Immediate Norepinephrine in Endotoxic Shock: Effects on Regional and Microcirculatory Flow.

OBJECTIVES: To investigate the effects of immediate start of norepinephrine versus initial fluid loading followed by norepinephrine on macro hemodynamics, regional splanchnic and intestinal microcirculatory flows in endotoxic shock. DESIGN: Animal experimental study. SETTING: University translational research laboratory. SUBJECTS: Fifteen Landrace pigs. INTERVENTIONS: Shock was induced by escalating dose of lipopolysaccharide. Animals were allocated to immediate start of norepinephrine (i-NE) ( n = 6) versus mandatory 1-hour fluid loading (30 mL/kg) followed by norepinephrine (i-FL) ( n = 6). Once mean arterial pressure greater than or equal to 75 mm Hg was, respectively, achieved, successive mini-fluid boluses of 4 mL/kg of Ringer Lactate were given whenever: a) arterial lactate greater than 2.0 mmol/L or decrease less than 10% per 30 min and b) fluid responsiveness was judged to be positive. Three additional animals were used as controls (Sham) ( n = 3). Time × group interactions were evaluated by repeated-measures analysis of variance. MEASUREMENTS AND MAIN RESULTS: Hypotension was significantly shorter in i-NE group (7.5 min [5.5-22.0 min] vs 49.3 min [29.5-60.0 min]; p < 0.001). Regional mesenteric and microcirculatory flows at jejunal mucosa and serosa were significantly higher in i-NE group at 4 and 6 hours after initiation of therapy ( p = 0.011, p = 0.032, and p = 0.017, respectively). Misdistribution of intestinal microcirculatory blood flow at the onset of shock was significantly reversed in i-NE group ( p < 0.001), which agreed with dynamic changes in mesenteric-lactate levels ( p = 0.01) and venous-to-arterial carbon dioxide differences ( p = 0.001). Animals allocated to i-NE showed significantly higher global end-diastolic volumes ( p = 0.015) and required significantly less resuscitation fluids ( p < 0.001) and lower doses of norepinephrine ( p = 0.001) at the end of the experiment. Pulmonary vascular permeability and extravascular lung water indexes were significantly lower in i-NE group ( p = 0.021 and p = 0.004, respectively). CONCLUSIONS: In endotoxemic shock, immediate start of norepinephrine significantly improved regional splanchnic and intestinal microcirculatory flows when compared with mandatory fixed-dose fluid loading preceding norepinephrine. Immediate norepinephrine strategy was related with less resuscitation fluids and lower vasopressor doses at the end of the experiment.

Effects of very early start of norepinephrine in patients with septic shock: a propensity score-based analysis.

BACKGROUND: Optimal timing for the start of vasopressors (VP) in septic shock has not been widely studied since it is assumed that fluids must be administered in advance. We sought to evaluate whether a very early start of VP, even without completing the initial fluid loading, might impact clinical outcomes in septic shock. METHODS: A total of 337 patients with sepsis requiring VP support for at least 6 h were initially selected from a prospectively collected database in a 90-bed mixed-ICU during a 24-month period. They were classified into very-early (VE-VPs) or delayed vasopressor start (D-VPs) categories according to whether norepinephrine was initiated or not within/before the next hour of the first resuscitative fluid load. Then, VE-VPs (n = 93) patients were 1:1 propensity matched to D-VPs (n = 93) based on age; source of admission (emergency room, general wards, intensive care unit); chronic and acute comorbidities; and lactate, heart rate, systolic, and diastolic pressure at vasopressor start. A risk-adjusted Cox proportional hazard model was fitted to assess the association between VE-VPs and day 28 mortality. Finally, a sensitivity analysis was performed also including those patients requiring VP support for less than 6 h. RESULTS: Patients subjected to VE-VPs received significantly less resuscitation fluids at vasopressor starting (0[0-510] vs. 1500[650-2300] mL, p < 0.001) and during the first 8 h of resuscitation (1100[500-1900] vs. 2600[1600-3800] mL, p < 0.001), with no significant increase in acute renal failure and/or renal replacement therapy requirements. VE-VPs was related with significant lower net fluid balances 8 and 24 h after VPs. VE-VPs was also associated with a significant reduction in the risk of death compared to D-VPs (HR 0.31, CI95% 0.17-0.57, p < 0.001) at day 28. Such association was maintained after including patients receiving vasopressors for < 6 h. CONCLUSION: A very early start of vasopressor support seems to be safe, might limit the amount of fluids to resuscitate septic shock, and could lead to better clinical outcomes.

Bench Validation of a Handcrafted Prototype Catheter for Intra-gastric Pressure Monitoring.

BACKGROUND: Abdominal compartment syndrome is a sustained intra-abdominal pressure (IAP) >20 mm Hg associated with new organ dysfunction. In order to prevent its development and related complications, IAP monitoring should be performed in patients with risk factors. Although techniques for its monitoring have been developed, they are of high cost and not always available in low- and lower-middle-income countries. Therefore, we aim to develop and validate in a bench model a handcrafted catheter to be used as an alternative method to measure the intra-gastric pressure (IGP) as a surrogate of the IAP. METHODS: We used an acrylic water container as a model of the abdomen and four handcrafted catheters made of a 16 Fr Levin tube with a globe finger tied with silk in the distal end, inflated with 1 cm of air. They were placed on the bottom of the container where the water pressure was directly measured as a gold standard. The agreement between the two measures was assessed with the Bland-Altman method. RESULTS: We performed 120 simultaneous measures. The mean pressure difference was 0.218 (95% CI 0.074 to 0.363). CONCLUSIONS: The handcrafted prototype catheter and the direct measure were highly correlated. The new catheter is a reliable and reproducible tool for pressure monitoring. However, before it can be used in the clinical setting for IAP monitoring, validation in human models in a real clinical setting needs to be performed.

