Usefulness of an automatic cuff pressure controller (SmartCuff) in inhibiting gasleakage around the cuff after tracheal intubation: a randomized controlled study.

PURPOSE: Gas leakage around the cuff of a tracheal tube may frequently occur after tracheal intubation and inflation of the cuff. We assessed if the SmartCuff (Smiths Medical Japan, Tokyo, Japan), an automatic cuff pressure controller, would effectively prevent gas leakage. METHODS: Seventy adult patients were allocated randomly to one of two groups. After induction of general anesthesia and tracheal intubation, in one group (Syringe group), a syringe was used to inflate the cuff, until there was no audible gas leakage, at the airway pressure at 20 cmH2O. In the other group (SmartCuff group), the SmartCuff was used to maintain the cuff pressure to be 20 cmH2O. The mechanical ventilation (tidal volume of 8 ml.kg-1 and 12 breaths per min) was started. The incidence and percentage of gas leakage, and the proportion of adequate seal (defined as gas leakage of < 10%) between the groups were compared. RESULTS: The incidence of audible gas leakage was significantly higher in the Syringe group (10 of 35 patients (28%)) than in the SmartCuff group (none of 35 patients (0%)) (P = 0.00046, 95%CI for difference: 15-43%), and the proportion of adequate seal was significantly lower in the Syringe group (19 of 35 patients (54%)) than in the Smart cuff group (33 of 35 patients (94%)) (P = 0.0001, 95% CI for difference: 20-58%). CONCLUSION: Gas leakage may frequently occur after tracheal intubation, and the use of the SmartCuff can effectively maintain the sealing effect of the cuff.

Tracheal tube cuff pressure during anesthesia for robotic-assisted laparoscopic prostatectomy and the efficacy of an automatic cuff pressure controller (SmartCuff): observational studies of 1-sample paired data.

PURPOSE: The cuff pressure of a tracheal tube may increase during robot-assisted laparoscopic surgery for prostatectomy (RALP), which requires pneumoperitoneum in a steep head-down position, but there have been no studies which confirmed this. METHODS: In study 1, we studied how frequently the cuff pressure significantly increased during anesthesia for the RALP. In study 2, we studied if the SmartCuff (Smiths Medical Japan, Tokyo) automatic cuff pressure controller would minimize the changes in the intracuff pressure. With approval of the study by the research ethics committee (approved number: 20115), we measured the cuff pressures in anesthetized patients undergoing RALP and in those undergoing gynecological laparotomy (as a reference cohort), with and without the use of the SmartCuff. RESULTS: In 21 patients undergoing RALP, a clinically meaningful increase (5 cmH2O or greater) was observed in all the 21 patients (P = 0.00; 95% CI for difference: 86-100%), whereas in 23 patients undergoing gynecological laparotomy, a clinically meaningful decrease (5 cmH2O or greater) was observed in 21 of 23 patients (91%, P < 0.0001; 95% CI for difference: 72-99%). With the use of the SmartCuff, there was no significant increase in the incidence of a clinically meaningful change in the intracuff pressure in either cohort. CONCLUSION: The cuff pressure of a tracheal tube would frequently increase markedly in patients undergoing RALP, whereas it would frequently decrease markedly in patients undergoing gynecological laparotomy. The SmartCuff may inhibit the changes in the cuff pressure during anesthesia.

Efficacy of an aerosol suction device Free-100 M in removing aerosols produced by coughing to minimize COVID-19 infection.

PURPOSE: The healthcare workers are at the greatest risk of being exposed to viral infection during airway management of a patient with coronavirus disease 2019 (COVID-19). An air extractor which suctions air around the patient's face would reduce the spread of viral aerosols during coughing, but no study has confirmed this. We assessed whether or not an air extractor reduces the amount of aerosols spreading toward the operator's face, during coughing of simulated patients. METHODS: After obtained approval of the study by a research ethics committee and written informed consent from 20 volunteers (and additional 20 volunteers), we asked each volunteer to lie supine on a table in a positive-pressure management operating room. As a cross-over design, we used an airborne particle counter (Handheld 3016, SGY company, Tokyo) to measure the aerosols approximately 30 cm above the participant's mouth, while the volunteer was coughing, with and without the use of an air extractor Free-100 M (Forest-one, Funabashi), facing the participant's mouth. In another 20 volunteers, the aerosols were measured, while each volunteer was lying supine, without coughing, and without the use of the air extractor. RESULTS: The aerosol count during coughing was significantly lower when the air extractor was used [median: 55 (interquartile range: 15-128)] than when it was not used [73 (44-201)] [p = 0.001, difference: 19 (95%CI: 4-70)]. CONCLUSIONS: The Free-100 M air extractor would reduce, but do not remove all, aerosols produced by coughing of a patient, and thus may reduce the risk of infection of COVID-19.

