[Quality of maternal mortality statistics in Cuba, 2013Qualidade das estatísticas de mortalidade materna em Cuba, 2013].

Objective: Evaluate the degree of integrity of the Cuban statistical registry of maternal deaths and the quality of the classification of the causes of death included in that registry.

Methods: We analyzed the information of all Cuban women who died in fertile age in 2013 according to the continuous mortality registry of the Directorate of Medical Records and Health Statistics of the Ministry of Public Health of Cuba (MINSAP), regardless of the main cause of death informed. Four research groups (national, expert, provincial and health units), each with defined functions, applied four forms to establish if the women had been pregnant in the year prior to death, to reassess whether the cases corresponded to a maternal death and, in that case, to review the classification.

[Maternal and child health care in Cuba: achievements and challengesCuidados de saúde materno-infantil em Cuba: conquistas e desafios].

In Cuba, maternal and child health care is based on the priority granted by the State, the implementation of the National Maternal and Child Health Program and the guarantee of equitable access to health services. This article describes the Cuban experience in this field, as well as its main achievements, challenges, and lessons learned. Among the most relevant results up to 2015 are the reduction of infant mortality rate and under-five mortality rate to 4.

The cardiac torsion as a sensitive index of heart pathology: A model study.

The torsional behaviour of the heart (i.e. the mutual rotation of the cardiac base and apex) was proved to be sensitive to alterations of some cardiovascular parameters, i.

Finite element analysis of the mechanical behavior of preterm lamb tracheal bifurcation during total liquid ventilation.

Knowledge of the mechanical behavior of immature airways is crucial to understand the effects exerted by ventilation treatments, namely by Total Liquid Ventilation (TLV). A computational approach was adopted to investigate preterm airways in the range of pressure applied during TLV. A 3D finite-element model of the tracheal bifurcation was developed.

Trends in biomedical engineering: focus on Patient Specific Modeling and Life Support Systems.

Over the last twenty years major advancements have taken place in the design of medical devices and personalized therapies. They have paralleled the impressive evolution of three-dimensional, non invasive, medical imaging techniques and have been continuously fuelled by increasing computing power and the emergence of novel and sophisticated software tools. This paper aims to showcase a number of major contributions to the advancements of modeling of surgical and interventional procedures and to the design of life support systems.

Experimental and computational biomechanical characterisation of the tracheo-bronchial tree of the bottlenose dolphin (Tursiops truncatus) during diving.

Dolphins have adapted their anatomic structures to survive in the water environment and so far, the behaviour of their respiratory system during diving has not been fully understood, since they being protected species cannot be subjected to invasive analysis. Aim of this work is to model the tracheo-bronchial tree of the bottlenose dolphin Tursiops truncatus to study its behaviour during diving by coupling experimental in vitro mechanical characterisation of airways tissues to finite element computational analyses. Furthermore, a comparison was performed between the mechanical behaviour of tracheo-bronchial trees of dolphins and that of the goat, a terrestrial mammal, whose conformation of the upper airways is similar to that of the human, to determine how different structures respond to pressure in a controlled experimental set-up.

Computational finite element model of cardiac torsion.

Purpose: A novel finite-element model of ventricular torsion for the analysis of the twisting behavior of the left human ventricle was developed, in order to investigate the influence of various biomechanical parameters on cardiac kinematics.

Methods: The ventricle was simulated as a thick-walled ellipsoid composed of nine concentric layers. Arrays of reinforcement bars were embedded in each layer to mimic physiological myocardial anisotropy.

A mechanical simulator of cardiac wall kinematics.

Aim of this study is to develop a mechanical simulator (MS) reproducing cardiac wall kinematics [i.e., radial (R), longitudinal (L) and rotational (RT) motions] to test piezoelectric gyroscopic sensors (GS) that are able to measure cardiac torsion that has proved to be a sensitive index of cardiac performance.

Preservation of endothelium nitric oxide release during beating heart surgery with respect to continuous flow cardiopulmonary bypass.

