Hemodynamic changes following endotracheal intubation with glidescope(®) video-laryngoscope in patients with untreated hypertension

A Comprehensive Review of Magnesium Sulfate Infusion: Unveiling the Impact on Hemodynamic Stability During Laryngoscopy and Tracheal Intubation in Ear, Nose, and Throat Surgeries

This comprehensive review explores the potential of magnesium sulfate infusion in mitigating hemodynamic instability during laryngoscopy and tracheal intubation in ear, nose, and throat (ENT) surgeries. Hemodynamic fluctuations during these procedures pose challenges, and magnesium sulfate, with its vasodilatory, antiarrhythmic, and neuroprotective properties, emerges as a promising intervention. The review critically examines existing literature, emphasizing patient selection criteria, dosage protocols, and a comparative analysis with other hemodynamic stabilizers. Safety considerations, including known adverse effects and risk-benefit assessments, and monitoring and management strategies are elucidated. The implications for ENT surgery are discussed, highlighting the potential for enhanced hemodynamic management and individualized approaches. The review concludes with a call for continued research, emphasizing the ongoing evolution of understanding and practice incorporating magnesium sulfate into perioperative care. The insights offered aim to guide clinicians in navigating this dynamic landscape for improved patient outcomes in ENT surgeries.

Sex Disparities in Applied Force on Maxillary Incisors Among Novices During Laryngoscopy Using a High-Fidelity Simulator: A Prospective Observational Study

Endotracheal intubation (ETI) is a common and crucial intervention. Whether the performance of ETI differs according to the sex of the laryngoscopist remains unclear. The aim of this study was to assess sex disparities in markers of ETI performance among novices using a high-fidelity simulator. This prospective observational study was conducted from April 2017 to March 2019 in a public medical university. In total, 209 medical students (4th and 5th grade) without clinical ETI experience were recruited. Of the 209 students, 64 (30.6%) were female. The participants used either a Macintosh direct laryngoscope or C-MAC video laryngoscope in combination with a stylet or gum-elastic bougie to perform ETI on a high-fidelity simulator. The primary endpoint was the maximum force applied on the maxillary incisors during laryngoscopy. The secondary endpoint was the time to ETI. The implanted sensors in the simulator automatically quantified the force and time to ETI. The maximum force applied on the maxillary incisors was approximately 30% lower in the male than female group for all laryngoscopes and intubation aids examined (all P < 0.001). Similarly, the time to ETI was approximately 10% faster in the male than female group regardless of the types of laryngoscopes and intubation aids used (all P < 0.05). In this study, male sex was associated with a lower maximum force applied on the maxillary incisors during both direct and indirect laryngoscopy performed by novices. A clinical study focusing on sex differences in ETI performance is needed to validate our findings.

Effect of electroacupuncture on haemodynamic changes during intubation for general anaesthesia is mediated by nitric oxide synthase‑3 via the regulation of microRNA‑155, microRNA‑335 and microRNA‑383

Intubation for general anaesthesia is a life‑threatening risk because it can cause haemodynamic changes. Electroacupuncture (EA) has been reported to alleviate the risk of intubation. In the present study, haemodynamic changes were measured at different time points before and after EA. Reverse transcription‑quantitative PCR was performed to measure the expression of micro (mi)RNAs and endothelial NO synthase (eNOS) mRNA. Western blotting was performed to evaluate the expression of eNOS protein. A luciferase assay was used to explore the inhibitory role of miRNAs in eNOS expression. The transfection of miRNA precursors and antagomirs was performed to assess their effect on eNOS expression. The systolic blood pressure, diastolic blood pressure and mean arterial pressure of patients were significantly decreased by EA, while the heart rate of patients was markedly increased. The expression of micro RNA (miR)‑155, miR‑335 and miR‑383 was effectively inhibited by EA in the plasma and peripheral blood monocytes of patients, whereas eNOS expression and NOS production were markedly elevated by EA. The luciferase activity of the eNOS vector was significantly inhibited by miR‑155, miR‑335 and miR‑383 mimics but activated by miR‑155, miR‑335 and miR‑383 antagomirs. miR‑155, miR‑335 and miR‑383 precursors suppressed the expression of eNOS, while miR‑155, miR‑335 and miR‑383 antagomirs enhanced the expression of eNOS. The present study demonstrated that EA may exert a vasodilative effect during intubation for general anaesthesia by promoting NO production and upregulating eNOS expression. The effect of EA on upregulating eNOS expression may be mediated by its inhibitory effect on the expression of miRNA‑155, miRNA‑335 and miRNA‑383.

