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Biomedical subjects

J Piek

Publications and source records attributed to J Piek.

At least 37 records · Page 2Linked to original sources
PubMed1998

Transcranial power mode Doppler duplex sonography of intracranial aneurysms.

The application of different color-coding techniques in transcranial color-coded duplex sonography (TCCD) was assessed for detection and measurement of the size of intracranial aneurysms. Thirty-two consecutively examined patients with 36 angiographically verified cerebral aneurysms underwent TCCD with color Doppler flow imaging (CDFI), power Doppler imaging (PDI), and both methods with contrast enhancement. The diameters of the aneurysms were measured in comparable planes by means of angiography and TCCD-PD with and without 400 mg/ml of the monosaccharide microparticle contrast agent Levovist. TCCD with CFD enabled detection of 27 of 36 aneurysms (75%), and PD depicted 29 aneurysms (80%). After administration of Levovist, an additional two aneurysms were detected with CFD and three with PD color coding. Measurements of aneurysm size obtained by means of PD with contrast enhancement corresponded more highly with angiographic findings than did measurements obtained with PD alone. Use of alternative color-coding techniques with the addition of contrast agents increases the number of intracranial nonthrombosed aneurysms detectable with TCCD.

Adolescent↗
PubMed1998

A multicenter trial on the efficacy of using tirilazad mesylate in cases of head injury.

OBJECT: The authors prospectively studied the efficacy of tirilazad mesylate, a novel aminosteroid, in humans with head injuries. METHODS: A cohort of 1120 head-injured patients received at least one dose of study medication (tirilazad or placebo). Eighty-five percent (957) of the patients had suffered a severe head injury (Glasgow Coma Scale [GCS] score 4-8) and 15% (163) had sustained a moderate head injury (GCS score 9-12). Six-month outcomes for the tirilazad- and placebo-treated groups for the Glasgow Outcome Scale categories of both good recovery and death showed no significant difference (good recovery in the tirilazad-treated group was 39% compared with the placebo group in which it was 42% [p=0.461]; death in the tirilazad-treated group occurred in 26% of patients compared with the placebo group, in which it occurred in 25% [p=0.750]). Subgroup analysis suggested that tirilazad mesylate may be effective in reducing mortality rates in males suffering from severe head injury with accompanying traumatic subarachnoid hemorrhage (death in the tirilazad-treated group occurred in 34% of patients; in the placebo group it occurred in 43% [p=0.026]). No significant differences in frequency or types of serious adverse events were shown between the treatment and placebo groups. CONCLUSIONS: Striking problems with imbalance concerning basic prognostic variables were observed in spite of the large population studied. These imbalances concerned pretreatment hypotension, pretreatment hypoxia, and the incidence of epidural hematomas. In future trials of pharmacological therapy for severe head injury, serious consideration must be given to alternative randomization strategies. Given the heterogeneous nature of head injury and the identification of populations that do relatively well with standard therapy, target populations with a higher risk for mortality and morbidity may be more suitable for clinical trials of such agents.

Adult↗
PubMed1998

Waterjet dissection of the brain: experimental and first clinical results. Technical note.

Control of bleeding during dissection is a problem that is still not completely resolved in neurosurgical procedures. To overcome this problem in some settings, the authors, in close collaboration with their institution, developed a new device for blunt dissection of brain tumors that is based on a waterjet technique. This report describes their first experimental and clinical experience with this new method. Numerous cutting experiments were performed in porcine cadaver brains. The best results were obtained using pressures from 4 to 6 bars with a 100-microm tip, which produced very small, precise cuts. Histological evaluation showed no disruption or vacuolization of the surrounding tissue. The authors have used the new device in nine patients (seven with gliomas and two undergoing temporal lobe resections for epilepsy), and no complications have been observed. The waterjet device allowed dissection of the brain tissue while even small exposed vessels were spared injury. The instrument was found to be easy to use. Future investigations will concentrate on adapting this new method to endoscopic surgery and evaluating fluids with low surface tension to avoid foaming and bubbling during open surgery.

Animals↗
PubMed1998

[Prepontine epidural hemorrhage].

