Feasibility of the optimal cerebral perfusion pressure value identification without a delay that is too long

Optimal cerebral perfusion pressure (CPPopt)-targeted treatment of traumatic brain injury (TBI) patients requires 2-8 h multi-modal monitoring data accumulation to identify CPPopt value for individual patient. Minimizing the time required for monitoring data accumulation is needed to improve the efficacy of CPPopt-targeted therapy. A retrospective analysis of multimodal physiological monitoring data from 87 severe TBI patients was performed by separately representing cerebrovascular autoregulation (CA) indices in relation to CPP, arterial blood pressure (ABP), and intracranial pressure (ICP) to improve the existing CPPopt identification algorithms. Machine learning (ML)-based algorithms were developed for automatic identification of informative data segments that were used for reliable CPPopt, ABPopt, ICPopt and the lower/upper limits of CA (LLCA/ULCA) identification. The reference datasets of the informative data segments and, artifact-distorted segments, and the datasets of different clinical situations were used for training the ML-based algorithms, allowing us to choose the appropriate individualized CPP-, ABP- or ICP-guided management for 79% of the full monitoring time for the studied population. The developed ML-based algorithms allow us to recognize informative physiological ABP/ICP variations within 24 min intervals with an accuracy up to 79% (compared to the initial accuracy of 74%) and use these segments for timely optimal value identification or CA limits determination in CPP, ABP or ICP data. Prospective clinical studies are needed to prove the efficiency of the developed algorithms.

Immediate aspiration of the drug infused via central venous catheter through the distally positioned central venous dialysis catheter: An experimental study

OBJECTIVES

The aim of this study was to construct an experimental model replicating blood flow within human superior vena cava and to determine the degree of the immediate aspiration of the drug introduced via central venous catheter through the distally positioned dialysis catheter.

METHODS

A model replicating superior vena cava was built, catheters were inserted into the model, placing the orifice of the central venous catheter in positions regarding the orifice of the arterial lumen in central venous dialysis catheter (from +2 to -8 cm). Methylene blue was used as a tracer, and the concentration was determined by ultraviolet-visible spectroscopy. Four different sets of samples were generated according to infusion and aspiration speeds: continuous-slow, continuous-fast, bolus-slow, and bolus-fast.

RESULTS

The concentration of the tracer was related to the distance between the catheter tips, representing a bimodal dependence. When the central venous catheter was placed distally to the central venous dialysis catheter, the aspiration of the tracer was minimal. When withdrawing the central venous catheter proximally, the aspiration of the tracer increased, reaching its peak at -4 cm with aspiration rates form 4.2% to 140.7%. Furthermore, the infusion speed of the tracer had more effect on the aspirated concentrations than the aspiration speed.

CONCLUSION

Findings of our experimental model suggest that concentration of aspired drug is effected by the distance between the central venous catheter and central venous dialysis catheter, being lowest when the drug is infused distally to central venous dialysis catheter. Furthermore, the concentration of the tracer is directly proportional to the infusion speed and far less effected by the aspiration rate of the drug.

Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient's Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring

Background and Objectives: The aim of this study was to explore the association between the cerebral autoregulation (CA) index, the pressure reactivity index (PRx), the patient’s clinical outcome, and the quality of arterial blood pressure (ABP(t)) and intracranial blood pressure (ICP(t)) signals by comparing two filtering methods to derive the PRx. Materials and Methods: Data from 60 traumatic brain injury (TBI) patients were collected. Moving averaging and FIR (Finite Impulse Response) filtering were performed on the ABP(t) and ICP(t) signals, and the PRx was estimated from both filtered datasets. Sensitivity, specificity, and receiver-operating characteristic (ROC) curves with the area under the curves (AUCs) were determined using patient outcomes as a reference. The outcome chosen for comparison among the two filtering methods were mortality and survival. Results: The FIR filtering approach, compared with clinical outcome, had a sensitivity of 70%, a specificity of 81%, and a level of significance p = 0.001 with an area under the curve (AUC) of 0.78. The moving average filtering method compared with the clinical outcome had a sensitivity of 58%, a specificity of 72%, and a level of significance p = 0.054, with an area under the curve (AUC) of 0.66. Conclusions: The FIR (optimal) filtering approach was found to be more sensitive for discriminating between two clinical outcomes, namely intact (survival) and impaired (death) cerebral autoregulation for TBI treatment decision making.

Resuscitation Following a Bupivacaine Injection for a Cervical Paravertebral Block

Background

Cardiac arrest related to nerve blockade using a local anaesthetic is a rare event. We report a case of bupivacaine severe cardiovascular toxicity following cervical paravertebral nerve block.

