Good morning.
Several interesting studies have been presented at the ESICM meeting in Paris. Some of these have simultaneously been published online.
One such study, attempted to evaluate the risk benefit aspects of stress ulcer prophylaxis (SUP) among critically ill patients. Although SUP is extensively prescribed and is considered as a quality marker for ICU care, concerns have been raised of late about the increased incidence of nosocomial pneumonia and diarrhea attributable to SUP. This study aimed to answer some of those concerns
Krag et al: Pantoprazole in Patients at Risk for Gastrointestinal Bleeding in the ICU. NEJM Oct 24 2018
This was a multi center, blinded RCT carried out in Europe. The authors hypothesized that SUP with Pantoprazole would decrease the incidence of Gastro Intestinal Bleeding while increasing the incidence of nosocomial infections and Myocardial Ischemia.
The patients included in this study had to have atleast one risk factor for clinically important GI bleeding among shock, oral anticoagulant usage, renal replacement therapy, need for mechanical ventilation > 24 hours, history of liver disease or ongoing coagulopathy. Pantoprazole was used as SUP as an intravenous injection of 40 mg diluted in 10ml of 0.9% saline. A matching placebo was used.
The primary end point of interest was 90 day mortality. Secondary end points included clinically important gastrointestinal bleeding, new-onset pneumonia, C. difficile infection, or acute myocardial ischemia. Need for RRT and Mechanical ventilation were also included as end points.
This study was carried out between January 2016 and October 2017, enrolling 3298 patients ( 1645 - pantoprazole 1653 placebo). More than 3/4ths of the patients needed mechanical ventilation and more than 2/3rds required vasopressor support. Median SOFA scores of the cohort was 9. More than half the patients received enteral nutrition on the first day of the trial. Average LOS was 6 days and duration of therapy was 4 days.
At the end of 90 days, approximately 30% of patients in both arms had died. There was no difference between the Pantoprazole and the placebo groups. Clinically important events like gi bleed, infection or myocardial ischemia happened in 21-22% of the patients in both the groups. Specifically, GI bleed occurred in 2.8% of patients receiving pantoprazole and 4.2% patients receiving placebo. This difference was statistically insignificant. There were no serious adverse incidents in either group.
The authors concluded that " 90-day mortality, percentages of days alive without the use of life support, and numbers of patients with clinically important events, infectious adverse events, or serious adverse reactions were similar between those treated with pantoprazole and those who received placebo". At the same time incidence of myocardial ischemia and nosocomial infections were not higher in the pantoprazole group.
My opinion: A serious rethinking has to happen regarding the " routine" use of SUP with Pantoprazole. Although the concerns of harm have been partially allayed, the basis for blanket use for all comers is also under question. If enteral feed can be started on the first day, addition of pantoprazole may not confer any additional benefit.
Wednesday, October 24, 2018
Sunday, October 14, 2018
Early versus Late RRT - Should the paradigm change?
Good morning
This week we discuss the results of the IDEAL - ICU ( The Initiation of Dialysis Early Versus Delayed in the Intensive Care Unit ) study which appears to challenge the benefits of early RRT in the ICU.
Barbar et al Timing of Renal-Replacement Therapy in Patients with Acute Kidney Injury and Sepsis.
N Engl J Med 2018; 379: 1431-42
Acute Kidney Injury is very frequent amongst critically ill septic patients. Attributable mortality is also high. The popular belief is that early aggressive RRT is beneficial in terms of ICU survival and long term recovery of renal function.
The IDEAL ICU multicenter study attempted to evaluate whether initiating RRT as soon as a diagnosis of "Failure" as per RIFLE criteria is made, confers survival advantage to the critically ill patient.
They identified patients who satisfied the criteria to define Failure as per the RIFLE criteria. They then randomized this cohort into those who received RRT as soon as failure was diagnosed and into those in whom RRT was initiated only when metabolic problems or hyperkalemia or fluid overload mandated such therapy.
