Goal-oriented hemodynamic therapy.
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Cardiac Output↗
Biomedical subjects
W C Shoemaker
Publications and source records attributed to W C Shoemaker.
Noninvasive physiologic monitoring of high-risk surgical patients.
OBJECTIVES: To study the feasibility of multicomponent noninvasive monitoring, consisting of a new bioimpedance method for estimating cardiac output together with routine pulse oximetry and transcutaneous oximetry, and to compare physiologic data obtained noninvasively with hemodynamic and oxygen transport data obtained by standard invasive pulmonary artery thermodilution catheter to evaluate circulatory function in high-risk surgical patients. DESIGN: Prospective descriptive analysis of the time course of physiologic patterns in surgical patients. SETTING: University-run county hospital. PATIENTS: Seventy-one consecutively monitored, high-risk critically ill surgical patients in their perioperative period. OUTCOME MEASURES: Simultaneous measurements by invasive and noninvasive methods to describe and compare the temporal physiologic patterns of survivors and nonsurvivors. RESULTS: The new impedance cardiac output estimations closely approximated those of the thermodilution method (r = 0.82, P < .001). Episodes of hypotension, tachycardia, low cardiac index, arterial hemoglobin desaturation, low transcutaneous oximetry, reduced oxygen delivery, and low oxygen consumption occurred with both groups but were more pronounced in the nonsurvivors than in the survivors. Noninvasive monitoring provided information similar to that of the thermodilution method. Both approaches indicated low flow and poor tissue perfusion (oxygenation) that was worse in the nonsurvivors. CONCLUSIONS: The multicomponent noninvasive monitoring provides continuous online, real-time displays of physiologic data that allow immediate recognition of circulatory dysfunction as well as the means to titrate therapy to appropriate predetermined therapeutic goals. The noninvasive systems are easy to apply, safe, inexpensive, reasonably accurate, and cost-effective.
Adult↗
Invasive and noninvasive monitoring for early recognition and treatment of shock in high-risk trauma and surgical patients.
The proposed noninvasive monitoring systems provide the essential hemodynamic and oxygen transport information previously available only by invasive thermodilution catheters. More importantly, the noninvasive systems provide continuous on-line real-time displays of data which allow immediate recognition of circulatory abnormalities and provide a means to titrate therapy to appropriate therapeutic goals. The noninvasive systems are easy to apply, safe, inexpensive, and more cost-effective than invasive monitoring.
Emergencies↗
Oxygen transport and oxygen metabolism in shock and critical illness. Invasive and noninvasive monitoring of circulatory dysfunction and shock.
The common underlying physiologic problem in shock is low flow from hypovolemia or maldistributed microcirculatory flow from uneven vasoconstriction, leading to inadequate tissue perfusion (hypoxia), often in the face of increased metabolic demands. Noninvasive monitoring which was found to provide similar information to that of invasive monitoring, was used in the earliest period of time shortly after admission to the emergency department to provide objective physiologic criteria as therapeutic goals for each of the three major circulatory components: cardiac, pulmonary, and tissue perfusion functions. A clinical algorithm or branch-chain decision tree for high-risk surgical patients was developed from decision rules based on survivor and nonsurvivor patterns, outcome predictors, prospective controlled clinical trials of the oxygen delivery/oxygen consumption (DO2/VO2) concept, and the DO2/VO2 responses of a wide variety of therapeutic agents.
Decision Trees↗
Noninvasive hemodynamic monitoring of critical patients in the emergency department.
OBJECTIVE: To evaluate the feasibility of multicomponent noninvasive hemodynamic monitoring in critical emergency patients and to compare this technique with simultaneous invasive monitoring by the pulmonary artery thermodilution catheter. METHODS: A prospective observational study was done comparing invasive monitoring and noninvasive monitoring in 60 critically ill or injured patients who required hemodynamic monitoring shortly after entering the ED of a university-affiliated country hospital. Cardiac output (CO) values measured by the standard thermo-dilution pulmonary artery catheter technique were compared with simultaneously obtained measurements using a noninvasive bioimpedance method. Concurrent measurements were made of pulse oximetry to screen pulmonary function and transcutaneous oximetry to assess tissue perfusion. RESULTS: The impedance CO values closely approximated those for the thermodilution method; r 0.81, p < 0.001. Significant circulatory abnormalities, including hypotension, reduced cardiac index, arterial hemoglobin desaturation, tissue hypoxia, reduced O2 delivery, and consumption, were found in 54 of the 60 (90%) patients. The cardiac index decreased in 44% of the patients, the transcutaneous O2 decreased in 39%, and the O2 saturation by pulse oximetry fell in 22% during the observation period in the ED (commonly lasting 2-8 hours). CONCLUSIONS: Noninvasive monitoring can provide hemodynamic and perfusion information previously available only by invasive thermodilution catheters. Such noninvasive monitoring can display continuous on-line real-time data, allowing immediate recognition of circulatory abnormalities and providing a means to titrate therapy to appropriate therapeutic goals.