Videolaryngoscopy versus direct laryngoscopy for adults undergoing tracheal intubation

BACKGROUND

Tracheal intubation is a common procedure performed to secure the airway in adults undergoing surgery or those who are critically ill. Intubation is sometimes associated with difficulties and complications that may result in patient harm. While it is traditionally achieved by performing direct laryngoscopy, the past three decades have seen the advent of rigid indirect videolaryngoscopes (VLs). A mounting body of evidence comparing the two approaches to tracheal intubation has been acquired over this period of time. This is an update of a Cochrane Review first published in 2016.

OBJECTIVES

To assess whether use of different designs of VLs in adults requiring tracheal intubation reduces the failure rate compared with direct laryngoscopy, and assess the benefits and risks of these devices in selected population groups, users and settings.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and Web of Science on 27 February 2021. We also searched clinical trials databases, conference proceedings and conducted forward and backward citation searches.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs with adults undergoing laryngoscopy performed with either a VL or a Macintosh direct laryngoscope (DL) in any clinical setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We collected data for the following outcomes: failed intubation, hypoxaemia, successful first attempt at tracheal intubation, oesophageal intubation, dental trauma, Cormack-Lehane grade, and time for tracheal intubation.

MAIN RESULTS

We included 222 studies (219 RCTs, three quasi-RCTs) with 26,149 participants undergoing tracheal intubation. Most studies recruited adults undergoing elective surgery requiring tracheal intubation. Twenty-one studies recruited participants with a known or predicted difficult airway, and an additional 25 studies simulated a difficult airway. Twenty-one studies were conducted outside the operating theatre environment; of these, six were in the prehospital setting, seven in the emergency department and eight in the intensive care unit.  We report here the findings of the three main comparisons according to videolaryngoscopy device type. We downgraded the certainty of the outcomes for imprecision, study limitations (e.g. high or unclear risks of bias), inconsistency when we noted substantial levels of statistical heterogeneity and publication bias. Macintosh-style videolaryngoscopy versus direct laryngoscopy (61 studies, 9883 participants) We found moderate-certainty evidence that a Macintosh-style VL probably reduces rates of failed intubation (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.26 to 0.65; 41 studies, 4615 participants) and hypoxaemia (RR 0.72, 95% CI 0.52 to 0.99; 16 studies, 2127 participants). These devices may also increase rates of success on the first intubation attempt (RR 1.05, 95% CI 1.02 to 1.09; 42 studies, 7311 participants; low-certainty evidence) and probably improve glottic view when assessed as Cormack-Lehane grade 3 and 4 (RR 0.38, 95% CI 0.29 to 0.48; 38 studies, 4368 participants; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.51, 95% CI 0.22 to 1.21; 14 studies, 2404 participants) but this finding was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of this evidence was very low (RR 0.68, 95% CI 0.16 to 2.89; 18 studies, 2297 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 96%). Hyperangulated videolaryngoscopy versus direct laryngoscopy (96 studies, 11,438 participants) We found moderate-certainty evidence that hyperangulated VLs probably reduce rates of failed intubation (RR 0.51, 95% CI 0.34 to 0.76; 63 studies, 7146 participants) and oesophageal intubation (RR 0.39, 95% CI 0.18 to 0.81; 14 studies, 1968 participants). In subgroup analysis, we noted that hyperangulated VLs were more likely to reduce failed intubation when used on known or predicted difficult airways (RR 0.29, 95% CI 0.17 to 0.48; P = 0.03 for subgroup differences; 15 studies, 1520 participants). We also found that these devices may increase rates of success on the first intubation attempt (RR 1.03, 95% CI 1.00 to 1.05; 66 studies, 8086 participants; low-certainty evidence) and the glottic view is probably also improved (RR 0.15, 95% CI 0.10 to 0.24; 54 studies, 6058 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). However, we found low-certainty evidence of little or no clear difference in rates of hypoxaemia (RR 0.49, 95% CI 0.22 to 1.11; 15 studies, 1691 participants), and the findings for dental trauma were unclear because the certainty of this evidence was very low (RR 0.51, 95% CI 0.16 to 1.59; 30 studies, 3497 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 99%). Channelled videolaryngoscopy versus direct laryngoscopy (73 studies, 7165 participants) We found moderate-certainty evidence that channelled VLs probably reduce rates of failed intubation (RR 0.43, 95% CI 0.30 to 0.61; 53 studies, 5367 participants) and hypoxaemia (RR 0.25, 95% CI 0.12 to 0.50; 15 studies, 1966 participants). They may also increase rates of success on the first intubation attempt (RR 1.10, 95% CI 1.05 to 1.15; 47 studies, 5210 participants; very low-certainty evidence) and probably improve glottic view (RR 0.14, 95% CI 0.09 to 0.21; 40 studies, 3955 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.54, 95% CI 0.17 to 1.75; 16 studies, 1756 participants) but this was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of the evidence was very low (RR 0.52, 95% CI 0.13 to 2.12; 29 studies, 2375 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 98%).

