Brands Of Tubes Research Articles

Comparison of Various Blood Vacuum Tubes Brand for Clinical Chemistry, Hormonal, Hematology, and Hemostasis Parameters

Link of Video Abstract: https://youtu.be/O7-fCHyvGo4 Background: Laboratory tests are integral to the medical decision-making process. Blood vacuum tubes need to be validated to increase the analytics quality. This study aimed to compare various vacuum tube brands that use serum clot activator and serum separator tube (SST) for clinical chemistry and hormonal parameters, K3EDTA anticoagulant for hematological parameters, and citrate for hemostasis parameters. Methods: The comparative study was carried out cross-sectional in the Department of Clinical Pathology, Dr. Cipto Mangunkusumo National Public Hospital, on June 20, 2020. There were 20 subjects for each type of tube. The control tube was BD Vacutainer®, and the test tubes were Samplix®, VACUETTE®, Vacusera®, and YCHD. Results: Underfilling was the most common problem in preanalytical observation. This problem for citrate tubes was most frequently found in Vacusera® tubes. The possible cause of underfilling is the expiration date, which was close to the date of the experiment. There was a significant difference in PT results (p <0.0001) in the Vacusera® citrate tube. All tube brands had no significant differences in all clinical chemistry, hormonal, and hematological parameters (P>0.05). After 24 hours at room temperature, the results of hematological parameters showed statistically significant differences in MCV and hematocrit parameters, while other parameters were still within the CV limit of the instrument. Conclusion: There were no significant differences in the results of clinical chemistry, hormonal, and hematological parameters for all tube brands. A hematology parameters test should be done immediately as the delay may affect the MCV and hematocrit parameters.

Multicentre verification of haematology laboratory blood collection tubes during a global blood collection tube shortage.

Verification of blood collection tubes is essential for clinical laboratories. The aim of this study was to assess performance of candidate tubes from four alternative suppliers for routine diagnostic haematology testing during an impending global shortage of blood collection tubes. A multicentre verification study was performed in Cape Town, South Africa. Blood from 300 healthy volunteers was collected into K2 EDTA and sodium citrate tubes of BD Vacutainer® comparator tubes and one of four candidate tubes (Vacucare, Vacuette®, V-TUBE™ and Vacutest®). A technical verification was performed, which included tube physical properties and safety. Routine haematology testing was performed for clinical verification. Vacucare tubes did not have a fill-line indicator, Vacuette® tubes had external blood contamination on the caps post-venesection and Vacutest® tubes had hard rubber stoppers. K2 EDTA tubes of Vacuette®, Vacucare and Vacutest® performed similarly to the comparator. Unacceptable constant bias was seen for PT in Vacucare (95% CI -2.38 to -0.10), Vacutest® (95% CI -1.91 to -0.49) and Vacuette® (95% CI 0.10-1.84) tubes and for aPTT in Vacuette® (95% CI 0.22-2.00) and V-TUBE™ (95% CI -2.88 to -0.44). Unacceptable %bias was seen for aPTT in Vacucare (95% CI 2.78-4.59) and Vacutest® tubes (95% CI 2.53-3.82; desirable ±2.30), and in V-TUBE™ for mean cell volume (95% CI 1.15-1.47, desirable ±0.95%) and mean cell haemoglobin concentration (95% CI -1.65 to -0.93, desirable ±0.43%). Blood collection tubes introduce variability to routine haematology results. We recommend that laboratories use one brand of tube. Verification of new candidate tubes should be performed to ensure consistency and reliable reporting of results.

Evidence for Contamination of Silica Microparticles in Advanced Platelet-Rich Fibrin Matrices Prepared Using Silica-Coated Plastic Tubes.

