Hemodynamic monitoring in childhood

Hemodynamic monitoring is indicated in children with impending or manifest cardiocirculatory failure. Since cardiocirculatory failure is characterized by an imbalance between oxygen delivery and oxygen demand due to perfusion failure, the parameters monitored should aid in the assessment of these oxygen variables. Oxygen delivery depends on oxygen content and cardiac output. Cardiac output is determined by heart rate and stroke volume; stroke volume by preload, afterload and contractility. Since the direct measurement of oxygen consumption routinely is almost impossible, global oxygen utilization represented by mixed venous oxygen saturation may be used to quantify the relationship between oxygen delivery and oxygen consumption. Justification of invasive hemodynamic monitoring depends among other things on an optimal balance between usefulness of information and complications associated with the techniques used. In future, the development of further noninvasive techniques and the scientific evaluation of recommended monitoring techniques are prospects in cardiovascular monitoring in childhood.     

Hemodynamic monitoring in sepsis

Arterial waveform analysis that does not require continuous calibration, impedance cardiography, electrical cardiometry, velocity-encoded phase contrast magnetic resonance imaging (MRI), pulsed dye densitometry, noninvasive pulse pressure analysis using tonometry, suprasternal Doppler, partial CO2 rebreathing techniques, and transcutaneous Doppler are just some of the other emerging technologies not described in this review that may be used routinely in the management of sepsis and septic shock in the very near future. These innovative approaches may further increase our ability to optimize patients' fluid status and hemodynamics. We also have ability to monitor the microcirculation. This increasingly sophisticated approach to the management of sepsis and septic shock will hopefully translate into better patient outcomes. However, optimal use of any hemodynamic monitoring requires an understanding of its physiologic underpinnings. Accurate interpretation of the hemodynamic information coupled with a protocolized management algorithm is the cornerstone of an effective resuscitation effort. Many forms of hemodynamic monitoring have emerged over the past 20 to 30 years with no convincing evidence for the superiority of any single techniques (Table 2). The goal of hemodynamic monitoring and optimization is to combat the systemic imbalance between tissue oxygen supply and demand ranging from global tissue hypoxia to overt shock and multiorgan failure. It remains unproven that hemodynamic monitoring of disease progression can effectively change patient outcome. However, despite our increased understanding of sepsis pathophysiology, mortality and morbidity from the disease remains high. Therefore, the search for the optimal parameters in resuscitation and the best way they can be monitored will continue.     

Hemodynamic monitoring.

Hemodynamic monitoring is one of the most exciting and potentially useful technologies in critical care. Hemodynamic monitoring, particularly the PAC, is the technology most often associated with the critical care unit. However, it is a difficult technology to master and is associated with clear (although infrequent) serious complications. It can also be associated with increased costs. With appropriate implementation, this technology can improve patient outcome and moderately reduce costs. Appropriate implementation is not easy with this technology. This type of technology should only be employed in hospitals willing to invest the education and quality monitoring to ensure its appropriate application. As a part of this infrastructure, physicians and nurses need frequent communication in terms of what is expected from this technology for each patient.     

Hemodynamic monitoring in respiratory care.

Continuous, invasive hemodynamic monitoring of patients in respiratory failure is an important aspect of total respiratory care. Understanding both the technical and physiological principles underlying hemodynamic monitoring is therefore important for respiratory care practitioners. This review is designed to meet this need by (1) addressing the technical aspects of hemodynamic monitoring (catheters, transducers, and monitors), (2) discussing the determinants of commonly measured hemodynamic variables (intravascular pressures and cardiac output), and (3) offering an orderly approach to hemodynamic data that allows for rapid determination of the patient's physiologic state and appropriate diagnostic possibilities. These principles are illustrated by five examples.     

Hemodynamic monitoring in postanesthesia care units

Sophisticated practice modalities, advances in technology, and the increase of sicker and older patients undergoing surgery mandate an expansion of all PACU nurses' skill and knowledge base. Invasive hemodynamic monitoring, as well as the quantitative assessment of cardiovascular function that it provides, is both feasible and necessary as an adjunct tool in today's PACU. Hemodynamic monitoring should be used only when a specific management decision is being considered and when the physician is committed to act on the data obtained. Once instituted, it is the nurse's responsibility to care for the patient safely and provide accurate and reliable data for collaborative assessment.     