Adult↗
Noninvasive cardiac index monitoring in gunshot wound victims.
OBJECTIVE: To evaluate a bioimpedance device for the noninvasive measurement of cardiac index (CI) against standard thermodilution measurements in patients with gunshot wounds. METHODS: A prospective open-label performance evaluation was done using a convenience sample of gunshot wound victims initially treated in the resuscitation area of a high-volume, urban ED. After initial resuscitation, patients had a flow-directed pulmonary artery catheter placed for thermodilution cardiac output (CO) measurements. The CO measurements were made in triplicate and averaged. Estimates of body surface area were used to convert these measurements to CI estimates. Electrodes for bioimpedance measurements were placed as soon as practical after ED arrival. Simultaneous measurements of CI using the bioimpedance device were made as clinically indicated during each patient's hospital course. RESULTS: There were 54 patients studied, with an overall mean (+/- SEM) age of 32 +/- 3 years, Revised Trauma Score of 6.7 +/- 0.4, and Injury Severity Scale score of 22 +/- 3. There were 42 survivors and 12 nonsurvivors. The CI as estimated by bioimpedance correlated well with that measured by thermodilution (r = 0.79, p < or = 0.02). The precision of the invasive and noninvasive measurements was 1.1 L/min/m2; the bias was -0.011 L/min/m2. In 24 patients with thoracic injuries requiring tube thoracostomy or thoracic surgery, the correlation of the 2 devices was r = 0.71 with precision and bias of 1.4 L/min/m2 and -0.018 L/min/m2, respectively. CONCLUSIONS: Cardiac index can be noninvasively estimated in acutely injured patients with gunshot wounds using a bioimpedance device. Further study of bioimpedance measurements as a guide to volume therapy is warranted.
Adult↗
Resuscitation from severe hemorrhage.
The potential to be successfully resuscitation from severe traumatic hemorrhagic shock is not only limited by the "golden 1 hr", but also by the "brass (or platinum) 10 mins" for combat casualties and civilian trauma victims with traumatic exsanguination. One research challenge is to determine how best to prevent cardiac arrest during severe hemorrhage, before control of bleeding is possible. Another research challenge is to determine the critical limits of, and optimal treatments for, protracted hemorrhagic hypotension, in order to prevent "delayed" multiple organ failure after hemostasis and all-out resuscitation. Animal research is shifting from the use of unrealistic, pressure-controlled, hemorrhagic shock models and partially realistic, volume-controlled hemorrhagic shock models to more realistic, uncontrolled hemorrhagic shock outcome models. Animal outcome models of combined trauma and shock are needed; a challenge is to find a humane and clinically realistic long-term method for analgesia that does not interfere with cardiovascular responses. Clinical potentials in need of research are shifting from normotensive to hypotensive (limited) fluid resuscitation with plasma substitutes. Topics include optimal temperature, fluid composition, analgesia, and pharmacotherapy. Hypotensive fluid resuscitation in uncontrolled hemorrhagic shock with the addition of moderate resuscitative (28 degrees to 32 degrees C) hypothermia looks promising in the laboratory. Regarding the composition of the resuscitation fluid, despite encouraging results with new preparations of stroma-free hemoglobin and hypertonic salt solutions with colloid, searches for the optimal combination of oxygen-carrying blood substitute, colloid, and electrolyte solution for limited fluid resuscitation with the smallest volume should continue. For titrating treatment of shock, blood lactate concentrations are of questionable value although metabolic acidemia seems helpful for prognostication. Development of devices for early noninvasive monitoring of multiple parameters in the field is indicated. Molecular research applies more to protracted hypovolemic shock followed by the systemic inflammatory response syndrome or septic shock, which were not the major topics of this discussion.
