Matej Podbregar

Changes in muscle tissue oxygenation during stagnant ischemia in septic patients

ObjectiveTo determine changes in the rate of thenar muscles tissue deoxygenation during stagnant ischemia in patients with severe sepsis and septic shock.Design and settingProspective observational study in the medical ICU of a general hospital.Patients and participantsConsecutive patients admitted to ICU with septic shock (n=6), severe sepsis (n=6), localized infection (n=3), and healthy volunteers (n=15).InterventionsUpper limb ischemia was induced by rapid automatic pneumatic cuff inflation around upper arm.Measurements and resultsThenar muscle tissue oxygen saturation (StO2) was measured continuously by near-infrared spectroscopy before and during upper limb ischemia. StO2 before intervention was comparable in patients with septic shock, severe sepsis, or localized infection and healthy volunteers (89 [65, 92]% vs. 82 [72, 91]% vs. 87 [85, 92]% vs. 83 [79, 93]%, respectively; p>0.1). The rate of StO2 decrease during stagnant ischemia after initial hemodynamic stabilization was slower in septic shock patients than in those with severe sepsis or localized infection and in controls (–7.0 [–3.6, –11.0] %/min vs. –10.4 [–7.8, –13.3] %/min vs. –19.5 [–12.3, –23.3] vs. –37.4 [–27.3, –56.2] %/min, respectively; p=0.041). At ICU discharge the rate of StO2 decrease did not differ between the septic shock, severe sepsis, and localized infection groups (–17.0 [–9.3, –28.9] %/min vs. –19.9 [–13.3, –23.6] %/min vs. –23.1 [–20.7, –26.2] %/min, respectively), but remained slower than in controls (p<0.01). The rate of StO2 decrease was correlated with Sequential Organ Failure Assessment (SOFA) score (r=0.739, p<0.001).ConclusionsAfter hemodynamic stabilization thenar muscle tissue oxygen saturation during stagnant ischemia decreases slower in septic shock patients than in patients with severe sepsis or localized infection and in healthy volunteers. During ICU stay and improvement of sepsis the muscle tissue deoxygenation rate increases in survivors of both septic shock and severe sepsis and was correlated with SOFA score.

Differences between bisoprolol and carvedilol in patients with chronic heart failure and chronic obstructive pulmonary disease: a randomized trial

BACKGROUND Chronic obstructive pulmonary disease (COPD) frequently coexists in patients with chronic heart failure (CHF) and is a key factor for beta blocker underprescription and underdosing. This study compared effects of bisoprolol and carvedilol in patients with both conditions. METHODS This was a randomized open-label study, of bisoprolol and carvedilol during initiation and uptitration to target or maximal tolerated dose. Pulmonary function testing, 12-lead electrocardiogram, and N-terminal pro brain natriuretic peptide were measured at baseline and follow-up. RESULTS We randomized 63 elderly patients (73 ± 9 years, 81% men, left ventricular ejection fraction 33 ± 7%) with mild to moderate CHF (54% New York Heart Assocation class II) and moderate to severe COPD (76% Global initiative for chronic Obstructive Lung Disease stage 2). Target dose was tolerated by 31 (49%) patients and 19 (30%) patients experienced adverse events during follow-up (19% bisoprolol, 42% carvedilol, p = 0.045). Study medication had to be withdrawn in 8 (13%) patients (bisoprolol: 2 due to hypotension, 1 due to bradycardia; carvedilol: 2 due to hypotension and 1 due to wheezing, dyspnoea, and oedema, respectively). Forced expiratory volume in 1(st) second significantly increased in bisoprolol (1561 ± 414 ml to 1698 ± 519 ml, p = 0.046) but not carvedilol (1704 ± 484 to 1734 ± 548, p = 0.44) group. Both agents reduced heart rate (bisoprolol: 75 ± 14 to 68 ± 10, p = 0.007; carvedilol 78 ± 14 to 72 ± 12, p = 0.016) and had no effect on N-terminal pro brain natriuretic peptide. CONCLUSIONS Beta blockers frequently caused adverse events, and thus 49% of patients could tolerate the target dose. Bisoprolol induced demonstrable improvement in pulmonary function and caused less adverse events.