Extradural haematomas of the clivus represent a rare event and occur almost only in infancy. The case of a haematoma promptly operated upon via a transdural cerebellopontine angle approach is described for the first time. The mechanism of injury is discussed.

Child↗
PubMed1997

Prognostic value of intracoronary flow velocity and diameter stenosis in assessing the short- and long-term outcomes of coronary balloon angioplasty: the DEBATE Study (Doppler Endpoints Balloon Angioplasty Trial Europe).

BACKGROUND: The aim of this prospective, multicenter study was the identification of Doppler flow velocity measurements predictive of clinical outcome of patients undergoing single-vessel balloon angioplasty with no previous Q-wave myocardial infarction. METHODS AND RESULTS: In 297 patients, a Doppler guidewire was used to measure basal and maximal hyperemic flow velocities proximal and distal to the stenosis before and after angioplasty. In 225 patients with an angiographically successful percutaneous transluminal coronary angioplasty (PTCA), postprocedural distal coronary flow reserve (CFR) and percent diameter stenosis (DS%) were correlated with symptoms and/or ischemia at 1 and 6 months, with the need for target lesion revascularization, and with angiographic restenosis (defined as DS > or = 50% at follow-up). Logistic regression and receiver operator characteristic curve analyses were applied to determine the prognostic cutoff value of CFR and DS separately and in combination. Optimal cutoff criteria for predictors of these clinical events were DS, 35%; CFR, 2.5. A distal CFR after angioplasty > 2.5 with a residual DS < or = 35% identified lesions with a low incidence of recurrence of symptoms at 1 month (10% versus 19%, P=.149) and at 6 months (23% versus 47%, P=.005), a low need for reintervention (16% versus 34%, P=.024), and a low restenosis rate (16% versus 41%, P=.002) compared with patients who did not meet these criteria. CONCLUSIONS: Measurements of distal CFR after PTCA, in combination with DS%, have a predictive value, albeit modest for the short- and long-term outcomes after PTCA, and thus may be used to identify patients who will or will not benefit from additional therapy such as stent implantation.

Aged↗
PubMed1997

Ictal and interictal ECD-SPECT for focus localization in epilepsy.

Forty-one ECD (Technetium-99m-ethyl cysteinate dimer) SPECT investigations were undertaken in the course of a presurgical diagnostic work-up in 23 patients with pharmacoresistant focal epilepsy. In 21 patients, both an ictal and interictal SPECT were conducted. In the patients receiving ictal SPECT the tracer was injected between 7 and 30 s after the seizure onset. Of the interictal SPECTs 17 of 23 showed focal hypoperfusion which was consistent in 17 cases (74%) with the area of the electrophysiological focus (EF) and 6 patients had a normal interictal SPECT. Of the ictal SPECTs 18 of 21 (86%) showed regional hyperperfusion, 18 of them in the same location as the EF. Ictal SPECT showed a hypoperfusion similar to that in interictal SPECT in another 3 patients. In these cases seizure duration was short (28-54 s), so that the tracer reached the brain postictally. Our results show that ictal ECD-SPECT is an effective method for demonstrating an epileptogenic focus. Possible reasons for false-negative ictal SPECT results are discussed.

Adolescent↗
PubMed1997

[A simple technique for reconstruction of anterior and middle cranial base after palliative tumor resection].

Large defects of the anterior and middle skull base resulting from extensive tumour resection should be reconstructed. Reconstruction should not only include watertight closure of the dura but also osseous reconstruction. Numerous alloplastic and autoplastic grafts have been used for this purpose. Following curative tumour resection autoplastic material is used at our institution. Autoplastic bone/however requires additional procedures, adds additional operating time, and often requires surgical recontouring because of its rigidity. Therefore we have used a simplified technique using autologous grafts for dural repair in combination with a Vitallium mesh for osseous reconstruction after palliative tumour surgery. So far this technique has been used in 10 patients with different malignancies of the anterior and middle skull base. No complications with the implant was observed. There was no operative mortality and morbidity. One postoperative meningitis was cured by antibiotics. Compared to autogenous bone the technique saved operating time, had more intraoperative flexibility, and a low complication rate with good cosmetic results.

