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Biomedical subjects

W C Shoemaker

Publications and source records attributed to W C Shoemaker.

At least 55 records · Page 3Linked to original sources
PubMed1994

Temporal patterns of hemodynamics, oxygen transport, cytokine activity, and complement activity in the development of adult respiratory distress syndrome after severe injury.

The aim of this study was to search for early inflammatory mediators in severely traumatized patients that could predict the occurrence of adult respiratory distress syndrome (ARDS). We measured sequential plasma levels of tumor necrosis factor (TNF), interleukin 1 (IL-1), interleukin 6 (IL-6), interleukin 8 (IL-8), complement fragment C3a, and endotoxin. In addition, we measured sequentially the values of hemodynamics, oxygen transport, and pulmonary function. The temporal patterns seen in the patients who developed ARDS were compared with those who did not. In the patients who developed ARDS, the first observed findings were low cardiac index (CI) and oxygen delivery (DO2) followed by progressive increases in IL-6, IL-8 and C3a levels, worsening of pulmonary function, and increases in hemodynamic values. The maximum values of IL-6, IL-8, and C3a occurred after the onset of ARDS. In the patients who did not develop ARDS, initial oxygen transport values were not low, the levels of IL-6, IL-8, and C3a decreased rapidly from their initial peaks, and there were no further increases in hemodynamic values. In both ARDS and nonARDS patients, no measurable quantities of TNF, IL-1, or endotoxin were found. We concluded that none of the mediators we measured reached their peaks before the onset of ARDS and none were found to be predictive of posttraumatic ARDS. However, these and other mediators may augment or intensify the development of ARDS.

Adult↗
PubMed1994

Pathophysiology, monitoring, and therapy of acute circulatory problems.

Acute circulatory problems, including shock, traditionally have been recognized and treated by subjective symptoms and vital signs (BP and HR) which represent only superficial aspects of the underlying physiology. Shock, however, is objectively diagnosed, evaluated, and treated using invasive physiologic monitoring to measure cardiac function and output, pulmonary function, and tissue perfusion. Multicomponent noninvasive monitoring systems are now being developed to obtain comparable information and provide continuous display of data on-line, in real time. These monitoring systems may be used to evaluate the effectiveness of alternative therapies, and to titrate therapy to achieve optimal physiologic goals that improve outcome.

Acute Disease↗
PubMed1994

Multicenter trial of a new thoracic electrical bioimpedance device for cardiac output estimation.

OBJECTIVE: To evaluate the capacity of a new thoracic electric bioimpedance system to estimate cardiac output compared with the conventional thermodilution method. DESIGN: Prospective, multicenter study. SETTING: A university-run county hospital, a university-run U.S. Veterans Affairs hospital, and a university-affiliated U.S. military hospital. PATIENTS: A series of 68 critically ill patients whose conditions required pulmonary artery catheter insertion. MEASUREMENTS AND MAIN RESULTS: A total of 842 simultaneous pairs of cardiac output estimations by conventional thermodilution and a new thoracic electric bioimpedance system that uses an improved signal processing technique based on an all-integer-coefficient filtering technology, using a time-frequency distribution that provides a high signal/noise ratio were evaluated. The r value was .86, r2 = .74, and p < .001 by regression analysis; the mean difference between the two methods relative to their average value was 16.6 +/- 12.9 (SD) %; the precision was 1.4 L/min or 0.8 L/min/m2; the bias was -0.013 L/min. The mean difference between successive pairs of thermodilution measurements was 8.6 +/- 0.6 (SD) %, which was about half the difference between simultaneous pairs of measurement by the two methods. The changes in impedance estimations were close to simultaneously measured changes in thermodilution estimates of cardiac output. CONCLUSIONS: The new bioimpedance system satisfactorily estimated cardiac output as measured by the thermodilution technique. The difference between the two estimations is more than made up for by the continuous noninvasive capability of the impedance system.

