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Objective To determine whether high-dose dexamethasone increases the number of ventilator-free days (VFD) among patients with acute respiratory distress syndrome (ARDS) caused by COVID-19. Design Multicenter, randomized, open-label, clinical trial. Participants Consecutive patients with confirmed COVID-19-related ARDS were enrolled from June 17, 2020, to March 27, 2021, in four intensive care units (ICUs) in Argentina Intervention 16 mg of dexamethasone intravenously daily for five days followed by 8 mg of dexamethasone daily for five days or 6 mg of dexamethasone intravenously daily for 10 days. Main Outcome and Measures The primary outcome was ventilator-free days during the first 28 days. The secondary outcomes were all-cause mortality at 28 and 90 days, infection rate, muscle weakness, and glycemic control in the first 28 days. Results Data from 98 patients who received at least one dose of dexamethasone were analyzed. The trial was prematurely terminated due to low enrollment rate. At 28 days after randomization, there was no difference between high- and low-dose dexamethasone groups in VFD (median, 0 [interquartile range [IQR] 0-14] vs. 0 [IQR 0-1] days; P = .231), or in the mean duration of mechanical ventilation (19 ± 18 vs. 25 ± 22 days; P = .078). The cumulative hazard of successful discontinuation from mechanical ventilation was increased by the high-dose treatment (adjusted sub-distribution hazard ratio: 1.84; 95% CI: 1.31 to 2.5; P Conclusions Among patients with ARDS due to COVID-19, the use of higher doses of dexamethasone compared with the recommended low-dose treatment did not show an increase in VFD. However, the higher dose significantly improved the time required to liberate them from the ventilator

The criteria for the selection of COVID-19 patients that could benefit most from ECMO organ support are yet to be defined. In this study, we evaluated the predictive performance of ECMO mortality predictive models in patients with COVID-19. We also performed a cost-benefit analysis depending on the mortality predicted probability. We conducted a retrospective cohort study in COVID-19 patients who received ECMO at two tertiary care hospitals between March 2020 to July 2021. We evaluated the discrimination (C-statistic), calibration (Cox calibration), and accuracy of the prediction of death due to severe ARDS in V-V ECMO score (PRESERVE), the Respiratory Extracorporeal Membrane Oxygenation Survival Score (RESP) score, and the PREdiction of Survival on ECMO Therapy-Score (PRESET) score. In addition, we compared the RESP score with Plateau pressure instead of Peak pressure. We included a total of 36 patients, 29 (80%) of them male and with a median (IQR) APACHE of 10 (8-15). The PRESET score had the highest discrimination (AUROCs 0.81 [95%CI 0.67 - 0.94]) and calibration (calibration-in-the-large 0.5 [95%CI -1.4 - 0.3]; calibration slope 2.2 [95%CI 0.7 / 3.7]). The RESP score with Plateau pressure had higher discrimination than the conventional RESP score. The cost per QALY in the USA, adjusted to life expectancy, was higher than USD 100,000 in patients older than 45 years with a PRESET10. The PRESET score had the highest predictive performance and could help in the selection of patients that benefit most from this resource-demanding and highly invasive organ support.

PurposeTo determine whether high-dose dexamethasone increases the number of ventilator-free days (VFD) among patients with acute respiratory distress syndrome due to coronavirus disease 2019 (C-ARDS)MaterialsA multicenter randomized controlled trial in adults with C-ARDS. Patients received 16 mg/d of dexamethasone intravenously for five days followed by 8 mg/d of dexamethasone for five days, or 6 mg/d of dexamethasone intravenously for 10 days.ResultsData from 98 patients who received at least one dose of dexamethasone were analyzed. At 28 days after randomization, there was no difference between high- and low-dose dexamethasone groups in VFD (median, 0 d [interquartile range (IQR) 0–14 d] versus 0 d [IQR 0–1 d]; P=0.231). The cumulative hazard of successful discontinuation from mechanical ventilation was increased by the high-dose treatment (adjusted sub-distribution hazard ratio: 1.84; 95% CI: 1.31 to 2.5; PConclusionsAmong patients with C-ARDS, the use of higher doses of dexamethasone compared with the recommended low-dose treatment did not show an increase in VFD. However, the higher dose significantly improved the time required to liberate them from the ventilatorClinical Trial Registered: NCT04395105

