Biomedical subjects
Publications and source records attributed to Greg S Martin.
Shock is a broad category of injury to the human body caused by a variety of insults. Fluid resuscitation is the cornerstone of initial therapy for nearly all forms of shock. This article reviews the basic physiology determining body fluid composition, the goals of fluid resuscitation in shock, the types of fluids available for use, and clinical evidence for use of specific fluids based on etiology of the insult.
PURPOSE OF REVIEW: Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) affect hundreds of thousands of people each year worldwide, resulting in a significant healthcare burden. Over the past four decades, much has been discovered regarding the pathophysiology of lung injury, yet little progress has been made in advancing effective treatment strategies. In this article, we discuss the current knowledge as to fluid balance in the pathophysiology of ALI/ARDS and the recent innovations that have been described related to manipulations of hydrostatic or oncotic pressure in this condition. RECENT FINDINGS: Hypoproteinemia is a clear marker for ALI/ARDS and may play a pathophysiologic role given its independent prognostic value. Fluid balance and oncotic pressure alterations induced by diuretic and colloid therapy improve respiratory physiology and likely alter net flux of fluid across the injured capillary-alveolar membrane. Chest radiographs serve as a useful adjunctive tool in monitoring longitudinal fluid balance manipulations in ALI/ARDS. SUMMARY: Manipulation of Starling forces in established ALI/ARDS produces significant physiologic benefit and may influence outcome. Future research should focus on determining a mortality benefit with this readily available intervention.
OBJECTIVE: To ascertain the influence of albumin on antioxidant status in patients with acute lung injury. DESIGN: Prospective, randomized, placebo-controlled study. SETTING: Intensive care units, teaching hospitals. PATIENTS: Twenty patients meeting the American European Consensus criteria for acute lung injury. INTERVENTIONS: Ten patients received albumin (25 g of a 25% solution every 8 hrs for a total of nine doses) and ten received placebo (normal saline administered in identical fashion and volume). All received supportive therapy appropriate for patients with acute lung injury. Plasma samples were obtained sequentially from all patients before, 30 mins after, and 4 hrs after albumin/placebo administration. MEASUREMENTS AND MAIN RESULTS: Serum albumin and total protein, total antioxidant status, iron-binding antioxidant protection, iron-oxidizing antioxidant protection, lipid hydroperoxides, protein carbonyls, and plasma thiols were measured. Albumin administration increased plasma albumin concentrations (p <.05 compared with placebo) and decreased concentrations of protein carbonyls (p <.05 compared with placebo). By contrast, plasma lipid hydroperoxide concentrations were similar in both groups, both in absolute terms and relative to albumin content. For all other variables, no significant differences were apparent. For all patients, there was a positive correlation between albumin and plasma thiol concentrations (r =.983, p <.01) and albumin and antioxidant capacity (r =.885, p =.01). In the albumin treatment group, there was a strong correlation between thiols and antioxidant capacity (r =.876, p =.01). No such correlation was apparent in the placebo group. Plasma iron-binding antioxidant protection was negatively correlated (r = -.741, p <.05) with albumin content in the treatment group but not the placebo group. CONCLUSIONS: In patients with acute lung injury, albumin administration favorably influences plasma thiol-dependent antioxidant status as well as levels of protein oxidative damage.
BACKGROUND: Sepsis represents a substantial health care burden, and there is limited epidemiologic information about the demography of sepsis or about the temporal changes in its incidence and outcome. We investigated the epidemiology of sepsis in the United States, with specific examination of race and sex, causative organisms, the disposition of patients, and the incidence and outcome. METHODS: We analyzed the occurrence of sepsis from 1979 through 2000 using a nationally representative sample of all nonfederal acute care hospitals in the United States. Data on new cases were obtained from hospital discharge records coded according to the International Classification of Diseases, Ninth Revision, Clinical Modification. RESULTS: Review of discharge data on approximately 750 million hospitalizations in the United States over the 22-year period identified 10,319,418 cases of sepsis. Sepsis was more common among men than among women (mean annual relative risk, 1.28 [95 percent confidence interval, 1.24 to 1.32]) and among nonwhite persons than among white persons (mean annual relative risk, 1.90 [95 percent confidence interval, 1.81 to 2.00]). Between 1979 and 2000, there was an annualized increase in the incidence of sepsis of 8.7 percent, from about 164,000 cases (82.7 per 100,000 population) to nearly 660,000 cases (240.4 per 100,000 population). The rate of sepsis due to fungal organisms increased by 207 percent, with gram-positive bacteria becoming the predominant pathogens after 1987. The total in-hospital mortality rate fell from 27.8 percent during the period from 1979 through 1984 to 17.9 percent during the period from 1995 through 2000, yet the total number of deaths continued to increase. Mortality was highest among black men. Organ failure contributed cumulatively to mortality, with temporal improvements in survival among patients with fewer than three failing organs. The average length of the hospital stay decreased, and the rate of discharge to nonacute care medical facilities increased. CONCLUSIONS: The incidence of sepsis and the number of sepsis-related deaths are increasing, although the overall mortality rate among patients with sepsis is declining. There are also disparities among races and between men and women in the incidence of sepsis. Gram-positive bacteria and fungal organisms are increasingly common causes of sepsis.
