Ultrasound-guidance outperforms the palpation technique for peripheral venous catheterisation in anaesthetised toddlers: a randomised study.

BACKGROUND: Traditional palpation technique for peripheral venous catheter (PVC) placement can be challenging. We aimed to compare the Dynamic Needle Tip Positioning (DNTP) ultrasound technique with the palpation technique for PVC placement in anaesthetised toddlers undergoing elective, low-risk procedures. METHODS: The study was a randomised, controlled, crossover study. Five operators applied both techniques for PVC on 50 children < 4 years. The primary endpoint was first attempt success rate. The secondary endpoints were: (1) overall success rate, (2) number of skin perforations, (3) number of needle redirections, (4) number of catheters used, (5) total time, (6) needle manipulation time, (7) distance to the nearest flexion crease, (8) anatomical region of catheterisation, (9) size of the catheters and (10) the effects of visibility, and palpability of the veins. RESULTS: The first attempt success rate and the overall success rate were significantly higher in the DNTP group (42/50 vs. 30/50, P = 0.029), (50/50 vs. 42/50, P = 0.008). Furthermore, a lower number of skin perforations (60 vs. 84, P = 0.013) and needle redirections (14 vs. 131, P < 0.001) and increased distance to the nearest flexion crease (P < 0.001) were seen in the DNTP group. There were no significant differences in number of catheters used (60 vs. 75 P = 0.050) or total time (P = 0.073), however, the needle manipulation time was longer in the DNTP group (P = 0.011). The success rate decreased with less visible and palpable veins in the palpation group (p = 0.006). CONCLUSION: Ultrasound-guidance outperforms the traditional palpation technique for peripheral venous catheterisation in anaesthetised toddlers undergoing elective, low-risk procedures.

Paediatric ECMO at low-volume paediatric cardiac centres in the Nordic countries.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a life-saving resource-intensive technology for patients with respiratory and/or circulatory failure. We aimed to evaluate outcome data from three Nordic paediatric centres comparing with data from the International Registry of the Extracorporeal Life Support Organization (ELSO) and selected high-volume single-centre studies. METHODS: One-hundred nineteen patients < 19 years from 2002 to 2012 were enrolled. Data on demographics and outcome were collected using a standardised registration form. Outcome data were compared with the ELSO registry and high-volume single-centre studies. RESULTS: Demographics, indications and diagnosis were similar to the ELSO register. Survival after ECMO was similar to outcome data from the ELSO register, apart from paediatric cardiac ECMO, where a significantly better survival to discharge was seen in the Nordic centres (68% vs. 49%; P = 0.03). Comparison with high-volume centres in the period after 2005 demonstrated a significantly better survival after cardiac ECMO in a single high-volume centre study, whereas four studies had significantly lower survival after cardiac ECMO. No significant difference was seen in children receiving respiratory ECMO in the Nordic centres and high-volume centres. CONCLUSIONS: Survival after ECMO in three low-volume Nordic centres demonstrated comparable outcome data with ELSO data and data from high-volume centres. We believe regular quality assurance surveys, as the present study, should be performed in order to maintain excellent therapy within the individual ECMO centres.

Virtual reality increases pressure pain threshold and lowers anxiety in children compared with control and non-immersive control-A randomized, crossover trial.

