A wide gap second derivative NIR spectroscopic method for measuring tissue hemoglobin oxygen saturation.
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Animals↗
Biomedical subjects
Greg J Beilman
Publications and source records attributed to Greg J Beilman.
Practical considerations for glucose control in hospitalized patients.
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Blood Glucose↗
Hyperglycemia in the intensive care unit: no longer just a marker of illness severity.
BACKGROUND: Hyperglycemia is a common occurrence in critically ill patients. Recent evidence has demonstrated improved survival in patients in surgical intensive care units (SICUs) receiving "tight glycemic control." The mechanisms of this survival advantage are not well understood. METHODS: A review of the English language literature pertaining to potential mechanisms affecting outcome in critically ill patients receiving insulin therapy, including recently published human trials evaluating mortality outcomes. RESULTS: This review discusses the results of clinical trials of "tight glycemic control," considers mechanisms of hyperglycemia in critical illness, and reviews potential mechanisms of improved outcome related in the critically ill patient. CONCLUSIONS: A number of human studies have demonstrated improved outcomes in critically ill patient populations receiving insulin therapy with a target of euglycemia, suggesting at least part of the benefit of this therapy is normal blood sugar and not the effects of insulin. An important population not studied to date is patients in the medical ICU. However, aggressive control of hyperglycemia now remains an important component of care for all surgical patients in the ICU.
Critical Care↗
Abdominal complications of ventricular assist device placement.
BACKGROUND: Ventricular assist devices (VADs) provide a bridge to transplantation for patients awaiting heart transplant. Because of its intra-abdominal placement, the potential exists for major abdominal complications. The purpose of this study is to identify VAD-associated abdominal complications and their incidence, and to describe preventive measures. METHODS: Records of patients having had VAD placement were identified from our registry from April 12, 1995, when the first VAD placement occurred, to July 15, 2003. Each patient was evaluated for the occurrence of an abdominal complication, defined as mechanical small bowel obstruction, infection with an abdominal source, hernia, or other abdominal pathology occurring after VAD placement. RESULTS: One hundred twenty-four VADs were implanted in 100 patients. Of these patients, 82 received one VAD, 13 received two devices, four received three devices, and one patient received four devices. Twelve abdominal complications occurred in 11 patients (11%). There was a 36% (4/11) pre-transplant mortality rate in patients with an abdominal complication, compared to 17% (15/89) pre-transplant mortality in patients without an abdominal complication (p = 0.21). Three of five patients with abdominal infection died. CONCLUSIONS: Abdominal complications after VAD placement are common. Intra-abdominal VAD infection is the most common and serious complication, leading to a mortality rate of 60% in our population. Additionally, small bowel obstructions, incisional and inguinal hernias, acalculous cholecystitis, and pancreatitis also occurred. Appropriate preventive measures may decrease the risk of developing many of these complications.
Abdomen↗
Emerging infections with community-associated methicillin-resistant Staphylococcus aureus in outpatients at an Army Community Hospital.
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infection typically occurs in chronically ill patients requiring long-term antimicrobial therapy or hospitalization. However, community-associated MRSA (CA-MRSA) necrotizing soft tissue infections seem to be increasing in incidence. Our aim was to describe the incidence and microbiologic characteristics of CA-MRSA isolates collected at an army community hospital. METHODS: We report a retrospective review of MRSA isolates identified during 1998-2003 at the microbiology laboratory of Moncrief Army Community Hospital that serves a community of approximately 40,000 transient residents yearly in Fort Jackson, South Carolina. We evaluated the incidence of MRSA in our laboratory during 1998-2003. For MRSA isolates from 2003, we evaluated antimicrobial susceptibility patterns. Six selected isolates were evaluated by molecular typing, resistance gene analysis, and toxin analysis. RESULTS: During 1998-2003, 241 (23%) of 1041 S. aureus isolates identified at the hospital microbiology laboratory were resistant to methicillin. Of these 241 MRSA isolates, 223 were cultured from outpatients. The incidence of MRSA in our population increased from 12% of S. aureus isolates in 1998 to 43% in 2003. In 2003, MRSA was cultured from 76 different patients. Isolates of MRSA were often resistant to erythromycin (91%), although resistance to other agents was less common: Ciprofloxacin (14%), levofloxacin (14%), clindamycin (3%), tetracycline (3%), and trimethoprim sulfamethoxazole (1%). No isolates were resistant to vancomycin, gentamicin, nitrofurantoin, or rifampin. Six CA-MRSA isolates were compared by pulsed-field gel electrophoresis (PFGE). Five were PFGE type USA300, and one was PFGE type USA100, based on the U.S. Centers for Disease Control and Prevention (CDC) classification scheme. The five USA300 isolates carried SCCmec type IV, and the USA100 carried SCCmec II. None of the isolates were positive by PCR for genes encoding enterotoxins A-E and H, or toxic shock syndrome toxin (TSST-1), but the five USA300 isolates carried the gene coding for Panton-Valentine leukocidin toxin. CONCLUSIONS: The incidence of MRSA at our institution is increasing. Isolates of MRSA show resistance patterns and microbiologic characteristics consistent with CA-MRSA isolates from the United States. Clinicians should consider the possibility of CA-MRSA in patients with soft-tissue infections who do not respond to initial therapy with beta-lactam antimicrobial agents.
