MR Imaging of Anomalous Lobes of the Liver

Four patients with anomalous lobes of the liver were observed at MR imaging. In one patient the anterior segment of the right hepatic lobe was absent and in 3 patients the left hepatic lobe was anomalous. The hepatic vasculature supporting the information of the anomalous hepatic lobes was well observed in all patients.

Clinical significance of diffusion-weighted whole body magnetic resonance imaging with background body signal suppression (DWIBS) as a staging procedure for lymphoma patients in comparison with FDG-PET

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Background: FDG-PET is thought to be an important staging tool in lymphomas. However, high cost and exposure to radioactive agents are of disadvantage. Diffusion weighted whole body magnetic resonance imaging with background body signal suppression (DWIBS) is recently reported to be a new way of magnetic resonance imaging which can make FDG-PET-like imaging possible to detect tumors (Takahara et al; Radiation Medicine 22: 275–282, 2004). This study is aimed to compare accuracy and clinical significance of DWIBS to FDG - PET. Methods: We examined 19 lymphoma (Ly) patients (pts) by using both DWIBS and FDG -PET at the time of diagnosis before therapy. There were follicular Ly in 3 pts, nodal marginal zone Ly in 1, diffuse large B-cell Ly in 9 including primary stomach Ly in 2, peripheral T -cell Ly in 4, and MALT Ly of stomach (GI-MALT) in 2. DWIBS was performed with a 1.5 -Tesla system as previously reported (Ochiai et al; Nichidoku -Iho 50: 86–98, 2005). Clinical staging was made according to the Ann Arbor classification. Results: Both DWIBS and FDG -PET had positive findings in 18 of 19 pts except for a case of GI -MALT. In nodal lesions, DWIBS was positive in 16 pts at 66 sites compared to 16 pts at 68 sites with FDG -PET. DWIBS was negative in 3 pts at 5 sites in spleen, hilar and mediastinal lymphnodes where positive in FDG -PET. DWIBS was positive in 2 pts at 4 sites in iliac and inguinal lymphnodes that are negative in FDG -PET. In extranodal lesions, DWIBS was positive in 12 pts at 17 sites as compared to 12 pts at 18 sites with FDG -PET. Involvement of bone and stomach were equally identified at 8 sites. DWIBS was negative in 2 pts at 2 sites in liver and pleura with FDG -PET positive. Small skin lesions were clearly identified on DWIBS. Discordance of clinical staging was not observed between DWIBS and FDG -PET. Conclusions: Although some discrepancy was seen between DWIBS and FDG -PET, there was no disadvantage of DWIBS compared to FDG -PET. Furthermore, DWIBS has no risk of radiation exposure and is even advantageous to detect lesions with FDG -PET negative. We conclude DWIBS is a new useful tool to assess tumor spread in lymphomas.

No significant financial relationships to disclose.

Prognostic significance of dihydropyrimidine dehydrogenase expression in breast cancer

We have investigated dihydropyrimidine dehydrogenase expression as a prognostic marker in breast cancer. A total of 119 women with breast cancer undergoing surgery between 1985 and 1996 were included in this study. Eighty-seven patients were treated with postoperative chemotherapy including 5-fluorouracil or 5-fluorouracil derivatives. Fifty-nine (50%) of 119 patients were determined to be immunostaining-positive for dihydropyrimidine dehydrogenase. There was no significant difference between dihydropyrimidine dehydrogenase staining and tumour size, lymph node status, clinical stage, oestrogen receptor status, histologic grade, or 5-fluorouracil administration. When evaluated in patients treated with 5-fluorouracil or 5-fluorouracil derivatives, patients with dihydropyrimidine dehydrogenase-positive tumours had a significantly (P<0.05) poorer disease-free survival compared to those with dihydropyrimidine dehydrogenase-negative tumour. No conclusion can be drawn about the prognostic impact of dihydropyrimidine dehydrogenase status in patients who were not treated with 5-fluorouracil regimes due to the small number of such cases in this series. Lymph node and dihydropyrimidine dehydrogenase status were independent prognostic factors for disease-free survival, and lymph node status for overall survival using multivariate analysis. In conclusion, dihydropyrimidine dehydrogenase is a possible prognostic factor in patients with breast cancer treated with 5-fluorouracil or 5-fluorouracil derivatives.