AUTHORS' CONCLUSIONS

VLs of all designs likely reduce rates of failed intubation and result in higher rates of successful intubation on the first attempt with improved glottic views. Macintosh-style and channelled VLs likely reduce rates of hypoxaemic events, while hyperangulated VLs probably reduce rates of oesophageal intubation. We conclude that videolaryngoscopy likely provides a safer risk profile compared to direct laryngoscopy for all adults undergoing tracheal intubation.

Comparison of the hemodynamic response of dexmedetomidine versus additional intravenous lidocaine with propofol during tracheal intubation: a randomized controlled study

Background

Laryngoscopy and tracheal intubation are strong stimuli that cause a reflex increase in blood pressure (BP), heart rate (HR), and serum catecholamine level. These can lead to myocardial infarction or cerebrovascular accidents. The purpose of this study is to compare the efficacy of dexmedetomidine and lidocaine combined with propofol in attenuating the hemodynamic response following laryngoscopy and endotracheal intubation.

Methods

This study was a randomized controlled study and adhered to the CONSORT guidelines. One-hundred and six patients undergoing elective general anesthesia with endotracheal intubation were divided randomly into two groups. Group D received dexmedetomidine (1 μg kg^− 1) before induction. Group LP received lidocaine (1.5 mg kg^− 1) before induction with additional propofol (0.5 mg kg^− 1) before laryngoscopy. The primary endpoint was hemodynamic including systolic (S) BP, diastolic (D) BP, mean arterial blood pressure (MAP) and HR measured before and after induction and ≤ 10 min after intubation. Secondary outcome was complications/adverse effects.

Results

After induction, the mean SBP, DBP, MAP and HR decreased significantly from baseline in both groups except for mean HR in group LP at 1 min. Differences in mean values of SBP, DBP, and MAP were significantly lower in group D after intubation at 4–10 min (P <  0.05). Group LP had a non-inferior effect in blunting BP at all time points except 1 and 2 min after induction, and 2 min after intubation. The mean difference in HR in group D was significantly lower than that in group LP at all time points (P <  0.001). Group D had significantly more episodes of bradycardia (18.87% vs. 0%, P = 0.001) and hypotension (52.83% vs. 15.09%, P < 0.001) than did group LP.

Conclusion

Lidocaine (1.5 mg kg^− 1) with additional propofol (0.5 mg kg^− 1) had a non-inferior effect compared with dexmedetomidine (1 μg kg^− 1) in attenuating the hemodynamic response following laryngoscopy and endotracheal intubation, and had fewer adverse effects.

Trial registration

Thai Clinical Trial Registry, (TRTC20190206002). Retrospectively registered 4 February 2019.

Haemodynamic responses following orotracheal intubation in patients with hypertension---Macintosh direct laryngoscope versus Glidescope®videolaryngoscope

BACKGROUND AND AIMS

Glidescope®videolaryngoscope (GVL) is a video intubation system with 60° angle blade that provides excellent laryngeal view, does not require alignment of oral, pharyngeal, and laryngeal axes for visualisation of glottis, thus causing less stimulation of orolaryngopharynx. The aim of this study was to compare haemodynamic responses (blood pressure and heart rate) and airway morbidity using the Macintosh direct laryngoscope (MDL) and the Glidescope®videolaryngoscope (GVL) in hypertensive patients.

