P Dostal

Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline

IntroductionPre-hospital induction of therapeutic mild hypothermia (TH) may reduce post-cardiac arrest brain injury in patients resuscitated from out-of-hospital cardiac arrest. Most often, it is induced by a rapid intravenous administration of as much as 30 ml/kg of cold crystalloids. We decided to assess the pre-hospital cooling effectivity of this approach by using a target dose of 15-20 ml/kg of 4°C cold normal saline in the setting of the physician-staffed Emergency Medical Service. The safety and impact on the clinical outcome have also been analyzed.MethodsWe performed a prospective observational study with a retrospective control group. A total of 40 patients were cooled by an intravenous administration of 15-20 ml/kg of 4°C cold normal saline during transport to the hospital (TH group). The pre-hospital decrease of tympanic temperature (TT) was analyzed as the primary endpoint. Patients in the control group did not undergo any pre-hospital cooling.ResultsIn the TH group, administration of 12.6 ± 6.4 ml/kg of 4°C cold normal saline was followed by a pre-hospital decrease of TT of 1.4 ± 0.8°C in 42.8 ± 19.6 min (p < 0.001). The most effective cooling was associated with a transport time duration of 38-60 min and with an infusion of 17 ml/kg of cold saline. In the TH group, a trend toward a reduced need for catecholamines during transport was detected (35.0 vs. 52.5%, p = 0.115). There were no differences in demographic variables, comorbidities, parameters of the cardiopulmonary resuscitation and in other post-resuscitation characteristics. The coupling of pre-hospital cooling with subsequent in-hospital TH predicted a favorable neurological outcome at hospital discharge (OR 4.1, CI95% 1.1-18.2, p = 0.046).ConclusionsPre-hospital induction of TH by the rapid intravenous administration of cold normal saline has been shown to be efficient even with a lower dose of coolant than reported in previous studies. This dose can be associated with a favorable impact on circulatory stability early after the return of spontaneous circulation and, when coupled with in-hospital continuation of cooling, can potentially improve the prognosis of patients.Trial RegistrationClinicalTrials (NCT): NCT00915421

Blood and tissue glucose level in critically ill patients: a comparison of different methods of measuring interstitial glucose levels

Sir: Tight glycemic control in critically ill patients may significantly decrease their mortality and morbidity. Mini-invasive techniques for continuous glucose monitoring [the Guardian Real Time (RT) continuous glucose monitoring system and the microdialysis technique] are promising methods for glucose management but clinical trials evaluating the correlation with plasma glucose levels in critically ill patients are missing. To investigate whether the glucose values obtained by the Guardian RT system and microdialysis could be used instead of blood glucose sampling in mechanically ventilated, critically ill patients we performed a prospective study in which we enrolled 15 patients aged 18 and over, admitted to a multidisciplinary ICU and the preliminary results we presented at the 28th International Symposium on Intensive Care and Emergency Medicine and Euroanasthesia 2008 Congress [1, 2]. A microdialysis catheter (CMA 60, 0.5 9 30 mm membrane, 20 kDa cut-off, CMA Microdialysis, Solna, Sweden), inserted into the subcutaneous adipose tissue in the abdominal area was constantly perfused with normal saline at a flow rate of 0.3 lL/min. The dialysate was collected in hourly fractions. A sensor of the Guardian RT system, Medtronic, Inc. (NYSE: MDT), was inserted simultaneously subcutaneously in the abdominal area opposite to the microdialysis catheter. Arterial blood samples were collected from the arterial catheter in hourly fractions (at the time of microvial replacement), analyzed for plasma glucose in the Central Laboratory and paired with the microdialysis and Guardian RT values recorded at the time of microvial replacement. Experiment ran for 24 h. Two hundred and thirty-six arterial blood samples, microdialysate and Guardian glucose readings were analyzed. The data were described as the median ± IQR (interquartile range) and the Pearson coefficient of correlation and the Bland Altman plot were calculated. The P values \0.05 were considered as statistically significant. The median arterial plasma glucose level was 6.2 (5.1; 7.8) mmol/L. The median Guardian RT glucose level was 5.75 (4.5; 7.2) mmol/L and the median microdialysis glucose level was 3.8 (2.5; 5.2) mmol/L. The correlation coefficient between arterial plasma glucose and the microdialysis interstitial glucose level was r = 0.7044. The correlation coefficient between arterial plasma glucose and Guardian RT readings was r = 0.6938. This was confirmed by the Bland Altman plot with broad limits of agreement. According to the observed, clinically unacceptable broad limits of agreement, microdialysis and the Guardian RT system could not be considered equivalent to blood glucose measurement and our findings do not support their use for the tight glycemic control management in mechanically ventilated, critically ill patients.

