Liberation from mechanical ventilation: targeted weaning versus daily weaning trials

Critical-care clinicians must carefully weigh the benefits of rapid liberation from mechanical ventilation against the risks of premature trials of spontaneous breathing and extubation. Our aim of work was to study the capability of respiratory system mechanics as weaning parameters. In 30 patients who have been mechanically ventilated due to pulmonary causes of respiratory failure, we divided patients into 2 groups: [Group 1] in which weaning was postponed until certain values of lung mechanics have been reached [targeted weaning], and [Group 2] in which patients undergone daily weaning trials once the general criteria of weaning have been fulfilled irrespective of their lung mechanics values. Targeted weaning threshold values were as follows: static compliance >33ml/cmH[2]O dynamic compliance >22ml/cmH[2]O, resistance 0.05]. Targeted weaning group has showed less number of weaning trials and fewer incidences of re-intubation events with no increase in mechanical ventilation time or complications. We concluded that respiratory mechanics were modest weaning predictors. But on the other hand, targeted weaning by respiratory mechanics constituted a much more economic and resource preserving protocol of weaning

Effect of haemofiltration in prevention of contrast induced nephropathy and on acid/base status in predialysis chronic kidney disease patients undergoing cardiac catheterization

High risk renal failure patients have increased risk for contrast nephropathy during coronary angiography despite the use of conventional prophylaxis with intravenous hydration and acetylcysteine. The aim of the study was assess the role of haemo filtration versus conventional prophylaxis in preservation of kidney function and prevention of contrast nephropathy in chronic kidney disease patients undergoing cardiac catheterisation. There was a highly significant reduction in BUN, creatinine, serum uric acid [p<0.001] in haemofiltration group in comparison with baseline and control group till day 4 that was not significant after one week. There was a significantly improving rise in pH and serum HCO[3] level in haemofiltration in haemofiltration group till 24 hours post contrast injection [p<0.001]. Haemofiltration can provide adequate pres ervation of kidney function in high risk renal patients under going cardiac catheterisation. It also achieved proper adjustment of acid/base status in such patients

Biological significance of stem cells [CD34 +] and vascular endothelial growth factor [VEGF] in the peripheral blood of patients with acute myocardial infarction

Reports on stem cell transplantation-an innovative approach to repair damaged myocardium following acute myocardial infarction [AMI]-have raised the question of a possible spontaneous mobilization of corresponding stem cells from the bone marrow of ischemic patients. Exposed to vascular endothelial-derived growth factor [VEGF], such cells would differentiate into myocardial cells within the infarcting myocardium, thus hopefully initiating the reparative process. The present work assessed the prevalence of marrow derived stem cells expressed in term of percent of CD34 + cells in the peripheral blood of patients sustaining AMI, as well as the serum level of VEGF needed for their differentiation into cardiac myocytes. We studied 21 male patients with AMI [mean age 52.5 +/- 8.9 years]. Myocardial infarction was anterior in 10 and inferior in 11 patients. Eleven healthy males [mean age 53.9 +/- 9.4 years] served as controls. Following admission, all patients and controls were subjected to clinical examination including 12-lead ECG with routine laboratory evaluation comprising total and differential CBC, hepatic and renal functions, as well as relevant cardiac serum enzymes with the latter repeatedly measured every 8 hours to detect the highest peak of CK. Specific laboratory measurements included flowcytometric analysis of peripheral blood mononuclear cells to detect CD34 + population and serum VEGF level by ETA on admission, 3 day, and prior to discharge. Comparing the mean percent values of CD34 + cells on admission [7.02 +/- 3.08], ischemic patients exhibited insignificantly higher levels of CD34 on the 3rd day [8.57 +/- 3.5] as well as on discharge [8.45 +/- 3.5]. The above mentioned values were also insignificantly different from samples withdrawn from control subjects [8.84 +/- 3.4]. However, CD34 cell population was positively correlated with the extent of myocardial damage expressed in terms of peak CK. Thus with an arbitrary limit of >/= 30% rise in CD34, two patients subgroups could be stratified, with 12 patients having >/= 30% rise in CD 34, exhibiting a peak CK of 2498.6 IU/L, and 9 patients showing < 30% rise in CD34 presenting a peak CK of 1312.9 IU/L. However this relationship was not of statistical significance. Serum VEGF surprisingly showed a trend towards decrease rather than increase when compared to control subjects [1.23 +/- 0.99 versus 2.79 +/- 1.67 respectively, p = 0.001], with the decline maintained over the 3rd day and prior to discharge in most patients, raising the issue of increased consumption during the process of stem cell differentiation. Acute myocardial infarction apparently initiated a series of molecular and biological events whereby continued mobilization of bone marrow stem cells [expressed by continuing rise of CD34 marker] was triggered. Subsequent homing into myocardium lead to continuous consumption of VEGF needed for their differentiation into cardiac myocytes. This phenomenon could be part of a spontaneous reparative process potentially raising hopes of therapeutic applications

Efficacy of recombinant human erythropoietin in critically ill anaemic septic patients