Platelet-rich fibrin (PRF) therapy has been widely applied in regenerative dentistry, and PRF preparation has been optimized to efficiently form fibrin clots using plain glass tubes. Currently, a shortage of commercially available glass tubes has forced PRF users to utilize silica-coated plastic tubes. However, most plastic tubes are approved by regulatory authorities only for diagnostic use and remain to be approved for PRF therapy. To clarify this issue, we quantified silica microparticles incorporated into the PRF matrix. Blood samples were collected into three different brands of silica-containing plastic tubes and were immediately centrifuged following the protocol for advanced-PRF (A-PRF). Advanced-PRF-like matrices were examined using a scanning electron microscope (SEM), and silica microparticles were quantified using a spectrophotometer. Each brand used silica microparticles of specific size and appearance. Regardless of tube brands and individual donors, significant, but not accidental, levels of silica microparticles were found to be incorporated into the A-PRF-like matrix, which will be consequently incorporated into the implantation sites. Presently, from the increasing data for cytotoxicity of amorphous silica, we cannot exclude the possibility that such A-PRF-like matrices negatively influence tissue regeneration through induction of inflammation. Further investigation should be performed to clarify such potential risks.

Double-lumen tracheal tubes and bougies: a bench study to investigate factors that influence the risk of shearing.

Tracheal intubation with a double-lumen tube can be more challenging than with a single-lumen tube. A bougie can be used to facilitate intubation. Case reports have described fragment shearing from bougies when they are removed from the tube after intubation. These fragments have the potential to cause harm. It has even been suggested that bougies and double-lumen tubes should not be used together. We conducted a benchtop trial to investigate factors that influence the risk of shearing. We investigated three brands of double-lumen tube (each in three sizes and both lateralities) and four brands of bougie. We simulated one intubation and 29 further insertions/removals of bougie with every bougie-double-lumen tube combination. We inspected the inside of the tube for evidence of shearing after first, tenth and thirtieth removals. We found that brand of bougie, brand of double-lumen tube and size of double-lumen tube (but not its laterality) all influenced the degree of shearing. Certain bougie-double-lumen tube combinations produced a particularly high degree of shearing, so these should be avoided.

Tube tip and cuff position using different strategies for placement of currently available paediatric tracheal tubes

BackgroundTracheal tube tip and cuff positions of different cuffed paediatric tracheal tube brands in the trachea can vary with design. MethodsData from three clinical studies with measured tracheal lengths were pooled in a database including 422 children aged from birth to 16 yr. Dimensional data of seven cuffed paediatric tracheal tube brands (ID 3.0–7.0 mm) were recorded. Positions of tracheal tube tip and upper cuff border were calculated for each of the 422 tracheas using depth mark based tracheal tube placement, placement of the tracheal tube tip at a calculated safety distance above the carina, and mid-tracheal tube placement. Percentage of accidental bronchial intubations and tracheal tube cuff positions in the subglottic or supraglottic region were calculated. ResultsDepth mark based tracheal tube placement resulted in accidental bronchial intubation of up to 18% of cases and tracheal tube cuffs being placed in the subglottic region in up to 91%. Tracheal tube tip placement at a calculated safety distance resulted in up to 54% of tube cuffs placed too high. Mid-tracheal tube placement led to 100% subglottic or supraglottic tracheal tube cuff positions. ConclusionsAll studied cuffed paediatric tracheal tubes have major design flaws potentially leading to airway complications. Tracheal tube manufacturers are urgently asked to improve the design of cuffed paediatric tracheal tubes. Alternative strategies for tracheal tube placement can allow safe tracheal tube placement of uncuffed but not of cuffed tracheal tubes.

Differences in nicotine dependence, smoke exposure and consumer characteristics between smokers of machine-injected roll-your-own cigarettes and factory-made cigarettes

