Repetitive cerebral blood flow measurements using laser speckle imaging in a transient cerebral ischemic mouse model.

Using laser speckle imaging (LSI), which can visualize quadratic distribution of blood flow, we measured blood flow changes in transient cerebral ischemic mice, and compared these results with data obtained using laser Doppler flowmetry (LDF). In addition, we examined the relationship between ischemic damage and blood flow change. ICR mice (n = 22) were subjected to transient middle cerebral artery occlusion using a 6-0 monofilament under general anesthesia. LSI was performed before -ischemia, during ischemia, and 30 min, 3 h, 24 h, 7 days, and 28 days after ischemia. LDF was monitored continuously from pre-ischemia to 10 min after ischemia commenced. The level of cerebral blood flow (CBF) measured by LSI was less than that using LDF. LSI was able to measure CBF quantitatively and repeatedly. Blood flow -measurements using LSI revealed that recovery of cerebral cortical blood flow after ischemia in mice without cortical infarction was earlier than that seen in mice with cortical infarction. This study indicates that LSI is a -useful technique for analyzing the relationship between -tissue damage and cerebral blood flow change following cerebral ischemia.

[Use of Airwayscope with pediatric intlock in a patient with first and second branchial arch syndrome].

First and second branchial arch syndrome is a congenital anomaly of craniofacial dysplasia involving organs derived from the second branchial arch. The main characteristics are microtia and mandibular hypoplasia. A 6-year-old boy was scheduled for adenoidectomy and bilateral myringotomy and tube placement. Slow induction was performed with oxygen, nitrous oxide, and sevoflurane. No difficulties were encountered during mask ventilation, and rocuronium was administered intravenously. His epiglottis was not visible during laryngoscopy. Therefore, we used the Airwayscope (AWS). His glottis was visible after application of cricold pressure from the left side. However, we could not closely conform his epiglottis to the mark on the AWS. Therefore, we passed a fiberoptic bronchoscope through a tracheal tube and placed it in the AWS. We attempted to intubate the trachea, but could not guide the bronchoscope to his glottis. We then attempted to pull the tracheal tube to improve the mobility of the bronchoscope. Control of the bronchoscope consequently became easy We successfully guided it to his glottis and performed tracheal intubation. His condition was stable during the procedure. In conclusion, we safely performed tracheal intubation in a patient with first and second branchial arch syndrome using the AWS and a fiberoptic bronchoscope.

Displacement of the common carotid artery after laryngeal mask airway placement in infants and children.

BACKGROUND: In adults, placement of the laryngeal mask airway causes increased overlapping of the internal jugular vein (IJV) and common carotid artery (CCA). However, few studies in children have been reported. The aim of this study was to describe the degree of overlap of the IJV and the CCA before and after laryngeal mask airway placement in infants and children. METHOD: There were 160 children scheduled to undergo Protex(®) SoftSeal(®) and Ambu(®) placement. Patients were initially positioned in the 15° Trendelenburg position with their heads rotated 30° to the left. The ultrasound probe was placed perpendicular to the skin, and the images of the right IJV and CCA were collected at the level of the cricoid cartilage. Following laryngeal mask airway placement, images were collected in the same manner. RESULTS: No statistically significant changes were observed in the overlap index before and after laryngeal mask airway placement. By inflating the laryngeal mask airway cuff, migration of the vessel forward was 24.38% and outward migration was 13.99%. CONCLUSION: There was no remarkable change in the overlap index before and after laryngeal mask airway placement in children.

Rotation of the head might not be recommended for internal jugular puncture in infants and children.

BACKGROUND: Traditionally, we have been puncturing the internal jugular vein (IJV) with the head rotated. However, in adults it has been suggested that rotation of the head increases the magnitude of an overlapping of the IJV to the carotid artery (CA). Therefore, in infants and children, we have examined anatomic relationship between the IJV and the CA under the head in midline and head in rotated position. METHOD: Eleven infants and 51 children were included. Under general anesthesia, the patient was positioned in the Trendelenburg position with a shoulder roll to allow extension of the neck. At first, the head was placed in the midline position. The ultrasound probe was placed perpendicular to the skin, and images of the right IJV and CA were collected at the level of the cricoid cartilage. Then, the head was rotated to the left at 45 degrees. The images were collected in the same way. The position of the right IJV relative to the CA was defined as anterior (A), anterolateral (AL), or lateral (L). RESULTS: Rotation of the head increased the magnitude of an overlapping because of more changes from L --> AL, L --> A, or AL --> A (P < 0.05, Wilcoxon t-test). CONCLUSION: We conclude that the rotation of the head increases the magnitude of an overlapping of the IJV to the CA in infants and children.

Central venous catheterization in infants and children--small caliber audio-Doppler probe versus ultrasound scanner.