Adult↗
PubMed1993

Urban violence in Los Angeles in the aftermath of the riots. A perspective from health care professionals, with implications for social reconstruction.

Beginning April 29, 1992, Los Angeles, Calif, was engulfed in a 3-day insurrection reflecting the residents' responses to a legal ruling. Unlike the media-painted picture, this article argues that the enormous outburst of violence and consequential property destruction was not the exclusive domain of the citizens of South-Central Los Angeles and that available data will not support the maintenance of the prevailing uneven distribution of civic and state resources in health care, educational programs, and economic opportunities. What it does support is the proposal for a more equitable allocation of resources among institutions, groups, and peoples, complemented by community empowerment, a more civic-oriented police operation, and a more rational approach to social reconstruction in which all elements of the society are full participants. Finally, the article suggests that augmentation of the present "law and order" approach and the paramilitary police already have proven economically ineffective. Given the dominant role of the medical profession in social and civic life, it is now appropriate for the medical profession to enter the debate on policies of health improvement, violence deterrence, and the general field of social reconstruction.

Health Occupations↗
PubMed1993

Relationship between supranormal circulatory values, time delays, and outcome in severely traumatized patients.

OBJECTIVE: To describe the temporal patterns of hemodynamics and oxygen transport in survivors and nonsurvivors of severe trauma in relation to time delays, mortality, and morbidity. DESIGN: Prospective, empiric analysis. SETTING: University-run, inner city county hospital with a Level I trauma center. PATIENTS: A series of 90 consecutively monitored, severely ill trauma patients. METHODS: We followed 90 patients from admission through their hospital course, and divided the study group into patients with estimated blood loss of < or = 3000 mL and those patients with an estimated blood loss of < 3000 mL. For each patient, vital signs were recorded in the Emergency Department, operating room, recovery room, and surgical ICU. Hemodynamic and oxygen transport variables were measured at least every 12 hrs for 96 hrs postadmission. Final outcome and complications were recorded. RESULTS: In the first 24 hrs, the values of 60 survivors were significantly higher than the values of 30 nonsurvivors for mean cardiac index (4.52 +/- 1.45 vs. 3.80 +/- 1.20 L/min/m2; p < .05), oxygen delivery (670 +/- 230 vs. 540 +/- 200 mL/min/m2; p < .01), and oxygen consumption (166 +/- 48 vs. 134 +/- 47 mL/min/m2; p < .01). Thirteen (50%) of 26 patients who never attained mean survivors' values (defined as the mean survivors' values listed above) died. Also, 12 (57%) of 21 patients who took > 24 hrs to attain these values died. In contrast, only five (12%) of 43 patients who reached mean survivors' values in < or = 24 hrs died. Thirty-five of 90 patients lost < 3000 mL of blood; 17 of these 35 patients failed to reach survivors' values within 24 hrs, and 12 (71%) patients died. However, of 18 patients with an estimated blood loss of > 3000 mL, who reached survivors' values in < or = 24 hrs, only two (12%) died. The patients reaching survivors' values in < or = 24 hrs, > 24 hrs, or not at all had similar Injury Severity Scores (28 +/- 13, 26 +/- 13, and 26 +/- 12, respectively) and Trauma Scores (12 +/- 3, 13 +/- 3, and 12 +/- 3, respectively). Only six (12%) of 43 patients reaching survivors' values in < or = 24 hrs developed adult respiratory distress syndrome (ARDS), while 27 (57%) of 47 patients showed these values in > 24 hrs or never developed ARDS. CONCLUSIONS: Reaching supranormal circulatory values, especially within 24 hrs of injury, may improve survival and reduce the frequency of shock-related organ failure in severely traumatized patients.

Hemodynamics↗
PubMed1993

Unreliability of blood pressure and heart rate to evaluate cardiac output in emergency resuscitation and critical illness.