A correlation between perfusion modality and vascular dilation induced by endothelial nitric oxide (NO) release has been pointed out in the literature; nevertheless, only a few studies deal with the analysis of patients treated by cardiac surgery. The aim of this work is to analyze endothelial NO release in patients undergoing cardiac surgery under continuous flow cardiopulmonary bypass (CPB) or pulsatile perfusion. Pulsatile devices approved for clinical CPB do not accurately reproduce the physiological flow waveform provided by the left ventricle while, on the other hand, it is important to analyze pulsatile perfusion under both physiological flow waveform and pulsatile flow CPB.

Preservation of endothelium nitric oxide release by pulsatile flow cardiopulmonary bypass when compared with continuous flow.

The aim of this work is to analyze endothelium nitric oxide (NO) release in patients undergoing continuous or pulsatile flow cardiopulmonary bypass (CPB). Nine patients operated under continuous flow CPB, and nine patients on pulsatile flow CPB were enrolled. Plasma samples were withdrawn for the chemiluminescence detection of nitrite and nitrate.

Determination of cardiovascular mechanics evolution in the presence of the arteriovenous fistula.

Uremic patients are prone to heart damage as a consequence of arteriovenous fistula (AVF) presence and hemodialysis treatment. Arteriovenous fistula induces hand ischemic syndrome and cardiac work increase, thus determining cardiac insufficiency in the medium to long term. This work investigates the cardiovascular mechanics evolution induced by the fistula presence.

Integrated model of endothelial NO regulation and systemic circulation for the comparison between pulsatile and continuous perfusion.

Many experimental studies concerning nitric oxide (NO) release from endothelium and its vasodilative action are available in the literature, but no analytical description or modeling of these phenomena can be found. On the contrary, a large modeling literature is available concerning the other cardiovascular control mechanisms, such as the myogenic and metabolic control. In order to analytically describe these phenomena, a model of the endothelial control (defined in the Laplace domain and based on experimental data) was implemented and integrated with a lumped-parameter model of the systemic circulation, consisting of large artery segments and peripheral networks.

A new method to evaluate patient characteristic response to ultrafiltration during hemodialysis.

Background: Several factors are involved in the pathogenesis of dialysis discomfort interfering with optimal fluid removal and reducing the efficacy of the treatment; the most important one is a decrease in blood volume caused by an imbalance between ultrafiltration (UF) and plasmarefilling (PR) rates.

Objectives: This study is aimed at devising a method to tailor the dialysis therapy to each individual patient, by analyzing the relationship between PR and UF during the sessions in stable patients and widening the knowledge of fluid exchanges during the treatment.

Methods: Thirty stable patients undergoing maintenance hemodialysis were enrolled.

Effect of right ventricular pacing on cardiac apex rotation assessed by a gyroscopic sensor.

To quantify cardiac apex rotation (CAR), the authors recently proposed the use of a Coriolis force sensor (gyroscope) as an alternative to other complex techniques. The aim of this study was to evaluate the effects of right ventricular (RV) pacing on CAR. A sheep heart was initially paced from the right atrium to induce a normal activation sequence at a fixed heart rate (AAI mode) and then an atrioventricular pacing was performed (DOO mode, AV delay = 60 ms).

Clinical evaluation of internal hemodiafiltration (iHDF): a diffusive-convective technique performed with internal filtration enhanced high-flux dialyzers.

Aim: Efficiency in removing middle molecules such as beta2-microglobulin (beta2-MG) is one of the main purposes of modern dialytic therapy. In order to achieve this, techniques requiring complex machines and substitution fluid have been developed over recent years. Alternatively, the internal filtration/back filtration phenomenon can be used.

[Prognosis of cognition in congenital hypothyroidism following early treatment. Double effect hypothesis].

Introduction: The prevention of mental retardation due to congenital hypothyroidism by treating it at an early stage is one of the great achievements of contemporary preventive medicine. Nevertheless, the children suffering from this disease are affected by selective cognitive deficits whose origin remains a controversial issue.

