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Biomedical subjects

M J Bucx

Publications and source records attributed to M J Bucx.

At least 19 recordsLinked to original sources
PubMed2001

Decontamination of laryngoscopes in The Netherlands.

In this study the decontamination procedures of laryngoscopes in Dutch hospitals are described, based on a structured telephone questionnaire. There were substantial differences between decontamination procedures in Dutch hospitals and the standards of the APIC (Association of Professionals in Infection Control and Epidemiology), CDC (Centers of Disease Control) and ASA (American Society of Anesthesiology) were met in full in 19.4% of the hospitals. The standards of manual decontamination, used in 78% of the 139 hospitals, were particularly disappointing; manual cleaning was considered inadequate in 22.9% of these hospitals and manual disinfection did not meet the standards of the APIC, CDC or ASA in any of these hospitals. Decontamination by instrument cleaning machines as a standard procedure was used in 30 (22%) hospitals. In three of these hospitals the blades were subsequently sterilized. We suggest adherence to the infection control guidelines of the CDC, APIC and ASA, until the safety of less conservative infection control practices are demonstrated.

Disinfection↗
PubMed1999

The effect of steam sterilisation at 134 degrees C on light intensity provided by fibrelight Macintosh laryngoscopes.

We studied the repeated effect of sterilisation on light intensity in laryngoscopes from Penlon, Riester, Heine (two different blades), Medicon and Upsher. Light intensity was measured by a light meter using two methods. Measurements were performed before the decontamination procedure was carried out and subsequently after each series of 25 procedures until a total of 200 cycles was reached. Using method 1 (and 2), the reduction in light intensity after 200 cycles was 100% (100%; no light emitted), 37% (13%), 75% (69%), 79% (60%), 37% (14%) and 63% (55%) for each blade, respectively.

Equipment Failure↗
PubMed1998

An evaluation of a modified Macintosh laryngoscope in a manikin.

PURPOSE: In this manikin study a modified Macintosh blade was prospectively compared with its original focussing on the forces exerted on the maxillary incisor teeth and intubation success. The modified blade, a standard Macintosh blade with a reduced proximal flange, was intended to reduce the forces exerted on the maxillary incisors. METHODS: A manikin equipped with two sensors, to measure forces applied to the maxillary incisors in the axial and the transverse direction, was used. Fourteen staff anaesthetists and 16 residents each performed two laryngoscopies with both blades. RESULTS: All laryngoscopies resulted in successful tracheal intubation. The maximal and mean forces exerted on the teeth in the axial direction were 12 N and 5.8 N smaller (P < 0.0005 and P < 0.0005, respectively) when the modified blade was used. CONCLUSION: The use of the modified blade resulted in a reduction of the forces on the maxillary incisors whereas the intubation success rate was the same as with the original. Studies in manikins can be useful in comparative laryngoscope testing.

Humans↗
PubMed1997

Reshaping the Macintosh blade using biomechanical modelling. A prospective comparative study in patients.

It has been demonstrated that during routine use of the Macintosh blade, great forces are exerted on the maxillary incisors. The aim of this study was, by using biomechanical modelling, to modify a standard Macintosh blade in order to reduce these forces. This resulted in a Macintosh blade with a reduced proximal flange. Five anaesthetists performed tracheal intubation in 46 patients using the modified (n = 24) or the standard blade (n = 22). The mean (SD) maximal forces exerted on the maxillary incisors were 12.7 (8.8) N in patients in the modified Macintosh group compared to 25.5 (17.8) N in the standard Macintosh group (p = 0.008). These results demonstrate that reducing the proximal step of the Macintosh laryngoscope results in a reduction of the forces exerted on the teeth and suggest that laryngoscope blades with a high proximal step might be more traumatic than blades in which the proximal step is reduced.

Adult↗
PubMed1996

Transverse forces exerted on the maxillary incisors during laryngoscopy.

PURPOSE: In this study the effect of level of experience of the intubator on the forces applied by the Macintosh laryngoscope on the maxillary incisors in both the axial and transverse direction were investigated. METHODS: Five groups of different levels of experience (15 per group), staff anaesthetists, residents, nurse anaesthetists, surgeons and students, performed one laryngoscopy and subsequent intubation on an intubation manikin equipped with sensors to measure these forces. RESULTS: Maximal transverse forces oriented toward the base of the skull (Fmtpmax) were between 0 and 10 N in 46 cases (61%), between 10 and 20 N in 21 (28%) and > or = 20 N (maximum 46.5 N) in eight cases (11%). The maximal values of the transverse forces oriented toward the intubator (Fmtnmax) were between 0 and 10 N in 69 cases (92%), between 10 and 20 N in 3 (4%) and > or = 20 N (maximum 36.4 N) in 3 (4%). Level of experience was related to Fmtpmax (Spearman: P = 0.04, r = 0.24). In addition, Fmtnmax was less in experienced intubators (anaesthetist and residents) than in inexperienced intubators (all other groups) (Student's t test: P = 0.04). CONCLUSION: In contrast to the effect on forces exerted in the axial direction, experience proved to have a beneficial effect on the forces in the transverse direction.

Humans↗
PubMed1995

Does experience influence the forces exerted on maxillary incisors during laryngoscopy? A manikin study using the Macintosh laryngoscope.

