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Biomedical subjects

Jens Soukup

Publications and source records attributed to Jens Soukup.

11 recordsLinked to original sources

Efficiency of 7.2% hypertonic saline hydroxyethyl starch 200/0.5 versus mannitol 15% in the treatment of increased intracranial pressure in neurosurgical patients - a randomized clinical trial [ISRCTN62699180].

INTRODUCTION: This prospective randomized clinical study investigated the efficacy and safety of 7.2% hypertonic saline hydroxyethyl starch 200/0.5 (7.2% NaCl/HES 200/0.5) in comparison with 15% mannitol in the treatment of increased intracranial pressure (ICP). METHODS: Forty neurosurgical patients at risk of increased ICP were randomized to receive either 7.2% NaCl/HES 200/0.5 or 15% mannitol at a defined infusion rate, which was stopped when ICP was < 15 mmHg. RESULTS: Of the 40 patients, 17 patients received 7.2% NaCl/HES 200/0.5 and 15 received mannitol 15%. In eight patients, ICP did not exceed 20 mmHg so treatment was not necessary. Both drugs decreased ICP below 15 mmHg (p < 0.0001); 7.2% NaCl/HES 200/0.5 within 6.0 (1.2-15.0) min (all results are presented as median (minimum-maximum range)) and mannitol within 8.7 (4.2-19.9) min (p < 0.0002). 7.2% NaCl/HES 200/0.5 caused a greater decrease in ICP than mannitol (57% vs 48%; p < 0.01). The cerebral perfusion pressure was increased from 60 (39-78) mmHg to 72 (54-85) mmHg by infusion with 7.2% NaCl/HES 200/0.5 (p < 0.0001) and from 61 (47-71) mmHg to 70 (50-79) mmHg with mannitol (p < 0.0001). The mean arterial pressure was increased by 3.7% during the infusion of 7.2% NaCl/HES 200/0.5 but was not altered by mannitol. There were no clinically relevant effects on electrolyte concentrations and osmolarity in the blood. The mean effective dose to achieve an ICP below 15 mmHg was 1.4 (0.3-3.1) ml/kg for 7.2% NaCl/HES 200/0.5 and 1.8 (0.45-6.5) ml/kg for mannitol (p < 0.05). CONCLUSION: 7.2% NaCl/HES 200/0.5 is more effective than mannitol 15% in the treatment of increased ICP. A dose of 1.4 ml/kg of 7.2% NaCl/HES 200/0.5 can be recommended as effective and safe. The advantage of 7.2% NaCl/HES 200/0.5 might be explained by local osmotic effects, because there were no clinically relevant differences in hemodynamic clinical chemistry parameters.

Adult↗

Skin function parameters in intensive-care patients.

BACKGROUND/PURPOSE: The study was performed to investigate the transepidermal water loss (TEWL) and pH-value in patients in intensive care. METHODS: Forty intensive-care patients (22 men, 18 women) were included in the study. TEWL and pH-values were measured at admission, and after 24, 96 and 168 h. The areas of measurement were the forehead, the volar forearm, paraumbilical and the ventral thigh. The measurements were made under standardized environmental conditions according to the recommendations of the EMCO Group. RESULTS: Elevated values were found on the forehead compared with the other skin areas examined. There was no significant change in mean TEWL-values in any patient in the course of the study. There was also no significant influence of TEWL at the time of admission on the prognosis. The course analysis of the mean pH-values, however, showed that patients who developed a systemic inflammatory response syndrome (SIRS) or sepsis during the further course had a higher pH-value over the entire study period. CONCLUSION: TEWL and the pH of the skin surface could be measured at bedside in the intensive-care unit and delivered reproducible results. These parameters appear, however, to be relevant only for subgroups of patients under intensive care.

Critical Care↗

Cerebral acid-base homeostasis after severe traumatic brain injury.

