Low alfentanil target-concentrations improve hemodynamic and intubating conditions during induction with sevoflurane

Evaluation of the Hemodynamic Response to Endotracheal Intubation Comparing the Airtraq(®) with Macintosh Laryngoscopes in Cardiac Surgical Patients

Introduction:

Cardiac patients are more prone to develop hemodynamic instability on induction of anesthesia and endotracheal intubation. The Airtraq^® optical laryngoscope is a single-use rigid video laryngoscope that has been developed to facilitate tracheal intubation. There are limited studies comparing differences in the circulatory responses to Airtraq^® and direct Macintosh larynngoscopy in cardiac patients.

Aim:

The purpose of our study was to evaluate whether there was clinically significant difference between the hemodynamic response to orotracheal intubation guided by either of the two devices (Airtraq^® and Macintosh laryngoscopes) in patients who underwent coronary artery bypass grafting surgery.

Material and methods:

In this clinical study we analyzed the hemodynamic response to endotracheal intubation performed with Airtraq^® or Macintosh laryngoscopes in patients who underwent elective coronary artery bypass graft surgery under general anesthesia.

Results:

We analyzed: blood pressure (systolic, diastolic, mean), heart rate and peripheral oxygen saturation (all notified before induction in anesthesia, immediately after induction, at the time of intubation and thereafter one and five minutes after intubation). We also recorded the maximal values of blood pressure and heart rate, as well as calculated the product of heart rate and systolic blood pressure. There were statistically significant differences in the hemodynamic response between the groups. At the time of intubation, there was significant inter-group difference in heart rate, systolic, diastolic and mean blood pressure. Endotracheal intubation with Macintosh laryngoscope was accompanied by significant increase in blood pressure and heart rate compared to Airtraq^® group.

Conclusion:

The Airtraq^® laryngoscope performed better than the Macintosh laryngoscope in terms of hemodynamic to the patient undergoing routine coronary artery bypass graft surgery.

[Prospective trial comparing Airtraq and Glidescope techniques for intubation of obese patients]

OBJECTIVES

Videolaryngoscope techniques are more and more in use and tend to modify our approach for patients difficult to intubate. We compared two techniques, Airtraq and Glidescope with direct laryngoscopy, with special emphasis on ease of access to airway (Intubation Difficulty Score - IDS score, duration and success of intubation) and the impact on hemodynamic variables among patients with a BMI of more than 30.

STUDY DESIGN

Prospective study randomised with minimisation technique.

MATERIAL AND METHODS

Eighty patients have been allocated by minimisation to four groups: two groups being intubated with Airtraq, each one with a different investigator, and two with Glidescope videolaryngoscope technique. Induction of anesthesia was standardly performed with total intravenous anesthesia with remifentanil, propofol in TCI mode and rocuronium in bolus. Following parameters were recorded : intubation success based on intubation time and desaturation level, its duration, its impact on hemodynamic variables, IDS score and possible dental lesions.

RESULTS

Intubation success was 100% for Glidescope and 80.6% for Airtraq (P=0.009). Airtraq allowed a better visualisation of the vocal cords (lower Cormack and Lehane score) than Glidescope. In contrast, alternative intubation techniques were significantly more often used in the Airtraq group. No difference could be detected between both systems on hemodynamic parameters.

CONCLUSIONS

In obese patients, Glidescope allows intubation relatively easily without rescue techniques.

Low-dose fentanyl-midazolam combination improves sevoflurane induction in adults

PURPOSE

We investigated the effects of a combination of low-dose fentanyl-midazolam premedication on the speed of inhaled induction with sevoflurane and ProSeal laryngeal mask airway (PLMA) insertion conditions.

METHODS

Eighty adult patients undergoing elective surgery were randomized in a double-blind fashion to receive either a normal saline placebo (Group PLAC) or a fentanyl 0.6 microg x kg(-1) and midazolam 9 microg x kg(-1) premedication (Group FM) 5 min before tidal volume sevoflurane 8%/O(2) induction. Anxiety levels, times to loss of eyelash reflex (LER) and PLMA insertion, and cardiorespiratory data were recorded.

RESULTS

Times to LER (Group PLAC: 66 +/- 34 sec vs Group FM: 47 +/- 18 sec, P = 0.0027, difference = 19 sec: 95% confidence interval [CI] 7-31 sec) and to PLMA insertion (Group PLAC: 186 +/- 80 sec vs Group FM: 119 +/- 44 sec, P < 0.0001, difference = 68 sec: 95% CI 39-97 sec) were shorter following FM. After PLMA insertion, end-tidal sevoflurane concentration (EtSevo) was lower and end-tidal CO(2) (EtCO(2)) was higher following FM. Respiratory rate (RR) was lower with FM, but there was no difference regarding tidal volume. Adverse events, such as movements and apnea, occurred more often in Group PLAC. Systolic blood pressure (SBP) and heart rate (HR) during induction were both lower with FM. Anxiety level after premedication was lower following FM administration. All participants remembered the face mask being applied in Group PLAC vs 69% in Group FM, P < 0.0001.

CONCLUSION

Administration of a low-dose fentanyl-midazolam combination prior to sevoflurane induction decreases time to LER and allows for more rapid and less eventful PLMA insertion. Both SBP and HR were lower when premedication was administered. Patients receiving premedication were less anxious and less likely to remember the face mask. However, premedication was associated with a lower RR and increased EtCO(2) values following PLMA insertion, in spite of lower EtSevo concentrations. (ClinicalTrials.gov ID NCT00723164).