A comparative study of subcutaneous mastectomy with radical mastectomy

The purpose of this study was to compare the results of 133 cases (131 patients) of subcutaneous mastectomy with axillary dissection between 1983 and 1999 and 910 cases of radical mastectomy during the same period. The median follow-up period of the subcutaneous mastectomy group and the radical mastectomy group were 66 months and 81 months, respectively. The age at operation was significantly (p<0.01) younger in the subcutaneous mastectomy group than in the radical mastectomy group and the clinical stage was significantly (p<0.01) earlier. Lymph node metastasis was significantly (p<0.01) higher in the radical mastectomy than in the subcutaneous mastectomy group. There was no difference in ER status between the two groups. There was local recurrence in 5 (3.8%) members of the subcutaneous mastectomy group and in 12 (1.3%) members of the radical mastectomy group. There was no difference in disease-free survival and overall survival between the two groups. Divided into two subgroups by lymph node status, there was no difference in disease-free survival and overall survival between the two groups. Local recurrence occurred more frequently (p<0.05) in the subcutaneous mastectomy group, however, than in the radical mastectomy group when no lymph node metastasis was found. Multivariate analysis using the Cox hazard model showed that operation method and lymph node status were independent prognostic factors for local recurrence, whereas, lymph node status and ER status were independent prognostic factors of disease-free survival. In conclusion, subcutaneous mastectomy presents a risk factor for local recurrence, but the survival rate of the subcutaneous mastectomy group is as favourable as the radical mastectomy group.

[Changes of vascular reactivity following esophagectomy measured by near-infrared spectroscopy]

We examined the alterations of peripheral vascular responses following ischemic insult during perioperative period of esophagectomy. Increase of palm blood flow after vascular occlusion, i.e., reactive hyperemia (RH), measured by near-infrared spectroscopy (NIRS) was employed to assess forearm vascular responses. The measurements of RH were performed in esophagectomized patients (n = 12) before induction of anesthesia and postoperatively until the next day of extubation in comparison with normal volunteers (n = 11). After esophagectomy, the RH, which was comparable with those in volunteers, was depressed by 50% on 1 POD, and did not recover until the third POD. In particular, patients receiving laparoscopy-assisted surgery showed less decrease of RH than those receiving the standard open laparotomy. These results suggest that vascular responses to increase blood flow against ischemic insult is depressed following esophagectomy.

Hemodynamic effects of milrinone during weaning from cardiopulmonary bypass: comparison of patients with a low and high prebypass cardiac index

OBJECTIVE

To compare the hemodynamic effects of milrinone during weaning from cardiopulmonary bypass (CPB) in patients with a low pre-CPB cardiac index (CI) <2.5 L/min/m2) and in patients with a high pre-CPB CI (> or =2.5 L/min/m2).

DESIGN

Prospective, randomized, double-blind study.

SETTING

University hospital.

PARTICIPANTS

Forty-eight patients scheduled for elective coronary artery bypass graft surgery.

INTERVENTION

Patients were divided into 4 groups: (1) low pre-CPB CI/placebo, (2) low pre-CPB CI/milrinone, (3) high pre-CPB CI/placebo, and (4) high pre-CPB CI/milrinone. Patients received a loading dose of 20 microg/kg of milrinone followed by an infusion of 0.2 microg/kg/min or placebo 15 minutes before the anticipated weaning time.

MEASUREMENTS AND MAIN RESULTS

In the low pre-CPB CI/ placebo group, low CIs and high systemic vascular resistances (SVRs) were observed after CPB. High doses of dopamine and dobutamine were needed, and infusion of epinephrine was used in 5 of the 12 patients for hemodynamic support. Milrinone improved CI and reduced SVR in the low pre-CPB CI/milrinone group. Norepinephrine was needed to maintain an adequate systemic blood pressure in 6 of the 12 patients, however. In the high pre-CPB CI/placebo group, satisfactory CIs and SVRs were observed during weaning from CPB with low doses of dopamine and dobutamine. Milrinone significantly increased CI and decreased SVR in the high pre-CPB CI/milrinone group: 10 of the 12 patients had CIs above the upper limit of normal, and 7 patients had SVRs below the lower limit of normal.

CONCLUSION

Milrinone was effective during weaning from CPB in patients with a low pre-CPB CI. Milrinone in combination with norepinephrine was a good alternative to epinephrine for the treatment of myocardial dysfunction after CPB.

[Anesthetic management for endoscopic surgery in two patients with goiter]

We report anesthetic experience of two patients for endoscopic removal of thyroid tumor by new surgical approach. A subplatysmal air pocket, which had been created by using a subcutaneous dissector, was maintained by insufflating carbon dioxide (CO2) at an insufflation pressure of 6 mmHg. In one patient, the arterial CO2 pressure increased from 29 mmHg to 44 mmHg, and in another patient from 31 mmHg to 36 mmHg. We did not experience any symptoms of sustained CO2 absorption such as severe hypercarbia, acidosis, and massive subcutaneous emphysema. The patients were discharged on the fifth and the fourth postoperative day with no complications. The advantages of this endoscopic surgery include little postoperative pain, quick recovery, and short hospital stay after operation. However, possible occurrence of intraoperative hypercarbia during endoscopic surgery must be considered, and continuous monitoring of ventilation by end-tidal CO2 or arterial CO2 pressure is mandatory.