Case presentation

A 44-year-old female was admitted to Republican Vilnius University Hospital, with symptoms of sustained severe pain in her neck that radiated to both arms. Multiple cervical intervertebral hernias with spinal stenosis were confirmed by magnetic resonance imaging. Following infiltration of the subcutaneous tissue with a 0.5 % bupivacaine solution, an 18-gauge spinal needle was used to perform the paravertebral block at the C6 level. Bupivacaine was injected in incremental doses to a total of 10 mL. Rapid loss of consciousness and cardiovascular collapse suggested a neuraxial injection of bupivacaine. Long-lasting cardiopulmonary resuscitation, including chest compressions, defibrillation attempts for refractory ventricular fibrillation, medications, mechanical ventilation, and intravenous lipid emulsion infusion, was successful. No severe adverse outcomes other than acute kidney injury and chest pain related to prolonged chest compressions were documented.

Conclusions

This case report emphasizes the necessity of ensuring adequate safety precautions to avoid local anaesthetic systemic toxicity. Lipid emulsion preparations should be available in all hospital settings where local anaesthetics are used for regional anaesthesia or pain management.

Optimal head rotation angle for safe right internal jugular vein catheterization using out-of-plane approach: an ultrasonography study

AIM

The most common complication following internal jugular vein catheterization is the puncture of the common carotidartery. We aimed to find an optimal head rotation angle for safe vein catheter insertion while minimizing the risk of arterypuncture.

MATERIALS AND METHODS

Eighty-two patients admitted to the intensive care unit were included in the prospective study. Ultrasound examination of the neck vessels on the right side was performed in the neutral position and at a head rotation of 15°, 30°, 45° and 60° to the left. Internal jugular vein and common carotid artery puncture angle, overlapping angle of vein by artery and vein safe puncture angle were evaluated.

RESULTS

The internal jugular vein puncture angle increased with head rotation from the neutral position to 30° and 45° and was largest at 60° (p<0.001 for all). The overlapping angle increased significantly at 45° and 60° rotation compared with the neutral position (p<0.001 for all). The vein safe puncture angle was highest at 30° and significantly different from the neutral position and 60° (p=0.003 and p=0.013, respectively).

CONCLUSIONS

When performing right internal jugular vein catheterization without ultrasound guidance by using an out-of-plane technique, the head should be rotated at 30°, because the overlapping angle increases with further head rotation and can increase the risk of artery puncture.

Optimal Cerebral Perfusion Pressure: Targeted Treatment for Severe Traumatic Brain Injury

Identification of individual therapy targets is critical for traumatic brain injury (TBI) patients. Clinical outcomes depend on cerebrovascular autoregulation (CA) impairment. Here, we compare the effectiveness of optimal cerebral perfusion pressure (CPPopt)-targeted therapy in younger (<45 years of age) and elderly (≥45 years of age) TBI patients. Single-center multi-modal invasive arterial blood pressure(t), intracranial pressure (ICP)(t), cerebral perfusion pressure CPP(t), and CPPopt(t) monitoring (n = 81) was performed. ICM+ software was used for continuous CPPopt(t) status assessment by identification of pressure reactivity index (PRx). The most significant prognostic factors were age, Glasgow Coma Scale, serum glucose, and duration of longest CA ompairment event (LCAI) when PRx(t) >0.5 within 24 h after admission. The modeled accuracies for favorable and unfavorable outcome prediction were 86.5% and 90.9%, respectively. Age above 45 years and averaged ICP during all monitoring time above 21.3 mm Hg was associated with unfavorable outcome of an individual patient. Averaged CPP values close to CPPopt were associated with a better outcome in younger patients. Averaged ΔCPPopt <-5.0 mm Hg, averaged PRx >0.36, and LCAI >100 min were significantly associated with mortality for the younger patients. The critical values of averaged PRx >0.26 and LCAI >61 min were significantly associated with mortality for the elderly group. Autoregulation-guided treatment was important for individual TBI management, especially in younger patients. Further randomized multi-center studies are needed to prove final benefit.

Non-invasive Cerebrovascular Autoregulation Assessment Using the Volumetric Reactivity Index: Prospective Study

BACKGROUND

This prospective study of an innovative non-invasive ultrasonic cerebrovascular autoregulation (CA) monitoring method is based on real-time measurements of intracranial blood volume (IBV) reactions following changes in arterial blood pressure. In this study, we aimed to determine the clinical applicability of a non-invasive CA monitoring method by performing a prospective comparative clinical study of simultaneous invasive and non-invasive CA monitoring on intensive care patients.

