Fibreoptic nasal intubation in children with anticipated and unanticipated difficult intubation

The establishment of a tracheal airway with direct laryngoscopy can be either a very difficult or an impossible task in children with congenital or acquired facial malformations. Out of 46 patients categorized as difficult tracheal intubation, fibreoptic laryngoscopy was used successfully in 44 children anaesthetized by mask with sevoflurane and oxygen or by an intravenous infusion of propofol and mask oxygenation. There were two failures (4.3%). One was due to excessive bleeding and secretions produced by the multiple attempts to intubate with direct laryngoscopy and the other failure in a patient with Pierre Robin syndrome and very small nasal passages that precluded the introduction of the endoscope. Fibreoptic laryngoscopy was successful in 37 cases (80.4%) on the first attempt to intubate and in seven (15.2%) on a second or third attempt. We conclude that fibreoptic laryngoscopy in anaesthetized children with difficult anticipated or unanticipated tracheal intubation in trained hands is a safe technique that can be lifesaving. Therefore, we urge all anaesthesia trainees to become proficient in fibreoptic tracheal intubation.     

Delayed upper airway obstruction A life-threatening complication of Dettol poisoning

Dettol liquid is a commonly used household disinfectant and although it is labelled nonpoisonous, serious respiratory complications have been reported in up to 8% of cases of Dettol ingestion. We report a case in which the delayed onset of upper airway obstruction was treated with emergency awake, fibreoptic guided nasotracheal intubation. Based on information available in published cases and on our own experience, we suggest that patients who have ingested large volumes of Dettol, have a history of vomiting or unprotected lavage, or have evidence of ongoing oropharyngeal inflammation, are at high risk of this complication. They should be closely observed for at least 48 h after ingestion and the facilities and staff required for emergency airway management should be immediately available.     

Learning curves for fibreoptic nasotracheal intubation when using the endoscopic video camera

We have followed the progress of 12 anaesthetic trainees as they learnt how to perform fibreoptic nasotracheal intubation with the aid of an endoscopic video camera system. Each trainee had a structured teaching session on a bronchial tree model, viewed an instructional videotape and then performed 20 nasotracheal intubations on anaesthetised oral surgery patients. Trainees were required to perform the endoscopies under full visual control and to demonstrate airway anatomy as they advanced the fibrescope. They were allowed up to two 2½ min periods to complete nasotracheal endoscopy. All 240 endoscopies were completed within the time limit: 228 were completed within 2½ min and 12 (5%) were completed during the second 2½ min period. We constructed a group learning curve from the pooled data. The half-life of the curve was nine endoscopies. The best fit value for the first endoscopy time was 132 s, and after the 18th (two half-lives) it was 49 s. We analysed the theoretical basis for deriving a learning curve from raw data. This information could form a rational basis for the design of fibreoptic training programmes using video imaging systems.     

Effect of the size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation

We randomly allocated 60 patients with normal airways into three groups to compare the ease of fibrescope-aided tracheal intubation using 8.0-mm internal diameter (group F₈) and 6.0-mm (group F₆) reinforced tracheal tubes and to evaluate the efficacy of the laryngeal mask as an aid for fibreoptic tracheal intubation (group L). In group F₈ tracheal intubation was optimal in 2 of 20 patients and in two patients in whom intubation over the fibrescope was difficult the attempts resulted in inadvertent oesophageal intubation. In group F₆ intubation was always successful and significantly easier than in group F₈ (p < 0.005; 95% confidence interval for the difference in the proportion of the optimal intubation grade: 20–70%). In group L tracheal intubation was optimal in 18 of 20 patients and easier than in group F₆ (p = 0.014; 95% confidence interval for difference: 10–60%). In both groups F₆ and L tracheal intubation was completed within less than about 1 min. We conclude that conventional fibrescope-aided tracheal intubation with a 6.0-mm tracheal tube is easier than with an 8.0-mm tube and that the laryngeal mask facilitates fibrescope-aided tracheal intubation.     

