Influence of oxygen therapy on glucose-lactate metabolism after diffuse brain injury

OBJECT: Severe traumatic brain injury (TBI) imposes a huge metabolic load on brain tissue, which can be summarized initially as a state of hypermetabolism and hyperglycolysis. In experiments O2 consumption has been shown to increase early after trauma, especially in the presence of high lactate levels and forced O2 availability. In recent clinical studies the effect of increasing O2 availability on brain metabolism has been analyzed. By their nature, however, clinical trauma models suffer from a heterogeneous injury distribution. The aim of this study was to analyze, in a standardized diffuse brain injury model, the effect of increasing the fraction of inspired O2 on brain glucose and lactate levels, and to compare this effect with the metabolism of the noninjured sham-operated brain. METHODS: A diffuse severe TBI model developed by Foda and Maramarou, et al., in which a 420-g weight is dropped from a height of 2 m was used in this study. Forty-one male Wistar rats each weighing approximately 300 g were included. Anesthesized rats were monitored by placing a femoral arterial line for blood pressure and blood was drawn for a blood gas analysis. Two time periods were defined: Period A was defined as preinjury and Period B as postinjury. During Period B two levels of fraction of inspired oxygen (FiO2) were studied: air (FiO2 0.21) and oxygen (FiO2 1). Four groups were studied including sham-operated animals: air-air-sham (AAS); air-O2-sham (AOS); air-air-trauma (AAT); and air-O2-trauma (AOT). In six rats the effect of increasing the FiO2 on serum glucose and lactate was analyzed. During Period B lactate values in the brain determined using microdialysis were significantly lower (p < 0.05) in the AOT group than in the AAT group and glucose values in the brain determined using microdialysis were significantly higher (p < 0.04). No differences were demonstrated in the other groups. Increasing the FiO2 had no significant effect on the serum levels of glucose and lactate. CONCLUSIONS: Increasing the FiO2 influences dialysate glucose and lactate levels in injured brain tissue. Using an FiO2 of 1 influences brain metabolism in such a way that lactate is significantly reduced and glucose significantly increased. No changes in dialysate glucose and lactate values were found in the noninjured brain.

Severe traumatic brain injury in Switzerland - feasibility and first results of a cohort study

BACKGROUND: We aimed to study the incidence and outcome of severe traumatic brain injury (TBI) in Switzerland and to test the feasibility of a large cohort study with case identification in the first 24 hours and 6-month follow-up. METHODS: From January to June 2005, we consecutively enrolled and followed up all persons with severe TBI (Abbreviated Injury Score of the head region >3 and Glasgow Coma Scale <9) in the catchment areas of 3 Swiss medical centres with neurosurgical facilities. The primary outcome was the Extended Glasgow Outcome Scale (GOSE) after 6 months. Secondary outcomes included survival, Functional Independence Mea - sure (FIM), and health-related quality of life (SF-12) at defined time-points up to 6 months after injury. RESULTS: We recruited 101 participants from a source population of about 2.47 million (ie, about 33% of Swiss population). The incidence of severe TBI was 8.2 per 100,000 person-years. The overall case fatality was 70%: 41 of 101 persons (41%) died at the scene of the accident. 23 of 60 hospitalised participants (38%) died within 48 hours, and 31 (53%) within 6 months. In all hospitalised patients, the median GOSE was 1 (range 1-8) after 6 months, and was 6 (2-8) in 6-month survivors. The median total FIM score was 125 (range 18-126); median-SF-12 component mea - sures were 44 (25-55) for the physical scale and 52 (32-65) for the mental scale. CONCLUSIONS: Severe TBI was associated with high case fatality and considerable morbidity in survivors. We demonstrated the feasibility of a multicentre cohort study in Switzerland with the aim of identifying modifiable determinants of outcome and improving current trauma care.

