Laryngeal mask airway can be inserted with inhaled desflurane induction

What happens to the hemodynamic responses for laryngeal mask airway insertion when we supplement propofol with butorphanol or fentanyl for induction of anesthesia: A comparative assessment and critical review

Background:

There is a delicate balance between respiratory tract anatomy, its physiology, physiological response to anesthetic agents, and airway management. The traditional gadgets to secure airway are face masks or endotracheal tubes. Recently, laryngeal mask airway (LMA) is gaining popularity. It does not require laryngoscopy thereby minimizing hemodynamic responses. For LMA placement, propofol is the induction agent of choice. Propofol, when used alone, requires large doses and leads to undesirable cardiorespiratory depression. To culminate its dose, various adjuncts are combined with it.

Aim:

Comparison of hemodynamic response of LMA using either butorphanol or fentanyl (according to group allocated) in combination with propofol.

Methodology:

Hundred patients scheduled for various surgical procedures were randomly selected and divided into two groups of 50 patients each, Group F (propofol and fentanyl) and Group B (propofol and butorphanol). One minute after giving intravenous (IV) opioids, induction was achieved with IV propofol 2.5 mg/kg. Depth of anesthesia was assessed, and LMA was inserted. Hemodynamic variables were measured before premedication, after premedication; 1, 3, and 5 min after insertion and after extubation of LMA.

Results:

After insertion of LMA, statistically significant drop in mean heart rate, systolic blood pressure (BP), diastolic BP, and mean BP was noted in Group F as compared to Group B (P < 0.05).

Conclusion:

The use of propofol-butorphanol combination produces stable hemodynamics as compared to propofol-fentanyl combination.

The median effective dose of dexmedetomidine for laryngeal mask airway insertion with propofol 2.0 mg/kg

BACKGROUND

Dexmedetomidine can be used as a co-induction agent to facilitate laryngeal mask airway (LMA) insertion with minimal effect on respiratory function. The purpose of the study was to determine the median effective dose (ED50) of dexmedetomidine to facilitate LMA insertion during anaesthesia induction with propofol 2.0 mg/kg without neuromuscular blockade.

METHODS

Twenty-two patients, whose American Society of Anesthesiologists physical status was I or II with ages between 18 and 60 years undergoing minor orthopaedic or gynaecological surgery, were enrolled. After an injection of pre-determined bolus dose of dexmedetomidine over 2 min, anaesthesia was induced with propofol 2.0 mg/kg. The modified Dixon's up-and-down method was used to determine the bolus dose of dexmedetomidine, starting from 0.5 μg/kg (step size; 0.1 μg/kg). LMA insertion was conducted 90 s after the propofol injection, and the response of patients was categorized as either 'success' or 'failure.'

RESULTS

Insertion of the LMA was unsuccessful in 12 of 22 patients. The ED50 (95% confidence interval) of dexmedetomidine for successful LMA insertion with propofol 2.0 mg/kg was 0.55 (0.44-0.66) μg/kg. Bradycardia occurred in four patients, and seven patients had an apneic episode.

CONCLUSION

The single dose of dexmedetomidine for successful LMA insertion to be feasible in 50% of patients was 0.55 μg/kg during anaesthesia induction with propofol 2 mg/kg.

Desflurane vs. sevoflurane as the main inhaled anaesthetic for spontaneous breathing via a laryngeal mask for varicose vein day surgery: a prospective randomized study

BACKGROUND

Sevoflurane has become widely used in day surgery; however, desflurane may be a valuable alternative even in this setting. This study compares emergence from anaesthesia for day surgery with spontaneous breathing using either desflurane or sevoflurane.

METHODS

This prospective, randomized, single-blinded study examined 70 ASA III patients undergoing elective ambulatory varicose vein surgery. Primary endpoint was emergence time (cessation of anaesthetic gas to communicating). Secondary endpoints included post-operative pain, nausea, time to discharge, and patient satisfaction. Patients were anaesthetized according to a standardized protocol including multimodal analgesia and antiemetic therapy and were randomized to receive sevoflurane or desflurane as the main anaesthetic while breathing spontaneously through a laryngeal mask airway. Fresh gas flow was oxygen in air 1 : 2 l/min.

RESULTS

Intra-operative anaesthesia was uneventful apart from airway irritation observed in 5/35 desflurane and 1/35 sevoflurane patients. Emergence was 25-40% faster in patients anaesthetized with desflurane. Pain and post-operative nausea and vomiting (PONV) were equally infrequent in both groups. Overall, patient satisfaction was high with no difference between the groups.

CONCLUSION

Desflurane is associated with a faster emergence with no differences during the post-operative course except a somewhat higher incidence of airway irritation.