Ultrasonographic anatomic variations of the major veins in paediatric patients.

BACKGROUND: The aim of our study was to describe the anatomic relationships in internal jugular (IJV), subclavian (SCV), and femoral (FV) vein sites. METHODS: One hundred and forty-two children had a two-dimensional (2D) ultrasound (US) evaluation of IJV, SCV, and FV sites. They were enrolled according to their age: 0-1 month old (n=9), 1 month old to 2 yr old (n=61), 2-6 yr old (n=22), 6-12 yr old (n=32), and 12-18 yr old (n=18). RESULTS: We found about 7.7% variation for the IJV. The most common anatomic variations were a lateral (nine children) or anterior (nine children) position of the IJV to the carotid artery. Regardless of the age category, about 9.8% of the anatomic variations were found for the FV. The most common anatomic variation in our study was that the FV ran anteromedially to the femoral artery (17 children). Anatomic variation of the SCV, regardless of age category, was about 7.4%. The most common anatomic variation was the SCV, which ran medially (10 children) to the subclavian artery. CONCLUSIONS: The relevant percentages of anatomic variations obtained for all these areas support at least a systematic US screening before attempting to obtain central venous access, ideally using a US-guided technique.

Predicting fluid responsiveness in mechanically ventilated children under general anaesthesia using dynamic parameters and transthoracic echocardiography.

BACKGROUND: Dynamic variables are accurate predictors of fluid responsiveness in adults undergoing mechanical ventilation. They can be determined using respiratory variation in aortic flow peak velocity (▵Vpeak), arterial pulse pressure [▵PP and pulse pressure variation (PPV)], or plethysmographic waveform amplitude [▵POP and pleth variability index (PVI)]. These indices have not been validated in children. We studied the ability of these variables to predict fluid responsiveness in mechanically ventilated children. METHODS: All results are expressed as median [median absolute deviation (MAD)]. Thirty mechanically ventilated children were studied after undergoing general anaesthesia. Mechanical ventilation was maintained with a tidal volume of 10 ml kg(-1) of body weight. ▵PP, PPV, ▵POP, PVI, ▵Vpeak, and aortic velocity-time integral were recorded before and after volume expansion (VE). Patients were considered to be responders to VE when the aortic velocity-time integral increased more than 15% after VE. RESULTS: VE induced significant changes in ▵PP [13 (MAD 4) to 9 (5)%], PPV [15 (5) to 9 (5)%], ▵POP [15 (10) to 10 (6)%], PVI [13 (6) to 8 (5)%], and ▵Vpeak [16 (9) to 8 (3)%] (P<0.05 for all). Differences in ▵PP, ▵POP, PPV, and PVI did not reach statistical significance. Only ▵Vpeak was significantly different between responders (R) and non-responders (NR) to VE [22 (3) vs 7 (1)%, respectively; P<0.001]. The threshold ▵Vpeak value of 10% allowed discrimination between R and NR. CONCLUSIONS: In this study, ▵Vpeak was the most appropriate variable to predict fluid responsiveness.

[Design and evaluation of the quality of information written for scanner and magnetic resonance imaging in neuropediatrics]. / Conception et évaluation de la qualité d'une information écrite sur le scanner et l'imagerie par résonance magnétique en neuropédiatrie.

INTRODUCTION: We designed written information concerning two medical imaging techniques: the computed tomography scanner and the magnetic resonance imaging (MRI), and we evaluated the quality of the information in particular its readability. METHODS: Written information concerning scanner and MRI were elaborate starting from a reference frame based on a lexicon of the good practices. The written information sheets were initially reviewed by eight doctors, 45 nurses and by 26 couples of parents of hospitalized children, and finally by the communication and juridical services of our hospital. They were asked to improve the lexico-syntactic readability in order to increase the comprehension of the written information. Seventy-two couples of parents of hospitalized children who had not taken part of the protocol before evaluated the final version of the documents. The quality of the documents was evaluated using the scores of readability of Flesch and the Flesch-Kincaid, and a questionnaire of comprehension, managed before and after the delivery of written information. RESULTS: A total of 144 persons participated in the study. The number of right answers after reading written information increased by 38 % and by 35 % for the scanner and MRI information's respectively. Flesch and Flesch-Kincaid scores were not improved in the revised version of the written information compared to the first version. CONCLUSION: Although readability scores for information sheets were low, our results suggest that they brought information, which contributed to a better understanding of these two medical imaging techniques by parents.