METHODS

CA was monitored in 61 patients with severe traumatic brain injuries invasively by calculating the pressure reactivity index (PRx) and non-invasively by calculating the volumetric reactivity index (VRx) simultaneously. The PRx was calculated as a moving correlation coefficient between intracranial pressure and arterial blood pressure slow waves. The VRx was calculated as a moving correlation coefficient between arterial blood pressure and non-invasively-measured IBV slow waves.

RESULTS

A linear regression between VRx and PRx averaged per patients' monitoring session showed a significant correlation (r = 0.843, p < 0.001; 95% confidence interval 0.751 - 0.903). The standard deviation of the difference between VRx and PRx was 0.192; bias was - 0.065.

CONCLUSIONS

This prospective clinical study of the non-invasive ultrasonic volumetric reactivity index VRx monitoring, based on ultrasonic time-of-flight measurements of IBV dynamics, showed significant coincidence of non-invasive VRx index with invasive PRx index. The ultrasonic time-of-flight method reflects blood volume changes inside the acoustic path, which crosses both hemispheres of the brain. This method does not reflect locally and invasively-recorded intracranial pressure slow waves, but the autoregulatory reactions of both hemispheres of the brain. Therefore, VRx can be used as a non-invasive cerebrovascular autoregulation index in the same way as PRx and can also provide information about the CA status encompassing all intracranial hemodynamics.

Placenta percreta complicated by uterine rupture and thrombotic microangiopathy

Background

Uterine rupture at the site of a previous caesarean scar with abnormal placental penetration through the uterus wall with bladder invasion is a rare and serious pregnancy complication. Our aim was to report a case of uterine rupture with placenta percreta complicated by thrombotic microangiopathy.

Materials and methods

We did a literature review and analysed medical documentation retrospectively.

Results

A patient was admitted with complaints of lower abdominal pain at 21 weeks of gestation. Sonography of the caesarean scar increased suspicion of placental penetration. Anaemia, thrombocytopenia, coagulopathy, and acute kidney injury developed and led to the diagnosis of thrombotic microangiopathy. The termination of pregnancy was required due to severe deterioration in organ functions. The complete uterine rupture with placenta percreta invading the urinary bladder was confirmed, and total hysterectomy was performed to control life-threatening haemorrhage. The patient was treated by blood component transfusions, renal replacement therapy, and plasmapheresis. Good health was confirmed two months later by laboratory and instrumental tests.

Conclusions

It is a rare but very serious condition that increases morbidity of mother and foetus, therefore immediate diagnostics and treatment are required.

Evaluation of PRE-DELIRIC (PREdiction of DELIRium in ICu patients) delirium prediction model for the patients in the intensive care unit

Introduction

Delirium not only compromises patient care, but is also associated with poorer outcomes: increased duration of mechanical ventilation, higher mortality, and greater long-term cognitive dysfunction. The PRE-DELIRIC model is a tool used to calculate the risk of the development of delirium. The classification of the patients into groups by risk allows efficient initiation of preventive measures. The goal of this study was to validate the PRE-DELIRIC model using the CAM-ICU (The Confusion Assessment Method for the Intensive Care Unit) method for the diagnosis of delirium.

Materials and methods

Patients admitted to the University Hospital of Vilnius during February 2015 were enrolled. Every day, data were collected for APACHE-II and PRE-DELIRIC scores. Out of 167 patients, 38 (23%) were included and screened using the CAM-ICU method within 24 hours of admission to the ICU. We defined patients as having delirium when they had at least one positive CAM-ICU screening or haloperidol administration due to sedation. To validate the PRE-DELIRIC model, we calculated the area under receiver operating characteristic curve.

Results

The mean age of the patients was 69.2 ± 17.2 years, 19 (50%) were male, APACHE-II mean score 18.0 ± 7.4 points. Delirium was diagnosed in 22 (58%) of 38 patients. Data used for validation of the PRE-DELIRIC model resulted in an area under the curve of 0.713 (p < 0.05, 95% CI 0.539-0.887); sensitivity and specificity for the patients with 20% risk were, accordingly, 77.3% and 50%; 40% risk - 45.5% and 81.3%, 60% - 36.4%, and 87.5%.

Conclusions

The PRE-DELIRIC model predicted delirium in the patients within 24 hours of admission to the ICU. Preventive therapy could be efficiently targeted at high-risk patients if both of the methods are to be implemented.

Effects of ketamine on precipitated opiate withdrawal

OBJECTIVE

N-methyl-D-aspartate antagonists were shown to be effective in suppressing the symptoms of opiate withdrawal. Intravenous anesthetic, ketamine, is the most potent N-methyl-D-aspartate antagonist available in clinical practice. The present study was designed to evaluate the effects of subanesthetic ketamine infusion, as little human data are available on ketamine in precipitated opiate withdrawal.

