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Biomedical subjects

P K Hol

Publications and source records attributed to P K Hol.

11 recordsLinked to original sources
PubMed2006

Agreement between PiCCO pulse-contour analysis, pulmonal artery thermodilution and transthoracic thermodilution during off-pump coronary artery by-pass surgery.

BACKGROUND: Haemodynamic instability during off-pump coronary artery bypass surgery (OPCAB) may appear rapidly, and continuous monitoring of the cardiac index (CI) during the procedure is advisable. With the PiCCO monitor, CI can be measured continuously and almost real time with pulse-contour analysis and intermittently with transthoracic thermodilution. The agreement between pulmonal artery thermodilution CI (Tpa), transthoracic thermodilution CI (Tpc) and pulse-contour CI (PCCI) during OPCAB surgery has not been evaluated sufficiently. METHODS: In 30 patients scheduled for OPCAB surgery, a pulmonary artery catheter and a PiCCO catheter were inserted. At different time points during surgery, Tpa, Tpc and PCCI were compared. Measurements were performed after induction of anesthesia (T1), after pericardiothomy (T2), after grafting on the anterior (T3), posterior (T4) and lateral (T5) walls and after chest closure (T6). The PCCI was recalibrated at time point T2-T6. RESULTS: Mean difference and the limits of agreements (percentage error) between Tpa and Tpc were: -0.14 +/- 0.60 (22.0%) l/min/m2, between Tpa and PCCI: -0.07 +/- 0.92 (33.5%) l/min/m2 and between Tpc and PCCI: 0.10 +/- 1.00 (35.5%) l/min/m2. For changes in CI from one time point to the next (DeltaCI), the limits of agreements between DeltaCI Tpa and DeltaCI Tpc were 0.04 +/- 0.90 l/min/m2, between DeltaCI Tpa and DeltaCI PCCI: -0.02 +/- 1.22 l/min/m2 and between DeltaCI Tpc and DeltaCI PCCI: -0.08 +/- 1.32 l/min/m2. CONCLUSION: In OPCAB surgery, limits of agreement comparing thermodilution methods were smaller than comparing PCCI with thermodilution. Recalibration of PCCI is therefore advisable.

Adult↗
PubMed2005

Impact of intraoperative MRI on the surgical results for high-grade gliomas.

OBJECTIVE: The impact of intraoperative MRI (iMRI) on the surgical procedure, patient outcome and median survival for a series of patients harbouring high-grade gliomas forms the basis of this study. Their outcome has been compared to a matched cohort of patients operated in a conventional manner to determine if the use of intraoperative MRI can be shown to improve the results of surgery and prognosis for this type of patient. MATERIALS AND METHODS: 32 microsurgical open craniotomies, performed in the intraoperative iMRI scanner for grade IV supratentorial gliomas, with follow-up periods of more than 2 months, were analyzed for this study. A group of 32 primary high-grade glioma patients (no recurrent tumors) were matched for age, preoperative clinical grade, gender and histology and operated during a corresponding time interval in a conventional manner acted as controls. RESULTS: All 64 patients were examined and analyzed for the occurrence of postoperative increased neurological morbidity or death. No complications directly related to the intraoperative scanning procedures were observed and no intraoperative death occurred in either group. The average operating time in the intraoperative scanner was 5.1 hours and was significantly longer than in the conventional OR (3.4 hours). The mean overall survival time for the 32 patients in the study group was 14.5 months (95 % confidence interval 12.0 - 16.6) compared to 12.1 months (95 % confidence interval 10.2 - 14.1) for the matched control group. CONCLUSION: Although iMRI is an effective way of imaging residual tumor, this study could not demonstrate an increased efficacy of surgery utilizing this technique for patients harbouring grade IV gliomas compared to more conventional methods. No statistical significance was noted between the two groups (p = 0.14). The complication rate was within the range reported for other series, in both control as well as the study group.

Adult↗
PubMed2001

[Cryoablation--a treatment option for inoperable liver tumors?].

