Anesthetic Considerations for Carbon Dioxide Emboli in Patients with Obesity - A Case Report.

Gas embolization is a rare but potentially deadly complication of any laparoscopic surgery. There has only been one other report of gas emboli in patients undergoing bariatric surgery. We present a case of gas embolization in a young female patient undergoing Roux-en-Y gastric bypass. Onset of gas embolus was identified by a dramatic drop in End Tidal Carbon Dioxide (ETCO2) followed by drops in blood pressure, heart rate, and oxygen saturation over the following 15 minutes before the patient was stabilized and transferred to the ICU. The surgery was completed three days later without incident, and extensive hepatomegaly was identified. A discussion on pre-operative evaluation, special considerations, and acute management of gas embolization in patients with obesity ensues. We highlight the emerging Jain's point for insufflation, the potential for ultrasound-guided Verres needle insertion, and the paucity of literature evaluating the risk, incidence, and outcomes of gas embolization in patients with obesity.

Laparoscopic Resection of a Congenital Gastric Diverticulum that was Found Incidentally on Imaging: A Case Report.

Gastric diverticula are quite rare and can be either acquired or congenital. Resection is recommended when the diverticula are large (>4 cm), PPI therapy does not relieve symptoms, and/or complications arise. We present a case of a patient with a long-standing history of symptoms related to a congenital gastric diverticulum that had been found incidentally on imaging during a workup for possible small bowel obstruction. The patient underwent a successful laparoscopic, robotic assisted surgical resection of the congenital gastric diverticulum with complete relief of his symptoms.

Laparoscopic Pediatric Inguinal Hernia Repair: Overview of "True Herniotomy" Technique and Review of Current Evidence.

Inguinal hernia repair is one of the most commonly performed operations in the pediatric population. While the majority of pediatric surgeons routinely use laparoscopy in their practices, a relatively small number prefer a laparoscopic inguinal hernia repair over the traditional open repair. This article provides an overview of the three port laparoscopic technique for inguinal hernia repair, as well as a review of the current evidence with respect to visualization and identification of hernias, recurrence rates, operative times, complication rates, postoperative pain, and cosmesis. The laparoscopic repair presents a viable alternative to open repair and offers a number of benefits over the traditional approach. These include superior visualization of the relevant anatomy, ability to assess and repair a contralateral hernia, lower rates of metachronous hernia, shorter operative times in bilateral hernia, and the potential for lower complication rates and improved cosmesis. This is accomplished without increasing recurrence rates or postoperative pain. Further research comparing the different approaches, including standardization of techniques and large randomized controlled trials, will be needed to definitively determine which is superior.

Comparison of a subrank to a full-rank time-reversal operator in a dynamic ocean.

This paper investigates the application of time-reversal techniques to the detection and ensonification of a target of interest. The focusing method is based on a generalization of time-reversal operator techniques. A subrank time-reversal operator is derived and implemented using a discrete set of transmission beams to ensonify a region of interest. In a dynamic ocean simulation, target focusing using a subrank matrix is shown to be superior to using a full-rank matrix, specifically when the subrank matrix is captured in a period shorter than the coherence time of the modeled environment. Backscatter from the point target was propagated to a vertical 64-element source-receiver array and processed to form the sub-rank time-reversal operator matrix. The eigenvector corresponding to the strongest eigenvalue of the time-reversal operator was shown to focus energy on the target in simulation. Modeled results will be augmented by a limited at-sea experiment conducted on the New Jersey shelf in April-May 2004 measured low-frequency backscattered signal from an artificial target (echo repeater).

Killing tumor cells: the effect of photodynamic therapy using mono-L-aspartyl chlorine and NS-398.