BackgroundConsumption of machine-injected roll-your-own (RYO) filtered cigarettes made from pipe tobacco increased almost 7-fold from 2008 to 2011 in the United States. MethodsWe used data from the Pennsylvania Adult Smoking Study to compare the differences in sociodemographic, smoking topography, nicotine dependence, and cotinine levels between 280 smokers using factory made (FM) cigarettes and 68 smokers using RYO cigarettes. ResultsRYO smokers were older (41 vs. 37, P = 0.053), had significantly lower levels of income (P < 0.001) and education (P = 0.007), and were less likely to be fully employed (P = 0.009). RYO smokers consumed more cigarettes per day [CPD] (21 vs. 15, P < 0.001), and had a higher mean score on the Fagerström Test for Cigarette/Nicotine Dependence (5.2 vs. 4.1, P < 0.001). The main reasons for choosing RYO cigarettes were the lower cost (68%) and believed they are less harmful (12%). The average cost per pack of FM cigarettes was $5.74 vs. $1.13 for RYO. In multiple regression analyses, RYO smokers had significantly lower cotinine levels across all levels of CPD. Among smokers of king-size cigarettes, mean interpuff interval (P < 0.05) and total smoke duration (P < 0.01) per cigarette was significantly greater in RYO smokers. In laboratory measurements, RYO cigarettes contained more tobacco by weight than FM cigarettes, but weight varied by both tobacco and cigarette tube brands. ConclusionsMachine-injected RYO cigarettes made from pipe tobacco are cheaper than FM cigarettes but may have higher abuse liability. Smokers who might otherwise reduce their cigarette consumption or quit altogether may continue to smoke RYO cigarettes due to their affordability.

Cuffed versus uncuffed endotracheal tubes for general anaesthesia in children aged eight years and under.

Since the introduction of endotracheal intubation in paediatrics, uncuffed endotracheal tubes (ETTs) have been the standard of care for children under eight years old, based on the presumption that complications, particularly postoperative stridor, are higher with cuffed ETTs. The major disadvantages of uncuffed ETTs cited for this shift in procedure include the difficulty in achieving tidal volumes due to leakage around an uncuffed ETT. To seal the airway adequately, uncuffed tubes may need to be exchanged for another tube with a larger diameter, which sometimes requires several attempts before the appropriate size is found. Uncuffed tubes also allow waste anaesthetic gases to escape, contributing significantly to operating room contamination and rendering the anaesthetic procedure more expensive. Our review summarizes the available data, to provide a current perspective on the use of cuffed versus uncuffed endotracheal tubes in children of eight years old or less. To assess the risks and benefits of cuffed versus uncuffed endotracheal tubes during general anaesthesia in children up to eight years old. We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS and Google Scholar databases from their inception until March 2017. We also searched databases of ongoing trials, and checked references and citations. We imposed no restriction by language. We included randomized and quasi-randomized controlled trials in which the effects of using cuffed and uncuffed tubes were investigated in children up to eight years old undergoing general anaesthesia. We excluded studies conducted solely in newborn babies. We applied standard methodological procedures, as defined in the Methodological Expectations of Cochrane Intervention Reviews (MECIR). We included three trials (2804 children), comparing cuffed with uncuffed ETTs. We rated the risks of bias in all three trials as high. Outcome data were limited. The largest trial was supported by Microcuff GmbH, who provided the cuffed tubes used. The other two trials were small, and should be interpreted with caution. Based on the GRADE approach, we rated the quality of evidence as low to very low.Two trials comparing cuffed versus uncuffed ETTs found no difference between the groups for postextubation stridor (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.65 to 1.33; 2734 children; quality of evidence very low). However, those two trials demonstrated a statistically significantly lower rate of endotracheal tube exchange in the cuffed ETT group (RR 0.07, 95% CI 0.05 to 0.10; 2734 children; quality of evidence very low).One trial with 70 participants found that costs per case were lower in the cuffed ETT group (mean difference (MD) EUR 19.0 lower; 95% CI 24.23 to 13.77 lower; quality of evidence low), since the higher cost of the cuffed tubes may be offset by the savings made with anaesthetic gases.No clear evidence emerged to suggest any difference between cuffed and uncuffed tubes for outcomes such as the need to treat postextubation stridor with tracheal re-intubation (RR 1.85, 95% CI 0.17 to 19.76; 115 children; 2 trials; quality of evidence very low), epinephrine (RR 0.70, 95% CI 0.38 to 1.28; 115 children; 2 trials; quality of evidence very low) or corticosteroid (RR 0.87, 95% CI 0.51 to 1.49; 102 children; 1 trial; quality of evidence very low), or need for intensive care unit (ICU) admission to treat postextubation stridor (RR 2.77, 95% CI 0.30 to 25.78; 102 children; 1 trial; quality of evidence very low).None of the trials included in this review evaluated the ability to deliver appropriate tidal volume. Implications for practiceWe are unable to draw definitive conclusions about the comparative effects of cuffed or non-cuffed endotracheal tubes in children undergoing general anaesthesia. Our confidence is limited by risks of bias, imprecision and indirectness. The lower requirement for exchange of tubes with cuffed ETTs was very low-quality evidence, and the requirement for less medical gas used and consequent lower cost was low-quality evidence. In some cases, tracheal re-intubation is required to guarantee an open airway when adequate oxygenation is difficult after removal of the tube, for a variety of reasons including stridor, muscle weakness or obstruction. No data were available to permit evaluation of whether appropriate tidal volumes were delivered. Implications for researchLarge randomized controlled trials of high methodological quality should be conducted to help clarify the risks and benefits of cuffed ETTs for children. Such trials should investigate the capacity to deliver appropriate tidal volume. Future trials should also address cost effectiveness and respiratory complications. Such studies should correlate the age of the child with the duration of intubation, and with possible complications. Studies should also be conducted in newborn babies. Future research should be conducted to compare the effects of the different types or brands of cuffed tubes used worldwide. Finally, trials should be designed to perform more accurate assessments and to diagnose the complications encountered with cuffed compared to uncuffed ETTs.