Originally this study was designed to recruit 800+ patients to show a 10% difference in outcomes with 80% power. The primary end point was 90 day mortality. Secondary outcomes were death at 28 days and at 180 days, RRT free days, ventilator and vasopressor free days at 28 days, ICU and hospital LOS, adverse events during the entire ICU stay, fluid balance in the first 7 days after enrollment; the need for emergency renal-replacement therapy in the delayed strategy group; death of patients in the delayed strategy group in whom at least one criterion for emergency renal-replacement therapy was met; and dependence on renal-replacement therapy at hospital discharge.
The study was stopped midway due to apparent futility of the early RRT strategy. Fluid balance also did not show any beneficial pattern with early RRT. The incidence of metabolic complications was higher in the delayed RRT group. Emergency RRT was needed in 17% of patients in the delayed group ( 41 patients). Twenty eight of the 41 died. The dependence on the RRT at hospital discharge was also not significantly different between the two groups.
The authors concluded that " Among patients with septic shock who had severe acute kidney injury, there was no significant difference in overall mortality at 90 days between patients who were assigned to an early strategy for the initiation of renal-replacement therapy and those who were assigned to a delayed strategy."
My view:
1. We need to think twice before initiating RRT just on the basis of creatinine.
2. Failure may not be the ideal comparator. Injury stage may need to be focused on
3. In the delayed strategy emergency need for RRT could be associated with higher mortality
This week we discuss the results of the IDEAL - ICU ( The Initiation of Dialysis Early Versus Delayed in the Intensive Care Unit ) study which appears to challenge the benefits of early RRT in the ICU.
Barbar et al Timing of Renal-Replacement Therapy in Patients with Acute Kidney Injury and Sepsis.
N Engl J Med 2018; 379: 1431-42
Acute Kidney Injury is very frequent amongst critically ill septic patients. Attributable mortality is also high. The popular belief is that early aggressive RRT is beneficial in terms of ICU survival and long term recovery of renal function.
The IDEAL ICU multicenter study attempted to evaluate whether initiating RRT as soon as a diagnosis of "Failure" as per RIFLE criteria is made, confers survival advantage to the critically ill patient.
They identified patients who satisfied the criteria to define Failure as per the RIFLE criteria. They then randomized this cohort into those who received RRT as soon as failure was diagnosed and into those in whom RRT was initiated only when metabolic problems or hyperkalemia or fluid overload mandated such therapy.
Originally this study was designed to recruit 800+ patients to show a 10% difference in outcomes with 80% power. The primary end point was 90 day mortality. Secondary outcomes were death at 28 days and at 180 days, RRT free days, ventilator and vasopressor free days at 28 days, ICU and hospital LOS, adverse events during the entire ICU stay, fluid balance in the first 7 days after enrollment; the need for emergency renal-replacement therapy in the delayed strategy group; death of patients in the delayed strategy group in whom at least one criterion for emergency renal-replacement therapy was met; and dependence on renal-replacement therapy at hospital discharge.
The study was stopped midway due to apparent futility of the early RRT strategy. Fluid balance also did not show any beneficial pattern with early RRT. The incidence of metabolic complications was higher in the delayed RRT group. Emergency RRT was needed in 17% of patients in the delayed group ( 41 patients). Twenty eight of the 41 died. The dependence on the RRT at hospital discharge was also not significantly different between the two groups.
The authors concluded that " Among patients with septic shock who had severe acute kidney injury, there was no significant difference in overall mortality at 90 days between patients who were assigned to an early strategy for the initiation of renal-replacement therapy and those who were assigned to a delayed strategy."
My view:
1. We need to think twice before initiating RRT just on the basis of creatinine.
2. Failure may not be the ideal comparator. Injury stage may need to be focused on
3. In the delayed strategy emergency need for RRT could be associated with higher mortality
Tuesday, October 9, 2018
Have we found an answer to DVT prophylaxis in Neurosurgical patients
Deep Vein Thrombosis is a well recognized complication amongst hospitalized patients. Providing prophylaxis against DVT is acknowledged as a high impact intervention. Neurosurgical patients ( cranial and spinal) constitute a special cohort. On the one hand the incidence of DVT amongst this population is as high as 40%. On the other hand, use of chemical prophylaxis is viewed with caution and with the fear of producing a major hemorrhage. Mechanical prophylaxis has been used as an alternative. But the relative risk reduction with mechanical prophylaxis is not very high. Several attempts have been made in the past to review literature related to this aspect. But the results have been ambiguous.