METHODS

Fifty patients with hypertension controlled on antihypertensive medications scheduled for elective surgery under general anaesthesia were randomly assigned to group GVL (n = 25) or group MDL (n = 25). Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) were recorded at baseline, after induction, pre-intubation, at intubation, 1, 2, 3, 4, and 5 min after intubation. Time to intubation, number of attempts, complications during intubation, and postoperative airway complications (sore throat, hoarseness, dysphagia, and cough) were also recorded.

RESULTS

There was a statistically significant increase in SBP, DBP, and MBP at intubation [(P = 0.003, 0.013, 0.03), 1 min (P = 0.001, 0.012, 0.02), 2 min (P = 0.04, 0.02, 0.04), and 3 min (P = 0.02, 0.01)] in the MDL group as compared to GVL group. The time to intubate was significantly greater in the GVL group as compared to MDL group (P = 0.0006). There was no significant difference in the incidence of intraoperative and postoperative airway complications.

CONCLUSION

In the hands of an experienced anaesthesiologist, the use of GVL in controlled hypertensive patients is associated with less haemodynamic response as compared to Macintosh Laryngoscope without any increase in airway complications.

Use of the GlideScope does not lower the hemodynamic response to tracheal intubation more than the Macintosh laryngoscope: a systematic review and meta-analysis

BACKGROUND

It is presently unclear whether the hemodynamic response to intubation is less marked with indirect laryngoscopy using the GlideScope (GlideScope) than with direct laryngoscopy using the Macintosh laryngoscope. Thus, the aim of this study was to determine whether using the GlideScope lowers the hemodynamic response to tracheal intubation more than using the Macintosh laryngoscope.

METHODS

We performed a comprehensive literature search of electronic databases for clinical trials comparing hemodynamic response to tracheal intubation. The primary aim was to determine whether the heart rate (HR) and mean blood pressure (MBP) 60 s after tracheal intubation with the GlideScope were lower than after intubation with the Macintosh laryngoscope. We expressed pooled differences in HR and MBP between the devices as the weighted mean difference with 95% confidence interval and also performed trial sequential analysis (TSA). Second, we examined whether use of the GlideScope resulted in lower post-intubation hemodynamic responses at 120, 180, and 300 s compared with use of the Macintosh laryngoscope. For sensitivity analysis, we used a multivariate random effects model that accounted for within-study correlation of the longitudinal data.

RESULTS

The literature search identified 13 articles. HR and MBP at 60 seconds post-intubation was not significantly lower with the GlideScope than with the Macintosh (HR vs MBP: weighted mean difference = 0.22 vs 2.56; 95% confidence interval -3.43 to 3.88 vs -0.82 to 5.93; P = .90 vs 0.14; I = 77% vs 63%: Cochran Q, 52.7 vs 27.2). Use of the GlideScope was not associated with a significantly lower HR or MBP at 120, 180, or 300 s post-intubation. TSA indicated that the total sample size was over the futility boundary for HR and MBP. Sensitivity analysis indicated no significant association between use of the GlideScope and a lower HR or MBP at any measurement point.

CONCLUSIONS

Compared with the Macintosh laryngoscope, the GlideScope did not lower the hemodynamic response after tracheal intubation. Sensitivity analysis results supported this finding, and the results of TSA suggest that the total sample size exceeded the TSA monitoring boundary for HR and MBP.

Randomized Prospective Comparison of Glidescope Video Laryngoscope with Macintosh Laryngoscope in Adult who Underwent Thyroid or Parathyroid Surgery Using Neuromonitorization

Objectives

The present study aims to compare the effects of Glidescope Video Laryngoscope (GVL) and Machintosh Laryngoscope (ML) on the hemodynamic response, intubation time and mucosal damage in adult patients who underwent thyroid or parathyroid surgery using neuromonitorization.

Methods

In this study, 180 patients, aged between 22 and 65 classified as Class I-II in ASA (American Society of Anesthesiologists) and operated under elective conditions were included. Patients were assigned into two groups: Patients intubated with GVL Group G (n=90) and patients intubated with ML Group M (n=90). In both groups, intubation time and the number of trials were recorded. HR (Heart Rate), SpO2 (Peripheral Capillary Oxygen Saturation), SBP (Systolic Blood Pressure), DBP (Diastolic Blood Pressure) and MBP (Mean Blood Pressure) scores were recorded at preinduction, post-induction, post-intubation and three minutes after intubation. Post-operative intubation-associated complications were recorded.

