Pulmonary Artery Pressure Curves Research Articles

Inhibition of overexpressed Kv3.4 augments HPV in endotoxemic mice

BackgroundHypoxic pulmonary vasoconstriction (HPV) is a reaction of the pulmonary vasculature upon hypoxia, diverting blood flow into ventilated areas to preserve oxygenation. It is impaired in endotoxemia or ARDS. Voltage gated potassium channels have been shown to play a key role in the regulation of HPV. The aim of the study was to identify a voltage gated potassium channel involved in dysregulated HPV during endotoxemia.MethodsLungs of male C57BL/6 mice with and without endotoxemia (n = 6 ea. group) were analyzed for Kv3.4 gene and protein expression. HPV was examined in isolated perfused lungs of mice with and without endotoxemia and with and without selective Kv3.4 blocker BDS-I (n = 7 ea. group). Pulmonary artery pressure (PAP) and pressure-flow curves were measured during normoxic (FiO2 0.21) and hypoxic (FiO2 0.01) ventilation. HPV was quantified as the increase in perfusion pressure in response to hypoxia in percent of baseline perfusion pressure (ΔPAP) in the presence and absence of BDS-I.ResultsKv3.4 gene (3.2 ± 0.5-fold, p < 0.05) and protein (1.5 ± 0.1-fold p < 0.05) expression levels were increased in endotoxemic mouse lungs. Endotoxemia reduced HPV (∆PAP control: 121.2 ± 8.7% vs. LPS 19.5 ± 8.0%, means ± SEM) while inhibition of Kv3.4 with 50 nM BDS-I augmented HPV in endotoxemic but not in control lungs (∆PAP control BDS-I: 116.6 ± 16.0% vs. LPS BDS-I 84.4 ± 18.2%, means ± SEM).ConclusionsKv3.4 gene and protein expressions are increased in endotoxemic mouse lungs. Selective inhibition of Kv3.4 augments HPV in lungs of endotoxemic mice, but not in lungs of control mice.

Implementation and Calibration of a Deep Neural Network to Predict Parameters of Left Ventricular Systolic Function Based on Pulmonary and Systemic Arterial Pressure Signals.

The evaluation of cardiac contractility by the assessment of the ventricular systolic elastance function is clinically challenging and cannot be easily obtained at the bedside. In this work, we present a framework characterizing left ventricular systolic function from clinically readily available data, including systemic and pulmonary arterial pressure signals. We implemented and calibrated a deep neural network (DNN) consisting of a multi-layer perceptron with 4 fully connected hidden layers and with 16 neurons per layer, which was trained with data obtained from a lumped model of the cardiovascular system modeling different levels of cardiac function. The lumped model included a function of circulatory autoregulation from carotid baroreceptors in pulsatile conditions. Inputs for the DNN were systemic and pulmonary arterial pressure curves. Outputs from the DNN were parameters of the lumped model characterizing left ventricular systolic function, especially end-systolic elastance. The DNN adequately performed and accurately recovered the relevant hemodynamic parameters with a mean relative error of less than 2%. Therefore, our framework can easily provide complex physiological parameters of cardiac contractility, which could lead to the development of invaluable tools for the clinical evaluation of patients with severe cardiac dysfunction.

Effects of notoginseng and ginkgo leaf tablets on cardiac function and serum inflammatory factors in hypoxia deacclimatized rats and its mechanism

