Kazusada Shirao

Causes of Nitrous Oxide Contamination in Operating Rooms

BACKGROUND To reduce the ambient concentration of waste anesthetic agents, exhaust gas scavenging systems are standard in almost all operating rooms. The incidence of contamination and the factors that may increase the concentrations of ambient anesthetic gases have not been evaluated fully during routine circumstances, however. METHODS Concentrations of nitrous oxide (N2O) in ambient air were monitored automatically in 10 operating rooms in Kagoshima University Hospital from January to March 1997. Ambient air was sampled automatically from each operating room, and the concentrations of N2O were analyzed every 22 min by an infrared spectrophotometer. The output of the N2O analyzer was integrated electronically regarding time, and data were displayed on a monitor in the administrative office for anesthesia supervisors. A concentration of N2O > 50 parts per million was regarded as abnormally high and was displayed with an alarm signal. The cause of the high concentration of N2O was then sought. RESULTS During the 3-month investigation, N2O was used in 402 cases. Abnormally high concentrations of N2O were detected at some time during 104 (25.9%) of those cases. The causes were mask ventilation (42 cases, 40.4% of detected cases), unconnected scavenging systems (20 cases, 19.2%), leak around uncuffed pediatric endotracheal tube (13 cases, 12.5%), equipment leakage (12 cases, 11.5%), and others (17 cases, 16.4%). CONCLUSIONS N2O contamination was common during routine circumstances in our operating rooms. An unconnected scavenging system led to the highest concentrations of N2O recorded. Proper use of scavenging systems is necessary if contamination by anesthetic gas is to be limited.

Assessment of cervical lymph node metastasis in esophageal carcinoma using ultrasonography.

OBJECTIVE To evaluate the efficacy of ultrasonography for the diagnosis of cervical lymph node metastasis in esophageal carcinoma. SUMMARY BACKGROUND DATA Ultrasound (US) examination is useful for diagnosing lymph node metastasis. However, few reports have examined its role in the decision to perform cervical lymph node dissection in esophageal carcinoma. METHODS Ultrasound examination was performed to evaluate cervical lymph node metastasis in 519 patients with esophageal carcinoma. The patients were divided into 5 groups according to treatment received: group 1, 153 patients who underwent curative resection of primary tumor by right thoracotomy and complete bilateral cervical lymphadenectomy; group 2, 112 patients who underwent curative resection of primary tumor by right thoracotomy but without cervical lymphadenectomy; group 3, 78 patients who underwent esophagectomy by left thoracotomy or blunt dissection with or without removal of cervical lymph nodes; group 4, 76 patients with palliative resection without cervical lymphadenectomy; and group 5, 100 patients without any surgical treatment. US diagnosis was compared with histologic findings or cervical lymph node recurrence. RESULTS Lymph node metastasis was detected in 30.8% of patients (160/519). The sensitivity, specificity, and accuracy of US diagnosis in group 1 were 74.5%, 94.1%, and 87.6%, respectively. Cervical lymph node recurrence was seen in 7 patients (4.6%) in group 1, in 4 patients (3.6%) in group 2, and 3 patients (3.8%) in group 3. Although the incidence of cervical lymph node metastasis as determined by US examination was high in groups 4 and 5, almost none of the patients died of cervical lymph node metastasis. CONCLUSIONS Ultrasound examination plays a useful role in the decision to perform cervical lymph node dissection in patients with esophageal carcinoma, particularly in those with potentially curative dissection.

Mucosal Squamous Cell Carcinoma of the Esophagus: A Clinicopathologic Study of 30 Cases

A clinicopathologic study was carried out on 30 patients with mucosal esophageal cancer (MEC). The depth of cancer invasion was subdivided histologically into three categories: m1 = carcinoma in situ (intraepithelial carcinoma) or carcinoma with questionable invasion beyond the basal membrane; m2 = cancer invasion confined to the lamina propria, and m3 = cancer reaching to or infiltrating into the muscularis mucosae. Lymph node metastases and lymphatic invasion were found only in the tumors reaching or infiltrating the muscularis mucosae (m3). The maximum histologic vertical extent of the tumors was more than 1 mm in 4 of 5 patients with lymph node metastasis or lymphatic invasion. None of the patients died of recurrent esophageal disease, and 3 of the 6 patients who had a second primary tumor died of this other malignancy. It is critical to distinguish between m1, m2 and m3 tumors to plan a treatment strategy, including an endoscopic mucosal resection.