Prolonged hourly neurological examinations are associated with increased delirium and no discernible benefit in mild/moderate geriatric traumatic brain injury.

BACKGROUND: Serial neurological examinations (NEs) are routinely recommended in the intensive care unit (ICU) within the first 24 hours following a traumatic brain injury (TBI). There are currently no widely accepted guidelines for the frequency of NEs. Disruptions to the sleep-wake cycles increase the delirium rate. We aimed to evaluate whether there is a correlation between prolonged hourly (Q1)-NE and development of delirium and to determine if this practice reduces the likelihood of missing the detection of a process requiring emergent intervention. METHODS: A retrospective analysis of patients with mild/moderate TBI, admitted to the ICU with serial NEs, was performed. Cohorts were stratified by the duration of exposure to Q1-NE, into prolonged (≥24 hours) and nonprolonged (<24 hours). Our primary outcomes of interest were delirium, evaluated using the Confusion Assessment Method; radiological progression from baseline images; neurological deterioration (focal neurological deficit, abnormal pupillary examination, or Glasgow Coma Scale score decrease >2); and neurosurgical procedures. RESULTS: A total of 522 patients were included. No significant differences were found in demographics. Patients in the prolonged Q1-NE group (26.1%) had higher Injury Severity Score with similar head Abbreviated Injury Score, significantly higher delirium rate (59% vs. 35%, p < 0.001), and a longer hospital/ICU length of stay when compared with the nonprolonged Q1-NE group. No neurosurgical interventions were found to be performed emergently as a result of findings on NEs. Multivariate analysis demonstrated that prolonged Q1-NE was the only independent risk factor associated with a 2.5-fold increase in delirium rate. The number needed to harm for prolonged Q1-NE was 4. CONCLUSION: Geriatric patients with mild/moderate TBI exposed to Q1-NE for periods longer than 24 hours had nearly a threefold increase in ICU delirium rate. One of five patients exposed to prolonged Q1-NE is harmed by the development of delirium. No patients were found to directly benefit as a result of more frequent NEs. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Trauma patients have reduced ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model of vessel injury.

Trauma is the leading cause of death in individuals up to 45 years of age. Alterations in platelet function are a critical component of trauma-induced coagulopathy (TIC), yet these changes and the potential resulting dysfunction is incompletely understood. The lack of clinical assays available to explore platelet function in this patient population has hindered detailed understanding of the role of platelets in TIC. The objective of this study was to assess trauma patient ex vivo flow-dependent platelet hemostatic capacity in a microfluidic model. We hypothesized that trauma patients would have flow-regime dependent alterations in platelet function. Blood was collected from trauma patients with level I activations (N = 34) within 60 min of hospital arrival, as well as healthy volunteer controls (N = 10). Samples were perfused through a microfluidic model of injury at venous and arterial shear rates, and a subset of experiments were performed after incubation with fluorescent anti-CD41 to quantify platelets. Complete blood counts were performed as well as plasma-based assays to quantify coagulation times, fibrinogen, and von Willebrand factor (VWF). Exploratory correlation analyses were employed to identify relationships with microfluidic hemostatic parameters. Trauma patients had increased microfluidic bleeding times compared to healthy controls. While trauma patient samples were able to deposit a substantial amount of clot in the model injury site, the platelet contribution to microfluidic hemostasis was attenuated. Trauma patients had largely normal hematology and plasma-based coagulation times, yet had elevated D-Dimer and VWF. Venous microfluidic bleeding time negatively correlated with VWF, D-Dimer, and mean platelet volume (MPV), while arterial microfluidic bleeding time positively correlated with oxygenation. Arterial clot growth rate negatively correlated with red cell count, and positively with mean corpuscular volume (MCV). We observed changes in clot composition in trauma patient samples reflected by significantly diminished platelet contribution, which resulted in reduced hemostatic function in a microfluidic model of vessel injury. We observed a reduction in platelet clot contribution under both venous and arterial flow ex vivo in trauma patient samples. While our population was heterogenous and had relatively mild injury severity, microfluidic hemostatic parameters correlated with different patient-specific data depending on the flow setting, indicating potentially differential mechanistic pathways contributing to platelet hemostatic capacity in the context of TIC. These data were generated with the goal of identifying key features of platelet dysfunction in bleeding trauma patients under conditions of flow and to determine if these features correlate with clinically available metrics, thus providing preliminary surrogate markers of physiological platelet dysfunction to be further studied across larger cohorts. Future studies will continue to explore those relationships and further define mechanisms of TIC and their relationship with patient outcomes.

Open Mandible and Maxillary Fractures Associated with Higher Risk of Infection in Victims of Assault.

