A comparison of the effect of two anaesthetic techniques on surgical conditions during gynaecological laparoscopy.

In a prospective, randomised, controlled trial, we compared the effects of two anaesthetic techniques on surgical conditions during day-case, gynaecological laparoscopic procedures in 40 female patients. Patients were allocated randomly to two groups, either to breathe spontaneously through a laryngeal mask airway or to receive a neuromuscular-blocking agent (NMB) and have the lungs ventilated via a tracheal tube. We then measured the number of attempts of Verres' needle insertion, initial intra-abdominal pressure, time to reach a steady 15 mmHg (1.97 kPa) of intra-abdominal pressure, adequacy of the pneumoperitoneum, operative view and duration of operation. We found that the initial intra-abdominal pressure was higher and the operation time shorter in the laryngeal mask group. The adequacy of the pneumoperitoneum for trocar placement was better in the NMB group. We conclude that the anaesthetic technique of spontaneously breathing through a laryngeal mask airway reduces total operation time. However surgeons should be aware of the different abdominal pressure patterns produced by each anaesthetic technique, and anaesthetists must consider the implications of the anaesthetic technique on surgical safety.

Postoperative pain. Expectation and experience after coronary artery bypass grafting.

A study of 43 patients undergoing coronary artery bypass grafting was conducted in order to compare pre-operative expectation of pain severity and duration to actual postoperative experience. As judged by linear visual analogue scores, patients expected more pain than they experienced (p = 0.0359). For the majority of patients, pain duration was less than expected. Eighty-four per cent of patients reported that their pain was better or the same as expected. Ninety-five per cent of patients were satisfied or very satisfied with postoperative analgesia. The authors conclude that, although the standard of postoperative analgesia after coronary artery bypass grafting remains objectively poor (the median postoperative pain score was 4 on a 10 cm linear visual analogue pain score), patients are usually satisfied with their pain relief. The authors suggest that this may be related to patients' pre-operative overestimation of postoperative pain severity. The authors caution against giving patients unrealistic expectations of the quality of postoperative analgesia.

Ascorbic acid enhances iron-induced ferritin translation in human leukemia and hepatoma cells.

Ascorbate is an important cofactor in many cellular metabolic reactions and is intimately linked to iron homeostasis. Continuously cultured cells are ascorbate deficient due to the lability of the vitamin in solution and to the fact that daily supplementation of media with ascorbate is unusual. We found that ascorbate repletion alone did not alter ferritin synthesis. However, ascorbate-replete human hepatoma cells, Hep3B and HepG2, as well as K562 human leukemia cells achieved a substantially higher cellular ferritin content in response to a challenge with iron than did their ascorbate-deficient counterparts grown under standard culture conditions. Most of the elevation in ferritin content was due to an increase in de novo ferritin synthesis of greater than 50-fold, as shown by in vivo labeling with [35S]methionine and immunoprecipitation. RNA-blot analysis showed only minor changes in steady state levels of ferritin mRNA, suggesting that ascorbate enhances iron-induced ferritin synthesis primarily by post-transcriptional events. Transient gene expression experiments using chloramphenicol acetyltransferase reporter gene constructs showed that the ascorbate effect on ferritin translation is not mediated through the stem-loop near the translational start site that transduces ferritin synthesis in response to cytokines. The data suggest that ascorbate possibly modifies the action of the iron-responsive element on ferritin translation, although more precise structure-function studies are needed to clarify this issue. These data demonstrate a novel role of ascorbate as a signaling molecule in post-transcriptional gene regulation. The mechanism by which ascorbate modulates cellular iron metabolism is complex and requires additional detailed investigation.