Laryngeal mask in prone position: pure exhibitionism or a valid technique

AIM

The laryngeal mask airway (LMA) is used worldwide during general anesthesia with controlled or spontaneous breathing. Normally its use is limited to patients undergoing surgery in the supine but not the prone position.

METHODS

A prospective study of 50 consecutive ASA 1 and 2 patients who underwent ambulatory surgery in the prone position. In the first 25 patients anesthesia was induced in the supine position on a transport trolley after which the patients were turned face down following tracheal intubation. The next 25 patients were asked to lie comfortably in the prone position before receiving anesthesia. Induction and insertion of LMA were performed when they were already prone.

RESULTS

There were neither complications nor airway loss when LMA was used in the prone position. The induction-incision time was 23.6+/-3.6 min (range 21-37) in Group 1 and 7+/-2.44 min (range 5-15) in Group 2 (P<0.0001) and the manpower required for positioning (the number of medical and paramedical personnel required to place the patient prone) was considerable reduced in Group 2 (LMA) compared to Group 1 (1.0 versus 3.12+/-0.6 (range 2-4; P<0.0001). Group 2 showed also, significantly more favorable hemodynamic parameters.

CONCLUSION

To start anesthesia with patients already prone shortens the induction-incision time, reduces the manpower involved in the positioning process and causes fewer hemodynamic changes than the standard technique of induction and intubation in the supine position followed by turning the patient facedown.

Laryngeal mask airway and the Robinow syndrome

The Robinow syndrome is an extremely rare congenital syndrome that causes facial malformations, as well as genital, cardiac and skeletal abnormalities. Patients with this syndrome undergo several operations during their life. Because of the facial abnormalities they carry a potential risk for difficult intubation. We describe the case of a boy who underwent several operations with documented difficult intubation. The laryngeal mask airway provided a good solution for airway control and afforded adequate ventilation under both controlled mechanical ventilation and spontaneous breathing.

Insertion of the endotracheal tube, laryngeal mask airway and oesophageal-tracheal Combitube®. A 6-month comparative prospective study of acquisition and retention skills by medical students

OBJECTIVE

To assess the ability of medical students to learn and retain skills of airway manipulation for insertion of the endotracheal tube, the laryngeal mask airway (Laryngeal Mask Company, Henley-on-Thames, UK) and the oesophageal-tracheal Combitube (Kendall-Sheridan Catheter Corp., Argyle, NY, USA).

METHODS

A 6-month prospective study was conducted among fifth-year medical students attending a 3-week clerkship in the Division of Anesthesiology and Critical Care Medicine in the Soroka Medical Center. All the students viewed a demonstration of insertion technique for the endotracheal tube, the laryngeal mask airway and the Combitube, followed by formal teaching in a mannikin. At the end of the program, the insertion skills were demonstrated in the mannikin, the success rate on the first attempt was registered and the students were requested to assess (by questionnaire) their ability to execute airway manipulation (phase 1). Six months later, the students were requested to repeat the insertion technique, and a similar re-evaluation applied (phase 2).

RESULTS

The success rate, during the first phase, at first attempts was 100% for the laryngeal mask airway and the Combitube, compared to 57.4% for the endotracheal tube (P < 0.02), and 92.6%, 96.2% and 62.9% (P < 0.02) respectively for the second phase of the study.

CONCLUSION

Learning and retention skills of medical students, in a mannikin, are more accentuated with the laryngeal mask airway and the Combitube than seen with an endotracheal tube.

The anaesthetic management of patients with congenital insensitivity to pain with anhidrosis

BACKGROUND

Congenital insensitivity to pain with anhidrosis (CIPA, or hereditary sensory and autonomic neuropathy type IV) is a rare, autosomal recessive disease, related to a mutation in the TrkA gene, characterized by inability to sweat, insensitivity to pain and recurrent episodes of hyperpyrexia. There are two Bedouin tribes in Israel with different mutations of the TrkA gene: one in the southern region and the other in the northern region. The Soroka University Medical Center is the referral centre for the entire southern region of Israel. One in 4500 anaesthesia cases involves a patient with CIPA.