Background: Victims of assault (VOA) often present with fractures of the mandible and maxilla. They represent a complex challenge because of possible compromise of the airway, and infection-related complications because of potential involvement of the oral cavity. We hypothesized that open mandible and maxillary fractures in VOA are associated with a higher rate of infection compared with non-VOA patients with open facial fractures. Patients and Methods: Patients admitted to our level 1 trauma center from 2005 to 2020 with a diagnosis of open mandible and maxillary fractures were included. Demographics, mechanisms of injury, fracture location, cultures, infectious complications, antibiotic treatments, and clinical outcomes were abstracted. Patients were stratified by their mechanism of injury into VOA or non-VOA and were compared using χ2 and Student t-test using SPSS (IBM Corp, Armonk, NY). Results: We identified 316 patients with open mandible and maxillary fractures. There were 198 patients categorized as being VOA, and 118 as non-VOA. Nineteen of 316 patients were diagnosed with infection related to the fracture (3.8% abscesses, 1.9% cellulitis, and 1.9% osteomyelitis). Although the Injury Severity Score (ISS) was higher in non-VOA patients (5.8 ± 2.6 vs. 4.9 ± 1.8; p < 0.013), most of the infections were in the VOA cohort (17/19; 89.5%; p < 0.013). Conclusions: Open fractures of the mandible and maxilla in VOA are associated with a greater risk of infection compared with non-victims of assault. The relation between VOA and poor SDH has been studied recently; clinicians should be aware of this association and implement special considerations and appropriate follow-up visits to decrease the rate of infection in this currently expanding population.

Outcomes in Patients With COVID-19 With Acute Encephalopathy and Coma: An International Prospective Study.

BACKGROUND AND OBJECTIVES: To report the prevalence of acute encephalopathy and outcomes in patients with severe coronavirus disease 2019 (COVID-19) and to identify determinants of 90-day outcomes. METHODS: Data from adults with severe COVID-19 and acute encephalopathy were prospectively collected for patients requiring intensive care unit management in 31 university or university-affiliated intensive care units in 6 countries (France, United States, Colombia, Spain, Mexico, and Brazil) between March and September of 2020. Acute encephalopathy was defined, as recently recommended, as subsyndromal delirium or delirium or as a comatose state in case of severely decreased level of consciousness. Logistic multivariable regression was performed to identify factors associated with 90-day outcomes. A Glasgow Outcome Scale-Extended (GOS-E) score of 1-4 was considered a poor outcome (indicating death, vegetative state, or severe disability). RESULTS: Of 4,060 patients admitted with COVID-19, 374 (9.2%) experienced acute encephalopathy at or before the intensive care unit (ICU) admission. A total of 199/345 (57.7%) patients had a poor outcome at 90-day follow-up as evaluated by the GOS-E (29 patients were lost to follow-up). On multivariable analysis, age older than 70 years (odds ratio [OR] 4.01, 95% CI 2.25-7.15), presumed fatal comorbidity (OR 3.98, 95% CI 1.68-9.44), Glasgow coma scale score <9 before/at ICU admission (OR 2.20, 95% CI 1.22-3.98), vasopressor/inotrope support during ICU stay (OR 3.91, 95% CI 1.97-7.76), renal replacement therapy during ICU stay (OR 2.31, 95% CI 1.21-4.50), and CNS ischemic or hemorrhagic complications as acute encephalopathy etiology (OR 3.22, 95% CI 1.41-7.82) were independently associated with higher odds of poor 90-day outcome. Status epilepticus, posterior reversible encephalopathy syndrome, and reversible cerebral vasoconstriction syndrome were associated with lower odds of poor 90-day outcome (OR 0.15, 95% CI 0.03-0.83). DISCUSSION: In this observational study, we found a low prevalence of acute encephalopathy at ICU admission in patients with COVID-19. More than half of patients with COVID-19 presenting with acute encephalopathy had poor outcomes as evaluated by GOS-E. Determinants of poor 90-day outcome were dominated by older age, comorbidities, degree of impairment of consciousness before/at ICU admission, association with other organ failures, and acute encephalopathy etiology. TRIAL REGISTRATION INFORMATION: The study is registered with ClinicalTrials.gov, number NCT04320472.

Acute Acalculous Cholecystitis-Associated Bacteremia Has Worse Outcome.

Background: Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder without gallstones in the setting of critical illness. It represents 2%-15% of acute cholecystitis (AC) cases. Bacteremia is associated with increased morbidity and mortality rates in patients in the intensive care unit (ICU). The incidence of bacteremia in acute calculous cholecystitis (ACC) has been described; however, the incidence of bacteremia in AAC has not been reported. We hypothesized that patients with AAC have higher bacteremia rates, leading to worse outcomes than in those with ACC. Methods: A prospectively collected acute care surgery (ACS) institutional database of patients treated from 2008 through 2018 was queried for patients having ACC using International Classification of Diseases (ICD) 9 and 10 codes. Demographics, microbiology findings, and outcomes were extracted. Only patients with positive blood cultures were included in the study. We defined two cohorts: AAC with bacteremia and ACC with bacteremia. The Student t-test was used for continuous variables and the χ2 and Fisher exact tests for categorical variables. Multivariable regression was applied, and statistical significance was set at p < 0.05. Results: Of 323 patients with AC, 57 (17.6%) had AAC and 266 (82.4%) had ACC. Of the 19 patients who had a blood culture, 11 (57.8%) were positive. Patients with positive blood cultures had a mean age of 56.7 ± 15.3 years and a mean Body Mass Index (BMI) of 26.7 ± 4.9. The incidence of bacteremia was significantly higher in AAC (n = 6; 10.5% versus n = 5; 1.9 %; p = 0.005), although the time between admission and diagnosis of bacteremia was similar in the two groups (1.2 ± 1.1 versus 0.2 ± 0.5 days; p = 0.128). The patients with AAC and bacteremia were younger (53.8 ± 19.2 versus 60.2 ± 8 years; p = 0.021) and had a longer ICU length of stay (LOS) (12.6 ± 7.2 versus 1.3 ± 2.1 days; p = 0.030). However, there was no difference in the mortality rate in the groups (n = 2; 33.3% versus 1; 20.0%; p = 1.000). After adjusting for age, gender, BMI, and Charlson Comorbidity Index, bacteremia in AAC patients was found to be an independent variable for longer ICU LOS (odds ratio 8.8; 95% confidence interval 1.7-15.9; p = 0.024). Conclusions: The incidence of bacteremia in patients with AAC is five-fold higher and the ICU stay eight days longer than in patients with ACC.

