Miljenko Križmarić

Partial pressure of end-tidal carbon dioxide successful predicts cardiopulmonary resuscitation in the field: a prospective observational study.

IntroductionPrognosis in patients suffering out-of-hospital cardiac arrest is poor. Higher survival rates have been observed only in patients with ventricular fibrillation who were fortunate enough to have basic and advanced life support initiated soon after cardiac arrest. An ability to predict cardiac arrest outcomes would be useful for resuscitation. Changes in expired end-tidal carbon dioxide levels during cardiopulmonary resuscitation (CPR) may be a useful, noninvasive predictor of successful resuscitation and survival from cardiac arrest, and could help in determining when to cease CPR efforts.MethodsThis is a prospective, observational study of 737 cases of out-of-hospital cardiac arrest. The patients were intubated and measurements of end-tidal carbon dioxide taken. Data according to the Utstein criteria, demographic information, medical data, and partial pressure of end-tidal carbon dioxide (PetCO2) values were collected for each patient in cardiac arrest by the emergency physician. We hypothesized that an end-tidal carbon dioxide level of 1.9 kPa (14.3 mmHg) or more after 20 minutes of standard advanced cardiac life support would predict restoration of spontaneous circulation (ROSC).ResultsPetCO2 after 20 minutes of advanced life support averaged 0.92 ± 0.29 kPa (6.9 ± 2.2 mmHg) in patients who did not have ROSC and 4.36 ± 1.11 kPa (32.8 ± 9.1 mmHg) in those who did (P < 0.001). End-tidal carbon dioxide values of 1.9 kPa (14.3 mmHg) or less discriminated between the 402 patients with ROSC and 335 patients without. When a 20-minute end-tidal carbon dioxide value of 1.9 kPa (14.3 mmHg) or less was used as a screening test to predict ROSC, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%.ConclusionsEnd-tidal carbon dioxide levels of more than 1.9 kPa (14.3 mmHg) after 20 minutes may be used to predict ROSC with accuracy. End-tidal carbon dioxide levels should be monitored during CPR and considered a useful prognostic value for determining the outcome of resuscitative efforts and when to cease CPR in the field.

Impact of Modified Treatment in Echocardiographically Confirmed Pseudo-Pulseless Electrical Activity in Out-of-Hospital Cardiac Arrest Patients with Constant End-Tidal Carbon Dioxide Pressure during Compression Pauses

This study evaluated the ability of focused echocardiography (FE) and capnography to differentiate between pulseless electrical activity (PEA) and pseudo-PEA in out-of-hospital cardiac arrest, and the potential survival benefits with modified treatment. In PEA patients with stable end-tidal carbon dioxide pressure (P etCO2) during the compression pause and concomitant FE showing cardiac kinetic activity, the compression pause was prolonged for 15 s and an additional 20 IU vasopressin was administered. If pulselessness persisted, compressions were continued. Fifteen of the 16 patients studied (94%) achieved restoration of spontaneous circulation (ROSC); eight patients (50%) attained a good neurological outcome (Cerebral Performance Category 1–2). In an historical PEA group with stable P etCO2 values (n = 48), ROSC was achieved in 26 patients (54%); four patients (8%) attained Cerebral Performance Category 1–2. Echocardiographical verification of the pseudo-PEA state enabled additional vasopressor treatment and cessation of chest compressions, and was associated with significantly higher rates of ROSC, survival to discharge and good neurological outcome.

