Persistent Depression of Contractility and Vasodilation with Propofol but Not with Sevoflurane or Desflurane in Rabbits

Background: Propofol, sevoflurane, and desflurane may cause hemodynamic compromise during anesthesia and critical care management. The aim of the study was to compare these anesthetics during increased dose and recovery to maintenance level.

Methods: Anesthetized, open-chest New Zealand White rabbits were used to acquire dose-response curves with sevoflurane, desflurane, and propofol, followed by reduction to baseline infusion. Simultaneous high-fidelity left ventricular pressure and volume data were acquired during caval occlusion with a dual-field conductance catheter inserted via an apical stab. The preload recruitable stroke work and the end-diastolic pressure-volume relationship were used as the primary measures of contractility and diastolic function.

Results: The time-matched controls were stable over time. Propofol and desflurane but not sevoflurane caused dose-dependent reductions in myocardial contractility, although sevoflurane reduced contractility more at 1 minimal alveolar concentration. All anesthetics reduced mean arterial pressure, and significant recovery occurred for sevoflurane and desflurane but not for propofol. The end-diastolic pressure-volume relationship was increased by sevoflurane. Ejection fraction decreased with sevoflurane only. All anesthetics caused dose-dependent vasodilation, with recovery for desflurane and sevoflurane but not propofol. Heart rate was decreased with propofol without significant recovery. Propofol plasma concentrations remained elevated after dose return to baseline infusion rate, suggestive of distribution compartment saturation.     

Use of stand-up magnetic resonance imaging for evaluation of a cervicothoracic injury in a patient with ankylosing spondylitis

BACKGROUND CONTEXT: Injuries at the cervicothoracic junction are common in patients with ankylosing spondylitis. These injuries present challenges for both initial and follow-up imagings. PURPOSE: To describe a case of a patient with ankylosing spondylitis who was treated with laminectomy and a cervicothoracic orthosis for a spinal epidural hematoma after a nondisplaced fracture at the cervicothoracic junction and to discuss the merits of stand-up magnetic resonance imaging (MRI) for follow-up evaluation of this type of injury. STUDY DESIGN/SETTING: Case report. METHODS: Clinical data of a patient with ankylosing spondylitis who sustained a nondisplaced C7 fracture are presented, followed by a detailed review of the literature concerning imaging techniques available for the evaluation of cervical spine trauma in this patient population. RESULTS: The patient was treated with emergent laminectomy and evacuation of the epidural hematoma, followed by definitive management in a cervicothoracic orthosis secondary to medical comorbidities. The patient was then successfully followed postoperatively with stand-up MRI because conventional imaging techniques could not adequately image the injury level in an upright position. CONCLUSIONS: Cervicothoracic injuries are common in patients with ankylosing spondylitis and may be difficult to follow with conventional imaging techniques. Stand-up MRI is a relatively new modality that may offer significant advantages over conventional imaging because of the ability to evaluate the cervicothoracic junction in a more functional position and the lack of a confining space such as that found in standard MRI units.     

Transient urethral obstruction predisposes to ascending pyelonephritis and tubulo-interstitial disease: studies in rats

Chronic tubulo-interstitial disease, an important cause of end-stage renal disease, often results from the combined effects of a disturbed urinary outflow tract and urinary tract infection. Acute unilateral ureteral obstruction in rats rapidly induces foci of medullary necrosis, confined to the region of the papilla and fornices. This injury may provide a nidus for bacterial invasion and may invoke reactive and regenerative changes, ultimately leading to chronic pyelonephritis and tubulo-interstitial nephropathy. To explore this possibility, adult rats underwent renal morphological evaluation 2–7 days following transient 24-h unilateral ureteral obstruction. In some experiments the bladder was inoculated with bacteria (10⁸–10⁹ cfu/ml Escherichia coli in 0.5 ml) after release of ureteral obstruction, with subsequent cultures obtained from the pelvis of both kidneys and from the urinary bladder. Morphologic evaluation of perfusion-fixed kidneys, 2–7 days after the release of 24-h ureteral obstruction disclosed papillary necrosis, urothelial proliferation, marked inner-stripe interstitial expansion, and fibrosis and proximal tubular (S₃) dilatation. The lateral (perihilar region) was predominantly affected, with lesions spreading from the fornices. There was some progression of interstitial fibrosis during the postobstructive time course or following more prolonged ureteral obstruction. By contrast, infection hardly contributed to the tubulointerstitial changes. In rats subjected to infection, cultures were positive in all 15 postobstructive kidneys, as opposed to five contralateral kidneys (P < 0.0001). Viable counts from the postobstructive kidney were also higher than those from the contralateral side (79,000 ± 12,000 vs 2900 ± 1600 cfu/ml, mean ± SEM, P < 0.0001), and were comparable to those obtained from the bladder (77,000 ± 13,000 cfu/ml). We conclude that transient ureteral obstruction predisposes to ascending pyelonephritis and to tubulointerstitial disease. This vulnerability may relate to altered urodynamics and medullary tissue destruction. Received: 28 December 1999 / Accepted: 28 September 2000     

