Detection of Norovirus in Swab Specimens of Restrooms and Kitchens Collected for Investigation of Suspected Food Poisoning Outbreaks in Tokyo

During 2015-2016, we examined norovirus (NoV) RNA in swab specimens collected for investigation of suspected food poisoning outbreaks in Tokyo by real-time RT-PCR. Of 1,726 swab samples, 65 (3.8%) were NoV-positive and all positive swab samples were derived from NoV-positive outbreaks. Swab specimens were positive in 41 of 181 (22.7%) NoV outbreaks, while no positive swabs were detected in NoV-negative outbreaks. PCR fragments amplified from 32 swabs were sequenced, and all of them displayed complete homology with sequences from clinical and food samples. Though the results of swabs may be useful for determining the causative agent and infection route in some outbreaks, there was no case in which the results of swabs alone could elucidate the cause of food poisoning. Swabs may be useful in food poisoning investigations, if the results are interpreted in conjunction with epidemiological findings and clinical data. Swab samples are often collected several days after an outbreak, and the influence of disinfection should be taken into consideration. In NoV outbreaks, 55 out of 640 (8.6%) restroom swab specimens were NoV-positive whereas six of 618 (1.0%) were positive among kitchen swab specimens. In the restroom, the toilet bowl (43.6%) showed the highest positive rate and next was the toilet seat (14.5%). Additionally, NoV was detected at various sites in the restroom, including doorknob and floor. Since NoV-positive swab specimens may suggest that sanitation management is not performed properly in the facility, swab results may be utilized as a basis for hygiene guidance.

[Serial Food Poisoning Outbreaks Caused by Norovirus-Contaminated Shredded Dried Laver Seaweed Provided at School Lunch, Tokyo, 2017]

In February 2017, four food poisoning outbreaks occurred in Tokyo, involving ten schools. Shredded dried laver seaweed processed by a single food manufacturer in December 2016 was provided in common for the school meals that caused all four outbreaks. Of 4,209 persons exposed, 1,193 (28.3%) had symptoms of gastroenteritis. Norovirus (NoV) GII was detected in 207 (78.1%) of 265 cases by real-time RT-PCR. Thirty-one shredded dried laver seaweed samples were examined and seven (22.6%) of them were positive for NoV GII. PCR fragments of NoV ORF1/2 junction region (302 bp) from seven shredded dried laver seaweed samples and 20 clinical samples derived from the four outbreaks were sequenced. All of them displayed complete homology, and the genotype was classified as GII.17. A nearly full-length sequence (7,420 bp) of NoV RNA derived from a case was obtained by next-generation sequencer analysis and phylogenetic analysis indicated that this strain belongs to the same cluster as Hu/GII/JP/2015/GII.P17_GII.17/Kawasaki308. Thus, our investigation elucidated that the causative agent of these four serial food poisoning outbreaks was NoV GII.17 and the infectious source was a single batch of shredded dried laver seaweed. The water activity of the shredded dried laver seaweed was found to be 0.119 to 0.129. It was epidemiologically clarified that NoV does not lose infectivity for about two months even in the dry state. We conclude that a large diffuse outbreak of food poisoning caused by NoV GII.17 contamination of shredded dried laver seaweed had occurred in Tokyo. Our elucidation of the causative agent indicated that the food poisoning outbreaks in multiple areas of Japan, including Tokyo, during January to February 2017 were caused by the same contaminated food.

[Intraoperative indirect monitoring of electrocardiogram]

The electrocardiogram (ECG) is used as a standard monitoring method during anesthesia and operation. But during the operation of severely burnt patients, the electrodes for ECG cannot be placed on the ideal points for the standard limb leads. We tried the indirect monitoring of the ECG. We placed the electrodes on the sheet over the operating table, and connected the patient and the electrodes with water. By this way the ECG similar to the standard limb leads could be recorded. This method is useful for the patients, with such diseases as severe burn, severe atopic dermatitis and epidermolysis bullosa hereditaria.

