The cardiovascular response to insertion of the intubating laryngeal mask airway

Sixty-one patients received a standardised anaesthetic and were randomly assigned to three groups: tracheal intubation via direct laryngoscopy, tracheal intubation via an intubating laryngeal mask airway with immediate removal of the device, and tracheal intubation via an intubating laryngeal mask airway with delayed removal. The cardiovascular response to intubation was of a similar magnitude in all groups, although delayed removal of the intubating laryngeal mask airway was associated with a second pressor response. Norepinephrine changed significantly over time following direct laryngoscopy and following immediate removal of the intubating laryngeal mask airway, but not after delayed removal. The findings of this study do not support using the intubating laryngeal mask instead of direct laryngoscopy purely to decrease the response to intubation.

Fibreoptic views through the laryngeal mask and the intubating laryngeal mask

BACKGROUND AND OBJECTIVE

The intubating laryngeal mask (intubating laryngeal mask airway) was designed to facilitate blind intubation. Its value as an adjunct to fibreoptic laryngoscopy has not been evaluated. This study compares the intubating laryngeal mask airway with the standard laryngeal mask airway as conduits for fibreoptic laryngoscopy.

METHODS

The fibreoptic view of the laryngeal inlet was graded via both devices in 60 anaesthetized patients. The fibreoptic view through the intubating laryngeal mask airway was assessed after the central epiglottic elevator bar had been lifted out of the field of vision by an 8-mm Euromedical tracheal tube, which was inserted to a depth of 18 cm. The fibreoptic view from the aperture bars of the laryngeal mask was recorded.

RESULTS

The vocal cords were viewed less frequently through the intubating laryngeal mask airway (52%) than through the laryngeal mask airway (92%) [difference = 40% (95% CI = 26% to 54%), P < 0.0001].

CONCLUSION

The view of the laryngeal inlet is better through the laryngeal mask airway than through a tracheal tube inserted to 18 cm in the intubating laryngeal mask.

A comparison of the intubating and standard laryngeal mask airways for airway management by inexperienced personnel

Twenty-four inexperienced participants were timed inserting the intubating laryngeal mask airway and the laryngeal mask airway in 75 anaesthetised subjects. Adequacy of ventilation was assessed on a three-point scale. The pressure at which a leak first developed around the device's cuff was also measured. There was no significant difference in insertion time or the likelihood of achieving adequate ventilation between devices. However, the intubating laryngeal mask airway was better at providing adequate ventilation without audible leak (58/75 (77%) vs. 42/75 (56%); p = 0.009). The median (range [IQR]) pressure at which an audible leak developed was higher for the intubating laryngeal mask airway, 34.5 (14-40 [29-40]) cmH2O, than for the laryngeal mask airway, 27.5 (14-40 [22-33]) cmH2O (p < 0.001). The intubating laryngeal mask airway is worthy of further consideration as a tool for emergency airway management for inexperienced personnel.

What is the relationship between paresthesia and nerve stimulation for axillary brachial plexus block?

BACKGROUND AND OBJECTIVES

To quantify the motor threshold current of a needle following elicitation of paresthesia during axillary brachial plexus block (ABPB).

METHODS

This is a prospective, observational study of ABPB in 72 patients. Having elicited paresthesia, the minimum current required to produce a motor response was noted. The development and success of the block were subsequently followed.

RESULTS

Nineteen blocks were excluded (18 because of arterial puncture and 1 blocked needle). Of the remaining 53 blocks, 41 (77%) produced a motor response at 0.5 mA or less. The median current was 0.17 mA (range, 0.03 to 3.3 mA). The site of initial paresthesia and subsequent motor response were related in 43 (81%) of cases.

CONCLUSIONS

A needle position causing paresthesia produced a motor response at 0.5 mA or less in 77% of cases studied. This current may, therefore, be a reasonable threshold to aim for when performing an ABPB.