BACKGROUND: Virtual reality (VR) is a promising non-pharmacological pain intervention because it may not only distract but also modulate pain by immersing the user in a three-dimensional 360° alternate reality. In children, VR has been reported to reduce clinical pain and anxiety during medical procedures. However, the effect of immersive VR on pain and anxiety remains to be investigated in randomized controlled trials (RCT). The aim of the present crossover RCT was to assess the effect of VR on pressure pain threshold (PPT) and anxiety level measured with the modified Yale Preoperative Anxiety Scale (mYPAS) in children in a controlled experimental setting. METHODS: Seventy-two children (mean age 10.2 (6-14) years) were randomized to 24 sequences of four interventions (immersive VR Game, immersive VR video, tablet: 2D video and control: small talk). Outcome measures PPT, mYPAS and heart rate were assessed before and after each intervention. RESULTS: PPT increased significantly during VR game (PPTdiff): 136 kPa (CI 112; 161), p < 0.0001 and VR Video (PPTdiff): 122 kPa (CI 91; 153), p < 0.0001. Also, anxiety levels significantly decreased during both VR game (mYPASdiff: -7 points (-8 to -5), p < 0.0001) and VR video (mYPASdiff: -6 points (CI -7; -4), p < 0.0001). CONCLUSIONS: VR had a marked beneficial effect on PPT and anxiety compared with the control interventions: 2D video and small talk. Thus, immersive VR had a distinct modulatory effect on pain and anxiety in a well-controlled experimental setting. Immersive VR was effective and feasible in children and can act as a valid tool for non-pharmacological pain and anxiety management. SIGNIFICANCE: Paediatric immersive VR seems to be beneficial although well-controlled studies are pending. We investigated whether immersive VR can modulate children's threshold for pain and anxiety level in an experimental well-controlled setting. We document a modulatory pain threshold increase and anxiety level decrease compared with extensive control conditions. Paediatric immersive VR is effective, feasible and valid for non-pharmacological pain and anxiety management. All efforts to reach the goal that no child should experience pain or anxiety when exposed to medical procedures.

Tranexamic acid given intraoperatively reduces blood loss after total knee replacement: a randomized, controlled study.

BACKGROUND: Extensive blood loss in total knee replacement (TKR) surgery is well known and is associated with a high transfusion rate of allogenic blood. Tranexamic acid (TXA) has been shown to reduce blood loss by 50% in this patient group, but only in cases with a perioperative loss of 1400-1800 ml. This study was performed to see if TXA offers any advantages in knee replacement surgery with blood loss at 800 ml. METHODS: Thirty consecutive patients scheduled for TKR in spinal anesthesia with the use of a tourniquet, were randomized to TXA or non-TXA. Tranexamic acid 10 mg kg-1 was given at conclusion of surgery and again 3 h later. Blood loss was registered. RESULTS: Total blood loss was at all times significantly lower in the TXA group compared to the non-TXA group (409.7+/-174.9 ml vs. 761.7+/-313.1 ml; P<0.001). There were no differences in coagulation parameters. No patients in the TXA group had a blood transfusion vs. 13% in the non-TXA group (NS). No complications were registered in the two groups. CONCLUSION: We conclude that TXA significantly reduces blood loss after total knee replacement surgery.

Diameter and cross-sectional area relationship of the human main pulmonary artery. Evaluated by epicardial echocardiography.

Correct assessment of vessel cross-sectional area (CSA) is essential for reliable cardiac output (CO) measurements by means of pulsed Doppler echocardiography. In 23 patients who underwent coronary artery bypass grafting (CABG) the main pulmonary artery CSA and diameter changes were assessed by epicardial two-dimensional echocardiography using a 7.5 MHz cm2 transducer. Our data indicate that the shape of the pulmonary artery changes over time. Time averaged CSA ranged from 3.51 to 8.29 cm2 (mean 5.04 cm2; SD 1.3 cm2) and the distensibility varied from 13% to 33% (mean 23%; SD 5%). The limits of agreement for the CSA calculated from the most suitable diameter (when assuming vessel circularity) and the corresponding traced CSA (reference value) during peak systole were -0.16 +/- 0.56 cm2 (mean +/- 2SD). In this idealized set-up (not clinically implementable) the maximal discrepancy between the calculated and traced CSA was 12% and 17% during peak systole and diastole, respectively. Therefore, a potential error in CO determination is incurred if CSA is assessed from a single diameter.

Movement of pulmonary artery catheters.