[Amrinone (50 micrograms.kg-1.min-1) does not impair regional myocardial tissue metabolism during the 40%-decrease of left anterior descending coronary flow]

We investigated the effects of amrinone on metabolism of regional myocardial tissue during the 40%-decrease of left anterior descending coronary (LAD) flow in anesthetized dogs. Fourteen adult mongrel dogs weighing 15.4 +/- 5.1 kg were anesthetized with 0.5% isoflurane in 50% oxygen and ventilated mechanically to maintain normocapnia. After thoracotomy, regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode inserted in the myocardium. Electromagnetic blood flow probes were placed around LAD and circumflex artery. A 23-gauge catheter was inserted into a coronary vein which runs along LAD to obtain coronary venous blood for measuring oxygen content, lactate and pyruvate. A variable constrictor was placed distal to the flow-probe. After decreasing LAD flow for 40%, cardiac index (CI) decreased. Systemic venous resistance was decreased and CI was increased by amrinone (50 micrograms.kg-1.min-1) infusion. Myocardial tissue oxygen tension, venous lactate, lactate extraction, lactate-pyruvate ratio and excess lactate were all unchanged by amrinone. In conclusion, amrinone does not impair myocardial aerobic metabolism and increases CI under the stenosis of coronary artery.

[Effects of arterial carbon dioxide (PaCO2 not equal to 60 mmHg) on regional myocardial tissue oxygen tension and metabolism]

We investigated the effects of increased arterial carbon dioxide (PaCO2 not equal to 60 mmHg) on myocardial tissue oxygen tension and metabolism in anesthetized dogs. Ten adult mongrel dogs weighing 15.3 +/- 4.1 kg were anesthetized with 0.5% isoflurane in 50% oxygen and ventilated mechanically to maintain normocapnia. After thoracotomy, regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode inserted in the myocardium. Electromagnetic blood flow probes were applied on the left anterior descending artery and the circumflex artery. A 23-gauge catheter was inserted into a coronary vein to obtain coronary venous blood for measuring oxygen content, lactate and pyruvate. After control normocapnic ventilation, hypercapnia (PaCO2 62.7 +/- 3.2 mmHg) was induced by adding 10% carbon dioxide to the inspired gas for 20 minutes. As a result, the coronary blood flow and myocardial oxygen tension increased during hypercapnia. The myocardial lactate extraction and coronary venous lactate were unchanged and excess lactate was kept below zero, although coronary venous L/P ratio increased during hypercapnia. These results indicate that hypercapnia (PaCO2 not equal to 60 mmHg) increases coronary blood flow and myocardial oxygen tension, while myocardial aerobic metabolism is not impaired under hypercapnia.

[Evaluation of oxygen insufflation to non-ventilated lung during one-lung anesthesia]

To prevent hypoxemia during one-lung anesthesia, we have devised an oxygen insufflation machine which can insufflate oxygen (0.2-10 l.min-1) and apply CPAP (0-30 cmH2O) selectively to the non-ventilated lung. In all the 8 patients, arterial oxygen tension was maintained above 100 mmHg by using this machine, and was increased significantly from 76.2 +/- 11.2 mmHg (mean +/- SD) during one-lung anesthesia to 118.9 +/- 25.2 mmHg during the use of this machine. In conclusion, the machine prevents hypoxemia effectively during one-lung anesthesia without hindering surgical manipulations.

[Myocardial metabolism, oxygen demand and oxygen supply during prostaglandin E1 induced hypotension]

The effects of hypotensive anesthesia induced by PGE1 on myocardial metabolism, oxygen demand and oxygen supply were studied. Nine mongrel dogs were anesthetized with pentobarbital and isoflurane. Mean blood pressure (MBP), cardiac output (CO), blood gases (BG), coronary blood flow (CBF), and myocardial tissue oxygen tension (MPO) were measured. Arterial and coronary venous lactate and pyruvate concentrations were also measured. We calculated myocardial oxygen consumption, L/P ratio, excess lactate, oxygen extraction ratio and lactate extraction ratio to estimate the adequacy of myocardial aerobic metabolism. CO and CBF decreased in accordance with MBP depression. Myocardial oxygen consumption decreased significantly with PGE1 administration. Lactate and pyruvate concentrations, L/P ratio, excess lactate and myocardial tissue oxygen tension were unchanged. These results suggest that PGE1 exerts no significant effect on myocardial metabolism during hypotensive anesthesia.