[Anesthetic management of a patient with latex allergy diagnosed preoperatively]

Since the first report in 1979, the number of patients with latex allergy has progressively increased. We experienced an anesthetic management of a 3 year-old child who underwent the repair of anal atresia. The first operation was performed in newborn period. After the surgery, the patient developed skin rash and the loss of consciousness every time anal irrigation was made with latex-containing catheter. Latex-allergy was diagnosed at the age of 3 years, with the positive skin test by latex extract. It took enormous time and efforts to find out the possibility of latex-contamination in a wide variety of medical equipments and supplies to prevent allergic reaction during perioperative period. In this patient, perioperative cause was uneventful. It is suggested that preoperative preparation is essential and caution should be also paid to prevent allergic reaction in daily life.

Hypermagnesemia-induced cardiopulmonary arrest before induction of anesthesia for emergency cesarean section

We describe a 42-yr-old woman scheduled for emergency cesarean section who had sudden cardiopulmonary arrest just before induction of general anesthesia. Hypermagnesemia, caused by accidental overdose of magnesium sulfate during transportation to the operating room, was the primary cause of this life-threatening event. Anesthetic management after such events and a brief summary of the literature regarding iatrogenic hypermagnesemia in obsteric patients are provided.

Doxapram accentuates white matter injury in neonatal rats following bilateral carotid artery occlusion

The effect of the respiratory stimulant, doxapram, on white matter damage was investigated in neonatal rats under cerebral ischemia. Five-day-old rats underwent bilateral carotid artery occlusion with or without 50 mg/kg i.p. of doxapram. Their brains were neuropathologically examined 48 h later. Doxapram induced about a 20% decrease of PCO(2) for 90 min, but did not cause any neuropathological abnormalities. Bilateral carotid artery occlusion resulted in mild cerebrocortical lesions in 67% of pups, and white matter lesions in the internal capsule in 44%. Doxapram, in addition to bilateral carotid artery occlusion, produced more severe white matter injury in the internal capsule (injury score; 0.67+/-0.87 vs. 1.70+/-0.48, P<0.05) and in the subcortical white matter (0.33+/-0. 67 vs. 1.10+/-0.54, P<0.05). These results demonstrated that the use of doxapram under an ischemic condition accentuates white matter damage in neonatal rats.

The relationship between modified pulse wave transit time and cardiovascular changes in isoflurane anesthetized dogs

OBJECTIVE

To clarify the relationship between blood pressure and pulse wave transit time at the peripheral artery from the R wave of the electrocardiogram (m-PWTT), the effects of cardiovascular interventions on this relationship was evaluated.

METHODS

Ten mongrel dogs were anesthetized by isoflurane inhalation, and catheter tip pressure transducers were inserted into the ascending aorta and at the bifurcation of abdominal aorta to measure central and peripheral pulse wave arrival. Pulse wave arrival at the ascending aorta from the R wave represents pre-ejection period (PEP) and pulse wave arrival between the ascending aorta and bifurcation of aorta represents pulse wave transit time (PWTT), thus m-PWTT = PEP + PWTT. Hypertension was induced by the continuous infusion of dobutamine and phenylephrine, and hypotension was induced by deepening isoflurane anesthesia, acute blood loss and nitroglycerine infusion. The relationship between timing components (PWTT, PEP, and m-PWTT) and blood pressure was recorded and analyzed by using the least squares method.

RESULTS

The relationship between timing components (PWTT, PEP and, m-PWTT) and blood pressure was significant and highly correlated. When the change in blood pressure was due to the myocardial contractility, such as after dobutamine infusion, the relationship between all timing components and blood pressure was consistent and negative. However, when the change in blood pressure was due to the vasoactive agents, such as phenylephrine, the relationship between timing components and blood pressure was dependent on the reflex change in PEP.

CONCLUSIONS

Change in m-PWTT is a good parameter to predict blood pressure changes, although the absolute blood pressure value cannot be obtained.