Community-Acquired Infections↗
Use of near-infrared spectroscopy in early determination of irreversible hemorrhagic shock.
BACKGROUND: In field situations, patient triage may require early determination of patients progressing to irreversible shock. We investigated the utility of near-infrared spectroscopy (NIRS) in early detection of irreversible hemorrhagic shock. METHODS: Twenty instrumented pigs were treated with a protocol involving 35% blood volume hemorrhage, 90 minutes of shock, and stepwise resuscitation with lactated Ringer's. Hemodynamics and NIRS measurements of skeletal muscle (leg), stomach, and liver tissue oxyhemoglobin saturation (StO2) were measured at baseline, every 30 minutes during shock, and after each resuscitative step. Measurements were compared between animals that expired during resuscitation (unresuscitatable) and animals that survived all resuscitative steps (resuscitatable). RESULTS: Neither global oxygen delivery, oxygen consumption, nor lactate distinguished resuscitatable from unresuscitatable animals. Invasive measurements of SvO2 did distinguish resuscitatable from unresuscitatable animals. After the first fluid bolus, both stomach and leg StO2 differed significantly between resuscitatable and unresuscitatable animals. Regression analysis revealed skeletal muscle (leg) StO2 obtained after the first resuscitative step was a significant mortality predictor despite resuscitation (r2=0.45) (p = 0.005). CONCLUSIONS: Non-invasive NIRS monitoring of leg and stomach StO2 differentiates resuscitatable from unresuscitatable animals after the initial resuscitative bolus. Use of this non-invasive tool may guide appropriate use of resuscitative fluids and has possible point-of-care applications.
Animals↗
Ringer's ethyl pyruvate in hemorrhagic shock and resuscitation does not improve early hemodynamics or tissue energetics.
Reactive oxygen species (ROS) have been implicated in the pathogenesis of hemorrhagic shock. Ethyl pyruvate, a derivative of pyruvate and a proposed oxygen radical scavenger, is attractive as a possible resuscitation fluid. We investigated whether resuscitation with lactated Ringer's (LR) containing ethyl pyruvate (REP) had any hemodynamic or tissue energetic benefits compared with LR alone for hemorrhagic shock. Hemorrhagic shock was induced in splenectomized pigs via inferior vena cava cannula. After 90 min of shock, animals were resuscitated in a stepwise fashion with LR or REP (30 mg/kg/dose, given as 1.5 mg/mL in LR) at 20 cc/kg/step for four steps. Data collected during this experiment included physiologic and hemodynamic parameters, near-infrared reflectance spectroscopy measurements of tissue hemoglobin oxygen (StO(2)) of the stomach, liver, and hind limb, and nuclear magnetic resonance phosphorus spectra of the liver and hind limb at each time point. In both resuscitative groups, heart rate, and lactate and pyruvate values increased during shock and began to drop toward baseline values during resuscitation. Mean arterial pressure, oxygen delivery, and oxygen consumption decreased during shock and increased toward baseline levels during the resuscitative process. There were no significant changes in physiologic parameters between the LR- and REP-resuscitated animals. There was a significantly lower stomach StO(2) and hind limb cellular cytoplasmic pH during later resuscitative endpoints in REP-resuscitated animals. The clinical significance of these findings are unclear. There is no short-term hemodynamic or tissue energetic advantage to using REP as a resuscitation fluid when compared with LR. Long-term outcome studies are needed to further evaluate any potential benefits of use of REP in hemorrhagic shock.
Adenosine Triphosphate↗
Population-based prediction of trauma volumes at a Level 1 trauma centre.
