The Parker Flex-Tip™ tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster

Efficacy and airway complications of Parker Flex-Tip tubes and standard endotracheal tubes during airway manipulation: A meta-analysis and trial sequential analysis

BACKGROUND

Despite reported superior intubation outcomes associated with Parker Flex-Tip (PFT) tubes compared with those associated with standard polyvinylchloride tubes, the efficacy and safety of PFT tubes remain uncertain.

OBJECTIVES

To compare the intubation outcomes between PFT and conventional standard polyvinylchloride tubes.

DESIGN

Meta-analysis of randomised controlled trials.

DATA SOURCES

Embase, Medline, Google Scholar, PubMed and the Cochrane controlled trials register from inception until 3 January 2021.

ELIGIBILITY CRITERIA

All randomised trials comparing intubation outcomes between PFT (PFT group) and standard polyvinylchloride (standard polyvinylchloride group) tubes.

RESULTS

Analysis of the 13 eligible trials showed no significant difference in successful first-attempt intubation rate [risk ratio (RR) 1.20, 95% confidence interval (CI) 0.99 to 1.44] (6 trials, 568 participants), trauma risk (RR 0.83, 95% CI 0.67 to 1.03) (5 trials, 501 participants) as well as the overall risks of epistaxis (RR 0.58, 95% CI 0.26 to 1.31) (3 trials, 262 participants), sore throat (RR 0.90, 95% CI 0.70 to 1.17) (4 trials, 451 participants) and hoarseness (RR 0.71, 95% CI 0.44 to 1.14) (4 trials, 451 participants) between the two groups. However, the intubation time was slightly shorter (weighted mean difference -4.2 s, 95% CI -7.4 to -1.0 s) (8 trials, 759 participants) and the risks of severe epistaxis (RR 0.15, 95% CI 0.03 to 0.84) (3 trials, 262 participants) and overall difficulty in airway manipulation (RR 0.48, 95% CI 0.29 to 0.80) (8 trials, 647 participants) were lower in the PFT group than those in the standard polyvinylchloride group. Trial sequential analysis conclusively confirmed a shorter intubation time with PFT tubes than with standard polyvinylchloride tubes, whereas other intubation outcomes were inconclusive.

CONCLUSION

The use of PFT tubes for airway manipulation was associated with a shorter intubation time compared with the standard polyvinylchloride tubes. The results of trial sequential analysis suggest the need for further trials and meta-analysis to compare other intubation outcomes associated with the two devices.

TRIAL REGISTRATION

PROSPERO CRD42020197670.

Difficult tracheal tube passage and subglottic airway injury during intubation with the GlideScope® videolaryngoscope: a randomised, controlled comparison of three tracheal tubes

Difficulty during placement of the tracheal tube is a known problem when intubating with the GlideScope^® , which may lead to subglottic airway injury. This randomised, controlled clinical trial was designed to compare the resistance to passage of PVC (polyvinyl chloride), reinforced or BlockBuster tracheal tubes during intubation with the GlideScope. Secondary outcomes included the time taken to intubate and assessment of subglottic airway injury. One-hundred and seventy-seven patients were included in the data analysis. There was difficult tracheal tube passage (moderate or severe resistance) in 15 (21.4%) patients using the PVC tube compared with 4 (7.4%) and 1 (1.9%) using the reinforced and BlockBuster tubes, respectively (p = 0.003 for PVC vs. BlockBuster). The median (IQR [range]) time taken to intubate was 35 (27-45 [15-115]) s, 25 (20-27 [15-110]) s and 25 (22-30 [16-90]) s, respectively, (p < 0.001 for PVC vs. reinforced as well as PVC vs. BlockBuster). Subglottic airway injury, assessed using a fibreoptic bronchoscope after extubation, was higher with the PVC tube (p < 0.001) and the reinforced tube (p = 0.012) compared with the BlockBuster tube. We conclude that the BlockBuster tracheal tube is a better choice for orotracheal intubation with the GlideScope than PVC or reinforced tubes.

Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation

BACKGROUND

Successful tracheal intubation during general anaesthesia traditionally requires a line of sight to the larynx attained by positioning the head and neck and using a laryngoscope to retract the tongue and soft tissues of the floor of the mouth. Difficulties with intubation commonly arise, and alternative laryngoscopes that use digital and/or fibreoptic technology have been designed to improve visibility when airway difficulty is predicted or encountered. Among these devices, a rigid videolaryngoscope (VLS) uses a blade to retract the soft tissues and transmits a lighted video image to a screen.

OBJECTIVES

Our primary objective was to assess whether use of videolaryngoscopy for tracheal intubation in adults requiring general anaesthesia reduces risks of complications and failure compared with direct laryngoscopy. Our secondary aim was to assess the benefits and risks of these devices in selected population groups, such as adults with obesity and those with a known or predicted difficult airway.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase on 10 February 2015. Our search terms were relevant to the review question and were not limited by outcomes. We carried out clinical trials register searches and forward and backward citation tracking. We reran the search on 12 January 2016; we added potential new studies of interest from the 2016 search to a list of 'Studies awaiting classification', and we will incorporate these studies into the formal review during the review update.

SELECTION CRITERIA

We considered all randomized controlled trials and quasi-randomized studies with adult patients undergoing laryngoscopy performed with a VLS or a Macintosh laryngoscope in a clinical, emergency or out-of-hospital setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data, consulting a third review author to resolve disagreements. We used standard Cochrane methodological procedures, including assessment of risk of bias.

MAIN RESULTS

We included 64 studies identified during the 2015 search that enrolled 7044 adult participants and compared a VLS of one or more designs with a Macintosh laryngoscope. We identified 38 studies awaiting classification and seven ongoing studies. Of the 64 included studies, 61 included elective surgical patients, and three were conducted in an emergency setting. Among 48 studies that included participants without a predicted difficult airway, 15 used techniques to simulate a difficult airway. Seven recruited participants with a known or predicted difficult airway, and the remaining studies did not specify or included both predicted and not predicted difficult airways. Only two studies specifically recruited obese participants. It was not possible to blind the intubator to the device, and we noted a high level of inevitable heterogeneity, given the large number of studies.Statistically significantly fewer failed intubations were reported when a VLS was used (Mantel-Haenszel (M-H) odds ratio (OR), random-effects 0.35, 95% confidence Interval (CI) 0.19 to 0.65; 38 studies; 4127 participants), and fewer failed intubations occurred when a VLS was used in participants with an anticipated difficult airway (M-H OR, random-effects 0.28, 95% CI 0.15 to 0.55; six studies; 830 participants). We graded the quality of this evidence as moderate on the basis of the GRADE system. Failed intubations were fewer when a VLS was used in participants with a simulated difficult airway (M-H OR, random-effects 0.18, 95% CI 0.04 to 0.77; nine studies; 810 participants), but groups with no predicted difficult airway provided no significant results (M-H OR, random-effects 0.61, 95% CI 0.22 to 1.67; 19 studies; 1743 participants).Eight studies reported on hypoxia, and only three of these described any events; results showed no differences between devices for this outcome (M-H OR, random-effects 0.39, 95% CI 0.10 to 1.44; 1319 participants). Similarly, few studies reported on mortality, noting no differences between devices (M-H OR, fixed-effect 1.09, 95% CI 0.65 to 1.82; two studies; 663 participants), and only one study reporting on the occurrence of respiratory complications (78 participants); we graded these three outcomes as very low quality owing to lack of data. We found no statistically significant differences between devices in the proportion of successful first attempts (M-H OR, random-effects 1.27, 95% CI 0.77 to 2.09; 36 studies; 4731 participants) nor in those needing more than one attempt. We graded the quality of this evidence as moderate. Studies reported no statistically significant differences in the incidence of sore throat in the postanaesthesia care unit (PACU) (M-H OR, random-effects 1.00 (95% CI 0.73 to 1.38); 10 studies; 1548 participants) nor at 24 hours postoperatively (M-H OR random-effects 0.54, 95% CI 0.27 to 1.07; eight studies; 844 participants); we graded the quality of this evidence as moderate. Data combined to include studies of cross-over design revealed statistically significantly fewer laryngeal or airway traumas (M-H OR, random-effects 0.68, 95% CI 0.48 to 0.96; 29 studies; 3110 participants) and fewer incidences of postoperative hoarseness (M-H OR, fixed-effect 0.57, 95% CI 0.36 to 0.88; six studies; 527 participants) when a VLS was used. A greater number of laryngoscopies performed with a VLS achieved a view of most of the glottis (M-H OR, random-effects 6.77, 95% CI 4.17 to 10.98; 22 studies; 2240 participants), fewer laryngoscopies performed with a VLS achieved no view of the glottis (M-H OR, random-effects 0.18, 95% CI 0.13 to 0.27; 22 studies; 2240 participants) and the VLS was easier to use (M-H OR, random-effects 7.13, 95% CI 3.12 to 16.31; seven studies; 568 participants).Although a large number of studies reported time required for tracheal intubation (55 studies; 6249 participants), we did not present an effects estimate for this outcome owing to the extremely high level of statistical heterogeneity (I2 = 96%).

