Does salivary pH affect postoperative sore throat in the head-down position of general anesthesia?

BACKGROUND: Tracheal intubation sometimes causes postoperative sore throat (POST) due to laryngeal damage. However, clinical observations suggest that the environment of the oral cavity may also affect POST. OBJECTIVE: The purpose of this study was to investigate whether salivary pH in the oral cavity affects POST. METHODS: After obtaining ethical approval, informed consent was obtained from all patients. Patients who underwent surgery in the supine position were enrolled as the control group. Patients who underwent laparoscopic surgery in the head-down position were enrolled as the intervention group. Immediately before both groups of patients were anaesthetised, expelled saliva was collected, and salivary pH was measured. Immediately postoperatively, the same measurement was carried out before the patient regained consciousness. The primary outcome was the change in salivary pH. The secondary outcome was POST. In our study, POST was defined as pharyngeal and swallowing pain in the glossopharyngeal and superior laryngeal nerves. The normal distribution of pH was tested using the Shapiro-Wilk test followed by analysis using repeated-measurements and one-way analysis of variance. Statistical significance was set at p < .05. RESULTS: A total of 62 patients were enrolled, of whom two were excluded based on the exclusion criteria. Salivary pH in the intervention group was significantly lower than that in the control group. Five patients had POST in the intervention group, whereas none had POST in the control group had POST. CONCLUSION: Acidotic-shifted saliva is considered one of the causes of POST.

Challenge to pediatric anatomical variation : Can we draw the ideal line on the pediatric I-gel?

OBJECTIVE: I-gel is a noncuff type of laryngeal airway mask. No horizontal line has yet been determined as an ideal position for pediatric sizes because of the variability in length of the oropharyngeal-laryngeal arch in children. We investigated whether there is a correlation between insertion length and patient body weight or height for the pediatric I-gel sizes from 1.5 to 2.5. METHODS: With parental informed consent, we planned to maintain the airway of 130 children aged from 7 months to 13 years by using the I-gel device under general anesthesia. The following two parameters were evaluated: (1) distance between the teeth and the connector wing; (2) insertion length (distance from the distal end of the gastric tube to the teeth). Size selection was determined on the basis of patients' body weight. We identified the relationship between each parameter and height or weight. RESULTS: Average insertion length became gradually longer with increasing height and weight. Spearman's R between insertion length and height or weight was 0.8. There was more correlation with height than with weight in pediatric size 2.5. CONCLUSION: Results suggested that it is possible to draw an ideal line on the I-gel with sizes 1.5 and 2 only.

Ultrasound versus anatomical landmarks for caudal epidural anesthesia in pediatric patients.

BACKGROUND: Caudal block is easily performed because the landmarks are superficial. However, the sacral hiatus is small and shallow in pediatric patients. In the present study, we evaluated under general anesthesia whether the distance between the bilateral superolateral sacral crests increased with growth, whether an equilateral triangle was formed between the apex of the sacral hiatus and the bilateral superolateral sacral crests, and whether expansion of the epidural space could be confirmed by ultrasound. METHODS: This prospective observational study included 282 children who were ASA I-II. Under general anesthesia, each patient was placed in the lateral bent knees position, and the attending anesthesiologist drew an equilateral triangle and measured the distance between the bilateral superolateral sacral crests along a line forming the base of the triangle. Then the sacral hiatus was identified by ultrasound. Differences of the distance between the anatomical landmarks measured by the anesthetist and by ultrasound were evaluated. RESULTS: Two patients were excluded because the superolateral sacral crests and sacral hiatus could not be palpated. The base of the triangle increased in proportion to age up to 10 years old, with a significant correlation between age and the length of the base (Spearman's r value = 0.97). The triangle was not an equilateral triangle under 7 years old. The sacral hiatus could be identified by ultrasound and we could confirm expansion of the epidural space in all patients. CONCLUSION: We observed a correlation between age and the length of the triangle base in children under 10 years old. Although detection of the anatomical landmarks by palpation differed from identification by ultrasound in pediatric patients, performing ultrasound is important. Epinephrine should be added to the anesthetic to avoid complications. TRIAL REGISTRATION: Current Controlled Trials UMIN000017898 . Registered 14 June 2015. Date of protocol fixation was 1(st) December, 2008 and Anticipated trial start date was 5(th) January, 2009.

Changes of epidural blood flow after epidural administration of epinephrine in young rats.