OBJECTIVE: With an ageing US population, the demographics of traumatic injuries are being significantly altered. Census projections predict that the number of Americans over age 65 will double in the next 20 years. We used stochastic methods to forecast trauma admissions in order to predict the effects of such demographic changes at our trauma centre. METHODS: Age- and sex-related rates of traumatic admission were determined using population statistics and trauma registry data from 1994 to 1999. These rates were then projected from 2000 to 2025 based on both the Lee-Carter and random walk with drift methods. Stochastic population projections were made and paired with the projected trauma rates, allowing estimation of total trauma volume. RESULTS: Trauma rates were predicted to increase for most age groups. Trauma admissions are predicted to increase 57% by 2024. By 2019, 50% of trauma admissions will be 60 or older. CONCLUSIONS: Our trauma volume is expected to increase 57% by 2024, an increase of 2% per year. More of this volume will consist of elderly patients, potentially requiring increased health-care resources.
Adolescent↗
New strategies to improve outcomes in the surgical intensive care unit.
BACKGROUND: Over the last half-decade, substantial breakthroughs have taken place in terms of routine therapy of critically ill patients. The combination of these strategies has the potential to result in improvement in the overall outcomes for patients in intensive care units. METHODS: A focused review was undertaken of trials of interventions in critically ill patients with outcome endpoints. RESULTS: This review discusses recent results related to transfusion avoidance, new drug therapy of sepsis, low tidal volume ventilation, tight glycemic control, early goal-directed resuscitation in sepsis, and the contribution of intensivists to improved outcomes. CONCLUSIONS: Appropriate incorporation of these strategies into everyday practice will likely result in improvements in the care of critically ill surgical patients.
Adrenal Cortex Hormones↗
Tissue energetics as measured by nuclear magnetic resonance spectroscopy during hemorrhagic shock.
The defect in energy production in an organism during shock states may be related to the impairment of mitochondrial respiration early in shock. The aim of this study was to investigate the timing and degree of cellular energetic changes during hemorrhagic shock in real time. Instrumented, splenectomized swine were randomized to undergo hemorrhagic shock, induced by a 35% blood volume bleed, for 90 min with (n = 10) or without (n = 9) subsequent resuscitation. Resuscitated animals received shed blood in two increments followed by two normal saline boluses (20 mL/kg/bolus). Throughout experimentation, tissue phosphoenergetics of liver and skeletal muscle were monitored using 31P nuclear magnetic resonance (NMR) spectroscopy via NMR coils on the liver and hindlimb. Near-infrared spectroscopy probes were used to measure liver, stomach, and skeletal muscle oxyhemoglobin saturation (StO2). Hemorrhagic shock induced an increase in phosphomonoesters in skeletal muscle (baseline: 7.09%, 90 min: 9.94% (P < 0.05); expressed as percent total phosphorus). This increase resolved in animals receiving resuscitation (n = 10) but remained elevated in those in unresuscitated shock (n = 9). Inorganic phosphate levels increased and betaATP levels decreased significantly in the liver of animals in shock as compared with baseline. StO2 in skeletal muscle, stomach, and liver correlated with whole organism oxygen delivery (r2 = 0.356, 0.368, and 0.432, respectively). We conclude that hemorrhagic shock induces early elevation of phosphomonoesters in skeletal muscle, which correlates with the severity of shock. This implies an early transition to anaerobic glycolysis during hemorrhagic shock, which may be indicative of early mitochondrial dysfunction.
Adenosine Triphosphate↗
Early surgery for thoracolumbar spine injuries decreases complications.
BACKGROUND: The proper timing for surgical fracture repair is controversial. Early repair of long bone and cervical fractures reduces complications and is safe. Few studies exist to compare time to surgery with outcomes in thoracolumbar (TL) spine injuries. METHODS: Patients with TL spine injuries were identified from the trauma registry and divided into two cohorts on the basis of Injury Severity Score (ISS). Cohorts were compared for infectious, respiratory, and total complications in patients who had early (<72 hours from injury) versus late (>72 hours from injury) surgical repair. A retrospective chart review was performed on High ISS patients (> or =15) to identify differences in resuscitation needs and neurologic, respiratory, and infectious complications. RESULTS: Early surgery, Low ISS patients were younger, received fewer anterior repairs, and had shorter hospitalizations. Early patients in the High ISS cohort had significantly fewer total complications and shorter hospital and intensive care unit lengths of stay. Resuscitative requirements were similar for both surgery groups. More late surgery patients required ventilator support for noninfectious reasons. There was no difference in admission or postoperative neurologic status or the incidence of head injury. CONCLUSION: Early surgery in severely injured patients with thoracolumbar spine trauma was associated with fewer complications and shorter hospital and intensive care unit lengths of stay, required less ventilator support for noninfectious reasons, and did not increase neurologic deficits.