BACKGROUND: Ultrasound guidance for cannulation of the internal jugular vein has been shown to increase the success rate and reduce the incidence of complications in infants and children. We compared the use of a small caliber audio-Doppler probe with an ultrasound scanner for cannulation of a central venous (CV) line via the right internal jugular vein in infants and children. METHODS: Fifty-two infants and 29 children scheduled for open-heart surgery were enrolled. Cannulation was guided using a small caliber audio-Doppler probe (the AU group, n = 42), or an ultrasound scanner image (the US group, n = 39). Ultimate success rate, success rate at the first attempt, success rate within 5 min, and complications were compared for the two groups. RESULTS: In children (>12 months), both methods were equally efficient. But in infants (<12 months), success rate at the first attempt using audio-Doppler was worse than the rate using an ultrasound scanner and there were more complications when audio-Doppler was used. CONCLUSIONS: We conclude that application of both the audio-Doppler and the ultrasound scanner is useful in children over 1 year of age for access to the internal jugular vein. However, in infants and neonates, the ultrasound scanner would be more useful than the audio-Doppler.

The optimal insertion length of central venous catheter via the femoral route for open-heart surgery in infants and children.

BACKGROUND: The recommended insertion length of central venous (CV) catheter via the internal jugular or subclavian vein has been determined in infants and children. However, the insertion length via the femoral vein has not been well-studied. This study determined the optimal insertion length of CV catheter via the femoral vein. METHODS: Infants and children, who had undergone cardiac catheterization via the right femoral vein, were the subjects of the study. After routine cardiac catheterization, the distance from the femoral puncture site to the third lumbar vertebral body (L3) level, was measured and recorded. The femoral-L3 length was termed as the optimal insertion length. RESULTS: This length was measured in 78 infants and children (age: 1-101 months, weight: 3.1-33.8 kg). The body weight of the patient and the length correlated well: the optimal insertion length (cm) = 0.45 x body weight (kg) + 8.13, coefficient of determination (R2) = 0.84. CONCLUSIONS: It has been recommended to place the tip of the catheter below the level of renal veins to avoid blocking free flow of those veins. Therefore, we chose the mid-point, L3 level as the optimal tip position of the femoral venous catheter. The length derived from the above formula could be used as a guideline for CV catheter insertion via the femoral vein in infants and children.

Cephalad origin of the superior vena cava and the level of the central venous catheter tip on chest radiographs.

BACKGROUND: There are suggested radiographic landmarks for the lower margin of the superior vena cava (SVC), but none for the cephalad origin of the SVC in children. Therefore, we determined the cephalad origin of the SVC in relation to the level of thoracic vertebrae in children. METHODS: Sixty-five patients (2-96 months) scheduled for routine diagnostic cardiac catheterization were the subjects of the study. Vena cavogram was obtained. The crossing point between the SVC and the innominate vein was considered as the cephalad origin of the SVC, then this point was related to the level of the thoracic vertebra as a radiographic landmark. RESULTS: In approximately 90% of the patients studied the proximal origin of the SVC was situated above the level of Th4/5 interspace. CONCLUSION: We would like to suggest that the position of the tip of central venous line, when inserted via the right internal jugular vein, should optimally be at the level of Th4/5 interspace on the postoperative chest radiograph.

Audio-Doppler guidance using a small-caliber Doppler probe for internal jugular venous puncture for central venous catheterization in infants and children.

BACKGROUND: We evaluated an audio-Doppler with a small-caliber probe as a guide for central venous cannulation (CVC) via the internal jugular vein (IJV) in infants and children. METHODS: The right IJV was located with a small-caliber (2.0 mm in diameter) audio-Doppler probe using 10 MHz ultrasound. The probe was placed on the neck about the level of sixth cervical vertebra and was moved until the crisp pulsatile sound of the carotid artery was identified. Then the probe was moved laterally to identify the low-pitched venous hum of the right IJV. After marking the puncture site on the skin, a sterile cannulation procedure was performed. Ultimate success rate, cannulation time < 10 min, successful cannulation within three punctures, and complications were recorded. RESULTS: Ultimate success rate was 65.6% (42/64) in infants (< 12 m), and 94.7% (72/76) in children (12 m or older). Cannulation time < 10 min was 48.4% in infants, and 85.5% in children. Successful cannulation within three punctures was 45.3% in infants and 82.8% in children. Three carotid arterial punctures occurred. CONCLUSIONS: We were not able to demonstrate absolute superiority of the results utilizing this device over the reported results of traditional landmark techniques for CVC via the right IJV. However, this device may contribute to reducing complications and be of value in teaching residents where to insert a needle for an internal jugular puncture.

Differential lung ventilation in an infant using LMA and a long tracheal tube.

This is a case report of differential lung ventilation in an infant using a conventional laryngeal mask airway (LMATM) and a commercially available longer paediatric tracheal tube. This 2-month-old infant had her left-sided congenital diaphragmatic hernia repaired on the sixth day of her life, and had been mechanically ventilated. The right middle lobe became grossly emphysematous and herniated into the left side of the chest, and the right lower lobe became totally atelectatic. A right middle lobe lobectomy was planned. To avoid hyperinflating the right middle lobe, and to expand the right lower lobe without providing a high airway pressure on the left lung, the dependent lung (i.e. left lung) was ventilated with an LMA, and the right lower lobe was expanded with a long tracheal tube inserted through the LMA via the swivel connector. This combination of a conventional LMA and a commercially available longer paediatric tracheal tube could be another way of providing differential ventilation in infants.