Pulmonary resection for metastases from colorectal cancer

Aim: The prognosis of patients with disseminated colorectal carcinoma is poor except for those with single organ pulmonary or hepatic metastases. The objective of the present study was to evaluate the result of pulmonary metastasectomy for colorectal secondary and to identify the prognostic factors. Methods: This was a retrospective study of 80 patients who had pulmonary metastasectomy for pulmonary secondary from colorectal carcinoma in Queen Elizabeth Hospital, Hong Kong. Results: The overall 5‐year and 10‐year survival rates of the entire cohort were 42.5% and 35.5%, respectively. High premetastasectomy carcinoembryonic antigen (> 20 μg/dL), short disease‐free interval (< 12 months) and incomplete resection were the independent prognostic factors. Neither the characteristics of the primary colorectal tumour nor the number of metastatic nodules had a significant contribution to the long‐term survival. Six patients underwent second pulmonary metastasectomy and three were still free from tumour recurrence after the second operation. Conclusion: Patients with pulmonary metastases from colorectal carcinoma would benefit from pulmonary metastasectomy. High premetastasectomy carcinoembryonic antigen and short disease‐free interval were negative predictive factors for survival. Long‐term follow‐up study is required, as recurrence can occur more than 5 years after pulmonary metastasectomy. Also, whether the survival benefit is due to surgical treatment effect or lead‐time bias remains undecided.     

Pediatric robotic surgery: lessons from a clinical experience

PURPOSE: Robotic surgery may improve minimally invasive surgery at high magnification by tremor filtration, motion-scaling, and improved dexterity with the provision of a wrist at the end of the robotic instrument. MATERIALS AND METHODS: We chose the Zeus Microwrist robotic surgical system as more applicable to small children than the competing da Vinci surgical system. We attempted 57 surgical procedures and completed 54. RESULTS: Completed procedures included Nissen fundoplication (n = 25), cholecystectomy (n = 18), Heller myotomy (n = 2), splenectomy (n = 2), Morgagni hernia repair (n = 2), and single cases of complex pyloroplasty in the chest, bowel resection, left Bochdalek congenital diaphragmatic hernia repair, esophageal atresia and tracheoesophageal fistula repair, and choledochal cyst excision. There were no complications related to the use of the robot. The mean time for the surgeon at the console using the robot was 117 +/- 39 minutes for Nissen fundoplication, and the total operating room time was 250 +/- 60 minutes. Surgeons found dissection, suturing, and knot tying easier than with conventional laparoscopy. None of the surgeons thought the lack of touch feedback (haptics) was crucial. CONCLUSION: Robotic surgery offers increased dexterity to the pediatric minimally invasive surgeon, but procedures require more time, and there is no defined patient benefit. The fact that robotic surgery digitalizes minimally invasive surgery creates exciting possibilities for training surgeons, planning operations, and performing surgery at great distances from the operator.     

Early antibiotic treatment for severe acute necrotizing pancreatitis: a randomized, double-blind, placebo-controlled study

BACKGROUND & AIMS: In patients with severe, necrotizing pancreatitis, it is common to administer early, broad-spectrum antibiotics, often a carbapenem, in the hope of reducing the incidence of pancreatic and peripancreatic infections, although the benefits of doing so have not been proved. METHODS: A multicenter, prospective, double-blind, placebo-controlled randomized study set in 32 centers within North America and Europe. Participants: One hundred patients with clinically severe, confirmed necrotizing pancreatitis: 50 received meropenem and 50 received placebo. Interventions: Meropenem (1 g intravenously every 8 hours) or placebo within 5 days of the onset of symptoms for 7 to 21 days. Main Outcome Measures: Primary endpoint: development of pancreatic or peripancreatic infection within 42 days following randomization. Other endpoints: time between onset of pancreatitis and the development of pancreatic or peripancreatic infection; all-cause mortality; requirement for surgical intervention; development of nonpancreatic infections within 42 days following randomization. RESULTS: Pancreatic or peripancreatic infections developed in 18% (9 of 50) of patients in the meropenem group compared with 12% (6 of 50) in the placebo group (P = 0.401). Overall mortality rate was 20% (10 of 50) in the meropenem group and 18% (9 of 50) in the placebo group (P = 0.799). Surgical intervention was required in 26% (13 of 50) and 20% (10 of 50) of the meropenem and placebo groups, respectively (P = 0.476). CONCLUSIONS: This study demonstrated no statistically significant difference between the treatment groups for pancreatic or peripancreatic infection, mortality, or requirement for surgical intervention, and did not support early prophylactic antimicrobial use in patients with severe acute necrotizing pancreatitis.     