[Ondansetron: a meta-analysis on its efficacy to prevent postoperative nausea and vomiting after craniotomy in adults and children]. / Méta-analyse : ondansétron en prophylaxie des nausées et vomissements postopératoires chez l'adulte et l'enfant après craniotomie.

OBJECTIVE: To justify the use of ondansetron as a preventive treatment for postoperative nausea and vomiting (PONV) of adults and children in neurosurgery. STUDY DESIGN: Meta-analysis. PATIENTS AND METHODS: Six published, randomized, double-blinded, placebo-controlled trials were selected to study the efficacy of ondansetron on PONV in adults undergoing craniotomy. Similarly, three studies were selected in children. The treated adults received 4 or 8 mg of ondansetron during the peroperative period. As for children, they were given a repeated dose of 0.15 mg/kg of ondansetron. The emetic episodes noted for 24 hours in children and until 48 hours in adults were analyzed. The results were presented as relative risks (RR) following a fixed model and a 95% confidence interval (CI). The test for heterogeneity was measured with the I(2) Altman DG test. RESULTS: At 24 hours, among the 308 adults tested, nausea and vomiting were significantly reduced by 22% and 57%, respectively; no significant reduction in vomiting was noted for the 149 children patients. At 48 hours, no significant modification was observed in adults. CONCLUSIONS: Peroperative intravenous dose of ondansetron 4 mg in neurosurgery in adults is required to prevent PONV during the first postoperative 24 hours. However, further studies are needed to determine best time and dose infusion to prolong clinical efficacy.

Efficacy and plasma levels of ropivacaine for children: controlled regional analgesia following lower limb surgery.

BACKGROUND: Continuous regional analgesia (CRA) is considered a safe and efficacious technique for postoperative pain relief in children after lower limb surgery. We recently evaluated the feasibility of patient-controlled regional analgesia (PCRA) in a similar acute pain situation and we concluded that PCRA might be advantageous over CRA in terms of lower costs, risk of systemic toxicity while producing similarly adequate analgesia. We therefore prospectively compared both techniques in the paediatric population. METHODS: In total, 30 children undergoing lower limb orthopaedic surgery were randomized to receive PCRA or CRA with ropivacaine 0.2%. Visual analogue scale scores, rescue analgesia, overall satisfaction, motor blockade and plasma ropivacaine concentrations were recorded for 48 h. RESULTS: Adequate analgesia was achieved with both techniques. No significant difference was noted for rescue analgesia, overall satisfaction and motor blockade. In contrast, children in the PCRA group received significantly less local anaesthetics than those in the CRA group. In addition, total plasma concentrations of ropivacaine were significantly reduced in the PCRA group as compared with the CRA group during the 48 h postoperative period. CONCLUSIONS: Both techniques are efficacious and satisfactory. However, PCRA with ropivacaine 0.2% can provide adequate postoperative analgesia for paediatric orthopaedic procedures with smaller doses of ropivacaine than CRA.

alpha2-adrenoceptors inhibit the intracellular Ca2+ response to electrical stimulation in normal and injured sensory neurons, with increased inhibition of calcitonin gene-related peptide expressing neurons after injury.

