Haematoma and abscess after neuraxial anaesthesia: a review of 647 cases.

Although rare, spinal haematoma and abscess after central neuraxial blocks may cause severe permanent neurological injury. Optimal treatment and outcome remain unclear. In order to identify possible predisposing patient characteristics and describe the ensuing clinical course, we searched Medline, Embase, and the Cochrane Library for reports of spinal haematomas and abscesses associated with central neuraxial blocks. Extracted data included patient characteristics, symptoms, treatment, and outcome. We analysed 409 reports, including 647 patients (387 patients with spinal haematoma and 260 patients with spinal abscess). Spinal haematoma and abscess occurred predominantly after epidural anaesthesia (58% and 83%, respectively). Neurological recovery was correlated with the severity of initial neurological deficit. When decompression of spinal haematoma was delayed for >12 h after clinical diagnosis, neurological outcome was worse compared with earlier decompression (odds ratio 4.5, 95% confidence interval 2.1-9.9, P<0.001, n=163). After spinal haematoma, 47% of published patients had full recovery, 28% had partial recovery, and in 25% no recovery was observed. Good outcome after conservative management was observed in patients with mild symptoms or with spontaneous recovery during the diagnostic and therapeutic workup. After spinal abscess, 68% of reported patients recovered fully, 21% showed partial recovery, and no recovery was reported in 11%. Persistent neurological symptoms after spinal haematoma and abscess are common and correlate with the severity of initial neurological deficit. Neurological outcome seems worse when decompressive surgery of haematoma is delayed. Notwithstanding the considerable risk of selection bias and publication bias, conservative management may be feasible in patients with mild symptoms or spontaneous recovery.

[Multidisciplinary treatment of orofacial pain]. / Multidisciplinaire behandeling van aangezichtspijn.

The diagnosis and treatment of orofacial pain can be complex. The differential diagnosis is very extensive. Therefore, multidisciplinary diagnosis and treatment are often indicated. The diagnosis of chronic pain also entails the investigation of psychological factors. This is because psychological problems can play a role in the chronification of pain, but they can also be a consequence of chronic pain. Patients with persistent orofacial complaints should be seen by a medical team consisting of an oral and maxillofacial surgeon, a neurologist, an anaesthesiologist/pain specialist, a dentist-gnathologist, an orofacial physical therapist, and a psychologist or psychiatrist specialising in orofacial pain. Treatment options should be discussed, taking into account literature concerning their effectiveness. The general conclusion is that much research remains to be done into the causes of, and treatments for, orofacial pain.

Methadone is superior to fentanyl in treating neuropathic pain in patients with head-and-neck cancer.

BACKGROUND: Cancer pain is still inadequately treated in up to 60% of cancer patients. Based on the additional effect on the N-Methyl-d-Aspartate receptor, we expected that methadone (Met) could provide better pain relief than fentanyl (Fen) in cancer pain with a neuropathic pain component. METHODS: A randomised controlled trial was performed with 52 strong opioids naive patients with head-and-neck cancer with substantial pain (pain Numerical Rating Scale [NRS] > 4) and a neuropathic pain component (Douleur Neuropathique [DN4] > 4). Twenty-six patients were treated with Met and 26 with Fen. Patients were evaluated at 1, 3 and 5 weeks. The primary outcomes were reduction in average pain, clinical success (defined as 50% average pain decrease) and reduction in pain interference. Secondary outcomes were global perceived effect (GPE) and side-effects. FINDINGS: Reduction in NRS was higher with the use of Met at 1, 3 and 5 weeks (pain change 2.9, 3.1 and 3.1) compared to Fen (1.4, 1.7 and 2.0). This difference was significant at 1 (p = 0.011) and at 3 weeks (p = 0.03). Clinical success (>50% improvement) was higher with Met at 1 week (15% versus 50%, p = 0.012). The change in pain interference, the GPE and side-effect profile were not significantly different between the groups. INTERPRETATION: This is the first study to compare the effects of Met to Fen in cancer patients with a neuropathic pain component. Based on the results of this study, Met should be considered in the treatment of oncological pain with a neuropathic component.

