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Biomedical subjects

Martin Engström

Publications and source records attributed to Martin Engström.

8 recordsLinked to original sources
PubMed2006

Acidosis impairs the coagulation: A thromboelastographic study.

BACKGROUND: Coagulopathy is a contributor to and predictor of death in bleeding patients. Acidosis is known to be a predictor of worse outcome in trauma patients and to be a coexisting factor in coagulopathic patients, but it has not been studied if it is a causal factor in the development of coagulopathy. METHODS: We have adjusted the pH level in blood samples from healthy volunteers to different levels between 7.4 and 6.8 by the use of hydrochloric acid. Thereafter we have studied the coagulation at the different pH levels by the use of thromboelastography. RESULTS: We found a strong correlation between pH levels and impairment of the coagulation, where the clot strength is increased much slower at pH levels below 7.4 even though the initiation of the clotting seems to be normal. The clot formation time was increased by 168% at pH 6.8 as compared with pH 7.4 (p < 0.00001, r = 0.89) whereas the clotting time was left unaffected. CONCLUSIONS: Acidosis causes a strong impairment of the coagulation as measured with thromboelastography. The impairment found when lowering pH from 7.4 to 7.15 was almost identical to the impairment seen in another study by Kettner et al. when the temperature was lowered from 36 degrees C to 32 degrees C.

Acidosis↗
PubMed2006

Ethanol impairs coagulation and fibrinolysis in whole blood: a study performed with rotational thromboelastometry.

The objective was to study the effects of ethanol on coagulation and fibrinolysis in whole blood. Blood samples from healthy volunteers were analyzed before and after in-vitro addition of ethanol in order to achieve ethanol concentrations of 0, 1, 2 and 4 per thousand, respectively (0, 22, 44 and 88 mmol/l). Coagulation and fibrinolysis were then assessed using rotational thromboelastometry. We found that increasing ethanol levels increasingly impaired coagulation as evaluated with rotational thromboelastometry, with a maximum prolongation of the clot formation time of 118% at an ethanol level of 4 per thousand (P < 0.000001). We also found a very strong impairment of fibrinolysis already at an ethanol level of 1 per thousand. This is the first study assessing the effects of ethanol on coagulation and fibrinolysis in a whole blood model. The impairment of coagulation is similar in nature to the impairment found in patients suffering from hypothermia. The impairment is at a level that may be of clinical importance (e.g. in patients suffering from trauma). The inhibition of fibrinolysis is obvious already at an ethanol level of 1 per thousand and it may be a contributing factor to the increased amount of coronary and cerebrovascular ischemic events after binge drinking.

Alcohol Drinking↗
PubMed2005

An in vitro evaluation of standard rotational thromboelastography in monitoring of effects of recombinant factor VIIa on coagulopathy induced by hydroxy ethyl starch.

BACKGROUND: Rotational thromboelastography (ROTEG) has been proposed as a monitoring tool that can be used to monitor treatment of hemophilia with recombinant factor VIIa (rFVIIa). In these studies special non-standard reagents were used as activators of the coagulation. The aim of this study was to evaluate if standard ROTEG analysis could be used for monitoring of effects of recombinant factor VIIa (rFVIIa) on Hydroxy Ethyl Starch-induced dilutional coagulopathy. METHODS: The study was performed in vitro on healthy volunteers. Prothrombin time (PT) and ROTEG analysis were performed after dilution with 33% hydroxy ethyl starch and also after addition of rFVIIa to the diluted blood. RESULTS: PT was impaired with INR changing from 0.9 before dilution to 1.2 after dilution while addition of rFVIIa to diluted blood lead to an overcorrection of the PT to an International Normalized Ratio (INR) value of 0.6 (p = 0.01). ROTEG activated with the contact activator ellagic acid was impaired by hemodilution (p = 0.01) while addition of rFVIIa had no further effects. ROTEG activated with tissue factor (TF) was also impaired by hemodilution (p = 0.01) while addition of rFVIIa lead to further impairment of the coagulation (p = 0.01). CONCLUSIONS: The parameters affected in the ROTEG analysis were Clot Formation Time and Amplitude after 15 minutes while the Clotting Time was unaffected. We believe these effects to be due to methodological problems when using standard activators of the coagulation in the ROTEG analysis in combination with rFVIIa.

