Akio Wakabayashi

Thoracoscopic en bloc total esophagectomy with radical mediastinal lymphadenectomy

OBJECTIVE Total esophagectomy with en bloc mediastinal lymphadenectomy for cancer carries a substantial morbidity and mortality rate. To investigate the feasibility of thoracoscopic technique, we carried out an extensive laboratory study. Encouraged by our excellent results, we conducted a clinical trial. METHODS From September 1994 to September 1995, 39 patients thoracic esophageal cancer lesions not invading surrounding organs underwent total esophagectomy with mediastinal lymphadenectomy by means of thoracoscopy. Ages ranged from 47 to 86 years. The procedures were conventional except for the thoracic portion, which was performed as a thoracoscopic procedure with six trocar holes instead of thoracotomy. All harvested lymph nodes were counted for each station. Spirometric data and plethysmographically determined vital capacity were measured before and after operation for all patients. RESULTS All procedures were accomplished as scheduled, and none was converted to open thoracotomy. The operating time was 200 +/- 41 minutes (mean +/- standard deviation). Estimated blood loss was 270 +/- 157 ml. The harvested lymph nodes numbered 19.7 +/- 11.1 per patient. Seventeen patients (45%) had positive lymph nodes. There were no in-hospital deaths within 30 days. Twenty-two patients did not require postoperative ventilatory support. Vital capacity decreased to 85% +/- 11% of the preoperative values, and forced expiratory volume in 1 second decreased to 82% +/- 16%. CONCLUSIONS Thoracoscopic mediastinal lymphadenectomy is technically feasible, and its completeness is comparable to that of the open technique. The decline in pulmonary function is significantly less than that seen in our previous experience with the open technique.

Thoracoscopic laser pneumoplasty in the treatment of diffuse bullous emphysema.

BACKGROUND Thoracoscopic laser pneumoplasty in the treatment of diffuse bullous emphysema by means of a contact neodymium:yttrium-aluminum garnet laser was evaluated by a retrospective analysis of the first consecutive 500 procedures in 443 patients. The indication for thoracoscopic laser pneumoplasty was intractable dyspnea. METHODS Advanced age (mean age, 67 years), high oxygen dependency (70%), steroid use (46%), and markedly diminished physical capacity (2% bedridden and 27% wheelchair-bound) were noted. Thoracoscopic laser pneumoplasty was carried out under general anesthesia and one-lung ventilation. Type 3 bullae (381 procedures) were contracted by contact neodymium:yttrium-aluminum garnet laser and type 4 bullae (199 procedures) excised. The operative mortality rate was 4.8%. RESULTS Subjective improvement was reported by 87% of the patients. Follow-up functional evaluation was available in 229 patients, which showed highly significant improvement. A comparison of preoperative and postoperative functional tests between type 3 and 4 bullae patients showed no significant difference, except the latter had higher decrease in airway resistance, residual volume, and total lung capacity. CONCLUSIONS Thoracoscopic laser pneumoplasty is an effective treatment for both type 3 and 4 bullous emphysema with an acceptable risk.

Thoracoscopic technique for management of giant bullous lung disease.

Giant bullae of the lungs are readily recognizable on plain chest x-ray films and are rare. Only 17 of more than 500 cases of thoracoscopic treatment of bullous lung disease over the past 3 years involved giant bullae, which included both types 1 and 4. Type 1 bullae have smooth internal lining without trabeculae and type 4 have trabeculae. The indications were dyspnea in 10 cases, spontaneous pneumothorax in 6, and infection in 1. The mean age of the patients was 55 years. Five patients were oxygen dependent, 1 was wheelchair-bound, and 3 were steroid dependent. Preoperative spirometry was available in 1 patient with type 1 bullae (forced vital capacity = 95% and forced expiratory volume in 1 second = 55% of the predicted values) and in 10 patients with type 4 bullae (forced vital capacity = 46.90% +/- 15.29% and forced expiratory volume in 1 second = 23.50% +/- 7.46% of the predicted values). Under general anesthesia with one-lung ventilation, the giant bullae were excised, plicated, or contracted by the laser, depending on the type, by means of thoracoscopy. Thoracoscopic surgery was successful in all patients, and no procedure was converted to thoracotomy. The duration of anesthesia was 4.44 +/- 1.49 hours, postoperative ventilatory support 42.24 +/- 64.22 hours, and postoperative air leaks 14.59 +/- 14.11 days. All patients did very well and pain was minimal. There was no recurrence for up to 3 years of follow-up. In conclusion, thoracoscopic treatment of giant bullae of the lungs is an effective alternative to conventional thoracotomy with minimal morbidity.