Remimazolam: a randomized controlled study of its suitability for insertion of a supraglottic airway.

PURPOSE: Loss of motor response to thrusting the jaw forward is a useful indicator for uncomplicated insertion of a supraglottic airway. The aim of this study was to assess the suitability of remimazolam for insertion of a supraglottic airway assessed by loss of response to jaw thrusting. METHODS: Seventy patients, who were scheduled for elective surgeries under general anesthesia, were allocated randomly to one of two groups. In one group (remimazolam group), remimazolam was infused 12 mg kg-1 h-1 (50 mg maximum), and in the other (propofol group), propofol was infused at 120 mg kg-1 h-1 (500 mg maximum). Once the eyelash reflex disappeared, response to jaw thrusting was assessed. Primary outcome measure was the proportion of patients with loss of response to jaw thrusting before reaching the maximum dose of the test drug. We planned an interim analysis (of one time) after 40 patients, using the Pocock adjustment method. RESULTS: From the interim analysis results, the study was stopped after recruitment of 40 patients. Loss of response to jaw thrusting was observed in all of 21 patients (100%) in the propofol group, and in 9 of 19 patients (47%) in the remimazolam group. There was a significant difference in the proportion between the groups (P = 0.0001, 95% CI for difference 30-75%). CONCLUSION: Remimazolam frequently does not inhibit response to jaw thrusting, and thus remimazolam is not a suitable induction agent for uncomplicated insertion of a supraglottic airway unless either a neuromuscular blocking agent or an opioid is co-administered.

Efficacy of a surgical mask during high-flow nasal oxygen therapy in preventing aerosol dispersion: a randomized controlled study.

PURPOSE: It is not clear whether or not high-flow nasal oxygenation used in patients with severe respiratory tract infection, or coughing, increases the risk of infection to the healthcare personnel, and whether or not applying a surgical mask to the patient's face or treating the patient in a negative-pressure room can reduce the risk. METHODS: In a randomized crossover design, we compared in 50 participants receiving high-flow nasal oxygenation, the aerosol counts measured at approximately 20 cm above the participant's mouth in 32 different circumstances (with or without coughing, with or without wearing a surgical mask, at four different flow rates of oxygenation, in a positive- or negative-pressure operating room). RESULTS: In a positive-pressure room, a surgical mask significantly decreased the aerosol counts during coughing (P = 0.0005), or during no coughing (P = 0.009), under high-flow nasal oxygenation (at 60 l.min-1). In the negative-pressure room, the aerosol count was significantly lower than in the positive-pressure room, for all the circumstances (all P < 0.001), and a surgical mask significantly decreased the aerosol counts during coughing (P = 0.047) but not during no coughing (P = 0.60). CONCLUSION: In conclusion, treating a patient in a negative-pressure room, or applying a surgical mask, during high-flow nasal oxygenation (with the flow rate of 60 l.min-1) would inhibit, but would not completely prevent, dispersion of aerosols by coughing.

Efficacy of McGRATH®MAC videolaryngoscope blade 1 for tracheal intubation in small children: a randomized controlled clinical study.

BACKGROUND: Videolaryngoscopes may not be as effective in small children as they are in older children and in adults. The size 1 blade is commercially available for the McGRATH®MAC videolaryngoscope (Covidien, Medtronic, Tokyo, Japan), but its efficacy in comparison with a Macintosh laryngoscope blade 1 is not known. AIM: The main aim of this study was to assess the efficacy of McGrath®MAC blade 1 in comparison with a conventional Macintosh laryngoscope blade 1, in children aged less than 24 months. METHODS: Thirty-eight children aged less than 24 months were randomly allocated to one of two groups, and tracheal intubation was attempted using either a direct laryngoscope with a Macintosh blade 1 or a videolaryngoscope with a McGRATH®MAC blade 1. In another 12 children aged 2-4 years, the same comparisons were made with blade 2. The primary outcome measure was time to tracheal intubation using a size 1 blade. RESULTS: Tracheal intubation took significantly longer with a McGRATH®MAC blade 1 (median (interquartile range): 38.0 (31.8-43.5) s) than with the Macintosh blade 1(27.4 (25.9-29.2) s) (p < 0.0001; median difference (95% CI for the median difference): 10.6 (6.4-14.0) s), mainly due to difficulty in advancing a tube into the trachea. No significant difference was observed for the size 2. CONCLUSIONS: In small children without predicted difficult airways, time to intubate the trachea was significantly longer for a McGRATH®MAC blade 1 than a Macintosh blade 1. CLINICAL TRIAL REGISTRATION: jRCT1032220366.

