Anesthesia and the developing brain: a way forward for clinical research

It is now well established that many general anesthetics have a variety of effects on the developing brain in animal models. In contrast, human cohort studies show mixed evidence for any association between neurobehavioural outcome and anesthesia exposure in early childhood. In spite of large volumes of research, it remains very unclear if the animal studies have any clinical relevance; or indeed how, or if, clinical practice needs to be altered. Answering these questions is of great importance given the huge numbers of young children exposed to general anesthetics. A recent meeting in Genoa brought together researchers and clinicians to map a path forward for future clinical studies. This paper describes these discussions and conclusions. It was agreed that there is a need for large, detailed, prospective, observational studies, and for carefully designed trials. It may be impossible to design or conduct a single study to completely exclude the possibility that anesthetics can, under certain circumstances, produce long‐term neurobehavioural changes in humans; however , observational studies will improve our understanding of which children are at greatest risk, and may also suggest potential underlying etiologies, and clinical trials will provide the strongest evidence to test the effectiveness of different strategies or anesthetic regimens with respect to better neurobehavioral outcome.     

Color Doppler ultrasound for monitoring free flaps in the head and neck region

The use of microvascular free flaps has become established as a very reliable reconstructive technique following tumor surgery or trauma in the head and neck region. Occasionally, flap compromise may occur which will require immediate re-exploration. Early diagnosis of vascular insufficiency is essential. Clinical signs are not always reliable. Numerous systems have been described for monitoring the viability of microsurgical free flaps. The authors consider that color Doppler ultrasound is one of the most useful diagnostic tools. Three cases are reviewed in which this technique aided the decision whether re-exploration was necessary.     

The corner frequencies of the ECG amplifier for heart rate variability analysis

Heart rate variability (HRV) analysis is considered a popular method both in clinical and research fields. However, several ignored technical artifacts may falsify its measurements. The current study investigates the effects of corner frequencies of the ECG amplifier on the precision of RR-interval detection. Clear or noise-corrupted ECG records with predefined parameters consisting of 21 cycles were generated, played back through analog filters and data-logged on a Pentium-based computer with a DaqBoard2000 data acquisition card. 0.1-10 Hz second-order high pass and 20-100 Hz fourth-order low pass Bessel and Butterworth filters were used. The RR-intervals were measured between seven reference points of the ventricular complexes before and after filtering. High and low pass at every frequency cutoff and with both filter types results in correct RR-intervals within 1 ms error. However, a lower cutoff below 1 Hz is needed to maintain ECG morphology. AC interference or Gaussian random noise can falsify the measured RR-intervals up to 16 or 34 ms, respectively. These errors may be reduced to 1-4 ms with appropriate low pass filters. A frequency range of 0.5-20 Hz for the ECG amplifier can be sufficient for HRV analysis reducing the errors from AC interference or random noise.     

Peripherally induced resiniferatoxin analgesia

Selective blockade of nociceptive pathways represents a mechanism-based approach that has attracted a large variety of pharmacological and molecular investigations. A potential site for selective intervention is the primary afferent nociceptive nerve terminal. Binding of resiniferatoxin (RTX) to the vanilloid-1 receptor (VR1) stimulates and then inactivates heat and vanilloid-responsive nerve endings involved in heat and inflammatory pain signaling which can progress to localized degeneration of the peripheral ending followed by regeneration. Application of RTX directly to peripheral nerve endings produces a long term, reversible attenuation of nociceptive transmission. Heat hyperalgesia and mechanical allodynia were assessed prior to injection of RTX into the hindpaw (baseline) and at acute (minutes-hours) and more chronic (days-weeks) times after injection. Acutely, an inverse dose-to-pain response (guarding, licking) for RTX (0.0625-2.0 microg) occurs, followed by selective attenuation of peripheral pain transmission. Thermal nociception was decreased in a concentration-dependent fashion and lasted up to 21 days, without impairing motor function. Administration of RTX blocked both inflammation-induced hyperalgesia and spinal c-Fos induction. The results demonstrate the efficacy and therapeutic potential of reversible, peripheral C-fiber 'inactivation' for intermediate duration pain control.     

Harmful and protective roles of neutrophils in sepsis

The current studies demonstrate protective and harmful effects of neutrophils (PMN) during experimental sepsis after cecal ligation and puncture (CLP). It is known that CLP induces signaling defects in blood PMN. When PMN were depleted 12 h after CLP, there were dramatic reductions in levels of bacteremia, evidence for reduced liver and renal dysfunction, sharp reductions in serum levels of cytokines (IL-1beta, IL-6, IL-10, TNF-alpha, and IL-2), and improved survival. In contrast, PMN depletion before CLP resulted in substantial increases in bacteremia and no evidence for attenuation of liver and renal failure dysfunction. These data suggest that at the onset of sepsis, PMN are important in regulating the levels of bacteremia, whereas after the onset of sepsis, as they lose innate immune functions, their presence is associated with higher levels of bacteremia and intensified organ dysfunction.     

Essential role of using virtual pyeloscopy in the diagnosis of small satellite renal pelvic tumour in solitary kidney patient

Virtual pyeloscopy (VP) plays an important role in the organ-sparing nephroscopic tumour resection and traditional pole resection, especially when a fibreoptic ureteroscopic examination cannot be performed. A 67-year-old man developed macroscopic hematuria. Abdominal computed tomography (CT) and cystoscopy revealed a lower calix renal stone and a 20-mm lower pyelon mass suggesting transitional cell cancer. An additional small satellite lesion in the pelvico-ureteral junction was supposedly present. Three-phase MultiDetector CT with VP showed a solitary 3 to 4-mm renal pelvic lesion beyond the known calix stone and lower pole mass. In our case, VP played an important role in the organ-sparing nephroscopic tumour resection and traditional pole resection.