[The effects of adenosine-induced hypotension on myocardial metabolism]

The effects of hypotension induced by adenosine on myocardial metabolism were studied in ten mongrel dogs anesthetized with 0.5% isoflurane. Adenosine was infused intravenously to reduce mean arterial blood pressure by approximately 30% during a period of 20 min. Although heart rate was unchanged, cardiac output increased and coronary blood flow increased 3-fold of the preinfusion value. Oxygen tension of the myocardium, and oxygen extraction as well as lactate extraction of the myocardium decreased. Myocardial oxygen uptake and myocardial lactate uptake were unchanged, but lactate production was observed in three of ten dogs. In addition, coronary venous lactate/pyruvate ratio and excess lactate increased, and excess lactate became positive in five of ten dogs. The results suggest that adenosine-induced hypotension may inhibit the myocardial aerobic metabolism.

[Effect of 10% carbon dioxide on regional myocardial tissue oxygen tension and myocardial metabolism]

We investigated the effects of arterial carbon dioxide tension on myocardial blood flow, tissue oxygen tension and metabolism in the anesthetized dogs. Eighteen adult mongrel dogs weighing 13.4 +/- 3.6 kg were anesthetized with 0.5% isoflurane, intubated and ventilated mechanically with 50% oxygen to maintain normocapnia. Endtidal CO2 fraction (FECO2) was monitored continuously by capnograph. Regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode inserted to the myocardium. Electromagnetic blood flow probes were applied on the left anterior descending artery and circumflex artery. For cardiac venous blood sampling, a 23G intravenous catheter was inserted into the cardiac veins (great coronary veins) carefully. After normocapnic ventilation, hypocapnia was induced by increasing the respiratory rate, and hypercapnia was induced by adding 10% carbon dioxide to the inspired gas. The coronary blood flow and myocardial tissue oxygen tension increased during hypercapnia and the myocardial lactate extraction decreased, while excess lactate and cardiac venous L/P ratio increased during hypercapnia. These results indicate that hypercapnia increase coronary flow and myocardial tissue oxygen tension but myocardial aerobic metabolism is impaired during hypercapnia.

[Comparison of standard-dose epinephrine and high-dose epinephrine in cardiopulmonary arrest outside the hospital]

We compared high-dose epinephrine (HDE) with standard-dose epinephrine (SDE) in improving the outcome of resuscitation after out-of-hospital cardiopulmonary arrest. The SDE group received epinephrine 1mg, and the HDE group received epinephrine 5mg respectively every 5 minutes until the return of spontaneous circulation. There were no significant differences between the SDE group and the HDE group in the rate of return of spontaneous circulation, rate of successful resuscitation and neurologic outcome. However, the rate of successful resuscitation tended to be higher in the SDE group. The ineffectiveness of HDE was considered to be due to the existence coronary artery diseases in the majority of patients, or increase in myocardial oxygen demand by the beta 1-adrenergic effects of epinephrine.

Effects of adenosine triphosphate (ATP) on somatosensory evoked potentials in humans anesthetized with isoflurane and nitrous oxide

In order to examine the usefulness of adenosine triphosphate (ATP) as an adjuvant to anesthesia for surgery requiring intraoperative somatosensory evoked potential (SSEP) monitoring, we have studied the effects of ATP on SSEPs in patients anesthetized with isoflurane and nitrous oxide (N2O). A control recording of SSEP was performed while anesthesia was maintained with 0.5% end-tidal concentration of isoflurane in 60% N2O. The recordings were repeated after an ATP infusion had been added to this basal anesthesia at the rates of 100 micrograms.kg bw-1.min-1 and 200 micrograms.kg bw-1.min-1. SSEP was also studied when end-tidal isoflurane concentration was increased to 1.5% after cessation of ATP infusion. An infusion of ATP combined with 0.5% isoflurane and 60% N2O effectively inhibited an increase in blood pressure during surgery. The amplitude of the cortical component of SSEP was lowered by 1.5% isoflurane, which also increased both cortical and spinal latencies as well as central conduction time (CCT). In contrast ATP infusions at both rates induced no significant changes in latencies, amplitude and CCT. The results indicate that ATP infusion combined with 0.5% isoflurane in 60% N2O can be a useful anesthetic technique for intraoperative SSEP monitoring because adequate anesthetic depth can be maintained by a low concentration of anesthetics without further suppression of SSEPs.