Animals↗
Temporal physiologic patterns of shock and circulatory dysfunction based on early descriptions by invasive and noninvasive monitoring.
In the past, most investigators failed to consider time relationships in their studies of circulatory problems. Because of this, data obtained in middle- or late-stage shock during organ failure are often presented as being characteristic of specific shock syndromes. Even "early" studies are not physiologically early, but instead have often come to mean early after ICU admission or early after life-threatening hypotensive events. The hypotensive episode represents decompensation of protective circulatory mechanisms, not the beginning of circulatory dysfunction. Early monitoring demonstrates that circulatory changes do not start with hypotension, but with the precipitating event, i.e., hemorrhage, trauma, surgery, or sepsis. When monitoring is started after hypotension, the first half of the problem is missed. It is, therefore, appropriate to focus on the earliest period of circulatory dysfunction with noninvasive methods to evaluate pathophysiology, to predict outcome, and to propose therapeutic protocols to improve outcome. Invasive monitoring is generally accepted as the "gold standard" for critically ill patients. The pulmonary artery flotation catheter has translated information to the bedside previously only available in cardiac catheterization laboratories, forever changing the way we treat ICU patients. Newer high-tech hardware and software innovations in the impedance method give more accurate and reliable cardiac index (CI) measurements that now satisfactorily agree with thermodilution in most clinical conditions. Minor disparities are more than made up for by the continuous online display of data. This impedance device, combined with pulse oximetry and transcutaneous oximetry, provides a feasible, noninvasive hemodynamic monitoring system that can be applied in a manner similar to electrocardiogram electrodes in the emergency department, operating room, ICU, hospital floors, and doctor's offices. More importantly, noninvasive monitoring provides a continuous, online, real-time display of hemodynamic data needed to titrate therapy rapidly and expeditiously. This is a major advantage, since therapy is more effective if given prophylactically or early and then titrated to optimal goals. Noninvasive monitoring provides a powerful method for objective evaluation of early, rapidly changing circulatory dynamics beginning with the precipitating event. This gives a new and different view of circulatory failure, exceeding the boundaries of our old concepts of shock based on blood pressure, subjective symptoms, and imprecise signs. Data of survivors revealed increased cardiac function (CI and oxygen delivery) shortly after surgery, trauma, and sepsis; this response is needed to meet the increased metabolic demands defined by the increased oxygen consumption. Nonsurvivors have limited responses to the added metabolic demands of external stressors. Therapy should augment naturally occurring compensations, but it must be given promptly within appropriate time limits.
Hemodynamics↗
Early physiologic patterns in acute illness and accidents: toward a concept of circulatory dysfunction and shock based on invasive and noninvasive hemodynamic monitoring.
The aim of the present study was to explore methods, concepts, and techniques that provide recognition of circulatory deficiencies at the earliest possible time in the patient's illness. We used both the standard invasive pulmonary artery thermodilution catheter and noninvasive hemodynamic monitoring systems consisting of a new bioimpedance cardiac output device, pulse oximetry, transcutaneous oxygen (PtCO2) and carbon dioxide tensions as well as the transcutaneous oxygen tension/fraction of inspired oxygen ratio (PtCO2/FIO2). These three noninvasive systems were used to evaluate cardiac function, pulmonary function, and tissue perfusion, respectively. This approach to early noninvasive monitoring is based on recent evidence suggesting that poor tissue perfusion and oxygenation initiate circulatory dysfunction that leads to shock and organ failure. We studied 303 acute episodes of circulatory dysfunction and shock in 261 patients in a university-run county hospital; 75 were acute traumatic injuries and 109 acute nontrauma medical emergencies on admission to the emergency department, and 77 ICU patients with an acute illness or exacerbation of their current illness. The study was a prospective, descriptive study to identify early abnormal circulatory patterns reflecting the cardiac, pulmonary, and perfusion functions associated with death and with survival. We described noninvasively monitored patterns in individual illustrative cases, in common etiologic groups, and in physiologic categories representing various abnormal functional patterns. We found that hypotensive shock usually was preceded by episodes of high flow followed by low flow and inadequate tissue perfusion indicated by reduced PtCO2; this frequent pattern was modified by associated co-morbid conditions, especially hypovolemia, limited cardiac reserve capacity, age, hypertensive states, and increased body metabolism from infection, trauma, stress, exercise, temperature, and endocrine disorders. Reduced pulmonary function occurred in 18% of emergency patients; these were usually patients with thoracic trauma, severe hypovolemia, head injuries, chronic obstructive pulmonary disease, asthma, drug overdose, and central nervous system failure (massive stroke and coma). We concluded that noninvasive measurements identify early circulatory problems reliably and provide objective criteria for physiologic analysis as well as for definition of therapeutic goals and titration of therapy.
