Topical wound anaesthesia: efficacy to mitigate piglet castration pain.

OBJECTIVE: There is a critical need for safe and effective analgesic treatments to address pain resulting from surgical husbandry procedures in livestock. Piglet castration results in acute pain and stress to the animal; however, it is performed globally on millions of piglets annually, often without any analgesia what-so-ever. Tri-Solfen® (Animal Ethics Pty Ltd, Yarra Glen, Victoria, Australia) is a combination local anaesthetic and antiseptic formulation which, applied topically to wounds, has proven effective, and is registered for use to alleviate pain associated with castration (and other wounds) in lambs and calves in Australia and New Zealand. It is also reported to be effective to reduce pain in piglets following castration. DESIGN: This randomised, blinded, placebo-controlled study examined the safety and efficacy of the formulation, administered via an adapted wound instillation method, to control pain both during and following piglet castration. METHOD: Piglets received Tri-Solfen or placebo, instilled to the wound immediately following skin incision. A 30 s wait period was then observed prior to completing castration. Pain mitigation was assessed by grading nociceptive resistance movements and piglet vocal response during castration, as well as by grading response to mechanical sensory stimulation of the wound (von Frey and needlestick) following castration. RESULTS: There was a significant reduction in nociceptive motor and vocal response during castration and in response to mechanical sensory wound stimulation up to and including 2 h following castration. There were no adverse events. CONCLUSION: Administered via this method, Tri-Solfen is effective to mitigate acute peri-operative castration pain in piglets.

Intraoperative transoesophageal echocardiography for paediatric cardiac surgery--an audit of 200 cases.

We report out initial experience with intraoperative transoesophageal echocardiography (TOE) in 200 patients undergoing repair of congenital heart disease. Complications associated with probe insertion precluded a full study in 11 patients (5.5%) and included airway obstruction (n = 6), inability to pass the probe (n = 4) and vascular compression (n = 1). The preoperative diagnosis was confirmed by TOE in 176 of 189 cases (93%) with minor variances in 12 (6.3%) and one major variance (additional large muscular ventricular septal defect (VSD)). Unexpected abnormalities not diagnosed preoperatively were found at surgery in four cases (2%) and were all of trivial operative significance. Postoperative studies showed no residual defect in 96 (51%) and trivial or mild residual defects in 72 patients (38%). There were moderate or severe residual defects in 21 cases (11%). Ten cases (5.3%) returned to bypass for further surgery, with eight achieving complete or adequate amelioration. In six of the 10 cases, return to bypass was prompted by the TOE examination alone. There was one re-operation in the postoperative period for a VSD patch dehiscence. Routine TOE offers significant advantages in the management of patients undergoing repair of congenital heart disease, particularly in postoperative assessment. Careful monitoring of perfusion and ventilation is required, particularly during probe insertion in children weighing 5 kg or less.

Deoxygenated blood minimizes adherence of sonicated albumin microbubbles during cardioplegic arrest and after blood reperfusion: experimental and clinical observations with myocardial contrast echocardiography.

Both administration of cardioplegic solution and blood reperfusion result in endothelial dysfunction. The transit rate of albumin microbubbles during myocardial contrast echocardiography may reflect endothelial injury. Accordingly, we performed myocardial contrast echocardiography in 12 dogs undergoing cardiopulmonary bypass and measured the myocardial transit rate of microbubbles injected into the aortic root during delivery of cardioplegic solutions containing arterial and venous blood and delivery of pure crystalloid cardioplegic solution. The myocardial transit rate of 99mTc-labeled red blood cells was measured and perfusates were sampled for biochemical analysis at each stage. The microbubble transit rate was markedly prolonged during delivery of crystalloid cardioplegic solution and improved significantly during infusion of blood cardioplegic solution (p < 0.001); venous compared with arterial blood in the solution resulted in a greater rate (p < 0.001). The microbubble transit rate did not correlate with pH, oxygen tension or carbon dioxide tension values, or K+ concentration. The red blood cell transit rate remained constant regardless of the cardioplegic perfusate infused. Myocardial contrast echocardiography was also performed in 12 patients undergoing coronary artery bypass who underwent sequential arterial and venous reperfusion after cardioplegic arrest. The microbubble transit rate was faster with venous than arterial blood reperfusion (p = 0.01), although this gain was diminished when arterial blood reperfusion preceded venous blood reperfusion (p = 0.05). Our results indicate that endothelial dysfunction after cardioplegic arrest may be ameliorated by reperfusion with venous rather than arterial blood.

Echocardiographic assessment of aortic root dimensions in normal children based on measurement of a new ratio of aortic size independent of growth.

Two-dimensional echocardiography is commonly used as a method of monitoring aortic root dimensions in children with connective tissue disease. Measurements are usually standardized to body surface area (BSA) to account for growth. However, there are several theoretical and practical disadvantages to adopting this approach, and there has been little investigation of alternative methods of standardization. This study of 48 normal children and adolescents (age range 2 weeks to 23 years) was performed to determine the relation of 2-dimensional echocardiographic aortic root dimensions to indexes of body size and growth, and to examine a simple means of internally standardizing aortic root measurements to create an index of aortic root size independent of growth. Maximal diameters in the parasternal long-axis view were recorded at 4 levels: annulus, sinuses of Valsalva (SOV), supraaortic ridge (SAR), and ascending aorta (AAO). Ratios of aortic root size were created by internally standardizing aortic root diameters to aortic annular size. All diameters correlated closely with age, height, weight, and BSA (all r > 0.87). Linear regression in each case showed a significant positive slope (all p < 0.0001). The best predictor of aortic dimensions was height, with r values of 0.93 for annulus, SOV, and AAO, and 0.95 for SAR. Ratios of SOV/annulus, SAR/annulus, and AAO/annulus remained constant, with no correlation with age or any growth parameters. Mean values and 95% confidence limits were: SOV/annulus 1.37 (1.18-1.56); SAR/annulus 1.11 (0.95-1.28); and AAO/annulus 1.16 (0.97-1.35). Standardization to height, or the use of internally standardized aortic root ratios, provides a simple and accurate alternative to standardization to BSA for assessing aortic root dimensions in normal growing children.