OBJECTIVE: To evaluate the reliability of the vital signs to evaluate circulatory stability as reflected by cardiac index. DESIGN: Descriptive analysis based on data gathered prospectively, using a predetermined protocol. SETTING: University-run county hospital, with a large trauma service. PATIENTS: Sixty-one high-risk trauma patients with accidental injury who were studied immediately after admission to the Emergency Department, and subsequently, 163 critically ill postoperative ICU patients. INTERVENTIONS: Standard fluid therapy, usually crystalloids, but occasionally packed red cell transfusions and colloids, as indicated by clinical criteria. MEASUREMENTS AND RESULTS: Arterial BP was measured by pressure transducer and arterial catheter; heart rate (HR) was measured by electrocardiograph signal, and cardiac output was measured by thermodilution. In sudden severe hypovolemic hypotension, the mean arterial pressure (MAP) nadir (lowest) roughly correlated (r2 = .25) with flow, but there was poor correlation (r2 = .0001) when all pressure and flow values were evaluated. The pressure and flow values were obtained throughout the course of the hypotensive episodes during the initial resuscitation in ICU patients and during terminal illnesses. CONCLUSIONS: Observations at the time of acute severe hypotensive crises that show rough correlation of MAP and cardiac index should not be extrapolated throughout the entire hypotensive period or to other less extreme clinical situations. The stress response to hypovolemia, with endogenous catecholamines and neural mechanisms, tends to maintain arterial pressure in the face of decreasing flow for a variable period of time. However, when these mechanisms are overwhelmed by prolonged hypovolemia, the pressure decreases precipitously, but not synchronously, with flow. We conclude that blood flow cannot reliably be inferred from arterial pressure and heart rate measurements until extreme hypotension occurs.

Blood Pressure↗
PubMed1993

Goals for the resuscitation of shock.

OBJECTIVE: To remind practitioners of the conventional goals of resuscitation of overt hypotensive or uncompensated shock ("ABC," for airway, breathing, and circulation) and to introduce additional goals, represented by successive letters of the alphabet, to aid clinicians in recognizing the persistence of compensated shock in the splanchnic organs and in achieving more complete resuscitation by eliminating inadequate tissue perfusion in these organs. DATA SOURCES: Review and analysis of current medical literature on shock and organ failure, combined with the author's prior research and expertise in the areas of tissue oxygenation and tonometric monitoring in the critically ill. CONCLUSIONS: In traumatic and septic shock, multiple system organ failure is associated with a persistent state of compensated shock in which hypotension and oliguria are corrected, but in which inadequate perfusion persists in the splanchnic organs and especially in the mucosal lining of the gut. The additional goals recommended include "D" for increasing the delivery of oxygen to levels that meet the metabolic demand by all tissues in the body, especially those tissues within the splanchnic circulation, and "E" for ensuring extraction and utilization of oxygen by the tissues. Future needs for goals that address reperfusion injury, translocation of bacterial toxins, and the release of toxic mediators are also considered.

Animals↗
PubMed1993

Effects of accidental trauma on cytokine and endotoxin production.

OBJECTIVE: To determine the effects of accidental injury of varying severity on interleukin (IL)-1 alpha, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha), and endotoxin release. DESIGN: Prospective, multi-unit, longitudinal study. SETTING: Emergency Departments and intensive care units of two university hospitals. PATIENTS: Trauma patients after mild, moderate, and severe injury (Injury Severity Score of < or = 10, 11 to 24, and > or = 25, respectively). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Plasma cytokine and endotoxin concentrations were measured over a 5-day period, starting within 2 hrs of accidental injury. An enzyme-linked immunosorbent assay was used to determine plasma concentrations of IL-1 alpha, IL-6, IL-8, and TNF-alpha. Plasma endotoxin concentrations were measured using a chromogenic limulus amebocyte assay. Preresuscitation samples obtained immediately on arrival in the Emergency Department, and within 2 hrs of injury, demonstrated significant increases of IL-6 and IL-8 concentrations in the severe injury group, in contrast to minimal increases seen after mild or moderate injury. Analysis of serial postresuscitation samples demonstrated rapid increases in IL-6 and IL-8 concentrations within 12 hrs of injury. IL-6 and IL-8 remained increased for 24 hrs after injury, then decreased markedly from their peak values during the next 24 hrs. Increased circulating concentrations of these cytokines continued to be present for > 5 days in the severely injured patients. IL-6 and IL-8 concentrations were only minimally increased in patients 8 and 24 hrs after moderate injury. Endotoxin and IL-1 alpha were not found in any samples, including those samples obtained serially from severely injured patients. No patient at any time point had TNF-alpha concentrations of > 35 pg/mL. CONCLUSIONS: These results demonstrate that severe injury produces rapid, large increases in circulating concentrations of IL-6 and IL-8 that may contribute to the frequent development of the adult respiratory distress syndrome and multiple organ system failure in this clinical setting.

