) activity diminishes least among others enzimatic activities with decrease in the ischemic tissue ( Gudbjarnason, et al, 1968 , Gudbjarnason, et al, 1968 ). The importance of this enzyme in the carbohydrate and fat metabolism of the organism in general, and also for the myocardium, is well known: it plays a fundamental role in the activity of the embden-Mayeroff cycle and, indirectly, activates the cycle of the hexose monophosphate shunt in the ischemic tissue ( Gudbjarnason and Bing, 1971 ; Tschopp et al., 1968 ), allowing the conversion of the triose phosphates to acetyl-CoA, facilitating there by also the synthesis of fatty acids. Following up on a series of research initiated by one of us ( Corsini, et al, 1968 , Corsini, 1970 ), the behaviour of GAPDH, parallel with that of lactate/pyruvate ratio, was studied in the arterial and venous coronary blood, prior to and after infusion of nicotine, in dogs with normal coronary circulation, as well as in dogs with coronary circulation restricted by the application of Ameroid. Nicotine was chosen because of its known effects on the cardiocirculatory system (increase of heart rate, blood pressure, stroke volume and reduction in the coronary flow in presence of coronary insufficiency), and also on account of its action on carbohydrate and fat metabolism by stimulating such hormonal systems as the catecholamines and pitressin ( Goodman and Gilman, 1970 ).

The Effect of Xanthin Derivatives: Ro 1-8239, Aminophylline and Dihydroxy Theophylline on Chronic Pulmonary Disease

The widespread use of various xanthine derivates in chronic pulmonary disease have prompted numerous studies on the action of these drugs in both pulmonary function and cardiocirculatory system. It has been shown that aminophylline and dihydroxytheophylline (DHT) have bronchodilator properties”2 increasing ventilation by direct stimulation of the respiratory center.’ The object of the present study is to test the effect of various xanthinic compounds on the respiratory function of patients with chronic pulmonary disease, especially of the new compound Ro 1-8239 (X-D) .

Altered liver function of chronic congestive heart failure

C HRONIC congestive heart failure is characterized by widespread, complex and interrelated changes in various functions of the human body. That the liver is involved in these changes has been shown by numerous anatomic and physiologic studies.1-‘0 There is, however, little agreement among investigators as to the basic mechanisms producing the hepatic alterations. Anoxia, venous hypertension, malnutrition and infection, acting singly or in combination, have all been suggested as factors in the pathogenesis of the process. The possibility that the hepatic disturbance may secondarily modify the heart failure state remains a matter for speculation. In an attempt to appraise responsible mechanisms and possible functional interrelationships between the liver and the cardiocirculatory system, in patients with chronic congestive heart failure, a series of studies has been undertaken. The present report considers the nature and severity of liver impairment in the presence of cardiac decompensation and as compensation is restored. It also provides information concerning the role of venous pressure and arterial or hepatic hypoxia in determining or influencing the hepatic impairment.