A modified Guedel airway for continuous oxygenation and suctioning during fibreoptic bronchoscopy

We describe a modification to the Guedel airway that improves suction and oxygenation during fibreoptic bronchoscopy. The entire roof of a Guedel airway was removed. Two 2.5-mm internal diameter tracheal tubes were inserted into the modified airway to allow continuous oxygen delivery and suction throughout fibreoptic bronchoscopy. It was tested as a single-use device in ten patients undergoing awake fibreoptic bronchoscopy under sedation and topical anasthesia. During the procedure there were no problems with either fogging of the lens or secretions in the pharynx. In addition, oxyhaemoglobin saturation, as monitored continuously by pulse oximetry, was >/= 97% in all patients.     

Oxygen saturation and cardiovascular changes during fibreoptic intubation under general anaesthesia

Sixty patients who required fibreoptic nasotracheal intubation were studied. Arterial oxygen saturation, arterial blood pressure and heart rate were monitored continuously during fibreoptic intubation under deep halothane anaesthesia. There were significant decreases (p less than 0.001) in arterial blood pressure and heart rate despite administration of intravenous colloid and atropine. Almost one third of the patients (18 out of 60) suffered a decrease in arterial oxygen saturation below 90% during the intubation sequence and in five patients the saturation fell below 80%. The episodes of desaturation were not related to the induction-intubation time or to the grade of laryngeal visibility at direct laryngoscopy.     

A randomised clinical trial comparing the flexible fibrescope and the Pentax Airway Scope (AWS)® for awake oral tracheal intubation

We compared awake fibreoptic intubation with awake intubation using the Pentax Airway Scope^® in 40 adult patients. Sedation was achieved using a target‐controlled remifentanil infusion of 1–5 ng.ml^?1 and midazolam. The airway was anaesthetised with lidocaine spray and gargle. The total procedure time – a composite of sedation time, topical anaesthesia time and intubation time – was recorded. The operator's impression of the ease of the procedure and the patients' reported comfort were recorded on a 0–100 mm visual analogue scale. The median (IQR [range]) for total procedure time was 900 (739–1059 [616–1215]) s with the fibrescope and 651 (601–720 [498–900]) s with the Pentax Airway Scope (p = 0.0001). The median (IQR [range]) intubation time was 420 (283–480 [120–608]) s with the fibrescope and 183 (144–220 [107–420]) s with the Pentax Airway Scope (p = 0.0002). The median (IQR [range]) visual analogue scores for the operator's ease of intubation for the fibrescope and Pentax Airway Scope were 83.6 (72.0–98.0 [49.0–100.0]) and 86.8 (84.0–91.0 [61.0–100.0]), respectively (p = 0.3507). The median (IQR [range]) visual analogue score for patient comfort was 85.5 (81.0–97.0 [69.0–100.0]) and 79.4 (74.0–85.0 [59.0–100.0]) for the fibrescope and Pentax Airway Scope, respectively (p = 0.06). Total procedure time was significantly shorter with the Pentax Airway Scope compared with the fibrescope, with no difference in procedure difficulty or patient discomfort.     

The effect of introducing fibreoptic bronchoscopes on gas flow in laryngeal masks and tracheal tubes

The laryngeal mask airway, reinforced laryngeal mask airway and tracheal tube were studied to determine (1) flow resistance during simulated inspiration and (2) the maximum size of fibreoptic scope which can he passed down the lumen at clinically useful ventilatory settings. In addition, the flow resistance imposed by the mask aperature bars was quantified. The laryngeal mask airway can accommodate a larger fibrescope than the corresponding sizes of reinforced laryngeal mask airway or tracheal tube. Mean (range)flow resistance was 2.3 (1.7-35) times higher with the reinforced laryngeal mask airway compared to the laryngeal mask airway, 2.1 (1.2-4.2) times higher with the tracheal tube compared with the laryngeal mask airway and 1.2 (0.7-1.8) times lower with the tracheal compared with the reinforced laryngeal mask airway. Removal of the mask aperture bars resulted in a mean decrease in flow resistance of 3.6%. Our data have shown that the laryngeal mask airway can accommodate a larger fibrescope than either the reinforced laryngeal mask airway or tracheal tube at clinically useful ventilatory settings and that the current recommendations for maximum size of fibrescope should be revised.     