Temporary Abdominal Closure Is Associated with Increased Risk for Fungal Intra-Abdominal Infections in Trauma Patients.

Background: Fungal infections are associated with increased morbidity and death. Few studies have examined risk factors associated with post-operative fungal intra-abdominal infections (FIAIs) in trauma patients after exploratory laparotomy. In this study, we evaluated potential risk factors for acquiring post-operative FIAIs and their impact on clinical outcomes. Methods: This was a retrospective analysis of trauma patients admitted from 2005 to 2018 who underwent exploratory laparotomy and subsequently had development of intra-abdominal infection (IAI). Demographics, comorbidities, culture data, antimicrobial usage, Injury Severity Scores (ISS), and clinical outcomes were abstracted. All post-operative IAIs were evaluated and stratified as either bacterial, fungal, combined, and with or without colonization. All groups were compared. Risk factors for the development of post-operative IAI and clinical outcomes were analyzed by Student t test and chi-square test. Multi-variable logistic regression was used to determine independent predictors of post-operative FIAIs. Results: There were 1675 patients identified as having undergone exploratory laparotomy in the setting of traumatic injury, 161 of whom were suspected of having IAI. A total of 105 (6.2%) patients had a diagnosis of IAI. Of these patients, 40 (38%) received a diagnosis of FIAI. The most common fungal pathogens were unspeciated yeast (48.3%), followed by Candida albicans (42.7%), C. glabrata (4.5%), C. dubliniensis (2.25%), and C. tropicalis (2.25%). There were no significant differences in demographics, comorbidities, and percentage of gastric perforations between FIAI and bacterial IAI (BIAI) groups. Patients with FIAIs, however, had a 75% temporary abdominal closure (TAC) rate compared with 51% in BIAIs (p = 0.01). The FIAI group had higher ISS (27 vs. 22, p = 0.03), longer hospital days (34 vs. 25, p = 0.02), and longer intensive care unit (ICU) days (17 vs. 9, p = 0.006) when compared with BIAI. The FIAI group also had a five-fold greater mortality rate. Logistic regression identified TAC as an independent risk factor for the development of post-operative FIAIs (odds ratio [OR] 6.16, confidence interval [CI] 1.14-28.0, p = 0.02). Conclusions: An FIAI after exploratory laparotomy was associated with greater morbidity and death. A TAC was associated independently with increased risk of FIAI after exploratory laparotomy in the setting of traumatic injury. Clinicians should suspect fungal infections in trauma patients in whom post-operative IAI develops after undergoing exploratory laparotomy using TAC techniques.

Diastolic shock index and clinical outcomes in patients with septic shock.

BACKGROUND: Loss of vascular tone is a key pathophysiological feature of septic shock. Combination of gradual diastolic hypotension and tachycardia could reflect more serious vasodilatory conditions. We sought to evaluate the relationships between heart rate (HR) to diastolic arterial pressure (DAP) ratios and clinical outcomes during early phases of septic shock. METHODS: Diastolic shock index (DSI) was defined as the ratio between HR and DAP. DSI calculated just before starting vasopressors (Pre-VPs/DSI) in a preliminary cohort of 337 patients with septic shock (January 2015 to February 2017) and at vasopressor start (VPs/DSI) in 424 patients with septic shock included in a recent randomized controlled trial (ANDROMEDA-SHOCK; March 2017 to April 2018) was partitioned into five quantiles to estimate the relative risks (RR) of death with respect to the mean risk of each population (assumed to be 1). Matched HR and DAP subsamples were created to evaluate the effect of the individual components of the DSI on RRs. In addition, time-course of DSI and interaction between DSI and vasopressor dose (DSI*NE.dose) were compared between survivors and non-survivors from both populations, while ROC curves were used to identify variables predicting mortality. Finally, as exploratory observation, effect of early start of vasopressors was evaluated at each Pre-VPs/DSI quintile from the preliminary cohort. RESULTS: Risk of death progressively increased at gradual increments of Pre-VPs/DSI or VPs/DSI (One-way ANOVA, p < 0.001). Progressive DAP decrease or HR increase was associated with higher mortality risks only when DSI concomitantly increased. Areas under the ROC curve for Pre-VPs/DSI, SOFA and initial lactate were similar, while mean arterial pressure and systolic shock index showed poor performances to predict mortality. Time-course of DSI and DSI*NE.dose was significantly higher in non-survivors from both populations (repeated-measures ANOVA, p < 0.001). Very early start of vasopressors exhibited an apparent benefit at higher Pre-VPs/DSI quintile. CONCLUSIONS: DSI at pre-vasopressor and vasopressor start points might represent a very early identifier of patients at high risk of death. Isolated DAP or HR values do not clearly identify such risk. Usefulness of DSI to trigger or to direct therapeutic interventions in early resuscitation of septic shock need to be addressed in future studies.

