Differences in the epidermal pain threshold between different needle puncture sites.

PURPOSE: Puncture of the skin by a needle, such as for peripheral nerve block or for intravenous or arterial catheter placement, may cause pain to the patient, so that analgesic method may be required to reduce pain caused by needle puncture. Nevertheless, there is little information as to which puncture sites are more painful than the other. METHODS: After obtaining an approval of the study by a research ethics committee and written informed consent from all the participants, we studied 30 volunteers to quantify pain threshold at 13 skin sites of the body, using an algometer. RESULTS: Compared with pain threshold at the cubital fossa (which was regarded as the control value), the relative pain threshold was significantly lower (with clinically meaningful difference) at the lateral carpus (median (interquartile range): 0.66 (0.56-0.73)) and the medial carpus (0.80 (0.73-0.94)); and was significantly higher (with clinically meaningful difference) at the olecranon (2.08 (1.93-2.42)), the forehead (1.59 (1.46-1.74)), the upper shoulder (1.52 (1.38-1.79)), and the dorsal shoulder (1.39 (1.18-1.55)). CONCLUSIONS: We conclude that there are significant differences in pain threshold between different puncture sites. Analgesic method before needle puncture may be required at the sites where the pain threshold is relatively low.

Use of bispectral index for detection of partial cerebral hypoperfusion during cervical spine surgery: A case report.

The BIS value may decrease by cerebral hypoperfusion. We report a case in which the BIS value suddenly decreased during cervical spine surgery, which led us to find cervical screws compressing the vertebral arteries. In a 79-year-old man undergoing cervical spine surgery, the BIS suddenly decreased from about 40 to 10-20, about 4 h after the start of surgery. Intraoperative 3-dementional computed tomography indicated that both the two tips of cervical screws inserted in the 6th cervical vertebra were within bilateral transverse foramens. These cervical screws were removed, and the BIS increased immediately. The cervical screws were re-inserted again thorough the same vertebra into the bilateral transverse foramens, and the BIS decreased immediately. Postoperatively, cerebral hypoperfusion due to compression of bilateral vertebral arteries by two cervical screws was identified. The BIS may be a useful to detect cerebral hypoperfusion due to compression of the vertebral artery by a cervical screw.

Airway management in neonates and infants: European Society of Anaesthesiology and Intensive Care and British Journal of Anaesthesia joint guidelines.

Airway management is required during general anaesthesia and is essential for life-threatening conditions such as cardiopulmonary resuscitation. Evidence from recent trials indicates a high incidence of critical events during airway management, especially in neonates or infants. It is important to define the optimal techniques and strategies for airway management in these groups. In this joint European Society of Anaesthesiology and Intensive Care (ESAIC) and British Journal of Anaesthesia (BJA) guideline on airway management in neonates and infants, we present aggregated and evidence-based recommendations to assist clinicians in providing safe and effective medical care. We identified seven main areas of interest for airway management: i) preoperative assessment and preparation; ii) medications; iii) techniques and algorithms; iv) identification and treatment of difficult airways; v) confirmation of tracheal intubation; vi) tracheal extubation, and vii) human factors. Based on these areas, Population, Intervention, Comparison, Outcomes (PICO) questions were derived that guided a structured literature search. GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to formulate the recommendations based on those studies included with consideration of their methodological quality (strong '1' or weak '2' recommendation with high 'A', medium 'B' or low 'C' quality of evidence). In summary, we recommend: 1. Use medical history and physical examination to predict difficult airway management (1C). 2. Ensure adequate level of sedation or general anaesthesia during airway management (1B). 3. Administer neuromuscular blocker before tracheal intubation when spontaneous breathing is not necessary (1C). 4. Use a videolaryngoscope with an age-adapted standard blade as first choice for tracheal intubation (1B). 5. Apply apnoeic oxygenation during tracheal intubation in neonates (1B). 6. Consider a supraglottic airway for rescue oxygenation and ventilation when tracheal intubation fails (1B). 7. Limit the number of tracheal intubation attempts (1C). 8. Use a stylet to reinforce and preshape tracheal tubes when hyperangulated videolaryngoscope blades are used and when the larynx is anatomically anterior (1C). 9. Verify intubation is successful with clinical assessment and end-tidal CO2 waveform (1C). 10. Apply high-flow nasal oxygenation, continuous positive airway pressure or nasal intermittent positive pressure ventilation for postextubation respiratory support, when appropriate (1B).

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.

Airway management in neonates and infants: European Society of Anaesthesiology and Intensive Care and British Journal of Anaesthesia joint guidelines.