Adult↗
PubMed1993

Hemodynamic and oxygen transport responses in survivors and nonsurvivors of high-risk surgery.

OBJECTIVES: To describe temporal hemodynamic and oxygen transport patterns in a large series of high-risk surgical patients in order to document physiologic patterns, to develop therapeutic goals for a wide range of surgical conditions, and to propose a mechanistic model for acute postoperative circulatory failure. DESIGN: Prospective, longitudinal study. Patients identified as high risk were studied prospectively. The data were analyzed immediately after they were acquired, again on formal rounds twice daily, and at a formal data review after completion of monitoring. SETTING: A university-run county hospital. PATIENTS: The patient series consisted of 708 consecutively monitored high-risk surgical patients. INTERVENTIONS: Hemodynamic and oxygen transport values and their responses to surgical trauma are known to vary widely with age and prior medical conditions; they may be used to predict outcome with a high degree of accuracy. Temporal hemodynamic and oxygen transport patterns in a large series of high-risk surgical operations were treated by one group, using a well-developed protocol. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and oxygen transport monitored variables were analyzed before, during, and at frequent intervals after surgical operations. We stratified the temporal patterns of survivors and nonsurvivors in each of the following groups: a) patients without evidence of cardiovascular disease whose preoperative baseline cardiac index values were normal; and b) patients with high or low preoperative baseline cardiac index values due to the presence of preoperatively identified medical conditions that affect the circulatory status. In addition, we stratified patients in various age ranges who were without known cardiovascular diseases. The present study analyzed over 20,000 data sets with up to 32 variables in each data set or > 500,000 values. The major findings were intraoperatively reduced circulatory functions, principally cardiac index values, oxygen delivery (DO2), and oxygen consumption (VO2). These reductions in circulatory functions intraoperatively were followed, in the early postoperative period, by increases in these variables. The postoperative increases in cardiac index, DO2, and VO2 values were greater in survivors than in nonsurvivors; these findings were more apparent when the postoperative patterns of each strata were related to their own preoperative control values. CONCLUSIONS: The data indicate that there are increased metabolic requirements after surgical trauma and that the changes in cardiac index and DO2 represent compensatory increases in circulatory functions stimulated by increased metabolic needs. However, these metabolic needs change with age, gender, severity of illness, type of operation, associated medical conditions, duration of shock, complications, organ failure, and outcome.

Aged↗
PubMed1993

Sequence of physiologic patterns in surgical septic shock.

