Pain During Venous Cannulation.

BACKGROUND: The pain of venous puncture for the cannulation of peripheral veins is disturbing to many patients. This is the first clinical trial of the efficacy of local anesthesia in comparison to placebo (no pretreatment) in a control group, as a function of the size of the cannula. METHODS: A randomized, controlled trial of fully factorial design was performed to study pain during venipuncture after local anesthesia either with intra - dermally injected lidocaine or with a vapocoolant spray, in comparison to placebo. A standardized protocol was used for structured communication with the patient to provide the greatest feasible degree of patient blinding (trial registration number DRKS00010155). The primary endpoints were the subjective discomfort of the patient during preparation and puncture of a vein of the dorsum of the hand, assessed on a numerical rating scale (NRS) from 0 (no discomfort) to 10 (unbearable discomfort), and the rate of unsuccessful puncture. RESULTS: The intention-to-treat analysis of all 450 patients revealed that the reported degree of pain during venipuncture depended to a large extent on the caliber of the chosen venous cannula. For a 17-gauge (17G) cannula, both the vapocoolant spray (NRS = 2.6 ± 1.3) and lidocaine (NRS = 3.5 ± 2.2) lessened the discomfort due to venipuncture compared to control treatment (5.0 ± 1.5). The effect of vapocoolant spray compared to the control was both clinically relevant and statistically significant (p < 0.0001). When a smaller 20G cannula was used, however, vapocoolant spray improved discomfort by only 0.8 NRS points, which, though still statistically significant (p = 0.0056), was no longer clinically relevant. The rate of unsuccessful puncture was higher after lidocaine pretreatment (12.7%) than after either vapocoolant spray (4.7%; p = 0.0066) or no pretreatment (4.0%; p = 0.0014). CONCLUSION: Local anesthesia can be recommended before venipuncture only if a large cannula is used (e.g., ≥ 17G). Vapocoolant spray may be at least as useful as lidocaine injection; it prevents pain to a similar extent and is associated with a lower rate of unsuccessful puncture.

Early Clinical Experience with a Newly Designed Interlocking Nail System-Targon(®) Vet.

OBJECTIVE: To describe early clinical experience with a newly designed interlocking nail system (Targon(®) Vet) in diaphyseal fractures in cats and small dogs. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned cats (n=49) and dogs (n=8). METHODS: Fifty-seven consecutive cases (49 cats, 8 dogs) with 60 long bone fractures were included in the study. Follow-up radiographs were scheduled at 4 and 8 weeks and again 6 months postoperatively. The end point for each case was determined radiographically by a healed fracture. Complications were defined as minor or major. Clinical outcome was subjectively assessed by a full orthopedic examination and follow-up radiographs. Descriptive data are reported. RESULTS: Median age of cats was 18 months (range, 3-220 months) and of dogs was 28 months (range, 7-115 months). Median body weight was 3.7 kg (range, 1.67-8.41 kg) for cats and 8.15 kg (range, 2.68-13.6 kg) for dogs. Median radiographic follow-up was 16 weeks. All fractures with follow-up radiographs available (n=46) were healed with no infections reported. A total of 12 postoperative complications occurred: 3 minor (slippage of the locking screws) and 9 major (5 femoral-irritation of the sciatic nerve, stress protection, fracture because of a missed fissure, femoral neck fracture, intra-operative revision with a rod and plate; 4 tibial-3 with protrusion of the distal locking screw through the skin and 1 with in-growth of the intramedullary nail). CONCLUSION: Implantation of the Targon(®) Vet System was feasible in all cases. It provides an alternative system for diaphyseal fracture repair in cats and small dogs.

Coexpression and spatial association of nicotinic acetylcholine receptor subunits alpha7 and alpha10 in rat sympathetic neurons.

Fast excitatory synaptic transmission in sympathetic ganglia is mediated by nicotinic acetylcholine receptors (nAChRs). Although it is known that the nAChR alpha7-subunit occurs in sympathetic ganglia, the expression of the recently cloned subunit alpha10 (Elgoyhen et al., 2001; Lustig et al., 2001; Sgard et al., 2002) has not been analyzed. Until now, functional receptors containing alpha10-subunits have been found only in combination with alpha9-subunits (Elgoyhen et al., 2001; Lustig et al., 2001; Sgard et al., 2002). The alpha9-subunit exhibits a restricted expression pattern, whereas the alpha10-subunit is expressed more widely. This broad distribution resembles more closely that known for subunit alpha7 than for subunit alpha9. On this background, we investigated the distribution of nAChR subunits alpha7, alpha9, and alpha10 in rat sympathetic ganglia and studied a possible interaction between subunit alpha7 and potential partners by double-labeling immunofluorescence and fluorescence resonance energy transfer (FRET) (Kam et al., 1995; Jares-Erijman and Jovin, 2003).

Nicotinic acetylcholine receptors containing subunits alpha3 and alpha5 in rat nociceptive dorsal root ganglion neurons.

Nociceptive primary afferent neurons carry nicotinic acetylcholine receptors (nAChRs). Using RTPCR, mRNAs for all alpha-subunits have been identified in rat dorsal root ganglia (DRG) (Genzen et al., 2001; Lips et al., 2002), but the responses of nociceptive neurons to nicotine are not uniform and the cellular distribution of nAChRs within DRG, in general, and among functionally different subtypes of primary afferent neurons, in particular, are only partially resolved (Rau et al., 2005). These diverse actions might suggest the presence of various nAChR isoforms that are operative under different conditions. The present study was aimed to extend previous studies on nAChRs that contain subunits alpha4, alpha7, and alpha10 in providing data for alpha3- and alpha5-subunit-containing nAChRs (Haberberger et al., 2004; Papadopolou et al., 2004). To this end, calcium-imaging and double-labeling immunofluorescence with nAChR alpha-subunit-specific antibodies, in combination with markers for nociceptive neurons (TRPV1, I-B4), were applied.