The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest

IntroductionPartial pressure of end-tidal carbon dioxide (PetCO2) during cardiopulmonary resuscitation (CPR) correlates with cardiac output and consequently has a prognostic value in CPR. In our previous study we confirmed that initial PetCO2 value was significantly higher in asphyxial arrest than in ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) cardiac arrest. In this study we sought to evaluate the pattern of PetCO2 changes in cardiac arrest caused by VF/VT and asphyxial cardiac arrest in patients who were resuscitated according to new 2005 guidelines.MethodsThe study included two cohorts of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity (PEA), and cardiac arrest due to arrhythmia with initial rhythm VF or pulseless VT. PetCO2 was measured for both groups immediately after intubation and repeatedly every minute, both for patients with or without return of spontaneous circulation (ROSC). We compared the dynamic pattern of PetCO2 between groups.ResultsBetween June 2006 and June 2009 resuscitation was attempted in 325 patients and in this study we included 51 patients with asphyxial cardiac arrest and 63 patients with VF/VT cardiac arrest. The initial values of PetCO2 were significantly higher in the group with asphyxial cardiac arrest (6.74 ± 4.22 kilopascals (kPa) versus 4.51 ± 2.47 kPa; P = 0.004). In the group with asphyxial cardiac arrest, the initial values of PetCO2 did not show a significant difference when we compared patients with and without ROSC (6.96 ± 3.63 kPa versus 5.77 ± 4.64 kPa; P = 0.313). We confirmed significantly higher initial PetCO2 values for those with ROSC in the group with primary cardiac arrest (4.62 ± 2.46 kPa versus 3.29 ± 1.76 kPa; P = 0.041). A significant difference in PetCO2 values for those with and without ROSC was achieved after five minutes of CPR in both groups. In all patients with ROSC the initial PetCO2 was again higher than 1.33 kPa.ConclusionsThe dynamic pattern of PetCO2 values during out-of-hospital CPR showed higher values of PetCO2 in the first two minutes of CPR in asphyxia, and a prognostic value of initial PetCO2 only in primary VF/VT cardiac arrest. A prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until final values. This difference seems to be a useful criterion in pre-hospital diagnostic procedures and attendance of cardiac arrest.

Capnometry in suspected pulmonary embolism with positive D-dimer in the field

IntroductionPulmonary embolism (PE) is one of the greatest diagnostic challenges in prehospital emergency setting. Most patients with suspected PE have a positive D-dimer and undergo diagnostic testing. Excluding PE with additional non-invasive tests would reduce the need for further imaging tests. We aimed to determine the effectiveness of combination of clinical probability and end-tidal carbon dioxide (PetCO2) for evaluation of suspected PE with abnormal concentrations of D-dimer in prehospital emergency setting.MethodsWe assessed clinical probability of PE and PetCO2 measurement in 100 consecutive patients with suspected PE and positive D-dimer in the field. PetCO2 > 28 mmHg was considered as the best cut-off point. PE was excluded or confirmed by hospital physicians in the University Clinical Center Maribor by computer tomography (CT), ventilation/perfusion scan echocardiography and pulmonary angiography.ResultsPE was confirmed in 41 patients. PetCO2 had a sensitivity of 92.6% (95% CI, 79 to 98%), a negative predictive value of 94.2% (95% CI, 83 to 99%), a specificity of 83% (95% CI, 71 to 91%) and a positive predictive value of 79.2% (95% CI, 65 to 89%). Thirty-five patients (35%) had both a low (PE unlikely) clinical probability and a normal PetCO2 (sensitivity: 100%, 95% CI: 89 to 100%) and twenty-eight patients (28%) had both a high clinical probability (PE likely) and abnormal PetCO2 (specificity: 93.2%, 95% CI: 83 to 98%).ConclusionsThe combination of clinical probability and PetCO2 may safely rule out PE in patients with suspected PE and positive D-dimer in the prehospital setting.

Impact of additional module training on the level of basic life support knowledge of first year students at the University of Maribor

AimThe aim of this study was to investigate the impact of additional (two versus one session) basic life support (BLS) training of university students on knowledge and attitude concerning the performance of cardiopulmonary resuscitation.MethodsA total of 439 students in three separate groups were tested: those with no prior BLS training; BLS training in high school (part of the drivers education course); and BLS training in high school (in the drivers education course) and additional BLS training at the university.ResultsOur study showed the best results of BLS education in a group of university students who took an additional BLS module approximately half a year after the drivers education BLS course. In our study we observed equal levels of knowledge between the group with BLS training in high school and the group without any formal BLS education. The questionnaire revealed a disappointing level of knowledge about BLS in both groups.ConclusionAdditional basic life support training (two BLS training sessions: high school and university) improves retention of knowledge and attitudes concerning performing CPR in first year university students.