Efficacy of a gastric tube insertion guide for insertion of a nasogastric tube: a prospective, randomized controlled clinical study.

PURPOSE: We studied whether a newly available gastric tube insertion guide (Fuji Medical, Tokyo, Japan) was effective in insertion of a nasogastric tube. METHODS: Sixty anesthetized patients were randomly allocated to three groups, and we attempted to insert a nasogastric tube with a blind technique (Group B), with the lateral neck pressure (Group L), or with the tube guide (Group G). If the insertion failed in Group B or L, its insertion was attempted with the tube guide. Primary outcome measure was the insertion success rate within 300 s. RESULTS: The success rate in Group G (19 of 20 patients) was significantly higher than Group L (13 of 20 patients) (P = 0.04; 95% confidence intervals for difference: 16-44%), and than Group B (11 of 19 patients) (P = 0.008; 23-50%). In the 15 patients of Groups B and L, in whom insertion had failed, insertion with the tube guide was successful in 14 patients. There was no significant difference in insertion time between the groups, but in patients in whom insertion was successful, it was significantly longer in Group G (median of 147 s) than in Group L (66 s) (P < 0.01) and Group B (46 s) (P < 0.01). Minor complications occurred in 2 patients in Group B, 1 in Group L, and 5 in Group G (P > 0.05). CONCLUSION: We conclude that the gastric tube insertion guide (Fuji Medical, Tokyo, Japan) may be useful when the conventional method of insertion has failed.

Standard of anesthesia care: possible dissociation from recommendations made by clinical practice guidelines.

A medical malpractice lawsuit may be brought against health care providers, if there was a possibility of a negligence, or failure to meet the standard of care. Recently, clinical practice guidelines have increasingly been used as evidence of the standard of care. Nevertheless, it is not clear whether these guidelines can be used as evidence of the standard of care. We carried out a snapshot study to know whether or not there were dissociations between the current standard of anesthesia care and recommendations made by clinical practice guidelines. We asked all the 80 heads of Anesthesiology departments of Japanese public and private Universities, to answer questions related to difficult airway management after induction of anesthesia, postoperative monitoring of breathing, and of the presence or the absence of neuropathy of the lower legs after regional anesthesia. The response rate was 71% (57/80). The majority of anesthesiologists had little experience with front-of-neck access in patient, and responders might frequently make repeated attempts at tracheal intubation. Postoperative monitoring was frequently not routinely performed. In conclusion, this study has shown that there may be various degrees of dissociations between the current standard of anesthesia care and the recommendations made by clinical practice guidelines that had been used as evidence of the standard of care in medical malpractice lawsuit cases in Japan.

Margin of safety for needle puncture of a radial artery.

The radial artery is the preferred site for arterial cannulation because of consistent anatomic accessibility, ease of cannulation, and a low incidence of complications. One possible risk associated with cannulation is an injury to the superficial branch of the radial nerve. The radial nerve divides to the superficial branch and the deep branch at the top of the forearm, and the superficial branch lies behind the brachioradialis muscle close to the lateral side of the radial artery and terminates the lateral side of the radial artery about 7 cm proximal to the wrist. The segment where the superficial branch of the radial nerve runs side-by-side the radial artery ("run side-by-side segment) is an increased risk area of nerve injury. We studied 100 volunteers to measure a "safe" segment (the length between the styloid process and the distal edge of the "run side-by-side segment), using an ultrasonograph. The 95%reference interval (which indicates the central 95% of a reference population) of the "safe" segment was 6.8-11.6 cm [with the mean 9.4 (standard variation: 1.7)] in men, and 5.4-11.0 [8.2 (1.4)] cm in women. In conclusion, we have shown that the margin of safety for needle puncture of a radial artery is about 6.8 cm from the wrist for in men, and 5.4 cm from the wrist for in women.

Rocuronium Bromide Intravenous Solution Maruishi® is more suitable than ESLAX Intravenous® during rapid-sequence induction of anesthesia.