The influence of the level of experience of the laryngoscopist on the duration of laryngoscopy, the forces exerted on the tongue and on the maxillary incisors during laryngoscopy, were investigated. Five groups (anaesthetists, residents in anaesthesia, nurse anaesthetists, surgeons and medical students), each consisting of 15 individuals, participated in the study. An intubation manikin was used with a laryngoscope modified so that the forces applied during laryngoscopy could be measured. The mean duration of laryngoscopy in these groups was 23.4 sec, 17.6 sec, 27.1 sec, 26.8 sec and 42.7 sec, respectively. The maximally applied forces on the tongue were 71.7 N, 60.5 N, 65.9 N, 74.2 N and 69.7 N, respectively. The maximally applied forces on the maxillary incisors were 49.9 N, 36.3 N, 41.1 N, 58.3 N and 53.9 N, respectively. These results indicate the level of experience has a significant influence on the duration of laryngoscopy but seems to have little influence on the forces applied to the tongue and the maxillary incisors.

Anesthesiology↗
PubMed1994

Forces acting on the maxillary incisor teeth during laryngoscopy using the Macintosh laryngoscope.

We determined the forces on the maxillary incisors during routine laryngoscopy in 65 adult patients. The forces were measured by a strain gauge based sensor positioned between the handle and the blade of the laryngoscope. The mean maximal force acting on the maxillary incisors was 49 N. In patients without maxillary incisors, the force acting on the gums was significantly lower at 21 N (p < 0.001). These results suggest that, despite traditional advice to the contrary, a levering movement of the laryngoscope, using the maxillary incisors (or gums) as a fulcrum, is common practice. Biomechanical analysis revealed that, although levering is not the preferred movement, it is an efficient way of bringing the glottis into view. These results may have implications for future laryngoscope design.

Adult↗
PubMed1994

Forces applied during laryngoscopy in children. Are volatile anaesthetics essential for suxamethonium induced muscle rigidity?

Increased masticatory muscle tone after administration of suxamethonium has been demonstrated in children when combined with volatile anaesthetics. Whether volatiles are a prerequisite for this phenomenon is not known. In this study upper airway muscle tone, including the tone of the masticatory muscles, was determined in 54 children (age range 2-15 years), anaesthetized with propofol, fentanyl and nitrous oxide and avoiding any use of volatiles. The children were either relaxed with suxamethonium (n = 26) or vecuronium (n = 28). The forces applied during laryngoscopy were used to quantify upper airway muscle tone and were significantly greater in the suxamethonium group than in the vecuronium group: maximally applied force was 25 N versus 21 N (P = 0.008), and mean applied force was 16 N versus 13 N (P = 0.006), respectively. The results of this study indicate that upper airway muscle tone increases after administration of suxamethonium in children independent of the presence of volatile anaesthetics. Moreover, increased muscle tone had no effect on the difficulty of laryngoscopy or the intubation conditions. Increased masseter muscle rigidity after suxamethonium could be due to the very unique characteristics of this muscle.

Adolescent↗
PubMed1992

Measurement of forces during laryngoscopy.

The forces transmitted by the laryngoscope blade onto the base of the tongue are assumed to be a major cardiovascular stimulus. This study investigates the various forces applied onto a Macintosh laryngoscope during laryngoscopy. The forces acting along the axis of the handle are described, as well as the forces exerted by the anaesthetist to prevent the laryngoscope from turning. Based on a relatively simple technique, a modified laryngoscope has been designed to measure these forces. Four different laryngoscopic parameters are determined: (1) the duration of laryngoscopy, (2) the maximally applied force, (3) the mean force and (4) the integral of the force over the time (area under the curve). The force measurements of 49 anatomically normal patients undergoing uncomplicated intubation are included in the study. The duration of laryngoscopy was 16.3s (SD 11.8), the applied peak force was 35N (SD 12) and mean force necessary was 20N (SD 6) while the force-time integral was 324N (SD 194).

Adult↗
PubMed1992

Forces applied during laryngoscopy and their relationship with patient characteristics. Influence of height, weight, age, sex and presence of maxillary incisors.

The relationships between patients' height, weight, age, body mass index, gender and presence of maxillary incisors and a series of laryngoscopic factors have been studied. These included the duration of laryngoscopy, maximally applied force, mean applied force and the integral of force over time. There was a positive correlation between height and weight and laryngoscopic factors. Sex and age also showed a positive correlation but these could be explained by differences in height, weight and the presence of maxillary incisors. This latter factor was the dominant patient characteristic influencing the measured laryngoscopic factors. Use of these laryngoscopic factors as a measure of difficulty of laryngoscopy is discussed.

Adolescent↗
PubMed1992

Cardiovascular effects of forces applied during laryngoscopy. The importance of tracheal intubation.

The relationship between the forces applied during laryngoscopy and cardiovascular changes were studied in patients undergoing laryngoscopy with or without intubation. This enabled us to differentiate between the cardiovascular effects of laryngoscopy and the effects of tracheal intubation. The forces applied during laryngoscopy were only weakly related to the cardiovascular changes, whereas tracheal intubation had a major influence. The many difficulties encountered in interpreting results from these studies are discussed. It is concluded that tracheal intubation causes more cardiovascular changes than laryngoscopy in routine uncomplicated procedures.

Adolescent↗
PubMed1988

Comparison of acidified glycerol lysis test, Pink test and osmotic fragility test in hereditary spherocytosis: effect of incubation.

In this study we compared the results of the acidified glycerol lysis test, the Pink test and the osmotic fragility test in 38 patients with hereditary spherocytosis and in healthy controls. The sensitivity of the acidified glycerol lysis test was 81.6% when performed within 3 h after blood collection. After incubating for 24 h, the sensitivity increased to 100% whereas the specificity remained maximal. Similar incubation did not improve the diagnostic utility of the Pink test. All patients, but none of the controls, showed a positive osmotic fragility test. It is concluded, because of sensitivity and specificity in this study, that the acidified glycerol lysis test after incubation and the osmotic fragility test are superior to the Pink test in detecting spherocytosis.

Adolescent↗