Adult↗
Phosphomonoesters predict early mortality in porcine hemorrhagic shock.
BACKGROUND: Hemodynamic, laboratory, and tissue energetics were measured in a porcine model of hemorrhagic shock to evaluate variables as predictors of early mortality from shock. We hypothesized that elevated phosphomonoesters would predict early mortality in hemorrhagic shock. METHODS: Pigs (n = 36) were subjected to 35% hemorrhage for 90 minutes in a 1.5-T nuclear magnetic resonance (NMR) magnet. Measurements included base deficit (BD); lactate; oxygen consumption/delivery; near-infrared spectroscopy of liver, stomach, and skeletal muscle tissue oxyhemoglobin saturation; and NMR spectroscopic measurements of high-energy phosphates of liver and skeletal muscle. Variables were compared between nonsurvivors and survivors to resuscitation after 90-minute measurements. RESULTS: Ninety-minute mortality was 25%. Muscle phosphomonoesters (PMEs) and oxygen consumption differed significantly between survivors and nonsurvivors at baseline. Regression analysis identified baseline muscle PME levels, baseline BD, and 30-minute BD as early predictors of mortality before resuscitation (r2 = 0.304). CONCLUSION: Baseline elevation in muscle PME levels predicts mortality in an animal model of severe hemorrhagic shock.
Acid-Base Imbalance↗
Mononuclear cell function and energetics in early traumatic injury.
BACKGROUND: The reason for increased infectious complications after traumatic injury is complex and incompletely understood. We propose a relationship between the energetic state of circulating immune cells and immune cell function in traumatic injury. To examine this relationship, cellular adenosine triphosphate (ATP) concentration and cellular functions were measured in peripheral blood mononuclear cells from trauma patients and normal subjects. MATERIALS AND METHODS: Mononuclear cells were isolated within 24 h of injury from trauma patients without (n = 12) or with (n = 10) hypotension (groups 1 and 2, respectively), and a group of normal control subjects (group 3, n = 13). Mononuclear cells were assayed for ATP levels using bioluminescence. Phagocytosis was quantified via flow cytometry after ingestion of fluorescent microspheres and phagocytic index (PI) was calculated (average number of particles ingested per monocyte). Protein synthesis was quantified using incorporation of (35)S-labeled methionine into cultured cells. Comparisons between groups were performed using one-way analysis of variance (ANOVA) with adjustment for multiple comparisons. RESULTS: All but one trauma patient suffered blunt injury. There were significantly more transfusions in group 2 (hypotensive) patients (p = 0.0005). Nosocomial infections, length of stay (LOS), and mortality did not differ between groups 1 and 2. Concentrations of ATP and PI in both groups of traum a patients did not significantly differ from controls. In hypotensive trauma patients, increased duration of hypotension was associated with increased mononuclear cell ATP levels (r(2) = 0.227). A negative correlation between PI and ATP levels in trauma patients was discovered. Incorporation of (35)S was significantly greater in normotensive trauma patients than controls. CONCLUSION: Mononuclear cell ATP levels and measured functions are preserved in early traumatic injury.
Adenosine Triphosphate↗
Moderately elevated serum troponin concentrations are associated with increased morbidity and mortality rates in surgical intensive care unit patients.
OBJECTIVE: To determine the significance of moderate elevations of serum troponin I in a surgical intensive care unit patient population in terms of its impact on indexes of outcome including mortality, morbidity, and hospital and intensive care unit length of stay. DESIGN: Retrospective chart review and analysis of clinical data. SETTING: A surgical intensive care unit at a tertiary care hospital. PATIENTS: From the 27-month surgical intensive care unit database of admissions, 869 patients with serum troponin I determinations during their admission were identified. Patients who had cardiac surgery were excluded. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Patients were divided into four groups based on their maximum serum troponin I concentrations. Hospital mortality, incidence of myocardial infarction, and hospital and intensive care unit length of stays were compared. Patients with moderate elevations of serum troponin I (0.4-2.0 microg/L) had a significantly higher mortality rate (chi-square = 32.57, p <.0001) and longer length of intensive care unit and hospital stays (p <.0005) when compared with patients without similar elevations. Within the range of moderately elevated troponin concentrations, higher titers were associated with increasing mortality risk, longer hospital and intensive care unit stays, and a higher incidence of myocardial infarction. The use of a beta-blocker and aspirin was associated with better survival for patients with maximum serum troponin concentrations > or =2 microg/L. CONCLUSION: Moderate elevations of serum troponin I, which are below the threshold required to diagnose overt myocardial infarction, may reflect ongoing myocardial injury in the critically ill and are associated with a higher mortality rate and longer hospital and intensive care unit length of stays. The use of beta-blockers and aspirin is associated with better outcomes for this subset of patients.
