David E. Skarda

Dynamic near-infrared spectroscopy measurements in patients with severe sepsis.

This study evaluated near-infrared spectroscopy (NIRS)-derived measurements in hemodynamically stable patients with severe sepsis, as compared with similar measurements in healthy age-matched volunteers. Prospective, preliminary, observational study in a surgical intensive care unit and clinical research center at a university health center. We enrolled 10 patients with severe sepsis and 9 healthy age-matched volunteers. For patients with severe sepsis, we obtained pulmonary artery catheter and laboratory values three times daily for 3 days and oxygen consumption values via metabolic cart once daily for 3 days. For healthy volunteers, we obtained all noninvasive measurements during a single session. We found lower values in patients with severe sepsis (versus healthy volunteers), in tissue oxygen saturation (StO2), in the StO2 recovery slope, in the tissue hemoglobin index, and in the total tissue hemoglobin increase on venous occlusion. Patients with severe sepsis had longer StO2 recovery times and lower NIRS-derived local oxygen consumption values versus healthy volunteers. In our preliminary study, NIRS provides a noninvasive continuous method to evaluate peripheral tissue oxygen metabolism in hemodynamically stable patients with severe sepsis. Further research is needed to demonstrate whether these values apply to broader populations of patients with systemic inflammatory response syndrome, sepsis, severe sepsis, and septic shock.

Lymphatic tissue fibrosis is associated with reduced numbers of naive CD4+ T cells in human immunodeficiency virus type 1 infection.

ABSTRACT The organized structure of lymphatic tissues (LTs) constitutes a microenvironment referred to as a niche that plays a critical role in immune system homeostasis by promoting cellular interactions and providing access to cytokines and growth factors on which cells are dependent for survival, proliferation, and differentiation. In chronic human immunodeficiency virus type 1 (HIV-1) infection, immune activation and inflammation result in collagen deposition and disruption of this LT niche. We have previously shown that these fibrotic changes correlate with a reduction in the size of the total population of CD4+ T cells. We now show that this reduction is most substantial within the naïve CD4+ T-cell population and is in proportion to the extent of LT collagen deposition in HIV-1 infection. Thus, the previously documented depletion of naïve CD4+ T cells in LTs in HIV-1 infection may be a consequence not only of a decreased supply of thymic emigrants or chronic immune activation but also of the decreased ability of those cells to survive in a scarred LT niche. We speculate that LT collagen deposition might therefore limit repopulation of naïve CD4+ T cells with highly active antiretroviral therapy, and thus, additional treatments directed to limiting or reversing inflammatory damage to the LT niche could potentially improve immune reconstitution.

Amount of lymphatic tissue fibrosis in HIV infection predicts magnitude of HAART-associated change in peripheral CD4 cell count.

The structure of lymphatic tissues is an important component of lymphatic tissue T-cell homeostasis. Collagen deposition in lymphatic tissues (common in HIV infection) disrupts the niche and limits the size of the resident CD4 cell population. In this report we show that a single measurement of lymphatic tissue collagen predicts the magnitude of recovery of the peripheral CD4 cell pool with HAART (P < 0.001). This suggests that collagen-targeted therapies might be of benefit.

Hyperbaric oxygen does not improve outcome in patients with necrotizing soft tissue infection.

BACKGROUND Patients with necrotizing soft tissue infections (NSTIs) require prompt surgical debridement, appropriate intravenous antibiotics, and intensive support. Despite aggressive treatment, their mortality and morbidity rates remain high. The benefit of hyperbaric oxygen (HBO) as an adjunctive treatment is controversial. We investigated the effect of HBO in treating NSTIs. METHODS We analyzed clinical data retrospectively for 78 patients with NSTIs: 30 patients at one center were treated with surgery, antibiotics, and supportive care; 48 patients at a different center received adjunctive HBO treatment. We compared the two groups in terms of demographic characteristics, risk factors, NSTI microbiology, and patient outcomes. To identify variables associated with higher mortality rates, we used logistic regression analysis. RESULTS Demographic characteristics and risk factors were similar in the HBO and non-HBO groups. The mean patient age was 49.5 years; 37% of the patients were female, and 49% had diabetes mellitus. Patients underwent a mean of 3.0 excisional debridements. The median hospital length of stay was 16.5 days; the median duration of antibiotic use was 15.0 days. In 36% of patients, cultures were polymicrobial; group A Streptococcus was the organism most commonly isolated (28%). We identified no statistically significant differences in outcomes between the two groups. The mortality rate for the HBO group (8.3%) was lower, although not significantly different (p = 0.48), than that observed for the non-HBO group (13.3%). The number of debridements was greater in the HBO group (3.0; p = 0.03). The hospital length of stay and duration of antibiotic use were similar for the two groups. Multivariable analysis showed that hypotension on admission and immunosuppression were significant independent risk factors for death. CONCLUSIONS Adjunctive use of HBO to treat NSTIs did not reduce the mortality rate, number of debridements, hospital length of stay, or duration of antibiotic use. Immunosupression and early hypotension were important risk factors associated with higher mortality rates in patients with NSTIs.