OBJECTIVES: Gradual, almost imperceptible transitions occur between localized infection, generalized infection, systemic manifestations of the sepsis syndrome, septic shock, and death. The aim of this study was to describe the sequential pattern of hemodynamic and oxygen transport patterns of survivors and nonsurvivors of septic shock, so as to differentiate primary from secondary and tertiary events, to evaluate possible physiologic mechanisms, and to provide a template to relate the appearance of biochemical mediators to the sequence of physiologic events. DESIGN: Prospective, cohort study. SETTING: University-run county hospital. PATIENTS: A series of 300 consecutive surgical patients with septic shock; 85 survived and 215 died. INTERVENTIONS: We used specific criteria to define stages as: a) early period, the first recorded increase in cardiac output; b) middle period, time of maximal metabolic activity defined as the highest recorded oxygen consumption (VO2); and c) late period, the time of death or recovery. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and oxygen transport variables were measured at frequent intervals throughout the course of septic shock. Beginning with increased cardiac index and oxygen delivery (Do2), which were the earliest observed hemodynamic changes, there were progressive increases in cardiac index, DO2, and VO2. The values of these variables in the survivors were both greater than normal and greater than those values of the nonsurvivors at comparable time periods. These values decreased in the late stage in nonsurvivors. There were early transient reductions in VO2 that preceded the increase in temperature and the decrease in blood pressure in both survivors and nonsurvivors. Although 86% of the septic patients were hyperdynamic, there were transient hypodynamic episodes (defined as cardiac index < 2.5 L/min/m2) in < 10% of the measurements. Transient preterminal hypermetabolic periods occurred in 9% of the nonsurvivors. CONCLUSIONS: Increased cardiac index and DO2 represent compensations for circulatory deficiencies that limit body metabolism, as reflected by inadequate VO2. Survivors have higher cardiac index, DO2, and VO2 values than those values of both the nonsurvivors and normal values. These data suggest that therapy should be directed toward increasing cardiac index to > 5.5 L/min/m2, DO2 to > 1000 mL/min/m2, and VO2 to > 190 mL/min/m2 as therapeutic goals; these supranormal values were empirically determined by the patterns of the survivors. Further studies to describe temporal relationships of biochemical mediators of these physiologic patterns are needed.

Adult↗
PubMed1993

Infection in minor gunshot wounds.

Of the 3684 patients enrolled in our study, 3390 were available for follow-up, of which 62 patients developed wound infections related to minor gunshot wounds (1.8%). Of these patients, all sustained entry/exit-type wounds while 60% of these patients sustained more than one injury. Complications were more likely to occur when a prolonged period occurred between the time of injury and the initial treatment. The development of infection in minor gunshot wound injuries is an unusual occurrence when these injuries are limited to the soft tissue structures. Additionally, wound debridement and antibiotics are often unnecessary in minor uncomplicated gunshot wounds, but may be beneficial in patients who have sustained multiple injuries, gross wound contamination, significant tissue devitalization, large wounds, or delay in treatment.

Adolescent↗
PubMed1993

Temporal hemodynamic and oxygen transport patterns in medical patients. Septic shock.

STUDY DESIGN: Because of the gradual insidious transitions between localized infection, generalized infection, and septic shock, it is difficult to compare data of patients in various stages and to differentiate primary from secondary and tertiary events. The aim of the present study was to describe the sequential pattern of hemodynamic and oxygen transport patterns of survivors and nonsurvivors of septic shock in order to evaluate possible physiologic mechanisms and to provide a template to relate the sequence of physiologic events to biochemical mediators. PROCEDURE: A previously described defined protocol was used prospectively to study the sequence of physiologic events using specific criteria to define stages as: (a) early period, the first recorded change in cardiac output; (b) middle period, time of maximal metabolic activity defined as the highest recorded oxygen consumption (VO2); and (c) late period, the time of death or recovery. In addition, three time lines were defined as the first time mean arterial pressure fell below 70 mm Hg, the first time temperature rose above 38 degrees C, and the earliest fall in VO2. Physiologic data were aligned in actual time before or after the time these criteria were met. Invasive hemodynamic and oxygen transport variables were measured with systemic and pulmonary artery catheters; intravascular pressures, arterial and mixed venous gas levels, cardiac output, and derived calculations were made at frequent intervals and keyed to the time of the cardiac output; each set of measurements in turn was keyed to the aforementioned time periods to describe the early, middle, and late periods. RESULTS: Beginning with increased cardiac index and oxygen delivery (DO2) as the early physiologic changes, there were progressive increases in cardiac index, DO2, and VO2 throughout the early and middle periods. They were maintained above the normal range in the late stage of survivors, but fell in the last 16 h in nonsurvivors. These values were greater in survivors than in nonsurvivors throughout. There were early transient reductions in VO2 that preceded the rise in temperature and the fall in mean arterial pressure (MAP). Although 84 percent of the septic patients were hyperdynamic, there were transient hypodynamic episodes defined as cardiac index of less than 2.5 L/min.m2 in approximately 10 percent of the measurements. There were also transient preterminal hypermetabolic periods in about 8 percent of the nonsurvivors. CONCLUSION: We conclude that increased cardiac index and DO2 represent compensations for circulatory inadequacies that limit body metabolism as reflected by VO2. Cardiac index, DO2, and VO2 values of survivors were higher than those of nonsurvivors and normal values. Therapy directed toward increasing cardiac index to supranormal values empirically determined by survivors has been reported to improve outcome. Additional studies to describe temporal relationships of biochemical mediators of these physiologic patterns are needed.