OBJECT: Brain tissue acidosis is known to mediate neuronal death. Therefore the authors measured the main parameters of cerebral acid-base homeostasis, as well as their interrelations, shortly after severe traumatic brain injury (TBI) in humans. METHODS: Brain tissue pH, PCO2, PO2, and/or lactate were measured in 151 patients with severe head injuries, by using a Neurotrend sensor and/or a microdialysis probe. Monitoring was started as soon as possible after the injury and continued for up to 4 days. During the 1st day following the trauma, the brain tissue pH was significantly lower, compared with later time points, in patients who died or remained in a persistent vegetative state. Six hours after the injury, brain tissue PCO2 was significantly higher in patients with a poor outcome compared with patients with a good outcome. Furthermore, significant elevations in cerebral concentrations of lactate were found during the 1st day after the injury, compared with later time points. These increases in lactate were typically more pronounced in patients with a poor outcome. Similar biochemical changes were observed during later hypoxic events. CONCLUSIONS: Severe human TBI profoundly disturbs cerebral acid-base homeostasis. The observed pH changes persist for the first 24 hours after the trauma. Brain tissue acidosis is associated with increased tissue PCO2 and lactate concentration; these pathobiochemical changes are more severe in patients who remain in a persistent vegetative state or die. Furthermore, increased brain tissue PCO2 (> 60 mm Hg) appears to be a useful clinical indicator of critical cerebral ischemia, especially when accompanied by increased lactate concentrations.

Acid-Base Equilibrium↗

Influence of moderate and profound hyperventilation on cerebral blood flow, oxygenation and metabolism.

OBJECTIVE: The aim of the present study was to examine the impact of moderate and profound hyperventilation on regional cerebral blood flow (rCBF), oxygenation and metabolism. MATERIALS AND METHODS: Twelve anesthetized pigs were subjected to moderate (mHV) and profound (pHV) hyperventilation (target arterial pO(2): 30 and 20 mmHg, respectively) for 30 min each, after baseline normoventilation (BL) for 1 h. Local cerebral extracellular fluid (ECF) concentrations of glucose, lactate, pyruvate and glutamate as well as brain tissue oxygenation (p(ti)O(2)) were monitored using microdialysis and a Licox oxygen sensor, respectively. In nine pigs, regional cerebral blood flow (rCBF) was also continuously measured via a thermal diffusion system. RESULTS: Both moderate and profound hyperventilation resulted in a significant decrease in rCBF (BL: 37.9+/-4.3 ml/100 g/min; mHV: 29.4+/-3.6 ml/100 g/min; pHV: 23.6+/-4.7 ml/100 g/min; p<0.05) and p(ti)O(2) (BL: 22.7+/-4.1 mmHg; mHV: 18.9+/-4.9 mmHg; pHV: 13.0+/-2.2 mmHg; p<0.05). A p(ti)O(2) decrease below the critical threshold of 10 mmHg was induced in three animals by moderate hyperventilation and in five animals by profound hyperventilation. Furthermore, significant increases in lactate (BL: 1.06+/-0.18 mmol/l; mHV: 1.36+/-0.20 mmol/l; pHV: 1.67+/-0.17 mmol/l; p<0.005), pyruvate (BL: 46.4+/-7.8 micromol/l; mHV: 58.0+/-10.3 micromol/l; pHV: 66.1+/-12.7 micromol/l; p<0.05), and lactate/glucose ratio were observed during hyperventilation. (Data are presented as mean+/-S.E.M.) CONCLUSIONS: Both moderate and profound hyperventilation may result in insufficient regional oxygen supply and anaerobic metabolism, even in the uninjured brain. Therefore, the use of hyperventilation cannot be considered as a safe procedure and should either be avoided or used with extreme caution.

Animals↗

Safety and efficacy of analgesia-based sedation with remifentanil versus standard hypnotic-based regimens in intensive care unit patients with brain injuries: a randomised, controlled trial [ISRCTN50308308].