Nerve injury resulting in chronic pain is associated with novel excitatory effects of norepinephrine on injured peripheral nerve terminals and their cell bodies, due to actions on alpha2-adrenoceptors. Paradoxically, alpha2-adrenoceptor agonists administered near peripheral terminals or their cell bodies results in analgesia, not pain. This study tested, using intracellular Ca2+ response to stimulation, the effects of alpha2-adrenoceptor agonists on injured sensory neurons and classified their neuronal phenotype. Dorsal root ganglion cells from normal and spinal nerve-ligated rats were dissociated and activated twice with electrical field stimulation, while measuring Fura-2 fluorescence. Cells were perfused between stimulations with vehicle or alpha2-adrenoceptor agonists alone or with antagonists. Cells were considered inhibited if the ratio of their peak Ca2+ response to the second stimulus divided by the first was less than the 2.5th percentile for vehicle controls. alpha2-, But not alpha1-adrenoceptor agonists inhibited the Ca2+ response in a concentration related fashion, and this inhibition was blocked by alpha2-adrenoceptor antagonists. Clonidine inhibited a similar percentage of cells in the normal and spinal nerve-ligated group. In both groups, the large majority of clonidine-inhibited cells stained for isolectin B4. Spinal nerve ligation resulted in a 4-10-fold increase in the percentage of clonidine inhibited cells which immunostained for calcitonin gene-related peptide. These data are consistent with the known inhibition of Ca2+ currents by alpha2-adrenoceptors and suggest that, at the level of intracellular Ca2+, the key determinant of neurotransmitter release, alpha2-adrenoceptors are inhibitory after nerve injury, not excitatory. There is a shift in phenotype of sensory neurons which are inhibited by clonidine after nerve injury, which may explain clonidine's increased potency in the treatment of neuropathic compared with acute pain.

Alveolar and serum oxidative stress in ventilator-associated pneumonia.

BACKGROUND: In several lung diseases, oxidative stress can be demonstrated. This has not been shown in patients with ventilator-associated pneumonia (VAP). METHODS: We studied plasma and bronchoalveolar lavage (BAL) samples for markers of oxidative stress, taken from patients with VAP. Seventy-eight patients likely to have VAP and 10 patients who were not suspected of having VAP were studied prospectively. A diagnosis of VAP was based on a positive quantitative mini-lavage culture of > or = 10(3) colony-forming units per ml. Blood and BAL samples were collected and analysed for thiobarbituric acid reactant substances (TBARS) and antioxidant activity. RESULTS: Plasma and alveolar TBARS increased significantly in patients who developed VAP compared with those who did not, by 43% and 259% respectively. Red cells and alveolar glutathione peroxidase concentrations (antioxidant activity) were lower in those with VAP compared with the non-VAP group, by 43% and 68% respectively. No significant differences were found for serum superoxide dismutase activity. Significant differences were found for alveolar glutathione peroxidase concentrations over time in the VAP group. No significant differences between survivors and non-survivors were found in the blood or BAL assays, in patients with VAP. CONCLUSIONS: VAP is associated with evidence of early oxidative stress in the alveolar fluid and blood.

Noise in the postanaesthesia care unit.

BACKGROUND: Although the postanaesthesia care unit (PACU) can be noisy, the effect of noise on patients recovering from anaesthesia is unknown. We studied the sources and intensity of noise in the PACU and assessed its effect on patients' comfort. METHODS: We measured noise in a five-bed PACU with a sound level meter. Noise levels were obtained using an A-weighted setting (dBA) and peak sound using a linear scale (dBL). Leq (average noise level at 5-s intervals), maximum Leq (LeqMax), minimum Leq (LeqMin) and noise peaks (Lpc) were calculated. During recording, an independent observer noted the origin of sounds from alarms and noise above 65 dB intensity (P65dB). Two hours after leaving the PACU, patients were asked about their experience and to rank their complaints on a visual analogue scale (VAS) using unstructured and structured questionnaires. RESULTS: We made 20,187 measurements over 1678 min. The mean Leq, LeqMax and LeqMin were 67.1 (SD 5.0), 75.7 (4.8) and 48.6 (4.1) dBA respectively. The mean Lpc was 126.2 (4.3) dBL. Five per cent of the noise was at a level above 65 dBA. Staff conversation caused 56% of sounds greater than 65 dB and other noise sources (alarm, telephone, nursing care) were each less than 10% of these sounds. Five patients reported disturbance from noise. There was no significant difference in Leq measured for patients who found the PACU noisy and those who did not [59.5 (3.1) and 59.4 (2.4) dBA respectively]. Stepwise multiple logistic regression indicated that only pain was associated with discomfort. CONCLUSIONS: Even though sound in the PACU exceeded the internationally recommended intensity (40 dBA), it did not cause discomfort. Conversation was the most common cause of excess noise.