Integrated process for the recovery of yttrium and europium from CRT phosphor waste.

An integrated process flow sheet for the recovery of yttrium and europium from waste cathode-ray tube (CRT) phosphors was developed. This flow sheet is based on a sequence of roasting, leaching with organic acids and precipitation steps. Zinc was efficiently removed from the roasted CRT phosphors by leaching with acetic acid, giving access to the rare earth content. Yttrium and europium were quantitatively leached from the residue by a 1 mol L-1 methanesulphonic acid (MSA) solution. Precipitation with oxalic acid gave a mixed Y/Eu oxalate of high purity (>99 wt%). Co-precipitation of zinc was less than 2 wt%.

Early Emergency General Surgery Is Associated with a Higher Incidence of Clostridium difficile Infection.

BACKGROUND: Clostridium difficile infection (CDI) is an important surgical complication. Emergency general surgery (EGS) is a developing area of the acute care surgical practice. Few studies evaluating the incidence and risk factors of CDI in this patient population are available. PATIENTS AND METHODS: A prospectively maintained Acute and Critical Care Surgery registry spanning from 2008 to 2015 was queried for cases of operative EGS with clinical suspicion of CDI post-operatively. Diagnosis of CDI was made using toxin A/B assay in stools. Demographics, co-morbidities, surgical procedures, length of stay (LOS), intensive care unit LOS, antibiotic use, and death were obtained. The patients positive and negative for CDI were compared using chi-squared and Student's t-test. Multi-variable logistic regression was used to determine risk factors for CDI. RESULTS: A total of 550 patients were identified. The total incidence of CDI was 12.7%. There was no significant difference in demographics between CDI positive and negative patients. Average time to CDI diagnosis was 10.1 ± 8.5 days post-operatively. Patients who received three or more antibiotic classes were at higher risk of CDI developing post-operatively (83% vs. 75%, p = 0.04). The CDI positive patients underwent an EGS significantly earlier than CDI negative patients (0.9 ± 2.3 vs. 3.2 ± 9.2 days, p < 0.001). The most common procedures were partial colectomies (21.4%); small bowel resections/repairs (12.9%); gastric repair for perforated peptic ulcer (10%); skin and soft tissue procedure (7.1%), and laparotomies (5.7%). There was no difference in outcomes between the groups. On linear regression, an EGS performed later after admission was an independent risk factor for lower CDI (OR 0.87; CI 95% [0.79-0.96], p < 0.01). CONCLUSION: Patients undergoing an early EGS have a high incidence of CDI. The number of antibiotic classes administered post-operatively affects CDI status. Bowel resections appear to be at increased risk for CDI. Clinicians should have a high index of suspicion and low threshold for testing C. difficile in high-risk EGS patients.

Pre-Operative Anti-Fungal Therapy Does Not Improve Outcomes in Perforated Peptic Ulcers.

BACKGROUND: With the advent of anti-Helicobacter pylori therapy, hospital admissions for peptic ulcer disease (PUD) have declined significantly since the 1990s. Despite this, operative treatment of PUD still is common. Although previous papers suggest that Candida in peritoneal fluid cultures may be associated with worse outcomes in patients with perforated peptic ulcers (PPUs), post-operative anti-fungal therapy has not been effective. We hypothesized that pre-operative anti-fungal drugs improve outcomes in patients with PPUs undergoing operative management. PATIENTS AND METHODS: A prospectively maintained Acute and Critical Care Surgery (ACCS) database spanning 2008-2015 and including more than 7,000 patients was queried for patients with PPUs. Demographics and clinical outcomes were abstracted. Pre-operative anti-fungal use, intra-operative peritoneal fluid cultures, and infectious outcomes were abstracted manually. We compared outcomes and the presence of fungal infections in patients receiving peri-operative anti-fungal drugs in the entire cohort and in patients with intra-operative peritoneal fluid cultures. Frequencies were compared by the Fisher exact or χ2 test as appropriate. The Student's t-test was used for continuous variables. RESULTS: There were 107 patients with PPUs who received operative management; 27 (25.2%) received pre-operative anti-fungal therapy; 33 (30.8%) received peritoneal fluid culture, and 17 cultures (51.5%) were positive for fungus. The presence of fungus in the cultures did not affect the outcomes. There were no differences in length of stay (LOS), intensive care unit (ICU) LOS, ventilator days, 30-day re-admission rates, or rates of intra-abdominal abscess formation or fungemia in patients who received pre-operative anti-fungal drugs regardless of the presence of fungi in the peritoneal fluid. CONCLUSION: Candida has been recovered in 29%-57% of peritoneal fluid cultures in patients with PPUs. However, no studies have evaluated pre-operative anti-fungal therapy in PPUs. Our data suggest that pre-operative anti-fungal drugs are unnecessary in patients undergoing operative management for PPU.