Leucocyte distribution during sevoflurane anaesthesia

We have examined if sevoflurane anaesthesia per se modified the number of circulating leucocytes in humans. Fifty-nine patients undergoing elective surgery were anaesthetized with sevoflurane in oxygen. The inhaled concentration was increased gradually to 5% and maintained for 20 min. Arterial blood samples were obtained before induction of anaesthesia and at 20 min. While the total number of leucocytes remained constant, circulating neutrophils decreased (mean 3370 (SD 1030) mm-3 to 3170 (940) mm-3; P < 0.01) and lymphocytes increased (1870 (520) mm-3 to 2040 (580) mm-3; P < 0.01). We conclude that high concentrations of sevoflurane modified the distribution of leucocytes in anaesthetized patients.

[High-resolution CT of otosclerosis]

High-resolution CT (HRCT) scans of thirty-two patients (60 ears) with the clinical diagnosis of fenestral otosclerosis were evaluated retrospectively. HRCT was performed with 1-mm-thick targeted sections and 1-mm (36 ears) or 0.5-mm (10 ears) intervals in the semiaxial projection. Seven patients (14 ears) underwent helical scanning with a 1-mm slice thickness and 1-mm/sec table speed. Forty-five ears (75%) were found to have one or more otospongiotic or otosclerotic foci on HRCT. In most instances (30 ears), the otospongiotic foci were found in the region of the fissula ante fenestram. No significant correlations between CT findings and air conduction threshold were observed. We found a significant relationship between lesions of the labrinthine capsule and sensorineural hearing loss. We conclude that HRCT is a valuable modality for diagnosing otosclerosis, especially when otospongiotic focus is detected.

[Minimally invasive technique for mitral valve repair--the importance of intraoperative transesophageal echocardiography]

A 65-year-old male with mitral regurgitation was scheduled for the mitral valve repair by means of minimally invasive technique. The technique, which requires a 10-cm right parasternal incision, offers minimal discomfort, less postoperative pain, quick functional recovery and excellent cosmetic healing. However, the intraoperative monitoring by the transesophageal echocardiography was required to evaluate the mitral valve function and to confirm the complete removal of air from the apex of the left ventricle and right upper pulmonary vein due to the small operative field. In addition, the monitoring of the short-axis view of the left ventricle makes it possible to evaluate and to confirm the preload and the left ventricular contractility. We considered that the transesophageal echocardiography is essential and useful for the minimally invasive mitral valve repair.

[Preventive use of diltiazem to suppress supraventricular tachyarrhythmia in the patients after esophagectomy]

We investigated the efficacy of preventive use of diltiazem to suppress supraventricular tachyarrhythmia such as paroxysmal atrial tachycardia (PAT) and atrial fibrillation (Af) in the patients who underwent transthoracic esophagectomy. We divided 52 patients into 2 groups; the diltiazem group (n = 26) and the control group (n = 26). In the diltiazem group continuous intravenous infusion of diltiazem (1-3mcg.kg-1.min-1) was started when the patient's heart rate remained over 110.min-1 without any predisposing factor. On the other hand, in the control group we did not use it preventively. In both groups, we did not restrict the use of antiarrhythmic agents if necessary. We recognized PAT or Af in the control group (54%) more often than in the diltiazem group (19%). PAT or Af seldom occurred after the 4th post-operative day in the both groups. Serum diltiazem concentrations of 9 patients after about 10 hours infusion showed great variation (between 30 and 250 ng.ml-1). In 7 of them the diltiazem concentration increased as the duration of infusion was prolonged. However, we did not observe bradyarrhythmia. We consider that the continuous diltiazem infusion is effective in suppressing supraventricular tachyarrhythmia after esophagectomy.

[The effect of cerebral perfusion pressure on cerebral blood flow in the rhesus monkey during sevoflurane anesthesia]

The effect of cerebral perfusion pressure on cerebral blood flow (CBF) was studied under the normocapnic condition in the rhesus monkey under sevoflurane anesthesia. CBF was measured by means of positron emission tomography technique. After the measurement of CBF at 0.5% sevoflurane as control, the measurement was repeated at 2.0% sevoflurane (1 MAC), when blood pressure was kept at a half of the control value. The measurement was also repeated at the same sevoflurane concentration, when the mean blood pressure was restored with the infusion of angiotensin II. Average CBF as well as regional CBFs were compared between two different mean blood pressures at 2.0% sevoflurane. Average CBF increased significantly (+35%), when the mean arterial pressure was increased by the angiotensin II infusion. All the regional CBFs except at frontal cortex increased significantly (+ about 30%) in response to the increase in the mean arterial pressure. The increase in occipital CBF was greatest (+52%). We conclude that CBF during sevoflurane anesthesia up to 2.0% might become dependent on the cerebral perfusion pressure, indicating the compromised autoregulation of CBF in the rhesus monkey.