Near-Infrared Spectroscopy in Patients with Severe Sepsis: Correlation with Invasive Hemodynamic Measurements

BACKGROUND Clinicians have begun using near-infrared spectroscopy (NIRS) to monitor tissue perfusion in hemorrhagic shock, as the technique allows continuous noninvasive monitoring of tissue hemoglobin oxygen saturation (StO(2)) and the tissue hemoglobin index (THI). We hypothesized that StO(2) measurements in patients with severe sepsis would be associated with the severity of their illness and would correlate with invasive hemodynamic measurements. METHODS We measured mean arterial pressure (MAP), serum lactate concentration, blood hemoglobin concentration, StO(2), and THI in nine healthy volunteers and ten patients with septic shock in a surgical intensive care unit (ICU). Enrolled patients had a pulmonary artery catheter, and had family able to give informed consent. The average Acute Physiology and Chronic Health Evaluation (APACHE) II score at enrollment for the patients was 19 +/- 5 (standard deviation) points. Volunteers and patients were similar with respect to age and sex. To collect NIRS data, we used the InSpectra Tissue Spectrometer, Model 325 (Hutchinson Technology, Inc., Hutchinson, MN). For three consecutive days, we obtained invasive hemodynamic measurements three times daily, simultaneously with NIRS measurements, and metabolic cart measurements once daily. RESULTS Patients with severe sepsis had significantly lower thenar muscle StO(2) values (p = 0.031) than healthy volunteers. Near-infrared spectroscopy-derived mixed venous oxygen saturation (NIRSvO(2)) and StO(2) measured from the thenar eminence in patients with severe sepsis correlated with SvO(2) from the pulmonary artery catheter (p < 0.05). In this group of patients, StO(2) did not correlate significantly with lactate concentration, base deficit, or APACHE II score. CONCLUSIONS Near-infrared spectroscopic measurements of StO(2) correlated with invasive hemodynamic measurements in patients with severe sepsis but did not correlate with severity of illness. These findings suggest that NIRStO(2) may be a clinically useful measurement in monitoring patients with severe sepsis. Further study of this device in early resuscitation of patients with sepsis is necessary.

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 Ringers (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 (StO2) 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 StO2 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.

Charge Awareness Affects Treatment Choice: Prospective Randomized Trial in Pediatric Appendectomy.

OBJECTIVE To determine whether charge awareness affects patient decisions. BACKGROUND Pediatric uncomplicated appendicitis can be treated with open or laparoscopic techniques. These 2 operations are considered to have clinical equipoise. METHODS In a prospective, randomized clinical trial, nonobese children admitted to a childrens hospital with uncomplicated appendicitis were randomized to view 1 of 2 videos discussing open and laparoscopic appendectomy. Videos were identical except that only one presented the difference in surgical materials charges. Patients and parents then choose which operation they desired. Videos were available in English and Spanish. A postoperative survey was conducted to examine factors that influenced choice. The trial was registered at ClinicalTrials.gov (NCT 01738750). RESULTS Of 275 consecutive cases, 100 met enrollment criteria. In the group exposed to charge data (n = 49), 63% chose open technique versus 35% not presented charge data (P = 0.005). Patients were 1.8 times more likely to choose the less expensive option when charge estimate was given (95% confidence interval, 1.17-2.75). The median total hospital charges were

Death Caused by Splenic Artery Aneurysm Rupture during Dobutamine–Atropine Stress Echocardiography: Case Report and Literature Review

1554 less for those who had open technique (P < 0.001) and

Upper aerodigestive injuries from detergent ingestion in children.

528 less for the group exposed to charge information (P = 0.033). Survey found that 90% of families valued having input in this decision and 31% of patients exposed to charge listed it as their primary reason for their choice in technique. CONCLUSIONS Patients and parents tended to choose the less expensive but equally effective technique when given the opportunity. A discussion of treatment options, which includes charge information, may represent an unrealized opportunity to affect change in health care spending.

Surgical Safety Checklists in Children’s Surgery: Surgeons’ Attitudes and Review of the Literature

A 55‐year‐old man developed hypertension and acute epigastric pain during dobutamine–atropine stress echocardiography (DASE). Evaluation—including a helical computed tomography (CT) scan of the abdomen and pelvis, as well as surgical exploration—revealed a ruptured splenic artery aneurysm. The patient died, despite multiple surgical interventions and a massive blood product transfusion. Impressively, no deaths from DASE have been previously reported. Additionally, no adverse sequelae during DASE have been reported in patients with an unruptured abdominal aortic aneurysm ≥4 cm in diameter or with an unruptured intracranial aneurysm. We report the first case, to our knowledge, of death caused by splenic artery aneurysm rupture during DASE. Splenic artery aneurysm rupture during DASE, though rare, can lead to death.