Section 2. Thyroid: Anterior chest wall approach for video-assisted thyroidectomy using a modified neck skin lifting method

Neck endoscopic surgery is likely to prove less invasive and more cosmetically advantageous than conventional methods. The surgical procedure used for 42 consecutive patients undergoing video-assisted thyroidectomy by the anterior chest wall approach is described herein. A 3-4 cm incision was made at the anterior chest wall 2 cm below the clavicle on the tumor side. Two Kirshner wires connected to a winching device were horizontally inserted beneath the skin in order to lift the neck skin. Specially made retractors were passed through the chest wall wound to the lateral neck bilaterally. Strap muscle on the tumor side was retracted laterally and the thyroid tumor was retracted medially. A suitable working space was thus created using this modified neck lifting method without gas insufflation. All patients underwent video-assisted thyroidectomy utilizing an anterior chest wall approach without conversion to open thyroidectomy. Mean operative time from incision to removal of the tumor was 145 min. Mean tumor size was 4.1 cm (range: 2.0-7.5 cm). The advantage of our approach is that the scar below the clavicle is invisible under normal clothing. In addition, conventional instruments for open thyroidectomy can be used. In our method, the thyroid tumor and trachea are palpable and some parts of the operation can be conducted under direct visualization if the assistant retracts the anterior chest wall wound upward. Video-assisted thyroidectomy utilizing an anterior chest wall approach is cosmetically less invasive, particularly for women who are frequently nervous about operative scars on the neck.

Does preoperative chemotherapy cause adverse effects on the perioperative course of patients undergoing esophagectomy for carcinoma

The aim of this study was to clarify whether preoperative chemotherapy caused adverse effects on the perioperative course of patients undergoing esophagectomy. A total of 42 esophageal cancer patients were entered into a randomized trial and were analyzed. Twenty-one patients were assigned to immediate surgery (Surgery Group). The other 21 received two 5-day courses of chemotherapy comprising cisplatin (70 mg/m2) on day 1, and fluorouracil (700 mg/m2) and leucovorin (20 mg/m2) on each of days 1 to 5 (chemotherapy group). Hospital mortality comprised of one patient (2.3%) who had undergone an operation in the beginning of this series at 21 days after chemotherapy. Thereafter, the interval between the chemotherapy and operation was prolonged, with the average being 35 +/- 7 days. Preoperatively, both the lymphocyte counts and serum albumin levels were not increased in the chemotherapy group of patients even though their body weights increased. In the chemotherapy group, the operation time and the blood loss were increased and, on the 1st postoperative day, the development of systemic inflammatory response syndrome was high but the level of C-reactive protein was low. The incidence of positive microbial cultures of sputum and/or wound discharge within 8 postoperative days was higher in the chemotherapy group (42.9%) than in the surgery group (4.8%). The host defense damage caused by chemotherapy may be prolonged and may show adverse effects in patients undergoing esophagectomy in the early postoperative period. Minimally, a 4-week interval between the completion of chemotherapy and operation is recommended for preventing surgical mortality related to the preoperative chemotherapy.

Lymph node metastasis and the recurrence of esophageal carcinoma with emphasis on lymphadenectomy in the neck and superior mediastinum

A series of 335 patients with squamous cell carcinoma of the thoracic esophagus undergoing resection and reconstruction via a right thoracotomy and laparotomy with cervical anastomosis between 1973 and 1990, were reviewed. Prior to 1982, the removal of lymph nodes was limited to the nodes in the mediastinum below the tracheal bifurcation and upper abdomen (142 patients). Nodal metastases were found in 89 of these patients at operation. The upper abdominal nodes were the most frequent sites of metastasis (47.2%). None of the 38 patients with positive nodes sampled from the neck and superior mediastinum survived for more than 45 months. In the 50 patients with recurrences, 30 were in the neck and/or superior mediastinum. During or after 1983, the superior mediastinal nodes, particularly the bilateral recurrent nerve nodal chains, were routinely removed (193 patients). Nodal metastasis was proven in 131 of the 193 patients, in whom 87 (45.1%) had metastasis in the neck and superior mediastinum. Eleven of these 87 patients survived for 45 months or more. In the 61 patients with recurrences, 20 were in the neck and/or superior mediastinum. These data suggest that recurrent nerve nodal chains should be removed to improve survival in patients with esophageal carcinoma.

