Core competencies in critical care for general medical practitioners in South Africa: A Delphi study.

Background: Despite a high burden of disease that requires critical care services, there are a limited number of intensivists in South Africa (SA). Medical practitioners at district and regional public sector hospitals frequently manage critically ill patients in the absence of intensivists, despite these medical practitioners having had minimal exposure to critical care during their undergraduate training. Objectives: To identify core competencies in critical care for medical practitioners who provide critical care services at public sector hospitals in SA where intensivists are not available to direct patient management. Methods: A preliminary list of core competencies in critical care was compiled. Thereafter, 13 national and international experts were requested to achieve consensus on a final list of core competencies that are required for critical care by medical practitioners, using a modified Delphi process. Results: A final list of 153 core competencies in critical care was identified. Conclusion: The core competencies identified by this study could assist in developing training programmes for medical practitioners to improve the quality of critical care services provided at district and regional hospitals in SA. Contribution of the study: The study provides consensus on a list of core competencies in critical care that non-intensivist medical practitioners managing critically ill patients in healthcare settings in South Africa, especially where intensivists are not readily available, should have. The list can form the core content of training programmes aimed at improving critical care competence of general medical practitioners, and in this way hopefully improve the overall outcomes of critically ill patients in South Africa.

The effect of fluid bolus administration on cerebral tissue oxygenation in post-cardiac arrest patients.

PURPOSE: Fluid boluses (FB) are often used in post-cardiac arrest (CA) patients with haemodynamic instability. Although FB may improve cardiac output (CO) and mean arterial pressure (MAP), FB may also increase central venous pressure (CVP), reduce arterial PaO2, dilute haemoglobin and cause interstitial oedema. The aim of the present study was to investigate the net effect of FB administration on cerebral tissue oxygenation saturation (SctO2) in post-CA patients. METHODS: Pre-planned sub-study of the Neuroprotect post-CA trial (NCT02541591). Patients with anticipated fluid responsiveness based on stroke volume variation (SVV) or passive leg raising test were administered a FB of 500 ml plasma-lyte A (Baxter Healthcare) and underwent pre- and post-FB assessments of stroke volume, CO, MAP, CVP, haemoglobin, PaO2 and SctO2. RESULTS: 52 patients (mean age 64 ±â€¯12 years, 75% male) received a total of 115 FB. Although administration of a FB resulted in a significant increase of stroke volume (63 ±â€¯22 vs 67 ±â€¯23 mL, p = 0.001), CO (4,2 ±â€¯1,6 vs 4,4 ±â€¯1,7 L/min, p = 0.001) and MAP (74,8 ±â€¯13,2 vs 79,2 ±â€¯12,9 mmHg, p = 0.004), it did not improve SctO2 (68.54 ±â€¯6.99 vs 68.70 ±â€¯6.80%, p = 0.49). Fluid bolus administration also resulted in a significant increase of CVP (10,0 ±â€¯4,5 vs 10,7 ±â€¯4,9 mmHg, p = 0.02), but did not affect PaO2 (99 ±â€¯31 vs 94 ±â€¯31 mmHg, p = 0.15) or haemoglobin concentrations (12,9 ±â€¯2,1 vs 12,8 ±â€¯2,2 g/dL, p = 0.10). In a multivariate model, FB-induced changes in CO (beta 0,77; p = 0.004) and in CVP (beta -0,23; p = 0.02) but not in MAP (beta 0,02; p = 0.18) predicted post-FB ΔSctO2. CONCLUSIONS: Despite improvements in CO and MAP, FB administration did not improve SctO2 in post-cardiac arrest patients.

MECCIAS trial: Metabolic consequences of continuous veno-venous hemofiltration on indirect calorimetry.