Adrenergic beta-Antagonists↗
Hypokalemia following trauma.
Frequent hypokalemia was noted immediately after trauma, and it was hypothesized that hypokalemia occurred more frequently in the more severely injured. A retrospective trauma registry and chart review was done on 546 trauma patients looking at admission potassium, a variety of lab tests related to potassium, specific injuries, hospital/ICU lengths of stay, and general patient demographics. Admission hypokalemia (K < 3.6 meq/l) was more frequent in those with closed head injuries (41.1% vs. 27.5%, P < .001) and in those who suffered spinal cord injuries (54.5% vs. 33.6%, P < .05). Hyperglycemia was more frequent with admission hypokalemia (45.2% vs. 29.7%, P < .001). Hypokalemia occurred more frequently in younger patients (28.6 vs. 37.7 y, P < .001). Also, the pediatric group, ages 5-14, had admission hypokalemia more frequently than those ages 15-59, or those ages > 59 (54.9% vs. 34.5% vs. 16.7%, P < .001). Glasgow Coma Scores (GCS) were significantly lower (12.0 vs. 13.5, P < .001) and Injury Severity Scores (ISS) were higher (17.4 vs. 13.4, P < .001), with admission hypokalemia. Additionally, hypokalemia was a positive predictor of ISS (P = .05). Hypokalemic patients more likely needed a ventilator, (26.6% vs. 16.5%, P < .01) but did not have significantly more ventilator days (P > .05). Subsequently, hypokalemic patients had longer ICU lengths of stay (LOS) (2.6 vs. 1.5 days, P < .005) and longer hospital LOS (8.5 vs. 5.6 days, P < .001). When stratified into categories of "severe": (K < 3.1 meq/l), "moderate": (K = 3.1-3.3 meq/l), and "mild": (K = 3.4-3.5 meq/l) hypokalemia, those with severe hypokalemia had significantly lower GCS (10.0 vs. 13.1, p < .05), higher serum glucose levels (167 vs. 137 mg/dl, P < .05), lower creatinine levels (.77 vs. .95 mg/dl, P < .05), and longer hospital lengths of stay (13.1 days vs. 7.6 days, P < .05 results).
Adolescent↗
Sigmoidoscopy-assisted colostomy--an adapted trephine stoma formation.
BACKGROUND/AIM: The purpose of this article was to report an adapted colostomy procedure that can be used on patients with multiple morbidities requiring fecal diversion. METHODS: An adapted colostomy was performed on a patient needing fecal diversion who had multiple surgical and medical complications. RESULTS: Thirteen weeks after colostomy placement, the patient's colostomy functioned well and was viable throughout his course without related complications. CONCLUSION: The method of sigmoidoscopy-assisted colostomy described here can be beneficial to the complicated patient needing fecal diversion but unable to tolerate a laparotomy or laparoscopy.
Aged↗
Noninvasive method for measuring local hemoglobin oxygen saturation in tissue using wide gap second derivative near-infrared spectroscopy.
A simple continuous wave near-infrared algorithm for estimating local hemoglobin oxygen saturation in tissue (%StO2) is described using single depth attenuation measurements at 680, 720, 760, and 800 nm. Second derivative spectroscopy was used to reduce light scattering effects, chromophores with constant absorption, baseline/instrumentation drift, and movement artifacts. Unlike previous second derivative methods which focused primarily on measuring deoxyhemoglobin concentration; a wide 40 nm wavelength gap used for calculating second derivative attenuation significantly improved sensitivity to oxyhemoglobin absorption. Scaled second derivative attenuation at 720 nm was correlated to in vitro hemoglobin oxygen saturation to generate a %StO2 calibration curve. The calibration curve was insensitive to total hemoglobin, optical path length, and optical scattering. Measurement error due to normal levels of carboxyhemoglobin, methemoglobin, and water absorption were less than 10 %StO2 units. Severe methemoglobinemia or edema combined with low blood volume could cause StO2 errors to exceed 10 StO2 units. Both a broadband and commercial four-wavelength spectrometer (InSpectra) measured %StO2. The InSpectra tissue spectrometer readily detected limb ischemia on 26 human volunteers for hand, forearm, and leg muscles. A strong linear correlation, r2>0.93, between StO2 and microvascular %SO2 was observed for isolated animal hind limb, kidney, and heart.
Adult↗