Results

Post intubation HR, DBP and MBP scores were found to be significantly higher in Group M than Group G (p=0,006, p=0.013, p=0.011). Intubation time was found to be significantly higher in Group G than in group M (35.3±10.3, 22.1±7.7 sec). There was no significant difference between the groups' number of trials and intubation-associated complications.

Conclusion

Despite its long intubation time, we believe that GVL may be the first choice laryngoscopy method in the thyroid or parathyroid cases that intubated with a low dose muscle relaxant for neuromonitoring since it has a slight effect than ML on hemodynamism it does not increase mucosal damage and has improved visibility.

Lower maximum forces on oral structures when using gum-elastic bougie than when using endotracheal tube and stylet during both direct and indirect laryngoscopy by novices: a crossover study using a high-fidelity simulator

BACKGROUND

Applying excessive force during endotracheal intubation (ETI) is associated with several complications, including dental trauma and hemodynamic alterations. A gum-elastic bougie (GEB), a type of tracheal tube introducer, is a useful airway adjunct for patients with poor laryngoscopic views. However, how the use of a GEB affects the force applied during laryngoscopy is unclear. We compared the force applied on the oral structures during ETI performed by novices using the GEB versus an endotracheal tube + stylet.

METHODS

This prospective crossover study was conducted from April 2017 to March 2019 in a public medical university in Japan. In total, 209 medical students (4th and 5th grade, mean age of 23.7 ± 2.0 years) without clinical ETI experience were recruited. The participants used either a Macintosh direct laryngoscope (DL) or C-MAC video laryngoscope (VL) in combination with a GEB or stylet to perform ETI on a high-fidelity airway management simulator. The order of the first ETI method was randomized to minimize the learning curve effect. The outcomes of interest were the maximum forces applied on the maxillary incisors and tongue during laryngoscopy. The implanted sensors in the simulator quantified these forces automatically.

RESULTS

The maximum force applied on the maxillary incisors was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (39.0 ± 23.3 vs. 47.4 ± 32.6 N, P < 0.001) and C-MAC VL (38.9 ± 18.6 vs. 42.0 ± 22.1 N, P < 0.001). Similarly, the force applied on the tongue was significantly lower when using a GEB than when using an endotracheal tube + stylet both with the Macintosh DL (31.9 ± 20.8 vs. 37.8 ± 22.2 N, P < 0.001) and C-MAC VL (35.2 ± 17.5 vs. 38.4 ± 17.5 N, P < 0.001).

CONCLUSIONS

Compared with the use of an endotracheal tube + stylet, the use of a GEB was associated with lower maximum forces on the oral structures during both direct and indirect laryngoscopy performed by novices. Our results suggest the expanded role of a GEB beyond an airway adjunct for difficult airways.

Comparison of hemodynamic responses to endotracheal intubation with the GlideScope video laryngoscope and Macintosh laryngoscope in patients undergoing cardiovascular surgery

Background

This study aimed to compare hemodynamic response to endotracheal intubation using GlideScope and Macintosh laryngoscopes in patients who underwent cardiovascular surgery.

Methods

A total of 74 patients were enrolled in the study. Patients were randomly assigned into two groups either a GlideScope (n=37) or a Macintosh laryngoscope (n=37). Laryngoscopy time, heart rate, invasive arterial pressure and rate pressure product were compared during induction and until five minutes after laryngoscopy at 11 time points.

Results

Seventy patients completed the study. The intubation time was similar in both groups (14.1±4.0 sec vs. 13.2±4.2 sec; p=0.22). Hemodynamic values including heart rate, systolic, diastolic and mean arterial pressure and rate pressure product were similar at all-time points. The laryngoscopy time was also similar between groups.

Conclusion

The GlideScope video laryngoscope did not show any advantage on hemodynamic response in patients undergoing cardiovascular surgery when compared to Macintosh laryngoscope.