BACKGROUND: and aims: Caloric prescription based on resting energy expenditure (REE) measured with indirect calorimetry (IC) improves outcome and is the gold standard in nutritional therapy of critically ill patients. Until now continuous renal replacement therapy (CRRT) precluded the use of IC due to several mechanisms. We investigated the impact of CRRT on V̇CO2, V̇O2 and REE to facilitate indirect calorimetry during CRRT. METHODS: In 10 critically ill ventilated patient in need of continuous veno-venous hemofiltration (CVVH) using citrate predilution we performed IC in 4 different states: baseline, high dose, baseline with NaCl predilution and without CVVH. CO2 content of effluent fluid was measured by a point of care blood gas analyzer. Carbon dioxide production (V̇CO2) measured with IC was adapted by adding the CO2 flow of effluent and deducing CO2 flow in postdilution fluid to calculate a true V̇CO2. True REE was calculated with the Weir equation using the true V̇CO2. RESULTS: CO2 removal in effluent during baseline, high dose and NaCl predilution was respectively 24 mL/min, 38 mL/min and 23 mL/min. Together with the CO2 delivery by the postdilution fluid this led to an adaptation of REE respectively by 34 kcal/d or 2% (p = 0,002), 44 kcal/d or 3% (p = 0,002) and 33 kcal/d or 2% (p = 0,002). Compared to the true REE during baseline of 1935 ± 921 kcal/d, true REE during high dose was 1723 ± 752 kcal/d (p = 0.65), during NaCl predilution it was 1604 ± 633 kcal/d (p = 0.014) and without CRRT it was 1713 ± 704 kcal/d (p = 0.193). CONCLUSIONS: CO2 alterations due to CVVH are clinically of no importance so no correction factor of REE is needed with or without CVVH. IC must be performed during CVVH as CVVH seems to alter metabolism. These changes may be mainly explained by the use of citrate predilution.

Energy expenditure and caloric targets during continuous renal replacement therapy under regional citrate anticoagulation. A viewpoint.

BACKGROUND: Indirect calorimetry (IC) is the gold standard for measuring energy expenditure in critically ill patients However, continuous renal replacement therapy (CRRT) is a formal contraindication for IC use. AIMS: To discuss specific issues that hamper or preclude an IC-based assessment of energy expenditure and correct caloric prescription in CRRT-treated patients. METHODS: Narrative review of current literature. RESULTS: Several relevant pitfalls for validation of IC during CRRT were identified. First, IC measures CO2 production (VCO2) and O2 consumption to calculate resting energy expenditure (REE) with the Weir equation. VCO2 measurements are influenced by CRRT because CO2 is exchanged during the blood purification process. CO2 exchange also depends on type of pre- and/or postdilution fluid(s). CO2 dissolves in different forms with dynamic but unpredictable impact on VCO2. Second, the effect of immunologic activation and heat loss on REE caused by extracorporeal circulation during CRRT is poorly documented. Third, caloric prescription should be adapted to CRRT-induced in- and efflux of different nutrients. Finally, citrate, which is the preferred anticoagulant for CRRT, is a caloric source that may influence IC measurements and REE. CONCLUSION: Better understanding of CRRT-related processes is needed to assess REE and provide individualized nutritional therapy in this condition.

Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers.

BACKGROUND.: Daily and globally, millions of adult hospitalized patients are exposed to maintenance i.v. fluid solutions supported by limited scientific evidence. In particular, it remains unclear whether fluid tonicity contributes to the recently established detrimental effects of fluid, sodium, and chloride overload. METHODS.: This crossover study consisted of two 48 h study periods, during which 12 fasting healthy adults were treated with a frequently prescribed solution (NaCl 0.9% in glucose 5% supplemented by 40 mmol litre -1 of potassium chloride) and a premixed hypotonic fluid (NaCl 0.32% in glucose 5% containing 26 mmol litre -1 of potassium) at a daily rate of 25 ml kg -1 of body weight. The primary end point was cumulative urine volume; fluid balance was thus calculated. We also explored the physiological mechanisms behind our findings and assessed electrolyte concentrations. RESULTS.: After 48 h, 595 ml (95% CI: 454-735) less urine was voided with isotonic fluids than hypotonic fluids ( P <0.001), or 803 ml (95% CI: 692-915) after excluding an outlier with 'exaggerated natriuresis of hypertension'. The isotonic treatment was characterized by a significant decrease in aldosterone ( P <0.001). Sodium concentrations were higher in the isotonic arm ( P <0.001), but all measurements remained within the normal range. Potassium concentrations did not differ between the two solutions ( P =0.45). Chloride concentrations were higher with the isotonic treatment ( P <0.001), even causing hyperchloraemia. CONCLUSIONS.: Even at maintenance rate, isotonic solutions caused lower urine output, characterized by decreased aldosterone concentrations indicating (unintentional) volume expansion, than hypotonic solutions and were associated with hyperchloraemia. Despite their lower sodium and potassium content, hypotonic fluids were not associated with hyponatraemia or hypokalaemia. CLINICAL TRIAL REGISTRATION.: ClinicalTrials.gov (NCT02822898) and EudraCT (2016-001846-24).