Pseudocholinesterase activity in cerebrospinal fluid as a biomarker of solid central nervous system tumors in children.

Aim To determine the activity of pseudocholinesterase (PChE) in cerebrospinal fluid (CSF) and serum in children with solid central nervous system (CNS) tumor and to assess whether PChE activity could be a valid biomarker for solid CNS tumors in children. Methods The study and control group included 30 children each. Children in the study group had a solid CNS tumor, while those from the control group had never suffered from any tumor diseases. CSF and serum samples were collected from all participants and PChE activity was determined using the Ellman’s spectrophotometric method. PChE activity in CSF was shown as a cerebrospinal fluid/serum ratio expressed in percentage, ie, PChE CSF/serum ratio. Receiver operating characteristic (ROC) curve was used to assess whether PChE activity can be used as a biomarker for identifying children with solid CNS tumors. Results Children with solid CNS tumor had significantly higher PChE activity in CSF and serum, as well as PChE CSF/serum ratio (P = 0.001). PChE CSF/serum ratio in the study group was 2.38% (interquartile range [IQR] 1.14-3.97) and 1.09% (IQR 0.95-1.45) in the control group. ROC curve analysis of PChE CSF/serum ratio resulted in an area under the curve (AUC) value of 0.76 (95% confidence interval [CI] 0.63-0.88) and a cut-off of 1.09. Twenty five of 29 patients with elevated PChE CSF/serum ratio had a tumor, corresponding to a sensitivity of 83% and a specificity of 53%. Conclusion PChE CSF/serum ratio may be used as a test or biomarker with good sensitivity for solid CNS tumors in children.

Risk factors for fatal outcome in patients with opioid dependence treated with methadone in a family medicine setting in Croatia.

Aim To determine the risk factors for fatal outcome in patients with opioid dependence treated with methadone at the primary care level. Methods A group of 287 patients with opioid dependence was monitored prospectively from 1995 to 2007. At the beginning of the study, we collected the data on patient baseline characteristics, treatment characteristics, and living environment. At the annual check-up, we collected the data on daily methadone dose, method of methadone therapy administration, and family physician’s assessment of the patient’s drug use status. Results Out of 287 patients, 8% died. Logistic regression analysis showed that the predictors of fatal outcome were continuation of drug use during previous therapeutic attempts (odds ratio [OR], 19.402; 95% confidence interval [CI], 1.659-226.873), maintenance therapy as the planned treatment modality (OR, 3.738; 95% CI, 1.045-13.370), living in an unstable relationship (OR, 9.275; 95% CI, 2.207-38.984), and loss of continuity of care (OR, 12.643; 95% CI, 3.001-53.253). Conclusion The patients presenting these risk factors require special attention. It is important for family physicians to insist on compliance with the treatment protocol and intervene when they lose contact with the patient to prevent the fatal outcome.