Airway management is required during general anaesthesia and is essential for life-threatening conditions such as cardiopulmonary resuscitation. Evidence from recent trials indicates a high incidence of critical events during airway management, especially in neonates or infants. It is important to define the optimal techniques and strategies for airway management in these groups. In this joint European Society of Anaesthesiology and Intensive Care (ESAIC) and British Journal of Anaesthesia (BJA) guideline on airway management in neonates and infants, we present aggregated and evidence-based recommendations to assist clinicians in providing safe and effective medical care. We identified seven main areas of interest for airway management: i) preoperative assessment and preparation; ii) medications; iii) techniques and algorithms; iv) identification and treatment of difficult airways; v) confirmation of tracheal intubation; vi) tracheal extubation, and vii) human factors. Based on these areas, Population, Intervention, Comparison, Outcomes (PICO) questions were derived that guided a structured literature search. GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to formulate the recommendations based on those studies included with consideration of their methodological quality (strong '1' or weak '2' recommendation with high 'A', medium 'B' or low 'C' quality of evidence). In summary, we recommend: 1. Use medical history and physical examination to predict difficult airway management (1С). 2. Ensure adequate level of sedation or general anaesthesia during airway management (1B). 3. Administer neuromuscular blocker before tracheal intubation when spontaneous breathing is not necessary (1С). 4. Use a videolaryngoscope with an age-adapted standard blade as first choice for tracheal intubation (1B). 5. Apply apnoeic oxygenation during tracheal intubation in neonates (1B). 6. Consider a supraglottic airway for rescue oxygenation and ventilation when tracheal intubation fails (1B). 7. Limit the number of tracheal intubation attempts (1C). 8. Use a stylet to reinforce and preshape tracheal tubes when hyperangulated videolaryngoscope blades are used and when the larynx is anatomically anterior (1C). 9. Verify intubation is successful with clinical assessment and end-tidal CO 2 waveform (1C). 10. Apply high-flow nasal oxygenation, continuous positive airway pressure or nasal intermittent positive pressure ventilation for postextubation respiratory support, when appropriate (1B).

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.

Fibreoptic intubation: a commitment to an indispensable technique.

Recent evidence has shown that fibreoptic intubation is still an indispensable technique for safe management of predicted difficult airways, despite the implementation of new technologies such as videolaryngoscopy. It is therefore our obligation as anaesthesia societies and as practicing anaesthetists to offer this technique to our patients in clearly designated situations.

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 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.

Preventing difficult facemask ventilation in children: all is well that starts well.

Difficult facemask ventilation at induction of general anaesthesia can trigger hypoxaemia and inadequate ventilation if not immediately identified and adequately treated. For this reason, identification of predisposing conditions before induction of anaesthesia and causes of poor facemask ventilation are critical to avoid the subsequent complications. In a recently published secondary analysis of the Paediatric Difficult Intubation (PeDI) registry, the incidence and risk factors for difficult facemask ventilation in children with difficult tracheal intubation was described, as highlighted in the editorial.

A fragmented segment of a central venous catheter caused delayed ventricular fibrillation: a case report.

BACKGROUND: Central venous port systems may be safely used for chemotherapy of patients with cancer, but several complications may occur associated with their use. CASE PRESENTATION: An 83-year-old man with heat stroke was transferred to our emergency department, where he was treated and became able to eat on the same day. He had been fit and healthy, except for colorectomy and chemotherapy using a central venous access port placed in the right upper jugular vein 8 years ago. The next day, he suddenly had ventricular fibrillation. Cardiopulmonary resuscitation was successful. Emergency coronary angiography showed a catheter-like foreign body in the coronary sinus. Physicians failed to remove the foreign body using catheter therapy, and ventricular fibrillation occurred repeatedly. After induction of general anesthesia, the fractured catheter was removed surgically. Postoperative course was uneventful. CONCLUSIONS: A fragmented segment of a catheter may suddenly cause ventricular fibrillation years later.

Efficacy of an aid (gastric tube insertion guide) for oral insertion of a gastric tube: a randomized controlled trial.

PURPOSE: Insertion of a gastric tube orally may be more difficult than its insertion nasally, and thus, any aid to facilitate its insertion may be useful. Gastric tube insertion guide (Fuji Medical Corporation, Tokyo, Japan) has recently become commercially available. We felt that this device might be useful in facilitating oral insertion of a gastric tube, but there has been no formal study assessing its efficacy. The main aim of this study was to assess whether or not this "tube guide" would facilitate insertion of an orogastric tube. METHODS: As a randomized controlled clinical study, we planned to study 40 patients, to assess the hypothesis that the success rate of insertion of an orogastric tube would be higher with the use of the "tube guide" than without. Patients were recruited when they were 20 years old, or older, and allocated randomly to one of two groups (20 people each group). In one group, the conventional "blind" insertion method was used and in the other group the "tube guide" insertion method. RESULTS: The success rate was significantly higher for the "tube guide" method than the "blind" insertion method (P = 0.0012, 95% CI for difference: 23-67%). CONCLUSION: We have shown that the use of the gastric tube insertion guide® facilitates insertion of an orogastric tube.

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.