Two-dimensional temperature measurements in a technical combustor with laser Rayleigh scattering.

Application of the two-dimensional laser Rayleigh technique to the investigation of a large-scale industrial combustor is reported for the first time to our knowledge. Two-dimensional laser Rayleigh scattering was used to perform quantitative measurements of the temperature fields in different downstream positions of a 150-kW industrial, premixed, turbulent low-emission swirl combustor. Because of the possible interferences of the Rayleigh signal with Mie scattering and laser reflections of the burner components, some minor modifications of the design of the combustor and its gas supply were necessary. This was done without changing the basic characteristics of the burner. The quantitative and instantaneous character of the collected data allows calculation of ensemble-averaged temperature distributions and analysis of the flame structure in the turbulent combustion field. The measured temperature distribution confirms that the flame is stabilized by a central recirculation zone.

Quantitative two-photon LIF imaging of carbon monoxide in combustion gases.

Two-dimensional imaging of CO concentration in combustion gases is demonstrated using two-photonexcited planar laser-induced fluorescence. A quantitative model is presented for the simultaneous twophoton excitation of several rotational transitions of the B(1)Sigma(+) ? X(1)Sigma(+) system and the subsequent visible fluorescence (B(1)Sigma(+) ? A(1)Pi). The model is verified by comparison of predicted and measured excitation spectra and of temperature-corrected relative fluorescence measurements to standard probe measurements of the center line CO distribution in a CO-air diffusion flame. In addition, CO imaging experiments in a premixed methane-air flame indicate the production of C(2) by laser photodissociation of acetylene.

Two-photon digital imaging of CO in combustion flows using planar laser-induced fluorescence.

Two-dimensional imaging of CO distributions in combustion gases is demonstrated using planar laser-induced fluorescence. The illumination technique is based on the combination of a nonlinear absorption scheme, in which two photons at 230.1 nm excite several rotational transitions of the B (1)Sigma(+) ? X(1)Sigma(+) system, and the use of an ultraviolet multipass cell for producing the laser sheet. The subsequent visible fluorescence (B(1)Sigma(+) ? A (1)Pi) is imaged onto an intensified two-dimensional photodiode array. Experimental results are presented for carbon monoxide-air and methane-air flames.

Flame-temperature measurements using the Rayleigh scattering photon-correlation technique.

The utilization of a Rayleigh scattering photon-correlation technique for flame-temperature measurements is presented. Such measurements are reported for the first time to our knowledge and make use of a digital correlator that permits the determination of temporally varying temperature structures (e.g., coherence structures) for extremely low scattering intensities. The application of low-power cw lasers (e.g., He-Ne lasers) seems also to be possible for the investigation of fast processes in the kilohertz domain. In particle-laden flames the influences of Mie scatterers (e.g., soot particles) can be separated by the different time behavior, which, for those scatterers, is governed by the flow velocity.

Stable isotope ratiometer-multiple ion detector unit for quantitative and qualitative stable isotope studies by gas chromatography-mass spectrometry.

We have designed and constructed a stable isotope ratiometer-multiple ion detector unit, which can drive existing chromatograph-quadrupole or magnetic sector mass gas spectrometers to monitor up to six ions in turn. Each of the three pairs of ions can be selected for quantitation; thus three different or successive components can be analyzed in a single gas-chromatographic run. A background subtraction option permits the ion intensity in the absence of sample to be subtracted automatically during sample measurement. Displays of accumulated counts and isotope ratio are updated twice per second during the measurement and can be printed out at is conclusion. All six ions can be monitored in the analog mode by parallel outputs to a multipen recorder. Experience gained in the construction of this prototype indicates that such units could be commercially available for $10 000, or about a third to a sixth of the cost of even an inexpensive computer system.