PURPOSE: Rocuronium Bromide Intravenous Solution® (Maruishi Pharmaceutical Co., Ltd, Osaka, Japan) is a newly developed generic drug and we have noticed that compared with conventional rocuronium formulations [e.g. Esmeron (Eslax), MSD Co. Ltd., Tokyo, Japan], rocuronium Maruishi appeared to cause less pain or withdrawal movement. The aim of this study was to assess the hypothesis that the injection of rocuronium Maruishi causes less body movement than rocuronium MSD does, during rapid-sequence induction of anesthesia. METHODS: Sixty patients were allocated randomly to one of two groups. In one group, rocuronium MSD was used and in the other group, rocuronium Maruishi was used. After induction of general anesthesia, a test drug (containing rocuronium) 0.9 mg/kg was injected. Patient's withdrawal movement was graded with the scale. Primary outcome measure was the incidence of moderate or severe movement after the injection of rocuronium. Secondary outcome measure was the degree of movement between the groups. RESULTS: Moderate or severe withdrawal movement was observed after the injection of rocuronium MSD in 11 of 30 patients (37%) and after the injection of rocuronium Maruishi in 3 of 30 patients (10%). There was a significant difference in the incidence between the groups (P = 0.013, 95% CI for difference 26-28%). The degree of movement was also significantly greater for rocuronium MSD than for rocuronium Maruishi (P = 0.015). CONCLUSION: Compared with rocuronium MSD, rocuronium Maruishi is more suitable than conventional rocuronium formulations, for rapid-sequence induction of anesthesia.

Anatomical basis for simultaneous block of greater and third occipital nerves, with an ultrasound-guided technique.

PURPOSE: In some headache disorders, for which the greater occipital nerve block is partly effective, the third occipital nerve is also suggested to be involved. We aimed to establish a simple technique for simultaneously blocking the greater and third occipital nerves. METHODS: We performed a detailed examination of dorsal neck anatomy in 33 formalin-fixed cadavers, and deduced two candidate target points for blocking both the greater and third occipital nerves. These target points were tested on three Thiel-fixed cadavers. We performed ultrasound-guided dye injections into these points, examined the results by dissection, and selected the most suitable injection point. Finally, this target point was tested in three healthy volunteers. We injected 4 ml of local anesthetic and 1 ml of radiopaque material at the selected point, guided with a standard ultrasound system. Then, the pattern of local anesthetic distribution was imaged with computed tomography. RESULTS: We deduced that the most suitable injection point was the medial head of the semispinalis capitis muscle at the C1 level of the cervical vertebra. Both nerves entered this muscle, in close proximity, with little individual variation. In healthy volunteers, an anesthetic injected was confined to the muscle and induced anesthesia in the skin areas innervated by both nerves. CONCLUSIONS: The medial head of the semispinalis capitis muscle is a suitable landmark for blocking the greater and third occipital nerves simultaneously, by which occipital nerve involvement in various headache disorders may be rapidly examined and treated.

[The Use of a Tracheal Tube for Guiding Nasogastric Tube Insertion].

An obese patient was scheduled for shoulder joint surgery under general anesthesia. After induction of anesthesia and tracheal intubation, insertion of a gastric tube was difficult. A new tracheal tube was prepared, the connecter was removed, and the tube was cut longitudinally. The tube was inserted orally into the esophagus. A gastric tube was passed through the nose, and its tip was taken out of the mouth. The tip of the gastric tube was passed through the tracheal tube, and its correct position in the stomach was confirmed by auscultation of the epigastrium. The tracheal tube was carefully taken out from the esophagus leaving the gastric tube in the stomach. The cut tracheal tube was peeled off from the gastric tube. Correct positioning of the gastric tube was re-confirmed.

[Complication and Anesthetics-induced Toxicity of Stellate Ganglion Block].

Stellate ganglion block (SGB) is a commonly used safe procedure. In rare cases, it is associated with life- threatening complications [retropharyngeal hematomas (RPH), local anesthetics-induced toxicity, et al.). Man- agement and preventive measures of these complica- tions are described. RPH after SGB necessitates emer- gency airway management Intoxication is mainly the result of accidental intra- arterial injection and is difficult to treat but higher doses of intravenous lipid emulsions can improve the outcome.

[Anesthetic Management of an Infant who Underwent Awake-intubation for Her Pharyngeal Injury Caused by a Toothbrush].

