Correlated sodium and potassium imbalances within the ischemic core in experimental stroke: a 23Na MRI and histochemical imaging study.

This study addresses the spatial relation between local Na(+) and K(+) imbalances in the ischemic core in a rat model of focal ischemic stroke. Quantitative [Na(+)] and [K(+)] brain maps were obtained by (23)Na MRI and histochemical K(+) staining, respectively, and calibrated by emission flame photometry of the micropunch brain samples. Stroke location was verified by diffusion MRI, by changes in tissue surface reflectivity and by immunohistochemistry with microtubule-associated protein 2 antibody. Na(+) and K(+) distribution within the ischemic core was inhomogeneous, with the maximum [Na(+)] increase and [K(+)] decrease typically observed in peripheral regions of the ischemic core. The pattern of the [K(+)] decrease matched the maximum rate of [Na(+)] increase ('slope'). Some residual mismatch between the sites of maximum Na(+) and K(+) imbalances was attributed to the different channels and pathways involved in transport of the two ions. A linear regression of the [Na(+)]br vs. [K(+)]br in the samples of ischemic brain indicates that for each K(+) equivalent leaving ischemic tissue, 0.8±0.1 Eq, on average, of Na(+) enter the tissue. Better understanding of the mechanistic link between the Na(+) influx and K(+) egress would validate the (23)Na MRI slope as a candidate biomarker and a complementary tool for assessing ischemic damage and treatment planning.

Pediatric thoracic paravertebral block: roentgenologic evidence for extensive dermatomal coverage.

A case of a 10 year old boy who underwent a T10 continuous thoracic paravertebral block (TPVB) using a standard technique for postoperative pain management is reported. In the postoperative recovery area, 10 mL of Omnipaque contrast dye was injected through the catheter and an anteroposterior chest radiograph was performed. The radiograph showed longitudinal spread of contrast parallel to the spine from the T(4)-T(5) intervertebral disc to the T(10)-T(11) intervertebral disc with clear lateral extension of contrast along the fifth through the tenth intercostal nerves.

A feasibility study using the VivaSight Single Lumen™ to intubate the trachea through the Fastrach laryngeal mask airway: a preliminary report of 50 cases.

BACKGROUND: The VivaSight Single Lumen™ (SL) is new endotracheal tube with a video camera and a light source in the tip allowing continuous visual observation of the airway. In this study, we checked the feasibility of endotracheal intubation with a VivaSight-SL through the Fastrach Laryngeal Mask Airway(®) (FT-LMA). METHODS: We studied 50 patients with normal airways, scheduled for elective surgery during general anesthesia requiring endotracheal intubation. The FT-LMA was inserted and once adequate ventilation was achieved, the VivaSight-SL was passed through the FT-LMA into the trachea under visual control. The following criteria were used to score the laryngeal view: grade 1: full view of the arytenoids and glottis; grade 2: epiglottis, arytenoids or glottic opening are partly visible, the structure of cords is difficult to see; grade 3: dark areas indicating an open space; and grade 4: no part of the larynx can be identified. RESULTS: The FT-LMA was placed successfully in 49 patients at the first attempt. One patient was excluded from the study after 2 failed attempts to ventilate with the FT-LMA. All 49 patients were successfully intubated with the VivaSight-SL, (95% confidence interval [CI] 0.89-0.99), 47 patients at the first attempt (95% CI, 0.83-0.98) and 2 patients at the second attempt. (95% CI, 0.004-0.13). The time to achieve an effective airway with the FT-LMA was 15.4 ± 6 (mean ± SD) seconds. The time to achieve a laryngeal view with the VivaSight-SL was 28.8 ± 5 seconds. Correct position of the VivaSight-SL was confirmed with visualization of the carina. Time of successful intubation with VivaSight-SL from picking up the VivaSight-SL to observing a end-tidal CO(2) curve was 45 ± 7 seconds. After introducing the VivaSight-SL through the intubating channel of the FT-LMA, a grade 1 view was obtained in 18 patients, grade 2 in 18 patients, a grade 3 in 4 patients, and grade 4 in 9 patients. CONCLUSION: The high first-attempt intubation success rate using the VivaSight-SL to intubate the trachea through a FT-LMA makes this technique an attractive and promising concept.

Inhomogeneous sodium accumulation in the ischemic core in rat focal cerebral ischemia by 23Na MRI.