METHODS

We reviewed 40 anaesthesia records of 20 patients with CIPA for anaesthetic technique and incidence of side-effects.

RESULTS

Sixteen patients developed complications in the immediate perioperative period: mild hypothermia in one patient and cardiovascular events in 15 others with one case of cardiac arrest. These complications were unrelated to the anaesthetic drug administered. There were no events of hyperthermia or postoperative nausea.

CONCLUSIONS

Cardiovascular complications following anaesthesia are common in patients with the southern Israel variant of CIPA. Hyperthermia, previously recognized as a major concern in patients with congenital insensitivity to pain with anhydrous, was not seen in our patients. We conclude that cardiovascular involvement is frequently encountered in CIPA patients following anaesthesia and is the major concern in their anaesthetic management.

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.

Vocal cord paralysis as a consequence of peritonsillar infiltration with bupivacaine

Reduction of postoperative pain is an important goal in the perioperative management of tonsillectomy patients. This is particularly the case for children, who often exhibit resistance to intramuscular or rectal administration of drugs. Peritonsillar bupivacaine infiltration, a relatively safe method of pain control, is in some centers frequently used by otolaryngologists for pain relief. We present the case of a 5-year-old girl who developed bilateral vocal cord paralysis following preoperative peritonsillar bupivacaine infiltration. After an uneventful tonsillectomy and extubation, stridor and respiratory distress developed. Bilateral vocal cord paralysis was seen on laryngoscopy. The patient was reintubated and five hours later was successfully extubated without further sequelae. Anesthesiologists and surgeons should be aware of this uncommon complication than can occur with the use of peritonsillar bupivacaine infiltration for pain control in tonsil surgery.

Commercial propofol solutions: is the more expensive also the more effective?

STUDY OBJECTIVE

To compare the efficacy and safety of four commercial propofol solutions marketed in Israel.

DESIGN

Prospective, randomized, double-blind study.

SETTING

University-affiliated medical center.

PATIENTS

120 ASA physical status I and II nullipara patients undergoing dilatation and curettage for interrupted pregnancy.

INTERVENTIONS

Patients were randomized into four groups of 30 patients each. Group 1 was anesthetized with Diprivan (AstraZeneca, UK), group 2 with Recofol (Leiras Oy, Finland), group 3 with Propofol (Abbott), and group 4 with Diprofol (Taro, Israel).

MEASUREMENTS AND MAIN RESULTS

The four study groups were similar in mean age and weight. There were no statistically significant differences in the administered doses, quality of anesthesia, recovery time, or adverse effects among the four groups.

CONCLUSIONS

Diprivan, Recofol, Diprofol, and Propofol Abbott are equally effective as anesthesia induction drugs for dilation and curettage, with a similar incidence of adverse effects. Because cost limitations have become a significant factor in medical care, the choice of drug in this group should be based solely on cost considerations.

Respiratory arrest and convulsions after peribulbar anesthesia

We present a case in which a rare and serious complication with respiratory arrest and convulsions occurred after peribulbar anesthesia for cataract surgery. To our knowledge, respiratory arrest has been described as a complication only of retrobulbar, not peribulbar, anesthesia. Anesthesiologists trained in airway maintenance and ventilatory support should be available for immediate help when a peribulbar block is performed.

Anaesthetic interaction between thiopentone and ketamine

The anaesthetic effect of thiopentone, ketamine and their combinations were studied in 150 patients of ASA Grades I and II. The ability to open eyes on command and purposeful motor response to noxious pressure on the trapezius muscle were used as endpoints of anaesthesia. Dose-response curves for thiopentone, ketamine and their combinations were determined with a probit procedure and compared with isobolographic analysis. The interaction between thiopentone and ketamine was found to be additive for both endpoints of anaesthesia.