Intraluminal movements of pulmonary artery catheters are seldom considered, although they may have a significant impact on flow measurement and safety. The purpose of this study was to document the movements of these catheters within the heart cycle, and to establish whether any patterns existed. We analyzed two-dimensional real time echocardiography cross-sectional images of the human pulmonary artery in 20 patients, plotting the position of the intra-arterial catheter frame-by-frame onto a standardized template. We found that movement of the catheter within the pulmonary artery occurred in a seemingly random pattern. There was no movement pattern to the inferior right of the vessel, an area known to have complex velocity profiles and erroneous velocity measurements. The catheter moved substantially throughout the heart cycle, occasionally quite close to the vessel wall. We observed significant movement of the pulmonary artery catheter throughout the heart cycle, without any predictable pattern. Although we did not specifically investigate the effect of these movements on cardiac output, they imply that intra-arterial Doppler flow measurements from the pulmonary artery may be inaccurate, since a stable catheter position, and hence, a sample volume, cannot be ensured. Further speculation can be made on the implications of these movements in regard to thermodilution cardiac output and safety.

Mechanisms of nonimmunological histamine and tryptase release from human cutaneous mast cells.

BACKGROUND: If mast cells are stimulated they release multiple mediators that delineate markers for immunologic and nonimmunologic reactions; histamine and tryptase are the two best known. Although histamine can be assayed in plasma, it is a nonspecific marker with a very short half-life. Tryptase has a longer half-life, but its release has not been proven to be specific for anaphylaxis. The authors investigated the mechanisms of nonimmunologic histamine release from human cutaneous mast cells to understand the mechanisms of mediator release and to determine whether tryptase was specific for allergic mediated activation. METHODS: Dispersed mast cell suspensions isolated from neonatal foreskins underwent challenge with vancomycin, calcium ionophore A23187, morphine, and atracurium, and histamine tryptase release was measured. The effects of calcium and magnesium, along with phospholipase C and phospholipase A2 inhibitors, also were investigated. RESULTS: Tryptase and histamine both were released by the known nonimmunologic stimuli (pharmacologic agents used in the current study; r2 = 0.6). Furthermore, vancomycin- and atracurium-induced histamine release was calcium dependent. Phospholipase C and phospholipase A2 inhibitors decreased vancomycin-induced histamine release, but not calcium ionophore A23187-induced release. CONCLUSIONS: Tryptase is not a specific marker of mast cell activation (ie., anaphylaxis), and signaling mechanisms for mast cell activation involve activation of phospholipase C and phospholipase A2 pathways that are also involved in other cellular activation mechanisms.

Functional remodelling and left ventricular dysfunction after repeated ischaemic episodes. A chronic experimental porcine model.

This experimental study was set up to investigate left ventricular function and remodelling after repeated ischaemic episodes using magnetic resonance imaging (MRI). A significant reduction in mortality due to coronary heart disease (CHD) has been explained by both a decline in the incidence of acute myocardial infarction (AMI) and an improved post-AMI survival rate, suggesting a change in the natural history of CHD. Experimental intracoronary microembolization can induce different ischaemic patterns and the functional impact of repeated ischaemic episodes different from occlusion of central epicardial arteries can be studied. In this study repeated intracoronary microembolizations were performed in 20 domestic pigs. After 129 d, MRI was performed for assessment of left ventricular volume, mass and wall stress. Six pigs underwent serial MRI at baseline, immediately after embolization and at the end of the observation period. Microembolizations induced acute myocardial infarct expansion and increased left ventricular wall stress preceding chronic remodelling. End systolic and end diastolic volumes increased from 15.1 +/- 2.7 cm3 to 41.3 +/- 11.5 cm 3 (p < 0.002), and from 52.0 +/- 6.7 cm3 to 81.1 +/- 9.2 cm3 (p < 0.0007), respectively. End systolic wall stress increased from and 17.5 +/- 2.7 to 29.7 +/- 6.2 N/m2 (p < 0.001). Left ventricular filling pressures and cardiac index were unchanged. Histological examination revealed a diffuse pattern of perivascular fibrosis covering 12 +/- 3% of the left ventricular wall. This study demonstrates that repeated ischaemic episodes different from confined regional myocardial infarctions induce acute infarct expansion and chronic left ventricular remodelling in pigs. Serial assessment of absolute left ventricular volumes and mass is important during acute/chronic remodelling.