BACKGROUND: Most patients with primary and secondary liver tumours are inoperable by conventional surgery. This has prompted the development of different techniques of local destruction of liver tumours, i.e. cryosurgical ablation radiofrequency, laser, and microwave ablation. MATERIAL AND METHODS: On the basis of relevant literature and our own experience we describe the principles of local destruction by cryoablation of colorectal metastases. RESULTS: Indications for ablation are mainly colorectal metastases and hepatocellular carcinoma. Mechanisms for tumour destruction include intra- and extracellular ice crystal formation, cellular membrane rupture, cellular dehydration and ischaemic damage. Ablation is regularly monitored by ultrasonography, which is suboptimal because of inadequate visualisation of the iceball. Long-term outcome of local destruction of liver tumours is not documented and randomized trials are not ethically acceptable. This complicates analyses of patient outcomes. INTERPRETATION: Local ablation of liver tumours is experimental therapy and should only be performed as a part of prospective trials.

Carcinoma, Hepatocellular↗
PubMed2001

Magnetic-resonance-guided percutaneous cryoablation of hepatic tumours.

OBJECTIVE: To study the feasibility of percutaneous cryoablation of hepatic tumours monitored by magnetic resonance imaging (MRI). DESIGN: Prospective study SETTING: University hospital, Norway PATIENTS: Six patients with hepatic metastases from colorectal cancer. INTERVENTIONS: Percutaneous cryoprobe positioning under general anaesthesia. Positioning and freezing monitored by near-real-time MRI using an open 0.5 Tesla MRI configuration system. MAIN OUTCOME MEASURES: Safety and feasibility of the procedure. Measurement of volumes of cryolesions. RESULTS: One patient developed a biliary leakage that had to be drained. Four patients developed pleural fluid. Two small tumours were adequately cryoablated. In the remaining 4 patients with large (>4 cm) tumours, an adequate cryolesion could not be formed. Cryolesion volumes larger than 105 cm3 were not produced even using 3-4 probes. MRI visualised the growing cryolesion well, but positioning of the cryoprobes was time-consuming. CONCLUSION: MR guided cryoablation is clinically feasible and gives good visualisation of the procedure. Patients with small tumours (<3 cm) seem to be best suited to this percutaneous approach as cryolesion volumes claimed to be adequate for tumour destruction can be produced. Measurement of tumour volume preoperatively may help to select patients who will respond.

Aged↗
PubMed2001

Graft control by transit time flow measurement and intraoperative angiography in coronary artery bypass surgery.

BACKGROUND: The aim of this study was to compare the relationship between intraoperative transit time flow measurements and angiographic findings with long-term graft patency in 72 patients who underwent coronary artery bypass surgery. METHODS: Transit time flow measurements with recording of mean flow and pulsatility indexes were performed after completion of the anastomoses. Coronary angiography was performed on-table while the patients were still in general anesthesia, and then at follow-up three months and 12 months after surgery. Based on angiography, the grafts were graded as type A (fully patent), type B (having more than 50% diameter reduction), or type O (occluded). RESULTS: Of the 67 left internal mammary artery (LIMA) grafts, 51 (76%) were type A on-table, 14 (21%) were type B, and two (3%) were type O. Of the 57 saphenous vein grafts, 49 (86%) were type A, 7 (12%) were type B, and one (2%) was type O. For both LIMA and vein grafts, there were no differences in flow (p = 0.69 and 0.47, respectively) or pulsatility index (p = 0.79 and 0.83) between type A and B. There were also no differences in flow (p = 0.37 and 0.7) or pulsatility index (p = 0.37 and 0.24) between type B on-table that either normalized or persisted occluded at the follow-up. Transit time flow measurement failed to detect an occluded LIMA graft as shown by intraoperative angiography. CONCLUSIONS: Blood flow measurements performed intraoperatively could not identify significant lesions in arterial or vein grafts, and could not predict graft patency. We have become cautious in interpreting flow measurements alone and combine blood flow recordings with intraoperative angiography in the assessment of graft quality.