To study the effects of notoginseng, gingko leaf and rhodiola on cardiac functions and the serum inflammatory factors interleukin-6,interleukin-10, and TNF-α of rats with hypoxia deacclimatization, to explore the mechanism of hypoxia detoxification. Forty SD rats were randomly divided into notoginseng group(n=10), gingko leaf group(n=10), rhodiola group(n=10) and high altitude control group(n=10) after fed in a hypobaric hypoxia chamber(simulated altitude of 5 000 m) for 3 month, while 10 rats fed at normal pressure and oxygen environment for 3 month were used as the plain control group. Rats in notoginseng group, gingko leaf group and rhodiola group were treated with notoginseng, gingko leaf tablets or rhodiola suspension through intragastric administration (200 mg/kg,twice a day, for 10 days). After the rats got intraperitoneal anesthesia with 10% urethane, 5 min pulmonary artery pressure curve were traced continuously while pulmonary artery pressure (PAP). Left and right ventricular systolic pressure (VSP) and ventricular diastolic pressure (VEDP), the hemodynamic parameters were detected through a multi-channel physiological recorder. Serum tumor necrosis factor-α(TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. Right ventricular systolic pressure (RVSP), right ventricular end-diastolic pressure (RVEDP), mean pulmonary artery pressure (mPAP), left vent-ricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP),IL-6,and IL-10 were higher in notoginseng group, gingko leafgroup, rhodiola group and high altitude control group than those in plain control group(P＜0.05 or P＜0.01). The contents of MDA and TNF-α were higher while the level of SOD was lower in rhodiola group and high altitude control group than those in plain control group(P＜0.01). The contents of MDA and TNF-α were lower while the level of SOD was higher in notoginseng group, gingko leaf group and rhodiola group than those in high altitude control group(P＜0.01). The levels of RV,RVHI,RVSP,RVEDP,LVSP,LVEDP,IL-10 and TNF-α were statistically changed in notoginseng group than those in gingko leaf group and rhodiola group(P＜0.05orP＜0.01). Notoginseng, gingkoleaf and rhodiola can enhance antioxidant capacity of body and improve ventricular functions and Notoginseng, gingko leaf and rhodiola can effectively enhance the functions of ventricular and hypoxia tolerance and inhibit the expressions of inflammatory factors in rats during the hypoxia deacclimatization.

Role of ATP-sensitive potassium channels on hypoxic pulmonary vasoconstriction in endotoxemia

BackgroundATP-regulated potassium channels (KATP) regulate pulmonary vascular tone and are involved in hypoxic pulmonary vasoconstriction (HPV). In patients with inflammation like sepsis or ARDS, HPV is impaired, resulting in a ventilation-perfusion mismatch and hypoxia. Since increase of vascular KATP channel Kir6.1 has been reported in animal models of endotoxemia, we studied the expression and physiological effects of Kir6.1 in murine endotoxemic lungs. We hypothesized that inhibition of overexpressed Kir6.1 increases HPV in endotoxemia.MethodsMice (C57BL/6; n = 55) with (n = 27) and without (n = 28) endotoxemia (35 mg/kg LPS i.p. for 18 h) were analyzed for Kir6.1 gene as well as protein expression and HPV was examined in isolated perfused mouse lungs with and without selective inhibition of Kir6.1 with PNU-37883A. Pulmonary artery pressure (PAP) and pressure-flow curves during normoxic (FiO2 0.21) and hypoxic (FiO2 0.01) ventilation were obtained. HPV was quantified as the increase in perfusion pressure in response to hypoxic ventilation in mmHg of baseline perfusion pressure (ΔPAP) in the presence and absence of PNU-37883A.ResultsEndotoxemia increases pulmonary Kir6.1 gene (+ 2.8 ± 0.3-fold) and protein expression (+ 2.1 ± 0.3-fold). Hypoxia increases HPV in lungs of control animals, while endotoxemia decreases HPV (∆PAP control: 9.2 ± 0.9 mmHg vs. LPS: 3.0 ± 0.7 mmHg, p < 0.05, means ± SEM). Inhibition of Kir6.1 with 1 μM PNU-37883A increases HPV in endotoxemia, while not increasing HPV in controls (∆PAP PNU control: 9.3 ± 0.7 mmHg vs. PNU LPS: 8.3 ± 0.9 mmHg, p < 0.05, means ± SEM).ConclusionEndotoxemia increases pulmonary Kir6.1 gene and protein expression. Inhibition of Kir6.1 augments HPV in murine endotoxemic lungs.

Pressure‐Guided Cryoballoon Isolation of the Pulmonary Veins for the Treatment of Paroxysmal Atrial Fibrillation