Pharmacokinetic parameters of ciprofloxacin (500 mg/5 mL) oral suspension in critically ill patients with severe bacterial pneumonia: a comparison of two dosages.

The authors determined the pharmacokinetic parameters of a new immediate-release ciprofloxacin suspension in tube-fed intensive care patients with bacterial pneumonia, to compare two dosage regimens: 500 mg b.i.d and 750 mg b.i.d. in this prospective clinical trial. The 20 patients were critically ill and on mechanical ventilation and enteral feeding with bacterial pneumonia. They were randomized to receive two different ciprofloxacin dosages: 500 mg b.i.d (group 1) versus 750 mg b.i.d. (group 2). Blood samples were collected from these patients after reaching steady-state and the pharmacokinetic parameters were determined. The mean (range) serum steady-state concentration at 2 h after enteral administration was: C(max 500) = 2.6 (1.2-4.3) mg/L in group 1 and C(max 750) = 3.5 (1.5-5.9) mg/L in group 2. The mean (range) calculated 12-h area under the serum concentration was high in both groups: AUC(0-12 (500)) = 24.7 (12.9-36.2) mg.h/L in group 1 and AUC(0-12 (750)) = 28.9 (18.3-47.5) mg.h/L in group 2. In conclusion, ciprofloxacin oral suspension was well absorbed via nasogastric route in intensive care patients with severe pneumonia, achieving reliable pharmacokinetic parameters for most of the pathogens and important cost reduction compared to intravenous delivery. However, with less susceptible pathogens such as Staphylococcus aureus or Pseudomonas aeruginosa, higher dosages than 750 mg b.i.d. should be given.

Penetration of piperacillin/tazobactam (4 g/500 mg) into synovial tissue.

The degree of penetration of an antibiotic into the infected site is an important criterion for therapeutic success. This is particularly true for bone and joint infections. The association of piperacillin and tazobactam has been widely used in the treatment of serious infections including bone infections, but no study has been devoted to the subject of its diffusion into synovial tissue. Our objective was to quantify piperacillin/tazobactam synovial tissue penetration and to estimate the efficacy of the association against the microorganisms usually encountered in joint infections. In an open-label study, 6 subjects with similar age, weight, height and creatinine clearance, who were undergoing elective total hip replacement, received a single, parenteral, 4 g/500 mg dose of piperacillin/tazobactam. Plasma and synovial tissue samples were collected and analyzed by a validated HPLC method. The mean concentrations of piperacillin and tazobactam 1.5 h after the initiation of infusion were 69.9 +/- 4.9 microg/mL and 7.7 +/- 0.3 microg/mL, respectively, in plasma and 37.1 +/- 2.1 microg/g and 2.8 +/- 0.4 microg/g, respectively, in synovial tissue. The synovial tissue/plasma ratios were 0.5 +/- 0.0 for piperacillin and 0.4 +/- 0.0 for tazobactam. The piperacillin/tazobactam ratios were 9.1:1 in plasma and 13.5:1 in synovial tissue. The concentrations achieved in synovial tissue are above the MICs of most of the susceptible pathogens usually involved in joint infections, which suggests that the piperacillin/tazobactam combination should be effective in the treatment of most joint infections caused by susceptible microorganisms.

Influence of sepsis on sevoflurane minimum alveolar concentration in a porcine model.

