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Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Cranial sonography is a widely used point-of-care modality in infants. The authors evaluated that the respiratory variation of the internal carotid artery blood flow peak velocity as measured using transfontanelle ultrasound can predict fluid responsiveness in infants. Methods This prospective observational study included 30 infants undergoing cardiac surgery. Following closure of the sternum, before and after the administration of 10ml · kg–1 crystalloid, the respiratory variation of the aorta blood flow peak velocity, pulse pressure variation, and central venous pressure were obtained. The respiratory variation of the internal carotid artery blood flow peak velocity was measured using transfontanelle ultrasound. Response to fluid administration was defined as an increase in stroke volume index, as measured with transesophageal echocardiography, greater than 15% of baseline. Results Seventeen subjects (57%) were responders to volume expansion. Before fluid loading, the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity (means ± SD) of the responders were 12.6 ± 3.3% and 16.0 ± 3.8%, and those of the nonresponders were 8.2 ± 3.2% and 10.9 ± 3.5%, respectively. Receiver operating characteristic curve analysis showed that the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity could predict fluid responsiveness; the area under the curve was 0.828 (P < 0.0001; 95% CI, 0.647 to 0.940) and 0.86 (P = 0.0001; 95% CI, 0.684 to 0.959), respectively. The cutoff values of the respiratory variation of the internal carotid artery and the aorta blood flow peak velocity were 7.8% (sensitivity, 94%; specificity, 69%) and 13% (sensitivity, 77%; specificity, 92%), respectively. Conclusions The respiratory variation of the internal carotid artery blood flow peak velocity as measured using transfontanelle ultrasound predicted an increase in stroke volume in response to fluid. Further research is required to establish any wider generalizability of the results.

Background Pediatric cardiac patients are at risk for perioperative respiratory insufficiency. The objective of this study was to assess the utility of perioperative lung ultrasound examination in pediatric cardiac surgery. Methods In this randomized, controlled trial, children (5 yr old or younger) undergoing cardiac surgery were allocated into a control (n = 61) or intervention (n = 61) group. The control group received only lung ultrasound examinations at the end of surgery and 6 to 12 h after surgery. The intervention group received lung ultrasound examinations and an ultrasound-guided recruitment maneuver depending on ultrasound findings after inducing anesthesia, at the end of surgery, and 6 to 12 h after surgery. Primary outcomes were incidences of intra- and postoperative desaturation, and postoperative pulmonary complications. Multiple comparisons were corrected (P ≤ 0.017) in the primary outcome analysis. Results Of the 120 children included in the analysis, postoperative desaturation (64% vs. 27%; P < 0.001; odds ratio [OR], 0.210; 95% CI, 0.097 to 0.456) occurred more in the control group. The incidences of intraoperative desaturation (36% vs. 19%; P = 0.033; OR, 0.406; 95% CI, 0.176 to 0.939) and postoperative pulmonary complications (12% vs. 3%; P = 0.093; OR, 0.271; 95% CI, 0.054 to 1.361) were similar between the groups. Lung ultrasound scores were better in the intervention group than in the control group. Duration of mechanical ventilation was longer in the control group than in the intervention group (38 ± 43 vs. 26 ± 25 h; 95% CI of mean difference, 0 to 25; P = 0.048). Conclusions Perioperative lung ultrasound examination followed by ultrasound-guided recruitment maneuver helped decrease postoperative desaturation events and shorten the duration of mechanical ventilation in pediatric cardiac patients.

Background We evaluated the posterior tibial artery as an alternative arterial cannulation site to the radial artery in small children. Methods A two-stage study was conducted. First, we evaluated the anatomical characteristics of the posterior tibial artery compared with the radial and dorsalis pedis arteries. Next, a parallel-arm single-blind randomized controlled study compared the initial success rate of ultrasound-guided arterial cannulation among three arteries as a primary outcome. Results Sixty patients were analyzed in the observational study. The diameter of the posterior tibial artery (1.5 ± 0.2 mm) was similar to that of the radial artery (1.5 ± 0.2 mm) and larger than that of the dorsalis pedis artery (1.2 ± 0.2 mm; P < 0.001). The posterior tibial artery has a larger cross-sectional area (2.8 ± 1.1 mm2) compared with the radial (2.3 ± 0.8 mm2; P = 0.013) and dorsalis pedis arteries (1.9 ± 0.6 mm2; P = 0.001). In total, 234 patients were analyzed in the randomized study. The first-attempt success rate of the posterior tibial artery (75%) was similar to that of the radial (83%; P = 0.129; odds ratio, 1.53; 95% CI, 0.69 to 3.37) and higher than that of the dorsalis pedis artery (45%; P < 0.001; odds ratio, 3.95; 95% CI, 1.99 to 7.87). Median cannulation time of the posterior tibial artery (21 s; interquartile range, 14 to 30) was similar to that of the radial artery (27 s; interquartile range, 17 to 37) and shorter than that of the dorsalis pedis artery (34 s; interquartile range, 21 to 50). Conclusions The posterior tibial artery is a reasonable alternative to the radial artery for ultrasound-guided arterial cannulation in small children.

Background Intrathecal injection of local anesthetic agents is associated frequently with hypotension. Conversely, intrathecal administration of neostigmine increases blood pressure by enhancing the accumulation of acetylcholine in the spinal cord. The current study examined directly the interaction of intrathecal injection of bupivacaine and neostigmine on splanchnic sympathetic efferent nerve activity. Methods Experiments were performed in rats with intrathecal catheters implanted for the long-term. Rats were anesthetized with ketamine (40 mg/kg, intramuscularly) and alpha-chloralose (60 mg/kg, intraperitoneally). The skin incision sites were infiltrated with 1% lidocaine. Sympathetic efferent activity was recorded from the left greater splanchnic nerve. Sympathetic nerve activity was measured continuously before and after intrathecal injection of saline, 430 nmol (140 microg) of bupivacaine, 25 nmol (7.6 microg) of neostigmine, and a combination of bupivacaine and neostigmine all in volumes of 5 microl. Each group consisted of six animals. Results Compared with baseline nerve activity, intrathecal injection of neostigmine increased splanchnic sympathetic nerve activity significantly by (mean +/- SEM) 112 +/- 29% after an onset latency of 6.8 +/- 0.9 min. In contrast, bupivacaine decreased splanchnic nerve activity significantly (-65 +/- 13%) after a latency of 3.3 +/- 0.5 min after intrathecal administration. Similar to the effect of saline, intrathecal coadministration of bupivacaine and neostigmine did not alter the splanchnic sympathetic nerve activity significantly. Conclusions The current study provides electrophysiologic evidence that intrathecal injection of neostigmine increases whereas bupivacaine decreases sympathetic nerve activity. Further, addition of neostigmine effectively counteracts the inhibitory effect of spinal bupivacaine on the sympathetic nerve activity.