Analysis of Variance↗
PubMed1993

Hemodynamic and oxygen transport monitoring to titrate therapy in septic shock.

Traditionally, shock has been recognized or diagnosed by subjective signs and symptoms, particularly in septic shock, where transition from localized to systemic infection and then to septic shock may be gradual and subtle. Management has been directed toward normalizing these subjective symptoms as well as BP, heart rate, urine output, hematocrit, central venous pressure, and blood gases. The major problem is that restoration to normal values of these secondary aspects of shock do not correct the underlying tissue perfusion defect. The aim of this review is to describe a physiologic mechanistic model based on the concept that uneven vasoconstriction and maldistribution of flow are directly related to tissue hypoxia, oxygen debt, shock, shock-related organ failure, and death; second, to show that titration of therapy to optimal physiologic end-points using hemodynamic and oxygen transport monitoring is a potentially cost-effective therapeutic approach. This physiologic approach is based on the hypotheses that: a) the physiologic patterns of high-risk postoperative and septic survivors are significantly different from septic nonsurvivors; b) tissue perfusion can be evaluated by the sequential patterns of cardiac index, oxygen delivery (DO2), and oxygen consumption (VO2) measurements; c) the observed increased cardiac index and DO2 in the survivors are compensations that improve tissue oxygenation, which is reflected by the VO2 pattern; and d) the supranormal values that were documented in survivors provide objective physiologic criteria for therapeutic goals. The data suggest that a mechanistic analysis of the pathogenesis of shock may be elucidated by temporal patterns of the nonsurvivors' physiologic variables. That is, the predictive indices calculated for each variable quantitatively reflect the relationship of the early changes leading to death or survival. In essence, early changes in those variables statistically related to death may reflect pathogenic mechanisms, while early changes related to survival may be used as a first approximation to therapeutic goals. The application of this approach in prospective, randomized trials has demonstrated that prompt attainment of optimal goals (empirically defined from survivors' patterns) improved outcome in postoperative shock with and without sepsis, as well as in medical sepsis and accidental trauma. Specifically, when the optimal values of cardiac index, DO2, and VO2 used as therapeutic goals were attained in 8 to 12 hrs, there was marked and significant reduction in mortality and morbidity rates. This finding was also confirmed in 12 prospective, controlled trials, four of which were randomized. We conclude that driving septic shock patients into the survivors' patterns improves outcome, as has been shown in other shock syndromes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Temporal patterns of blood volume, hemodynamics, and oxygen transport in pathogenesis and therapy of postoperative adult respiratory distress syndrome.