Adult↗
Intraoperative maintenance of tissue perfusion prevents ARDS. Adult Respiratory Distress Syndrome.
Patients undergoing prolonged, complex oncological surgery are at increased risk of developing the adult respiratory distress syndrome (ARDS) and other organ failures. Our hypothesis is that maintaining adequate tissue perfusion and oxygenation may prevent tissue hypoxia and acidosis in pulmonary, peripheral, and splanchnic microcirculations. Experimental evidence suggests that the hypoxic, acidotic endothelium stimulates the release of cytokines, kinins, and other mediators. We developed and tested an intraoperative protocol for surgical patients likely to develop ARDS and organ dysfunction; the protocol focuses on the intraoperative period but is not limited to this time. Nitroglycerin and fluids were used to maintain tissue perfusion and prevent tissue hypoxia as reflected by transcutaneous oxygen tension values. In 155 high-risk patients, none developed ARDS. We conclude that maintenance of tissue perfusion and oxygenation in high-risk surgical patients decreases the incidence of ARDS.
Adult↗
Use of large databases for resolving critical care problems.
Large databases allow for rapid access to large volumes of data. To convert raw data to information, large numbers of data points must be correlated into a descriptive pattern that can be interpreted by the user. Databases must be constructed so as to allow reliable extraction of the raw data into a format that supports analysis of events in a meaningful, objective, and reproducible manner. Databases must be responsive to a variety of users. They must not demand unrealistic amounts of effort on those responsible for data entry. Standard protocols in various stages of development will make databases easier to use and more reliable. Database management tools such as the Internet and the National Library of Medicine will become more integrated into the practice of critical care medicine at all levels, including administration, clinical care, and research. This article provides an overview of the capabilities and difficulties associated with large databases. The major areas of use of large databases in the hospital setting are administration, bibliographic, patient care, research, and education. Each of these areas has different requirements and is supported by different types of databases. The advantages and disadvantages of linear, relational, and object-oriented databases are discussed. Issues relating to methods of data entry and the accuracy and reliability of data are discussed. The challenges involving integration of various sources of data and the interfacing of devices are reviewed.
Critical Care↗
Application of an artificial intelligence program to therapy of high-risk surgical patients.
We developed an artificial intelligence program from a large computerized database of hemodynamic and oxygen transport measurements together with prior studies defining survivors' values, outcome predictors, and a branched-chain decision tree. The artificial intelligence program was then tested on the data of 100 survivors and 100 nonsurvivors not used for the development of the program or other analyses. Using the predictor as a surrogate outcome measure, the therapy recommended by the program improved the predicted outcome 3.16% per therapeutic intervention while the actual therapy given increased outcome 1.86% in surviving patients; the artificial intelligence-recommended therapy improved outcome 7.9% in nonsurvivors, while the actual therapy given increased predicted outcome -0.29% in nonsurvivors (p < .05). There were fewer patients whose predicted outcome decreased after recommended treatment (14%) than after the actual therapy given (37%). Review of therapy recommended by the program did not reveal instances of inappropriate or potentially harmful recommendations.
Artificial Intelligence↗
Prospective, randomized trial of survivor values of cardiac index, oxygen delivery, and oxygen consumption as resuscitation endpoints in severe trauma.
The objective was to test prospectively supranormal values of cardiac index (CI), oxygen delivery index (DO2I), and oxygen consumption index (VO2I) as resuscitation goals to improve outcome in severely traumatized patients. We included patients > or = 16 years of age who had either (1) an estimated blood loss > or = 2000 mL or (2) a pelvic fracture and/or two or more major long bone fractures with > or = four units of packed red cells given within six hours of admission. The protocol resuscitation goals were CI > or = 4.5 L/min/m2, DO2I > or = 670 mL/min/m2, and VO2I > or = 166 mL/min/m2 within 24 hours of admission. The control resuscitation goals were normal vital signs, urine output, and central venous pressure. The 50 protocol patients had a significantly lower mortality (9 of 50, 18% vs. 24 of 65, 37%) and fewer organ failures per patient (0.74 +/- 0.28 vs. 1.62 +/- 0.45) than did the 75 control patients. We conclude that increased CI, DO2I, and VO2I seen in survivors of severe trauma are primary compensations that have survival value; augmentation of these compensations compared to conventional therapy decreases mortality.