PURPOSE: To test the hypotheses that (i) the regional heterogeneity of brain sodium concentration ([Na(+)](br)) provides a parameter for ischemic progression not available from apparent diffusion coefficient (ADC) data, and (ii) [Na(+)](br) increases more in ischemic cortex than in the caudate putamen (CP) with its lesser collateral circulation after middle cerebral artery occlusion in the rat. MATERIALS AND METHODS: (23)Na twisted projection MRI was performed at 3 Tesla. [Na(+)](br) was independently determined by flame photometry. The ischemic core was localized by ADC, by microtubule-associated protein-2 immunohistochemistry, and by changes in surface reflectivity. RESULTS: Within the ischemic core, the ADC ratio relative to the contralateral tissue was homogeneous (0.63 +/- 0.07), whereas the rate of [Na(+)](br) increase (slope) was heterogeneous (P < 0.005): 22 +/- 4%/h in the sites of maximum slope versus 14 +/- 1%/h elsewhere (here 100% is [Na(+)](br) in the contralateral brain). Maximum slopes in the cortex were higher than in CP (P < 0.05). In the ischemic regions, there was no slope/ADC correlation between animals and within the same brain (P > 0.1). Maximum slope was located at the periphery of ischemic core in 8/10 animals. CONCLUSION: Unlike ADC, (23)Na MRI detected within-core ischemic lesion heterogeneity.

Flexible upper videoendoscopy through a modified endoscopy mask in infants and young children.

UNLABELLED: Esophagogastroduodenoscopy (EGD) is considered an essential diagnostic and therapeutic procedure in the pediatric population. Although generally safe, EGD has the potential for airway complications. We routinely use general anesthesia to carry out EGD in patients younger than 10 years. In the past, these patients received oxygen either through a nasal cannula or were intubated; both modalities have drawbacks and may be associated with complications. Here we report our experience using a modified endoscopy mask, devised primarily for bronchoscopy, for upper endoscopy in children under general anesthesia. RESULTS: Two hundred forty children (122 boys and 118 girls) participated in the study. Age range was 7 to 135 months (mean 60.7 +/- 34.4 months). All patients maintained a stable hemodynamic status throughout the procedure. Ventilation was satisfactory in 230 patients. It was difficult in 9 patients, and external airway maneuvers had to be applied. Ventilation was impossible in only 1 patient (10 months old), and endotracheal intubation was performed. There were no procedure-related complications. CONCLUSION: The modified endoscopy mask is efficient and safe and should be recommended for routine use for upper endoscopy under general anesthesia in children older than 6 months.

Sodium mapping in focal cerebral ischemia in the rat by quantitative (23)Na MRI.

PURPOSE: To validate (23)Na twisted projection magnetic resonance imaging (MRI) as a quantitative technique to assess local brain sodium concentration ([Na(+)](br)) during rat focal ischemia every 5.3 minutes. MATERIALS AND METHODS: The MRI protocol included an ultrashort echo-time (0.4 msec), a correction of radiofrequency (RF) inhomogeneities by B(1) mapping, and the use of 0-154 mM NaCl calibration standards. To compare MRI [Na(+)](br) values with those obtained by emission flame photometry in precision-punched brain samples of about 0.5 mm(3) size, MR images were aligned with a histological three-dimensional reconstruction of the punched brain and regions of interest (ROIs) were placed precisely over the punch voids. RESULTS: The Bland-Altman analysis of [Na(+)](br) in normal and ischemic cortex and caudate putamen of seven rats quantitated by (23)Na MRI and flame photometry yielded a mean bias and limits of agreement (at +/-1.96 SD) of 2% and 43% of average, respectively. A linear increase in [Na(+)](br) was observed between 1 and 6 hours after middle cerebral artery occlusion. CONCLUSION: (23)Na MRI provides accurate and reliable results within the whole range of [Na(+)](br) in ischemia with a temporal resolution of 5.3 minutes and precisely targeted submicroliter ROIs in selected brain structures.

Comparison of the CobraPLA (Cobra Perilaryngeal Airway) and the Laryngeal Mask Airway Unique in children under pressure controlled ventilation.