Mechanical Intestinal Obstruction in a Porcine Model: Effects of Intra-Abdominal Hypertension. A Preliminary Study.

INTRODUCTION: Mechanical intestinal obstruction is a disorder associated with intra-abdominal hypertension and abdominal compartment syndrome. As the large intestine intraluminal and intra-abdominal pressures are increased, so the patient's risk for intestinal ischaemia. Previous studies have focused on hypoperfusion and bacterial translocation without considering the concomitant effect of intra-abdominal hypertension. The objective of this study was to design and evaluate a mechanical intestinal obstruction model in pigs similar to the human pathophysiology. MATERIALS AND METHODS: Fifteen pigs were divided into three groups: a control group (n = 5) and two groups of 5 pigs with intra-abdominal hypertension induced by mechanical intestinal obstruction. The intra-abdominal pressures of 20 mmHg were maintained for 2 and 5 hours respectively. Hemodynamic, respiratory and gastric intramucosal pH values, as well as blood tests were recorded every 30 min. RESULTS: Significant differences between the control and mechanical intestinal obstruction groups were noted. The mean arterial pressure, cardiac index, dynamic pulmonary compliance and abdominal perfusion pressure decreased. The systemic vascular resistance index, central venous pressure, pulse pressure variation, airway resistance and lactate increased within 2 hours from starting intra-abdominal hypertension (p<0.05). In addition, we observed increased values for the peak and plateau airway pressures, and low values of gastric intramucosal pH in the mechanical intestinal obstruction groups that were significant after 3 hours. CONCLUSION: The mechanical intestinal obstruction model appears to adequately simulate the pathophysiology of intestinal obstruction that occurs in humans. Monitoring abdominal perfusion pressure, dynamic pulmonary compliance, gastric intramucosal pH and lactate values may provide insight in predicting the effects on endorgan function in patients with mechanical intestinal obstruction.

A systematic review and individual patient data meta-analysis on intra-abdominal hypertension in critically ill patients: the wake-up project. World initiative on Abdominal Hypertension Epidemiology, a Unifying Project (WAKE-Up!).

Intra-abdominal hypertension (IAH), defined as a pathologically increase in intraabdominal pressure, is commonly found in critically ill patients. While IAH has been associated with several abdominal as well as extra-abdominal conditions, few studies have examined the occurrence of IAH in relation to mortality. The aim of this paper was to evaluate the prognostic role of IAH and its risk factors at admission in critically ill patients across a wide range of settings and countries. An individual patient meta-analysis of all available data and a systematic review of published (in full or as abstract) medical databases and studies between 1996 and June 2012 were performed. The search was limited to "clinical trials" and "randomized controlled trials", "adults", using the terms "intra-abdominal pressure", "intraabdominal hypertension" combined with any of the terms "outcome" and "mortality". All together data on 2707 patients, representing 21 centers from 11 countries was obtained. Data on 1038 patients were not analysed because of the following exclusion criteria: no IAP value on admission (N.=712), absence of information on ICU outcome (N.=195), age <18 or >95 years (N.=131). Data from 1669 individual patients (19 centers from 9 countries) were analyzed in the meta-analysis. Presence of IAH was defined as a sustained increase in IAP equal to or above 12 mmHg. At admission the mean overall IAP was 9.9±5.0 mmHg, with 463 patients (27.7%) presenting IAH with a mean IAP of 16.3±3.4 mmHg. The only independent predictors for IAH were SOFA score and fluid balance on the day of admission. Five hundred thirteen patients (30.8%) died in intensive care. The independent predictors for intensive care mortality were IAH, SAPS II score, SOFA score and admission category. This systematic review and individual patient data meta-analysis shows that IAH is frequently present in critically ill patients and it is an independent predictor for mortality.

Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: A metaanalysis of the literature

Introduction: Hemodynamic parameters such as the global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI), derived by transpulmonary thermodilution, have gained increasing interest for guiding fluid therapy in critically ill patients. The proposed normal values (680-800ml/m2 for GEDVI and 3-7ml/kg for EVLWI) are based on measurements in healthy individuals and on expert opinion, and are assumed to be suitable for all patients. We analyzed the published data for GEDVI and EVLWI, and investigated the differences between a cohort of septic patients (SEP) and patients undergoing major surgery (SURG), respectively. Methods: A PubMed literature search for GEDVI, EVLWI or transcardiopulmonary single/double indicator thermodilution was carried out, covering the period from 1990 to 2010. Intervention: Meta-regression analysis was performed to identify any differences between the surgical (SURG) and non-surgical septic groups (SEP). Results: Data from 1925 patients corresponding to 64 studies were included. On comparing both groups, mean GEDVI was significantly higher by 94ml/m2 (95%CI: [54; 134]) in SEP compared to SURG patients (788ml/m2 95%CI: [762; 816], vs. 694ml/m2, 95%CI: [678; 711], p<0.001). Mean EVLWI also differed significantly by 3.3ml/kg (95%CI: [1.4; 5.2], SURG 7.2ml/kg, 95%CI: [6.9; 7.6] vs. SEP 11.0ml/kg, 95%CI: [9.1; 13.0], p=0.001).Conclusions: The published data for GEDVI and EVLWI are heterogeneous, particularly in critically ill patients, and often exceed the proposed normal values derived from healthy individuals. In the group of septic patients, GEDVI and EVLWI were significantly higher than in the group of patients undergoing major surgery. This points to the need for defining different therapeutic targets for different patient populations (AU)

Introducción: Parámetros hemodinámicos como el índice de volumen diastólico final global (GEDVI) y el índice de agua pulmonar extravascular (EVLWI), obtenidos mediante termodilución transpulmonar, suscitan un interés creciente como guía de la terapia de fluidos en pacientes críticamente enfermos. Los valores normales propuestos (680-800ml/m2 para el GEDVI y 3-7ml/kg para el EVLWI) se basan en mediciones realizadas a individuos sanos y en la opinión de expertos, y se asume que son adecuados para todos los pacientes. Analizamos los datos publicados sobre el GEDVI y el EVLWI e investigamos las diferencias entre una cohorte de pacientes septicémicos (SEP) y pacientes sometidos a cirugía mayor (SURG) respectivamente. Métodos: Se realizó una búsqueda bibliográfica en PubMed de GEDVI, EVLWI o termodilución trasncardiopulmonar de indicador único/doble referida al periodo comprendido entre 1990 y 2010. Intervenciones: Se realizó un análisis de metarregresión para identificar las diferencias entre los grupos quirúrgico (SURG) y no quirúrgico septicémico (SEP). Resultados: Se incluyeron los datos de 1925 pacientes correspondientes a 64 estudios. Al comparar ambos grupos, el GEDVI medio resultó ser significativamente (..) (AU)

Comparison of values in critically ill patients for global end-diastolic volume and extravascular lung water measured by transcardiopulmonary thermodilution: a meta-analysis of the literature.

