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.

An evaluation of propofol toxicity on mouse oocytes and preimplantation embryos.

Mouse biological assays were used to investigate potential adverse effects of propofol on the oocyte's competence to fuse with spermatozoa and on the embryo's ability to develop to the blastocyst stage. Cumulus-enclosed metaphase II oocytes were exposed for 1 h to 0.01, 0.1, 0.4, 1 and 10 microg/ml propofol (Diprivan) and subjected to a sperm-oocyte fusion test based on the dye (Hoechst 33342) transfer technique. Oocytes exposed to 0.4, 1 and 10 microg/ml propofol showed a significant reduction in the rate of sperm fusion and underwent pronuclei formation at a rate similar to that of sperm fusion. In a second trial, mouse 1-cell and 2-cell embryos were exposed to varying propofol concentrations for 14h and then checked for subsequent development. Although adverse effects were not observed in 2-cell embryos, treatment of 1-cell embryos with propofol concentrations ranging from 0.01 to 10 microg/ml resulted in the inhibition of cleavage to blastocyst stage. We conclude that propofol can negatively influence fertilization in the mouse by impairing the oocyte's ability to fuse with spermatozoa, without interfering with the sperm-induced activation of the cell cycle. Moreover, we document the peculiar sensitivity to propofol of mouse 1-cell embryos as compared with 2-cell embryos.

The effect of early epidural block administration on the progression and outcome of labor.

This study was undertaken to prospectively evaluate the effect of early administration of epidural bupivacaine (0.25%) on the progression and outcome of labor in 60 nulliparous patients. Patients were randomly divided into two groups. In group 1 (30 patients, early administration), the epidural catheter was sited and the first epidural injection of 0.25% bupivacaine administered at a cervical dilatation of <4 cm; group 2 (30 patients, late administration) received the epidural catheter and first epidural injection of 0.25% bupivacaine at a cervical dilatation of >or=4 cm. The progression and outcome of labor were compared between the two groups. There were no statistically significant differences between the two groups in rate of cervical dilatation, duration of the second stage, numbers of instrumental deliveries or cesarean sections or Apgar scores at 1 and 5 min. We conclude that there is no need to restrict epidural top-ups until cervical dilatation of 4 cm, when active management of labor is advocated.

Effect of second-stage 0.25% epidural bupivacaine on the outcome of labor.

OBJECTIVE: To evaluate the effect of second-stage epidural bupivacaine on the outcome of labor. METHODS: Two groups of 35 patients each were randomly allocated to receive continuous epidural bupivacaine throughout labor (group 1) or until an 8-cm dilatation of the cervix (group 2). RESULTS: There was no significant difference between the 2 groups in the rates of instrument deliveries and in their Apgar scores. CONCLUSIONS: The administration of continuous epidural bupivacaine (0.25%) throughout labor and delivery does not seem to affect the outcome of labor.