Adult↗
PubMed1996

Pressure-controlled drainage of cerebrospinal fluid: clinical experience with a new type of ventricular catheter (Ventcontrol MTC)and an integrated Piezo-resistive sensor at its tip: technical note.

We described a new ventricular catheter that is the combination of a "classic" ventricular catheter with a piezo-resistive transducer at its tip. The device allows parallel recordings of intraventricular fluid pressure via a chip and a fluid-filled external transducer, drainage of cerebrospinal fluid from the ventricle or injection of fluid into the ventricle with simultaneous monitoring of intracranial pressure, and recording of brain tissue pressure in cases of misplacement or dislocation of the ventricular catheter or in cases of progressively narrowing ventricles caused by brain edema. Clinical tests in various situations at different pressure ranges (total recording time, 1356 h in 13 patients) gave excellent correlations of both pressures. Application of the device is especially indicated in clinical situations in which pressure-controlled drainage is desirable, occlusion of ventricular bolts is likely, or pressure-volume tests are needed.

Brain Edema↗
PubMed1995

The effects of alcohol on preparation for expected and unexpected events.

The present paper is concerned with investigating the effects of alcohol in situations where unexpected events occur and responses need to be cancelled and reprogrammed. One experiment is reported which involved the modification of an eight-choice reaction-time task, employing the priming procedures of Posner to investigate the effects of alcohol on decision times to expected and unexpected events. The experiment involved a series of valid pre-cues in which accurate information was provided about the up-coming response, and a series of invalid pre-cues in which the "wrong" information was given to subjects. The effects of alcohol (0.09% BAC) was significant on the invalid trials, in which reaction time slowed significantly and error rates increased significantly. The results are discussed in terms of response processing and attention-switching.

Journal Article↗
PubMed1995

Medical complications in severe head injury.

Virtually any medical complication can occur during the post-traumatic course of an individual patient with a severe head injury (SHI). Although recovery of an individual patient can be adversely influenced by any of these medical complications, only a few selected complications have been proven to be independent predictors of an unfavorable outcome. The most frequent medical complications in SHI patients include disturbances of serum electrolytes (60%) and blood coagulation (18%), pneumonia (40%), and septicemia (10%). Hypotension is also common, occurring both prehospital and inhospital at a frequency of 29% and 22%, respectively. These factors are statistically independent predictors of poor outcome in SHI patients. It has been suggested that elimination of these frequent complications might result in a 7.5% reduction of unfavorable outcome in this patient group.

Blood Coagulation Disorders↗
PubMed1994

"Ultrahigh" dexamethasone in acute brain injury. Results from a prospective randomized double-blind multicenter trial (GUDHIS). German Ultrahigh Dexamethasone Head Injury Study Group.

In a prospective randomized double-blind multicenter trial, the efficacy and safety of a 51-hour ultra-high intravenous dexamethasone dosing regimen was investigated in patients with moderate and severe head injury. 300 patients between 15 and 55 years of age were randomized to receive either placebo or dexamethasone: 500 mg intravenous infusion within 3 h after trauma initially, followed by 200 mg after 3 h, thereafter 8 times 200 mg at 6 hourly intervals, resulting in a total administered dose of 2,3 g in 51 hours. Primary end points for assessment of efficacy were: Modified Glasgow Coma Scale (grading 3-16) on Day 5, modified Glasgow Outcome Scale (grading 1-6) 10-14 months after injury, and the time interval until consciousness improved above a level of modified GCS > or = 8. Secondary endpoints were CT results and neurological and laboratory data. The two groups were well matched with respect to important prognostic variables, such as age, severity of trauma, and interval between trauma and application of the drug. 269 patients (89.7%) were available for final examination after 10-14 months. Results were surprisingly favourable in both groups: Lethality in the dexamethasone and placebo group was 14.3 and 15.4%, respectively, and 61.7 and 57.4%, respectively, achieved social and professional rehabilitation after 10-14 months (outcome scale 6). No statistical difference was seen between the dexamethasone and the placebo group in any of the primary end points of efficacy and safety (incidence of upper gastrointestinal bleeding, infection, and thrombosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Complications in measuring ventricular pressure in patients with craniocerebral trauma and spontaneous intracranial hemorrhage--a prospective study].