Orotracheal intubation in infants performed with a stylet versus without a stylet.

Neonatal endotracheal intubation is a common and potentially life-saving intervention. It is a mandatory skill for neonatal trainees, but one that is difficult to master and maintain. Intubation opportunities for trainees are decreasing and success rates are subsequently falling. Use of a stylet may aid intubation and improve success. However, the potential for associated harm must be considered. To compare the benefits and harms of neonatal orotracheal intubation with a stylet versus neonatal orotracheal intubation without a stylet. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and previous reviews. We also searched cross-references, contacted expert informants, handsearched journals, and looked at conference proceedings. We searched clinical trials registries for current and recently completed trials. We conducted our most recent search in April 2017. All randomised, quasi-randomised, and cluster-randomised controlled trials comparing use versus non-use of a stylet in neonatal orotracheal intubation. Two review authors independently assessed results of searches against predetermined criteria for inclusion, assessed risk of bias, and extracted data. We used the standard methods of the Cochrane Collaboration, as documented in the Cochrane Handbook for Systemic Reviews of Interventions, and of the Cochrane Neonatal Review Group. We included a single-centre non-blinded randomised controlled trial that reported a total of 302 intubation attempts in 232 infants. The median gestational age of enrolled infants was 29 weeks. Paediatric residents and fellows performed the intubations. We judged the study to be at low risk of bias overall. Investigators compared success rates of first-attempt intubation with and without use of a stylet and reported success rates as similar between stylet and no-stylet groups (57% and 53%) (P = 0.47). Success rates did not differ between groups in subgroup analyses by provider level of training and infant weight. Results showed no differences in secondary review outcomes, including duration of intubation, number of attempts, participant instability during the procedure, and local airway trauma. Only 25% of all intubations took less than 30 seconds to perform. Study authors did not report neonatal morbidity nor mortality. We considered the quality of evidence as low on GRADE analysis, given that we identified only one unblinded study. Current available evidence suggests that use of a stylet during neonatal orotracheal intubation does not significantly improve the success rate among paediatric trainees. However, only one brand of stylet and one brand of endotracheal tube have been tested, and researchers performed all intubations on infants in a hospital setting. Therefore, our results cannot be generalised beyond these limitations.