Difference in incidence and transmission mode of methicillin-resistant Staphylococcus aureus among surgery, orthopedics, and pediatrics wards : A prospective study at a University Hospital

The incidence and circumstances of colonization by methicillin-resistant Staphylococcus aureus were prospectively investigated. Among 404 patients, 15 (3.7%) were carriers on admission, and 43 (10.6%) became colonized, mainly after surgical operation. A different mode of transmission was suggested in each ward.

Fat Emulsion Administration in the Early Postoperative Period in Patients Undergoing Esophagectomy for Carcinoma Depresses Arachidonic Acid Metabolism in Neutrophils

The aim of this study was to evaluate the effect of fat emulsion administration on neutrophil arachidonic acid and leukotriene B4 (LTB4) generation in surgically stressed patients. Total parenteral nutrition was administered to 17 patients for 2 wk after esophagectomy for carcinoma. Eight patients received fat with glucose (fat group, 30% of total calories) and 9 patients received glucose (glucose group) as a non-protein calorie source from the day of the operation to the seventh postoperative day (POD), and they gradually were converted to enteral nutrition during the second postoperative week. The arachidonic acid in the fat group decreased in the serum from POD 4 to 14. and in neutrophils from 12 h after the beginning of surgery to POD 14, compared to preoperative levels. LTB4 production by A23187-stimulated neutrophils was highest 6 h after the beginning of surgery, when neutrophil arachidonic acid concentration was decreasing, and then fell below the preoperative value from POD 4 to 14 in both groups. LTB4 production on POD 14 was lower in the fat group than in the glucose group. Biosynthesis of arachidonic acid from linoleic acid is inhibited in surgically stressed patients receiving fat emulsion, resulting in the diminished synthesis of LTB4 by neutrophils. The decrease in LTB4 may diminish chemotactic and chemokinetic signals to other leukocytes.

Diffusely Infiltrative Squamous Cell Carcinoma of the Esophagus

This study was designed to clarify the clinical and pathologic features of diffusely infiltrative squamous cell carcinoma of the esophagus. Diffusely infiltrative squamous cell carcinomas were classified grossly into two types, namely, scirrhous carcinoma and nonscirrhous carcinoma. There were seven patients with the former type and three with the latter type. Scirrhous-type carcinoma was associated with a prominently thickened esophageal wall with strictures, whereas nonscirrhous-type carcinoma demonstrated thickening of the esophageal wall without strictures. Microscopically, all patients had lymph node metastases and lymphatic invasion. Blood vessel invasion was found in seven patients and extranodal invasion was found in seven. The prognosis of patients with both types of carcinoma was extremely poor. Only two patients who underwent curative surgery as well as chemoradiotherapy survived for more than 1 year. Therefore, further morphological studies on the early stages of diffusely infiltrating esophageal carcinoma should be performed. New treatment strategies such as intensive preoperative chemoradiotherapy based on sensitivity tests in individual patients will be required for treating the advanced stages of this disease.

Effect of Surgery on Neutrophil Leukotriene B4 Generation and Arachidonic Acid Content

The effect of surgery on neutrophil leukotriene B4 (LTB4) generation and arachidonic acid content was examined in 9 patients undergoing major surgery for esophageal cancer and 10 patients undergoing lesser surgery. Plasma IL-8 and neutrophil LTB4 generation was increased significantly 6 h after surgery regardless of the extent of surgery. This finding was associated with a decrease in neutrophil arachidonate content. In patients who underwent major surgery, neutrophil LTB4 generation decreased progressively on the 1st, 2nd, and 4th postoperative days, and this decrease paralleled a further decrease in neutrophil arachidonate content. These findings suggest that neutrophils are activated by surgery, thereby consuming their arachidonic acid, and that neutrophil LTB4 generation is influenced by postoperative arachidonate levels.