INTRODUCTION: This randomised, open-label, observational, multicentre, parallel group study assessed the safety and efficacy of analgesia-based sedation using remifentanil in the neuro-intensive care unit. METHODS: Patients aged 18-80 years admitted to the intensive care unit within the previous 24 hours, with acute brain injury or after neurosurgery, intubated, expected to require mechanical ventilation for 1-5 days and requiring daily downward titration of sedation for assessment of neurological function were studied. Patients received one of two treatment regimens. Regimen one consisted of analgesia-based sedation, in which remifentanil (initial rate 9 microg kg(-1) h(-1)) was titrated before the addition of a hypnotic agent (propofol [0.5 mg kg(-1) h(-1)] during days 1-3, midazolam [0.03 mg kg(-1) h(-1)] during days 4 and 5) (n = 84). Regimen two consisted of hypnotic-based sedation: hypnotic agent (propofol days 1-3; midazolam days 4 and 5) and fentanyl (n = 37) or morphine (n = 40) according to routine clinical practice. For each regimen, agents were titrated to achieve optimal sedation (Sedation-Agitation Scale score 1-3) and analgesia (Pain Intensity score 1-2). RESULTS: Overall, between-patient variability around the time of neurological assessment was statistically significantly smaller when using remifentanil (remifentanil 0.44 versus fentanyl 0.86 [P = 0.024] versus morphine 0.98 [P = 0.006]. Overall, mean neurological assessment times were significantly shorter when using remifentanil (remifentanil 0.41 hour versus fentanyl 0.71 hour [P = 0.001] versus morphine 0.82 hour [P < 0.001]). Patients receiving the remifentanil-based regimen were extubated significantly faster than those treated with morphine (1.0 hour versus 1.93 hour, P = 0.001) but there was no difference between remifentanil and fentanyl. Remifentanil was effective, well tolerated and provided comparable haemodynamic stability to that of the hypnotic-based regimen. Over three times as many users rated analgesia-based sedation with remifentanil as very good or excellent in facilitating assessment of neurological function compared with the hypnotic-based regimen. CONCLUSIONS: Analgesia-based sedation with remifentanil permitted significantly faster and more predictable awakening for neurological assessment. Analgesia-based sedation with remifentanil was very effective, well tolerated and had a similar adverse event and haemodynamic profile to those of hypnotic-based regimens when used in critically ill neuro-intensive care unit patients for up to 5 days.

Adjuvants, Anesthesia↗

Experiences with continuous intra-arterial blood gas monitoring: precision and drift of a pure optode-system.

OBJECTIVE: The utility of continuous intra-arterial blood gas analysis (CBGA) with combined electrochemical and optode sensors has been demonstrated. More recently, a pure optode sensor with a changed sensing element architecture has become available. The aim was to determine the measurement accuracy and long-term stability of the new sensor. DESIGN: A prospective explorative study was performed. Simultaneous measurements of intermittent blood gas analyses (IBGA) (ABL 610, Radiometer, Copenhagen) and CBGA (Diametrics Medical, High Wycombe, Bucks., UK) were compared using Bland-Altman analysis. PATIENTS: Twenty-five patients admitted to the ICU and requiring mechanical ventilation for an expected minimum of about 96 h were included. RESULTS: Mean monitoring time was 106.1 (range 15-231) hours. Bias and precision for PO(2 )were -0.2 kPa (1%)+/-1.8 kPa (9.5%); PCO(2): 0.03 kPa (0.6%)+/-0.44 kPa (9.3%); pH: -0.001 (0.01%)+/-0.04 (0.45%). The sensor showed no change of measurement characteristics during 4 days of measurement. However, in 69 cases continuous monitoring was interrupted (reversible sudden drops of PO(2) measurement) possibly caused by thrombotic deposition and/or sensor bending and accidental sensor retraction. CONCLUSIONS: The precision and bias of the PCO(2)- and pH-sensing elements were in line with the findings of the older sensor technology. The possibility that the PO(2) optode could offer greater accuracy than the older technology is suggested by comparisons with results reported in previous studies. No sensor drift occurred during long-term measurement over more than 4 days.

Adult↗

Analysis and treatment of different types of neuropathic cancer pain.

Neuropathic pain is a major problem in the treatment of cancer pain. We performed a retrospective analysis of 213 cancer patients with neuropathic pain treated by a pain service following the World Health Organization guidelines for relief of cancer pain. Of these, 79% presented with nerve compression pain, 16% with nerve injury pain, and 5% with sympathetically-maintained pain. Whereas nerve compression and nerve injury pain were caused most frequently by cancer growth, sympathetically-maintained pain was caused most frequently by cancer treatment. There were no significant differences in the use of analgesics, the mean pain intensity, or the efficacy of analgesic treatment among the three groups. Nerve injury pain and sympathetically-maintained pain were treated more frequently with adjuvant analgesics, especially antidepressants and anticonvulsants. The variety of different neuropathic pain syndromes should be separated in future studies of the efficacy of different treatment approaches.