A comparison of equivolume, equiosmolar solutions of hypertonic saline and mannitol for brain relaxation in patients undergoing elective intracranial tumor surgery: a randomized clinical trial.

Background: Hyperosmolar solutions have been used in neurosurgery to modify brain bulk and prevent neurological deterioration. The purpose of the study was to compare the effects of equivolume, equiosmolar solutions of mannitol and hypertonic saline (HTS) on brain relaxation and postoperative complications in patients undergoing elective intracranial tumor surgery. Methods: In this prospective, randomized study, patients with American Society of Anesthesiologists physical status I to III scheduled to undergo a craniotomy for intracranial tumors were enrolled. Patients received a 3.75 mL/kg intravenous infusion of either 3.2% HTS (group HTS, n=36) or 20% mannitol (group M, n=38). The surgeon assessed the condition of the brain using a 4-point scale after opening the dura. Recorded measures included duration of surgery, blood loss, urine output, volume and type of infused fluids, hemodynamic variables, electrolytes, glucose, creatinine, predefined postoperative complications, and length of intensive care unit and hospital stays. Results: Brain relaxation conditions in group HTS (score 1/2/3/4, n=10/17/2/7) were better than those in group M (score 1/2/3/4, n=3/18/3/14, P=0.0281). Patients in group M had higher urine output, received more crystalloids during surgery, and displayed lower central venous pressure and lower natremia at the end of surgery than did patients in group HTS. No significant differences in postoperative complications or lengths of intensive care unit and hospital stays were observed between the groups. Conclusions: Our results suggest that HTS provides better brain relaxation than mannitol during elective intracranial tumor surgery.

Comparison of cold crystalloid and colloid infusions for induction of therapeutic hypothermia in a porcine model of cardiac arrest

IntroductionLarge-volume cold intravenous infusion of crystalloids has been used for induction of therapeutic hypothermia after cardiac arrest. However, the effectiveness of cold colloids has not been evaluated. Therefore, we performed an experimental study to investigate the cooling effect of cold normal saline compared to colloid solution in a porcine model of ventricular fibrillation.MethodsVentricular fibrillation was induced for 15 minutes in 22 anesthetized domestic pigs. After spontaneous circulation was restored, the animals were randomized to receive either 45 ml/kg of 1°C cold normal saline (Group A, 9 animals); or 45 ml/kg of 1°C cold colloid solution (Voluven®, 6% hydroxyethyl starch 130/0.4 in 0.9% NaCl) during 20 minutes (Group B, 9 animals); or to undergo no cooling intervention (Group C, 4 animals). Then, the animals were observed for 90 minutes. Cerebral, rectal, intramuscular, pulmonary artery, and subcutaneous fat body temperatures (BT) were recorded. In the mechanical ex-vivo sub study we added a same amount of cold normal saline or colloid into the bath of normal saline and calculated the area under the curve (AUC) for induced temperature changes.ResultsAnimals treated with cold fluids achieved a significant decrease of BT at all measurement sites, whereas there was a consistent significant spontaneous increase in group C. At the time of completion of infusion, greater decrease in pulmonary artery BT and cerebral BT in group A compared to group B was detected (−2.1 ± 0.3 vs. -1.6 ± 0.2°C, and −1.7 ± 0.4 vs. -1.1 ± 0.3°C, p < 0.05, respectively). AUC analysis of the decrease of cerebral BT revealed a more vigorous cooling effect in group A compared to group B (−91 ± 22 vs. -68 ± 23°C/min, p = 0.046). In the mechanical sub study, AUC analysis of the induced temperature decrease of cooled solution revealed that addition of normal saline led to more intense cooling than colloid solution (−7155 ± 647 vs. -5733 ± 636°C/min, p = 0.008).ConclusionsIntravenous infusion of cold normal saline resulted in more intense decrease of cerebral and pulmonary artery BT than colloid infusion in this porcine model of cardiac arrest. This difference is at least partially related to the various specific heat capacities of the coolants.