Hemodynamic monitoring in the operating room

Cardiopulmonary homeostasis for the high risk surgical patient is dependent on invasive monitoring techniques which are designed to allow for the early detection of physiological dysfunction during the development stages. One must maintain both minimum and maximum predetermined cardiorespiratory values by the early utilization of specific therapeutic intervention in order to counter the physiological deviation from the previously determined acceptable values.     

从体循环监测走向微循环监测

对于危重病患者,初期治疗的目标是尽早纠正组织缺氧,以防止细胞功能障碍或细胞死亡,扼制器官功能障碍的发生.组织氧供(DO_2)与氧耗(VO_2)的平衡是脆弱的,不论是低氧血症,还是低心排血量,都可以破坏DO_2/VO_2平衡.严重的组织缺氧是致命性杀手,因此,要力求早期启动治疗性干预措施,这是经过长期的临床实践而形成危重病医学的一项基本概念.     

Hemodynamic monitoring in shock and implications for management

Objective

Shock is a severe syndrome resulting in multiple organ dysfunction and a high mortality rate. The goal of this consensus statement is to provide recommendations regarding the monitoring and management of the critically ill patient with shock.

Methods

An international consensus conference was held in April 2006 to develop recommendations for hemodynamic monitoring and implications for management of patients with shock. Evidence-based recommendations were developed, after conferring with experts and reviewing the pertinent literature, by a jury of 11 persons representing five critical care societies.

Data synthesis

A total of 17 recommendations were developed to provide guidance to intensive care physicians monitoring and caring for the patient with shock. Topics addressed were as follows: (1) What are the epidemiologic and pathophysiologic features of shock in the ICU? (2) Should we monitor preload and fluid responsiveness in shock? (3) How and when should we monitor stroke volume or cardiac output in shock? (4) What markers of the regional and micro-circulation can be monitored, and how can cellular function be assessed in shock? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock? One of the most important recommendations was that hypotension is not required to define shock, and as a result, importance is assigned to the presence of inadequate tissue perfusion on physical examination. Given the current evidence, the only bio-marker recommended for diagnosis or staging of shock is blood lactate. The jury also recommended against the routine use of (1) the pulmonary artery catheter in shock and (2) static preload measurements used alone to predict fluid responsiveness.

Conclusions

This consensus statement provides 17 different recommendations pertaining to the monitoring and caring of patients with shock. There were some important questions that could not be fully addressed using an evidence-based approach, and areas needing further research were identified.     

Hemodynamic monitoring modalities in pediatric cardiac surgical patients

Transthoracic monitoring lines yield vital information in the care of the pediatric postoperative cardiovascular surgical patient. It is the critical care nurse, in the holistic care of the patient, who integrates this data into the daily plan of care. Invasive monitoring carries risks; therefore, guidelines for care must be followed. The care of these critically ill infants requires a multifactoral approach. Hemodynamic monitoring is one of many avenues that we follow in the intensive care unit.     

Hemodynamic monitoring over the past 10 years

Changes in hemodynamic monitoring over the past 10 years have followed two paths. First, there has been a progressive decrease in invasive monitoring, most notably a reduction in the use of the pulmonary artery catheter because of a presumed lack of efficacy in its use in the management of critically ill patients, with an increased use of less invasive monitoring requiring only central venous and arterial catheterization to derive the same data. Second, numerous clinical trials have documented improved outcome and decreased costs when early goal-directed protocolized therapies are used in appropriate patient populations, such as patients with septic shock presenting to Emergency Departments and high-risk surgical patients before surgery (pre-optimization) and immediately after surgery (post-optimization). Novel monitoring will be driven more by its role in improving outcomes than in the technical abilities of the manufacturers.     