Predictors of mortality in patients with isolated severe traumatic brain injury

SummaryBackgroundTraumatic brain injury (TBI) is a leading cause of death and disability worldwide. Many prognostic models predicting mortality in patients with TBI were developed, which also include patients with mild or moderate TBI and patients who suffered major extracranial injuries.MethodsFrom a prospective database, we conducted a retrospective medical chart review covering the period between January 2000 and December 2012 of patients with isolated severe TBI (Abbreviated Injury Score for head, AISH ≥ 3) without extracranial injuries, who were intubated in the field using the rapid sequence intubation method and were of age 16 or more. Prehospital vital signs, Injury Severity Score (ISS) and laboratory tests were compared in two study groups: survivors (n = 25) and non-survivors (n = 27). Selected variables identified during univariate analysis (p < 0.1) were then subjected to multivariate analysis logistic regression model.ResultsUnivariate analysis showed that in-hospital mortality was statistically significantly associated with male sex (p = 0.040), ISS (p = 0.005) and mydriasis (p = 0.012). For predicting mortality, area under the curve (AUC) was calculated: for ISS 0.76 (95 % confidence interval, CI; 0.63–0.90; p < 0.001) and for initial Glasgow Coma Scale (GCS) 0.64 (95 % CI, 0.49–0.80, p = 0.079). In the multivariate analysis, ISS (odds ratio, OR; 1.19, 95 % CI, 1.06–1.35; p = 0.004) and mydriasis (OR, 5.73; 95 % CI, 1.06–30.88; p = 0.042) were identified as independent risk factors for in-hospital mortality. The AUC for the regression model was 0.83 (95 % CI, 0.71–0.94; p < 0.001).ConclusionsIn prehospital intubated patients with isolated severe TBI only ISS and mydriasis were found to be independent predictors of in-hospital mortality.

New Insights into the Evolutionary and Genomic Landscape of Molluscum Contagiosum Virus (MCV) based on Nine MCV1 and Six MCV2 Complete Genome Sequences

Molluscum contagiosum virus (MCV) is the sole member of the Molluscipoxvirus genus and the causative agent of molluscum contagiosum (MC), a common skin disease. Although it is an important and frequent human pathogen, its genetic landscape and evolutionary history remain largely unknown. In this study, ten novel complete MCV genome sequences of the two most common MCV genotypes were determined (five MCV1 and five MCV2 sequences) and analyzed together with all MCV complete genomes previously deposited in freely accessible sequence repositories (four MCV1 and a single MCV2). In comparison to MCV1, a higher degree of nucleotide sequence conservation was observed among MCV2 genomes. Large-scale recombination events were identified in two newly assembled MCV1 genomes and one MCV2 genome. One recombination event was located in a newly identified recombinant region of the viral genome, and all previously described recombinant regions were re-identified in at least one novel MCV genome. MCV genes comprising the identified recombinant segments have been previously associated with viral interference with host T-cell and NK-cell immune responses. In conclusion, the two most common MCV genotypes emerged along divergent evolutionary pathways from a common ancestor, and the differences in the heterogeneity of MCV1 and MCV2 populations may be attributed to the strictness of the constraints imposed by the host immune response.

Arterial blood gas changes during cardiac arrest and cardiopulmonary resuscitation combined with passive oxygenation/ventilation: a METI HPS study

Objective High-fidelity simulators can simulate physiological responses to medical interventions. The dynamics of the partial arterial pressure of oxygen (PaO2), partial arterial pressure of carbon dioxide (PaCO2), and oxygen pulse saturation (SpO2) during simulated cardiopulmonary resuscitation (CPR) were observed and compared with the results from the literature. Methods Three periods of cardiac arrest were simulated using the METI Human Patient Simulator™ (Medical Education Technologies, Inc., Sarasota, FL, USA): cardiac arrest, chest compression-only CPR, and chest compression-only CPR with continuous flow insufflation of oxygen (CFIO). Results In the first period, the observed values remained constant. In the second period, PaCO2 started to rise and peaked at 63.5 mmHg. In the CFIO period, PaCO2 slightly fell. PaO2 and SpO2 declined only in the second period, reaching their lowest values of 44 mmHg and 70%, respectively. In the CFIO period, PaO2 began to rise and peaked at 614 mmHg. SpO2 exceeded 94% after 2 minutes of CFIO. Conclusions The METI Human Patient Simulator™ accurately simulated the dynamics of changes in PaCO2. Use of this METI oxygenation model has some limitations because the simulated levels of PaO2 and SpO2 during cardiac arrest correlate poorly with the results from published studies.