Khan et al have carried out the latest meta analysis to answer the question of safety of chemical prophylaxis in relation to neurosurgical patients.
Chemical venous thromboembolism prophylaxis in neurosurgical patients: an updated systematic review and meta-analysis
Nickalus R Khan et al J Neurosurg 129:906–915, 2018
The authors carried out a search of literature to identify studies which evaluated the efficacy and safety of chemical prophylaxis among patients undergoing cranial and spinal surgery. Studies which didn't have a control or placebo arm were not included. The funnel plot of the overall study list appears symmetrical excluding publication bias. A total of 9 studies withstood the methodological scrutiny and were eligible for the meta analysis.
The chemical prophylaxis used in six of the studies included was enoxaparin.
The total patient base for this study was 1232. Chemical prophylaxis showed a significant benefit in preventing DVT when compared to placebo with an OR of 0.51. The absolute risk reduction was 42%. The number needed to treat (NNT) for prevention of DVT was 11. The heterogeneity I2 statistic was 0%.
The incidence of major Intra Cranial Hemorrhage in the treatment group was 2.7% compared to 1.6% in the control group. The OR was 1.42, 95% CI 0.61–3.30 which was not statistically significant. The Forrest plots of both these data is shown below.
The rates of major extra cranial bleeds and overall minor bleeds were also not significantly different.
This study seems to conclude that there is a significant benefit in using chemical prophylaxis in prevention of DVT amongst neurosurgical patients with no significant increase in the incidence of major intra cranial hemorrhage.
My opinion: DVTpharmaco prophylaxis amongst Neurosurgical patients may now be approached with a little more confidence. However, close monitoring is needed.
Khan et al have carried out the latest meta analysis to answer the question of safety of chemical prophylaxis in relation to neurosurgical patients.
Chemical venous thromboembolism prophylaxis in neurosurgical patients: an updated systematic review and meta-analysis
Nickalus R Khan et al J Neurosurg 129:906–915, 2018
The authors carried out a search of literature to identify studies which evaluated the efficacy and safety of chemical prophylaxis among patients undergoing cranial and spinal surgery. Studies which didn't have a control or placebo arm were not included. The funnel plot of the overall study list appears symmetrical excluding publication bias. A total of 9 studies withstood the methodological scrutiny and were eligible for the meta analysis.
The chemical prophylaxis used in six of the studies included was enoxaparin.
The total patient base for this study was 1232. Chemical prophylaxis showed a significant benefit in preventing DVT when compared to placebo with an OR of 0.51. The absolute risk reduction was 42%. The number needed to treat (NNT) for prevention of DVT was 11. The heterogeneity I2 statistic was 0%.
The incidence of major Intra Cranial Hemorrhage in the treatment group was 2.7% compared to 1.6% in the control group. The OR was 1.42, 95% CI 0.61–3.30 which was not statistically significant. The Forrest plots of both these data is shown below.
The rates of major extra cranial bleeds and overall minor bleeds were also not significantly different.
This study seems to conclude that there is a significant benefit in using chemical prophylaxis in prevention of DVT amongst neurosurgical patients with no significant increase in the incidence of major intra cranial hemorrhage.
My opinion: DVTpharmaco prophylaxis amongst Neurosurgical patients may now be approached with a little more confidence. However, close monitoring is needed.
Monday, October 1, 2018
Can Response to Iron therapy in ICU be predicted
Anemia in the Intensive Care Unit is a common problem. Transfusion triggers are getting lower across specialties as discussed last week. Iron infusion therapy is sometimes used to augment the marrow response to the stress of critical illness. But, the effect of iron therapy on reducing the transfusion requirement has not been reported. Litton et al attempted to evaluate the efficacy of Hepcidin in predicting the response to iron therapy and thereby reduce transfusion requirements. This was a nested cohort as a part of the IRONMAN study.