INTRODUCTION: Hemodynamic parameters such as the global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI), derived by transpulmonary thermodilution, have gained increasing interest for guiding fluid therapy in critically ill patients. The proposed normal values (680-800ml/m(2) for GEDVI and 3-7ml/kg for EVLWI) are based on measurements in healthy individuals and on expert opinion, and are assumed to be suitable for all patients. We analyzed the published data for GEDVI and EVLWI, and investigated the differences between a cohort of septic patients (SEP) and patients undergoing major surgery (SURG), respectively. METHODS: A PubMed literature search for GEDVI, EVLWI or transcardiopulmonary single/double indicator thermodilution was carried out, covering the period from 1990 to 2010. INTERVENTION: Meta-regression analysis was performed to identify any differences between the surgical (SURG) and non-surgical septic groups (SEP). RESULTS: Data from 1925 patients corresponding to 64 studies were included. On comparing both groups, mean GEDVI was significantly higher by 94ml/m(2) (95%CI: [54; 134]) in SEP compared to SURG patients (788ml/m(2) 95%CI: [762; 816], vs. 694ml/m(2), 95%CI: [678; 711], p<0.001). Mean EVLWI also differed significantly by 3.3ml/kg (95%CI: [1.4; 5.2], SURG 7.2ml/kg, 95%CI: [6.9; 7.6] vs. SEP 11.0ml/kg, 95%CI: [9.1; 13.0], p=0.001). CONCLUSIONS: The published data for GEDVI and EVLWI are heterogeneous, particularly in critically ill patients, and often exceed the proposed normal values derived from healthy individuals. In the group of septic patients, GEDVI and EVLWI were significantly higher than in the group of patients undergoing major surgery. This points to the need for defining different therapeutic targets for different patient populations.

Localised abdominal compartment syndrome: bladder-over-gastric pressure ratio (B/G ratio) as a clue to diagnosis.

INTRODUCTION: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been identified as a cause of organ dysfunction and mortality in critically ill patients. The diagnosis of IAH/ACS depends on accurate intra-abdominal pressure (IAP) measurement, which is usually performed via the bladder or the stomach.The aim of this study was to describe cases where intragastric pressure (IGP) and intrabladder pressure (IBP) were measured simultaneously. PATIENTS AND METHODS: After review of medical records, four patients admitted to our ICU department where both IGP and IBP were measured, could be identified. IGP was measured using the Spiegelberg catheter and IBP was measured using the FoleyManometer LV. In all patients, the bladder-over-gastric pressure ratio (B/G ratio) was calculated. RESULTS: In two of four patients, IGP and IBP differed significantly. In one patient the B/G ratio was lower than 1 suggesting a diagnosis of epigastric ACS and in one patient B/G ratio was greater than 1 leading to a diagnosis of pelvic ACS. The latter patient was spared a decompressive laparotomy due to the additional IGP measurement and the subsequent diagnosis of localized ACS. CONCLUSION: The preferred methods for IAP measurement are via the bladder and via the stomach. In some patients, IGP and IBP may differ significantly and this may have clinical implications. Clinicians should be aware of the possibility of localized ACS. In order to identify risk factors and to recommend treatment for localized ACS, further study of simultaneous IGP and IBP measurements are needed.

Global and right ventricular end-diastolic volumes correlate better with preload after correction for ejection fraction.

BACKGROUND: Volumetric monitoring with right ventricular end-diastolic volume indexed (RVEDVi) and global end-diastolic volume indexed (GEDVi) is increasingly being suggested as a superior preload indicator compared with the filling pressures central venous pressure (CVP) or the pulmonary capillary wedge pressure (PCWP). However, static monitoring of these volumetric parameters has not consistently been shown to be able to predict changes in cardiac index (CI). The aim of this study was to evaluate whether a correction of RVEDVi and GEDVi with a measure of the individual contractile reserve, assessed by right ventricular ejection fraction (RVEF) and global ejection fraction, improves the ability of RVEDVi and GEDVi to monitor changes in preload over time in critically ill patients. METHODS: Hemodynamic measurements, both by pulmonary artery and by transcardiopulmonary thermodilution, were performed in 11 mechanically ventilated medical ICU patients. Correction of volumes was achieved by normalization to EF deviation from normal EF values in an exponential fashion. Data before and after fluid administration were obtained in eight patients, while data before and after diuretics were obtained in seven patients. RESULTS: No correlation was found between the change in cardiac filling pressures (DeltaCVP, DeltaPCWP) and DeltaCI (R(2) 0.01 and 0.00, respectively). Further, no correlation was found between DeltaRVEDVi or DeltaGEDVi and DeltaCI (R(2) 0.10 and 0.13, respectively). In contrast, a significant correlation was found between DeltaRVEDVi corrected to RVEF (DeltacRVEDVi) and DeltaCI (R(2) 0.64), as well as between DeltacGEDVi and DeltaCI (R(2) 0.59). An increase in the net fluid balance with +844 + or - 495 ml/m(2) resulted in a significant increase in CI of 0.5 + or - 0.3 l/min/m(2); however, only DeltacRVEDVi (R(2) 0.58) and DeltacGEDVi (R(2) 0.36) correlated significantly with DeltaCI. Administration of diuretics resulting in a net fluid balance of -942 + or - 658 ml/m(2) caused a significant decrease in CI with 0.7 + or - 0.5 l/min/m(2); however, only DeltacRVEDVi (R(2) 0.80) and DeltacGEDVi (R(2) 0.61) correlated significantly with DeltaCI. CONCLUSION: Correction of volumetric preload parameters by measures of ejection fraction improved the ability of these parameters to assess changes in preload over time in this heterogeneous group of critically ill patients.