Effects of continuous negative extrathoracic pressure ventilation on left ventricular dimensions and hemodynamics in dogs

It has been reported that continuous negative extrathoracic pressure ventilation (CNETPV) depresses cardiac output less than continuous positive pressure ventilation (CPPV) does, and this difference may be related to the different effects of two ventilatory modes on preload. We performed simultaneous measurements of hemodynamics and left ventricular short axis dimensions by transesophageal echocardiography (TEE) to evaluate left ventricular preload and function during CNETPV and CPPV in normal dogs. Hemodynamic measurements and simultaneous TEE recording were performed at 5 successive periods; 1) the first control period of intermittent positive pressure ventilation (IPPV1), 2) CNETPV with negative end-expiratory pressure (NEEP) of -10 cmH2O (CNET10), 3) CNETPV with NEEP of -15 cmH2O (CNET15), 4) the second control period of IPPV (IPPV2), and 5) CPPV with PEEP of 15 cmH2O (CPPV15). Left ventricular end-systolic and end-diastolic dimension (LVESD and LVEDD), ejection fraction (EF) and fractional shortening (FS) were measured from TEE recordings. Both CNET10 and CNET15 induced no significant changes in hemodynamics and left ventricular dimensions, compared with those during IPPV1. However, CPPV15 reduced cardiac output and stroke volume (SV) and increased heart rate significantly, compared with IPPV2. CPPV15 significantly decreased LVEDD compared with IPPV2. Neither EF nor FS showed any significant change throughout the experiment. These results indicate that CNETPV preserved cardiac output because it maintained the preload and the left ventricular function.

[Effect of hypotensive anesthesia on tissue oxygen tension of the heart, kidney and liver]

The effects of hypotensive anesthesia by prostaglandin E1 (PGE1: 8 dogs) or trimetaphan (TMP: 8 dogs) on tissue oxygenation were studied in 16 mongrel dogs anesthetized with pentobarbital. Mean blood pressure (MBP), heart rate (HR), cardiac output (CO), blood gases (BG), the blood flow and tissue oxygen tension of the heart, the kidney and the liver were measured. The blood flow and oxygen tension were measured by electromagnetic flowmeters and by polarographic oxygen electrodes respectively. PGE1 or TMP was injected intravenously to decrease MBP by 30%. MBP, CO, HR and BG of PGE1 were not significantly different with those of TMP. Coronary blood flow decreased for 12% with PGE1 and for 33% with TMP. Though blood flows of the renal and the hepatic arteries were well maintained with PGE1, they decreased for 36% and 34% respectively with TMP. Oxygen tensions of the myocardium (both outer and inner layers) and the liver were well maintained with PGE1. But with TMP, oxygen tension decreased for 23% in outer layer, for 16% in inner layer and for 31% in the liver. Oxygen tension of the kidney remained unchanged with PGE1 and TMP. The results suggest that PGE1 is more useful for the maintenance of the tissue oxygenation than TMP during hypotensive anesthesia.

Continuous negative extrathoracic pressure ventilation, lung water volume, and central blood volume. Studies in dogs with pulmonary edema induced by oleic acid