How to handle adsorption of cerebrospinal fluid amyloid β (1–42) in laboratory practice? Identifying problematic handlings and resolving the issue by use of the Aβ42/Aβ40 ratio

IntroductionWe aimed to investigate factors defining amyloid β (1–42) (Aβ1–42) adsorption during preanalytical workup of cerebrospinal fluid (CSF). MethodsCSF was transferred to new tubes ≤4 times. Variables tested were different polypropylene tube brands, volumes, CSF Aβ1–42 concentrations, incubation times, pipettes, vortex intensities, and other CSF proteins, including hyperphosphorylated tau and Interleukin 1 Receptor Accessory Protein (IL-1RAcP). An enquiry assessed the number of transfers in current practice. ResultsIn diagnostic practice, the number of transfers varied between 1 and 3. Every tube transfer resulted in 5% loss of Aβ1–42 concentration, even 10% in small volumes. Adsorption was observed after 30 seconds and after contact with the pipette tip. Tube brand, vortexing, or continuous tube movement did not influence adsorption. Adsorption for Aβ1–40 was similar, resulting in stable Aβ1–42/Aβ1–40 ratios over multiple tube transfers. DiscussionWe confirmed that adsorption of CSF Aβ1–42 during preanalytical processing is an important confounder. However, use of the Aβ1–42/Aβ1–40 ratio overcomes this effect and can therefore contribute to increased diagnostic accuracy.

Observed high incidence of buried bumper syndrome associated with Freka PEG tubes

BackgroundBuried bumper syndrome (BBS) is an uncommon but significant complication of percutaneous endoscopic gastrostomy (PEG), which occurs due to overgrowth of gastric mucosa over the inner bumper of the gastrostomy...

Intubation with a tube exchanger on an intubation trainer. Influence of tube tip position on successful intubation

Securing the airway using a tube exchanger catheter is an important and useful technique in anesthesia. Its success is mainly hampered by tube tip impingement of laryngeal structures. Advancing the tracheal tube along its normal curvature via a tube exchanger catheter has a high risk of tube tip impingement mainly of right laryngeal structures. The authors achieved successful clinical experience by rotating the tracheal tube 90° anticlockwise (ventral tube tip position) before railroading the tube via a tube exchanger catheter or a fiber optic bronchoscope through the larynx. The aim of the study was to investigate the influence of the tracheal tube tip position while intubating an airway trainer over a tube exchange catheter. Volunteer anesthetists with varying years of professional experience were asked to intubate an intubation mannequin (Laerdal Airway Management Trainer) using the orotracheal route with an established tube exchange catheter (Cook Airway Exchange Catheter, 11F). Two different brands of tracheal tubes (Rüsch and Covidien, ID 7.0mm) were used in a randomized order, each with the tracheal tube tip at first positioned right (90°), then ventrally (0°), left (270°) and finally dorsally (180°), resulting in eight intubation attempts for each participant. To ensure the correct tube tip position the tube was withdrawn before every intubation attempt until the tube tip position was visualized. The oropharnyx, larynx, trachea and tube were sufficiently lubricated with silicon spray (Rüsch Silikospray). The tube and airway exchange catheter size selection were made according to the clinical trial of Loudermilk et al. Successful endotracheal intubation without resistance was recorded for each tube tip position and tracheal tube brand. In total 20 anesthetists (13 consultants and 7 residents) with a median of 9.5 years (range 3-37 years) of professional experience participated in the study. Overall 160 intubation attempts were performed, 2 participants showed no successful intubation attempts at all and 38 out of 160 intubation attempts (23.8 %) were successful. Intubation success with the tracheal tube tip placed ventrally (0°) was 60 % followed by the left (270°) and right (90°) tracheal tube tip positions with 27.5% and 7.5 % intubation success, respectively. With the tube tip placed dorsally (180°) none of the 40 intubation attempts were successful. Intubation attempts with the Rüsch tube were more successful (28.8 %) than those with the Covidien tube (18.8 %). Placing the tracheal tube tip ventrally, the Rüsch tube was twice as successful as the Covidien tube with 16 (80 %) versus 8 attempts (40 %, p = 0.011). There was no correlation between professional experience and intubation success (p = 0.362). Tube insertion via an airway exchange catheter or a fiberoptic bronchoscope is a basic technique in anesthesia. Knowledge about the difficulties and their prevention are essential for every anesthetist. The gap between the airway exchange catheter, the fiber bronchoscope and the tube diameters is one of the major reasons for tube tip impingement. This investigation showed that intubation success via a tube exchange catheter, as investigated in an intubation mannequin, is considerably influenced by the tracheal tube tip position. A 90° anticlockwise rotation, placing the tracheal tube tip ventrally, considerably increased intubation success. This is of particular importance if an anesthesia department has no appropriately sized tube exchange catheters or fiber bronchoscope for every age group of patients.

