Application of PEEP using the i-gel during volume-controlled ventilation in anesthetized, paralyzed patients

Purpose

This prospective, randomized trial was designed to assess whether the i-gel supraglottic airway device is suitable for volume-controlled ventilation while applying positive end-expiratory pressure (PEEP) of 5 cmH₂O under general anesthesia. It was believed that this device might improve arterial oxygenation.

Methods

Forty adult patients (aged 20–60 years) scheduled for elective orthopedic surgery were enrolled in this study. Twenty patients were ventilated without external PEEP [zero positive end-expiratory pressure (ZEEP) group], and the other 20 were ventilated with PEEP 5 cmH₂O (PEEP group) after placing an i-gel device. Volume-controlled ventilation at a tidal volume (TV) of 8 ml/kg of ideal body weight, leak volume, and arterial blood gas analysis were investigated.

Results

The incidences of a significant leak were similar in the ZEEP and PEEP groups (3/20 and 1/20, respectively; P = 0.605), as were leak volumes. No significant PaO₂ difference was observed between the two groups at 1 h after satisfactory i-gel insertion (215 ± 38 vs. 222 ± 54; P = 0.502).

Conclusions

The use of an i-gel during PEEP application at 5 cmH₂O did not increase the incidence of a significant air leak, and a PEEP of 5 cmH₂O failed to improve arterial oxygenation during controlled ventilation in healthy adult patients.     

Proper preparation to reduce endoscopic reexamination due to food residue after distal gastrectomy for gastric cancer

Background

Reducing food residue by proper preparation methods before endoscopy after distal gastrectomy can increase the quality of examination and decrease patient discomfort. We evaluated the risk factors for food residue and proper methods of preparation for endoscopy after distal gastrectomy.

Methods

Follow-up endoscopy with questionnaires was performed on 1,001 patients who underwent distal gastrectomy at Asan Medical Center between December 2010 and July 2011.

Results

Endoscopic examination failed in 94 patients (9.4 %) as a result of large amounts of food residue. Rates of failure were significantly higher in patients who ate a regular diet rather than a soft diet at last dinner before examination (13.9 vs. 6.1 %, p = 0.050), and in those who ate lunch rather than not eating lunch on the day before examination (14.6 vs. 7.7 %, p = 0.020). Multivariate analysis showed that the rate of failed examination was lower in patients who had a history of abdominal surgery (p = 0.011), those who ate a soft (p < 0.001) or liquid (p = 0.003) diet as a last meal rather than a regular diet, those who underwent Billroth I rather than Billroth II reconstruction (p = 0.035), patients with longer fasting time (p = 0.009), and those with a longer gastrectomy-to-endoscopy time interval (p < 0.001).

Conclusions

Patients who undergo follow-up endoscopy after surgery should fast more than 18 h and ingest a soft or liquid diet on the day before examination.     

Robot-assisted Posterior Retroperitoneoscopic Adrenalectomy Using Single-port Access: Technical Feasibility and Preliminary Results

Background

Posterior retroperitoneoscopic adrenalectomy (PRA) has several benefits compared with transperitoneal adrenalectomy in that it is safe and has a short learning curve. In addition, it provides direct short access to the target organ, prevents irritation to the intraperitoneal space, and does not require retraction of adjacent organs.1 ^– 3 We have performed several cases of robot-assisted PRA using single-port access for small adrenal tumors. This multimedia article introduces the detailed methods and preliminary results of this procedure.

Methods

Five patients underwent single-port robot-assisted PRA between March 2010 and June 2011 at our institution. During the procedure, patients were placed in a prone jackknife position with their hip joints bent at a right angle (Fig. 1). A 3 cm transverse skin incision was made just below the lowest tip of the 12th rib (Fig. 2), and the Glove port (Nelis, Kyung-gi, Korea) was placed through the skin incision while maintaining pneumoretroperitoneum (Fig. 3). CO₂ was then insufflated to a pressure of 18 mm Hg to create an adequate working space. A 10 mm robotic camera with a 30-degree up view was placed at the center of the incision through the most cephalic portion of the Glove port. A Maryland dissector or Prograsp forceps (Intuitive Surgical, Inc., Sunnyvale, CA) was placed on the medial side of the incision, and Harmonic curved shears (Intuitive Surgical) were placed on the lateral side of the incision (Fig. 4). Using the Maryland dissector and the harmonic curved shears, the Gerota fascia is opened, perinephric fat is dissected, and the kidney upper pole is mobilized to expose the adrenal gland (Fig. 5). Gland dissection starts with lower margin detachment from the upper kidney pole in a lateral to medial direction (Fig. 6). After dissecting the adrenal gland from surrounding adipose tissue and medial isolation of the adrenal central vein, the vessel is ligated with a 5 mm hemolock clip (Fig. 7). Patient clinicopathologic data were analyzed retrospectively.

Results

The mean patient age was 56.6 ± 8.7 (range, 47–69) years. Right and left side approaches were used in two and three patients, respectively. All cases were adrenal cortical adenoma. The mean tumor size was 1.48 ± 0.28 (range, 1.0–1.7) cm. The mean surgery duration (skin to skin) was 159.4 ± 57.6 (range, 103–245) minutes, and the mean estimated blood loss was 46.0 ± 56.8 (range, 5–120) ml. The average time to oral intake and postoperative hospital stay were 0.65 ± 0.11 (range, 0.54–0.79) days and 4.0 ± 2.23 (range, 3–8) days, respectively. There were no conversions to open surgery or postoperative compli- cations.

