Compression stockings reduce the incidence of hypotension but not that of cerebral desaturation events in the beach-chair position: a randomized controlled trial / 대한마취과학회지

BACKGROUND: The beach-chair position (BCP) results in decreases in venous return, cardiac output, and cerebral perfusion pressure. In this randomized, prospective study, we investigated whether applying thigh-high compression stockings affected the maintenance of regional cerebral tissue oxygen saturation (rSO2) in the BCP. METHODS: Patients undergoing orthopedic surgery in the BCP under general anesthesia were included and assigned randomly to the control or the compression stocking group. Appropriately sized thigh-high compression stockings were applied to the patients in the stockings group. All patients were tilted, up to 45°, throughout the operation. Non-invasive blood pressure, invasive arterial blood pressure zeroed at the external auditory meatus, and rSO2 were recorded. RESULTS: Data were analyzed from 19 patients per group. In the BCP, the values of rSO2 and blood pressure decreased significantly compared with those at baseline, with no significant difference between the groups. The incidences of cerebral desaturation events (CDEs) were similar between the groups; however, that of hypotension was significantly lower in the compression stocking group. During 36 CDEs, the levels of rSO2 and blood pressure decreased significantly compared with those at baseline in both groups. No significant correlation was found between rSO2 and blood pressure. CONCLUSIONS: Thigh-high compression stockings reduced the incidence of hypotension but not that of CDEs. Our results suggest that other factors, beyond hypotension itself, contribute to CDEs and in other words, efforts just to reduce the incidence of hypotension may not mainly contribute to a reduction of CDEs occurrence in the BCP under general anesthesia.

A retrospective analysis of neurological complications after ultrasound guided interscalene block for arthroscopic shoulder surgery

BACKGROUND: Ultrasound-guided interscalene brachial plexus block (US-ISB) has been reported to be effective postoperative analgesia for arthroscopic shoulder surgery. Although considered rare, various neurological complications have been reported. We retrospectively evaluated 668 patients for post operation neurological symptoms including hemidiaphragmatic paresis and post-operative neurologic symptoms after US-ISB. METHODS: We performed a retrospective chart review of 668 patients undergoing shoulder surgery with single-shot US-ISB from January 2010 to May 2015. The general anesthesia prior to the US-guided ISB procedure was standardized by expert anesthesiologists. Neurological postoperative complications were evaluated at 48 hours, about 2 weeks, 1 month, 3 months, 6 months, and up to resolution after operation. RESULTS: Three patients (0.4%) developed hemidiaphragmatic paresis (HDP), which were likely US-ISB associated and improved within 1 day. Two patients developed sensory symptoms, also likely US-ISB associated; one was paresthesia at the tip of the thumb/index finger, which resolved within 2 weeks, and the other was hypoesthesia involving the posterior auricular nerve, which resolved within 6 months. Motor and sensory symptoms which were not likely associated with US-ISB were hypoesthesia and pain (n = 28, 4.6%) and motor weakness (n = 2, 0.3%). CONCLUSIONS: Incidence of HDP and neurological complications, respectively 0.4% and 0.3%, related to transient minor sensory symptoms occurred after US-ISB for arthroscopic shoulder surgery but the complications improved spontaneously. Therefore, we confirm that the US-ISB procedure with low volumes of local anesthetics is an acceptable technique with a low rate of HDP and neurological complications.

Retrospective Analysis of Difficult Intubation / 이화의대지

OBJECTIVES: We analyzed retrospectively incidence, management, and predictors of difficult intubation, which have been known through practical cases. METHODS: A total of 217 cases of difficult intubation (DI) between 2010 and 2014 were investigated. Risk factors such as age, body mass index, Mallampati score, thyromental distance, degree of mouth opening and range of neck motion, Cormack-Lehane grade, intubation and airway management techniques were investigated. The cases of each department were analyzed and the airway management techniques according to simplified risk scores (SRS) were also investigated. RESULTS: The average incidence of DI was 0.49%. Patients undergoing surgery in the departments of oro-maxillo-facial surgery (1.35%), ophthalmologic surgery (0.96%), urologic surgery (0.80%), and head and neck surgery of ear-nose-throat (0.62%) showed the higher incidence of DI. Difficult mask ventilation (10 of 217, 4.6%) was occurred with DI. Higher SRS were related to high rates of video laryngoscope use and fiberoptic guided intubation. There was a decrease in the use of McCoy blades after 2013, an increase in the use of video laryngoscope, and a consistent rate of fiberoptic intubation. CONCLUSION: It is not easy to check all the predictors of DI in a preanesthetic evaluation and the predictors are not accurate. The role of clinical preparation and practical management is important, and the most important thing is to establish a planned induction strategy. Multiple factors system, such as simplified risk factors should be used to evaluate patients to prepare for appropriate airway management techniques in case of DI.

Dyspnea due to Residual Neuromuscular Blockade in Elderly Patient with Unrecognized Pre-existing Unilateral Vocal Cord Paralysis / 이화의대지

Muscle relaxation using neuromuscular blocking agent is an essential process for endotracheal intubation and surgery, and requires adequate recovery of muscle function after surgery. Residual neuromuscular blockade is defined as an insufficient neuromuscular recovery that can be prevented by confirming train-of-four ratio >0.9 using objective neuromuscular monitoring. Sugammadex, a novel selective relaxant-binding agent, produces rapid and effective reversal of rocuronium-induced neuromuscular blockade. We report a case of the residual neuromuscular blockade accompanying dyspnea and stridor after general anesthesia in an unrecognized pre-existing symptomless unilateral vocal cord paralysis patient, who had experienced the disappearance of dyspnea and stridor after administration of sugammadex.

Hypoesthesia of the Cutaneous Branch of Cervical Plexus after Shoulder Arthroscopy under General Anesthesia with Ultrasound Guided-Interscalene Block / 이화의대지

We present an uncommon case of hypoesthesia in the posterior and upper third of the superior area on the left ear auricle, after arthroscopic surgery of the shoulder in the lateral position under general anesthesia with ultrasound guided-interscalene brachial plexus block. A 65-year-old man underwent arthroscopic rotator cuff repair of the left shoulder in the right lateral decubitus position. Two days after operation, he complained of numbness around the left auricle; his symptoms persisted until 6 weeks after surgery. Audiometry and sensory examinations were normal. He recovered naturally by 6 months postoperatively. Postoperative neurological deficits that may not be block-related can be attributed to a combination of factors, such as patient-, anesthesia-, and surgery-related factors, including direct trauma, positioning, and retraction. Anesthesiologists should be aware that the injury may not be block-related and consider other possible causes.