Pulmonary vein (PV) isolation using a balloon-mounted cryoablation system is a new technology for the percutaneous treatment of atrial fibrillation (AF). Complete PV occlusion during balloon ablation has been shown to predict successful electrical isolation. The aim of this study was to correlate mechanical PV occlusion with changes in a pressure curve recorded at the distal tip of the cryoballoon catheter. We analyzed 51 PVs in 12 patients (61 +/- 6 years old) with paroxysmal AF. At first, PV occlusion via the cryoballoon was documented by changes in the pressure curve. Once the PV is occluded, the pressure curve registered in the vein converts from a left atrial pressure curve to a pulmonary artery pressure curve: the PV wedge curve. Occlusion was then confirmed by transesophageal echocardiography (TEE). Following 2 cryoablation applications, electrical PV isolation was assessed with a circumferential mapping catheter. Under the exclusive guidance of changes in the pressure curve at the tip of the cryoballoon, mechanical occlusion confirmed by TEE was achieved in 47 of 51 PVs (92%). Three PVs required further TEE guidance to achieve occlusion. All 50 occluded veins were electrically isolated after cryoablation. One right inferior vein, which could not be occluded with the balloon, displayed conduction post cryoablation and was isolated by focal ablation. Occlusion and electrical isolation of PVs during cryoballoon ablation can be predicted by the appearance of a PV wedge curve at the tip of the catheter. This new straightforward parameter may facilitate the procedure.

Effects of ketamine on hypoxic pulmonary vasoconstriction in the isolated perfused lungs of endotoxaemic mice

During sepsis and endotoxaemia, hypoxic pulmonary vasoconstriction (HPV) is impaired. Sedation of septic patients in ICUs is performed with various anaesthetics, most of which have pulmonary dilatory properties. Ketamine is a sympathetic nervous system-activating anaesthetic that preserves cardiovascular stability. The effects of ketamine on the pulmonary vasculature and HPV during sepsis have not been characterized yet. Therefore, isolated lungs of mice were perfused with ketamine (0, 0.1, 1.0, and 10 mg kg(-1) body weight min) 18 h following intraperitoneal injection of lipopolysaccharide (LPS); untreated mouse groups served as controls (n = 7 per group, respectively). Pulmonary artery pressure (PAP) and pressure-flow curves during normoxic (FiO(2) = 0.21) and hypoxic (FiO(2) = 0.01) ventilation were obtained. HPV was reduced in endotoxaemic animals when compared with controls (means +/- SD; DeltaPAP control 103 +/- 28% vs. LPS 23 +/- 25%, P < 0.05). Ketamine caused a dose-dependent reduction of HPV in the lungs of control (DeltaPAP 0 mg kg(-1) min(-1) ketamine 103 +/- 28% vs. 10 mg kg(-1) min(-1) ketamine 28 +/- 21%, P < 0.05) and septic animals (DeltaPAP 0 mg kg(-1) min(-1) ketamine 23 +/- 25% vs. 10 mg kg(-1) min(-1) ketamine 0 +/- 4%, P < 0.05). Analysis of pressure-flow curves revealed that ketamine partly reversed the endotoxin-induced changes in basal pulmonary vascular wall properties rather than interfering with the HPV response itself. Ketamine modified baseline pulmonary vascular properties, resulting in a reduced HPV responsiveness in untreated mice. Further, ketamine counteracted the LPS-induced changes in pulmonary vascular pressure-flow relationships, but did not affect impaired HPV in this murine endotoxaemia model.

Managing heart failure patients: when good-old-fashioned clinical care is not enough

Chronic heart failure (CHF) is the terminus of most other chronic cardiac diseases. For many patients, CHF is a dead-end road. In advanced stages of the disease, emphasis switches from...

Abstract 3278: Noninvasive Home Monitoring of Pulmonary Artery Pressure by the RemonCHF Device: First Multicenter Experience

Objectives: A reliable method for home monitoring of the pulmonary artery (PA) pressure might be useful to improve the management of patients with CHF. We describe the feasibility, safety and clinical utility of CHF monitoring using acoustic wireless communication with a miniature implant in the PA. Methods : Thirty-eight patients with NYHA class III-IV CHF (age 62.2±2.5 years) were included in a multicenter study. The device was implanted in the right PA using right heart catheterization in 33 suitable patients (due to instability of the implant it was retrieved after implantation in 2 patients). Ultrasonic energy was used for wireless communication and a complete PA pressure curve was recorded daily by patients using a simple, hand-held, home-unit. Home-unit for self monitoring was supplied to 25 patients. Seven patients underwent right heart catheterization at 6 months to assess long term accuracy of pressure measurement. Results : There were no major adverse events related to the implant / implantation procedure (follow-up duration 173±54 days). A total of 3094 home measurement were successfully performed by patients (mean±SD, 124±98). Compliance with daily monitoring was 93±16%. Pressure tracings at 6 months were almost identical to those obtained by Millar catheter (mean difference ± SD, 0.4±3.3mmHg). Variations of PA diastolic pressure were observed in relation to posture (sitting 5.5±4.0 mmHg lower than supine, p&lt;0.001), time of the day and medication schedule. Time trends of PA diastolic pressure documented improved hemodynamics following cardiac resynchronization therapy, detected pressure increase earlier than weight gain, and were helpful to adjust medical therapy. Two admissions for CHF decompensation were associated with a transient increase in PA pressure. Conclusions : Home monitoring of PA pressure using wireless acoustic communication with a miniature implant in the PA is feasible and safe. Patient’s compliance with self monitoring is very good, and reliable accurate data is easily obtained. Data demonstrated the physiological response to therapeutic interventions (medical and device). Daily monitoring might thus be helpful to optimize therapy of CHF, to improve quality of life and to prevent decompensations.