Discussion

Some trials of minimally invasive single-access surgery of the adrenal gland have recently been performed.4 ^, 5 However, these new techniques have several limitations as a result of restrictions on instrumentation movement because of the small access ports used and relatively low-quality images produced. The recent introduction of the da Vinci S surgical robot system (Intuitive Surgical) to endoscopic surgery has improved instrumental dexterity and provided the surgeon with an ergonomically designed operating system. This system is also potentially safer and more meticulous in performing operations than endoscopic procedures as a result of a 3-D, magnified, stable operative view.6 ^, 7 The advantages of the da Vinci S surgical robot system and the numerous benefits of the posterior retroperitoneal approach motivated us to utilize single-port robot-assisted PRA. The primary selection criteria were small tumor size and a minimal amount of periadrenal fatty tissue because robot-assisted PRA using single-port access provides a small operative space, which causes manipulation problems when tumors are large. To ensure the safe application of these new techniques, we recommend that novice surgeons begin using single-port robot-assisted PRA for smaller tumors < 2 cm in patients with a body mass index of < 30 kg/m², gradually extending the size and body mass index as they accumulate experience. Although robot-assisted PRA using single-port access could not be compared with the other robotic adrenalectomy techniques in this study, the potential advantages of this approach compared to conventional robot-assisted transperitoneal adrenalectomy include a reduction in postoperative ileus, bacterial contamination, and intestinal complications because the peritoneal cavity is not opened, in addition to a reduction in postoperative pain because of its minimally invasive nature.

Conclusions

Our initial experiences with robot-assisted PRA using single-port access assured us of its safety and feasibility for the resection of small adrenal tumors. Although single-port robot-assisted PRA appears to be safe and feasible, further experience and research is required to optimize patient selection criteria and verify its advantages over the traditional three-incision PRA technique.     

P16 Hypermethylation Predicts Surgical Outcome Following Curative Resection of Mid/Distal Bile Duct Cancer

Background

Bile duct cancer has very poor prognosis. Important prognostic factors include the TNM stage, cell differentiation, and histologic type; however, we often observe patients whose prognosis is not consistent with the TNM stage. Additional prognostic indicators are mandatory to complement those used presently. We evaluated the hypermethylation status of genes for the power to predict overall survival following curative resection of mid/distal bile duct cancer.

Methods

Pyrosequencing hypermethylation status at the loci of interest was analyzed in 65 mid/distal bile duct carcinoma specimens obtained at Severance Hospital of Yonsei University College of Medicine from January 2000 to December 2006.

Results

Significant methylation frequencies (MtI >5 %) were obtained for 5 genes (which P16 [17 %], DAPK [54 %], E-cadherin [60 %], RASSF-1 [46.2 %], and hMLH1 [43.1 %]). MtI status of P16, DAPK, and RASSF-1 were correlated with perineural invasion, tumor depth, and age, respectively. In the multivariate analysis of overall survival, the presence of lymph node metastasis and P16 methylation status were identified as independent prognostic factors for overall survival. Patients with unmethylated of P16 had the 3- and 5-year survival rates of 60.8 and 54.9 %, respectively. In patients with hypermethylated P16, the 3- and 5-year survival rates were 27.3 and 0.0 %, respectively.

Conclusions

P16 hypermethylation and lymph node metastasis may predict overall survival in curative resected mid/distal bile duct cancer. Classification of mid/distal bile duct cancer by both genetic and epigenetic profiles may improve the accuracy in predicting outcome and the effectiveness of tailored therapy in these diseases.     

BRAF V600E Mutation Analysis in Papillary Thyroid Carcinomas by Peptide Nucleic Acid Clamp Real-time PCR

Background

Activating somatic mutation of the BRAF ^V600E has been identified as the most common genetic event in papillary thyroid carcinoma (PTC) with a variable frequency (32–87 %) in different series by different methods. The BRAF ^V600E mutation is associated with various clinicopathological parameters. The mutation is an important factor for the management of the PTC patients. The objective of this study was to detect the BRAF ^V600E mutation in PTCs by peptide nucleic acid (PNA) clamp real-time PCR and to analyze the results with clinicopathological parameters.

Methods

We performed genetic analysis of BRAF ^V600E by PNA clamp real-time PCR in 211 PTCs in Korea, stratified by clinicopathological parameters.

Results

The BRAF ^V600E mutation was detected in 90 % of PTC cases, and it occurred significantly more often in female patients than in male patients (p = 0.001). The clinicopathological parameters of age, tumor size, and disease stage were not associated with the BRAF ^V600E mutation, while extrathyroid invasion (p = 0.031), lymph nodal metastasis (p = 0.002), and tumor multiplicity (p = 0.020) were.

Conclusions

The prevalence (90 %) of the BRAF ^V600E mutation in this study is the highest ever reported, confirming the key role of this mutation in PTC tumorigenesis. The BRAF ^V600E mutation was associated with aggressive clinical behaviors including extrathyroid invasion, lymph nodal metastasis and tumor multifocality. The PNA clamp real-time PCR method for the BRAF ^V600E mutation detection is sensitive and is applicable in a clinical setting.