BACKGROUND: The Laryngeal Mask Airway-Unique (LMAU) and CobraPLA (Cobra Perilaryngeal Airway) are supraglottic airway devices. There are no published studies comparing these devices in children breathing with pressure controlled ventilation (PCV). METHODS: Eighty pediatric patients, scheduled for elective general surgery of short duration, were randomly assigned to have either a CobraPLA or a LMAU used for airway management using PCV. We compared the devices with respect to (i) ability to form an effective cuff seal, (ii) oxygenation, (iii) endtidal carbon dioxide level, (iv) time to achieve an effective airway, (v) airway interventions required for insertion, (vi) fiberoptic score, (vii) respiratory variables and (vii) adverse events. RESULTS: Cuff seal pressure was significantly higher for CobraPLA (27.08 +/- 4.15 cmH(2)O) than for LMAU (20.91 +/- 2.47 cmH(2)O). Oxygenation was similar in both groups while the mean endtidal CO(2) in the CobraPLA group was significantly higher than in the LMAU group (36.47 +/- 1.93 mmHg vs 34.71 +/- 3.05 mmHg, P = 0.021). Time and ease of insertion were similar, with CobraPLA requiring more frequent jaw lift and LMAU requiring more frequent adjustment of the head and neck to achieve a proper position. Fiberoptic scores were excellent with both devices. Respiratory variables were similar with the exception that the plateau pressure and mean peak pressures were significantly lower with CobraPLA. There was a low rate of blood mucosal staining of the devices. No patient in either group reported a sore throat. CONCLUSIONS: Both devices appear to be safe and effective in establishing an adequate airway in healthy children undergoing surgery of short duration with PCV.

Combined spinal-epidural anesthesia in major abdominal surgery in high-risk neonates and infants.

BACKGROUND: Combined spinal-epidural anesthesia (CSE-A) is reportedly safe and effective for the pediatric population in infraumbilical surgery. Our main purpose was to describe our experience of this technique in neonates and infants undergoing elective major upper abdominal surgery. METHODS: Spinal anesthesia was performed in 28 neonates and infants with isobaric bupivacaine 0.5%, 1 mg.kg(-1) followed by placement of a caudal epidural catheter to thoracic spinal segments. The catheter tip position was confirmed radiographically. Respiratory and hemodynamic data were collected before and after the CSE-A and throughout the operation, as a measure of anesthetic effectiveness. Complications related to the anesthesia technique were collected as a measure of the anesthetic technique safety. RESULTS: Satisfactory surgical anesthesia was achieved in 24 neonates and infants, four patients were converted to general anesthesia. Respiratory and hemodynamic variables did not change significantly during surgery, compared with baseline values: oxygen saturation (P = 0.07), systolic and diastolic blood pressures (P = 0.143, P = 0.198 respectively), heart rate (P = 0.080) and respiratory rate (P = 0.127). However, twenty infants were fussy during the surgical procedures and were calmed with intravenous midazolam; our patients required oxygen supplementation and transient manual ventilation intraoperatively. CONCLUSIONS: Combined spinal-epidural anesthesia could be considered as an effective anesthetic technique for elective major upper abdominal surgery in awake or sedated neonates and infants, and could be used cautiously by a pediatric anesthesiologist as an alternate to general anesthesia in high-risk neonates and infants undergoing upper gastrointestinal surgery.

Delayed ventricular fibrillation following blunt chest trauma in a 4-year-old child.

A 4-year-old boy who was involved in a motor vehicle accident as a pedestrian and suffered blunt chest trauma was admitted to the emergency room. Unpredictable delayed ventricular fibrillation was diagnosed and treated successfully 2 h later. This case cannot be classified as commotio cordis as the ventricular fibrillation (VF) developed so long after the sustained chest injury. At the same time, other possible etiologies of VF such as cardiac pathology or electrolyte and metabolic disorders had been ruled out. Thus, an etiological link between the chest trauma and the subsequent VF could not be ruled out and is in fact plausible despite the late onset.

Stroke onset time using sodium MRI in rat focal cerebral ischemia.

BACKGROUND AND PURPOSE: Thrombolytic therapy with intravenous tPA must be administered within 3 hours after stroke onset. However, stroke onset time cannot be established in 20% to 45% of potential patients. We propose that the rate of increase of the brain concentration of sodium ([Na+]br) after stroke, monitored using sodium MRI in a rat model of cortical ischemia, is linear in each individual animal, can locate the ischemic region, and can be used to estimate onset time. METHODS: After induction of focal cortical ischemia in rats under isoflurane anesthesia, [Na+]br time course maps were acquired continuously on a 3 T whole body scanner from 2 to 7 hours after occlusion followed by T2-weighted proton images. Microtubule-associated protein-2 immunostained brain sections were used to verify the location of the infarct. RESULTS: The ischemic region identified with microtubule-associated protein-2 corresponded to the region of maximum [Na+]br increase (P<0.001; n=5), and all of the animals demonstrated high linearity. [Na+]br increased at a mean rate of 25+/-4.7%/h in ischemic tissue (P=0.013) but not in normal cortex (1.0+/-1.1%/h; P=0.42). The mean onset time error was 1+/-4 minutes (n=4). CONCLUSIONS: These results of sodium MRI show that the region of maximum [Na+]br increase corresponds to the ischemic region. Although [Na+]br increases at a different rate in each animal, the increase is linear, and, therefore, onset time can be estimated. These findings suggest that this method can be used as a ticking clock to estimate time elapsed after vascular occlusion.