In Vivo Determination of Renal Tissue Oxygenation During Pulsatile and Nonpulsatile Left Heart Bypass

Abstract Data favoring pulsatile over nonpulsatile left heart bypass are conflicting. To study this problem, renal cortical and medullary tissue oxygen availability (O 2 a) and total renal oxygen flow were compared with total renal oxygen consumption during four hours of pulsatile and nonpulsatile bypass in dogs. Although there was no difference in renal tissue O 2 a during the first two hours, thereafter the decrease in renal O 2 a was greater during nonpulsatile bypass; total renal blood flow was greater with pulsatile bypass, and at the given renal oxygen flow, renal oxygen consumption was greater during pulsatile bypass. These data, along with previous work, support the superiority of pulsatile bypass.

Heparinless left heart bypass for resection of thoracic aortic aneurysms

Our clinical experience employing heparinless left heart bypass for the resection of twenty-three thoracic aneurysms is presented. In our current technic of heparinless left heart bypass, plastic tubing coated with nonthrombogenic polyurethane-polyvinyl-graphite material and a conventional roller pump are employed. The reduced size of the aneurysm below the aortic clamp during bypass facilitates careful dissection of the aneurysm and the aorta. Twenty-two of twenty-three patients underwent successful thoracic aneurysmectomy with this technic. None had subsequent paraplegia and the postoperative blood loss was minimal. Heparinless left heart bypass is a simple and safe procedure to facilitate thoracic aneurysm resection.

CONTINUOUS PERCUTANEOUS MONITORING OF MUSCLE pH AND OXYGEN PRESSURE

Newly developed all solid state catheter oxygen pressure (PO2) and pH electrodes were evaluated in dogs in respiratory acidosis and hemorrhagic shock. The electrodes were inserted into the blood vessels and thigh muscle by a percutaneous puncture technique. In animals with respiratory acidosis, arterial, venous, and intramuscular pH decreased in parallel as arterial carbon dioxide pressure (PCO2) increased. During severe acidosis, arterial and venous PO2 did not change appreciably, but intramuscular PO2 decreased moderately, indicating decreased tissue perfusion. In animals with hemorrhagic shock, intramuscular PO2 decreased in proportion to the blood loss, whereas the reduction in intramuscular pH and blood pressure lagged behind blood loss. A similar finding was observed during reinfusion of shed blood in surviving animals. In the animals that died, intramuscular PO2 AND PH remained low after the reinfusion of all shed blood, although arterial blood pressure did return to base line levels.

Left ventricular bypass: A new nonthrombogenic device with homograft aortic valves☆

Abstract A new pulsatile disposable nonthrombogenic left ventricular bypass unit is described. Plastic cannulas and tubing of the unit are coated with tetrahydrofuran-graphite-polyurethane-polyvinyl solution. The pump and valve housings are lined with Dacron® velour. The blood pump is energized with compressed oxygen. Two dog homograft valves are used as pump valves. In vitro tests have shown that this assist system has automatic regulation over output, that is, the output increases when systemic blood pressure falls or left atrial pressure rises. A systolic to diastolic ratio of 1:4 was optimal for the pumping cycle. A pumping rate of 70 beats/min gave the maximal output. The minute output of the pump can be regulated by changing either the pumping rate or the gas pressure. In vivo tests with normal dogs showed that they could tolerate near total left ventricular bypass for 30 hours with no evidence of clotting even though heparin was not used. Dogs subjected to acute heart failure and then treated with our nonthrombogenic left heart bypass unit for 10 hours showed a remarkable increase in survival over control animals. The elimination of heparin during bypass greatly reduced blood loss and, in turn, mortality. When near total bypass of the left ventricle occurred, the dogs heart was found to synchronize itself with a fixed pumping rate. An explanation for this phenomenon is postulated. This new nonthrombogenic left ventricular bypass system is simple in design and effective in performance.