Sevoflurane is widely used in anaesthetic protocols for patients undergoing surgical procedures. However, there are no reports on the influence of sepsis on minimum alveolar concentration of sevoflurane (MAC(SEV)) in animals or in humans. The aim of this study was to test the hypothesis that sepsis could alter the MAC(SEV) in a normotensive septic pig model. Twenty young, healthy pigs were used. After they had received 10 mg kg(-1) of ketamine i.m. for premedication, anaesthesia was established with propofol 3 mg kg(-1) and the trachea was intubated. Sevoflurane was used as the sole anaesthetic agent. Baseline haemodynamic recording included electrocardiography, carotid artery blood pressure and a pulmonary thermodilution catheter. Baseline MAC(SEV) in each pig was evaluated by pinching with a haemostat applied for 1 min to a rear dewclaw. MAC(SEV) was determined using incremental changes in sevoflurane concentration until purposeful movement appeared. Pigs were assigned randomly to two groups: the saline group (n = 10) received a 1-h i.v. infusion of sterile saline solution while the sepsis group (n = 10) received a 1-h i.v. infusion of live Pseudomonas aeruginosa. Epinephrine and hydroxyethylstarch were used to maintain normotensive and normovolemic haemodynamic status. In both groups, MAC(SEV) was evaluated 5 h after infusion. Significant increases in mean artery pulmonary pressure, filling, epinephrine and vascular pulmonary resistances occurred in the sepsis group. MAC(SEV) for the saline group was 2.4% [95% confidence interval (CI) 2.1-2.55%] and the MAC(SEV) for the sepsis group was 1.35% (95% CI 1.2-1.45%, P<0.05). These data indicate that MAC(SEV) is significantly decreased in this normotensive septic pig model.

Oxidative stress status during exposure to propofol, sevoflurane and desflurane.

UNLABELLED: We evaluated the circulating and lung oxidative status during general anesthesia established with propofol, sevoflurane, or desflurane in mechanically ventilated swine. Blood samples and bronchoalveolar lavage fluid (BAL) specimens were respectively performed via an internal jugular vein catheter and a nonbronchoscopic BAL for baseline oxidative activity measurements: malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX). A 4-h general anesthesia was then performed in the three groups of 10 swine: the Propofol group received 8 mg x kg(-1) x h(-1) of IV propofol as the sole anesthetic; the Desflurane group received 1.0 minimum alveolar concentration of desflurane; and the Sevoflurane group received 1.0 minimum alveolar concentration of sevoflurane. We observed significantly larger levels of MDA in plasma and BAL during desflurane exposure than with the other anesthetics. We also observed smaller concentrations of circulating GPX and alveolar GPX. We found a significant decrease for MDA measurements in the plasma and the pulmonary lavage during propofol anesthesia. We also found larger values of GPX measurements in the serum and the pulmonary lavage. No significant changes were observed when animals were exposed to sevoflurane. No significant changes were found for circulating concentrations of SOD during exposure to all anesthetics. In this mechanically ventilated swine model, desflurane seemed to induce a local and systemic oxidative stress, whereas propofol and sevoflurane were more likely to have antioxidant properties. IMPLICATIONS: Superoxide is an unavoidable byproduct of oxygen metabolism that occurs in various inflammatory reactions. Inhalation of volatile anesthetics under mechanical ventilation induces an inflammatory response. We evaluated the bronchoalveolar and systemic oxidative stress in swine during exposure to propofol and newer volatile anesthetics. Desflurane induces more lipid peroxidation than do the other anesthetics.

Influence of sepsis on minimum alveolar concentration of desflurane in a porcine model.

The effect of sepsis on the minimum alveolar concentration of desflurane (MAC(DES)) in humans and other animals has not been reported previously. The aim of this study was to test the hypothesis that sepsis might alter MAC(DES) in a normotensive septic porcine model. Twenty-four young healthy pigs were premedicated with ketamine 10 mg kg(-1 )i.m and then anaesthesia was established with propofol 3 mg kg(-1) and the trachea was intubated. Baseline MAC(DES) in each pig was evaluated by pinching with a haemostat applied for 1 min to a rear dewclaw. MAC(DES) was determined by changing desflurane concentrations stepwise until purposeful movement appeared. Pigs were randomly assigned to two groups of 12 animals: the saline group received a 1 h i.v. infusion of saline solution while the sepsis group received a 1 h i.v. infusion of live Pseudomonas aeruginosa. Epinephrine and hydroxyethylstarch were used to maintain normotensive and normovolaemic haemodynamic status. In both groups, MAC(DES) was evaluated 5 h after infusion. Significant increases in heart rate, cardiac output, mean pulmonary artery pressure and pulmonary vascular resistance occurred in the sepsis group. MAC(DES) was 9.2% (95% confidence interval (CI) 6.8-10.6%) for the saline group and 6.7% (95% CI: 4.7-10.4) for the sepsis group (P<0.05). These data indicate that MAC(DES) is significantly decreased in this normotensive hyperkinetic septic porcine model.