Adolescent↗
Elevation of systemic oxygen delivery in the treatment of critically ill patients.
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Critical Illness↗
Monitoring and therapy for young trauma patients.
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Hemodynamics↗
Cytokine, complement, and endotoxin profiles associated with the development of the adult respiratory distress syndrome after severe injury.
OBJECTIVE: The adult respiratory distress syndrome (ARDS) is a frequent complication after severe accidental trauma. This study examines the hypothesis that increased systemic concentrations of proinflammatory cytokines, endotoxin, or complement fragments may predict the development of ARDS. DESIGN: Prospective, observational study. SETTING: Two Level I university trauma centers. PATIENTS: Fifteen severely injured patients (Injury Severity Score of > or = 25). INTERVENTIONS: Standard emergency department, operating room, and intensive care unit management. MEASUREMENTS AND MAIN RESULTS: Plasma samples were obtained at 4-hr intervals from the time of injury and were assayed for concentrations of endotoxin, tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-6, IL-8, and complement fragments C3a and C4a. Hemodynamic and oxygen metabolism variables also were measured at 4-hr intervals after injury. Seven patients developed ARDS and eight patients did not. The PaO2/FIO2 ratio was significantly decreased in the patients with ARDS compared with non-ARDS patients as early as 4 hrs postinjury, and remained significantly decreased throughout the initial 24 hrs after severe accidental injury. Plasma IL-8, IL-6, C3a, and C4a concentrations were markedly increased starting in the immediate postinjury period in both ARDS and non-ARDS patients, but no significant differences were found between the two groups until 16 hrs after injury when plasma IL-8, C3a, and C4a concentrations became significantly higher in the ARDS group. Neither the ARDS nor non-ARDS patients showed the presence of circulating IL-1 beta, TNF-alpha, or endotoxin at any postinjury time point. CONCLUSIONS: These results demonstrate that measurements of plasma concentrations of proinflammatory cytokines, endotoxin, or complement fragments are not helpful in predicting the development of ARDS after severe accidental injury.
Adult↗
Critical care research in the 1990s: how our perceptions affect creativity.
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Creativity↗
Temporal patterns of radiographic infiltration in severely traumatized patients with and without adult respiratory distress syndrome.
We prospectively evaluated the patterns of pulmonary structural and functional changes in 100 consecutive surgical intensive care unit trauma patients who had (1) emergent major surgery, (2) a pelvic fracture, or (3) two or more major long bone fractures. For each patient, arterial blood gas measurements (ABGs), central venous pressure (CVP), pulmonary capillary occlusion pressure (PAOP), thoracic compliance, arterial oxygen tension/fraction of inspired oxygen (PAO2/FIO2), pulmonary venous admixture (Qs/Qt), and portable chest roentgenograms were sequentially tracked. The senior staff radiologist interpreted all chest roentgenograms. Pulmonary infiltration was quantitated in each of six fields using a scale ranging from 0 to 4, with 0 being no infiltration and 4 being the maximum. Adult respiratory distress syndrome (ARDS) was defined as follows: Qs/Qt > or = 20%, PAO2/FIO2 < 250 or both; dependence on mechanical ventilation for life support for > or = 24 hours; PAOP or CVP or both < 20 mm Hg; and thoracic compliance < 50 mL/cm H2O. Time zero (T0) the time of onset of ARDS, was defined as the time these criteria were met. Eighty-three of 100 study group patients had penetrating injuries, and 17 were admitted with blunt trauma. Fifty-one of 100 patients developed ARDS: 36 of 51 died. Only 4 of 49 (8%) patients without ARDS died. The injured lungs of patients with and without ARDS had similar amounts of infiltration over most measured time intervals. The noninjured lungs of the ARDS patients, however, had significantly greater infiltration than those without ARDS at T0 and over subsequent time intervals.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