Prehospital cooling by cold infusion: searching for the optimal infusion regimen

Background The cooling efficacy of intravenous administration of cold crystalloids can be enhanced by optimisation of the procedure. This study assessed the temperature stability of different application regimens of cold normal saline (NS) in simulated prehospital conditions. Methods Twelve different application regimens of 4°C cold NS (volumes of 250, 500 and 1000 ml applied at infusion rates of 1000, 2000, 4000 and 6000 ml/h) were investigated for infusion temperature changes during administration to an artificial detention reservoir in simulated prehospital conditions. Results An increase in infusion temperature was observed in all regimens, with an average of 8.1±3.3°C (p<0.001). This was most intense during application of the residual 20% of the initial volume. The lowest rewarming was exhibited in regimens with 250 and 500 ml bags applied at an infusion rate of 6000 ml/h and 250 ml applied at 4000 ml/h. More intense, but clinically acceptable, rewarming presented in regimens with 500 and 1000 ml bags administered at 4000 ml/h, 1000 ml at 6000 ml/h and 250 ml applied at 2000 ml/h. Other regimens were burdened by excessive rewarming. Conclusion Rewarming of cold NS during application in prehospital conditions is a typical occurrence. Considering that the use of 250 ml bags means the infusion must be exchanged too frequently during cooling, the use of 500 or 1000 ml NS bags applied at an infusion rate of ≥4000 ml/h and termination of the infusion when 80% of the infusion volume has been administered is regarded as optimal.

Assessment of regional ventilation with the electrical impedance tomography in a patient after asphyxial cardiac arrest.

Survival from cardiac arrest presenting initially with asystole r pulseless electrical activity is very unlikely unless all relevant eversible causes are recognized and treated effectively.1 In some atients, extensive differential diagnosis is needed to ascertain he cause of cardiac arrest, especially if differentiation between ardiovascular and respiratory aetiology is necessary. Routine iniial evaluation, including chest X-ray may not be sufficient to iagnose alterations in distribution of ventilation that may be resent in some respiratory disorders. Although examination with hest ultrasound could assess lung and pleural cavity pathologies,2 his technique requires expertise and does not directly quantify egional ventilation, while the benefits of computed tomography CT) should always be weighted to the risks and disadvantages f patient’s intra-hospital transportation. Use of a non-invasive ethod, an electrical impedance tomography (EIT), which has lready been used for assessment of lung volumes and distribution f ventilation under various clinical conditions,3,4 has not become ommon in post-resuscitation care. We report the case of a 61-year-old man admitted after sucessful resuscitation from asystolic out-of-hospital cardiac arrest OHCA) following a short period of severe dyspnoea. His per-

Implementation of pre-hospital therapeutic hypothermia in post-cardiac arrest patients in the Czech Republic

In the Czech Republic, post-cardiac arrest therapeutic hypotheria is now commonly used in hospitals.1 Indeed, the physiciantaffed emergency medical service system, and a network of ercutaneous coronary intervention centres offer a high-level ost-cardiac arrest care. This also now includes the pre-hospital nitiation of therapeutic hypothermia. After a feasibility study and ocal implementation of pre-hospital cooling, we undertook a surey about pre-hospital therapeutic hypothermia use in the Czech epublic.2 In October 2010, all physician members of the Czech ociety for Emergency and Disaster Medicine were sent a webased questionnaire. Fifty-five percent (126 out of 227) of the physicians responded. f these, 52 (41.3%) had used pre-hospital therapeutic hypothermia Fig. 1). Physicians who used pre-hospital therapeutic hypothermia sed it in about half of cases (45.4 ± 25.9%). A strong predicor of pre-hospital therapeutic hypothermia use was attendance y a physician with five or less years of pre-hospital emergency edicine experience (OR 5.6, 95%CI 1.8–19.7, p = 0.004). Taking part n, or knowledge of a local clinical study (PRE-COOL) was a strong redictor (n = 22, 42.3%), as well as familiarity with current Euroean and, or Czech resuscitation guidelines (n = 21, 40.4%).2–4 A ritten pre-hospital cooling protocol was used by 86.5% (n = 45) f the responders using pre-hospital therapeutic hypothermia. hirty-two (61.5%) of the pre-hospital therapeutic hypothermia sers accepted a broad indication for cooling irrespective of the iniial rhythm, the presence of witnesses and whether the supposed rigin was a cardiac or not. The need for vasopressors was given s a reason for not using pre-hospital therapeutic hypothermia by 7 (32.7%), suspected pulmonary embolism by 31 (59.6%), age less han 18 years by 25 (48.1%), and pregnancy by 43 (82.7%) of preospital therapeutic hypothermia users. The most frequently used ooling method was infusion of cold crystalloids (n = 44, 84.6%). Surace cooling with ice-packs was used less frequently (n = 14, 26.9%) nd other techniques (intranasal cooling, EMCOOLS) were rarely sed (n = 2, 3.8%). Only half of the respondents sedated patients outinely and 36.5% (n = 19) of the respondents never or rarely sed neuromuscular blocking agents during pre-hospital therapeuic hypothermia. Tympanic temperature was measured by 78.8% n = 41) of responders. A third of responders used pre-hospital herapeutic hypothermia without temperature measurement at aseline and on hospital arrival. Of non-users, 33.8% planned to mplement the use of pre-hospital therapeutic hypothermia as soon s possible. Common reasons for non-use were lack of equipment 59.1%), no in-hospital cooling in the local hospital (27.3%), lack f supporting evidence for pre-hospital therapeutic hypothermia 21.2%), and short transport times (15.1%).