Journal Article↗
PubMed2005

Thrombocytopenia predicts progressive hemorrhage after head trauma.

Patients with traumatic brain injury (TBI) often show progression of hemorrhagic injuries (PHI) after admission to the hospital. This progression is correlated with poor outcome. In this study, we have investigated if thrombocytopenia was a risk factor for PHI. The study was performed on patients admitted to the hospital with severe TBI during year 2000. In total, 50 patients were admitted with severe TBI. Twenty-seven out of these had complete platelet counts at admission and 24 hours thereafter and were included for further study. We found thrombocytopenia at admission to be a risk factor for PHI (p=0.008). We also found that the platelet count decreased more significantly during the first 24 h after injury in patients with PHI compared to patients without PHI (p=0.009). A trend towards longer periods of mechanical ventilation in patients with PHI compared to patients without PHI was identified. These findings support a causal relationship between thrombocytopenia and PHI. The findings provide a rationale for future studies of hemostatic agents in the treatment of TBI in order to minimise complications caused by PHI.

Blood Coagulation Tests↗
PubMed2005

Intracerebral microdialysis in severe brain trauma: the importance of catheter location.

OBJECT: Intracerebral microdialysis has attracted increasing interest as a monitoring technique during neurological/neurosurgical intensive care. The purpose of this study was to compare cerebral energy metabolism, an indicator of secondary excitotoxic injury and cell membrane degradation close to focal traumatic lesions ("penumbra zones") and in remote and apparently intact brain regions of the ipsilateral and contralateral hemispheres. METHODS: The study included 22 consecutive patients with a mean age 44 +/- 17 years and an estimated postresuscitation Glasgow Coma Scale motor score less than 5. Altogether 40 microdialysis catheters with radiopaque tips were inserted. Two catheters could not be localized on postoperative computerized tomography (CT) scans and were excluded from the analysis. The perfusates were analyzed at the patient's bedside for levels of glucose, pyruvate, lactate, glutamate, and glycerol with the aid of a CMA 600 Analyzer. The positions of eight (22%) of the 36 catheters were reclassified after a review of findings on CT scans. Except for pyruvate the values of all biochemical variables and the lactate/pyruvate (L/P) ratio were significantly different in the penumbra zone when compared with mean values found in "normal" tissue ipsilateral to the parenchymal damage and in contralateral normal tissue (p < 0.001). In the penumbra zone a slow normalization of the L/P ratio and levels of glutamate and glycerol were observed. In normal tissue these parameters remained within normal limits. CONCLUSIONS: Data obtained from intracerebral microdialysis can be correctly interpreted only if the locations of the catheters as they relate to focal brain lesions are visualized. A "biochemical penumbra zone" surrounds focal traumatic brain lesions. It remains to be proven whether therapeutic interventions can protect the penumbra zone from permanent damage.

Adult↗
PubMed2002

[NSAID demonstrate convincing effect on postoperative pain].

Non-steroidal antiinflammatory drugs (NSAID) are increasingly being included in the management of postoperative pain as part of a multimodal therapeutic approach. However, there is an ongoing debate among clinicians as to the perioperative use of NSAID's as many authors have cautioned against their use in this setting. Concerns about their impact on coagulation and renal function as well as a risk for gastrointestinal bleeding have been raised. However, many of the adverse effects reported have occurred during long term treatment and might not be directly applicable to the perioperative period. Still the clinician must be aware of the potential risks and benefits of these drugs. This review focuses on the pro's and con's of perioperative NSAID usage. We address the background for a multimodal approach to postoperative pain relief as well as potential alternatives to NSAID's and the recently introduced COX2-selective inhibitors.

Acute Kidney Injury↗