A comparison between the PLA Cobra and the Laryngeal Mask Airway Unique during spontaneous ventilation: a randomized prospective study.

The Laryngeal Mask (LMA) Unique and the Cobra Perilaryngeal Airway (PLA) are single-use supraglottic devices. There are no published studies comparing these devices during spontaneous ventilation. We compared the LMA Unique and the Cobra PLA with respect to 1) ventilatory variables during spontaneous ventilation, 2) time to achieve an effective airway, 3) airway intervention requirements, 4) cuff seal pressures, 5) fiberoptic score, and 6) perioperative adverse events. Eighty adult ASA physical status I-II patients undergoing general anesthesia for minor routine surgery were randomly allocated to LMA Unique or PLA Cobra for airway management. No statistically significant differences were found between the devices with respect to inspiratory tidal volume, expiratory tidal volume, end-tidal CO2 concentration, respiratory rate, number and type of airway interventions required with placement, the fiberoptic score, and the incidence of perioperative adverse events. The oropharyngeal leak (seal) pressure was higher for the CobraPLA (27 +/- 7 versus 21 +/- 4 cm H2O; P < 0.001). The oxygen saturation was higher (98.1% +/- 1% versus 97.3% +/- 2%; P = 0.02) in the LMA group. Time of insertion was shorter for LMA (23.7 +/- 2 s versus 26.6 +/- 7 s; P = 0.02) and insertion difficulty was less for LMA (P = 0.03). As these differences were not judged to be clinically important, both devices appear to be effective in establishing an adequate airway in patients who are spontaneously breathing under general anesthesia.

The esophageal-tracheal combitube resistance and ventilatory pressures.

STUDY OBJECTIVE: To measure resistance of the Combitube, a supraglottic ventilatory device used in the management of the patients with difficult airways, and its influence on delivered ventilatory pressures. DESIGN: Prospective study. SETTING: University-affiliated hospital. PATIENTS: A total of 20 patients with ASA status I or II who were scheduled for elective knee arthroscopy. INTERVENTIONS: (Part 2 of the study) After induction of general anesthesia and insertion of the Combitube, mechanical ventilation was initiated. Airway pressures were measured using fluid-filled pressure lines at the Y-piece (P(Y-piece)) of the breathing system and in the oropharynx (P(oropharynx)) at a position 2 cm beyond the second proximal anterior hole of the Combitube. These pressures were simultaneously recorded and the pressure curves were compared. MEASUREMENTS: (Part 1 of the study) Resistance of the esophageal and the tracheal lumen of the 37-F Combitube and standard endotracheal tubes (with internal diameters of 6, 7, and 8 mm) was compared ex vivo with a Datex AS/3 monitor. Ventilation conditions were kept constant at a tidal volume of 0.5 L, frequency of 10 breaths per minute, and ramp flow waveform and peak flow of 1 L/s. MAIN RESULTS: Resistance of standard endotracheal tubes was inversely proportional to their diameters (16, 11, and 7 cm H(2)O/L per second for the tubes with internal diameters of 6, 7, and 8 mm, respectively). The resistance of the Combitube's tracheal lumen was 12 cm H(2)O/L per second. There was a significant difference in peak respiratory pressures between P(Y-piece) and P(oropharynx) (40 +/- 5 and 23 +/- 5 cm H(2)O, respectively). CONCLUSIONS: The Combitube has significant airflow resistance that should be considered when patients are mechanically ventilated because the delivered oropharyngeal pressure is significantly lower than the pressure measured at the anesthesia breathing system.

A randomized controlled trial comparing the ProSeal Laryngeal Mask Airway with the Laryngeal Tube Suction in mechanically ventilated patients.