Patent Ductus Arteriosus

The patent ductus arteriosus (PDA) is a vascular structure that connects the proximal descending aorta to the roof of the main pulmonary artery near the origin of the left branch pulmonary artery. This essential fetal structure normally closes spontaneously after birth. After the first few weeks of life, persistence of ductal patency is abnormal. The physiological impact and clinical significance of the PDA depend largely on its size and the underlying cardiovascular status of the patient. The PDA may be “silent” (not evident clinically but diagnosed incidentally by echocardiography done for a different reason), small, moderate, or large. Regardless of the size, complications may arise, and it is important for both pediatric and adult cardiologists to have an understanding of the pathophysiology, clinical implications, and management of PDA. The ductus arteriosus is a normal and essential fetal structure that becomes abnormal if it remains patent after the neonatal period. In normal cardiovascular development, the proximal portions of the sixth pair of embryonic aortic arches persist as the proximal branch pulmonary arteries, and the distal portion of the left sixth arch persists as the ductus arteriosus, connecting the left pulmonary artery with the left dorsal aorta (Figure 1). Normally, the distal right sixth aortic arch loses its connection to the dorsal aorta and degenerates. This transformation is complete by 8 weeks of fetal life. Figure 1. Schematic of embryonic aortic arch system. The 6 pairs of embryonic aortic arches are demonstrated (left-sided arches are numbered). The portions that normally involute are indicated by broken lines. The distal left sixth embryonic arch normally persists and becomes the PDA, connecting the left pulmonary artery to the proximal descending aorta. The right distal sixth arch normally involutes, as does the eighth segment of the right dorsal aorta (*), which results in a leftward aortic …

Right Ventricular Systolic Function Is Not Depressed In Morbid Obesity

The increased pulmonary blood volume associated with the increased total blood volume in morbidly obese patients increases pulmonary artery pressure and pulmonary vascular resistance, resulting in increased right ventricular (RV) afterload. Thus, the morbidly obese may develop RV dysfunction owing to the increased RV afterload. We examined this possibility by assessing RV contractile function in morbidly obese patients, using RV end-systolic pressure-volume relationship and RV systolic time intervals. Included were 25 morbidly obese patients undergoing gastric bypass surgery under general anesthesia. Pulmonary artery pressure and RV end-systolic volume were measured with a thermodilution pulmonary artery catheter. Pulmonary arterial dicrotic notch pressure was used as an estimate of RV end-systolic pressure. Two data points were used to define RV end-systolic pressure-volume relationship. RV systolic time intervals were determined by simultaneous graphic display of the electrocardiograph, phonocardiograph, and pulmonary artery pressure curve, and were expressed as a pre-ejection period/RV ejection time ratio. The mean slope of right ventricular end-systolic pressure-volume relationship line was 0.54 +/- 0.13 and mean pulmonary vascular resistance 274 +/- 80 dyne.sec.cm(-5).m(-2). The mean pre-ejection period/RV ejection time ratio was 0.4 +/- 0.11. There was an inverse correlation between the pre-ejection/RV ejection time ratio and the slope of RV end-systolic pressure-volume relationship line (R(2)=0.658, P<0.0001). Our data indicate that RV function is not depressed in morbid obesity despite increased RV afterload.

