To the Editor: I read with great interest the recent article of Aubin et al. describing the use of high frequency ventilation during the intraoperative care of an infant with diffuse bullous lesions. 1 The authors should be congratulated for the care they provided this child. They demonstrated the overlap of the intensive care unit and the operating room as well as the need for anesthesiolo-gists to maintain a working knowledge of new technology in both settings. In their discussion, the authors rightly state that P ET CO 2 cannot be measured during high frequency ventilation. 2 Although the authors state that arterial blood gases must be sampled to frequently, I would like to suggest another alternative. We published our experience with transcutaneous CO 2 monitoring during respiratory failure and following cardiothoracic surgery in infants and children. 3,4 In addition to the obvious problems with P ET CO 2 monitoring during high frequency ventilation, other factors including ventilation-perfusion inequalities, sampling errors, and patient positioning can interfere with its accuracy. In infants and children with respiratory failure, we found that transcutaneous monitoring provided a better estimation of PaCO 2. 3 Despite our success with this technology, its use outside the neonatal period and especially in the operating room remains limited. with recent advancements in the technology, transcutaneous CO 2 has become a simple, non-invasive way of estimating PaCO 2. We are currently investigating the applications of this technology in the adult population.

Purpose: To document the range and the most common strategies for the management of the parturient with inadvertent dural puncture (DP) dudng labour epidural analgesia. Methods: A confidential survey form was mailed to 46 academic units in Canada and USA. The responses were compiled into Canadian, US and joint North American databases. Results: Thirty-six centres (78%) responded, representing 137,250 annual deliveries. The reported incidence of DP was 0.04-6%. The most common initial response to DP was re-siting the catheter at another level. Most centres made little change in routine practice regarding epidural top-ups and infusion rates after DP. Unrestricted mobilisation was advocated by 86% of centres following delivery; enhanced oral hydration was encouraged by 6 I%. Prophylactic epidural blood patch (PEBP) was recommended by 37% of centres, with twice as many US as Canadian centres doing so. In the presence of PDPH, EBP was offered most commonly at or within 24 hr of diagnosis. Complications were common after EBP: 86% of centres reporLed patch failures; 44% reported persistent headache after 22 EBP. Despite this, centres remained optimistic about EBP success, quoting cure rates >90% in 58% of centres. Conclusion: There is little difference between the practices reported by Canadian or US centres. The expressed optimism regarding the efficacy of EBP is not supported by the evidence available and may be unwarranted. More research is neec~ed to define the issue better.Objectif : Documenter r&endue du probl6me et les strategies les plus utilis&s pour traiter la parturiente avec ponccion accidentelle de la dure-m~re (PDM) durant ranalg6sie pour le travail. M&hodes : Une enqu&e con~dentielle a 6t6 adress6e par la poste ~. 46 d6partements acad6miques au Canada et aux ~tats-Unis. Les r6ponses ont &6 complines darts les bases de donn&s canadienne, am6ricaine et nordam&icaine conjointe. I~sultats : Trente-six centres (78%) ont r6pondu, ce qui repr&entait 137,250 accouchements. I'incidence rapport~e de PDM &ait de 0,04~6%. La r~action initiale la plus fr6quente ~ une PDM &air de reprendre la technique ~ un autre niveau. La plupart des centres ne modifiaient pas leur routine concemant les vitesse d'infusion et les bolus apr6s PDN. La mobilisation ~ volont~ ~ la suite de t'accouchement &air pr6n6e par 86% des centres; 61% encourageaient une hydratation orale accrue. Le pansement de sang 6pidural (PSE) prophylactique ~tait recommand6 par 37% des centres, et ce deux fois plus souvent aux USA qu'au Canada. En presence de c~phal6e post-ponction de la dure-m&e (CPPDM), le PSE &ait offert le plus souvent au moment du diagnostic ou dans les 24 heures subs6quentes. Les complications sont fr~quentes apr& PSE : 86% des centres rapportent des 6checs; 44% rapportent des c~phal~es persistantes apr~s 2 2PSE. Malgr6 ceci, les centres demeurent optimistes quant au succ& du PSE, 58% des centres rapportent des taux de succ& de >90%. Conclusion : II y a peu de diff&ence entre la pratique au Canada et aux I~tats-Unis. I'optimisme d6montr6...

FRCPCPurpose: To compare both the efficacy and cost of nalbuphine and diphenhydramine in the treatment of intrathecal morphine-induced pruritus following Caesarean section. Methods: Eighty patients, undergoing elective Caesarean section under spinal anaesthesia, were randomized, in a prospective, double-blind trial, to receive either nalbuphine (Group NAL) or diphenhydramine (Group DIP) for the treatment of SAB morphine-induced pruritus. All patients received an intrathecal injection of 1 0-12 mg hyperbaric bupivacaine 0.75% and 200 ~tg preservative free morphine. Postoperative pruritus was assessed, using a visual analogue scale (VAS), for 24 hr. Pruritus treatment was administered upon patient request and by a nurse blinded to the treatment given. Patients who failed to respond to three doses of the study drug were deemed treatment failures. Patient satisfaction was assessed with a questionnaire given 24 to 48 hr after surgery. Direct drug costs were calculated based on the pharmacy provision costs as of April 1996. Results: Eighty patients were enrolled and 45 requested treatment for pruritus. Patients treated with NAL (n = 24) were more likely to achieve a VAS score of zero with treatment (83% vs 43%, P < 0.01), had a higher AVAS following treatment (4 + 2 vs 2 ___ 2, P < 0.003), and experienced fewer treatment failures (4% vs 29%, P < 0.04), than those treated with DIP (n = 21 ). Group NAL patients were also more likely to rate their pruritus treatment as being good to excellent (96% vs 57%, P < 0.004). Direct drug costs were higher for NAL than for DIP ($6.4 +_ 3. I vs $1.7 _+ 0.7, respectively, P < 0.0001). Conclusion: Nalbuphine is more effective than diphenhydramine in relieving pruritus caused by intrathecal morphine and the cost differences are small.Objectif : Comparer I'efficacit~ et le cofit de la nalbuphine avec ceux de la diphenhydramine administr6e apr& la c&arienne comme traitement du prurit provoqu~ par la morphine sous-arachndfdienne. M&hodes : Dans cette 6tude prospective en double aveugle, 80 parturientes op6r6es pour une c&arienne non urgente sous rachianesth&ie ont ~t~ r6parties au hasard pour recevoir comme traitement du prurit provoqu6 par la morphine soit de la nalbuphine (groupe NAL), soit de la diphenhydramine (groupe DIP). Toutes les patientes ont re~u une injection sous-arachndidienne de 10-12 mg de bupivac~'ne 0,75% hyperbare avec 200/~g de morphine sans pr&ervatif. Une &helle visuelle analogique (EVA) a servi ~ 6valuer I'intensit~ du prurit postop&atoire pendant 24 h. Le traitement antiprurigineux a &6 administr6 ~ la demande de la patiente et par une inflrmi&e ignorant la nature du traitement. On consid&ait le traitement comme un &hec en I'absence de r6ponse ~trois doses de la drogue &udi&. La satisfaction de la patiente &ait ~valu& avec un questionnaire administr~ 24 ~ 48 h apr& la chirurgie. Les coots d'approvisionnement de la pharmacie en avril 1996 repr~sentaient les coots directs des produits utilis&. R~sttltats : Quarante-cinq des 80 participantes ~ I'&ude ont demand~ un t...