The laryngeal mask airway for fibreoptic bronchoscopy in children

A size 2 laryngeal mask airway (ID 7 mm) was used for general anaesthesia during fibreoptic bronchoscopy in a six-year-old child. The mask permitted the use of an adult bronchoscope with an external diameter of 5 mm. Throughout bronchoscopy, adequate controlled ventilation could be achieved easily without excessive air leak or airway resistance; the Spo₂ was always > 97%, and the endtidal Pco₂ ranged between 3·9–4·5 kPa (30–35 mmHg).     

To surgeons and physicians

The subscriber is prepared to furnish a person fully competent to administer his compound to patients who are to have surgical operations performed, and when it is desired by the Operator that the patient should be rendered insensible to pain. Personal or written application may be made toW. T. G. MORTON,Dentist,No. 19, Tremont Row, Boston.     

Incidence,causes, and management of failed awake fibreoptic intubation—A retrospective study of 833 procedures

Awake fibreoptic intubation has been considered a gold standard in the management of the difficult airway. However, failure may cause critical situations. The aim of this study was to investigate the incidence and causes of failed awake fibreoptic intubation at a tertiary care hospital. The study was conducted at St. Olav University Hospital in Trondheim, Norway. Problems occurring during anaesthesia are routinely recorded in the electronic anaesthesia information system (Picis Clinical Solutions Inc.), including difficult intubations. We applied text search on all anaesthesia records between 2011 and 2021 and identified 833 awake fibreoptic intubations. The anaesthesia records were examined to identify failed awake fibreoptic intubations, the cause of failure and how the airway ultimately was secured. Among 233,938 patients who received anaesthesia, 90,397 received tracheal intubation and 833 received awake fibreoptic intubation. Twenty-nine of the procedures failed. In nine patients the failure caused loss of airway control with desaturation and hypoventilation. The major causes of failure were dislodged tube after induction of general anaesthesia (n = 8), patient distress (n = 5), tube not able to pass (n = 5), and airway bleeding (n = 3). The situations were primarily solved using direct laryngoscopy, with or without bougie, or with video laryngoscopy. Tracheostomy was performed in four patients. Awake fibreoptic intubation failed in 3.5% of patients, most often due to dislocation, problems passing the tracheal tube, or patient discomfort. The failure rate was higher than in previous studies.     

Retrograde tracheal intubation: beyond fibreoptic endotracheal intubation

BACKGROUND: Flexible fibreoptic laryngoscopy is the method of choice for coping with difficult tracheal intubations, a leading cause of catastrophic outcomes in anaesthesia. However, this technique is not always available or feasible. Retrograde intubation is a minimally invasive airway management technique with a flat learning curve and a high level of skill retention. METHODS: A retrospective review of the anaesthesia records of 24 patients who underwent retrograde intubation. The success rate and the incidence of complications were recorded. RESULTS: Retrograde tracheal intubation was successful in all 24 patients. In 21 patients it succeeded on the first attempt. In two patients it succeeded when the technique was changed from sliding over a guide wire to a pulling technique. The most common complication was a sore throat in almost 60% of the patients. Two patients had mild subcutaneous emphysema and one had minimal bleeding at the puncture site. CONCLUSIONS: In these patients retrograde tracheal intubation was easy to perform, had a high success rate and a low incidence of complications. It is a reliable alternative when fibreoptic intubation is precluded, fails or is unavailable.     