Objectives The aim of this study is to explore the effectiveness and safety of high dose dexamethasone treatment for Acute Respiratory Distress Syndrome secondary to SARS-Cov-2 pneumonia. Trial design Multicentre, randomized clinical trial, controlled, open label, parallel group, to evaluate the effectiveness and safety of high dose dexamethasone in adult patients with confirmed COVID-19, with Acute Respiratory Distress Syndrome. Participants We will include patients with SARS-Cov-2 pneumonia who develop acute respiratory distress syndrome, in several intensive care units (ICU) in Buenos Aires, Argentina (CEMIC, Clinica Bazterrica, Sanatorio Sagrado Corazon) Inclusion criteria: Men and women, age ≥ 18 years old. Confirmed diagnosis of SARS-CoV-2 infection, by RT-PCR. Diagnosis of Acute Respiratory Distress Syndrome (hypoxemic respiratory failure not explained by cardiac disease + PaO2/FiO2 ratio < 300 with a Positive End-Expiratory Pressure ≥ 5 cm H2O + bilateral pulmonary infiltrates) Length of mechanical ventilation of at least 72 hours Informed consent (next of kin / legal guardian) Exclusion criteria: Pregnant or breast-feeding women. Terminal disease (advanced cancer; under palliative care; cardiovascular, respiratory, or renal disease with a life expectancy less ≤ 1 year). Therapeutic limitation (advance directives or do not resuscitate order) Severe immunosuppression (HIV infection, long-term use of immunosuppressive agents, active cancer). Patients under chronic treatment with glucocorticoids for other diseases (≥ 8 mg prednisone, or equivalent) Participation in another randomized clinical trial. Intervention and comparator Eligible patients will be randomized to receive standard ICU patient care (group 1) or standard ICU patient care plus high dose dexamethasone (group 2). Group 1: dexamethasone up to 6 mg/24 hours for up to 10 days + ventilatory, hemodynamic, nutritional, and antimicrobial support according to international guidelines. Group 2: dexamethasone 16 mg/24 hours for 5 days followed by dexamethasone 8 mg/24 hours for 5 days + ventilatory, hemodynamic, nutritional, and antimicrobial support according to international guidelines. Main outcome The main result is ventilator-free days at 28 days (Days without ventilator support in the first 28 days following randomization). Secondary outcomes are 28-days and 90-days mortality, frequency of nosocomial infections in the first 28 days after randomization, Sequential Organ Failure Assessment (SOFA) score variation and prone position in the first 10-days, viral shedding 28-days after randomization, and delirium and muscle weakness at ICU discharge. Randomisation Treatment will be assigned according to site stratified randomization by permuted random blocks sequence 1:1 generated with a table in R language concealed in a randomization tool in REDCap (Research Electronic Data CAPture) platform. Blinding (masking) This is an open trial, so no masking of treatment assignment will be used. Numbers to be randomised (sample size) Assuming a 3 days difference in ventilator-free days between treatment groups, with a mean of 9 days, and a standard deviation of 9 days; the necessary sample size would be 284 subjects (142 per group), with a power of 80% and a two-tailed alpha error of 0.05. Trial Status The protocol with code 1264, version 3.0 on date: May 13, 2020 is approved by the local Ethics Committee. The trial is in the recruitment phase. Recruitment began May 22, 2020 and is anticipated to be complete by the end of December 2021. Trial registration The trial was registered under the title “Dexamethasone for COVID-19 Related ARDS: a Multicenter, Randomized Clinical Trial” with ClinicalTrials number NCT04395105, https://clinicaltrials.gov/ct2/show/NCT04395105, registered on 20 May 2020. Full protocol The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Objectives The new Sepsis-3 definitions have been scarcely assessed in low- and middle-income countries; besides, regional information of sepsis outcomes is sparse. Our objective was to evaluate Sepsis-3 definition performance in Argentina. Design Cohort study of 3-month duration beginning on July 1, 2016. Settings Forty-nine ICUs. Patients Consecutive patients admitted to the ICU with suspected infection that triggered blood cultures and antibiotic administration. Interventions None. Measurements and main results Patients were classified as having infection, sepsis (infection + change in Sequential Organ Failure Assessment ≥ 2 points), and septic shock (vasopressors + lactate > 2 mmol/L). Patients on vasopressors and lactate less than or equal to 2 mmol/L (cardiovascular dysfunction) were analyzed separately, as those on vasopressors without serum lactate measurement. Systemic inflammatory response syndrome was also recorded. Main outcome was hospital mortality. Of 809 patients, 6% had infection, 29% sepsis, 20% cardiovascular dysfunction, 40% septic shock, and 3% received vasopressors with lactate unmeasured. Hospital mortality was 13%, 20%, 39%, 51%, and 41%, respectively (p = 0.000). Independent predictors of outcome were lactate, Sequential Organ Failure Assessment score, comorbidities, prior duration of symptoms (hr), mechanical ventilation requirement, and infection by highly resistant microorganisms. Area under the receiver operating characteristic curves for mortality for systemic inflammatory response syndrome and Sequential Organ Failure Assessment were 0.53 (0.48-0.55) and 0.74 (0.69-0.77), respectively (p = 0.000). Conclusions Increasing severity of Sepsis-3 categories adequately tracks mortality; cardiovascular dysfunction subgroup, not included in Sepsis-3, has distinct characteristics. Sequential Organ Failure Assessment score shows adequate prognosis accuracy-contrary to systemic inflammatory response syndrome. This study supports the predictive validity of Sepsis-3 definitions.