Comparative In Vitro Study of Bileaflet and Tilting Disk Valve Behavior in the Pulmonary Position

A study of mechanical heart valve behavior in the pulmonary position as a function of pulmonary vascular resistance is reported for the St. Jude Medical bileaflet (SJMB) valve and the MedicalCV Omnicarbon (OTD) tilting disk valve. Tests were conducted in a pulmonic mock circulatory system and impedance was varied in terms of system pulmonary vascular resistance (PVR). An impedance spectrum was found using instantaneous pulmonary artery pressure and flow rate curves. Both valves fully opened and closed at and above a nominal PVR of 3.0 mmHg/L/min. The SJMB valve was prone to leaflet bounce at closure, but otherwise completely closed, at settings above and below this nominal setting. At PVR values at and below 2.0 mmHg/L/min, the SJMB valve exhibited two types of leaflet aberrant behavior: single leaflet only closure while the other leaflet fluttered, and incomplete closure where both leaflets flutter but neither remain fully closed. The OTD valve fully opened and closed to a PVR value of 1.6 mmHg/L/min. At lower values, the valve did not close. Valves designed for the left heart can show aberrant behavior under normal conditions as pulmonary valves.

High cardiac output by a continuous cardiac output pulmonary artery catheter

A 60-YEAR-OLD man with an orthotopic heart transplantation 7 months previously for congestive cardiomyopathy developed histologically proven acute transplant rejection and was admitted to the intensive care unit. Initially, he was hemodynamically stable while receiving dobutamine and nitroglycerin. After several days of reinforced immunosuppression, however, he developed pneumonia and septic shock. An intraaortic balloon pump was inserted by the cardiac surgeons to improve myocardial perfusion and function. In parallel, a continuous cardiac output (CO)–measuring pulmonary artery catheter was advanced via the internal right jugular vein. Continuous pressure recordings showed correct passage through the superior vena cava, right ventricle, and pulmonary artery. The pulmonary artery pressure curve was obtained after 60 cm, and the catheter was advanced further to 80 cm in an attempt to obtain a wedge pressure tracing, which, however, remained unsuccessful. A mixed venous blood sample was taken and revealed an oxygen saturation of 73%. During fixation of the catheter, measurement of continuous CO was started. Over the first sampling minutes, CO values of about 20 L/min were obtained (Fig 1). What is the diagnosis? From the Department of Anesthesiology and Intensive Care Medicine, Friedrich-Schiller-University of Jena, Jena, Federal Republic of Germany. Address reprint requests to Samir G. Sakka, MD, DEAA, Department of Anesthesiology and Intensive Care Medicine, Friedrich-SchillerUniversity of Jena, Bachstrasse 18, D-077433 Jena, Federal Republic of Germany. E-mail: Samir.Sakka@med.uni-jena.de Copyright 2002, Elsevier Science (USA). All rights reserved. 1053-0770/02/1606-0022$35.00/0 doi:10.1053/jcan.2002.128430

Assessment of right ventricular function by right ventricular systolic time intervals in acute respiratory failure.

Whether right ventricular systolic time intervals accurately reflect right ventricular function in patients with acute respiratory failure was determined by assessing the correlation between right ventricular systolic time intervals and the right ventricular end-systolic pressure-volume relationship. A prospective study. A surgical intensive care unit in a university hospital. Twenty patients with acute respiratory failure. Right ventricular systolic time intervals were determined by the simultaneous graphic display of the electrocardiogram, the phonocardiogram, and the pulmonary artery pressure curve and were expressed as a ratio of the pre-ejection period/right ventricular ejection time. The total electromechanical systole was measured from the onset of the electrocardiographic wave complex to the pulmonic component of the second heart sound. Right ventricular ejection time was measured from the rapid upstroke of the pulmonary artery pressure curve to the dicrotic notch. Right ventricular ejection fraction, from which right ventricular end-systolic volume was derived, was measured by the thermodilution technique. Pulmonary artery dicrotic notch pressure was used as an estimate of right ventricular end-systolic pressure. Data were collected at the baseline and after one or two alterations in preload, to define the right ventricular end-systolic pressure-volume relationship line. There was an inverse correlation between the pre-ejection period/right ventricular ejection time ratio and the slope of the right ventricular end-systolic pressure-volume relationship line (r2 = .67; p < .0001). When patients were divided into two groups, based on the pre-ejection period/right ventricular ejection time ratio, the slope of the right ventricular end-systolic pressure-volume relationship line was lower in the group with a high pre-ejection period/right ventricular ejection time ratio (p < .0001). No difference in other hemodynamic data, between the two groups, was noted. These data suggest that right ventricular systolic time intervals reflect right ventricular performance accurately in patients with acute respiratory failure.