Pre-analytical issues in the measurement of circulating microparticles: current recommendations and pending questions

Pre-analytical issues in the measurement of circulating microparticles: current recommendations and pending questions

Sodium citrate vacuum tubes validation

Sometimes in-vitro diagnostic devices (e.g. blood collection tubes) are not validated before use or when the producer's brand is changed. The aim of this study was to validate five brands of sodium citrate vacuum tubes. Blood specimens from 50 volunteers were collected in five different tube brands (I: Venosafe, II: VACUETTE, III: BD Vacutainer, IV: LABOR IMPORT and V: S-Monovette). Routine coagulation tests [activated partial thromboplastin time (aPTT), prothrombin time (PT), and fibrinogen (FIB)] were performed on ACL TOP instrument using HemosIL reagents. The significance of the differences between samples was assessed by paired Student's t-test, set at P < 0.005. Significant differences were observed for: PT when comparing I vs. II, I vs. III, I vs. V, II vs. III, II vs. IV, II vs. V, III vs. IV, III vs. V and IV vs. V; aPTT when comparing I vs. II, I vs. III, I vs. IV, II vs. IV, III vs. IV and IV vs. V. No differences were observed among brands for FIB determination. We suggest that every laboratory management should both standardize the procedures and frequently evaluate the quality of in-vitro diagnostic devices.

Evaluation of tracheal cuff pressure variation in spontaneously breathing patients

Background:Most of the studies referring cuff tubes’ issues were conducted on intubated patients. Not much is known about the cuff pressure performance in chronically tracheostomized patients disconnected from mechanical ventilation.Objective:To evaluate cuff pressure (CP) variation in tracheostomized, spontaneously breathing patients in a weaning rehabilitation center.Materials and Methods:Experimental setup to test instruments in vitro, in which the gauge (TRACOE) performance at different pressure levels was evaluated in six tracheostomy tubes, and a clinical setupin which CP variation over 24 h, every 4 h, and for 6 days was measured in 35 chronically tracheostomized clinically stable, patients who had been disconnected from mechanical ventilation for at least 72 h. The following data were recorded: Tube brand, type, and size; date of the tube placed; the patient's body position; the position of the head; axillary temperature; pulse and respiration rates; blood pressure; and pulse oximetry.Results:In vitro difference between the initial pressure (IP) and measured pressure (MP) was statistically significant (P < 0.05). The difference between the IP and MP was significant when selecting for various tube brands (P < 0.05). In the clinical set-up, 207 measurements were performed and the CP was >30 cm H2O in 6.28% of the recordings, 20-30 cm H2O in 42.0% of the recordings, and <20 cm H2O in 51.69% of the recordings.Conclusion:The systematic CP measurement in chronically tracheostomized, spontaneously breathing patients showed high variability, which was independent of tube brand, size, type, or time of placement. Consequently, measurements should be made more frequently.

Brand of dipotassium EDTA vacuum tube as a new source of pre-analytical variability in routine haematology testing

This study assesses the use of different dry K2 (dipotassium) EDTA vacuum tubes and whether or not they might represent a bias in haematological testing. Blood was collected in three dipotassium EDTA vacuum tubes from different manufacturers: Venosafe, Vacuette and Vacutainer. Samples were analysed on an Advia 2120i analyser. Significant differences among results and biases were compared with current quality specifications. Significant differences were found for haematocrit (HCT), mean corpuscular volume (MCV), white blood cell count (WBC) and platelet distribution width (PDW) when comparing Venosafe vs. Vacuette; for MCV, WBC and PDW when comparing Venosafe vs. Vacutainer; and for HCT and MCV when comparing Vacuette vs. Vacutainer. Clinically significant variations were observed for HCT and PDW in Venosafe vs. Vacuette; PDW in Venosafe vs. Vacutainer; and HCT and MCV in Vacuette vs. Vacutainer. The use of dipotassium EDTA vacuum tubes from different manufacturers represent a clinically relevant source of variation for HCT, MCV and PDW.