[The effect of sevoflurane on regional cerebral metabolism and cerebral blood flow in rhesus monkeys]

The effects of sevoflurane on cerebral metabolism and hemodynamics were studied in rhesus monkeys. Cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMR O2) as well as their regional changes were measured by means of positron emission tomography technique. After the measurement of regional CBFs and CMR O2s at 1.5% sevoflurane as control, the measurement was repeated at 3.0% sevoflurane and at the same sevoflurane concentration with the infusion of angiotensin II to restore mean arterial pressure. Regional CBFs and CMR O2s were compared among three different conditions. At 3.0% sevoflurane, regional CBFs increased significantly in response to the increase in the mean arterial pressure, suggesting the inhibition of autoregulation of CBF. However, regional CBF/CMR O2 ratio was not significantly different among the cerebral regions with each condition. It could be concluded that CBF during sevoflurane anesthesia up to 3.0% might become dependent on the cerebral perfusion pressure and the changes in regional CBFs varied among the regions. On the other hand, the ratio of oxygen consumption and delivery was well maintained throughout the brain regions.

[The effect of droperidol and sevoflurane on serotonin-induced bronchoconstriction in dog]

Serotonin is a potent bronchoconstrictor, but the site of bronchoconstriction has not been determined. The present study was performed in dogs to clarify the site of bronchoconstriction induced by serotonin as well as to clarify the bronchodilating effect of droperidol and sevoflurance on the serotonin-induced bronchoconstriction by means of deflation flow-volume curve (DFVC) method, passive expiratory flow volume curve (PEFVC) method and respiratory system impedance measurement by forced oscillation method. Infusion of serotonin (60 micrograms.kg-1.min-1) induced a significant decrease in maximal expiratory flow at 10% of maximal expiratory volume (DEF10) by DFVC method and a significant increase in respiratory system impedance (Z). After droperidol (0.1 mg.kg-1) injection, DEF10 and Z returned to the control level and they remained unchanged even after the termination of serotonin infusion. Respiratory system compliance and resistance by PEFVC were unchanged by both serotonin and droperidol infusion or sevoflurane. Inhalation of 5% sevoflurane during serotonin infusion caused no significant change in DEF10. These findings indicate that serotonin-induced bronchoconstriction involves the small airway as well as the large airway. It is suggested that droperidol reversed serotonin-induced small airway constriction probably due to the antagonism of serotonin receptor in the airway. Bronchodilating effect of sevoflurane is probably limited in the small airway constricted by serotonin.

[Effects of nitrous oxide on electroencephalographic activity during sevoflurane anesthesia: a zero-crossing analysis]

We have investigated the influence of nitrous oxide (N2O) on central nervous system (CNS) during sevoflurane anesthesia by using zero-crossing method of EEG in 31 patients. The study was divided into three parts: Study 1 (n = 18), Study 2 (n = 6) and Study 3 (n = 7). (Study 1) After induction of anesthesia, sevoflurane 1.0 % in oxygen (O2), and sevoflurane 1.0 % with 67 % N2O in O2 were given to the patients sequentially in a random fashion, and EEG was recorded. (Study 2) Sevoflurane 1.7 % in O2, and sevoflurane 0.7 % with 67 % N2O in O2, which were considered to be the same anesthetic depth (= sevoflurane 1 MAC), were inhaled, and EEG was recorded in the same manner as in the study 1. (Study 3) We compared the effects of N2O on EEG during intravenous administration of fentanyl and midazolam with 67 % N2O, and without N2O, and EEG was recorded in the same manner. In all studies, percentage of each frequency range (delta, theta, alpha, beta) and average frequency were calculated by zero-crossing method. During sevoflurane anesthesia, the EEG activity was decelerated with N2O, depending on minimum alveolar concentration (MAC). But there were no significant changes in EEG activity of the patient with and those without N2O during intravenous anesthesia. We concluded that the influences of N2O on CNS can be evaluated by quantitative analysis of EEG.

[Air pollution by sevoflurane in operating room and serum and urine inorganic fluoride of anesthetists]

