Handwashing practice and policy variability when caring for central venous catheters in paediatric intensive care.

It has been estimated that there may be as many as 150,000 healthcare associated infections (HCAI) in Australia each year, contributing to 7,000 deaths, many of which could be prevented through the implementation of appropriate infection control practices. Contact with contaminated hands is a primary source of HCAI. Intensive care staff have been identified as one of the least adherent groups of health care professionals with handwashing; they are less likely to practise hand antisepsis before invasive procedures than staff working in other patient care specialties. The study examined the self-reported clean and aseptic handwashing practices of nurses working in paediatric intensive care units (PICUs) across Australia and New Zealand, the patterns in variation between nurses' reported handwashing practices and the local policies, and patterns in the duration of procedural handwashing for specific procedures. A survey was undertaken in 2001 in which participating tertiary paediatric hospitals provided copies of their infection control policies pertaining to central venous catheter (CVC) management; five nurses on each unit were asked to provide information in relation to their handwashing practices. Seven hospitals agreed to participate and 30 nurses completed the survey. The study found an enormous level of variation among and between nurses' reported practices and local policies. This variation extended across all aspects of handwashing practices - duration and extent of handwash, type of solution and drying method used. The rigour of handwashing varied according to the procedure undertaken, with some evidence that nurses made their own risk assessments based on the proximity of the procedure to the patient. In conclusion, this study's findings substantiate the need for standardisation of practice in line with the current Centers for Disease Control and Prevention Guidelines, including the introduction of alcohol handrub.     

Central venous access and handwashing: variability in policies and practices

This study examined variability in handwashing policy between hospitals, variability in handwashing practices in nurses and how practice differed from policy in tertiary paediatric hospitals in Australia and New Zealand. Eight of the possible nine major paediatric hospitals provided a copy of their handwashing and/or central venous access device (CVAD) policies, and 67 nurses completed a survey on their handwashing practices associated with CVAD management. A high degree of variability was found in relation to all the questions posed in the study. There was little consistency between policies and little agreement between policies and clinical practice, with many nurses washing for longer than required by policy. Rigour of handwashing also varied according to the procedure undertaken and the type of CVAD with activities undertaken farther from the insertion site of the device more likely to be performed using a clean rather than an aseptic handwashing technique. As both patients and nursing staff move within and between hospitals, a uniform and evidence-based approach to handwashing is highly desirable.     

Effects of ovariectomy on bone turnover,porosity, and biomechanical properties in ovine compact bone 12 months postsurgery

Compact bone makes up approximately 80% of the human skeleton by mass; but there are little data available on the effects of increased bone turnover on compact bone mechanical and material properties. This study addresses this question by measuring intracortical remodeling, resorption cavity number, and porosity in an ovariectomized (OVX) sheep model, and measures changes in biomechanical properties. Thirty‐eight sheep were divided into two groups. Group 1 were controls (n = 19), and Group 2 were ovariectomized (OVX; n = 19). Fluorochrome dyes were administered intravenously to both groups at five time points over 12 months post‐OVX to label sites of bone turnover. At 12 months post‐OVX all animals were euthanized. Samples were harvested from the left metatarsal and were analyzed for intracortical bone turnover at five time points, the number of resorption cavities, and the level of intracortical porosity. The effects of these parameters on bone biomechanical properties were then measured. Bone turnover was increased in the OVX group at 6, 9, and 12 months (p < 0.05). Resorption was also higher in the OVX group at 12 months (p < 0.05). Furthermore, porosity was significantly increased in the OVX group at 12 months (p < 0.05). Stiffness and yield strength were reduced in the OVX group compared to controls (p = 0.05). Ultimate compressive strength and work to fracture did not differ between groups. These findings provide new insights into the mechanisms and effects of increased bone turnover on bone material and microstructural properties. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:303–309, 2009     

Development of a home cage locomotor tracking system capable of detecting the stimulant and sedative properties of drugs in rats