Longitudinal acquisition of endotracheal intubation skills in novice physicians

Little is known about the acquisition of intubation skills among novice physicians during their one-year clinical training. Our primary objective was to determine the changes in the intubation skills of novice physicians between prior to the clinical training and after completion of the clinical training. We used data of a prospective longitudinal multicenter data registry developed to investigate factors associated with the improvement of intubation skills among novice physicians. The study participants included 90 postgraduate year 1 physicians in 2015–2016. We used 4 simulation scenarios based on the devices used (direct laryngoscope [DL] and Airway scope [AWS]) and difficulty of intubation (normal and difficult scenarios). As a marker of the intubation skills, we used the force applied on the maxillary incisors and the tongue with each intubation. We compared the data obtained prior to clinical training with those obtained after completion of one-year clinical training. When using DL, compared to prior, significantly less force were applied on the maxillary incisors and the tongue after clinical training in the normal scenario (28.0 N vs 19.5 N, p < 0.001, and 11.1 N vs 8.4 N, p = 0.004). Likewise, when using AWS, compared to prior, significantly less force were applied on the tongue after clinical training in the normal scenario (22.0 N vs 0 N, p < 0.001). The force on the tongue decreased after clinical training but not significant. These associations persisted in the difficult airway scenario. These findings suggest that force applied on oral structures can be quantified as a marker of intubation skills by using high-fidelity simulators, and the assessment of procedural competency is recommended for all novice physicians prior to performing intubation in the clinical setting to improve the quality of emergency care.

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.

Comparison of the force applied on oral structures during intubation attempts by novice physicians between the Macintosh direct laryngoscope, Airway Scope and C-MAC PM: a high-fidelity simulator-based study

OBJECTIVE

We examined whether the use of Airway Scope (AWS) and C-MAC PM (C-MAC) decreased the force applied on oral structures during intubation attempts as compared with the force applied with the use of Macintosh direct laryngoscope (DL).

DESIGN

Prospective cross-over study.

PARTICIPANTS

A total of 35 novice physicians participated.

INTERVENTIONS

We used 6 simulation scenarios based on the difficulty of intubation and intubation devices.

OUTCOME MEASURES

Our primary outcome measures were the maximum force applied on the maxillary incisors and tongue during intubation attempts, measured by a high-fidelity simulator.

RESULTS

The maximum force applied on maxillary incisors was higher with the use of the C-MAC than with the DL and AWS in the normal airway scenario (DL, 26 Newton (N); AWS, 18 N; C-MAC, 52 N; p<0.01) and the difficult airway scenario (DL, 42 N; AWS, 24 N; C-MAC, 68 N; p<0.01). In contrast, the maximum force applied on the tongue was higher with the use of the DL than with the AWS and C-MAC in both airway scenarios (DL, 16 N; AWS, 1 N; C-MAC, 7 N; p<0.01 in the normal airway scenario; DL, 12 N; AWS, 4 N; C-MAC, 7 N; p<0.01 in the difficult airway scenario).

CONCLUSIONS

The use of C-MAC, compared with the DL and AWS, was associated with the higher maximum force applied on maxillary incisors during intubation attempts. In contrast, the use of video laryngoscopes was associated with the lower force applied on the tongue in both airway scenarios, compared with the DL. Our study was a simulation-based study, and further research on living patients would be warranted.

Effect of Etomidate Versus Combination of Propofol-Ketamine and Thiopental-Ketamine on Hemodynamic Response to Laryngoscopy and Intubation: A Randomized Double Blind Clinical Trial

BACKGROUND

Laryngoscopy and intubation frequently used for airway management during general anesthesia, is frequently associated with undesirable hemodynamic disturbances.

OBJECTIVES

The aim of this study was to compare the effects of etomidate, combination of propofol-ketamine and thiopental-ketamine as induction agents on hemodynamic response to laryngoscopy and intubation.

PATIENTS AND METHODS

In a double blind, randomized clinical trial a total of 120 adult patients of both sexes, aged 18 - 45 years, scheduled for elective surgery under general anesthesia were randomly assigned into three equally sized groups. Patients in group A received etomidate (0.3 mg/kg) plus normal saline as placebo. Patients in group B and C received propofol (1.5 mg/kg) plus ketamine (0.5 mg/kg) and thiopental sodium (3 mg/kg) plus ketamine (0.5 mg/kg), respectively for anesthesia induction. Before laryngoscopy and tracheal intubation, immediately after, and also one and three minutes after the procedures, hemodynamic values (SBP, DBP, MAP and HR) were measured.