There is considerable evidence on the direct relationship between higher volume and lower mortality in the pancreatoduodenectomy (DPC). However, there is little evidence of morbidity and mortality in the process of building a high-volume pancreatic surgery center. Objective. To evaluate the morbidity and mortality of the DPC in the process of building a high-volume center for pancreatic resection.All consecutive patients undergoing DPC from July 2007 through July 2009 at a single center were included. High volume center was defined as that doing more than 19 DPC per year and high volume surgeon as that doing 16 or more DPC per year. The analysis of data was carried out in two periods according to the number of DPC per year: the first (1998 to 2005) as low volume center and the second (2006 to 2012) as high volume center.Three hundred and thirty five DPC were conducted consecutively. All surgeries were performed by a high volume surgeon. One hundred and seven patients were operated in the first period and 228 in the second period. There were no significant differences in morbidity and mortality between the both periods. In the second period there were significantly less operative time and minor length ofstay.High volume surgeons in pancreatic surgery can transfer their experience to the creation of a high volume pancreatic surgery center without sacrificing the morbidity and mortality.

Objective The purpose of this study is to determine the incidence, risk factors, and outcome of ventilator-associated pneumonia (VAP). Design Prospective cohort. Setting Three hundred sixty-one intensive care units (ICUs) from 20 countries. Patients and Participants Two thousand eight hundred ninety-seven patients mechanically ventilated for more than 12 hours. Measurements and Results Baseline demographic data, primary indication for mechanical ventilation, daily ventilator settings, multiple organ failure over the course of mechanical ventilation, and outcome were collected. Ventilator-associated pneumonia was present in 439 patients (15%). Patients with VAP were more likely to have chronic pulmonary obstructive disease, aspiration, sepsis, and acute respiratory distress syndrome. Mortality in patients with VAP was 38%. Factors associated with mortality were severity of illness, limited activity before the onset of mechanical ventilation and development of shock, acute renal failure, and worsening of hypoxemia during the period of mechanical ventilation. Case-control analysis showed no increased mortality in patients with VAP (38.1% vs 37.9%, P = .95) but prolonged duration of mechanical ventilation and ICU stay. Conclusion In a large cohort of mechanically ventilated patients, VAP is more likely in patients with underlying lung disease (acute or chronic). Ventilator-associated pneumonia was associated with a significant increase in ICU length of stay but no increase in mortality.