PURPOSE: For caudal epidural analgesia, the needle is inserted at a site where vessels are abundant. To avoid complications related to intravascular administration of the local anesthetic, epinephrine is usually added, but there is no evidence about the safety of epidural administration of epinephrine in pediatric patients. The objective of this study was to assess the changes in epidural blood flow after epidural injection of epinephrine in young rats. METHODS: With approval of the local ethics committee, four young Sprague-Dawley rats weighing 110-120 g were investigated. The rats were anesthetized with isoflurane via a mask. After there was no escape reaction to pain, an arterial catheter, epidural blood flow monitor (Laser Doppler blood flow ALF 21; ADVANCE Corp.), and caudal epidural catheter were inserted while the rats remained under general anesthesia. Exactly, 10 µl of 1 : 1000 epinephrine was then infused, followed by measurement of the blood pressure and epidural blood flow. After the recovery of the blood pressure and epidural blood flow to baseline, 10 µl of saline was infused through the epidural catheter. The blood pressure and epidural blood flow were then measured again. RESULTS: One rat was excluded because epinephrine was inadvertently injected into the epidural vessels. Therefore, three rats were investigated in this experiment. Blood flow in the epidural space showed no change after the injection of saline. When epinephrine was administered into the epidural space, epidural blood flow decreased immediately and low flow persisted for 6-15 min. The reduction of blood flow was not very great, being only 8-14%, so there was no risk of spinal ischemia which would require 60-80% reduction. CONCLUSION: Administration of epinephrine into the epidural space was safe in young rats. While reduction of epidural blood flow was observed, there was no spinal ischemia.

The use of a scented face mask in pediatric patients may facilitate mask acceptance before anesthesia induction.

Background: Scented face masks are commonly used during the induction phase of anesthesia. The present study investigated whether the use of a scented mask improved mask acceptance before the slow induction of anesthesia in pediatric patients. Methods: This prospective, randomized controlled trial enrolled patients aged 2-10 years who were scheduled to undergo surgery under general anesthesia. Patients were randomly assigned to either of regular unscented (control group) or scented (experimental group) face masks before anesthesia induction with a parent. The primary outcome was the mask acceptance score, rated on a validated 4-point from 1 point (not afraid; easily accepts the mask) to 4 points (afraid of a mask; crying or struggling). The secondary outcome was heart rate assessed by pulse oximetry in the pediatric ward before transfer to the operating room (OR), at the entrance to the OR, at the patient notification of mask fitting by the anesthesiologist, and after mask fitting. Results: Seventy-seven patients were accessed for eligibility, with 67 enrolled in the study: 33 in the experimental group and 34 in the control group. Mask acceptance was significantly greater among patients aged 2-3 years in the experimental than in the control group (p < 0.05). Conclusion: The use of a scented mask can improve mask acceptance before anesthesia induction with a parental presence in pediatric patients aged 2-3 years.Clinical Trial Registration: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000040819.

Initial experience of the i-gel supraglottic airway by the residents in pediatric patients.

PURPOSE: Insertion of a laryngeal mask airway (LMA) is occasionally difficult in children because of their anatomical features and variations. A new single-use supraglottic airway device, the i-gel airway, was recently introduced. The objective of this study was to show the initial experience of the i-gel airway device by the residents for pediatric patients. METHODS: With approval from the local ethics committee and parental informed consent, 70 children undergoing minor surgery in the supine position, ASA score I-II, were investigated. Exclusion included patients having thoracic, neurosurgical, spine, and otolaryngological procedures. Patients were divided into three groups: group 1 was airway size 1.5 for patients weighing 5-12 kg, group 2 was size 2 for 10-25 kg, and group 3 was size 2.5 for those weighing 25-35 kg. The following seven characteristics were evaluated: (1) ease of the i-gel and gastric tube insertion; (2) leak pressure; (3) tidal volume/body weight at leak pressure point; (4) fiberscope score; (5) insertion time; (6) hypoxia rate (laryngospasm); and (7) coughing and trace of bleeding. RESULTS: The overall insertion success rate and the success rate at first attempt were 99% and 94%, respectively. Gastric tube insertions were easy in all patients. The overall leak pressure was 23 ± 5 cmH(2)O. The tidal volume per body weight was 24 ± 10 ml/kg. A good view of the fiberscope was achieved in 79%. In group 1 (size 1.5), one failed insertion, two dislocations, and one dysphonia were observed. Hypoxia rate was 1%. There was no case with coughing and trace of bleeding. CONCLUSION: These results show that the i-gel airway is a safe and effective device for use by residents who do not have experience with insertion of a pediatric LMA. However, using size 1.5, special caution should be taken to protect the infant airway, similar to what has been previously reported for other airway devices.