Doppler derivation of complete pulmonary artery pressure curves in patent ductus arteriosus

In this study, we have demonstrated a method of obtaining complete, accurate PA pressure curves from a PDA Doppler flow velocity signal and a simultaneous aortic pressure tracing. This technique provides a dynamic evaluation of changes in PA pressures throughout the cardiac cycle and provides more hemodynamic information than single-point Doppler velocity methods of estimating PA pressures.

Spectral analysis of cyclic fluctuations in haemodynamic parameters in critically ill patients.

In critically ill patients haemodynamic parameters are being routinely monitored. All of the fluctuations in blood pressures cannot be visualised since on most monitors the time window is too short and trend curves do not have a sufficient time resolution. Therefore, frequency analysis was applied to an 800-second window. Systemic artery pressure, central venous pressure and pulmonary artery pressure curves of 6 patients were sampled with a frequency of 40 Hz. The signals were transformed into the frequency domain by the Fast Fourier Transform method. Bispectral analysis was applied to determine the origin of higher frequencies. There were three main frequencies present: heart stroke rate, respiratory frequency and a slow frequency (< 0.05 Hz), which was equal to the used infusion rate (2-10 ml/h) of vaso-active drugs. Continuous infusion of short-acting vaso-active drugs delivered by pulsatile diaphragm pumps to produce slow significant fluctuations in especially the arterial blood pressures (range: 5-40 mmHg). The periodicity of these slow fluctuations is not visualised during routine monitoring, so the observer may misinterpret the cause of changes in blood pressure and make inappropriate clinical decisions. A solution for detection of such slow waves is Fast Fourier Transform combined with bispectral analysis.

Feasibility of generating hemodynamic pressure curves from noninvasive Doppler echocardiographic signals

Objectives. This study was designed to determine the feasibility of Doppler generation of accurate, complete right ventricular and pulmonary artery pressure curves in patients with Dopplermeasurable tricuspid and pulmonary regurgitation.Background. Doppler-derived flow velocities have been used to assess right ventricular systolic pressure; pulmonary artery systolic, diastolic and mean pressures, and left ventricular systolic and diastolic pressures. Instantaneous gradient across any area of discrete narrowing is accurately derived using the simplified Bernoulli equation (4V2). Invasive catheterization is currently the only means of generating intracardiac pressure curves. Noninvasively derived pressure curves using Doppler echocardiography would be a considerable advance in the assessment of normal and pathologic cardiac hemodynamics.Methods. Right ventricular and pulmonary artery pressure curves were generated in 18 of 22 patients with measurable tricuspid and pulmonary valve regurgitation using superimposition of Doppler-measured tricuspid and pulmonary valve blood flow velocities on an assumed right atrial pressure. Dopplermeasured right ventricular and pulmonary artery pressure curves were compared with simultaneous catheterization-measured curves.Results. Doppler-derived pulmonary artery systolic pressure (Doppler PAP) correlated with simultaneous catheter-measured pulmonary artery pressure (Cath PAP) by the equation Doppler PAP = 0.92(Cath PAP) + 4.5, r = 0.98. Other Doppler-derived pressure measurements that correlated at near identity with the catheterization-measured corresponding measurement include Doppler-derived pulmonary artery mean pressure (Doppler mean PAP) [Doppler mean PAP = 0.85(Cath mean PAP) + 2.6, r = 0.97], and Doppler-derived right ventricular pressure (Doppler RVP) [Doppler RVP = 0.84(Cath measured RVP) + 7.9, r = 0.98]. Doppler-derived pulmonary artery diastolic pressure (Doppler PAP diast) did not correspond as well in this study [Doppler PAP diast = 0.45(Cath PAP diast) + 6.6, r = 0.83].Conclusions. Clinically usable right ventricular and pulmonary artery pressure curves can be derived by superimposing Dopplermeasured tricuspid and pulmonary valve blood flow velocities in patients with tricuspid and pulmonary valve regurgitation.

37 Doppler derived complete pulmonary artery pressure curves from a patient ductus arteriosus

37 Doppler derived complete pulmonary artery pressure curves from a patient ductus arteriosus

Right ventricular systolic time intervals determined by means of a pulmonary artery catheter.