Hepcidin predicts response to IV iron therapy in patients admitted to the intensive care unit: a nested cohort study.
Litton et al. Journal of Intensive Care (2018) 6:60
This was a prospective observational study across four tertiary care Australian ICUs which participated in the IRONMAN study.
The response to Iron therapy among critically ill patients is variable. Hepcidin is an integral part of the iron metabolism and serum levels fall in iron deficiency states.
The primary aim of this study was to determine whether low serum hepcidin concentration could identify a subset of critically ill patients with anaemia in whom IV iron therapy was effective in reducing RBC transfusion requirement.
Septic patients and those with well established Iron deficiency were excluded.
The treatment arm received 500 mg IV ferric carboxy maltose. Hepcidin 25 levels were measured prior to administration of parenteral Iron
A total of 133 patients were included in this study
Majority of the patients were post operative patients predominantly from trauma and cardiothoracic ORs. APACHE II score was 12 and mean SOFA score was 6. Eighty eight patients fell in the lower two tertiles of hepcidin concentration. Half of them received parenteral iron and the other half received placebo. Patients who had lower hepcidin concentration responded to Iron and required lesser packed cell transfusions. Patients who had Hepcidin concentration in the highest tertile did not show any decreased requirement for blood transfusion despite iron therapy. Hepcidin levels did not correlate with standard determinants of iron deficiency like transferrin saturation index.
The authors surmised that serum hepcidin concentration identified a subset of anaemic, critically ill patients in whom IV iron therapy was effective in reducing RBC transfusion requirement.
What I understood?
Predicting response to iron therapy is always difficult and unpredictable. Using the Hepcidin level, if response to therapy can be predicted, lot of blood transfusions can be safely avoided
Where this study fails?
No septic patients included
No correlation with perfusion markers.
Hepcidin predicts response to IV iron therapy in patients admitted to the intensive care unit: a nested cohort study.
Litton et al. Journal of Intensive Care (2018) 6:60
This was a prospective observational study across four tertiary care Australian ICUs which participated in the IRONMAN study.
The response to Iron therapy among critically ill patients is variable. Hepcidin is an integral part of the iron metabolism and serum levels fall in iron deficiency states.
The primary aim of this study was to determine whether low serum hepcidin concentration could identify a subset of critically ill patients with anaemia in whom IV iron therapy was effective in reducing RBC transfusion requirement.
Septic patients and those with well established Iron deficiency were excluded.
The treatment arm received 500 mg IV ferric carboxy maltose. Hepcidin 25 levels were measured prior to administration of parenteral Iron
A total of 133 patients were included in this study
Majority of the patients were post operative patients predominantly from trauma and cardiothoracic ORs. APACHE II score was 12 and mean SOFA score was 6. Eighty eight patients fell in the lower two tertiles of hepcidin concentration. Half of them received parenteral iron and the other half received placebo. Patients who had lower hepcidin concentration responded to Iron and required lesser packed cell transfusions. Patients who had Hepcidin concentration in the highest tertile did not show any decreased requirement for blood transfusion despite iron therapy. Hepcidin levels did not correlate with standard determinants of iron deficiency like transferrin saturation index.
The authors surmised that serum hepcidin concentration identified a subset of anaemic, critically ill patients in whom IV iron therapy was effective in reducing RBC transfusion requirement.
What I understood?
Predicting response to iron therapy is always difficult and unpredictable. Using the Hepcidin level, if response to therapy can be predicted, lot of blood transfusions can be safely avoided
Where this study fails?
No septic patients included
No correlation with perfusion markers.
Sunday, September 23, 2018
Is the last bastion of blood transfusion falling?
Good Morning
Today, we report the findings of a meta analysis evaluating the effect of blood transfusion on long term and short term outcomes amongst patients with STEMI.
Red blood cell transfusion in patients with ST-elevation myocardial infarction—a meta-analysis of more than 21,000 patients.