An evaluation of the Gram stain in protected bronchoalveolar lavage fluid for the early diagnosis of ventilator-associated pneumonia.

We investigated the usefulness and reliability of the Gram stain value versus quantitative cultures in the early diagnosis of ventilator-associated pneumonia (VAP) using the protected bronchoalveolar lavage (PBAL). One hundred four mechanically ventilated patients (age = 52 +/- 19; SAPS II = 38 +/- 15) with a strong suspicion of VAP were consecutively included. One hundred sixteen PBAL were performed and mini-bronchoalveolar lavage were analyzed using the Gram stain standard method and the conventional quantitative culture technique. VAP diagnosis was based on a positive quantitative culture of mini-bronchoalveolar lavage fluid (cutoff > or = 10(3) CFU/mL). A final diagnosis of VAP was established in 67 patients and there was no infection in 49 cases. Regarding detection of bacteria using the Gram stain, we found a sensitivity of 76.2%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 75.4%. There was a good agreement with the final diagnosis (kappa statistic 0.73; concordance 86.2%). The degree of qualitative agreement between Gram stain and quantitative cultures was analyzed in the VAP group: the correlation was complete in 39% (26 of 67 VAP), partial in 28% (19 of 67 VAP) and there was no correlation in 33% (22 of 67 VAP). We conclude that despite its overall "good agreement," the Gram stain is of limited use for the rapid diagnosis of VAP and unreliable for the early adaptation of empirical antimicrobial therapy when using the noninvasive PBAL procedure.

The analgesic effect of sufentanil combined with ropivacaine 0.2% for labor analgesia: a comparison of three sufentanil doses.

UNLABELLED: The combination of opioids with local anesthetics is commonly used for epidural labor analgesia. We examined whether increasing sufentanil in doses of 5, 10, and 15 microg prolonged the duration of labor analgesia produced by ropivacaine. One hundred healthy parturients in the first stage of labor who requested epidural analgesia were enrolled. Parturients were randomized to receive 12 mL ropivacaine 0.2% alone or with sufentanil 5 microg, sufentanil 10 microg, or sufentanil 15 microg. The duration of analgesia, pain score, degree of motor blockade (using a four-point Bromage scale), heart rate, blood pressure, respiratory rate, oxygen saturation, and incidence of nausea and pruritus were recorded. The mean duration of epidural analgesia was 96 +/- 32 min for patients without sufentanil, 134 +/- 27 min for Group 5 (p < 0.01 versus control), 135 +/- 33 min for Group 10 (p < 0.01 versus control), 130 +/- 33 min for Group 15 (p < 0.01 versus control) without differences among sufentanil groups. Between 30 and 90 min, the sufentanil groups (5 microg, 10 microg, and 15 microg) had lower pain scores than the control group (p < 0.01 versus control) but there were no differences among the sufentanil groups. No patient in any group had a Bromage score more than 1. No significant difference was found for opioid-related side effects. We conclude that 5-10 or 15 microg sufentanil induced a similar prolongation of analgesia when combined with ropivacaine 0.2% for initiation of labor analgesia. IMPLICATIONS: We studied the effect of adding one of three possible sufentanil doses to epidural ropivacaine 0.2% for labor analgesia. Adding sufentanil increased the duration of analgesia but there was no advantage in adding more than 5 microg of sufentanil.