PubMed Health⌕ Search

Biomedical subjects

A van Zundert

Publications and source records attributed to A van Zundert.

16 recordsLinked to original sources
PubMed2006

The anatomical position of three extraglottic airway devices in patients with clear airways.

We tested the hypothesis that, in patients with clear airways, the anatomical position of three single-use extraglottic airway devices is similar. The airways studied were: the laryngeal mask airway unique (LMA-U), the Softseal laryngeal mask airway (SS-LM) and the Cobra perilaryngeal airway (Cobra-PLA). Three hundred spontaneously breathing patients were randomly allocated to have their airway managed using one of these three supraglottic airway devices. A rigid endoscope was passed down the airway tube and the following anatomical assessments were made: position of the epiglottis; position of the glottis; and position of the cuff. The epiglottis was more frequently visible with the LMA-U than with the SS-LM (76 vs 57%, p = 0.006) and with the LMA-U than with the Cobra-PLA (76 vs 46%, p < 0.0001). The epiglottis was in contact with the mask aperture bars in 25% of patients, and in 34% of these, the epiglottis was seen to be herniated through the aperture bars. Herniation of the epiglottis through the mask aperture bars occurred more frequently with the Cobra-PLA than the LMA-U (8 vs 3%, p = 0.008). The vocal cords and arytenoids were more frequently visible with the LMA-U and SS-LM than with the Cobra-PLA (both p < 0.006). Herniation of the arytenoids through the mask aperture bars was more frequently seen with the Cobra-PLA than with the LMA-U (8 vs 0%, p = 0.004). The position of the cuff was optimal for the LMA-U and SS-LM in 90% and 93% of patients, respectively. The cuff was more frequently in the midline with the LMA-U than with the SS-LM (p = 0.002). We conclude that the anatomical position of the LMA-U and SS-LMA is superior to that of the Cobra-PLA in patients with clear airways. The mask aperture bars probably have no anatomical utility and predispose to herniation of the pharyngeal structures.

Adolescent↗
PubMed2006

Differences in platelet growth factor release and leucocyte kinetics during autologous platelet gel formation.

Three commercial systems for whole blood separation were compared to obtain the buffy coat composed of platelet-rich plasma (BC-PRP) and leucocytes . These samples of the buffy coat were used to make a platelet gel (PG), which was used to measure platelet growth factor (PGF) release, to perform a white blood cell (WBC) count and to measure myeloperoxidase (MPO) release from WBCs. Aliquots of whole blood obtained from ten volunteers were distributed either to a blood cell separator (The Electa Cell-Separator, E-CS) or to a tabletop centrifuge (Gravitational Platelet Sequestration System, GPS) to prepare the BC-PRP. The third system combines the BC-PRP production by E-CS with a micro porous filter (Autologous Growth Factor filter, AGF) to enrich for the BC-PRP. Autologous thrombin was used to activate the BC-PRP and to prepare the PG and subsequently to degranulate the platelet concentrate. Platelet-derived growth factor-AB and transforming growth factor-beta1 were present in high levels after thrombin activation of the E-CS or GPS prepared samples. However, the AGF prepared samples released their growth factors before thrombin activation. The WBCs were significantly increased with each of the three systems. Contrary to the AGF, no leucocyte degranulation occurred with the E-CS or GPS prepared samples, based upon the low MPO concentrations in the BC-PRP. The three types of apparatus had different harvesting capacities for collecting the enriched platelets and the release of high concentrations of PGF. When the E-CS and GPS, but not the AGF, were used, low levels of MPO were maintained in the PG, which potentially contributes to antimicrobial properties of platelet gel at the site of application.

Adult↗
PubMed2006

Platelet gel and fibrin sealant reduce allogeneic blood transfusions in total knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is often associated with a considerable amount of post-operative blood loss, necessitating the transfusion of allogeneic blood, which can add to the complications. Optimization of strategies to reduce the need for blood transfusion is desired. This study was designed to evaluate the efficacy of autologous platelet gel and fibrin sealant in unilateral TKA. METHODS: Consecutive patients were operated on and assigned to the study and control groups. Study group patients (n = 85) were operated on according to our standard TKA protocol, with the application of autologous platelet gel and fibrin sealant on the wound tissues at the end of surgery. Eighty patients were operated on according to the same protocol, but without the use of platelet gel and fibrin sealant, and served as the control group. All blood transfusions, occurrence of wound leakage, wound healing disturbances and incidences of post-operative infections were recorded. RESULTS: Patients in the treatment group had a significantly higher post-operative haemoglobin level (11.3 vs. 8.9 g/dl, respectively) and a decreased need for allogeneic blood products (0.17 vs. 0.52 units, respectively) than those in the control group (P < 0.001). The incidences of wound leakage and wound healing disturbance were significantly less (P < 0.001) in patients managed with platelet gel and fibrin sealant. Four patients in the control group, who received blood products, developed wound infection. The hospital stay was decreased by 1.4 +/- 1.5 days for patients in the treatment group (P < 0.001). CONCLUSION: Peri-operatively applied platelet gel and fibrin sealant may reduce the incidence of allogeneic blood transfusions and complications associated with TKA.