Aspectos reproductivos de la raya látigo Hypanus longus (Garman, 1880) de los desembarques de la pesca artesanal en el Pacífico de Guatemala / Reproductive aspects of the longtail stingray Hypanus longus (Garman, 1880) from the landings of the artisanal fishery in the Pacific of Guatemala

La raya látigo Hypanus longus, ha pasado de ser una especie de captura incidental a una especie objetivo en la pesca artesanal del Pacífico de Guatemala. Esta actividad es realizada sin considerar criterios biológicos esenciales para su aprovechamiento sostenible. Aunado a ello, H. longus es una especie sensible, presentando características biológicas como: madurez sexual tardía, ciclos reproductivos largos y baja fecundidad. El presente estudio contribuye al conocimiento de la biología reproductiva de la raya látigo. Durante mayo de 2019 a marzo de 2020 se realizaron 11 muestreos de los desembarques de la pesca artesanal en la comunidad de Sipacate, Escuintla, en cada muestreo se registró el ancho de disco (AD), el peso, sexo y estado de maduración sexual de H. longus. En total se registraron 336 organismos, que presentaron una proporción sexual de 1:1, un AD para hembras de M = 82.33 cm, DS = 22.24 y de M = 76.91 cm, DS = 11.86 para machos. A partir de las evaluaciones externas e internas de los aparatos reproductores se determinó la talla de madurez sexual (L50), siendo de 88.2 y 79.3 cm AD para hembras y machos respectivamente. Finalmente, este estudio evidencio que el 65.68% de hembras y el 52.10% de machos son capturados por debajo de la L50, por lo cual se recomienda elaborar e implementar estra-tegias o medidas tendientes a la regulación de las prácticas pesqueras o artes de pesca que permitan la captura de organismos mayores a 95 cm de AD.

The whip ray Hypanus longushas gone from being a bycatch species to a target species in artisanal fisheries in the Pacific of Guatemala. This activity is carried out without considering essential biological criteria for its sustainable use. In addition, H. longusis a sensitive species, presenting biological characteristics such as late sexual maturity, long reproductive cycles and low fecundity. The present study contributes to the knowledge of the reproductive biology of the whip ray. During May 2019 to March 2020, 11 samplings were conducted from artisanal fishery landings in the community of Sipacate, Escuintla, in each sampling the disc width (AD), weight, sex and sexual maturation stage of H. longus were recorded. A total of 336 organisms were recorded, which pre-sented a sex ratio of 1:1, with a female AD of M = 82.33 cm, SD = 22.24 and M = 76.91 cm, SD = 11.86 for males. From the external and internal evaluations of the reproductive apparatus, the size at sexual maturity (L50) was determined to be 88.2 and 79.3 cm AD for females and males, respectively. Finally, this study showed that 65.68% of females and 52.10% of males are caught below L50, so it is recommended to develop and implement strategies or measures to regulate fishing practices or fishing gear that allow the capture of organisms larger than 95 cm AD.

Diversidad malacológica del humedal marino-costero Las Lisas-La Barrona en el Pacífico de Guatemala / Malacological diversity of the Las Lisas-La Barrona marine coastal wetland in the Pacific of Guatemala

Los moluscos son uno de los grupos faunísticos dominantes en ambientes estuarinos con bosque de manglar como el humedal Las Lisas-La Barrona. Forman parte de la transferencia de energía a través de las redes tróficas y contribuyen a la estructuración de los hábitats bénticos. El humedal Las Lisas-La Barrona se ubica en el litoral Pacífico de Guatemala. Se determinó la diversidad de la comunidad de moluscos, así como su relación con los parámetros fisicoquímicos del agua. Se realizaron ocho muestreos (enero a agosto) en 2017, utilizando parcelas con un área de 16 m2 en seis sitios de bosque de manglar y cuatro sitios en el canal estuarino, distribuidos en el humedal. La riqueza de moluscos del humedal está comprendida por 26 especies correspondientes a 18 familias y 22 géneros. Las especies más abundantes de gasterópodos fueron Cerithideopsis californica (Adams, 1852) y Littoraria fasciata (Gray, 1839) y de bivalvos Iliochione subrugosa (Wood, 1828) y Larkinia grandis (Broderip & Sowerby, 1829). Los sitios correspondientes a bosque de manglar presentaron una mayor cantidad de moluscos, principalmente gasterópodos. La distribución de las especies dominantes, no está dada por los factores fisicoquímicos del agua, pudiendo ser otros factores como la disponibilidad de hábitat y alimento los que rijan su distribución dentro del humedal. Algunos factores como la influencia de agua marina dentro del humedal, las altas concentraciones de oxígeno disuelto y pH ligeramente básicos, así como la calidad del agua en general, hacen del humedal Las Lisas-La Barrona un área muy diversa en cuanto a especies de moluscos.

Molluscs are one of the dominant faunistic groups in estuarine environments with mangrove forests such as the Las Lisas-La Barrona wetland. They are part of the transfer of energy through trophic networks and contribute to the structuring of the benthic habitats. The Las Lisas-La Barrona wetland is located on the Pacific coast of Guatemala. The diversity of the mollusk community, as well as its relationship with the physicochemical parameters of the water was determined. Eight samplings were carried out (January to August) in 2017, using parcels with an area of 16 m2 in six mangrove forest sites and four sites in the estuarine channel, distributed along the wetland. The mollusk richness of the wetland is comprised of 26 species corresponding to 18 families and 22 genera. The most abundant species of gastropods were Cerithideopsis californica (Adams, 1852) and Littoraria fasciata (Gray, 1839) and bivalves Iliochione subrugosa (Wood, 1828) and Larkinia grandis (Broderip & Sowerby, 1829). The sites corresponding to mangrove forest, presented a greater amount of mollusks, mainly gastropods. The distribution of dominant species is not given by the physicochemical factors of the water, being able to be other factors such as the availability of habitat and food that govern their distribution within the wetland. Some factors such as the influence of seawater in the wetland, the high concentrations of dissolved oxygen and the slightly basic levels of pH, as well as water quality in general, make the Las Lisas-La Barrona wetland a very diverse area in terms of mollusk species