Long-term outcome of acute spinal cord ischemia syndrome

BACKGROUND AND PURPOSE: Current knowledge of long-term outcome in patients with acute spinal cord ischemia syndrome (ASCIS) is based on few studies with small sample sizes and <2 years' follow-up. Therefore, we analyzed clinical features and outcome of all types of ASCIS to define predictors of recovery. METHODS: From January 1990 through October 2002, 57 patients with ASCIS were admitted to our center. Follow-up data were available for 54. Neurological syndrome and initial degree of impairment were defined according to American Spinal Injury Association (ASIA)/International Medical Society of Paraplegia criteria. Functional outcome was assessed by walking ability and bladder control. RESULTS: Mean age was 59.4 years; 29 were women; and mean follow-up was 4.5 years. The origin was atherosclerosis in 33.3%, aortic pathology in 15.8%, degenerative spine disease in 15.8%, cardiac embolism in 3.5%, systemic hypotension in 1.8%, epidural anesthesia in 1.8%, and cryptogenic in 28%. The initial motor deficit was severe in 30% (ASIA grades A and B), moderate in 28% (ASIA C), and mild in 42% (ASIA D). At follow-up, 41% had regained full walking ability, 30% were able to walk with aids, 20% were wheelchair bound, and 9% had died. Severe initial impairment (ASIA A and B) and female sex were independent predictors of unfavorable outcome (P=0.012 and P=0.043). CONCLUSIONS: Considering a broad spectrum of clinical presentations and origins, the outcome in our study was more favorable than in previous studies reporting on ASCIS subgroups with more severe initial deficits.

Risk of acute kidney injury in patients with severe aortic valve stenosis undergoing transcatheter valve replacement

BACKGROUND: Transcatheter aortic valve implantation (TAVI) for high-risk and inoperable patients with severe aortic stenosis is an emerging procedure in cardiovascular medicine. Little is known of the impact of TAVI on renal function. METHODS: We analysed retrospectively renal baseline characteristics and outcome in 58 patients including 2 patients on chronic haemodialysis undergoing TAVI at our institution. Acute kidney injury (AKI) was defined according to the RIFLE classification. RESULTS: Fifty-eight patients with severe symptomatic aortic stenosis not considered suitable for conventional surgical valve replacement with a mean age of 83 +/- 5 years underwent TAVI. Two patients died during transfemoral valve implantation and two patients in the first month after TAVI resulting in a 30-day mortality of 6.9%. Vascular access was transfemoral in 46 patients and transapical in 12. Estimated glomerular filtration rate (eGFR) increased in 30 patients (56%). Fifteen patients (28%) developed AKI, of which four patients had to be dialyzed temporarily and one remained on chronic renal replacement therapy. Risk factors for AKI comprised, among others, transapical access, number of blood transfusions, postinterventional thrombocytopaenia and severe inflammatory response syndrome (SIRS). CONCLUSIONS: TAVI is feasible in patients with a high burden of comorbidities and in patients with pre-existing end-stage renal disease who would be otherwise not considered as candidates for conventional aortic valve replacement. Although GFR improved in more than half of the patients, this benefit was associated with a risk of postinterventional AKI. Future investigations should define preventive measures of peri-procedural kidney injury.

Does point of care prothrombin time measurement reduce the transfusion of fresh frozen plasma in patients undergoing major surgery? The POC-OP randomized-controlled trial

BACKGROUND: Bleeding is a frequent complication during surgery. The intraoperative administration of blood products, including packed red blood cells, platelets and fresh frozen plasma (FFP), is often live saving. Complications of blood transfusions contribute considerably to perioperative costs and blood product resources are limited. Consequently, strategies to optimize the decision to transfuse are needed. Bleeding during surgery is a dynamic process and may result in major blood loss and coagulopathy due to dilution and consumption. The indication for transfusion should be based on reliable coagulation studies. While hemoglobin levels and platelet counts are available within 15 minutes, standard coagulation studies require one hour. Therefore, the decision to administer FFP has to be made in the absence of any data. Point of care testing of prothrombin time ensures that one major parameter of coagulation is available in the operation theatre within minutes. It is fast, easy to perform, inexpensive and may enable physicians to rationally determine the need for FFP. METHODS/DESIGN: The objective of the POC-OP trial is to determine the effectiveness of point of care prothrombin time testing to reduce the administration of FFP. It is a patient and assessor blind, single center randomized controlled parallel group trial in 220 patients aged between 18 and 90 years undergoing major surgery (any type, except cardiac surgery and liver transplantation) with an estimated blood loss during surgery exceeding 20% of the calculated total blood volume or a requirement of FFP according to the judgment of the physicians in charge. Patients are randomized to usual care plus point of care prothrombin time testing or usual care alone without point of care testing. The primary outcome is the relative risk to receive any FFP perioperatively. The inclusion of 110 patients per group will yield more than 80% power to detect a clinically relevant relative risk of 0.60 to receive FFP of the experimental as compared with the control group. DISCUSSION: Point of care prothrombin time testing in the operation theatre may reduce the administration of FFP considerably, which in turn may decrease costs and complications usually associated with the administration of blood products. TRIAL REGISTRATION: NCT00656396.