To evaluate the right ventricular systolic time interval as an index of right ventricular function and also to ascertain whether the right ventricular ejection fraction may be determined by means of a conventional pulmonary artery catheter. Prospective study. Intensive care unit. Eight, consecutive critically ill adult patients. Simultaneous blind measurements, performed by two investigators, of the right ventricular systolic time interval and right ventricular ejection fraction, determined by means of a pulmonary artery catheter. Two studies, separated by an interval of 24 hrs, per patient. Linear regression analysis. Multiple regression test. Of the 16 studies performed, two determinations of right ventricular systolic time intervals were technically inadequate. In the remaining 14 valid studies, we found one close linear correlation between the right ventricular ejection fraction and the preejection period/ejection time quotient measured using the simultaneous display of the electrocardiogram (EKG) and pulmonary arterial pressure curve (r2 = .90, p < .001, right ventricular ejection fraction = 68.96-60.59 x [right ventricular preejection period/right ventricular ejection time]). The method proved to be simple, very accurate, with little interobserver variation (8.09 +/- 10.6% interobserver variation for right ventricular preejection period/right ventricular ejection time) and provided adequate information regarding situations in which the performance of the right ventricle is modified in a given patient. The right ventricular preejection period/right ventricular ejection time quotient was the only variable that displayed a significant relationship with the right ventricular ejection fraction in the multivariate analysis (p < .001). Right ventricular systolic time intervals, measured using the simultaneous display of the pulmonary artery catheter curve and EKG, provide adequate information regarding right ventricle performance in critically ill patients. The close linear correlation between the right ventricular preejection period/right ventricular ejection time quotient and the right ventricular ejection fraction enables the investigator to estimate, with a high degree of accuracy, the right ventricular ejection fraction and the values derived from the preload of the right ventricle, without the need for a modified pulmonary artery catheter.

Cathétérisme de l'artère pulmonaire par abord percutané de la veine axillaire

The choice of venous access can be difficult in patients under intensive care. The axillary vein appeared interesting to evaluate. This prospective study involved 63 punctures carried out in 59 patients during a 16 month period (14 females and 45 males; mean age : 54±4 yr). 34 patients were tracheostomized and under controlled respiration; some had coagulation abnormalities (8 cases). The other 29 patients were undergoing a preoperative haemodynamic study. Puncture of the axillary vein was carried out with the needle inserted at an angle of 30° to the skin surface and directed parallel to the artery medial to its course. The Seldinger technique was used (catheter and guide wire). Overall success rate was 87.5 %. In 73 %, less than three attempts were required. After the catheter was set in place in the axillary vein, the mean time required to reach the pulmonary artery was 7±15 min (range : 20 s-45 min). Less than 1 min was needed in 60 %. Extrasystoles were observed in 3.6 %. The incidence of arterial puncture was 11 % without any late complications. In every case, pulmonary artery and capillary wedge pressure curves were obtained, as well as cardiac output measurements. Mean duration of catheterization was 2±1.1 days in the preoperative haemodynamic group and 4±1.7 days in the other. No infectious complication was related to the catheterization. One thrombosis of the axillary and suclavian veins was noted (1.8 %). The axillary vein appeared therefore to be useful for pulmonary artery catheterization. It is an alternative choice in patients under controlled ventilation and with coagulation problems.

Wall motion characteristic of the right pulmonary artery in the suprasternal echocardiogram

This study describes the motion pattern of the right pulmonary artery (RPA) as it can be assessed from the suprasternal echocardiogram. The motion characteristic of the RPA is dependent on hemodynamic factors within the lumen of the RPA and those within the left atrium and the aortic arch. During atrial contraction the superior wall of the left atrium separates from the inferior wall of the RPA (IWRPA) and produces an "a" dip in the wall motion of the IWRPA. During isovolumic contraction the RPA is shifted upward (IC point). The incisura in the pulmonary artery pressure curve reflecting pulmonic valve closure can be seen by a sudden decrease in the diameter of the RPA (PC point). In conditions coinciding with pulmonary arterial hypertension, the overall diameter of the RPA increases, and the IC and PC points are flattened or even absent. Thus, changes in hemodynamics caused by pulmonary or cardiac disease may be analyzed noninvasively on the basis of altered wall motion of the RPA.