Mincu R I et al
Neth Heart J (2018) 26:454–460
The indications for transfusions in critically ill patients are narrowing down. More and more evidence seems to be pointing towards harm with liberal transfusion triggers. One of the subsets of patients where liberalism has been accepted is STEMI. It is hypothesized that lower Hb levels potentiate the genesis of ischemia and may be detrimental to the outcomes among patients with STEMI. Well designed RCTs evaluating transfusion triggers in STEMI are also understandably lacking.
Mincu et al carried out a meta analysis "to determine the impact of RBT on short-term and long term outcomes in patients with STEMI, in order to address the gaps in knowledge in the management of these patients.
In the absence of RCTs, 5 well designed high quality cohort studies were chosen for the meta analysis. More than 21000 patients were identified. 984 patients received transfusion. Patients who received transfusion had higher prevalence of DM and HTN. Previous MI, CABG and stroke rates were comparable between the two cohorts. Premorbid conditions seem to be higher in the cohort which received transfusions. The mean minimum Hb in the transfusion group was 8.5gm/dl. Patients who received transfusion had a higher in hospital mortality. The risk of long term mortality was also higher amongst patients with STEMI who received blood transfusions. More importantly, reinfarction rates were higher in those who received blood transfusions. More patients in the STEMI with transfusions progressed to heart failure.
What I understood:
1. Comorbidities associated with lower Hb are often the triggers for transfusion.
2. Patients with STEMI with lower Hb levels do worse that those with higher Hb
3. Correcting the Hb with Blood transfusions does not confer any benefit.
Good Morning
Today, we report the findings of a meta analysis evaluating the effect of blood transfusion on long term and short term outcomes amongst patients with STEMI.
Red blood cell transfusion in patients with ST-elevation myocardial infarction—a meta-analysis of more than 21,000 patients.
Mincu R I et al
Neth Heart J (2018) 26:454–460
The indications for transfusions in critically ill patients are narrowing down. More and more evidence seems to be pointing towards harm with liberal transfusion triggers. One of the subsets of patients where liberalism has been accepted is STEMI. It is hypothesized that lower Hb levels potentiate the genesis of ischemia and may be detrimental to the outcomes among patients with STEMI. Well designed RCTs evaluating transfusion triggers in STEMI are also understandably lacking.
Mincu et al carried out a meta analysis "to determine the impact of RBT on short-term and long term outcomes in patients with STEMI, in order to address the gaps in knowledge in the management of these patients.
In the absence of RCTs, 5 well designed high quality cohort studies were chosen for the meta analysis. More than 21000 patients were identified. 984 patients received transfusion. Patients who received transfusion had higher prevalence of DM and HTN. Previous MI, CABG and stroke rates were comparable between the two cohorts. Premorbid conditions seem to be higher in the cohort which received transfusions. The mean minimum Hb in the transfusion group was 8.5gm/dl. Patients who received transfusion had a higher in hospital mortality. The risk of long term mortality was also higher amongst patients with STEMI who received blood transfusions. More importantly, reinfarction rates were higher in those who received blood transfusions. More patients in the STEMI with transfusions progressed to heart failure.
What I understood:
1. Comorbidities associated with lower Hb are often the triggers for transfusion.
2. Patients with STEMI with lower Hb levels do worse that those with higher Hb
3. Correcting the Hb with Blood transfusions does not confer any benefit.
Sunday, September 16, 2018
Some interesting articles
Muñoz. Primary decompressive craniectomy in neurocritical patients. a meta-analysis of randomized controlled trials, cohort and case-control studies. J Emerg Crit Care Med 2018;2:73
Lilly. Comparative Effectiveness of Proton Pump Inhibitors vs Histamine Type 2 Receptor Blockers for Preventing Clinically Important Gastrointestinal Bleeding During Intensive Care. A Population-Based Study. Chest 2018;154(3):557–566
Rahul. Effects of positive end-expiratory pressure strategy in supine and prone position on lung and chest wall mechanics in acute respiratory distress syndrome. Ann Intensive Care 2018;8(1):86Ann Intensive Care 2018;8(1):86
Kaliyaperumal. Pharmacogenomics of drug-induced liver injury (DILI): Molecular biology to clinical applications. J Hepatology 2018;69(4):948-957
Muñoz. Primary decompressive craniectomy in neurocritical patients. a meta-analysis of randomized controlled trials, cohort and case-control studies. J Emerg Crit Care Med 2018;2:73
Lilly. Comparative Effectiveness of Proton Pump Inhibitors vs Histamine Type 2 Receptor Blockers for Preventing Clinically Important Gastrointestinal Bleeding During Intensive Care. A Population-Based Study. Chest 2018;154(3):557–566
Rahul. Effects of positive end-expiratory pressure strategy in supine and prone position on lung and chest wall mechanics in acute respiratory distress syndrome. Ann Intensive Care 2018;8(1):86Ann Intensive Care 2018;8(1):86
Kaliyaperumal. Pharmacogenomics of drug-induced liver injury (DILI): Molecular biology to clinical applications. J Hepatology 2018;69(4):948-957
Good Morning
This weeks review is related to the use of recruitment maneuvers for moderate to severe ARDS guided by echo cardiography.
Moderate and Severe Acute Respiratory Distress Syndrome: Hemodynamic and Cardiac Effects of an Open Lung Strategy With Recruitment Maneuver Analyzed Using Echocardiography.
Mercado et al
Crit Care Med 2018; 46:1608–1616
Moderate to severe ARDS is still a therapeutic challenge. Achieving acceptable goals of oxygenation among these patients is offset quite often by the fear of hemodynamic compromise. Recruitment maneuvers have not found strong evidence based backing. However, there might be yet some subset of patients who need and benefit from recruitment maneuvers. Identifying the optimum PEEP also remains a tricky proposition.
Mercado et al in a prospective observational study attempted to evaluate a decremental PEEP strategy combined with echocardiographic assessment of LV and RV function and strain. Their hypothesis was based on a premise that recruitment maneuvers and high PEEP applied during the expiratory limb of the PV curve is safer for both the lung and the heart.
They identified patients with moderate to severe ARDS as per the Berlin definition. They ensured euvolemia by using the PLR maneuver and correcting it prior to application of the recruitment maneuver. All patients had invasive arterial pressure as well as CVP monitoring. They applied the principle of coronary perfusion pressure as defined by MAP - CVP. RV and LV strain were also measured along with End Diastolic Volumes and TAPSE/MAPSE.
All the study patients were paralysed. Recruitment was started by applying a PEEP of 25 cm H2O with a driving pressure of 15 cm H2O. PEEP was then incrementally increased by 5 cm H2O every 2 minutes with a constant driving pressure until a PEEP of 40 cm H2O was reached. Once this level of PEEP was reached, PEEP was reset to 25-15 and decrement strategy started. Decrement was achieved at 5 cm H20 of PEEP every 4 minutes. Oxygen saturation and compliance were measured to identify the point of termination of decreasing PEEP. A fall in SpO2 by > 2% or compliance by > 2 ml /cm H2O were the triggers to stop PEEP. From this point recruitment as described above was repeated again and PEEP was reduced to a level higher than previous start level.
Hemodynamics were assessed by MAP, CVP, Coronary Perfusion Pressure and Echocardiography both at peak recruitment as well as at optimum PEEP.
The effects of recruitment maneuvers were dramatic. The Systolic pressure fell by 17% , DBP by 14%, MAP by 15 % SV by 19% and CO by 20% between optimum and peak PEEP levels. The CVP rose significantly to cause a fall of Coronary Perfusion Pressure by 37%. These changes were transient and reverted to baseline within a hour of downsizing the PEEP. LV strain and RV strain were also noted.
Non responders were identified by several parameters. Non responders had higher RVEDA/LVEDA ratios. All hemodynamic parameters had far greater decrements in non responders than amongst responders.
What the authors say:
This study demonstrates that in patients with moderate to severe ARDS, a slow stepwise RM is associated with oxygenation improvement and transient and reversible right and left cardiac dysfunction. Furthermore, setting a higher PEEP after this RM dramatically improved both oxygenation and lung function without any deterioration in either LV or RV function.