Since lower blood-gas partition coefficient of sevoflurane provides rapid induction and emergence from anesthesia, sevoflurane has been used widely for inhalational anesthesia. However, because higher minimum alveolar concentration of sevoflurane requires a large dosage of anesthetic than other volatile anesthetics, air pollution with sevoflurane in the operating room might be of great concern. Anesthetists may keep inhaling the low concentration of anesthetics every day, even though scavenging system is equipped in the operating room. The purpose of this study is to evaluate the effects on anesthetists of the low concentration of anesthetics by measuring the inorganic fluoride concentration in the urine and serum of anesthetists and operating room nurses. Healthy 29 anesthesiologists and two operating room nurses were studied. Informed consent was obtained. Inorganic fluoride ions in the serum and urine were measured. Simultaneously sevoflurane concentration in operating room was measured in three operating rooms, at two places in the corridor and in the recovery room. Sevoflurane concentrations in three operating rooms were 1.22 ppm, 2.13 ppm and 6.05 ppm respectively. Concentration in the recovery room was 0.544 ppm. Serum and urine concentrations of inorganic fluoride were 1.1 +/- 0.1 mumol.l-1 and 36.2 +/- 17.1 mumol.l-1, respectively (mean +/- SD). Serum concentration of inorganic fluoride was within normal ranges. Although it is possible that fluoride concentration in urine is influenced by urine volume and a half of fluoride deposits in bone, no abnormal values in urine were found in this study. These results suggest that long term exposure to low concentration of sevoflurane and isoflurane causes no significant increase in their metabolites in operating room staffs.

[A case of massive hemorrhage associated with the removal of longstanding intrabronchial foreign body]

A 46 year old male patient was admitted with fever and cough. A chest X-ray film revealed a foreign body shadow of a denture fragment in the right intermediate bronchus that he had swallowed one year and half ago. Rigid bronchoscopy was used to remove the foreign body under general anesthesia. During the procedure, massive hemorrhage occurred from bronchus, and the foreign body was not removed successfully and the patient sustained near cardiac arrest. Postoperatively, he recovered from the near fatal condition with support of mechanical ventilation in ICU for several days. After one month, pulmonary angiography was performed and it revealed the transfiguration of pulmonary artery and other vessels close to the foreign body. Granular tissue around the foreign body was observed by preoperative bronchoscopy. Disruption of such vessels and granular tissue by rigid and forced fiberscopy was suspected to have caused the massive bleeding. Later, the denture fragment was successfully removed by right thoracotomy. We should take this complication into consideration and preoperative fiberoptic bronchoscopy and pulmonary angiography may be beneficial to the anesthetic management of such patients.

[Changes of peripheral airways through mechanical ventilation in acute respiratory failure]

To evaluate the morphologic changes in the peripheral airways associated with positive pressure ventilation, fine fiberoptic bronchoscopy (1.8 mm outer diameter) was performed in 12 patients who had no history of prior pulmonary failure. In 19 examinations, the main morphologic findings were paleness and bronchial dilatation in the peripheral airways where increased secretions, pigmentation and stenosis or collapse were also observed. Patients with bronchial dilatation had longer periods of mechanical ventilation (17 +/- 8 days) compared to those without dilation (10 +/- 5 days). The structural destruction in the peripheral airways observed in patients on prolonged positive pressure mechanical ventilation suggests that barotrauma may be more widespread than previously recognized.

MR imaging of anomalous lobes of the liver

Four patients with anomalous lobes of the liver were observed at MR imaging. In one patient the anterior segment of the right hepatic lobe was absent and in 3 patients the left hepatic lobe was anomalous. The hepatic vasculature supporting the information of the anomalous hepatic lobes was well observed in all patients.

[The effects of anesthetic techniques and insufflating gases on ventilation during laparoscopy]

The present study was performed to clarify the influences of anesthetic methods and insufflating gases on arterial blood gas and ventilation during laparoscopy. Forty five women undergoing laparoscopy for gynecological procedure were studied after dividing into four groups; general anesthesia with control ventilation or epidural anesthesia with spontaneous breathing, plus insufflation with carbon dioxide (CO2) or nitrous oxide (N2O). After CO2 insufflation, PaCO2 increased significantly in the patients who were mechanically ventilated, but not in the patients breathing spontaneously. After N2O insufflation, the decrease in tidal volume (VT) and the increase in VD/VT were significant, but minute ventilation was well maintained by the compensatory increase in respiratory frequency during spontaneous breathing. On the other hand, after CO2 insufflation VE and VD/VT increased significantly without any change in VT. PaO2 decreased significantly after both insufflation and Trendelenburg tilt in all groups, probably secondary to the decrease in functional residual capacity. These findings suggest that during laparoscopy, ventilation could be well maintained by spontaneous breathing, although the increase in VD/VT and costal breathing indicate the increase in respiratory work load. We recommend that ventilation and oxygenation should be closely monitored during laparoscopy to avoid hypercapnia and hypoxia.

Ectasis and pallor of peripheral airways during mechanical ventilation

STUDY OBJECTIVE

To evaluate morphologic changes in peripheral airways associated with positive-pressure ventilation (PPV).

DESIGN

Single-blind study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Ten patients who required mechanical ventilation due to acute respiratory failure but had no history of prior pulmonary disease.