Hemodynamic monitoring over the past 10 years

Changes in hemodynamic monitoring over the past 10 years have followed two paths. First, there has been a progressive decrease in invasive monitoring, most notably a reduction in the use of the pulmonary artery catheter because of a presumed lack of efficacy in its use in the management of critically ill patients, with an increased use of less invasive monitoring requiring only central venous and arterial catheterization to derive the same data. Second, numerous clinical trials have documented improved outcome and decreased costs when early goal-directed protocolized therapies are used in appropriate patient populations, such as patients with septic shock presenting to Emergency Departments and high-risk surgical patients before surgery (pre-optimization) and immediately after surgery (post-optimization). Novel monitoring will be driven more by its role in improving outcomes than in the technical abilities of the manufacturers.     

Hemodynamic studies of nifedipine (Adalat) in pulmonary hypertension in childhood

Under long-term oral treatment with nifedipine (N) 2 of 3 patients (2 children with VSD and Eisenmenger, 1 patient with Truncus I after corrective surgery) showed a remarkable improvement in exercise tolerance and reduction in the total pulmonary resistance. Therefore a single-dose testing with N was performed in 9 patients aged 2 to 20 years with primary pulmonary hypertension (n = 2), secondary pulmonary hypertension because of congenital heart disease with intracardiac shunts (n = 6) and after correction of Truncus Type I (n = 1). Before and after the injection of 0.5 mcg/kg of N into the main pulmonary artery, pulmonary artery pressure, cardiac output and systolic blood pressure were measured at 1 minute intervals during right heart catheterization. The maximal reaction occurred 3 to 4 minutes after the injection. The total pulmonary vascular resistance decreased significantly from 2684.2 +/- 1829.2 to 1300.2 +/- 1117.0 dyn.sec.cm-5.m2 (p less than 0.025), the cardiac index increased significantly from 3.1 +/- 1.65 to 5.73 +/- 1.95 l/min.m2 (p less than 0.01) concomitantly with a mild reduction in the mean pulmonary artery pressure. No significant change in heart rate and systolic blood pressure was seen; no side effects were observed. 4 of the 5 patients with the highest pulmonary vascular resistance showed the best positive reactions. Therefore these 9 patients may benefit from a long-term oral treatment with nifedipine.     

Clinical review: Hemodynamic monitoring in the intensive care unit

Since the beginning of modern anesthesia, in 1846, the anesthetist has relied on his natural senses to monitor the patient, aided more recently by simple technical devices such as the stethoscope. There has been a tremendous increase in the availability of monitoring devices in the past 30 years. Modern technology has provided a large number of sophisticated monitors and therapeutic instruments, particularly in the past decade. Most of these techniques have enhanced our understanding of the mechanism of the patients' decompensation and have helped to guide appropriate therapeutic interventions. As surgery and critical care medicine have developed rapidly, patient monitoring capability has become increasingly complex. The most important aspect in monitoring the critically ill patient is the detection of life-threatening derangements of vital functions. Aggressive marketing strategies have been promoted to monitor almost every aspect of the patient's status. However, these strategies are only telling us what is possible; they do not tell us whether they enhance patient safety, improve our therapy, or even improve patient outcome.     

Hemodynamic monitoring in the care of the critically ill neuroscience patient

Hemodynamic monitoring in the care of the critically ill neuroscience patient provides information that assists the clinician in minimizing secondary neuronal injury. Whereas no technology replaces the critical care nurse's physical assessment, hemodynamic and neurological monitoring provides additional data beyond what is possible with the clinical examination alone. If neurological technology, such as intracranial pressure monitoring, is not available, hemodynamic monitoring along with the neurological examination provides limited but useful information essential to minimizing secondary neuronal injury. The use of hemodynamic monitoring in critically ill neuroscience patients is best exemplified in the management of cerebral vasospasm after aneurysmal subarachnoid hemorrhage. Although improved outcomes have not been scientifically substantiated, multimodality monitoring of intracranial dynamics and systemic hemodynamics and manipulation of these parameters during hypertensive hypervolemic hemodilution therapy may lessen the incidence of cerebral infarction secondary to vasospasm. Monitoring systemic hemodynamics and intracranial dynamics simultaneously assists in prevention, prompt recognition, and effective treatment of neurological deterioration.