BACKGROUND: The ProSeal Laryngeal Mask Airway (PLMA) (Laryngeal Mask Company, Henley-on-Thames, United Kingdom) is a new laryngeal mask with a modified cuff designed to improve its seal and a drain tube for gastric tube placement. Similarly, the Laryngeal Tube Suction (LTS) (VBM Medizintechnik Gmbh, Sulz a.N, Germany) is a new laryngeal tube that also has an additional channel for gastric tube placement. This study compared the placement and functions of these two devices. METHODS: One hundred fifty patients undergoing general anesthesia for elective surgery were randomly allocated to the PLMA (n = 75) or LTS (n = 75). Oxygenation and ventilation, ease of insertion, fiberoptic view, oropharyngeal leak pressure, ventilatory data, ease of gastric tube insertion, and postoperative airway morbidity were determined. RESULTS: After successful insertion of the devices in 96% of patients with the PLMA and in 94.4% with the LTS it was possible to maintain oxygenation, ventilation, and respiratory mechanics during the entire duration of surgery. Successful first and second attempt insertion rates were 57 patients (76%) and 15 patients (20%), respectively, for the PLMA and 60 patients (80%) and 11 patients (14.6%), respectively, for the LTS. Airway placement was unsuccessful with the PLMA in three patients and with the LTS in four patients. Time to achieve an effective airway was 36 +/- 24 s with the PLMA versus 34 +/- 25 s with the LTS. Gastric tube insertion was possible in 97.3% of patients with the PLMA and in 96% with the LTS. CONCLUSIONS: With respect to both physiologic and clinical function, the PLMA and LTS are similar and either device can be used to establish a safe and effective airway in mechanically ventilated anesthetized adult patients.

An evaluation of the Laryngeal Tube during general anesthesia using mechanical ventilation.

UNLABELLED: The Laryngeal Tube is a new supraglottic ventilatory device for airway management. It has been developed to secure a patent airway during either spontaneous or mechanical ventilation. In this study, we sought to determine the effectiveness of the Laryngeal Tube for primary airway management during routine surgery with mechanical ventilation. One-hundred-seventy-five subjects classified as ASA physical status I and II, scheduled for elective surgery, were included in the study. After the induction of general anesthesia and insertion of a Size 4 Laryngeal Tube, measurements of oxygen saturation, end-tidal CO(2) and isoflurane concentration, and breath-by-breath spirometry data were obtained every 5 min throughout surgery. The lungs were ventilated with volume-controlled mechanical ventilation. The number of attempts taken to insert the Laryngeal Tube and the insertion time were recorded. In 96.6% of patients, it was possible to maintain oxygenation, ventilation, and respiratory mechanics by using mechanical ventilation throughout the surgical procedure. The results of this study suggest that the Laryngeal Tube is an effective and safe airway device for airway management in mechanically ventilated patients during elective surgery. IMPLICATIONS: In 96.6% of patients intubated with the Laryngeal Tube, it was possible to maintain oxygenation, ventilation, and respiratory mechanics during mechanical ventilation.

Postdural puncture headache: an imaging-guided management protocol.

IMPLICATIONS: We propose an imaging-based algorithm for the management of headache caused by the inadvertent puncture of dura that occurs sporadically during epidural analgesia. Its implementation can identify those postdural puncture headache cases that cannot benefit from epidural blood patches, and their unnecessary application can consequently be avoided.

Effect of ilioinguinal nerve block on the catecholamine plasma levels in orchidopexy: comparison with caudal epidural block.

BACKGROUND: Both caudal epidural and ilioinguinal/iliohypogastric nerve blocks have been used to provide effective intra- and postoperative analgesia. Stress response hormone levels can be used as an objective method to assess the analgesic efficacy of the anaesthetic techniques used in infraumbilical surgery in children. In this study, we compared catecholamine blood levels in children undergoing these two different supplementary analgesic/anaesthetic techniques. METHODS: Thirty male paediatric patients undergoing orchidopexy, ASA I, received inhalation general anaesthesia, and were randomly allocated to one of two groups: a caudal group (n = 15) and an ilioinguinal/iliohypogastric nerve block group (n = 15). Plasma epinephrine and norepinephrine concentrations were measured at the induction time, at the end of surgery, and in the postanaesthesia care unit. Postoperative pain score was also assessed in the postanaesthesia care unit. RESULTS: In both groups, there was a substantial decrease in the catecholamine blood levels; however, there were significantly higher levels of epinephrine in the ilioinguinal group at the end of surgery (P = 0.008) and in the recovery room (P = 0.02) and a significant higher level of norpinephrine in the recovery room (P = 0.008). CONCLUSIONS: The result of this study revealed that caudal epidural block was more effective than ilioinguinal block in suppressing the stress response as reflected in epinephrine and norepinephrine blood levels in orchidopexy patients.