Time relationships of physiologic patterns that are relevant to the pathogenesis of adult respiratory distress syndrome (ARDS) have not been well studied. The purpose of this review is to summarize the temporal relationship of blood volume, hemodynamics, and oxygen transport patterns occurring in postoperative patients before and after ARDS in order to develop a more complete mechanistic evaluation of its pathophysiology and to propose more rational therapeutic strategies. The data indicate that hypovolemia, reduced or uneven blood flow, inadequate delivery of oxygen, and insufficient consumption of oxygen precede the appearance of ARDS and are the primary precipitating physiologic events. This is contrary to conventional thinking which emphasizes capillary leak and fluid overload as the primary problems. The conventional approach also ignores events antecedent to ARDS that produce hypoxia of the lung tissue, result in pulmonary vasoconstriction, and increased pulmonary venous admixture (shunt). Therapy to prevent or rapidly treat these antecedent events has been shown to prevent or attenuate postoperative and posttraumatic ARDS. Various mediators such as interleukin (IL)-1, IL-6, and IL-8 and tumor necrosis factor as measured by plasma concentrations do not precede diagnostic criteria of ARDS, but may accelerate and augment the disorder as it is occurring.

Blood Volume↗
PubMed1992

Injury and violence in Los Angeles. Impact on access to health care and surgical education.

The Los Angeles County (California) Trauma Hospital System was designed to ensure that all patients requiring specialized trauma care would be transported directly to a trauma center using established trauma triage criteria. The designation and implementation of all level 1, 2, and 3 (rural) trauma centers were completed between October 1983 and July 1985. However, by February 1, 1985, one level 2 trauma center withdrew, and nine other level 2 and 3 trauma centers followed suit over the next few months and years. The reasons for closure of these 10 trauma centers were almost exclusively related to economic factors. The major impact of trauma center closure on surgical educational programs at the Drew University of Medicine and Science and the Martin Luther King, Jr/Charles R. Drew Medical Center have been additive and cumulative. The high volume of patients with trauma has been cited, sometimes correctly and sometimes incorrectly, as the primary reason for a lack of access to health care for patients without trauma. We have developed a blueprint for survival that, when fully implemented, will improve access to health care for all residents in our catchment area and optimize surgical education. While the Los Angeles County Trauma Hospital System has had many difficulties during the last 9 years, the population it serves is greater than that in 42 states in the United States. The experiences gained in Los Angeles County may be beneficial to statewide systems in the United States and in countries of comparable size.

General Surgery↗
PubMed1992

Role of oxygen debt in the development of organ failure sepsis, and death in high-risk surgical patients.

In a series of 253 high-risk surgical patients, we measured the oxygen consumption (VO2) at frequent intervals before, during, and immediately after surgical operations and calculated the rate of VO2 deficit from the measured VO2 minus the VO2 need estimated from the patient's own resting preoperative control values corrected for both temperature and anesthesia. The calculated oxygen deficit was related to multiple organ failure, complications, and outcome. The 64 patients who died all had organ failure; their cumulative VO2 deficit averaged 33.2 +/- 4.0 L/m2 (+/- SEM) at its maximum, which occurred 17.8 +/- 2.2 h after surgery. In the 31 survivors with organ failure, the cumulative VO2 deficit averaged 21.6 +/- 3.7 L/m2 at its maximum, which occurred 10.1 +/- 2.7 h after surgery (p less than 0.05). In the 158 survivors without organ failure or major complications, the maximum cumulative VO2 deficit averaged 9.2 +/- 1.3 L/m2 at 4.1 +/- 0.6 h after surgery (p less than 0.05). In a prospective randomized clinical trial, a protocol group maintained at supranormal hemodynamic and oxygen transport values had significantly reduced oxygen debt (7.6 +/- 3.4 L/m2 vs 17.3 +/- 6.8 L/m2; p less than 0.05), fewer organ failures, and lower mortality (4 percent vs 33 percent; p less than 0.05) compared with a control group maintained at normal hemodynamic values. The data demonstrate a strong relationship between the magnitude and duration of the VO2 deficit in the intraoperative and early postoperative period and the subsequent appearance of organ failure and death. The latter may be reduced when oxygen debts were prevented or minimized by augmenting naturally occurring compensations that increased oxygen delivery.

Adult↗