Aged↗
PubMed2006

The frozen shoulder syndrome. Description of a new technique and five case reports using the subscapular nerve block and subscapularis trigger point infiltration.

BACKGROUND AND OBJECTIVES: A frozen shoulder is considered by some authors to be a common stage of many disorders affecting the shoulder, while others regard it as an independent idiopatic condition. A consistent finding is that subscapularis muscle trigger points play a key role in the development of the frozen shoulder syndrome. Apart from the conventional treatment, a selective subscapularis fossa nerve block combined with subscapularis trigger points infiltration, may be an effective treatment in preventing chronic pain. METHODS: In this manuscript the posterior injection technique of the subscapularis fossa nerve block is described. RESULTS: Five patients with typical symptoms of frozen shoulder, who did not respond to conventional treatment, but obtained pain relief after a combination of a subscapularis nerve block with the infiltration of trigger points, are presented. CONCLUSION: The results of this block in various painful situations of the shoulder region suggest the importance of subscapularis muscle in the etiology of the frozen shoulder. Using this technique, we could demonstrate that a subscapular nerve block and subscapularis trigger points infiltration have both a diagnostic and therapeutic value for the treatment of the frozen shoulder.

Adult↗
PubMed2000

Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials.

OBJECTIVES: To obtain reliable estimates of the effects of neuraxial blockade with epidural or spinal anaesthesia on postoperative morbidity and mortality. DESIGN: Systematic review of all trials with randomisation to intraoperative neuraxial blockade or not. STUDIES: 141 trials including 9559 patients for which data were available before 1 January 1997. Trials were eligible irrespective of their primary aims, concomitant use of general anaesthesia, publication status, or language. Trials were identified by extensive search methods, and substantial amounts of data were obtained or confirmed by correspondence with trialists. MAIN OUTCOME MEASURES: All cause mortality, deep vein thrombosis, pulmonary embolism, myocardial infarction, transfusion requirements, pneumonia, other infections, respiratory depression, and renal failure. RESULTS: Overall mortality was reduced by about a third in patients allocated to neuraxial blockade (103 deaths/4871 patients versus 144/4688 patients, odds ratio=0.70, 95% confidence interval 0.54 to 0.90, P=0. 006). Neuraxial blockade reduced the odds of deep vein thrombosis by 44%, pulmonary embolism by 55%, transfusion requirements by 50%, pneumonia by 39%, and respiratory depression by 59% (all P<0.001). There were also reductions in myocardial infarction and renal failure. Although there was limited power to assess subgroup effects, the proportional reductions in mortality did not clearly differ by surgical group, type of blockade (epidural or spinal), or in those trials in which neuraxial blockade was combined with general anaesthesia compared with trials in which neuraxial blockade was used alone. CONCLUSIONS: Neuraxial blockade reduces postoperative mortality and other serious complications. The size of some of these benefits remains uncertain, and further research is required to determine whether these effects are due solely to benefits of neuraxial blockade or partly to avoidance of general anaesthesia. Nevertheless, these findings support more widespread use of neuraxial blockade.

Anesthesia, Epidural↗
PubMed2000

Diffusion of n-butyl-p-aminobenzoate (BAB), lidocaine and bupivacaine through the human dura-arachnoid mater in vitro.

INTRODUCTION: Epidural administration of a suspension of n-butyl-p-aminobenzoate (BAB) to humans resulted in a selective, ultra-long lasting sensory block without motor function impairment. The absence of motor block was attributed to 'spatial' confinement of active concentrations of dissolved BAB within the epidural space. This study was designed to investigate the diffusion of BAB through the human dura-arachnoid membrane in vitro relative to lidocaine and bupivacaine and to quantify the influence of the composition of the suspension formulation on this flux. MATERIALS AND METHODS: Human dura-arachnoid specimens were mounted between the donor and the receiver compartment of a diffusion cell. Five concentrations of BAB, lidocaine and bupivacaine in phosphate-buffered saline, pH 7.4, were added to the donor compartment and the increase of the concentration of the agent in time in the receiver compartment was measured by automated UV-spectrometry. Fluxes and permeabilities were calculated. The influence of pH, polysorbate 80 (PS 80) and polyethylene glycol 3350 (PEG 3350) on the flux of BAB in solution and in suspension formulations were analyzed. RESULTS: The flux of both lidocaine and bupivacaine at pH 4 was considerably smaller than at pH 7.4. Permeabilities decreased in the order bupivacaine>lidocaine&z.Gt;BAB and at the level T12>T1. PS 80 at concentrations exceeding 0.025 mg/ml and PEG 3350 decreased the flux of BAB from BAB-solutions. Used in the preparation of the suspension, PS 80 and PEG 3350 did significantly reduce the permeability. DISCUSSION: The results of this study are consistent with the hypothesis that the selective action of epidurally applied BAB suspension can be attributed to the spatial confinement of active BAB-concentrations within the epidural space. Additives used in the preparation of the aqueous suspension formulation may substantially influence the local pharmacokinetics and by that the pharmacodynamic effects.