INTERVENTIONS

Seventeen fiberoptic bronchoscopy procedures were performed using a fine fiberoptic bronchoscope of 1.8 mm outside diameter.

MEASUREMENTS AND MAIN RESULTS

The main morphologic findings were pallor and ectasis. Increased secretions, pigmentation, and stenosis or collapse in peripheral airways also were observed. Patients with ectasis were more likely to have had prolonged mechanical ventilation (17 +/- 9 days) as compared with those patients without ectasis (9 +/- 5 days).

CONCLUSION

The structural alterations in peripheral airways noted in patients on prolonged PPV suggest that barotrauma may be more widespread than previously recognized.

Contribution of rib cage and abdominal movement to ventilation for successful weaning from mechanical ventilation

In order to test the hypothesis whether the breathing pattern is helpful in predicting weaning outcome in patients being weaned from mechanical ventilation, 38 patients who underwent operation for esophageal cancer were evaluated at weaning from mechanical ventilation (19 unsuccessful weanings, group U, and 19 successful weanings in age-matched patients, group S). Since all patients initially fulfilled our weaning criteria, ventilatory parameters such as tidal volume, respiratory frequency, minute ventilation, and arterial blood gas analysis showed no significant differences between the groups. The breathing pattern was registered quantitatively by means of respiratory inductive plethysmography at 3 cmH2O (0.3 kPa) of CPAP prior to weaning. The contribution of rib cage movement to tidal volume (%RC) was significantly greater in group U than in group S (P < 0.05). Indeed, 84% of the patients in group S showed %RC less than 50%, compared to only 16% of the patients in group U (P < 0.05). The results suggest that the breathing pattern is one important factor in predicting the outcome of weaning in patients after thoraco-abdominal surgery. Diaphragmatic fatigue is suspected to be the mechanism for the increase in the RC component in patients with unsuccessful weaning outcome.

[Quantitative analysis of electroencephalographic (EEG) activity during sevoflurane anesthesia]

The change in electroencephalographic (EEG) activity during sevoflurane anesthesia was quantitatively evaluated by using zero-crossing analysis in 10 adult patients. The deceleration of EEG activity was significant and dose-dependent. Such change was not significantly different among the regions. Burst suppression appeared at 2-2.5 MAC in all patients. The significant decrease in both alpha and beta activities and the significant increase in delta activity disappeared with 1% or less of sevoflurane. Toward the emergence from anesthesia, EEG activity accelerated and there was no significant difference in its activity between the emergence period and control period. The results demonstrated that the effect of sevoflurane on EEG activity is similar to that of other inhalation anesthetics, but the difference among anesthetics should be clarified in a further study.

Evaluation of gastric tube with esophageal thermister (Thermosump)

The accuracy and the feasibility of esophageal temperature measured by a new gastric tube. Thermosump, which is incorporated with a esophageal thermister, was evaluated in anesthetized dogs (n = 6) and men (n = 59). In dogs, esophageal temperature measured by Thermosump was correlated well with the temperatures measured by the conventional esophageal thermister, and also by the pulmonary artery catheter (r = 0.98, 0.98, respectively). In anesthetized men, correlation between esophageal temperature by Thermosump and rectal, or bladder temperature was good during surgery of extremities (r = 0.81, 0.80, respectively). But during abdominal surgery, correlation between esophageal and bladder temperature was relatively poor (r = 0.50). Insertion of the tube, and suction of gastric fluid through the tube were easy without any complication. This newly developed gastric tube with a esophageal thermister was safe, and useful for measuring esophageal temperature.

Serum and urinary inorganic fluoride concentrations after prolonged inhalation of sevoflurane in humans

Serum and urinary concentrations of inorganic fluoride were measured before and after sevoflurane anesthesia in 10 patients without renal disease, who were scheduled for surgery lasting 13.4 +/- 0.9 h (mean +/- SE). The mean concentration of serum inorganic fluoride reached a maximal value of 42.5 +/- 4.5 mumol/L at the end of anesthesia. However, 5 of 10 patients had serum inorganic fluoride concentrations that exceeded 50 mumol/L (i.e., the nephrotoxic dose). A positive correlation was found between serum inorganic fluoride concentration and anesthetic dose. The largest urinary excretion of inorganic fluoride was 1804 +/- 378 mumol/day in the first postoperative day and rapidly decreased thereafter. We concluded that lengthy sevoflurane anesthesia created serum inorganic fluoride concentrations that could influence renal function, although nephrotoxicity was not demonstrated in our biochemical study.