MATERIALS AND METHODS

A total of 58 opiate-dependent patients were enrolled in a randomized, placebo-controlled, double-blind study. Patients underwent rapid opiate antagonist induction under general anesthesia. Prior to opiate antagonist induction patients were given either placebo (normal saline) or subanesthetic ketamine infusion of 0.5 mg/kg/h. Further evaluations were divided into three phases: anesthetic, early postanesthetic (48 hours), and remote at 4 months after procedure. Cardiovascular, respiratory, renal, and gastrointestinal responses to opiate antagonist induction were monitored during anesthesia phase. Changes in plasma cortisol concentrations were measured as stress-response markers. Evaluations during early postanesthetic phase were based on Subjective and Objective Opiate Withdrawal Scales. Remote effects were assessed according to questionnaire based on Addiction Severity Index.

RESULTS

Altogether, 50 patients were included in the final analysis. Ketamine group presented better control of withdrawal symptoms, which lasted beyond ketamine infusion itself. Significant differences between Ketamine and Control groups were noted in anesthetic and early postanesthetic phases. There were no differences in effects on outcome after 4 months.

CONCLUSION

In this study, subanesthetic ketamine infusion was an effective adjuvant in the correction of acute precipitated opiate withdrawal although it had no long-term effects on treatment of opiate dependence.

Determinants of outcome in elderly patients admitted to the intensive care unit

BACKGROUND

Age is thought to be strongly associated with intensive care outcomes, but this relationship may be confounded by many clinical variables.

OBJECTIVES

To compare clinical characteristics of elderly patients (> or = 65 years) admitted to the intensive care unit (ICU) with those in younger patients and to identify the risk factors which independently could predict mortality in patients aged > or = 75 years.

DESIGN

Prospective observational cohort study.

SETTING

Medical-surgical ICU in a university hospital.

SUBJECTS

2,067 adult patients admitted to the ICU.

METHODS

Comparison of clinical characteristics of patients divided into groups according to their age.

RESULTS

Elderly patients comprised 51% of the study population. Compared with younger patients, elderly patients were more severely ill on admission, had shock and renal dysfunction. The presence of infection on admission and the incidence rate of infection acquired during stay in the ICU also significantly increased with age. Hospital mortality increased with age: for patients aged > or = 75 years, it was more than double that of patients aged <65 years (39% versus 19%, P < 0.001). Using multivariate logistic regression analysis we determined the independent risk factors of hospital mortality for the patients aged > or = 75 years: impaired level of consciousness, infection on admission, ICU-acquired infection and severity of illness score.

CONCLUSIONS

Morbidity and mortality in elderly patients admitted to the ICU are higher than in younger patients. The most important factors independently associated with the highest risk of death are the severity of illness, impaired level of consciousness and infection.

[Safety and effectiveness of opiate antagonist detoxification under general anesthesia]

OBJECTIVE

To evaluate safety and effectiveness of opiate antagonist detoxification under general anesthesia according to available prospective and retrospective data.

METHODS

We analyzed all detoxification cases that were performed in Vilnius University Emergency Hospital in the period of 2002-2005. Data of 65 patients from prospective, randomized, double-blind, placebo-controlled study and 21 retrospective cases were included in the study.

RESULTS

Full opiate receptor blockade was achieved in 85 cases (98.84%). No complications related to detoxification procedure or general anesthesia were recorded. Differences in procedure protocols and possible implications for clinical practice are discussed.

CONCLUSIONS

The protocol of the prospective study may be recommended as a safe and effective detoxification method.

Sequential organ failure assessment score as the determinant of outcome for patients with severe sepsis

AIM

To evaluate the impact of organ dysfunction in severe sepsis and determine the effectiveness of organ dysfunction scores to discriminate outcome after admission to the intensive care unit (ICU).

METHODS

Patients with a diagnosis of severe sepsis and at least one organ dysfunction on the first day in the ICU (n=117) were included in the prospective observational study. The presence of organ dysfunction was assessed using a Sequential Organ Failure Assessment (SOFA). The severity of illness was assessed using a Simplified Acute Physiology Score (SAPS) II during the first 24 hours after the admission to the ICU. The main outcome was survival status on day 28 after admission to the ICU.