Role of preoperative arthrography in early Perthes disease as a decision-making tool. Is it really necessary?

Arthrograms are commonly done in conjunction with an examination under anaesthesia (EUA), before any surgical intervention in Perthes disease. This usually is done as an independent day case procedure in the radiology department. The aim of this study is to confirm that the affected hip meets the prerequisites of a containment procedure. This study was carried out to investigate whether arthrogram findings ever altered the preoperative clinical decision of proposed osteotomy.One hundred and seven cases were reviewed retrospectively. Forty patients were excluded. Decision was not changed in 62 out of 67 hips, after the procedure. Five patients required different management following arthrogram and this was based mainly on EUA findings. EUA under image intensification helps the surgeon to decide the angle of varus osteotomy, required to contain the femoral head in the acetabulum and confirms an adequate range of abduction to undertake the procedure. This quick assessment can be done at the time of surgery under the same anaesthesia without the need for arthrography.Our findings question the role of arthrography as a routine before surgical intervention in Perthes disease and suggest that it may represent an unnecessary cost. We now reserve arthrography for cases of late Perthes disease where valgus osteotomy may be appropriate or for those unusual or questionable cases where clinical findings are inconclusive and therefore the type or appropriateness of treatment is uncertain.     

Micropapillary bladder cancer: Current treatment patterns and review of the literature

ObjectivesNo guidelines exist for the management of micropapillary bladder cancer (MPBC) and most reports of this variant of urothelial carcinoma are case series comprising small numbers of patients. We sought to determine current practice patterns for MPBC using a survey sent to the Society of Urologic Oncology (SUO) and to present those results in the setting of a comprehensive review of the existing literature.Materials and methodsA survey developed by the Translational Science Working Group of the Bladder Cancer Advocacy Network–sponsored Think Tank meeting was distributed to members of the SUO. The results from 118 respondents were analyzed and presented with a literature review.ResultsMost survey respondents were urologists, with 80% considering bladder cancer their primary area of interest. Although 78% of the respondents reported a dedicated genitourinary pathologist at their institution, there were discrepant opinions on how a pathologic diagnosis of MPBC is determined as well as variability on the proportion of MPBC that is clinically significant. Among them, 78% treat MPBC differently than conventional urothelial carcinoma, with 81% reporting that they would treat cT1 MPBC with upfront radical cystectomy. However, the respondents had split opinions regarding the sensitivity of MPBC to cisplatin-based chemotherapy, which affected utilization of neoadjuvant chemotherapy in muscle-invasive disease.ConclusionsThe management of MPBC is diverse among members of the SUO. Although most favors early cystectomy for cT1 MPBC, there is no consensus on the use of neoadjuvant chemotherapy for muscle-invasive MPBC.     

The Efficacy of Vitamin D Supplementation During a Prolonged Submarine Patrol

Submariners spend prolonged periods submerged without sunlight exposure and may benefit from vitamin D supplementation to maintain vitamin D status. The primary objective of this study was to determine the efficacy of daily vitamin D supplementation on maintenance of 25-hydroxyvitamin D (25(OH)D) during a 3-month submarine patrol. Submariners were randomly divided into three groups: placebo (n = 16), 1,000 IU/day (n = 20), or 2,000 IU/day (n = 17). Anthropometrics, self-reported dietary calcium and vitamin D intake, serum markers of vitamin D and bone metabolism, and peripheral quantitative computed tomography (pQCT) parameters of the tibia were determined before and after the patrol. Prior to departure, 49 % of the subjects were vitamin D insufficient (<50 nmol/L). Following the patrol, 25(OH)D increased in all groups (p < 0.001): 3.3 ± 13.1 (placebo), 4.6 ± 11.3 (1,000 IU/day), and 13 ± 14 nmol/L (2,000 IU/day). The changes in 25(OH)D levels were dependent upon the baseline concentration of 25(OH)D and body mass (p < 0.001). Osteocalcin increased by 38 % (p < 0.01), and pQCT analyses revealed small, yet significant increases in indices of tibial structure and strength (p < 0.05) that were independent of supplementation. These data suggest that vitamin D status was low prior to the patrol, and the subsequent changes in vitamin D status were dependent on the baseline 25(OH)D levels and body mass. Furthermore, short-term skeletal health does not appear to be negatively affected by 3 months of submergence in spite of a suboptimal response to vitamin D supplementation.