Comparison of laryngeal mask and intubating laryngeal mask insertion by the naïve intubator

Seventy-five inexperienced participants were timed inserting the laryngeal mask airway (LMA) and the intubating laryngeal mask (ILM) in one of five cadavers. Adequacy of ventilation was assessed on a three-point scale depending on chest expansion and air leak. Participants were also asked to intubate the trachea via the ILM. The ILM was inserted faster than the LMA (P < 0.05) with a greater proportion achieving adequate ventilation after their first attempt (P < 0.05). Tracheal intubation via the ILM was completed successfully by 67% (52 of 75) of participants. In a questionnaire, participants stated that the ILM was easier to use and the preferred device in an emergency. The results suggest that inexperienced practitioners should use the ILM rather than the LMA for emergency ventilation.

A prospective audit of wound infection rates after caesarean section in five West Yorkshire hospitals

A three month prospective audit of wound infection following emergency and elective caesarean section was carried out in five West Yorkshire hospitals. Among 4076 women undergoing delivery in the five obstetric departments, the caesarean rate was 15.4%. The overall infection rate was 45/628 (7.2%) with a range of 2.5-17.2% between the five centres. The infection rate was 14/226 (6.2%) when antibiotics were used compared with 31/402 (7.7%) without antibiotics. The use of prophylactic antibiotics made no significant difference to the infection rate, which did not correlate with duration of labour or of ruptured membranes. The number of vaginal examinations correlated with the infection rate. In conclusion, the caesarean section rate observed was higher than that estimated for the UK as a whole, but was distorted by one centre with a high rate. For the other four hospitals the caesarean rate was unexceptional. The ratio of emergency to elective operations was comparable with recently reported values in the UK and the wound infection rate was within the widely varying limits found in previous studies. In view of the relatively low infection rate recorded without antibiotics, in the interests of cost effectiveness, prophylaxis may be limited in future to selected women at high risk. Because this was an audit rather than a randomized study we cannot exclude that this is already happening on an empirical basis.

Reducing bruising after venepuncture

Bruising after venepuncture is undesirable. To verify an apparent increase in bruising after introducing a new venepuncture system in a small district general hospital and to improve the venepuncture service two prospective audits of the incidence and severity of bruising after venepuncture were performed in two groups of 100 consecutive inpatients undergoing venepuncture by phlebotomists. In the first audit bruising was detected in 45 patients, of whom 34(76%) had bruises > 100 mm2 in area. After modification of the technique, whereby the phlebotomists ensured that haemostasis had been attained before leaving the patient, bruising was significantly reduced, occurring in 25 patients only 9 of whom (36%) had bruises > 100mm2 in area (both p < 0.01) in the second audit. Monitoring of standards and simple modification of technique resulted in significant reduction in incidence and severity of bruising, improving the quality of the venepuncture service.

Cervical cancer screening and registration--are they working?

STUDY OBJECTIVE

The aim of the study was to investigate the accuracy of one year's cervical cancer registrations and to review these women's medical records.

DESIGN

The study was a survey of medical records of women registered as having a malignancy of cervix or uterus in 1985.

SETTING

Cases were drawn solely from the county of Leicestershire, having been registered by the Trent Cancer Registration Bureau.

PATIENTS

The study group comprised all 82 women registered as having a malignancy of cervix or uterus (part unspecified) during the study period. In one case the medical records could not be obtained, so 81 were reviewed.

MEASUREMENTS AND RESULTS

Medical records were reviewed; demographic, clinical and tumour characteristics, and screening experience were noted. Errors of registration of invasive cancer resulted in a 22% overestimate: only 54 of 66 cases registered actually had this cancer. Cases over 40 years of age (n = 37) were compared to those under 40 (n = 17). Thirty two women (59%), predominantly in the older age group, had never had a cervical smear. Forty four women (81%) presented with symptoms rather than as a result of screening. There was no difference in the stage of the disease at presentation between the two age groups but eight of nine women under 35 years had poorly differentiated tumours. At 2 year follow up, 12 (71%) of the younger women were alive and asymptomatic, one had a recurrence and four were dead. The corresponding figures for the older women were 18 (50%), 5 (14%) and 13 (36%). Eight screened women had only had normal smears reported in the 5 years preceding the cancer diagnosis. Seven of these were under 45 years old and four had late stage disease.

CONCLUSIONS

It will be impossible to assess the impact of newly implemented computerised call and recall systems for cervical cytology screening unless a more reliable data base can be created.