Objective To determine if measurements of gastric intramucosal pH have prognostic implications regarding ICU mortality. Design Prospective comparison of outcome. Setting General adult ICUs in two teaching hospitals. Patients Eighty consecutive patients age 18 to 84 yrs (mean 63.4), 50 men and 30 women, 55% in the medical and 45% in the surgical services. Methods Gastric intramucosal pH was measured on ICU admission and again 12 hrs later. A value of greater than or equal to 7.35 was used to differentiate between normal and low gastric intramucosal pH. Measurements and main results Fifty-four patients had a normal gastric intramucosal pH and 26 patients had a low gastric intramucosal pH on ICU admission. The mortality rate was greater in the low gastric intramucosal pH group (65.4% vs. 43.6%; p less than .04). The frequency of sepsis and the presence of multisystem organ failure also were greater in the low gastric intramucosal pH group (p less than .01). Further stratification of patients according to gastric intramucosal pH measured 12 hrs after admission showed a greater mortality rate in patients with persistently low gastric intramucosal pH when compared with patients with normal gastric intramucosal pH during the first 12 hrs (86.7% vs. 26.8%; p less than .001). Conclusions Measurements of gastric intramucosal pH on ICU admission, and again 12 hrs later, have a high specificity for predicting patient survival in this ICU patient population (77.8% to 80.6%). Furthermore, given its relative noninvasive nature, tonometrically measured gastric intramucosal pH may be a useful addition to patient monitoring in the ICU.

We measured skeletal muscle tissue PO2 (PtO2) in anesthetized rabbits (n = 7) following infusion of an intravenous bolus of E coli endotoxin. An array of surface PO2 microelectrodes was placed over the hindlimb biceps femoris muscle and sufficient readings were obtained to construct a PtO2 histogram. Changes in the histogram standard deviation were used to characterize micro-circulatory maldistribution. Systemic O2 consumption (VO2) was measured by the expired gas method. Cardiac output (Q) and systemic O2 transport (TO2) were calculated. Samples of arterial, right atrial (ra), and hindlimb venous blood, from a catheter placed in the infrarenal portion of the vena cava, were simultaneously obtained for measurement of blood gases and saturations. Following the administration of endotoxin, there were decreases in Q and TO2 of approximately 50 percent. The VO2 initially decreased 23 percent, but returned to baseline levels 30 minutes after endotoxin administration. Systemic O2 extraction ratio (ERO2 = VO2/TO2) increased from 0.32 +/- .03 to 0.54 +/- .07 (p less than 0.01), whereas hindlimb ERO2 increased from 0.42 +/- .03 to 0.60 +/- .02 (p less than 0.01). The arithmetic mean of the PtO2 histograms decreased after endotoxin infusion (43 +/- 4 to 7 +/- 2 mm Hg; p less than 0.01), but PLO2 remained at baseline levels (35 +/- 2 vs. 33 +/- 2 mm Hg; p = NS). The standard deviation of the PtO2 histograms remained constant during the experiment. This finding supports the notion that skeletal muscle microcirculatory heterogeneity does not increase during endotoxin induced hypodynamic sepsis.