Adult↗

The importance of brain temperature in patients after severe head injury: relationship to intracranial pressure, cerebral perfusion pressure, cerebral blood flow, and outcome.

Brain temperature was continuously measured in 58 patients after severe head injury and compared to rectal temperature, intracranial pressure, cerebral blood flow, and outcome after 3 months. The temperature difference between brain and rectal temperature was also calculated. Mild hypothermia (34-36 degrees C) was also used to treat uncontrollable intracranial pressure (ICP) above 20 mm Hg when other methods failed. Brain and rectal temperature were strongly correlated (r = 0.866; p < 0.001). Four groups were identified. The mean brain temperature ranged from 36.9 +/- 0.4 degrees C in the normothermic group to 38.2 +/- 0.5 degrees C in the hyperthermic group, 35.3 +/- 0.5 degrees C in the mild therapeutic hypothermia group, and 34.3 +/- 1.5 degrees C in the hypothermia group without active cooling. The mean DeltaT(br-rect) was positive for patients with a T(br) above 36.0 degrees C (0.0 +/- 0.5 degrees C) and negative for patients during mild therapeutic hypothermia (-0.2 +/- 0.6 degrees C) and also in those with a brain temperature below 36 degrees C without active cooling (0.8 +/- -1.4 degrees C) - the spontaneous hypothermic group. The cerebral perfusion pressure (CPP) was increased significantly by active cooling compared to the normothermic and hyperthermic groups. The mean cerebral blood flow (CBF) in patients with a brain temperature between 36.0 degrees C and 37.5 degrees C was 37.8 +/- 14.0 mL/100 g/min. The lowest CBF was measured in patients with a brain temperature <36.0 degrees C and a negative brain-rectal temperature difference (17.1 +/- 14.0 mL/100 g/min). A positive trend for improved outcome was seen in patients with mild hypothermia. Simultaneous monitoring of brain and rectal temperature provides important diagnostic and prognostic information to guide the treatment of patients after severe head injury (SHI) and the wide differentials that can develop between the brain and core temperature, especially during rapid cooling, strongly supports the use of brain temperature measurement if therapeutic hypothermia is considered for head injury care.

Adolescent↗

Relationship between brain temperature, brain chemistry and oxygen delivery after severe human head injury: the effect of mild hypothermia.

We studied brain temperature and the effect of mild hypothermia in 58 patients after severe head injury (SHI). Brain tissue oxygen tension (ptiO2), carbon dioxide tension (ptiCO2), tissuie pH (pHti) and temperature (T.br) were measured using a multiparameter probe. Microdialysis was performed to measure glucose, lactate, glutamate, and aspartate in the extracellular fluid. Mild hypothermia (34 degrees-36 degrees C) was employed in 33 selected patients who had persistent increased intracranial pressure (ICP > 20 mmHg). Mild induced hypothermia decreased brain oxygen significantly from 33 +/- 24 mmHg to 30 +/- 22 mmHg (p < 0.05). The ptiCO2 (46 +/- 8 mmHg) was also significantly lower during mild hypothermia (40.4 +/- 4.0 mmHg), p < 0.0001). The pHti increased from 7.13 +/- 0.15 to 7.24 +/- 0.10 (p < 0.0001) under hypothermic conditions. Induced hypothermia may protect patients from secondary ischemic events by lowering the critical ptiO2 threshold, reducing anaerobic metabolism, and decreasing the release of excitatory aminoacids. However, patients with spontaneous brain hypothermia on admission (Tbr < 36.0 degrees C) showed significantly higher levels of glutamate as well as lactate, compared to all other patients, and had a worse outcome. Spontaneous brain hypothermia carries a poor prognosis, and was characterized by markedly abnormal brain metabolic indices.

Adolescent↗