RESULTS

Most common sites of infection were intra-abdominal and respiratory system (77 and 38 cases, respectively). Median SAPS II score on admission was 47 points (25th-75th quartiles range, 37-57 points). Twenty eight days survival rate was 41%. The best discrimination results were shown for cumulative scores with the highest for the SOFA score on day 3 in the ICU. The ability to discriminate outcome on day 1 was weak for the presence of dysfunction in all organ systems except neurological. The discriminative power of organ dysfunction scores increased during the stay in the ICU. Neurological and cardiovascular dysfunctions were the independent risk factors for mortality.

CONCLUSION

The SOFA scores showed high accuracy in describing the course of organ dysfunction for the patients with severe sepsis. Evolving organ dysfunction following admission to the ICU strongly affected the outcome. Cumulative SOFA scores were better in discriminating outcome compared to single organ dysfunction scores.

Evaluation of intensive care unit performance in Lithuania using the SAPS II system

BACKGROUND AND OBJECTIVE

Outcome prediction and evaluation of intensive care unit (ICU) performance using severity of illness scoring is a tool for the estimation of effectiveness and quality of intensive care. We used the simplified acute physiology score (SAPS) II system to evaluate ICU performance.

METHODS

The present study is a prospective observational study in an ICU at Vilnius University Emergency Hospital, Lithuania. The observed death rate was compared with the predicted death rate calculated using SAPS II system. The ability of the SAPS II prognostic system to predict the probability of hospital mortality was assessed with discrimination and calibration measures.

RESULTS

Two-thousand-and-sixty-seven patients consecutively admitted to the ICU were studied. The median SAPS II score on the first ICU day was 29. The SAPS II system showed a good ability to separate those patients predicted to live from those predicted to die (an area under the receiver operating characteristic curve was 0.883). The calibration curve demonstrated under-prediction of the actual death rate (Hosmer-Lemeshow goodness-of-fit test, chi2 = 56.98; df = 8; P < 0.001). The observed mortality was higher than predicted by the SAPS II equation (observed to predicted ratio is 1.28).

CONCLUSIONS

The SAPS II system is a useful tool for the assessment of ICU performance. This system demonstrated a good ability of discrimination, but an under-prediction of the actual mortality rate, in Lithuanian ICUs.

Intensive care unit acquired infection: a prevalence and impact on morbidity and mortality

BACKGROUND

Severe infection is a common reason for intensive care and contributes to increased morbidity and mortality. The aim of the study was to determine the prevalence of infection among intensive care unit (ICU) patients and to evaluate the consequences of ICU-acquired infection on morbidity and mortality.

METHODS

A total of 812 patients consecutively admitted for more than 48 h to the ICU at Vilnius University Emergency Hospital, Lithuania, were included in the prospective observational study. Organ dysfunction was assessed using the Sequential Organ Failure Assessment (SOFA) system.

RESULTS

Thirty-seven per cent of patients were identified who developed at least one ICU-acquired infection. Respiratory, bloodstream and urinary tract infections were the most common. The main isolates were coagulase-negative Staphylococcus, S. aureus, Acinetobacter and Pseudomonas species. More severe degree of organ dysfunction, prolonged stay in the ICU and higher hospital mortality rate were more common among patients who acquired infection in the ICU than that of non-infected patients.

CONCLUSION

The prevalence of infection in the ICU was similar to other studies in European countries. The occurrence of ICU-acquired infection was significantly related to the increase in morbidity and mortality. The findings are useful for the comparison of the prevalence rate of infection and implementation of strict infection control policy.

[Clinical information system and its significance in intensive care]

The increasing number of the patients requiring admission to the intensive care unit and growing demand for the outcome analysis was noted over the last decade. The goal of this study was to evaluate the characteristics of the patients, to compare the outcome of surgical and medical patients, and to demonstrate the importance of the clinical information system in the intensive care. During 12-month period 1031 patients were enrolled for the study. Data were collected on forms and then entered into a computer program specifically designed for this study. For the overall population mean age was 63 years, Simplified Acute Physiology Score II (SAPS II)--31, and stay in the intensive care unit--4 days. The most frequent site of the intensive care unit acquired infection was respiratory, mainly pneumonia. The overall mortality in the intensive care unit was 19.4% and hospital mortality--24.8%. The mortality was directly associated with advanced age, increased SAPS II sore, and the occurrence of organ dysfunction. Medical patients in comparison with surgical patients had higher SAPS II scores (p < 0.001) and number of organ dysfunctions (p < 0.001), longer intensive care unit stay (p < 0.001) and higher mortality rate (p < 0.001). The underprediction of actual mortality by the SAPS II system was predetermined by this value of the neurological patients. The outcome of the surgical patients was good compared to the results of the studies from other countries. Clinical information system is necessary for comprehensive and objective evaluation of the intensive care unit data and quality of therapy.