Objetivo. Determinar las variables asociadas con el pronóstico de los enfermos con agudización de la enfermedad pulmonar obstructiva crónica que requieren ventilación mecánica. Diseño. Estudio prospectivo de cohortes con análisis retrospectivo. Ámbito. Trescientas sesenta y una Unidades de Cuidados Intensivos (UCI) de 20 países. Pacientes y métodos. Se incluyeron en el estudio a 522 pacientes que precisan ventilación mecánica durante más de 12 horas debido a una agudización de la enfermedad pulmonar obstructiva crónica. Para la estimación de las variables asociadas a la mortalidad se realizó un análisis de particiones recursivas, donde se incluyeron las siguientes variables: demográficas, gases arteriales previos a la intubación, complicaciones aparecidas durante la ventilación mecánica (barotrauma, síndrome de distrés respiratorio agudo, neumonía asociada a la ventilación mecánica, sepsis), disfunción de órganos (cardiovascular, renal, hepático, coagulación) y duración del soporte ventilatorio. Intervenciones. Ninguna. Variables de interés principales. Mortalidad en la UCI. Resultados. La mortalidad en la UCI fue de un 22% y en el hospital de un 30%. Las variables asociadas a la mortalidad fueron la disfunción cardiovascular, la disfunción renal y una duración del soporte ventilatorio de más de 18 días. La mediana de la duración de la ventilación mecánica fue de 4 días (P25: 2, P75: 6), de desconexión de la ventilación mecánica de 2 días (P25: 1, P75: 5), de estancia en la UCI de 8 días (P25: 5, P75: 13) y de estancia en el hospital de 17 días (P25: 10, P75: 27). Conclusiones. En nuestra cohorte de enfermos con enfermedad pulmonar obstructiva crónica que requieren ventilación mecánica la mortalidad se asoció a disfunción cardiovascular, renal y necesidad de soporte ventilatorio prolongado. Objetive. To determine the variables associated with prognosis for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in mechanically ventilated patients. Dsign. Prospective cohort study with retrospective analysis. Location. 361 Intensive Care Units (ICU) in 20 countries. Patients and methods. There were included in the study 522 patients who required mechanical ventilation for more than 12 hours due to an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). In order to determine those variables associated with mortality, there was performed a recursive partition analysis in which the following variables were included: demographics, arterial blood gas prior to intubation, complications arising during mechanical ventilation (barotrauma, acute respiratory distress syndrome, ventilator-associated pneumonia, sepsis), organ dysfunction (cardiovascular, renal, liver, coagulation) and duration of ventilatory support. Interventions. None. Variables of prime importance. ICU mortality. Results. ICU and hospital mortality rates were 22% and 30%, respectively. Variables associated with mortality were cardiovascular dysfunction, renal dysfunction and duration of ventilatory support > 18 days. Median durations were as follows: mechanical ventilatory support, 4 days (P25: 2, P75: 6); weaning from ventilatory support, 2 days (P25: 1, P75: 5); stay in intensive care unit, 8 days (P25: 5, P75: 13); stay in hospital, 17 days (P25: 10, P75: 27). Conclusions. Mortality in the studied cohort of patients with AECOPD was associated with cardiovascular dysfunction, renal dysfunction and prolonged mechanical support.

To evaluate the variables associated with mortality of patients with community-acquired pneumonia who require mechanical ventilation and to determine the attributable morbidity and intensive care unit (ICU) mortality of community-acquired pneumonia.Retrospective cohort study carried out in 361 ICUs from 20 countries including 124 patients who required mechanical ventilation on the first day of admission to the hospital due to acute respiratory failure secondary to severe community-acquired pneumonia. To assess the factors associated with outcome, a forward stepwise logistic regression analysis was performed, and to determine the attributable mortality of community-acquired pneumonia, a matched study design was used.We found 3 independent variables significantly associated with death in patients with community-acquired pneumonia requiring mechanical ventilation: simplified acute physiological score greater than 45 (odds ratio, 5.5 [95% confidence interval, 1.7-12.3]), shock (odds ratio, 5.7 [95% confidence interval, 1.7-10.1]), and acute renal failure (odds ratio, 3.0 [95% confidence interval, 1.1-4.0]). There was no statistically significant difference in ICU mortality among patients with or without community-acquired pneumonia (32% vs 35%; P=.59).Community-acquired pneumonia needing mechanical ventilation is not a disease associated with higher mortality. The main determinants of patient outcome were initial severity of illness and the development of shock and/or acute renal failure.