Effects of vigorous mixing of blood vacuum tubes on laboratory test results

ObjectiveTo evaluate the effect of tubes mixing (gentle vs. vigorous) on diagnostic blood specimens collected in vacuum tube systems by venipuncture. Design and methodsBlood was collected for routine coagulation, immunochemistry and hematological testing from one hundred volunteers into six vacuum tubes: two 3.6mL vacuum tubes containing 0.4mL of buffered sodium citrate (9NC) 0.109mol/L: 3.2W/V%; two 3.5mL vacuum tubes with clot activator and gel separator; and two 3.0mL vacuum tubes containing 5.9mg K2EDTA (Terumo Europe, Belgium). Immediately after the venipuncture all vacuum tubes (each of one additive type) were processed through two different procedures: i) Standard: blood specimens in K2EDTA- or sodium citrate-vacuum tubes were gently inverted five times whereas the specimens in tubes with clot activator and gel separator were gently inverted ten times, as recommended by the manufacturer; ii) Vigorous mix: all blood specimens were shaken up vigorously during 3–5s independently of the additive type inside the tubes. The significance of the differences between samples was assessed by Student's t-test or Wilcoxon ranked-pairs test after checking for normality. The level of statistical significance was set at P<0.05. ResultsNo significant difference (P<0.05) was detected between the procedures for all tested parameters. Surprisingly only a visual alteration (presence of foam on the top) was shown by all the tubes mixed vigorously before centrifugation (Fig. 1 A, B and C). Moreover the serum tubes from vigorous mixing procedure shows a “blood ring” on the tube top after stopper removal (Fig. 1 D). ConclusionOur results drop out a paradigm suggesting that the incorrect primary blood tubes mixing promotes laboratory variability. We suggest that similar evaluation should be done using other brands of vacuum tubes by each laboratory manager.

Rapid pressure compensation by automated cuff pressure controllers worsens sealing in tracheal tubes

Cyclic redistribution of air within the cuff during respiratory pressure changes creates a self-sealing mechanism which allows tracheal sealing, despite tracheal airway pressure being above baseline cuff inflation pressure. The aim of the present study was to investigate the effect of continuous automated cuff pressure regulation on tracheal sealing during cyclic respiratory pressure changes. In vitro tracheal sealing was studied in four different high volume-low pressure (HVLP) tracheal tube cuffs size internal diameter 8.0 and 5.0 mm in combination with a conventional pressure manometer and two different automated pressure controllers (VBM Cuff Controller; Cuff Pressure Control Tracoe). Experiments were performed at 10, 15, 20, and 25 cm H(2)O cuff pressure during intermittent positive pressure ventilation with peak inspiratory pressures of 20 and 25 cm H(2)O. Air leakage was assessed spirometrically. Experiments were performed four times with each tube brand and size with two exemplars of each of the three cuff pressure controllers. Owing to immediate cuff pressure correction, tracheal sealing at cuff pressure below inspiratory pressure was reduced in most of the tracheal tube cuffs, except in those with reduced sealing characteristics when using the Pressure Control Tracoe compared with the conventional pressure manometer and the VBM Cuff Controller. Tracheal sealing with the Pressure Control Tracoe comparable with the other two devices was only achieved at cuff pressures of 20 and 25 cm H(2)O. Automated cuff pressure controllers with rapid pressure correction interfere with the self-sealing mechanism of high sealing HVLP tube cuffs and reduce their improved sealing characteristics.