The effect of continuous positive-pressure ventilation (CPPV) on extravascular lung water volume has been investigated, but there is only one report which studied the effect of continuous negative extrathoracic pressure ventilation (CNETPV). The effect of CNETPV on central blood volume (CBV) has not been studied. Changes in intrathoracic pressure by CNETPV may alter lung water volume and CBV. In this study the effects of CNETPV on lung water volume and CBV were compared with those of intermittent positive-pressure ventilation (IPPV) and CPPV in dogs with pulmonary edema induced by oleic acid. Nine mongrel dogs were anesthetized and given oleic acid at 0.06 ml/kg intravenously to induce pulmonary edema; CNETPV was applied with a cuirass and a negative thoracic pressure ventilator (Kimura OKT-100) for 1 h. Extravascular lung water volume (as extravascular thermal volume [EVTV]) and CBV were estimated with the double-indicator dilution method using thermal-sodium; PEEP and continuous negative extrathoracic pressure were matched to produce the same increments in FRC. The EVTV increased during CNETPV but did not change during CPPV. The CBV decreased during CPPV but did not change during CNETPV. An increase of transmural pulmonary microvascular pressure was thought to be one of the reasons for the increase in EVTV with CNETPV.

[Effect of carbon dioxide (hypocapnia and hypercapnia) on regional myocardial tissue oxygen tension in dogs with coronary stenosis]

Carbon dioxide (CO2) has been well documented to act as a potent vasodilator of coronary vessels under normal conditions. But there is little data available on the effect of CO2 on the collateral perfusion of patients with coronary insufficiency. We studied the effects of CO2 on the myocardial tissue PO2 in anesthetized dogs with critical coronary stenosis. Twelve mongrel dogs were anesthetized with pentobarbital and ventilated with 100% O2 to maintain normocapnia. Electromagnetic blood flow (BF) probe was applied on the left anterior descending artery (LAD). Regional myocardial PO2 was measured at two different sites using two pairs of monopolar polarographic needle electrodes; one inserted in the epicardial (EPI) layer, and the other in the endocardial (ENDO) layer. These were placed in the regions supplied by LAD and circumflex. Following the baseline recording, critical stenosis of LAD was produced by adjusting a copper-wire clamp occluder until LADBF was reduced by 50%. After a stable normocapnic ventilation, hypocapnia was produced by hyperventilation. To induce hypercapnia, exogenous CO2 was added to the inspired gas stepwise until end-tidal CO2 fraction reached 10%. Hypocapnia resulted in a significant reduction in myocardial PO2 in both EPI and ENDO non-stenotic areas, while hypercapnia increased these PO2 values dose-dependently. After coronary stenosis, hypocapnia resulted in a small but significant reduction of PO2 in endocardial ischemic area. Hypercapnia did not induce any sign of reduced regional myocardial PO2 or evidence of regional or intramural "steal" phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of arterial carbon dioxide tension on regional myocardial tissue oxygen tension in the dog]

We investigated the effects of arterial carbon dioxide tension on the myocardial tissue oxygen tensions of subepicardium and subendocardium in the anesthetized dogs. The study was done in fourteen open-chest mongrel dogs, weighing 13 +/- 1 kg, anesthetized with sodium pentobarbital (30 mg.kg-1 iv), and mechanically ventilated with 100% oxygen to maintain normocapnia. End tidal CO2 fraction (FECO2) was monitored continuously by capnograph. Regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode. Two pairs of combined needle sensors were carefully inserted, one in the epicardial and the other in the endocardial layer of the beating heart. Electromagnetic blood flow probe was applied on the left anterior descending artery (LAD). After a stable normocapnic ventilation, hypocapnia was induced by increasing the respiratory rate, and this mechanical hyperventilation was kept fixed throughout the experiments. To induce hypercapnia, exogenous carbon dioxide was added to the inspired gas step-wise until FECO2 reached 10%. Hypocapnic hyperventilation (PaCO2: 22 mmHg) invariably resulted in a significant reduction of coronary blood flow (LADBF) and left ventricular myocardial tissue PO2 in both epicardial and endocardial layers, while addition of carbon dioxide to the inspired gas (hypercapnic hyperventilation) reversed the change by increased LADBF and arterial PaCO2 in a dose-dependent manner. These results indicate that injudicious and severe hypocapnic hyperventilation may induce impaired myocardial tissue perfusion and oxygenation although normal cardiac output and arterial blood oxygenation are maintained.