Differential influence of arterial blood glucose on cerebral metabolism following severe traumatic brain injury

INTRODUCTION: Maintaining arterial blood glucose within tight limits is beneficial in critically ill patients. Upper and lower limits of detrimental blood glucose levels must be determined. METHODS: In 69 patients with severe traumatic brain injury (TBI), cerebral metabolism was monitored by assessing changes in arterial and jugular venous blood at normocarbia (partial arterial pressure of carbon dioxide (paCO2) 4.4 to 5.6 kPa), normoxia (partial arterial pressure of oxygen (paO2) 9 to 20 kPa), stable haematocrit (27 to 36%), brain temperature 35 to 38 degrees C, and cerebral perfusion pressure (CPP) 70 to 90 mmHg. This resulted in a total of 43,896 values for glucose uptake, lactate release, oxygen extraction ratio (OER), carbon dioxide (CO2) and bicarbonate (HCO3) production, jugular venous oxygen saturation (SjvO2), oxygen-glucose index (OGI), lactate-glucose index (LGI) and lactate-oxygen index (LOI). Arterial blood glucose concentration-dependent influence was determined retrospectively by assessing changes in these parameters within pre-defined blood glucose clusters, ranging from less than 4 to more than 9 mmol/l. RESULTS: Arterial blood glucose significantly influenced signs of cerebral metabolism reflected by increased cerebral glucose uptake, decreased cerebral lactate production, reduced oxygen consumption, negative LGI and decreased cerebral CO2/HCO3 production at arterial blood glucose levels above 6 to 7 mmol/l compared with lower arterial blood glucose concentrations. At blood glucose levels more than 8 mmol/l signs of increased anaerobic glycolysis (OGI less than 6) supervened. CONCLUSIONS: Maintaining arterial blood glucose levels between 6 and 8 mmol/l appears superior compared with lower and higher blood glucose concentrations in terms of stabilised cerebral metabolism. It appears that arterial blood glucose values below 6 and above 8 mmol/l should be avoided. Prospective analysis is required to determine the optimal arterial blood glucose target in patients suffering from severe TBI.

Admission blood glucose is an independent predictive factor for hospital mortality in polytraumatised patients

PURPOSE: The goal of this study was to analyse a possible association of admission blood glucose with hospital mortality of polytraumatised patients and to develop an outcome prediction model for this patient group. METHODS: The outcome of adult polytraumatised patients admitted to the University Hospital of Berne, Switzerland, between 2002 and 2004 with an ISS > or = 17, and more than one severely injured organ system was retrospectively analysed. RESULTS: The inclusion criteria were met by 555 patients, of which 108 (19.5%) died. Hyperglycaemia proved to be an independent predictor for hospital mortality (P < 0.0001), following multiple regression analysis. After inclusion of admission blood glucose, the calculated mortality prediction model performed better than currently described models (P < 0.0001, AUC 0.924). CONCLUSION: In this retrospective, single-centre study in polytraumatised patients, admission blood glucose proved to be an independent predictor of hospital mortality following regression analysis controlling for age, gender, injury severity and other laboratory parameters. A reliable admission blood glucose-based mortality prediction model for polytraumatised patients could be established. This observation may be helpful in improving the precision of future outcome prediction models for polytraumatised patients. These observations warrant further prospective evaluation.

Arterial blood pressure during early sepsis and outcome

OBJECTIVE: To evaluate the association between arterial blood pressure (ABP) during the first 24 h and mortality in sepsis. DESIGN: Retrospective cohort study. SETTING: Multidisciplinary intensive care unit (ICU). PATIENTS AND PARTICIPANTS: A total of 274 septic patients. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Hemodynamic, and laboratory parameters were extracted from a PDMS database. The hourly time integral of ABP drops below clinically relevant systolic arterial pressure (SAP), mean arterial pressure (MAP), and mean perfusion pressure (MPP = MAP - central venous pressure) levels was calculated for the first 24 h after ICU admission and compared with 28-day-mortality. Binary and linear regression models (adjusted for SAPS II as a measure of disease severity), and a receiver operating characteristic (ROC) analysis were applied. The areas under the ROC curve were largest for the hourly time integrals of ABP drops below MAP 60 mmHg (0.779 vs. 0.764 for ABP drops below MAP 55 mmHg; P < or = 0.01) and MPP 45 mmHg. No association between the hourly time integrals of ABP drops below certain SAP levels and mortality was detected. One or more episodes of MAP < 60 mmHg increased the risk of death by 2.96 (CI 95%, 1.06-10.36, P = 0.04). The area under the ROC curve to predict the need for renal replacement therapy was highest for the hourly time integral of ABP drops below MAP 75 mmHg. CONCLUSIONS: A MAP level > or = 60 mmHg may be as safe as higher MAP levels during the first 24 h of ICU therapy in septic patients. A higher MAP may be required to maintain kidney function.