RESULTS

A repeated measurement ANOVA showed significant changes in mean SBP and DBP between the time points (P < 0.05). In addition, the main effect of MAP and HR were statistically significant during the course of study (P < 0.05). Furthermore, after induction of anesthesia, the three study groups had significantly different SBP, DBP and MAP changes overtime (P < 0.05). However, HR changes over time were not statistically significant (P > 0.05). Combination of propofol-ketamine had superior hemodynamic stability compared to other induction agents.

CONCLUSIONS

Combination of propofol-ketamine may be recommended as an effective and safe induction agent for attenuating hemodynamic responses to laryngoscopy and intubation with better hemodynamic stability. Although, further well-designed randomized clinical trials to confirm the safety and efficacy of this combination, especially in critically ill patients or patients with cardiovascular disease, are warranted.

Comparison of GlideScope video laryngoscopy and Macintosh laryngoscope in ear-nose and throat surgery

AIM

Endotracheal intubation procedure employed during general anaesthesia is the most effective way for keeping the airways and respiration under control and has low risk of complications. We have aimed in this study to compare the first-attempt success and duration of the endotracheal intubation process and its effects on haemodynamics using the Macintosh laryngoscope and the GlideScope video laryngoscope.

METHODS

In this prospective randomized single-centre study, 100 patients of 18-65 years of age, and classified within the American Society of Anaesthesiologists' (ASA) I-II risk groups before elective ear-nose and throat surgery were included. The patients were randomly divided into two groups, designated as Group M, to be intubated using the Macintosh laryngoscope, and as Group G, to be intubated using the GlideScope video laryngoscope. The Mallampati scores, Cormack-Lehane classifications, intubation duration, number of attempts at intubation, the haemodynamic response and the complications were recorded.

RESULTS

There were not intergroup differences with respect to the number of intubation attempts, the Mallampati and Cormack-Lehane classifications. Duration of intubation was found to be longer in group G. The haemodynamic response values of group M were higher than those of group G. Although there was no statistically significant difference between the two groups in the number of intubation attempts, two of the patients in group M were intubated in the second attempt.

CONCLUSION

In our study, despite the longer intubation times in group G, the haemodynamic response was significantly lower in this group. It is believed that especially in cases with vital requirement of haemodynamic stability, the GlideScope video laryngoscope would be safer to employ.

Hemodynamic changes following endotracheal intubation in patients undergoing cesarean section with general anesthesia: application of glidescope® videolaryngoscope versus direct laryngoscope

Background

Endotracheal intubation is usually associated with hemodynamic changes, especially in patients undergoing cesarean section by general anesthesia. GlideScope® videolaryngoscope (GVL) is a novel video laryngoscope, which does not need direct exposure of vocal cords and produces lesser hemodynamic changes due to lower degrees of trauma and stimuli to oropharynx than the Macintosh direct laryngoscope (MDL).

Objectives

The aim of this study was to compare hemodynamic changes following endotracheal intubation with GVL and MDL in patients undergoing cesarean section by general anesthesia.

Materials and Methods

Seventy patients undergoing elective cesarean section by general anesthesia requiring endotracheal intubation were randomly allocated to be intubated with either GVL (n = 35) or MDL (n = 35). Systolic, diastolic and mean arterial blood pressure (MAP), as well as pulse rates, and rate pressure product (RPP) were compared at baseline, after induction of anesthesia, and after intubation at one-minute interval for five minutes between the two groups. The patients were also compared for Mallampati score, sore throat, intubation time and neonates’ Apgar scores.

Results

The patients were similar regarding systolic, diastolic and mean arterial blood pressure. Pulse rate changes were significantly lower only at 1 and 3 minutes in the GVL group. The intubation times were 9.3 ± 1.4 and 10.6 ± 1.7 seconds in the MDL and GVL groups, respectively (P > 0.05). RPP was also lower in the GVL group at 1 and 2 minutes (P < 0.05) and returned to baseline afterwards. There was no significant difference between the groups for Mallampati score, sore throat and Apgar scores.

Conclusions

Our study revealed that hemodynamic parameters with GVL are only better preserved in the first three minutes after intubation in patients undergoing elective cesarean section and patients are similar regarding intubation time, sore throat and Apgar score.