Patients And Methods: We describe the results from a cohort of 100 children who have been diagnosed as suffering from congenital hypothyroidism in La Havana since 1989 and whose cognitive performance has since been periodically evaluated.

Mathematical modeling of fluid dynamics in pulsatile cardiopulmonary bypass.

The design criteria of an extracorporeal circuit suitable for pulsatile flow are quite different and more entangled than for steady flow. The time and costs of the design process could be reduced if mutual influences between the pulsatile pump and other extracorporeal devices were considered without experimental trial-and-error activities. With this in mind, we have developed a new lumped-parameter mathematical model of the hydraulic behavior of the arterial side of an extracorporeal circuit under pulsatile flow conditions.

Hydraulic functional characterisation of aortic mechanical heart valve prostheses through lumped-parameter modelling.

Lumped-parameter modelling techniques are proposed as a method for studying the hydraulic characteristics of mechanical prosthetic heart valves (PHVs). The global hydraulic behaviour of PHVs in the open position was modelled by taking into account the (nonlinear) resistive and (linear) inertial factors governing the time-dependent relationship between transvalvular pressure drop and fluid flow rate, and neglecting the leaflets' opening and closure transient phenomena. Statistically defined indices associated to the parameters' values attest how properly the model describes PHV hydraulic behaviour.

Development of a new disposable pulsatile pump for cardiopulmonary bypass: computational fluid-dynamic design and in vitro tests.

A newly conceived blood pump for pulsatile cardiopulmonary bypass (CPB) is presented. The new device's main design features (fully disposable pumping head with ring shaped valves) were intended to overcome the factors that today limit the use of pulsatile blood pumps, i.e.

An approach to computer automation of the extracorporeal circulation.

In order to move towards extracorporeal circulation (ECC) automation, a virtual simulation of the process was designed. The ECC model is composed of a virtual patient linked to a virtual ECC circuit. A user interface panel allows to set control parameters for the simulation and to visualize results.

A computational study of the hemodynamics after "edge-to-edge" mitral valve repair.

Edge-to-edge mitral valve repair consists in suturing the free edge of the leaflets to re-establish coaptation in prolapsing valves. The leaflets are frequently sutured at the middle and a double orifice valve is created. In order to study the hemodynamic implications, a parametric model of the left heart has been developed.

In vitro steady-flow analysis of systemic-to-pulmonary shunt haemodynamics.

A modified Blalock-Taussig shunt is a connection created between the systemic and pulmonary arterial circulations to improve pulmonary perfusion in children with congenital heart diseases. Survival of these patients is critically dependent on blood flow distribution between the pulmonary and systemic circulations which in turn depends upon the flow resistance of the shunt. Previously, we investigated the pressure-flow relationship in rigid shunts with a computational approach.

Modeling of the Norwood circulation: effects of shunt size, vascular resistances, and heart rate.

Hypoplastic left heart syndrome is the most common lethal cardiac malformation of the newborn. Its treatment, apart from heart transplantation, is the Norwood operation. The initial procedure for this staged repair consists of reconstructing a circulation where a single outlet from the heart provides systemic perfusion and an interpositioning shunt contributes blood flow to the lungs.

The pumping oxygenator: design criteria and first in vitro results.

A new project is presented, the pumping oxygenator, functionally integrating pulsatile pumping and blood oxygenation in a single device. Solid, semipermeable silicone membranes allow gas exchange and simultaneously transfer energy from pressurized gas to blood thanks to their distensibility and to inlet and outlet 1-way valves. Two small-sized (1 m2 exchange surface area) prototypes were designed, constructed, hydraulically characterized, and subjected to gas transfer evaluation tests.

Scaling approach to study the changes through the gestation of human fetal cardiac and circulatory behaviors.

During human gestation, fetal body size increases considerably and important transformations occur to hemodynamics of the cardiovascular system of the fetus. Vascular compliances and resistances as well as the cardiac function show important changes. In order to investigate these modifications, a mathematical approach based on scaling techniques was developed.