Efficacy and impact of monophasic versus biphasic countershocks for transthoracic cardioversion of persistent atrial fibrillation.

This report compares the cumulative efficacy of cardioversion and skeletal muscle injury after either damped sine wave monophasic or truncated exponential biphasic transthoracic cardioversion of persistent atrial fibrillation. The trial sought to refute the null hypothesis of therapeutic equivalence between monophasic and biphasic waveforms. Results of the study reveal similar cumulative efficacy of waveforms and greater levels of skeletal muscle damage when patients are younger and male, and when monophasic waveforms are used.

Effect of selective and non-selective β-blockers on body weight, insulin resistance and leptin concentration in chronic heart failure

BackgroundChronic heart failure (CHF) is characterized by increased insulin resistance and hyperleptinaemia. We aimed to study effects of selective and non-selective β-blockers on body weight, insulin resistance, plasma concentrations of leptin and resistin in patients with CHF.MethodsTwenty-six non-cachectic β-blocker-naive patients with CHF were randomized and treated with either carvedilol or bisoprolol. Body weight, plasma concentrations of leptin, resistin, fasting glucose and insulin were measured at baseline and after 6 months of therapy. Insulin resistance was estimated by homeostasis model assessment- estimated insulin resistance (HOMA-IR).ResultsBody weight increased significantly in the carvedilol group (mean change + 2.30 kg, p = 0.023) while it did not change in the bisoprolol group (mean change –0.30 kg, p = 0.623) (ns between groups). Plasma leptin concentration increased only in the carvedilol group (mean change + 4.20 ng/ml, p = 0.019) (ns between groups). Fasting glucose and resistin remained unchanged in both groups. After 6 months, mean plasma insulin concentration changed significantly differently (p = 0.015) in the bisoprolol (mean change +3.1 µU/ml) compared to the carvedilol group (mean change –6.3 µU/ml) and HOMA-IR was consequently higher in the bisoprolol compared to the carvedilol group (5.2 ± 4.2 vs 2.8 ± 1.6, p = 0.046).ConclusionThis study found different metabolic effects of carvedilol and bisoprolol in non-cachectic patients with CHF. With unchanged fasting plasma glucose concentration after 6 months of treatment, carvedilol significantly decreased plasma insulin concentration and insulin resistance compared to bisoprolol.

Analgesic treatment and predictors of satisfaction with analgesia in patients with acute undifferentiated abdominal pain

The objectives of this prospective, observational cohort study were to examine current practice of analgesia in adults with acute abdominal pain presenting to emergency department (ED), to assess patient—physician agreement on pain severity, and to measure patients’ satisfaction with pain management.

Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.

SummaryBackgroundPatients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism.Patients and methodsTen consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter.ResultsAt 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31±10 vs. 49±12%, p<0.0001; 86±12 vs. 105±17 mmHg, p<0.01; 1.5±0.4 vs. 1.9±0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonaryartery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29±10 vs. 21±12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=−0.855, p<0.001).ConclusionIn obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.

Use of Near Infrared Spectroscopy to Asses Remote Ischemic Preconditioning in Skeletal Muscle

Remote ischemic preconditioning (IPC) is a procedure during which brief periods of ischemia protect distant organ from ischemia-reperfusion injury. Appling IPC on an upper arm, this phenomenon has been demonstrated in several studies. Skeletal muscle tissue oxygenation at rest (StO2) and StO2 deoxygenation rate during vascular occlusion can be measured using near infrared spectroscopy (NIRS). We aimed to investigate the effects of remote upper arm IPC on StO2 and flow-mediated dilatation (FMD) in healthy male volunteers. In a randomized controlled crossover trial, resting StO2, StO2 deoxygenation rate, and FMD were measured on testing arm at baseline and after 60 minutes. After basal measurements IPC protocol on a contralateral arm was performed. StO2 deoxygenation rate was significantly lower after remote, the IPC cycles in comparison to deoxygenation rate at baseline ( versus %, ). Comparison of deoxygenation rates showed a significant difference between the IPC and the control protocol (, ). No differences were observed in FMD before and after remote IPC and in the control protocol. In healthy young adults, remote IPC reduces StO2 deoxygenation rate but has no significant impact on FMD. NIRS technique offers a novel approach to asses skeletal muscle adaptation in response to remote ischemic stimuli.