As in other critical care fields, the past 5 years have been rich with good news about adult respiratory distress syndrome (ARDS). New epidemiologic data concerning incidence and outcome in different countries have been published. Components of the ARDS definition are being clarified. The influence of genetics is beginning to be studied. Risk factors are grouped according to pathophysiologic characteristics. Techniques such as computed tomography (CT) not only give data about lung morphology in different stages of ARDS, but also provide information about response to therapy. Mechanisms of repair continue to be clarified. And, above all, there are new insights about essential supportive therapy, mechanical ventilation. Limitation of tidal volumes has been associated with an improved outcome, possibly because of protecting from overdistention and subsequent ventilator-induced lung injury. New methods to titrate positive end-expiratory pressure (PEEP) have been proposed, but none has shown a clear advantage over the others. PEEP has been associated with a protective effect against ventilator-induced lung injury (VILI), well demonstrated in experimental studies but still uncertain in clinical trials. Of the new adjunctive measures for mechanical ventilation, prone positioning and recruitment maneuvers have been most extensively studied, especially with regard to their mechanisms of action, and are physiologically appealing. Prone positioning is an inexpensive and effective method for reversing hypoxemia, but effects on mortality have not been demonstrated, possibly because the timing and duration of this adjuvant have not been established yet. Recruitment maneuvers are starting to be used in the clinical arena; data about optimal frequency, duration, magnitude, and impact on outcome are still lacking.

To determine the incidence, risk factors, and outcome of barotrauma in a cohort of mechanically ventilated patients where limited tidal volumes and airway pressures were used.Prospective cohort of 361 intensive care units from 20 countries.A total of 5183 patients mechanically ventilated for more than 12 h.Baseline demographic data, primary indication for mechanical ventilation, daily ventilator settings, multiple-organ failure over the course of mechanical ventilation and outcome were collected. Barotrauma was present in 154 patients (2.9%). The incidence varied according to the reason for mechanical ventilation: 2.9% of patients with chronic obstructive pulmonary disease; 6.3% of patients with asthma; 10.0% of patients with chronic interstitial lung disease (ILD); 6.5% of patients with acute respiratory distress syndrome (ARDS); and 4.2% of patients with pneumonia. Patients with and without barotrauma did not differ in any ventilator parameter. Logistic regression analysis identified as factors independently associated with barotrauma: asthma [RR 2.58 (1.05-6.50)], ILD [RR 4.23 (95%CI 1.78-10.03)]; ARDS as primary reason for mechanical ventilation [RR 2.70 (95%CI 1.55-4.70)]; and ARDS as a complication during the course of mechanical ventilation [RR 2.53 (95%CI 1.40-4.57)]. Case-control analysis showed increased mortality in patients with barotrauma (51.4 vs 39.2%; p=0.04) and prolonged ICU stay.In a cohort of patients in whom airway pressures and tidal volume are limited, barotrauma is more likely in patients ventilated due to underlying lung disease (acute or chronic). Barotrauma was also associated with a significant increase in the ICU length of stay and mortality.

To prospectively evaluate the performance of the Clinical Pulmonary Infection Score (CPIS) and its components to identify early in the hospital course of ventilator-associated pneumonia (VAP) which patients are responding to therapy.Prospective, multicenter, in a cohort of mechanically ventilated patients.The intensive care unit of six hospitals located in the metropolitan area of Buenos Aires, Argentina.Sixty-three patients, from a cohort of 472 mechanically ventilated patients hospitalized for72 hrs, had clinical evidence of VAP and bacteriologic confirmation by bronchoalveolar lavage (BAL) or blood cultures.Bronchoscopy with BAL fluid culture and blood cultures after establishing a clinical diagnosis of VAP. All patients received antibiotics, 46 before bronchoscopy and 17 immediately after bronchoscopy.CPIS was measured at 3 days before VAP (VAP-3); at the onset of VAP (VAP); and at 3 (VAP+3), 5 (VAP+5), and 7 (VAP+7) days after onset. CPIS rose from VAP-3 to VAP and then fell progressively in the population as a whole (p.001), and the fall in CPIS was significant in 31 survivors, but not in 32 nonsurvivors. From the individual components of the CPIS, only the Pao /Fio ratio distinguished survivors from nonsurvivors, beginning at VAP+3. When CPIS was6 at 3 or 5 days after VAP onset, mortality was lower than in the remaining patients (p =.018). These differences also related to the finding that those receiving adequate therapy had a slight fall in CPIS and a significant increase of Pao /Fio at VAP+3, whereas those getting inadequate therapy did not.Serial measurements of CPIS can define the clinical course of VAP resolution, identifying those with good outcome as early as day 3, and could possibly be of help to define strategies to shorten the duration of therapy.