Aged↗
PubMed2000

MRI-guided celiac plexus block.

Celiac plexus block is used as a palliative procedure in cases of severe upper abdominal pain caused by pancreatitis or tumors of the pancreas. It can be guided by bony landmarks, fluoroscopy, ultrasound (US), or computed tomography (CT). To avoid severe complications, methods visualizing soft tissue, like CT and magnetic resonance (MR) imaging, are preferable. We describe celiac plexus blocks carried out in an open MR scanner, offering needle guidance with an optical tracking system and near real-time image acquisition. Eight patients with severe chronic abdominal pain were included. In these, 14 celiac blocks were carried out. Good or total pain relief was achieved in 8 of the 14 blocks (57%), a moderate effect in 5 blocks (36%), and no effect in 1 block (7%). The placement of the needle was easily guided with MR in all cases. The MR technique ensures good visualization of soft tissue, direct monitoring of needle movement and avoids exposure to ionizing radiation. Celiac plexus block can safely be carried out in an open MR scanner.

Abdominal Pain↗
PubMed1997

[Cerebral CT findings in AIDS].

A cerebral CT was performed in 82 of 525 AIDS patients, with positive findings in 46 cases. These findings included cerebral atrophy in 28 cases, pathological demyelinisation in two, progressive multifocal leukoencephalopathy in one, toxoplasmosis in 11, lymphomas in seven, infarction in one and one subdural haematoma. The radiological findings are correlated to pathology and clinical symptoms. The authors point out the importance of these findings for correct interpretation of the CT scans.

AIDS Dementia Complex↗
PubMed1992

[Intraoperative ultrasonography in brain surgery].

Intraoperative ultrasound was used in 33 patients. 19 lesions were primary malignant brain tumours, including 12 gliomas, three astrocytomas and four oligodendrogliomas. There were five metastases, three meningeomas, two dysembryoplastic neuroepithelial tumours and two angiomas. One patient had an arachnoid cyst, and another an infarct. The main advantage of carrying out intraoperative ultrasound examination is that it helps to localize the tumour, particularly in small subcortical lesions where the brain surface may appear normal. Ultrasound is less useful for characterizing the tumour, although the various tumours do show some differences. As a rule, the glioblastomas are inhomogeneous and poorly marginated, while low grade gliomas are more homogeneous and well marginated. Also meningeomas and metastases tend to be homogeneous and well marginated. Periofocal oedema is hyperechogenic compared with brain tissue, with an intensity between that of normal brain tissue and tumour mass. Cyst, calcification and haemorrhage are easily demonstrated.

Adenocarcinoma↗
PubMed1990

Axial and appendicular bone mineral content determined by computed tomography. Relationship to age and body size in males.

Bone density and mass related values were determined in femoral condyles and in the second lumbar vertebra in males of middle age. A poor agreement was found between measurements in the two locations. The measurements were compared with age and body size by means of correlation analysis and multiple regression analysis. There was a significant linear relationship between lumbar measures and age (beta coefficient -0.61 and -0.75) while the relationship with age for the femoral measures was less (beta -0.36 and -0.45). For all measurements there was a poor correlation with body size (weight, length and surface area). Bone mineral content measurements in the lumbar and appendicular skeleton have different clinical implications. When selecting a method for estimating the bone mineral content careful attention must be paid to what type of information is wanted and whether the method is adequate for that particular purpose.

Aging↗
PubMedDate not supplied

Demonstration of pedal arterial arcades in occlusive arteriosclerotic disease. Conventional and digital subtraction angiography compared.

Conventional arteriography, intraarterial digital subtraction angiography (DSA), and intravenous DSA were used in the evaluation of the patency of the pedal arterial arcades in 15 patients with advanced peripheral arteriosclerotic disease. Intraarterial DSA was found to be superior to conventional arteriography. In 12 of 15 patients, excellent or good results were achieved by intraarterial DSA compared with 5 or 15 patients examined by conventional arteriography. All intravenous DSA studies performed in 6 patients were classified as poor.

Aged↗