Recommendations for research from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome.

OBJECTIVE: Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been increasingly recognized in the critically ill over the past decade, and the number of published studies has exploded in recent years. Interpretation of the results and comparison of these studies is difficult, because of incomplete and inconsistent reporting of data and statistics. DESIGN: An international consensus group of multidisciplinary specialists convened at the third World Congress on Abdominal Compartment Syndrome to develop recommendations for research related to the diagnosis and management of IAH and ACS. METHODS: Prior to the conference the authors developed a blueprint for consensus definitions and treatment guidelines which were refined both during and after the conference. RESULTS: Three major types of studies were identified (measurement techniques, epidemiology, and interventions), each with different needs regarding methodology, reporting of data and statistical analysis. CONCLUSIONS: These recommendations are proposed to guide clinical research in the field of IAH and ACS.

What is normal intra-abdominal pressure and how is it affected by positioning, body mass and positive end-expiratory pressure?

PURPOSE: To describe what is defined as normal intra-abdominal pressure (IAP) and how body positioning, body mass index (BMI) and positive end-expiratory pressure (PEEP) affect IAP monitoring. METHODS: A review of different databases was made (Pubmed, MEDLINE (January 1966-June 2007) and EMBASE.com (January 1966-June 2007)) using the search terms of "IAP", "intra-abdominal hypertension" (IAH), "abdominal compartment syndrome" (ACS), "body positioning", "prone positioning", "PEEP" and "acute respiratory distress syndrome" (ARDS). Prior to 1966, we selected older articles by looking at the reference lists displayed in the more recent papers. RESULTS: This review focuses on the concept that the abdomen truly behaves as a hydraulic system. The definitions of a normal IAP in the general patient population and morbidly obese patients are reviewed. Subsequently, factors that affect the accuracy of IAP monitoring, i.e., body position (head of bed elevation, lateral decubitus and prone position) and PEEP, are explored. CONCLUSION: The abdomen behaves as a hydraulic system with a normal IAP of about 5-7 mmHg, and with higher baseline levels in morbidly obese patients of about 9-14 mmHg. Measuring IAP via the bladder in the supine position is still the accepted standard method, but in patients in the semi-recumbent position (head of the bed elevated to 30 degrees and 45 degrees ), the IAP on average is 4 and 9 mmHg, respectively, higher. Future research should be focused on developing and validating predictive equations to correct for supine IAP towards the semi-recumbent position. Small increases in IAP in stable patients without IAH, turned prone, have no detrimental effects. The role of prone positioning in the unstable patient with or without IAH still needs to be established.

Acute intestinal distress syndrome: the importance of intra-abdominal pressure.

This review article will focus primarily on the recent literature on abdominal compartment syndrome (ACS) as well as the definitions and recommendations published by the World Society for the Abdominal Compartment Syndrome (WSACS, www.wsacs.org). The risk factors for intra-abdominal hypertension (IAH) and the definitions regarding increased intra-abdominal pressure (IAP) will be listed, followed by a brief but comprehensive overview of the different mechanisms of end-organ dysfunction associated with IAH. Measurement techniques for IAP will be discussed, as well as recommendations for organ function support in patients with IAH. Finally, noninvasive medical management options for IAH, surgical treatment for ACS and management of the open abdomen will be briefly discussed.