Efecto del microhábitat sobre la abundancia y riqueza específica de los macroinvertebrados bentónicos en dos ríos tropicales de montaña, Guatemala / Effect of microhabitat on the abundance and specific richness of benthic macroinvertebrates in two tropical mountain streams, Guatemala

Los macroinvertebrados bentónicos cumplen funciones ecológicas importantes en los sistemas lóticos, como el traspaso de energía a través de las redes tróficas, la descomposición de la materia orgánica, el reciclaje de nutrientes y la mezcla de sedimentos. Uno de los principales factores que definen la composición del ensamble de macroinvertebrados es la disponibilidad de microhábitats. Debido a ello, se evaluó el efecto de ocho microhábitats (hojarasca, grava, piedras, roca, musgo, vegetación acuática, pozas y cataratas), así como de la velocidad y profundidad, sobre la abundancia y riqueza específica de los macroinvertebrados en los ríos La Labor y Tzununá en la cuenca del lago Atitlán en el altiplano de Guatemala. Se colectaron 19,529 organismos correspondientes a 91 taxa, 49 familias y 65 géneros. El microhábitat que presentó mayor abundancia fue hojarasca (7,723 organismos) y pozas presentó la menor (652 organismos). En cuanto a riqueza, piedras presentó la mayor riqueza (41 taxa) y musgo tuvo la menor (28 taxa). Se evidenció que el microhábitat tuvo un efecto significativo sobre la abundancia y la riqueza (p < .05), ésta última también se vio influenciada por la profundidad (p = .030). Se concluyó que el microhábitat es un factor importante, para determinar la composición de la comunidad de macroinvertebrados; ya que la presencia y dominancia de elementos de heterogeneidad en los ríos, contribuye a incrementar la diversidad del hábitat físico, así como las opciones de alimento y refugio, promoviendo la abundancia y riqueza de macroinvertebrados en los sistemas lóticos.

Benthic macroinvertebrates serve important ecological functions in lotic systems, such as the transfer of energy through trophic networks, decomposition of organic matter, nutrient recycling and sediment mixing. One of the main factors that define the composition of the macroinvertebrate assemblage is the availability of microhabitats. The survey evaluated the effect of eight microhabitats (leaf litter, gravel, stones or pebbles, rock, moss, aquatic vegetation, pools and waterfalls), as well as speed and depth, on the abundance and specific richness due to rarefaction of the macroinvertebrates in La Labor and Tzununá rivers, which are part of the Lake Atitlán basin in the Guatemalan highlands. In this area 19,529 organisms corresponding to 91 taxa, 49 families and 65 genera were collected. The highest abundance was in leaf litter microhabitat (7,723 organisms), while stones showed the highest richness (41 taxa). Pools had the lowest abundance (652 organisms) and moss had the lowest richness (28 taxa). The microhabitat has a significant effect on abundance and richness (p < .05), also depth has a significant effect on richness (p = .030). The microhabitat is an important factor, to determine the composition of the macroinvertebrate community, because the presence and dominance of elements of heterogeneity in the rivers contributes to increase the diversity of the physical habitat, which provides refuge and food that satisfy the requirements of organisms promoting the abundance and richness of macroinvertebrates in lotic systems.

Radiative and Non-Radiative Lifetime Engineering of Quantum Dots in Multiple Solvents by Surface Atom Stoichiometry and Ligands.

CdTe quantum dots have unique characteristics that are promising for applications in photoluminescence, photovoltaics or optoelectronics. However, wide variations of the reported quantum yields exist and the influence of ligand-surface interactions that are expected to control the excited state relaxation processes remains unknown. It is important to thoroughly understand the fundamental principles underlying these relaxation processes to tailor the QDs properties to their application. Here, we systematically investigate the roles of the surface atoms, ligand functional groups and solvent on the radiative and non-radiative relaxation rates. Combining a systematic synthetic approach with X-ray photoelectron, quantitative FT-IR and time-resolved visible spectroscopies, we find that CdTe QDs can be engineered with average radiative lifetimes ranging from nanoseconds up to microseconds. The non-radiative lifetimes are anticorrelated to the radiative lifetimes, although they show much less variation. The density, nature and orientation of the ligand functional groups and the dielectric constant of the solvent play major roles in determining charge carrier trapping and excitonic relaxation pathways. These results are used to propose a coupled dependence between hole-trapping on Te atoms and strong ligand coupling, primarily via Cd atoms, that can be used to engineer both the radiative and non-radiative lifetimes.