How I use skeletal muscle Near Infrared Spectroscopy to non-invasively assess hemodynamic status of the critically ill

The major goal of hemodynamic treatment is to reach adequate flow. Near infrared spectroscopy (NIRS) allows non-invasive assessment of skeletal muscle tissue oxygenation during rest and also during vascular occlusion test (VOT). VOT allows estimation of tissue oxygen extraction capability, which could be preserved (i.e. hypovolemic, obstructive and cardiogenic shock) or inappropriate (i.e. sepsis/ septic shock). By using ultrasound to estimate cardiac output, arterial hemoglobin oxygen saturation, skeletal muscle NIRS, arterial lactate and hemoglobin, therapeutic goals in critically ill patients with preserved oxygen extraction capability can easily be targeted. Current controversies of NIRS technology and approach to patients with impaired oxygen extraction are discussed as well.

Selective stimulation of the vagus nerve in a man

The term ‘Vagus Nerve Stimulation’ (VNS) generally refers to several different techniques used to non-selectively stimulate the vagus nerve. The aim of our study was to study feasibility and safety of selective VNS. We present the results of modeling, design, and experimental testing of a multi-electrode spiral nerve cuff (cuff) to determine to what extent a cuff could be used to purposely temporarily affect the function of the heart in a man under precisely controlled conditions in selective stimulation of different types of fibers within particular compartments of the vagal nerves in a man.

QUALITY OF LIFE IN PATIENTS AFTER MASSIVE PULMONARY EMBOLISM

Background. Pulmonary embolism is a disease, which has a 30% mortality if untreated, while an early diagnosis and treatment lowers it to 2–8%. Health related quality of life (HRQL) of patients who survived massive pulmonary embolism is unknown in published literature. In our research we tried to apply experience of foreign experts in estimation of quality of life in some other diseases to the field of massive pulmonary embolism. Patients and methods. Eighteen patients with shock or hypotension due to massive pulmonary embolism, treated with thrombolysis, between July 1993 and November 2000, were prospectively included in the study. Control group included 18 gender and age matched persons. There were no significant differences regarding demographic data between the groups. The HRQL and aerobic capacity of patients and control group were tested with short questions and questionnaires (Veterans brief, self administered questionnaire (VSAQ), EuroQuality questionnaire (EQ), Living with heart failure questionnaire (LlhHF). With LlhHF physical (F-LlhHF) and emotional (E-LlhHF) HRQL was assessed at hospitalization and 12 months later. Results. One year after massive pulmonary embolism aerobic capacity (–9.5%, p < 0.017) and HRQL (EQ (–34.5%), F-LlhHF (–85.4%), E-LlhHF (–48.7%)) decreased in massive pulmonary embolism group compared to aerobic capacity 6 months before massive pulmonary embolism and HRQL. Heart rate before thrombolysis correlated with aerobic capacity (r = 0.627, p < 0.01), EQ (r = 0.479, p < 0.01) and F-LlhHF (r = 0.479, p = 0.04) 1 year after massive pulmonary embolism. Total pulmonary resistance at 12 hours after start of treatment correlated with aerobic capacity at 1 year (r = 0.354, p < 0.01). With short question (»Did you need any help in everyday activities in last 2 weeks?«) we successfully separated patients with decreased HRQL in EQ (74.3 ± 20.8 vs. 24.5 ± 20.7, p < 0.001) and F-LlhHF (21.7 ± 6.7 vs. 32.8 ± 4.3, p < 0.01), but we could not identify the patients with deminished aerobic capacity. Conclusions. Aerobic capacity, emotional and physical quality of life is decreased one year after massive pulmonary embolism in patients treated with thrombolysis. A linear correlation between decrease in aerobic capacity and total pulmonary resistance after 12 hours of treatment was present.