Physical examination during chemoradiation predicts outcome of locally advanced head and neck cancer. Secondary results of a randomized phase III trial (SAKK 10/94)

OBJECTIVES To analyze the prognostic value of clinical tumor response during chemoradiation for locally advanced head and neck cancer. PATIENTS AND METHODS The locoregional response at 50.4Gy was assessed by physical examination (PE) in patients treated within the randomized trial SAKK 10/94 using hyperfractionated radiotherapy (RT), median total dose 74.4Gy with or without cisplatin 20mg/m(2) chemotherapy on 5 consecutive days during weeks 1 and 5 or 6 of RT. Response was classified as a complete response (CR), complete response with uncertainty (Cru), partial response (PR), stable disease (SD), or progressive disease (PD). The primary endpoint was time to treatment failure (TTF) due to any cause. Secondary endpoints included locoregional-recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS) and overall survival (OS). Univariate and multivariate Cox proportional hazards (PH) models were applied to analyze the associations between survival endpoints and clinical tumor response. RESULTS A total of 136, 131 and 97 patients were evaluable for response at the primary tumor, lymph nodes and both sites combined, respectively. At 50.4Gy 57/136 (42%), 46/131 (35%) and 21/97 (22%) patients had a good response (CR/Cru vs. PR/SD) at the primary tumor, the lymph nodes, and both sites combined, respectively. The median follow-up times were 11.4, 9.6 and 11.4years for the three groups. Good responses were all significantly associated with improved TTF, LRRFS, DMFS and OS in univariate analysis whereas good response at the primary tumor and lymph nodes remained significantly associated with TTF and OS after multivariate Cox PH models. CONCLUSIONS Locoregional response at 50.4Gy was identified as predictor of oncologic outcome. PE during treatment should not be underestimated in clinical practice.

Taxane-containing induction chemotherapy followed by definitive chemoradiotherapy. Outcome in patients with locally advanced head and neck cancer

BACKGROUND Induction chemotherapy followed by definitive chemoradiotherapy is an intensified treatment approach for locally advanced squamous cell carcinoma of the head and neck (HNSCC) that might be associated with high rates of toxicity. MATERIALS AND METHODS The data of 40 consecutive patients who underwent induction chemotherapy with docetaxel-containing regimens followed by intensity-modulated radiotherapy (IMRT) and concomitant systemic therapy for unresectable locally advanced HNSCC were retrospectively analyzed. Primary objectives were RT-related acute and late toxicity. Secondary objectives were response to induction chemotherapy, locoregional recurrence-free survival (LRRFS), overall survival (OS), and influencing factors for LRRFS and OS. RESULTS The median follow-up for surviving patients was 21 months (range, 2-53 months). Patients received a median of three cycles of induction chemotherapy followed by IMRT to 72 Gy. Three patients died during induction chemotherapy and one during chemoradiotherapy. Acute RT-related toxicity was of grade 3 and 4 in 72 and 3 % of patients, respectively, mainly dysphagia and dermatitis. Late RT-related toxicity was mainly xerostomia and bone/cartilage necrosis and was of grade 3 and 4 in 15 % of patients. One- and 2-year LRRFS and OS were 72 and 49 % and 77 and 71 %, respectively. CONCLUSION Induction chemotherapy followed by chemoradiotherapy using IMRT was associated with a high rate of severe acute and late RT-related toxicities in this selected patient cohort. Four patients were lost because of fatal complications. Induction chemotherapy did not compromise the delivery of full-dose RT; however, the use of three cycles of concomitant cisplatin was impaired.

Correlations between severity of clinical signs and histopathological changes in 60 dogs with spinal cord injury associated with acute thoracolumbar intervertebral disc disease

The outcome of spinal surgery in dogs with absent voluntary motor function and nociception following intervertebral disc (IVD) herniation is highly variable, which likely attests to differences in the severity of spinal cord damage. This retrospective study evaluated the extent to which neurological signs correlated with histologically detected spinal cord damage in 60 dogs that were euthanased because of thoracolumbar IVD herniation. Clinical neurological grades correlated significantly with the extent of white matter damage (P<0.001). However, loss of nociception also occurred in 6/31 (19%) dogs with relatively mild histological changes. The duration of clinical signs, Schiff-Sherrington posture, loss of reflexes and pain on spinal palpation were not significantly associated with the severity of spinal cord damage. Although clinical-pathological correlation was generally good, some clinical signs frequently thought to indicate severe cord injury did not always correlate with the degree of cord damage, suggesting functional rather than structural impairment in some cases.