Objectives: (1) To demonstrate that metabolic parameters are better indicators of tissue hypoxia than regional and whole oxygen consumption (VO2). (2) To compare intramucosal pH (pHi) in different gastrointestinal segments. Design: Prospective, interventional study. Setting: Research laboratory at a university center. Subjects: Fourteen anesthetized, mechanically ventilated dogs. Interventions: Twenty milliliters per kilogram bleeding. Measurements and main results: We placed pulmonary, aortic and mesenteric venous catheters, and an electromagnetic flow probe in the superior mesenteric artery, and gastric, jejunal and ileal tonometers to measure flows, arterial and venous blood gases and lactate, and intramucosal PCO2. We calculated systemic and intestinal oxygen transport (DO2) and consumption (VO2), pHi and arterial minus intramucosal PCO2 (ΔPCO2). Then, we bled the dogs and repeated the measurements after 30 min. Systemic and intestinal DO2 fell (26.0±7.3 versus 8.9±2.6 and 71.9±17.3 versus 24.6±9.6 ml/min per kg, respectively, p, Facultad de Ciencias Médicas

Objectives: To examine the relationship between end-tidal CO2 (PETCO2) and its physiological determinants, pulmonary blood flow (cardiac output, CO) and CO2 production (VCO2), in a model of hemorrhagic shock during fixed minute ventilation. Design and setting: Prospective, observational study in a research laboratory at a university center. Subjects and interventions: Six anesthetized, intubated, and mechanically ventilated mongrel dogs. Progressive stepwise bleeding. Measurements and results: We continuously measured PETCO2 with a capnograph, pulmonary artery blood flow with an electromagnetic flow probe, arterial oxygen saturation (SaO2) with a fiberoptic catheter, and oxygen consumption (VO2) and VCO2 by expired gases analysis. Oxygen delivery (DO2) was continuously calculated from pulmonary blood flow and SaO2. We studied the correlation of PETCO2 with CO and VCO2 in each individual experiment. We also calculated the critical point in the relationships PETCO2/DO2 and VO2/DO2 by the polynomial method. As expected, PETCO2 was correlated with CO. The best fit was logarithmic in all experiments (median r 2=0.90), showing that PETCO2 decrease is greater in lowest flow states. PETCO2 was correlated with VCO2, but the best fit was linear (median r 2=0.77). Critical DO2 for PETCO2 and VO2 was 8.0±3.3 and 6.3±2.5 ml.min–1.kg–1, respectively (NS). Conclusions: Our data reconfirm the relationship between PETCO2 and CO during hemorrhagic shock. The relatively greater decrease in PETCO2 at lowest CO levels could represent diminished CO2 production during the period of VO2 supply dependency., Facultad de Ciencias Médicas

