Early ultrasonographic detection of low-volume intraneural injection.

BACKGROUND: Intraneural injection of local anaesthetic agents carries a risk of neurological complications. Early detection of intraneural needle-tip position is very important in the initial phase of injection. Ultrasound (US) characteristics for real-time detection of intraneural injections have been described, but only for relatively large volumes (5-40 ml). This study assesses the reliability of various US criteria to detect early low volume (0.5 ml) intraneural injections. Intraneural deposition of an injected dye was confirmed by cryomicrotomy. METHODS: In nine unembalmed human cadavers, 0.5 ml methylene blue was injected intraneurally into the supraclavicular brachial plexus and subgluteal sciatic nerve on both sides. The sites of injection were subsequently removed en bloc. Consecutive cryomicrotomy cross-sections with a 50 µm interval were obtained to assess intraneural presence of the injectate. Two independent experts separately reviewed US video clips of the injections and scored each US criterion. RESULTS: Of the 36 injections, cryomicrotome cross-sections showed intraneural staining in 33 and extraneural staining in three. The best US criterion was expansion of the nerve cross-sectional surface area together with a change in echogenicity. It was observed in 35 injections, including two false positives. There was one true negative. Test precision was 94% [95% confidence interval (CI), 87-100%]. The mean increase in surface area was 8.7% (95% CI, 5.6-11.9). CONCLUSIONS: Reliable detection of early low-volume intraneural injection using US is possible using expansion of the cross-sectional surface area of the nerve together with a change in echogenicity as markers.

Hand-hygiene practices in the operating theatre: an observational study.

BACKGROUND: The current prevalence of healthcare-associated infections (HCAIs) is a major public health concern. Patient contact in the operating theatre (OT) can contribute to HCAI via microbial contamination. The application of hand hygiene is effective in reducing infection rates. Limited data are available on adherence to hand-hygiene guidelines by OT staff. METHODS: Covert direct observations of OT staff at an academic medical centre were performed by a single, trained observer. The primary outcome was the frequency of hand-hygiene application by OT staff, including anaesthesiologists, anaesthesia nurses, surgeons, surgical nurses, and medical students. 'Sterile' scrubbed staff members were excluded. The following hand-hygiene opportunities were monitored: (i) entering or leaving the OT; and (ii) before patient contact. Furthermore, the frequency of 'potential contamination' was recorded (touching OT implements after contact with patient/patient body fluids without the subsequent application of hand hygiene). We recorded non-surgical glove usage for invasive procedures, for example, intubation or insertion of intravascular devices. Finally, we collected qualitative data on incentives for hand hygiene. RESULTS: A total of 28 operations were observed (60 h of observations). On average, 0.14 hand-hygiene applications per hour per staff member were witnessed. Upon entering or leaving the OT, hand hygiene was performed in 2% (7/363) and 8% (28/333) of opportunities. CONCLUSIONS: Frequent interactions between patient, staff, and OT environment were observed. Adherence to hand-hygiene guidelines by OT staff was extremely low. This potentially exposes patients to microbial transmission, HCAIs, and patient harm.