BACKGROUND: Photodynamic therapy (PDT) is a useful treatment for malignant tumors. PDT involves the administration of a photosensitive drug that is selected by neoplastic tissues and their vasculature. One such photosensitizer is mono-l-aspartyl chlorine e6 (NPe6). Recent evidence suggests that the presence of the cyclooxygenase-2 (COX-2) inhibitor NS-398 may potentiate the effect of photosensitizing agents. This study was designed to determine if the addition of NS-398 to NPe6-induced PDT in single or fractionated dosing would result in greater tumor kill. METHODS: Colon-38 tumor was subcutaneously implanted into both flanks of mice and allowed to grow to 0.5 to 1.0 cm. Mice were randomly allocated to 5 groups: (1) single dose of NPe6; (2) fractionated dose of NPe6; (3) NS-398 only; (4) single dose of NPe6 + NS-398; and (5) fractionated dose of NPe6 + NS-398. The left flank was shielded from exposure to irradiation. Tumor size was measured before initiation of PDT and at the time of sacrifice. RESULTS: The initial tumor weights of both flanks were not significantly different between all groups. Tumor weights at the time of death after PDT using NPe6 were significantly less than their paired tumors in the untreated flanks (P <0.0001). Tumor weights in the treated flanks were significantly less in the group receiving the fractionated dosing of NPe6 as compared to the single dose of NPe6 (P = 0.0037). NS-398 plus the single dose of NPe6 significantly decreased tumor weight in the PDT-treated flank (P = 0.035) at a level equivalent to that observed with fractionated dosing of the photosensitizer in the absence of NS-398. NS-398 did not significantly further decrease tumor weight in the group that received the fractionated dose of NPe6. CONCLUSIONS: Fractionated dosing of NPe6 demonstrated the best tumor kill. However, NS-398 did not potentiate the effect of PDT using fractionated dosing of NPe6. While PDT using the single NPe6 dose significantly decreased tumor weight, the addition of NS-398 potentiated the killing effect.

Effects of photodynamic therapy using a fractionated dosing of mono-L-aspartyl chlorin e6 in a murine tumor.

One of the 'second generation' photosensitizing agents is N-acetyl chlorin e6 (NPe6). This product has a strong absorbance band at 665 nm, permitting treatment at a greater depth of tumor than earlier agents based on porphyrin structures. We examined the effects of fractionated drug administration on photodynamic efficacy. Prior studies had shown that it is the level of NPe6 in the circulation that predicts for photodynamic efficacy, indicating vascular shut-down to be the predominant mode of tumor control. Although pharmacokinetic studies revealed that >99% of NPe6 was lost from the circulation, it appears that a fractionated dosage protocol can promote photodamage to neoplastic tissue in vivo. This study also indicated the potential utility of an implantable micro array for tumor irradiation.

Photodynamic therapy for carcinoma in situ of the anus.

HYPOTHESIS: Photodynamic therapy (PDT) for carcinoma in situ of the anus is an alternative to surgical excision in patients who are seropositive for human immunodeficiency virus (HIV). DESIGN: Before-after trial. Settings Tertiary referral center. PATIENTS: Twelve HIV-seropositive patients who were actively being treated for AIDS with high-grade dysplasia on anal Papanicolaou test results had site-directed biopsies of acetowhitening foci immediately after application of dilute acetic acid. Biopsy results showed that 5 patients had anal carcinoma in situ. These patients were given the photosensitizer delta-aminolevulinic acid orally. Four to 4.25 hours later, the entire anal circumference was treated with PDT. All 5 patients, after being treated with PDT, had repeated Papanicolaou tests at monthly intervals. If acetowhitening occurred at the fifth month, site-directed biopsy was done. MAIN OUTCOME MEASURES: Anal cytologic examination by Papanicolaou test and site-directed biopsy if acetowhitening was found at 5 months in order to determine effectiveness of PDT in downstaging cytologic findings. RESULTS: All patients had a consistent downgrading of cytologic findings during the 5 months of follow-up. Papanicolaou test results showed 2 patients had no dysplasia, 2 had mild dysplasia, and 1 had moderate dysplasia. Moderate dysplasia was confirmed by site-directed biopsy results. No complications of PDT occurred, but all 5 patients developed various abnormalities in liver function test results that returned to baseline values within 2 weeks; this also has been noted in patients ingesting delta-aminolevulinic acid who are presumably HIV seronegative. CONCLUSION: In a group of patients who are at high risk for recurrence irrespective of initial treatment, PDT can be used as a successful alternative to surgical excision for anal carcinoma in situ.

Ligation of the pancreatic duct during difficult operative circumstances.