The optimal bolus dose of alfentanil for tracheal intubation during sevoflurane induction without neuromuscular blockade in day-case anaesthesia

BACKGROUND

The purpose of this study was to determine the optimal bolus dose of alfentanil required to provide successful intubating conditions following inhalation induction of anaesthesia using 5% sevoflurane and 60% nitrous oxide without neuromuscular blockade in adult day-case anaesthesia.

METHODS

Twenty-four adults, aged 18-60 years, undergoing general anaesthesia for short ambulatory surgery were enroled into the study. After vital capacity induction, with sevoflurane 5% and 60% nitrous oxide in oxygen, pre-determined dose of alfentanil was injected over 30 s. The dose of alfentanil was determined by modified Dixon's up-and-down method (2 microg/kg as a step size). Ninety seconds after the end of bolus administration of alfentanil, the trachea was intubated. Systolic blood pressure, heart rate and SpO2 were recorded at anaesthetic induction, before, 1 min and 3 min after intubation.

RESULTS

The bolus dose of alfentanil for successful tracheal intubation was 10.7+/-2.1 microg/kg in 50% of patients during inhalation induction. From probit analysis, 50% effective dose (ED(50)) and ED(95) values (95% confidence limits) of alfentanil were 10.7 microg/kg (8.0-12.9 microg/kg) and 14.9 microg/kg (12.9-31.1 microg/kg), respectively.

CONCLUSIONS

Using the modified Dixon's up-and-down method, the bolus dose of alfentanil for successful tracheal intubation was 10.7+/-2.1 microg/kg in 50% of adult patients during inhalation induction using 5% sevoflurane and 60% nitrous oxide in oxygen without neuromuscular blocking agent in day-case anaesthesia.

Endotracheal Intubation in Patients with Cervical Spine Immobilization

Background:

The Airtraq laryngoscope (Prodol Ltd., Vizcaya, Spain) is a novel single-use tracheal intubation device. The authors compared ease of intubation with the Airtraq and Macintosh laryngoscopes in patients with cervical spine immobilization in a randomized, controlled clinical trial.

Methods:

Forty consenting patients presenting for surgery requiring tracheal intubation were randomly assigned to undergo intubation using a Macintosh (n = 20) or Airtraq (n = 20) laryngoscope. All patients were intubated by one of four anesthesiologists experienced in the use of both laryngoscopes.

Results:

No significant differences in demographic or airway variables were observed between the groups. All but one patient, in the Macintosh group, were successfully intubated on the first attempt. The Airtraq reduced the duration of intubation attempts (mean ± SD: 13.2 ± 5.5 vs. 20.3 ± 12.2 s), the need for additional maneuvers, and the intubation difficulty scale score (0.1 ± 0.5 vs. 2.7 ± 2.5). Tracheal intubation with the Airtraq caused fewer alterations in blood pressure and heart rate.

Conclusions:

These findings demonstrate the utility of the Airtraq laryngoscope for tracheal intubation in patients with cervical spine immobilization.

A comparison of tracheal intubation using the Airtraq�or the Macintosh laryngoscope in routine airway management: a randomised, controlled clinical trial

The Airtraq laryngoscope is a novel single use tracheal intubation device. We compared the Airtraq with the Macintosh laryngoscope in patients deemed at low risk for difficult intubation in a randomised, controlled clinical trial. Sixty consenting patients presenting for surgery requiring tracheal intubation were randomly allocated to undergo intubation using a Macintosh (n = 30) or Airtraq (n = 30) laryngoscope. All patients were intubated by one of four anaesthetists experienced in the use of both laryngoscopes. No significant differences in demographic or airway variables were observed between the groups. All but one patient, in the Macintosh group, was successfully intubated on the first attempt. There was no difference between groups in the duration of intubation attempts. In comparison to the Macintosh laryngoscope, the Airtraq resulted in modest improvements in the intubation difficulty score, and in ease of use. Tracheal intubation with the Airtraq resulted in less alterations in heart rate. These findings demonstrate the utility of the Airtraq laryngoscope for tracheal intubation in low risk patients.

Induction par inhalation de sévoflurane à objectif de concentration chez l'adulte avec le respirateur ZEUS®

OBJECTIVES

To evaluate if the new anaesthesia platform ZEUS (Dräger Medical) allows the induction of anaesthesia with target-controlled inhalation of sevoflurane.

STUDY DESIGN

Prospective clinical study.

PATIENTS

Adult ASA I or II patients scheduled for elective surgery under general anaesthesia.

METHODS

After preoxygenation during 3 min at 100% oxygen, patients were asked to breathe normally; the target end-tidal concentration of sevoflurane was fixed at 4% without priming of the circuit. Sufentanil (target concentration 0.5 ng/ml) was administered 40 s after.

RESULTS

Ten patients (48+/-22 yrs) were included. Sevoflurane was detected in the circuit after 36+/-5 s; the target end-tidal concentration of sevoflurane was obtained at 130+/-19 s. Loss of consciousness was observed after 119+/-7 s. The induction was achieved in all patients without any incident.

CONCLUSION

This new anaesthesia system make available the induction of anaesthesia with sevoflurane without priming of the circuit.