Scanning electron‐microscopic evaluation of cuff shoulders in pediatric tracheal tubes

Technical and conceptual shortcomings of cuffed pediatric tracheal tubes have been pointed out in the past, all representing a potential risk for mucosal damage of the pediatric airway. In this study, cuffed pediatric tracheal tubes from different manufacturers were investigated with regard to the cuff shoulder design using scanning electron microscopy (SEM). Cuffed pediatric tracheal tubes with the smallest internal diameter available were ordered from five manufacturers. SEM scans were performed from the tube shaft - cuff shoulder - tube cuff assembly and from the cuff shoulder alone. Each investigation was repeated in four samples of each tube brand. In addition, thickness of cuff membrane was measured. Major differences were found among the cuff shoulders investigated ranging from smooth transitions, softened borders to very sharp steps. There was also considerable difference in the thickness among the cuff membranes between the different tube brands ranging from 18 microm in polyurethane cuffs up to 90 microm in polyvinylchloride cuffs. Because the gap between the outer tracheal tube and the internal mucosal layer of the pediatric airway is often very narrow, some of the observed irregularities have the potential to injure the airway mucosa in pediatric patients, particularly during long-term use and firm fit of the tracheal tube in the airway. As cuffed tubes are increasingly used in small children, the observed irregularities in some tracheal tube brands may need to be improved and their safety should be proved by the manufacturers.

Development of a Personal Sampler for Collecting Fungal Spores

Exposure to fungal aerosols is of concern in indoor environments. However, sampling limitations have previously made it difficult to assess exposures accurately, especially long-term exposures. A prototype personal aerosol sampler, based on cyclone principles and using a 1.5 ml microcentrifuge tube as a particle collection receptacle has been designed and fabricated. Collection efficiency for aerosol particles in the size range of fungal spores has been evaluated for different types of microcentrifuge tubes, together with the effect of a polyethylene glycol coating on the inside of the tube and the effect of adding water to the tube. Monodisperse, fluorescently tagged polymer microspheres with median diameters of 0.5, 1, 2, 3, 6, 11, and 16 μm were used to evaluate sampler performance with particle diameter. The microcentrifuge-tube sampler was tested at flow rates of 2 and 4 liters per minute (l/min). Experimental results indicate that the microcentrifuge-tube sampler has an aspiration efficiency of 100% in calm air for particles up to 16 μm. At 4 l/min, the microcentrifuge-tube sampler is able to collect nearly 100% of particles greater than 3 μm and > 90% of particles between 2.5 and 3 μm. The 50% cutoff size is 1.5 μm. The performance of the sampler did not vary with the different brands of tubes tested or with the presence or absence of a coating on the tube surface. Furthermore, the addition of water to the tube resulted in a slight increase in collection efficiency. A sampling time of 5 h was feasible at 45–50% relative humidity before evaporation led to significant water loss. The cutoff size of 1.5 μm is comparable to many commercially available bioaerosol samplers. Besides being easy to use, simple to fabricate, and inexpensive, this novel sampler has several advantages over conventional samplers: long-term samples are possible (the limitation of impaction methods); there is no sample transfer loss since the transfer step has been eliminated (the limitation of filter cassettes); laboratory analyses are not dependent solely upon a single analysis method (the limitation of impaction methods), and there is no sampler adherence loss (the limitation of trying to wash microorganisms from filters). In addition, use of the sampler would be applicable in a variety of occupational settings from low bioaerosol concentrations (i.e., indoor environments) to high bioaerosol concentrations (i.e., agricultural setting) by varying sampling time periods and using sensitive analytical methods.

Estimates of bacterial production using the leucine incorporation method are influenced by differences in protein retention of microcentrifuge tubes

The most widely used methods to determine bacterial production involve measuring the incorporation of radioactive precursors, such as leucine, into macromolecular pools. The leucine method that involves incubation and extraction within a single microcentrifuge tube has become a widely used technique because of its relative convenience, precision, and low cost. We observed a discrepancy in parallel determinations of leucine incorporation for the same water samples that lead us to explore aspects of the method including tube‐washing methods, operator differences, and differences among tube brands. Operators and washing methods had minimal effects on rate measurements, but results were strongly dependent on tube brands. Differences in tube performance were observed consistently in comparisons from a variety of freshwater and marine environments. Microcentrifuge tubes differed in protein retention with the consequence that estimates of leucine incorporation in a given sample could vary by as much as 60% depending on the tube used. There was no simple relationship between tube plastics or manufacturer and tube performance. We advise researchers to check the protein retention of tubes and to use the same brand of tube during field studies to minimize this potential source of variation.