Effect of Hypothermic Anoxic Cardioplegia on Myocardial Contractility

A study was undertaken to ascertain the protective effect of topical hypothermia on the anoxic heart. The presence or absence of myocardial damage was judged by myocardial contractility. The papillary muscle of an excised rabbit heart was detached from the mitral annulus and interposed between a fixed point and a force/displacement transducer. The maximal net developed tension (TNmax) of the papillary muscle with normothermic coronary perfusion was used as an index of myocardial contractility. With each temperature drop of 10 degrees C, the anoxia time that resulted in the same recovery level of TNmax was prolonged by a factor of 2.8. A nomogram was constructed correlating percent of myocardial recovery seen with different degrees of myocardial hypothermia during various anoxic periods. Optimum protection was noted at a myocardial temperature of 18 degrees C.

Experimental study of total body washout employing extracorporeal circulation and hypothermia

Abstract Total body washout was evaluated in dogs. The body temperature was cooled to 24 °C (muscle temperature) by extracorporeal circulation employing peripheral cannulation, and the animals were then exsanguinated. Cold lactated Ringers solution was perfused into the artery until hematocrit fell to 0.1 per cent while venous return was freely drained and discarded. Rewarming extracorporeal circulation using fresh homologous blood completed the procedure. Three groups of animals of six each were studied. In group I animals (control) with total body washout only, all survived. The animals in group II received lethal doses of pentobarbital sodium prior to total body washout. Plasma barbiturate levels were reduced from 13.1 to 2.6 mg/100 ml (= therapeutic level) after total body washout. Four animals who failed to survive after total body washout had blood pressures below 30 mm Hg prior to treatment, whereas the blood pressure of two survivors never fell below 40 mm Hg. Group III dogs with jaundice secondary to ligation of the common bile duct were treated with total body washout. All survived. Serum bilirubin levels fell from 6.7 to 0.5 mg/100 ml, a clearance rate of 91.6 per cent. This study indicates that total body washout is safe and effective in removing plasma-bound toxic substances. It should be initiated before an irreversible shock state appears.

Anatomic segmental resection of the lung by thoracoscopy: An experimental study

In patients who are unable to undergo a lobectomy for a small peripheral lung cancer, a partial thoracoscopic resection appears to be one viable alternative. However, since the regional lymphatics are disrupted in an anatomical fashion with a segmentectomy, it appears superior to a wedge resection. This experimental study was conducted to determine whether or not an anatomical segmental resection is feasible by thoracoscopy. A segmental resection of porcine lungs was performed using thoracoscopy. The segmental vessels were divided between ligatures. The segmental bronchus was divided by an endoscopic stapler. The intersegmental lung parenchyma was divided using a cotton dissector and a contact neodymium-yttrium aluminum garnet laser. Forty-three pigs were divided into seven groups as follows. Group 1: S1+2; group 2: S3; group 3: upper division; group 4: lower division; group 5: S6; group 6: S8; and group 7: S9+10. The operating times ranged from 145±15 min to 191±47 min. Blood loss ranged from 36±35 ml to 151±48 ml in all groups. The blood loss in the group with a resection of S6 and S9+10 was significantly greater than that of the other five groups. Most of the blood loss occurred during the division between the intersegmental planes. In conclusion, a thoracoscopic segmentectomy is considered to be technically feasible; however, further fefinements in this technique are warranted before beginning clinical trials.