A 2-year-and-4-month-old female infant, 12 kg in weight and 90 cm in height fell off from a table, which was about 1 m height with a toothbrush in her mouth without her parents noticing. Urgent CT scan showed that it penetrated the left side of her oropharyngeal wall to the bifurcation of her right carotid artery. According to the initial assessment, carotid artery seemed intact and there seemed to be no sign of CNS involvement. She underwent general anesthesia for further investigation and operation. We could detect vocal code with ease by inserting Glidescope between her tongue and the toothbrush. After the intubation, we administered fentanyl 25 µg rocuronium 15 mg and sevoflulane 3-5% to her, and then she underwent arteriography. The neurosurgeon found no sign of major arterial injury nor traumatic aneurysm nor CNS involvement. She went to the ICU intubated after the removal of the toothbrush. She was extubated 5 days after operation. One of the benefits of the Glidescope is that we can share the visual image, and we chose it this time. When we expect a difficult airway during management for oropharyngeal trauma, we have to consider the way to manage the airway.

[Morphine-induced Anaphylaxis before Induction of Anesthesia].

We describe a case of anaphylaxia that occurred in a 67-year-old man. He was planned to have an operation on mitral valve prolapse (MVP) for mitral regurgitation (MR). Morphine 5 mg was injected intramusculaly 45 min before operation. Since then, he felt itchy sensation around his inguinal region. After he came to the operating room, he felt itchy sensation all over the body. Initially, his vatal signs were stable. We started to give extracellular fluid including ulinastatin 300,000 U, methylprednisolone 2 g, and ranitidine 50 mg. A few minutes later, he had nettle rash all over the body and his blood pressure decreased to 40/20 mmHg, and the heart rate increased to 120 beats x min(-1). Soon after, he had pulseless electric activity (PEA). We started chest compression and tracheal intubation. We injected adrenaline 1 mg. After doing the continuous chest compression for 2 min, he revived. He had continuous medications including dopamine 5 µg x kg(-1) x min(-1), dobutamine 5 µg x kg(-1) x min(-1), noradrenaline 0.05 µg x kg(-1) x min(-1). We cancelled the operation, and he was transfered to the high care unit (HCU), where his blood pressure was 120/65 mmHg, and heart rate 120 beats x min(-1). After 24 hours, we extubated his trachea. In this case, morphine was considered to be the most likely cause for anaphylaxis.

[Anesthetic Management of a Pregnant Woman Undergoing Cesarean Section and Intestinal Tract Perforation Restoration].

We describe anesthetic management of a pregnant woman (weight 42 kg, height 147 cm) with ileus, requiring emergency cesarean section and ileus operation. Cesarean section was performed under spinal anesthesia and epidural anesthesia, and ileus operation was performed under total intravenous general anesthesia. During ileus operation, the blood pressure decreased to 60/30 mmHg and the heart rate increased to 140 beats x min, indicating the intestinal traction syndrome. Repeated injections of phenylephrine 0.1 mg and albumin preparation 5% 1,500 ml were required to restore blood pressure. After the operation, the patient's trachea was extubated. The last level of the spinal anesthesia was T6.

[Pentax AWS-s200: Its Advantages and Possible Problems].

The Pentax AWS-s200 (Hoya, Japan : s-200) is a new videolaryngoscope. Its weight is 190 g, and it is lighter than the original AWS (AWS-s100L: s-100). It has a USB port, and its screen is wider and clearer than the s-100. The INTROCK for the s-100 is all usable with the s-200. The target mark is positioned at the center of the screen in the s-200. We used the s-200 in 20 patients, and could see a full view of the glottis, and tracheal intubation was successful in all patients. But tracheal intubation was not smooth in 10 of 20 patients, mainly because the tube impacted the right arytenoid. We felt the target mark of the s-200 may be incorrectly positioned.

[Stroke Volume Variation (SVV) as an Indicator of Intraoperative Transfusion Management during Laparoscopic Colectomy.]

BACKGROUND: Intraoperative transfusion manage- ment is difficult during laparoscopic surgery, because peumoperitoneum affects hemodynamics. We studied whether stroke volume variation (SVV) is useful as an indicator of transfusion management Methods : We studied 44 patients undergoing lapa- roscopic colectomy. Patients were randomly allocated to two groups, and the volume of transfusion was decided with the SVV as an indicator in one group (SVV group, n=22) or with conventional indicators, such as blood pressure, heart rate, volume of urine in the other group (control group, n=22) Results : In the SVV group, total transfusion volume and total blood loss during operation were significantly decreased, and the length of hospital stay was signifi- cantly shorter, compared with the control group. CONCLUSIONS: We believe that the SVV is a useful indicator of intraoperative transfusi6h management during laparoscopic colectomy.