To investigate the erythropoietic response to high dose of a weekly dosing schedule of recombinant human erythropoietin [rHuEPO] in critically ill anaemic septic patients, and to determine whether the administration of rHuEPO would reduce the number of red blood cell [RBC] transfusions required and whether would affect clinical course and final outcome or not. A prospective, randomized, controlled single center study. Critical Care Department [medical/surgical ICU], Cairo University Hospital. A total of 60 patients who were admitted to the intensive care unit [ICU] and met the eligibility criteria were enrolled into the study [30 into the rHuEPO group, 30 into the control group]. Patients were randomized to receive either rHuEPO or not. The study drug [40.000 units of rHuEPO] was administrated by subcutaneous injection beginning on ICU day 2 and continued once weekly for a minimum of 2 doses or until ICU discharge [for patients with ICU length of stay >2 weeks] up to a total of 4 doses. CBC, reticulocytic count, iron variables, APACHE II, SOFA scores were measured at baseline and subsequently thereafter every 3rd day until ICU discharge or death or up to a total of 28 days. The EPO treated group showed significant increases in reticulocytic count compared with baseline [P<0.001] as well as with the control group [P<0.006]. The EPO-treated group exhibited also significant increases in Hb concentration compared with baseline [P<0.001] as well as with the control group [P<0.03]. All patients in the control group received RBC transfusion [100%] while only [83.33%] of the patients who received rHuEPO were transfused. Concerning the in hospital clinical course, the EPO treated group showed significant decreases in their APACHE II score during the study period compared with baseline [P<0.001] as well as with the control group [P<0.05], the EPO treated group showed also no significant difference in their SOFA score during the study period compared with baseline [P=0.923], however, the control group exhibited continous and significant increase in their SOFA score throughout the study period compared with baseline [P<0.003]. There was no significant difference in the final outcome [i.e. recovery, mortality or morbidity] [P:0.337, P: 0.286 respectively]. The administration of rHuEPO to critically ill anaemic septic patients is effective in raising their reticulocytic counts, Hb concentrations and in reducing the total number of units of RBCs they require. In addition there was a trend toward better inhospital clinical course, increased recovery and decreased mortality in rHuEPO group

Interleukin-6 [IL-6] in unstable angina pectoris. Prevalence and relation to extent of coronary artery disease

Increasing evidence for inflammation in acute ischemic syndromes has been recently suggested by the finding of elevated serum level of inflammatory markers including Interleukin-6 [IL-6].This seemingly attractive hypothesis needs further elucidation. This study is intended to assess the levels of IL-6 in unstable angina and to evaluate whether this serum level correlates with angiographic extent of coronary arterial disease. To achieve this goal we studied 80 ischemic patients and 20 healthy subjects with angiographically normal coronary arteries [10 F, 10 M, Mean age: 44.3 +/- 1.43yr] served as controls. Ischemic patients were divided into 2 groups, stable angina group [39 patients, 14 F, 25 M, mean age 47.7 +/- 1.31yr] and unstable angina group [41 patients, 7 F, 34 M mean age 48.9 +/- 1.012yr]. Following clinical evaluation including 12- lead ECG, patients and controls had routine laboratory investigations, liver, kidney functions and IL-6 was measured by automated chemiluminescence. Coronary artery disease was confirmed by diagnostic coronary angiography. Extent of coronary artery disease was expressed in terms of number of vessels affected according to 1-3 vessel score. Compared to control subjects and stable angina group, those with unstable angina had a significantly higher level of IL-6 [P< 0.001, P: 0.006 respectively]. In stable angina group, 26 cases had normal value [9.7 <30 pg/mL], 6 cases were moderate [>30 < 60 pg/mL] and 5 cases were severe [260 pg/mL]. In unstable angina group IL-6 evaluation revealed that 16 cases were normal [<9.7 pg/mL], 5 cases were mild [>9.7 <30 pg/mL], 2 cases were moderate [>30 <60 pg/ mL] and 18 cases were severe [>60 pg/mL], while all control subjects had normal IL-6 level. According to angiographic 1- to 3 - vessel score, IL-6 level was significantly higher in those with multivessel disease [P< 0.001]

Conclusion: Among patients with stable and unstable angina undergoing coronary angiography, the higher levels of IL-6 were significantly associated with unstable angina and correlated with the extent of coronary artery disease. This finding points to the potential role played by inflammation in the pathophysiology of unstable angina

effects of different levels of auto-PEEP on hemodynamics in mechanically ventilated patients, correlation with lung mechanics and gas exchange in different ventilator settings

The goal of this study was to detect auto-PEEP in mechanically ventilated patients and monitor how its different levels may affect the patients hemodynamics, lung mechanics and gas exchange and trial of estimating an optimal PEEP level. Another goal was to monitor how the addition of external PEEP may affect the patient hemodynamics, lung mechanics and gas exchange and trial of estimating an optimal PEEP level. This study included 18 mechanically ventilated patients who were classified into three groups: COPD group [10 patients], restrictive group [4 patients] and normal group [4 patients]. Besides the routine clinical examination, ECG, chest X-ray, laboratory investigation and ABG, each individual patient was subjected to serial monitoring of hemodynamic parameters [SV, PCWP, LVSW, RVSW, PVR], lung mechanics parameters [auto-PEEP, external PEEP, total PEEP, P pressure, P mean, P total, Raw, C stat]. This is done for base line readings and after every change in ventilatory settings according to the study on different levels of auto-PEEP and on different levels of external PEEP. The results showed that auto-PEEP was detected in 13 out of 18 patients included in the study [72%] with mean of 6.8 cm H2O SD 5. On application of external PEEP, auto-PEEP had a significantly negative correlation with external PEEP in all groups