Anesthetics, Local↗
PubMed1992

Blood loss and use of blood in internal mammary artery and saphenous vein bypass grafting with and without adding a single, low-dose of aprotinin (2 million units) to the pump prime.

In comparison with saphenous vein bypass grafting (SVG) without a pleurotomy, internal mammary artery (IMA) bypass surgery might enhance more blood loss by the intrathoracic wound and a wide opened pleura. Low-dose aprotinin (Trasylol) reduces blood loss and consequently, the use of homologous blood. We studied the blood loss and blood requirements peri-operatively in 70 patients, who underwent either SVG-(n = 35) or IMA-surgery (n = 35) without aprotinin and another 70 patients who underwent SVG- (n = 35) or IMA-surgery (n = 35) with a single dose of aprotinin, added to the pump prime. We also determined the hemoglobin and total protein content of the shed blood. Without aprotinin administration, the mean intra-operative and post-operative blood loss was significantly less (p < 0.01) in SVG-patients, than in IMA-patients. We observed no statistical differences in the mean blood requirements between SVG- and IMA-surgery (1.2 units and 1.6 units). The use of any homologous blood product was similarly averted in 39% of the SVG-patients, and in 48% of the IMA-patients. Treatment with aprotinin significantly lessened (p < 0.01) the mean intra-operative blood loss only in IMA-patients. Post-operative blood loss was diminished with 45% in IMA-patients and 33% in SVG-patients, being significantly less (p < 0.01) after SVG, than after IMA-surgery. Blood requirements were significantly lowered (p < 0.01): a total mean of 0.2 units in SVG- and 0.6 units in IMA-patients (NS). Any homologous blood product was prevented in 78% of the IMA-patients and in 87% of the SVG-patients (NS). The mean loss of hemoglobin and total protein per 100 ml of shed blood was similar in IMA-, and SVG-patients with or without aprotinin, although aprotinin diminished the total amounts in both groups with 50% (p < 0.01).

Adult↗
PubMedDate not supplied

New perspectives in the microscopic structure of human dura mater in the dorsolumbar region.

BACKGROUND AND OBJECTIVES: The object of this study was to describe the three-dimensional structure of the dura mater by use of scanning electron microscopy. METHODS: Microscopic dissection of the dura mater from four fresh cadavers (aged 70, 75, 76, and 80 years) 8-12 hours after death were investigated in three different planes (longitudinal, tangential, and transverse). RESULTS: The external surface of the dura mater, facing the epidural space, consisted of a network of randomly oriented fine collagen fibers. The thicker elastic fibers (2 microns in diameter) were observed on the surface of the dura. In the inner part of the dura mater, there were very fine lamellae of collagen fibers, which were bundled into thicker (4-5 microns) layers. The dura mater consisted of 78-82 layers, each layer including 8-12 very fine lamellae. CONCLUSIONS: The fibers of the dura mater do not run in a longitudinal direction and are not arranged in a parallel fashion. Cytoarchitecturally the dura mater is a laminated structure built up from well-defined layers oriented concentrically around the medulla spinalis.

Aged↗
PubMedDate not supplied

A loss-of-resistance-to-negative-pressure test for subarachnoid puncture with narrow-gauge needles.

BACKGROUND AND OBJECTIVES: Approximately 5-10% of attempted myelograms are spoiled by partial subdural injection. Similar spillage of local anesthetics may underlie the wide variability of segmental spread reported for spinal anesthesia. A technique of applied negative pressure to avoid accidental subdural injection and to facilitate subarachnoid puncture with narrow gauge needles is described. METHODS: Hydraulic circuitry was designed to measure saline flow rates through spinal needles at hub-to-tip differential pressures of 55 mm Hg and 650 mm Hg. A model of dura and arachnoid membranes was constructed to demonstrate the effects of applied negative pressure on the subdural space during the passage of Quincke-tip and pencil-point needles. Cisternal puncture in 38 dogs and thoracic or lumbar subarachnoid puncture in 680 patients were performed using applied negative pressure to the needle hub. RESULTS: A sustained vacuum of -650 mm Hg at the hub of air-filled spinal needles was transmitted beyond the tip but fell to zero at the tip as the shaft filled with saline. Flow rates through the Quincke needles, ranging from 22-gauge to 29-gauge, rose 22- to 33-fold when a vacuum of -650 mm Hg was applied at the hub. Model dura and arachnoid membranes were separated by air-filled tips at atmospheric pressure but were juxtaposed by negative pressure applied to the hub. CONCLUSIONS: Negative pressure applied to the needle hub is transmitted to the tip without decrement in air-filled needles but not in fluid-filled needles. Clinical application of this principle by exertion of strong negative pressure at the hub during needle advancement facilitates rapid identification of cerebrospinal fluid, avoids unintentional subdural injection of local anesthetics or contrast media, and increases the safety of subarachnoid punctures above the termination of the spinal cord.

Animals↗