An open lung strategy achieved by a slow stepwise RM appears to be beneficial for the lung while not resulting in negative effects on the heart.
My views:
1. This study shows the value of hemodynamic monitoring during recruitment.
2. Recruitment maneuvers are not hemodynamically neutral
3. Hemodynamic assessment could identify those who may not benefit from RM
4. This is a small study of 20 patients each. May not find favor as EBM, but has a sound physiological basis
This weeks review is related to the use of recruitment maneuvers for moderate to severe ARDS guided by echo cardiography.
Moderate and Severe Acute Respiratory Distress Syndrome: Hemodynamic and Cardiac Effects of an Open Lung Strategy With Recruitment Maneuver Analyzed Using Echocardiography.
Mercado et al
Crit Care Med 2018; 46:1608–1616
Moderate to severe ARDS is still a therapeutic challenge. Achieving acceptable goals of oxygenation among these patients is offset quite often by the fear of hemodynamic compromise. Recruitment maneuvers have not found strong evidence based backing. However, there might be yet some subset of patients who need and benefit from recruitment maneuvers. Identifying the optimum PEEP also remains a tricky proposition.
Mercado et al in a prospective observational study attempted to evaluate a decremental PEEP strategy combined with echocardiographic assessment of LV and RV function and strain. Their hypothesis was based on a premise that recruitment maneuvers and high PEEP applied during the expiratory limb of the PV curve is safer for both the lung and the heart.
They identified patients with moderate to severe ARDS as per the Berlin definition. They ensured euvolemia by using the PLR maneuver and correcting it prior to application of the recruitment maneuver. All patients had invasive arterial pressure as well as CVP monitoring. They applied the principle of coronary perfusion pressure as defined by MAP - CVP. RV and LV strain were also measured along with End Diastolic Volumes and TAPSE/MAPSE.
All the study patients were paralysed. Recruitment was started by applying a PEEP of 25 cm H2O with a driving pressure of 15 cm H2O. PEEP was then incrementally increased by 5 cm H2O every 2 minutes with a constant driving pressure until a PEEP of 40 cm H2O was reached. Once this level of PEEP was reached, PEEP was reset to 25-15 and decrement strategy started. Decrement was achieved at 5 cm H20 of PEEP every 4 minutes. Oxygen saturation and compliance were measured to identify the point of termination of decreasing PEEP. A fall in SpO2 by > 2% or compliance by > 2 ml /cm H2O were the triggers to stop PEEP. From this point recruitment as described above was repeated again and PEEP was reduced to a level higher than previous start level.
Hemodynamics were assessed by MAP, CVP, Coronary Perfusion Pressure and Echocardiography both at peak recruitment as well as at optimum PEEP.
The effects of recruitment maneuvers were dramatic. The Systolic pressure fell by 17% , DBP by 14%, MAP by 15 % SV by 19% and CO by 20% between optimum and peak PEEP levels. The CVP rose significantly to cause a fall of Coronary Perfusion Pressure by 37%. These changes were transient and reverted to baseline within a hour of downsizing the PEEP. LV strain and RV strain were also noted.
Non responders were identified by several parameters. Non responders had higher RVEDA/LVEDA ratios. All hemodynamic parameters had far greater decrements in non responders than amongst responders.
What the authors say:
This study demonstrates that in patients with moderate to severe ARDS, a slow stepwise RM is associated with oxygenation improvement and transient and reversible right and left cardiac dysfunction. Furthermore, setting a higher PEEP after this RM dramatically improved both oxygenation and lung function without any deterioration in either LV or RV function.
An open lung strategy achieved by a slow stepwise RM appears to be beneficial for the lung while not resulting in negative effects on the heart.
My views:
1. This study shows the value of hemodynamic monitoring during recruitment.
2. Recruitment maneuvers are not hemodynamically neutral
3. Hemodynamic assessment could identify those who may not benefit from RM
4. This is a small study of 20 patients each. May not find favor as EBM, but has a sound physiological basis
Subscribe to:
Comments (Atom)