The advent of automated locomotor activity methodologies has been extremely useful in removing the subjectivity and bias out of measuring this parameter in rodents. However, many of these behavioural studies are still conducted in novel environments, rather than in ones that the animals are familiar with, such as their home cage. The purpose of the present series of experiments was to develop an automated home cage tracking (HCT) profile using EthoVision software and assessing the acute effects of stimulant (amphetamine and methamphetamine, 0-5 mg/kg, sc) and sedative (diazepam, 0-20 mg/kg, sc and chlordiazepoxide, 0-50 mg/kg sc) drugs in this apparatus. Young adult male Sprague-Dawley rats were used, and the home cage locomotor activity was recorded for 11-60 min following administration (n=4 per group). For amphetamine and methamphetamine, a dose-dependent increase in home cage activity was evident for both drugs, with a plateau, followed by reduction at higher doses. Methamphetamine was more potent, whereas amphetamine produced greater maximal responses. Both diazepam and chlordiazepoxide dose-dependently reduced locomotor activity, with diazepam exhibiting a greater potency and having stronger sedative effects than chlordiazepoxide. Three doses of each drug were selected at the 31-40 min time period following administration, and compared to open field responses. Diazepam, chlordiazepoxide and amphetamine did not produce significant changes in the open field, whilst methamphetamine produced a significant increase in the 2.5 mg/kg group. In conclusion, these studies have successfully developed a sensitive HCT methodology that has been validated using drugs with stimulant and sedative properties in the same test conditions, with relatively small numbers of animals required to produce statistically significant results. It has proven superior to the open field investigations in allowing dose-response effects to be observed over a relatively short observation period (i.e. 10 min) for both stimulants and sedatives. In addition, the HCT system can determine differences in potency and efficacy between drugs of a similar chemical class.     

The New AASM Criteria for Scoring Hypopneas: Impact on the Apnea Hypopnea Index

Study Objectives:

To compare apnea-hypopnea indices (AHIs) derived using 3 standard hypopnea definitions published by the American Academy of Sleep Medicine (AASM); and to examine the impact of hypopnea definition differences on the measured prevalence of obstructive sleep apnea (OSA).

Design:

Retrospective review of previously scored in-laboratory polysomnography (PSG).

Setting:

Two tertiary-hospital clinical sleep laboratories.

Patients or Participants:

328 consecutive patients investigated for OSA during a 3-month period.

Interventions:

N/A

Measurements and Results:

AHIs were originally calculated using previous AASM hypopnea scoring criteria (AHI_Chicago), requiring either > 50% airflow reduction or a lesser airflow reduction with associated > 3% oxygen desaturation or arousal. AHIs using the “recommended” (AHI_Rec) and the “alternative” (AHI_Alt) hypopnea definitions of the AASM Manual for Scoring of Sleep and Associated Events were then derived in separate passes of the previously scored data. In this process, hypopneas that did not satisfy the stricter hypopnea definition criteria were removed. For AHI_Rec, hypopneas were required to have ≥ 30% airflow reduction and ≥ 4% desaturation; and for AHI_Alt, hypopneas were required to have ≥ 50% airflow reduction and ≥ 3% desaturation or arousal. The median AHI_Rec was approximately 30% of the median AHI_Chicago, whereas the median AHI_Alt was approximately 60% of the AHI_Chicago, with large, AHI-dependent, patient-specific differences observed. Equivalent cut-points for AHI_Rec and AHI_Alt compared to AHI_Chicago cut-points of 5, 15, and 30/h were established with receiver operator curves (ROC). These cut-points were also approximately 30% of AHI_Chicago using AHI_Rec and 60% of AHI_Chicago using AHI_Alt. Failure to adjust cut-points for the new criteria would result in approximately 40% of patients previously classified as positive for OSA using AHI_Chicago being negative using AHI_Rec and 25% being negative using AHI_Alt.

Conclusions:

This study demonstrates that using different published standard hypopnea definitions leads to marked differences in AHI. These results provide insight to clinicians and researchers in interpreting results obtained using different published standard hypopnea definitions, and they suggest that consideration should be given to revising the current scoring recommendations to include a single standardized hypopnea definition.

Citation:

Ruehland WR; Rochford PD; O''Donoghue FJ; Pierce RJ; Singh P; Thornton AT. The new AASM criteria for scoring hypopneas: Impact on the apnea hypopnea index. SLEEP 2009;32(2):150–157.