On the formation of current ripples.

For grain sizes finer than coarse sand, the first flow-transverse bedforms to develop are current ripples. Although numerous studies have analysed different aspects of bedform morphodynamics, to date no comprehensive physical explanation for the formation of ripples has been given. We offer such an explanation based on a virtual boundary layer concept, and present a model predicting ripple height on the basis of grain size, current velocity and water depth. The model contradicts the conventional view of current ripples as bedforms not scaling with flow depth. Furthermore, it confirms the dependence of ripple dimensions on grain size, and their relative insensitivity to flow strength.

Is day surgery safe? A Danish multicentre study of morbidity after 57,709 day surgery procedures.

BACKGROUND: Day surgery is expanding in several countries, and it is important to collect information about quality. The aim of this study was to assess morbidity and unanticipated hospital visits 0-30 days post-operatively in a large cohort. METHODS: We prospectively recorded data from 57,709 day surgery procedures performed in eight day surgery centres over a 3-year period. We cross-checked with the National Patient Registry to identify complications 0-30 days post-operatively, and registrations from The Danish Register of Cause of Death were requested. We retrieved the records of 1174 patients to assign a relation between secondary contact and day surgery. RESULTS: The overall rate of return hospital visits was 1.21% [95% confidence interval (CI): 1.12-1.30%] caused by a wide range of diagnoses. No deaths were definitely related to day surgery. The return hospital visits were due to haemorrhage/haematoma 0.50% (95% CI: 0.44-0.56%), infection 0.44% (95% CI: 0.38-0 49%) and thromboembolic events 0.03%. Major morbidity was rare. The surgical procedures with the highest rate of complication were tonsillectomies 11.4%, surgically induced abortions 3.13% and inguinal hernia repairs 1.23%. CONCLUSION: This large-scale Danish national study confirmed that day surgery is associated with a very low rate of return hospital visits. Despite the rapid expansion of day surgery, safety has been maintained, major morbidity being very rare, and no deaths being definitely related to day surgery.

Comparison between local anaesthesia with remifentanil and total intravenous anaesthesia for operative hysteroscopic procedures in day surgery.

BACKGROUND: This study aimed at comparing total i.v. anaesthesia (TIVA) with monitored anaesthesia care (MAC) during day-surgery operative hysteroscopy regarding: operation time, time to mobilization and discharge, and patient satisfaction. METHODS: Ninety-one healthy women were randomized to MAC with paracervical local anaesthesia and remifentanil or to TIVA with propofol and remifentanil. Time from arrival to leaving the operating theatre, time from arrival in the recovery room to mobilization and discharge readiness, and patient satisfaction with MAC and TIVA were observed. RESULTS: Time from arrival to leaving the operating theatre showed no significant difference between groups (P=0.6). The time to mobilization {MAC: 53 min [inter-quartile range (IQR) 40-83], TIVA: 69 min (IQR 52-96) (P=0.017)} and the total time from arrival to discharge readiness [MAC: 118 min (IQR 95-139), TIVA: 138 (IQR 120-158) (P=0.0009)] were significantly reduced for patients in the MAC group. More patients in the MAC group 45 (91.8%) than in the TIVA group 24 (64.9%) responded positively to the question: would you like to receive the same kind of anaesthesia for a similar procedure in the future? (P=0.003). CONCLUSIONS: Paracervical local anaesthesia combined with remifentanil is suitable for operative hysteroscopy in day surgery.

Return hospital visits and morbidity within 60 days after day surgery: a retrospective study of 18,736 day surgical procedures.

BACKGROUND: As day surgery includes more extensive procedures focus should be put on late outcome. The frequency of day surgery-related return visits and the associated morbidity were examined to identify suitable indicators of quality. METHODS: From two centres, 16,048 patients underwent 18,736 day surgery operations including 4,829 surgical abortions. Patients were retrospectively analysed for contacts to Danish hospitals within 60 post-operative days and the associated morbidity and mortality. Data were obtained from the Danish National Patient Registry and the National Causes of Death Registry. Patient records were studied to validate contacts as being definite, likely, possible or not related. RESULTS: Altogether 113 patients (not including the surgical abortions) were readmitted to hospitals with 117 complications definitely or likely related to day surgery. The most common complications were haematomas or haemorrhage (0.40%) and infections (0.29%). Morbidity after the two most common procedures, hernia repair and knee arthroscopy, was observed in 1:39 patients and 1:220 patients, respectively. More serious complications included four patients with septic arthritis of the knee and six patients with venous thromboembolism. After surgical abortion, pelvic inflammation and bleeding were observed in 3.1% and 2.2%, respectively, with centre differences. Altogether no myocardial infarctions, central nervous system deficits, pneumonias or deaths were recorded that could definitely or likely be related to day surgery. CONCLUSION: Day surgery in Denmark is a safe practice. Readmission rates, haematomas and wound infections are likely future indicators of outcome quality after day surgery.

[Brachial plexus blockade via the interscalene port--for regional anesthesia/analgesia of upper extremities; use, application and risks]. / Plexus brachialis-blokade anlagt via skalenerporten--til regional anaestesi/analgesi af overekstremiteten; anvendelse, anloeggelse og risici.

The interscalene technique for brachial plexus anaesthesia is described. The method is suitable for anaesthesia of the upper extremity, especially when anaesthesia of the proximal part of the arm and the shoulder region is desired. The technique is also useful in paediatric cases. Side effects are few, but the risk of paralysing of the diaphragm makes this method inappropriate for patients with severe respiratory disease.

Preoperative infiltration of the surgical area enhances postoperative analgesia of a combined low-dose epidural bupivacaine and morphine regimen after upper abdominal surgery.

In a randomized, blinded trial we assessed the value of adding preoperative infiltration of the surgical area with bupivacaine to a low dose epidural regimen for postoperative pain treatment. Forty-nine patients scheduled for major upper abdominal surgery during combined thoracic epidural (bupivacaine + morphine) and general anaesthesia were studied. Postoperative analgesia was epidural bupivacaine 10 mg/hr-1 + morphine 0.2 mg/hr-1 for 72 h. The patients randomly received preoperative infiltration of the surgical area with bupivacaine 0.25%, 40 ml (group I); or no infiltration (group II). Pain was evaluated at rest, during cough and during mobilization six and eight h after start of surgery, and at 8 a.m. and 4 p.m. on the following days until 72 h after start of surgery. The sensory level of analgesia was evaluated by pin prick. We found no difference between the two groups during rest and cough. However, during mobilization group I had lower pain scores compared to group II (P < 0.05). There was a significant reduction in the need for supplemental intramuscular morphine in the treatment group compared to the control group (P < 0.05). Thus an enhanced analgesic effect was demonstrated by adding preoperative infiltration of the surgical area with local anaesthetic to a low dose epidural bupivacaine/morphine regimen after upper abdominal surgery.

Foreign body perforation of the gastrointestinal tract with formation of liver abscess.

A unique case of foreign body perforation of the stomach directly into the liver with formation of a liver abscess is presented. The literature concerning foreign body perforation of the gastrointestinal tract complicated by liver abscess is reviewed.