AUTHORS' CONCLUSIONS

Videolaryngoscopes may reduce the number of failed intubations, particularly among patients presenting with a difficult airway. They improve the glottic view and may reduce laryngeal/airway trauma. Currently, no evidence indicates that use of a VLS reduces the number of intubation attempts or the incidence of hypoxia or respiratory complications, and no evidence indicates that use of a VLS affects time required for intubation.

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

I-gel Versus LMA-Fastrach Supraglottic Airway for Flexible Bronchoscope-Guided Tracheal Intubation Using a Parker (GlideRite) Endotracheal Tube: A Randomized Controlled Trial

BACKGROUND

The I-gel (IG) supraglottic airway device is a reliable way to establish an airway. Its large ventilation lumen allows for easy passage of an endotracheal tube. With the use of a flexible bronchoscope, the IG offers a good visualization of the laryngeal inlet. This prospective randomized study aims to compare the success rate of flexible bronchoscope-guided tracheal intubation using either the IG or the LMA-Fastrach (FT) laryngeal masks.

METHODS

One hundred twenty patients requiring general anesthesia were randomized to 1 of the 2 study groups: IG or FT. After anesthesia induction, the assigned laryngeal mask was inserted to obtain adequate ventilation. We then proceeded to a flexible bronchoscope-guided intubation through the supraglottic device. Tracheal intubation and laryngeal mask insertion success rates were noted, as well as the time required for these manipulations. The view of the laryngeal inlet was graded for each intubation attempt.

RESULTS

Sixty patients were assigned to each study group. The intubation success rates were similar between the IG and the FT groups (100 % vs 95.0 % at first attempt; P = 0.12). The times required for tracheal intubation were significantly lower in the IG group (30 ± 11 seconds vs 50 ± 21 seconds; P < 0.0001). Glottic visualization was better in the IG group, with a significantly higher percentage of grade 1 visualization (63.3% vs 3.3%; P < 0.0001) and a lower percentage of grade 3 visualization (1.7% vs 60.0%; P < 0.0001), than that in the FT group.

CONCLUSIONS

The use of the IG supraglottic airway device as a conduit for flexible bronchoscope-guided tracheal intubation results in a success rate equivalent to the use of the LMA-FT. However, the IG allows for shorter intubation times and a better visualization of the glottic opening compared with the LMA-FT.

Comparison of Parker-tipped and Murphy-tipped tracheal tubes in Airway Scope-assisted intubation in a manikin

PURPOSE

We tested our hypothesis that a Parker-tipped tracheal tube could improve the reliability of tracheal tube passage as compared to a Murphy-tipped tracheal tube during Airway Scope-assisted intubation in a manikin.

METHODS

Twenty-seven resident doctors performed Airway Scope-assisted intubations using both tracheal tubes, and the number of times the tracheal tube tip touched the glottis or other laryngeal structures was counted on the Airway Scope monitor.

RESULTS

The incidence of the tracheal tube tip touching the glottis during Airway Scope-assisted intubation using the Parker-tipped tracheal tube (7.4%; 2 of 27 attempts) was significantly less than that obtained using the Murphy-tipped tracheal tube (33.3%; 9 of 27 attempts; P = 0.039).

CONCLUSION

When the advancement of a conventional tracheal tube during Airway Scope-assisted intubation is likely to result in collision with the glottis or other laryngeal structures, the selection of a Parker-tipped tracheal tube is a better option.