Does single use of an autologous transfusion system in TKA reduce the need for allogenic blood?: a prospective randomized trial

BACKGROUND Mechanical autotransfusion systems for washed shed blood (WSB) were introduced to reduce the need for postoperative allogenic blood transfusions (ABTs). Although some authors have postulated decreased requirements for ABT by using autologous retransfusion devices, other trials, mostly evaluating retransfusion devices for unwashed shed blood (USB), verified a small or no benefit in reducing the need for postoperative ABT. Because of these contradictory findings it is still unclear whether autologous retransfusion systems for WSB can reduce transfusion requirements. QUESTIONS/PURPOSES We therefore asked whether one such autologous transfusion system for WSB can reduce the requirements for postoperative ABT. METHODS In a prospective, randomized, controlled study, we enrolled 151 patients undergoing TKA. In Group A (n=76 patients), the autotransfusion system was used for a total of 6 hours (intraoperatively and postoperatively) and the WSB was retransfused after processing. In Control Group B (n=75 patients), a regular drain without suction was used. We used signs of anemia and/or a hemoglobin value less than 8 g/dL as indications for transfusion. If necessary, we administered one or two units of allogenic blood. RESULTS Twenty-three patients (33%) in Group A, who received an average of 283 mL (range, 160-406 mL) of salvaged blood, needed a mean of 2.1 units of allogenic blood, compared with 23 patients (33%) in Control Group B who needed a mean of 2.1 units of allogenic blood. CONCLUSIONS We found the use of an autotransfusion system did not reduce the rate of postoperative ABTs. LEVEL OF EVIDENCE Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Surgery for low-grade glioma infiltrating the central cerebral region: location as a predictive factor for neurological deficit, epileptological outcome, and quality of life

OBJECT A main concern with regard to surgery for low-grade glioma (LGG, WHO Grade II) is maintenance of the patient's functional integrity. This concern is particularly relevant for gliomas in the central region, where damage can have grave repercussions. The authors evaluated postsurgical outcomes with regard to neurological deficits, seizures, and quality of life. METHODS Outcomes were compared for 33 patients with central LGG (central cohort) and a control cohort of 31 patients with frontal LGG (frontal cohort), all of whom had had medically intractable seizures before undergoing surgery with mapping while awake. All surgeries were performed in the period from February 2007 through April 2010 at the same institution. RESULTS For the central cohort, the median extent of resection was 92% (range 80%-97%), and for the frontal cohort, the median extent of resection was 93% (range 83%-98%; p = 1.0). Although the rate of mild neurological deficits was similar for both groups, seizure freedom (Engel Class I) was achieved for only 4 (12.1%) of 33 patients in the central cohort compared with 26 (83.9%) of 31 patients in the frontal cohort (p < 0.0001). The rate of return to work was lower for patients in the central cohort (4 [12.1%] of 33) than for the patients in the frontal cohort (28 [90.3%] of 31; p < 0.0001). CONCLUSIONS Resection of central LGG is feasible and safe when appropriate intraoperative mapping is used. However, seizure control for these patients remains poor, a finding that contrasts markedly with seizure control for patients in the frontal cohort and with that reported in the literature. For patients with central LGG, poor seizure control ultimately determines quality of life because most will not be able to return to work.

Analysis of Pressure Head-Flow Loops of Pulsatile Rotodynamic Blood Pumps

The clinical importance of pulsatility is a recurring topic of debate in mechanical circulatory support. Lack of pulsatility has been identified as a possible factor responsible for adverse events and has also demonstrated a role in myocardial perfusion and cardiac recovery. A commonly used method for restoring pulsatility with rotodynamic blood pumps (RBPs) is to modulate the speed profile, synchronized to the cardiac cycle. This introduces additional parameters that influence the (un)loading of the heart, including the timing (phase shift) between the native cardiac cycle and the pump pulses, and the amplitude of speed modulation. In this study, the impact of these parameters upon the heart-RBP interaction was examined in terms of the pressure head-flow (HQ) diagram. The measurements were conducted using a rotodynamic Deltastream DP2 pump in a validated hybrid mock circulation with baroreflex function. The pump was operated with a sinusoidal speed profile, synchronized to the native cardiac cycle. The simulated ventriculo-aortic cannulation showed that the level of (un)loading and the shape of the HQ loops strongly depend on the phase shift. The HQ loops displayed characteristic shapes depending on the phase shift. Increased contribution of native contraction (increased ventricular stroke work [WS ]) resulted in a broadening of the loops. It was found that the previously described linear relationship between WS and the area of the HQ loop for constant pump speeds becomes a family of linear relationships, whose slope depends on the phase shift.