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OBJECTIVE: Hypoproteinemia, fluid retention, and weight gain are associated with development of acute lung injury and mortality in critically ill patients, without proof of cause and effect. We designed a clinical trial to determine whether diuresis and colloid replacement in hypoproteinemic patients with acute lung injury would improve pulmonary physiology. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: All adult intensive care units from two university hospitals. PATIENTS: Thirty-seven mechanically-ventilated patients with acute lung injury and serum total protein </=5.0 g/dL. INTERVENTIONS: Five-day protocolized regimen of 25 g of human serum albumin every 8 hrs with continuous infusion furosemide, or dual placebo, targeted to diuresis, weight loss, and serum total protein. MEASUREMENTS AND MAIN RESULTS: Measured outcomes included change in weight, serum total protein, fluid balance, hemodynamics, respiratory system compliance, and oxygenation. Baseline characteristics were similar between groups (treatment, n = 19; control, n = 18), with trauma being the major cause of acute lung injury. Diuresis and weight loss over 5 days (5.3 kg more in the treatment group, p =.04) was accompanied by improvements in the Pao2/Fio2 ratio in the treatment group within 24 hrs (from 171 to 236, p =.02). Respiratory mechanics were unchanged. Mean arterial pressure increased from 80 to 88 mm Hg (p =.10), and heart rate decreased from 110 to 95 beats/min (p =.008) over time in the treatment group. No difference in mortality was observed, with favorable trends in measures of intensive care. CONCLUSIONS: Albumin and furosemide therapy improves fluid balance, oxygenation, and hemodynamics in hypoproteinemic patients with acute lung injury. Determining the effect of this simple therapy on cost, outcomes, and other patient populations requires further study.
STUDY OBJECTIVES: Fluid balance concerns occur daily in critically ill patients, complicated by difficulties assessing intravascular volume. Chest radiographs (CXRs) quantify pulmonary edema in acute lung injury (ALI) and total blood volume in normal subjects. We hypothesized that CXRs would reflect temporal changes in fluid balance in critically ill patients. DESIGN: Standardized scoring of 133 supine, portable, anteroposterior CXRs. Outcomes included subjective and objective measures of intravascular volume and pulmonary edema. SETTING: Academic university medical center and affiliated Veterans Affairs hospital. PATIENTS: Thirty-seven patients with ALI receiving mechanical ventilation blindly randomized to treatment with diuretics and colloids or dual placebo for 5 days. MEASUREMENTS AND RESULTS: Treated patients experienced a 3.3-L diuresis and 10-kg weight loss during the 5-day period. A significant correlation was observed in all patients between changes in vascular pedicle width (VPW) and net intake/output (r = 0.50, p = 0.01) or weight (r = 0.51, p = 0.01). The correlation between VPW and fluid balance was greatest for weight changes in the treatment group alone (r = 0.71, p = 0.005). Pulmonary artery occlusion pressure correlated highly with changes in VPW (r = 0.70, p < 0.001). After day 1, CXRs revealed significant between-group differences in VPW without changes in cardiothoracic ratio or subjective measures of edema. The proportion of patients with VPW < 70 mm did not differ at baseline but was significantly more in the treatment group on all subsequent days (p < 0.05). CONCLUSIONS: We conclude that temporal fluid balance changes are reflected on commonly utilized portable CXRs. Objective radiographic measures of intravascular volume may be more appropriate indicators of fluid balance than subjective measures, with VPW appearing most sensitive. If systematically quantitated, serial CXRs provide a substantial supplement to other clinically available data for the purpose of fluid management in critically ill patients.