Complications of continuous registration of intracranial pressure were studied prospectively over a 2 year period in two groups of patients with head injuries (HI) and spontaneous intracranial haemorrhages (ICH). 53 patients of total 234 patients with head injuries and 68 patients of total 185 patients with spontaneous haemorrhages were studied. The time of ICP recording varied from 7.57 days (mean) in patients with ICH and 6.16 days (mean) in patients with HI respectively depending on the clinical situation. Subcortical parenchymatous haemorrhages (less than 0.5 cm in diameter) were observed in 6 patients. 2 patients suffered from meningitis but had associated rhinogenic CSF fistulas. In 16 cases without clinical signs of meningitis bacterial contamination of the catheter or the CSF was observed. Dislocation of the ventricular catheter during transport occurred in another 7 patients. In 6 cases the ventricular catheter occluded and had to be replaced. There were no statistical significant differences concerning the frequency of the different complications in both groups. From the low complication rate we conclude that ventriculostomy still is the "golden standard" of ICP recording.

Adolescent↗
PubMed1993

Early and late systemic hypotension as a frequent and fundamental source of cerebral ischemia following severe brain injury in the Traumatic Coma Data Bank.

The outcome from severe head injury (GCS < or = 8 mmHg) was prospectively studied in patients from the Traumatic Coma Data Bank. We investigated the impact on outcome of hypotension (SBP < 90 mmHg) occurring from injury through resuscitation (early hypotension; N = 717) or in the Intensive Care Unit [ICU] (late hypotension; N = 493). Early hypotension occurred in 248 patients (34.6%) and was associated with a doubling of mortality (55% vs. 27%). If shock was present on admission, the mortality was 65%. These effects were independent of age, admission GCS motor score, presence of hypoxia, or associated severe extracranial trauma, suggesting that the influence of multiple system trauma in head injured patients is primarily due to associated hypotension. Late hypotension occurred in 156 of 493 patients (32%) and was the only hypotensive episode in 117 (24%). For 117 patients whose only hypotensive episode occurred in the ICU, 66% either died or were vegetative survivors, compared to 17% of patients who never suffered an hypotensive episode. Logistic regression modelling suggested that early and late shock were the most powerful independent predictors of mortality in this group of patients. These data demonstrate that hypotension is a common and devastating secondary brain insult in severe head injury patients, occurring not only during transport and resuscitation but also "right under our noses" in the ICU. We suggest that vigorous attention to eliminate or minimize such insults has the potential of markedly improving outcome from severe head injury.

Adolescent↗
PubMed1992

Extracranial complications of severe head injury.

In order to define the role of intracranial and extracranial complications in determining outcome from severe head injury, 734 patients from the Traumatic Coma Data Bank were analyzed. Nine classes of intracranial and 13 classes of extracranial complications occurring within the first 14 days after admission were analyzed, while controlling for age, admission Glasgow Coma Scale motor score, early hypoxia or hypotension, and severe extracranial trauma. Outcome for survivors was based on the last recorded Glasgow Outcome Scale score, obtained a median of 521 days after injury. Intracranial complications did not significantly alter outcome for the study group. Of the extracranial complications, pulmonary, cardiovascular, coagulation, and electrolyte disorders occurred most frequently at 2 to 4 days. Infections developed later, peaking at 5 to 11 days. Gastrointestinal, renal, and hepatic complications followed no specific time course. Electrolyte abnormalities were the most frequent occurrence (59% of patients) but did not alter outcome. Pulmonary infections (41%), shock (29%, systemic blood pressure < or = 90 mm Hg for 30 minutes or more), coagulopathy (19%), and septicemia (10%) were significant independent predictors of an unfavorable outcome. Backward-elimination, stepwise logistic regression modeling indicated that the estimated reduction of unfavorable outcome was 2.9% for the elimination of pneumonia, 3.1% for coagulation disturbances, 1.5% for septicemia, and 9.3% for shock. These data suggest that extracranial complications are highly influential in determining the outcome from severe head injury and that significant improvements in outcome in a sizeable proportion of patients could be accomplished by improving the ability to prevent or reverse pneumonia, hypotension, coagulopathy, and sepsis.

Adolescent↗