[CO diffusing capacity during continuous negative extra-thoracic pressure]

Eight healthy males were studied to compare CO diffusing capacity (DLCO) during spontaneous breathing with that during continuous negative extra-thoracic pressure (CNETP). Mean DLCO was 33.0 +/- 5.1 ml.min-1.mmHg-1 during spontaneous breathing and 33.5 +/- 4.5 ml.min-1.mmHg-1 during CNETP with an end-expiratory negative extra-thoracic pressure (EENETP) of -20 cmH2O, and there was no significant difference between them (P less than 0.05). Pulmonary capillary blood volume, which was measured only in a male, was 76.7 ml during spontaneous breathing and 80.5 ml during CNETP. This change dose not seem to be significant. The results suggest that the effect of pulmonary diffusing capacity changes during EENETP on improvement of oxygenation may not be significant.

[Is ventilatory anaerobic threshold useful for preoperative assessment?]

The anaerobic threshold (VAT), obtained by measurement of ventilatory volume and by expiratory gas analysis, and the anaerobic threshold (LAT), obtained directly from the lactic acid value in the blood, were compared and evaluated during exercise load in 25 patients with mitral valve disease. Exercise loading was performed with an ergometer using a multistep method of increases of 5 W (Group A, 11 cases) or 10 W (Group B, 14 cases) per minute. The oxygen uptake value at the points of 0.5 mmol.l-1 and 1.0 mmol.l-1 increase in the lactic acid values when compared with the starting values were designated as 0.5 LAT and 1.0 LAT. VAT was found in 4 of 11 (36%) patients in Group A and in 12 of 14 (86%) patients in Group B and the ratio obtained was significantly higher in Group B than in A. The 0.5 LAT values for Group A and B were 2.4 +/- 0.5 and 2.2 +/- 0.3, respectively. The 1.0 LAT values were 2.9 +/- 0.7 and 2.7 +/- 0.4, and among the two groups no significant difference was found concerning 0.5 LAT or 1.0 LAT. VAT was seen in 16 or 25 patients and the average VAT value of the 16 was roughly at the midpoint between the average values for 0.5 LAT and 1.0 LAT. Therefore in patients in which VAT was seen with the expiratory gas method, VAT and LAT values were basically equivalent. However, in Group A, VAT was seen in only 4 of 11 patients and it is a fact that it is difficult to find VAT without a suitable exercise load.

Placental transfer and effects of famotidine on neonates

The effect of famotidine on neonates was studied in 34 obstetric patients who underwent elective cesarean section. In the famotidine group, 20 mg of famotidine was intramuscularly injected at 60 min before induction of anesthesia, and 0.5 mg of atropine was injected at 30 min before induction. In the control group, only atropine was given. Ratio of famotidine concentration in the umbilical venous blood to that in the maternal venous blood was determined as 0.64 +/- 0.13 (mean +/- SD). No significant differences were noted in the Apgar scores, neonatal gastric acidity, and results of liver function tests between the two groups. No side effect, such as the development of gastrointestinal infections, was observed.

[The ventilatory response to CO2 during end-expiratory negative extra-thoracic pressure and PEEP]

The effects of end-expiratory negative extra-thoracic pressure (EENETP) and PEEP on the ventilatory response to CO2 were studied in seven healthy volunteers. The changes in functional residual capacity during EENETP -20 cmH2O and PEEP 5 cmH2O were 13.9 and 12.9 ml.kg-1, respectively. The slopes of CO2 response (minute ventilation/end-tidal CO2) during ZEEP, EENETP and PEEP were 0.913, 0.622, 0.693 l.min-1.mmHg-1, respectively. The slopes during EENETP and PEEP were significantly decreased. These results indicate that EENETP and PEEP could worsen the CO2 response in patients with respiratory failure, especially, with chronic obstructive pulmonary disease in which functional residual capacity is increased.

[Respiratory flow and chest wall motion during negative extrathoracic pressure ventilation in human volunteers]

Respiratory flow and chest wall motion during negative extrathoracic pressure ventilation (NETPV) were compared with those during spontaneous breathing in 8 healthy male volunteers. Chest wall motion was evaluated by separate measurement of the changes in the cross sectional area of rib cage and abdomen, using respiratory inductive plethysmograph. During NETPV, expiratory flow was characterized by a large peak and a rapid decline at the early expiratory phase. NETPV increased the relative contribution of rib cage motion to tidal ventilation, and induced the abdominal paradoxical movements at inspiration in two volunteers. These results indicate that NETPV augments rib cage motion rather than abdominal motion, and this altered mechanics of chest wall may change intrapulmonary distribution of inspired gas.

