Ultrasound in medicine & biology
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Ultrasound Med Biol · Jun 2015
Effect of cervical sympathetic block on optic nerve sheath diameter measured by ultrasonography.
Optic nerve sheath diameter (ONSD) measurement using ocular ultrasonography was introduced as a non-invasive technique to assess intracranial pressure. We investigated changes in ONSD after cervical sympathetic block (CSB). Ultrasound-guided CSB was performed with a lateral approach at the C6 level in 35 patients. ⋯ A comparison of ONSDs between the blocked and non-blocked sides revealed that these values did not differ significantly between sides at baseline and after CSB. On the basis of these preliminary data, CSB caused an increase in ONSD in patients without intracranial pathology or neurologic disorders. Further larger and controlled studies of the effect of CSB on intracranial pressure in humans are needed to confirm our findings.
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Ultrasound Med Biol · May 2015
Comparative StudyTranscranial ultrasound to detect elevated intracranial pressure: comparison of septum pellucidum undulations and optic nerve sheath diameter.
Two ultrasound tests that can be used to assess increased intracranial pressure (ICP) at the bedside are described. In outpatients receiving lumbar puncture and in intensive care patients with invasive ICP monitoring, we measured the optic nerve sheath diameter (ONSD) with transbulbar B-mode sonography and septum pellucidum undulation (SPU) induced by repeated passive head rotation with transtemporal M-mode sonography. We assessed the sensitivity and specificity of ONSD and SPU in the prediction of ICP >20 cm H2O. ⋯ The sensitivity of the SPU test was 75% and the specificity 100% (n = 32, p < 0.001). Although the SPU test may not feasible in some patients, it has high sensitivity and specificity comparable to those of ONSD measurement. The SPU test and ONSD may be useful alternatives to fundoscopy in clinical routine, preferably in combination.
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Ultrasound Med Biol · May 2015
Reliability of ultrasound evaluation of hyoid-larynx approximation with positional change.
We evaluated the reliability of ultrasound evaluation of hyoid-larynx approximation with positional change. Twenty healthy volunteers (10 men, 10 women) participated in this study. The distance between the hyoid bone and thyroid cartilage was measured by ultrasound in both the sitting and supine positions. ⋯ However, there was a negative correlation between the resting and approximation distance and body mass index. In conclusion, ultrasound evaluation in healthy volunteers revealed no difference in hyoid-laryngeal approximation on swallowing in either the supine or sitting position. This finding is likely to be of value in the investigation of dysphagia.
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Ultrasound Med Biol · May 2015
Comparative StudyComparison of three methods for the confirmation of laryngeal mask airway placement in female patients undergoing gynecologic surgery.
The laryngeal mask airway (LMA) is a supraglottic device that is commonly used to provide lung ventilation during general anesthesia. LMA placement needs to be confirmed to provide adequate lung ventilation. To investigate the feasibility of using ultrasound examination, compared with clinical tests and fiberoptic laryngoscopy, to confirm LMA placement, we performed a clinical study of 64 female patients classified as American Society of Anesthesiologists Physical Status I or II who were scheduled for gynecologic surgery with LMA insertion for airway management. ⋯ Of the 64 women, placement was confirmed as acceptable in 89.1% by clinical tests, in 59.4% by fiberoptic laryngoscope assessment and in 67.2% by ultrasound examination. With respect to patients with oropharyngeal leaks classified as high, there were no differences in confirmation of acceptable placement between clinical tests and ultrasound examinations (p = 0.092), but the number of patients determined to have acceptable placement by ultrasound examination was greater than that determined by fiberoptic laryngoscopy (p = 0.034). Thus, ultrasound examination is a superior technique for confirming the seal on the LMA.
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Ultrasound Med Biol · May 2015
Observational StudyUltrasonographic assessment of optic nerve sheath diameter during pediatric laparoscopy.
This study investigated the extent of the raised intracranial pressure resulting from carbon dioxide (CO2) pneumoperitoneum by ultrasonographically measuring optic nerve sheath diameter (ONSD) in children undergoing laparoscopic surgery. Twenty-five children aged less than 9 y (53.1 ± 23.3 mo, mean ± standard deviation) and scheduled for an elective laparoscopic surgery participated. ⋯ In all enrolled patients, any neurologic complications were not observed during the intra-operative or post-operative period. In children undergoing laparoscopic surgery, an increase in ONSD was ascertained during CO2 pneumoperitoneum, and thus the corresponding increase in intracranial pressure could be predicted.