BACKGROUND: The current approach to managing the distal pancreas after pancreaticoduodenectomy is to anastomose the stump to either the jejunum or stomach, but pancreatic ductal occlusion without anastomosis of the pancreatic remnant remains an option during difficult operative circumstances. This article describes some situations in which distal pancreatic ductal ligation may be of use and reviews the morbidity associated with this procedure. STUDY DESIGN: Review was done of a prospectively kept database of operative and pathology reports and of both immediate and 3-month to 6-year followup data of seven patients who underwent ductal occlusion during pancreaticoduodenectomy or central pancreatectomy. RESULTS: Ductal occlusion was performed in three circumstances: 1. necessity for expedient termination of the operation; 2. short jejunal mesentery allowing only a tension-free biliary or pancreatic anastomosis; and 3. massive jejunal edema that would result in a tenuous anastomosis. Two patients developed a fistula. One patient had dense residual pancreatic fibrosis, which resolved after 5 days; the other patient had a normal residual pancreas and subsequently underwent a pancreaticojejunostomy. Three patients developed acute pancreatitis (two had a normal and one had mild to moderate fibrosis in the residual pancreas) and one of these developed a peripancreatic abscess and late pseudocyst. Four patients with dense fibrosis did not develop acute pancreatitis. No patient developed either overt or worsening diabetes during the limited followup. None of the patients required enzyme supplementation, but all voluntarily maintained a low-fat diet. CONCLUSIONS: The development of complications after ductal ligation appears to be associated with the degree of fibrosis of the residual distal gland. Acute pancreatitis and fistula are the major complications but are associated with a low mortality. Diabetes is a potential late problem. The morbidity associated with ductal ligation is generally accepted as being greater than anastomosis, but ligation can be considered as an alternative in difficult circumstances where anastomosis of the distal pancreatic stump is believed to be unwise.

Exploring the chemical enhancement for surface-enhanced Raman scattering with Au bowtie nanoantennas.

Single metallic bowtie nanoantennas provide a controllable environment for surface-enhanced Raman scattering (SERS) of adsorbed molecules. Bowties have experimentally measured electromagnetic enhancements, enabling estimation of chemical enhancement for both the bulk and the few-molecule regime. Strong fluctuations of selected Raman lines imply that a small number of p-mercaptoaniline molecules on a single bowtie show chemical enhancement >10(7), much larger than previously believed, likely due to charge transfer between the Au surface and the molecule. This chemical sensitivity of SERS has significant implications for ultra-sensitive detection of single molecules.

Toward nanometer-scale optical photolithography: utilizing the near-field of bowtie optical nanoantennas.

Optically resonant metallic bowtie nanoantennas are utilized as fabrication tools for the first time, resulting in the production of polymer resist nanostructures <30 nm in diameter at record low incident multiphoton energy densities. The nanofabrication is accomplished via nonlinear photopolymerization, which is initiated by the enhanced, confined optical fields surrounding the nanoantenna. The position, size, and shape of the resist nanostructures directly correlate with rigorous finite-difference time-domain computations of the field distribution, providing a nanometer-scale measurement of the actual field confinement offered by single optical nanoantennas. In addition, the size of the photoresist regions yields strong upper bounds on photoacid diffusion and resist resolution in SU-8, demonstrating a technique that can be generalized to the study of many current and yet-to-be-developed photoresist systems.

A multicenter Phase I safety study of intratumoral photoactivation of talaporfin sodium in patients with refractory solid tumors.

BACKGROUND: Photodynamic therapy (PDT) currently is approved for the palliative treatment of malignancies of the aerodigestive tract using laser-activated porfimer sodium. A new approach has been developed, based on intratumoral placement of a nonlaser light device that activates talaporfin sodium, that may expand the use of PDT to include a broader range of treatment-resistant malignancies. The safety of this approach was assessed in a Phase I study in patients with locally advanced, refractory tumors. METHODS: Twenty-one patients with radiation-resistant or chemotherapy-resistant or inoperable malignancies were enrolled in four cohorts representing four light doses. Patients were treated with a single intratumoral light device and a fixed photosensitizer dose. Safety assessments were based on review of adverse events (AEs) and serious adverse events (SAEs), and independent evaluation of computed tomography (CT) images. RESULTS: The observed occurrence of treatment-related AEs and SAEs was minimal. No cutaneous phototoxicity was observed in any patient. The overall observed tumor response rate was 33%. CONCLUSIONS: Photoactivation of talaporfin sodium using intratumoral nonlaser light was found to be safe in the patient population of the current study at all light dose levels tested.