[Electroencephalographic change during induction of high-dose fentanyl anesthesia--evaluation by LIFESCAN EEG monitor]

The relation between the patient's consciousness level and the change in electroencephalographic (EEG) activity during general anesthesia has not been well understood. In the present study, we evaluated such relationship quantitatively during the induction of high-dose fentanyl anesthesia in adult open-heart cases. There are significant increase in delta activity and significant decrease in alpha and beta activity in response to the induction of anesthesia. The loss of consciousness coincided with the sharp reduction in delta ratio and edge frequency (80%). Such reduction was more prominent in delta ratio than in edge frequency. These findings suggest that delta ratio could indicate the consciousness level during the induction of high-dose fentanyl anesthesia. Further study is needed to clarify the EEG response during inhalation and intravenous anesthesia in relation to EEG activity.

Differential sensitivity to halothane anesthesia of the genioglossus, intercostals, and diaphragm in kittens

Recent studies in humans and animals have indicated that different inspiratory muscles have different sensitivities to respiratory depressants. The sensitivity of inspiratory muscles during early growth and development relative to that in adults of the same species, however, has not been studied. We therefore studied the activity of the diaphragm, the external intercostals, and the genioglossus by means of electromyography and its moving time average with different concentrations of halothane in seven 2-mo-old kittens. The kittens spontaneously breathed 1.0%-2.0% halothane in oxygen while PaCO2 was maintained at about 60 mm Hg by adding CO2 to the inspired gas as needed. Muscle activity was evaluated in terms of the peak height of the moving time average. Activity at 1% halothane was used as the control measurement because measurements at zero inspired concentrations of halothane could not be obtained without sedation, which is known to depress respiratory muscle activity. Halothane anesthesia significantly (P less than 0.01) decreased phasic inspiratory activity of the inspiratory muscles in a dose-dependent fashion. Genioglossal activity was completely abolished at 1.5% and 2.0% halothane. By contrast, in our previous study in adult cats under nearly identical experimental conditions, the phasic genioglossal activity was depressed but present even at 3.0% halothane. The degree of depression at 1.5% and 2.0% halothane was least in the crural diaphragm (71.8% +/- 5.8%, 66.6% +/- 4.5% of control, respectively), intermediate in the intercostals (68.9% +/- 9.6%, 35.4% +/- 8.8%), and greatest in the genioglossus (0.0%, 0.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Improved PCO 2 monitoring during high frequency jet ventilation

During high frequency jet ventilation (HFJV), it has been shown that Pa(CO)(2) can be predicted by capnography when the frequency was temporarily reduced to obtain a steady expiratory CO(2) tension (P et(CO)(2)). The influence of the sampling site of expiratory gas in the airway and the driving pressure of the ventilator on the difference between Pa(CO)(2) and P et(CO)(2) was investigated in ten adult patients who underwent general anesthesia. During HFJV (frequency: 100 bpm, inspiratory duty cycle; 30%), its frequency was temporarily reduced to 10 bpm in twelve different condition; i.e., 3 different driving pressures (Pd; 20, 30, and 40 psi) at 4 different sampling sites (d; 0, 2, 5, and 10 cm in the endotracheal tube). Both P et(CO)(2) and Pa(CO)(2) were measured simultaneously, and their difference was evaluated by using Student's t-test. The difference between Pa(CO)(2) and Pmax(CO)(2) (the maximum P(CO)(2) value in the airway during exhalation) was minimal, when Pd was greater than 30 psi, and d was greater than 5 cm. The present study suggests that better prediction of Pa(CO)(2) can be done by P et(CO)(2) during HFJV, when d and Pd were set as large as possible to obtain stable expiratory P(CO)(2) curve.

Sympathetic responses in out-of-hospital cardiac arrest

To determine the clinical relevance of the sympathetic response to out-of-hospital cardiac arrest, we measured plasma concentrations of catecholamine and cortisol in ten such arrested patients on their arrival. The duration of cardiac arrest was estimated from 9 to 200 min before basic life support was initiated by ambulance personnel. Two of the patients developed spontaneous pulses in response to ALS and were resuscitated, and the others were not, although the length and the extent of ALS were not different between the two groups. Plasma concentrations of epinephrine (EN), norepinephrine (NE) and cortisol prior to ALS in both groups were markedly elevated. In particular, the patients who never regained spontaneous pulses showed 58-fold and 12-fold increase in the plasma EN and NE levels, respectively, which were much higher than those in the resuscitated cases; 8- and 1.7-fold increase, respectively. These massive EN and NE discharges correlated well with the arrest time (r = 0.96 and 0.94, respectively) and the degree of acidosis (r = -0.82 and -0.82, respectively).