Effects of Hypertonic Saline and Sodium Lactate on Cortical Cerebral Microcirculation and Brain Tissue Oxygenation.

Background: Hyperosmolar solutions have been used in neurosurgery to modify brain bulk. The aim of this animal study was to compare the short-term effects of equivolemic, equiosmolar solutions of hypertonic saline (HTS) and sodium lactate (HTL) on cerebral cortical microcirculation and brain tissue oxygenation in a rabbit craniotomy model. Methods: Rabbits (weight, 1.5 to 2.0 kg) were anesthetized, ventilated mechanically, and subjected to a craniotomy. The animals were allocated randomly to receive a 3.75 mL/kg intravenous infusion of either 3.2% HTS (group HTS, n=9), half-molar sodium lactate (group HTL, n=10), or normal saline (group C, n=9). Brain tissue partial pressure of oxygen (PbtO2) and microcirculation in the cerebral cortex using sidestream dark-field imaging were evaluated before, 20 and 40 minutes after 15 minutes of hyperosmolar solution infusion. Global hemodynamic data were recorded, and blood samples for laboratory analysis were obtained at the time of sidestream dark-field image recording. Results: No differences in the microcirculatory parameters were observed between the groups before and after the use of osmotherapy. Brain tissue oxygen deteriorated over time in groups C and HTL, this deterioration was not significant in the group HTS. Conclusions: Our findings suggest that equivolemic, equiosmolar HTS and HTL solutions equally preserve perfusion of cortical brain microcirculation in a rabbit craniotomy model. The use of HTS was better in preventing the worsening of brain tissue oxygen tension.

Elam-1 plasma levels as a early predictor of adult respiratory distress syndrome

Introduction: Polymorphonuclear neutrophils (PMN)-endothelial interactions seem to play an important role during inflammatory response that is out of the proportion to the original stimulus and is implicated in the pathogenesis of organ injury including adult respiratory distress syndrome (ARDS). The molecular basis of PMN-endothelial interaction is dependent on groups of adhesion molecules such as integrins and selectins. E-selectin (ELAM-1) is a circulating marker specific for endothelial activation and endothelial damage induced by a variety of inflammatory mediators including TNF alpha, interleukins and endotoxin and its maximal surface expression after stimulation occurs at about 4 hours in vitro. The aim of the study was prospectively evaluate the serum levels of E-selectin in patients at high risk of development of ARDS. We expected to observe higher E-selectin levels in patients who would subsequently develop ARDS. Methods: Thirteen critically ill patients (7 trauma, 6 non trauma) requiring ventilatory support were prospectively studied. None of the patients had signs of ARDS (paO2/FIO2 < 150) at the time of admission to ICU. Plasma levels of ELAM1 were measured at 0, 4, 8, 12 hours after admission (TO, T4, T8, T12) and then on ICU days 1,2,3,4 (I)1, D2, D3, D4). Apache II Score, paO2/FIO2 ratio, length of ICU stay and clinical outcome were also calculated. Results are expressed as mean + SD. Student t-test or Mann-Whitney Rank Sum test (where appropriate) were used for statistical analysis, p< 0.05 was considered statistically significant. Results: Of the 13 patients 6 patients subsequently developed ARDS. There were no significant differences in ELAM-1 plasma levels in patients developed ARDS and in those who did not, however initial ELAM-1 plasma levels were insignificantly lower in patients who progressed to ARDS. Results are presented in the table.