Estado poblacional del pepino de mar (Clase Holothuroidea) en el Caribe de Guatemala / Population status of Sea Cucumber (Class Holothuroidea) in the Caribbean of Guatemala

Los holoturoideos o pepinos de mar pertenecen al filo Echinodermata, e incluyen animales con cuerpo vermiforme alargado y blando que viven en los fondos de los mares de todo el mundo. Ecológicamente estos organismos son recicladores eficientes de sedimentos en el ambiente. En los últimos años han cobrado alto valor comercial en el mercado asiático, por lo que su pesquería se ha expandido hacia muchos países. En Guatemala se decretó una veda precautoria en el 2010 por cinco años, al terminar esta se extendió por dos años más, pero con el compromise de obtener información científica durante dicho período. Con este fin, se realizó una evaluación poblacional del pepino de mar a través de transectos lineales de 60 m2, en siete puntos de la bahía de Amatique y la zona expuesta del mar Caribe de Guatemala, durante abril, junio y septiembre del 2016. Se evaluaron 6,300 m2, encontrando un total de 64 individuos de pepinos de mar. La riqueza de holotúridos está representada por siete especies, siendo las más abundantes Isostichopus badionotus (Selenka, 1867) y Holothuria mexicana (Ludwig, 1875). Los sitios con mayor abundancia fueron Faro Rojo y King Fish (p = .004). En base a los resultados de esta evaluación se puede determinar que la explotación comercial de los pepinos de mar en el Caribe guatemalteco no es viable, y que para aprovechar el valor comercial de estas especies se podría impulsar la acuicultura y comercializarlo a través de un sistema eficiente de trazabilidad.

Holothurians or sea cucumbers belong to the filum Equinodermata, which includes animals with long soft vermiform bodies that live on the ocean bottom of the entire world. Ecologically these organisms are efficient recyclers of sediments in the environment. In recent years, they have gained high commercial value in the Asian market, so their fishery has expanded to many countries. In Guatemala, a precautionary ban was decreed in 2010 for five years, when it ended it was extended for two more years, but with the commitment to obtain scientific information during that period. For this purpose, a population assessment of sea cucumber was carried out through linear transects of 60 m2, in seven points of Amatique Bay and the exposed zone of the Caribbean Sea of Guatemala, during April, June and September of 2016. 6300 m2 were evaluated, founding 64 organisms. The holothurians richness is represented by seven species, being the most abundant Isostichopus badionotus (Selenka, 1867) and Holothuria mexicana (Ludwig, 1875). The most abundant sites were Faro Rojo and King Fish (p = .004). Based on the results of this evaluation, it can be determined that the commercial exploitation of sea cucumbers in the guatemalan Caribbean is not viable, and that to take advantage of the commercial value of these species, aquaculture could be promoted and marketed through an efficient traceability system.

Riqueza y abundancia de peces arrecifales en el Caribe de Guatemala utilizando Estaciones Remotas de Video Subacuático con Carnada / Richness and abundance of reef fish in the Caribbean of Guatemala using Baited Remote Underwater Video Stations

El mar Caribe de Guatemala forma parte del Sistema Arrecifal Mesoamericano (SAM), el cual alberga una alta diversidad de especies marinas. Dichas poblaciones son importantes para el bienestar de las comunidades humanas que habitan en la zona marino-costera de los países que conforman el SAM, y que dependen de manera directa o indirecta de estos recursos. El objetivo de este estudio fue determinar la riqueza y abundancia tanto de las especies de peces herbívoros presentes en el área, como de aquellas que son atraídas por carnada de sábalo y atún, utilizando la metodología de Estaciones Remotas de Video Subacuático con Carnada BRUVS en sitios con presencia de arrecifes. El muestreo se realizó en siete sitios ubicados fuera de la Bahía de Amatique, Izabal, en abril, junio y septiembre de 2016. Se grabaron 26.06 h, en 21 sets de BRUVS. Se contabilizaron 778 organismos, correspondientes a dos clases, 20 familias, 31 géneros y 59 especies. Las especies más abundantes en el estudio fueron Scarus spp. (19.67 %), Clepticus parrae (9.64 %), Aluterus scriptus (6.04 %), Scarus iserti (5.14 %) y Caranx ruber (5.01 %). Los sitios Quetzalito 1 y 2 presentaron una riqueza de especies significativamente mayor (p < 0.006) al resto de sitios de muestreo. Quetzalito 1, 2 y King Fish presentaron una abundancia significativamente mayor (p < .038) al resto de sitios. El dendrograma derivado de la abundancia por especie para los sitios de muestreo, mostró cinco agrupaciones (similaridad de Bray-Curtis del 43 %). Finalmente se observó una baja presencia de peces de importancia comercial en los siete puntos evaluados.

The Guatemalan Caribbean Sea forms part of the Mesoamerican Reef System (MAR), which harbors a great marine biodiversity. These populations are important for the wellness of humans who live in communities at coastal areas located in the MAR region, and who directly or indirectly depend on these resources to survive and thrive. The main objective of this study was to determine not only species richness and abundance of herbivorous fish, but also those who are attracted by shad and tuna bait when used in the Baited Remote Underwater Video Stations (BRUVS) in sites with coral reef presence. Monitoring was held at seven spots located outside Bahía de Amatique, Izabal, in April, June and September 2016. In 21 sets of BRUVS, 26.06 h of video were recorded, counting a total of 778 organisms which belongs to two classes, 20 families, 31 genera and 59 species. The most abundant species were Scarus spp. (19.67 %), Clepticus parrae (9.64 %), Aluterus scriptus (6.04 %), Scarus iserti (5.14 %) and Caranx ruber (5.01 %). The sites that presented higher richness of species were Quetzalito 1 y 2 (p < 0.006 compared to the rest of the sampled sites). Quetzalito 1, 2 and King Fish showed higher abundance (p < .038) compared to the rest of the sites. Abundance per specie dendrogram showed five groups (Bray-Curtis similarity of 43 %). Finally, low presence of commercial fish species was seen at the seven monitored sites.