Falls in gastric intramucosal pH (pHi) are associated with morbidity and mortality in patients admitted to intensive-care units (ICU). We tested the hypothesis that ICU outcome can be improved by therapy guided by changes in pHi and aimed at improving systemic oxygen availability. We studied 260 patients admitted to ICUs with APACHE II scores of 15-25. After insertion of a gastric tonometer, each patient was randomly assigned to a control or protocol group within the admission pHi category (normal = 7.35 or higher; low = below 7.35). The control groups were treated according to standard ICU practices. The protocol groups received, in addition, treatment to increase systemic oxygen transport or to reduce oxygen demand, whenever the pHi fell below 7.35 or by more than 0.10 units from the previous measurement. The protocol was used, because pHi fell, in 67 (85%) of the protocol group with normal pHi on admission. There were no significant differences between protocol and control groups in demographic characteristics, admission blood gases or haemoglobin concentration, number or type of organ system failures, or the intensity of ICU care. For patients admitted with low pHi, survival was similar in the protocol and control groups (37% vs 36%), whereas for those admitted with normal pHi, survival was significantly greater in the protocol than in the control group (58% vs 42%; p less than 0.01). Therapy guided by pHi measurements improved survival in patients whose pHi on admission to ICU was normal. pHi-guided resuscitation may help improve outcome in such patients by preventing splanchnic organ hypoxia and the development of a systemic oxygen deficit.

Introduction: Resuscitation goals for septic shock remain controversial. Despite the normalization of systemic hemodynamic variables, tissue hypoperfusion can still persist. Indeed, lactate or oxygen venous saturation may be difficult to interpret. Our hypothesis was that a gastric intramucosal pH-guided resuscitation protocol might improve the outcome of septic shock compared with a standard approach aimed at normalizing systemic parameters such as cardiac index (CI). Methods: The 130 septic-shock patients were randomized to two different resuscitation goals: CI ≥ 3.0 L/min/m2 (CI group: 66 patients) or intramucosal pH (pHi) ≥ 7.32 (pHi group: 64 patients). After correcting basic physiologic parameters, additional resuscitation consisting of more fluids and dobutamine was started if specific goals for each group had not been reached. Several clinical data were registered at baseline and during evolution. Hemodynamic data and pHi values were registered every 6 hours during the protocol. Primary end point was 28 days' mortality. Results: Both groups were comparable at baseline. The most frequent sources of infection were abdominal sepsis and pneumonia. Twenty-eight day mortality (30.3 vs. 28.1%), peak Therapeutic Intervention Scoring System scores (32.6 ± 6.5 vs. 33.2 ± 4.7) and ICU length of stay (12.6 ± 8.2 vs. 16 ± 12.4 days) were comparable. A higher proportion of patients exhibited values below the specific target at baseline in the pHi group compared with the CI group (50% vs. 10.9%; P < 0.001). Of 32 patients with a pHi < 7.32 at baseline, only 7 (22%) normalized this parameter after resuscitation. Areas under the receiver operator characteristic curves to predict mortality at baseline, and at 24 and 48 hours were 0.55, 0.61, and 0.47, and 0.70, 0.90, and 0.75, for CI and pHi, respectively. Conclusions: Our study failed to demonstrate any survival benefit of using pHi compared with CI as resuscitation goal in septic-shock patients. Nevertheless, a normalization of pHi within 24 hours of resuscitation is a strong signal of therapeutic success, and in contrast, a persistent low pHi despite treatment is associated with a very bad prognosis in septic-shock patients., Facultad de Ciencias Médicas

Introduction An elevation in intramucosal–arterial PCO2 gradient (ΔPCO2) could be determined either by tissue hypoxia or by reduced blood flow. Our hypothesis was that in hypoxic hypoxia with preserved blood flow, ΔPCO2 should not be altered.

Our goal was to compare measurement of tonometered saline and gastric juice partial carbon dioxide tension (PCO2). In this prospective observational study, 112 pairs of measurements were simultaneously obtained under various hemodynamic conditions, in 15 critical care patients. Linear regression analysis showed a significant correlation between the two methods of measuring PCO2 (r2 = 0.43; P < 0.0001). However, gastric juice PCO2 was systematically higher (mean difference 51 mmHg). The 95% limits of agreement were 315 mmHg and the dispersion increased as the values of PCO2 increased. Tonometric and gastric juice PCO2 cannot be used interchangeably. Gastric juice PCO2 measurement should be interpreted with caution.