Attenuating the hypertensive response to laryngoscopy and endotracheal intubation using awake fibreoptic intubation

Blood pressure and pulse rate measurements were recorded in 35 patients undergoing endotracheal intubation during general anaesthesia (Group A), and 35 patients who had an awake fibreoptic intubation under local anaesthesia (Group B). The mean arterial pressure in Group A rose by a mean of 35 mmHg immediately after intubation, compared with a mean fall of 9 mmHg in Group B. The mean pulse rate in Group A rose by 24 beats per minute (b.p.m.) immediately after intubation, compared with a rise of 3 b.p.m. in Group B. Both these differences were statistically significant (P less than 0.0001 and P less than 0.001 respectively, Mann Whitney U test). Postoperative discomfort was assessed 24 h later by means of linear analogue scales. There was a statistically higher mean score in relation to nose discomfort in Group B (P less than 0.002). Awake fibreoptic intubation successfully reduces the pressor response to endotracheal intubation in normotensive adults. It is suitable for use in those patients who are at risk from the pressor response.     

Complete airway obstruction during awake fibreoptic intubation

Awake fibreoptic intubation is well established as the optimum method of securing the airway in patients in whom difficulty is anticipated. We report a patient undergoing awake fibreoptic intubation in whom the use of topical local anaesthetic precipitated acute loss of the airway so that urgent surgical intervention was required.     

瑞芬太尼在纤维支气管镜清醒气管插管中的应用进展

背景 困难气道患者的围术期气道管理是临床麻醉关注的热点问题.纤维支气管镜清醒气管插管(awake fibreoptic intubation,AFO1)技术是处理预见性困难气道的公认方法.然而实施AFOI的难点在于给患者提供充分镇静、镇痛的同时,又要保证患者有效的自主通气功能.瑞芬太尼作为一种较理想的麻醉性镇痛药,一定剂量下能有效抑制气管插管的应激反应,故已有用于AFOI的报道. 目的 概述及评价瑞芬太尼在AFOI中的有效性及安全性,为临床应用和进一步研究提供参考. 内容 分析瑞芬太尼用于AFOI的剂量对机体的影响、不同给药方案的优劣以及在特殊患者中的应用. 趋向 瑞芬太尼在AFOI中的应用具有诸多优势,但最佳方案仍需进一步临床研究.     

In vivo spasmolytic effect of ketamine and adrenaline on histamine-induced airway constriction

Background : Ketamine (K) has been reported to produce bronchodilation in patients suffering from asthma. Although most researchers have used indirect measurements to study the effect of K in vivo, the reliability of these indirect methods are controversial. We have developed a new technique to measure the bronchial cross-sectional area (BCA) in vivo with a superfine fibreoptic bronchoscope (SFB). Employing this method, we evaluated in vivo spasmolytic effect of K and adrenaline (A). Methods : Twenty-one mongrel dogs were anaesthetized with pentobarbitone (30 mg . kg^-1) and paralyzed with pancuronium (200μg . kg^-1 . h^-1). The trachea was intubated with an endotracheal tube that has a second lumen for insertion of a SFB (OD: 2.2 mm) to measure the BCA continuously. The tip of the SFB was placed between the 2nd and 3rd bronchial bifurcation of the right lung. A videoprinter printed the BCA, which was then measured with NIH Image. Bronchoconstriction was produced with histamine (H: 10μg . kg^-1+500μg . kg^-1 . h^-1) which was administered until the end of the experiment. The BCA was assessed before and 30 min after the start of H infusion. The dogs were randomly allocated to 3 groups of 7 dogs each. In group K, K (0–10 mg . kg^-1) was given i.v., and the BCA was measured 5 min after each K dose. In group A, A (0-0.4μg . kg^-1) was given i.v., and the BCA was measured 1 min after each A dose. In group A+K, K (1 mg . kg^-1 i.v. +1 mg . kg^-1 . h^-1 i.v.) was given followed, 30 min after, by A i.v. in the same doses as in group A. The BCA was assessed 30 min after the start of K and again 1 min after each A dose. Results : K 10 mg . kg^-1 reversed H-induced bronchoconstriction. A subthreshold dose of K significantly potentiated the effect of A, reversing the decrease in BCA by H. Conclusion : We have found that K could reverse the H-induced bronchoconstriction and potentiate the A-induced bronchial relaxation.