[Effects of negative extra-thoracic pressure ventilation on extravascular lung water volume and central blood volume in normal dogs]

In negative extra-thoracic pressure ventilation (NETPV), lung water volume and central blood volume (CBV) could increase because of increased venous return and intensified negative interstitial pressure. The effects of NETPV on the extravascular lung water and CBV were examined in ten normal dogs by the double-indicator method using Na and cold water. The lung water volume measured by the method (EVTV) was compared with the lung water volume measured by the gravimetric method (EVLW) in 17 dogs. EVTV did not show any significant change in any ventilation modes compared with IPPV. CBV decreased from 21.9 ml.kg-1 to 19.2 ml.kg-1 in CPPV compared with IPPV (P less than 0.05). EVTV correlated well (r = 0.91, P less than 0.001) with EVLW. In normal dogs, NETPV did not change the lung water volume and CBV. NETPV dogs do not seem to have any disadvantage in respect of lung water volume compared with conventional positive pressure ventilations.

[Effects of negative extra-thoracic pressure ventilation on respiratory system and hemodynamics in normal dogs]

The effects of negative extra-thoracic pressure ventilation (NETPV) on respiratory system and hemodynamics were examined in ten normal dogs. Changes of the parameters obtained during intermittent NETPV (INETPV), and NETPV with negative end-expiratory pressure (CNETPV) were compared with those during IPPV and CPPV. Animals' chests and upper abdomens were confined in an acryl box. In INETPV and CNETPV, the dogs were ventilated with the negative extra-thoracic pressure ventilator (Kimura, OKT-100). Positive and negative pressure ventilation was carefully matched for tidal volume and the increase in FRC obtained with PEEP and the end-expiratory negative extra-thoracic pressure (EENETP). EENETP of -11.6 cmH2O produced the same FRC change as PEEP of 10.6 cmH2O did. Gas exchanges did not differ in any modes. INETPV did not change any hemodynamic parameters without PAP. In CNETPV, heart rate increased, and CVP, cardiac index (CI) and stroke volume (SV) decreased significantly (P less than 0.05), but tmCVP and tmPCWP did not change. The decreases of CI and SV (100----89.1, 88.8%) in CNETPV were significantly smaller when compared with CPPV (100----78.8, 74.5%). In CPPV, meanBP, CVP, tmCVP, tmPCWP, CI, SV changed significantly. The mechanisms of the decrease of CI and SV by CNETPV seemed to be different from those by CPPV.

[A study on the utility of flumazenil for patients in the ICU]

Flumazenil, a specific antagonist of benzodiazepines, was administered to adult patients receiving treatment at ICU, and its utility to hasten recovery from sedation was evaluated in 40 patients and its usefulness for differential diagnosis of sedated conditions was also evaluated in 5 patients. The efficacy rate for recovery from sedation induced by benzodiazepines was 85.0%. Moreover, flumazenil was considered to be useful for differentiation of sedated conditions when causes were unknown. Depression of respiration improved in association with improvement of consciousness level. In some patients an elevation in blood pressure was also observed with improved consciousness.

Effects of continuous negative extrathoracic pressure ventilation on renal function and alpha-atrial natriuretic peptide in normal individuals

Continuous negative extrathoracic pressure ventilation (CNETPV) may induce atrial distention by augmenting venous return, resulting in the increased secretion of atrial natriuretic peptide (ANP) and natriuresis. To clarify this hypothesis, we investigated the effect of CNETPV on renal function and plasma ANP level. Nine male healthy volunteers were studied during three successive 60-minute periods under (1) spontaneous breathing, (2) CNETPV with continuous negative extrathoracic pressure of -10 cm H2O, and (3) spontaneous breathing again. Continuous negative extrathoracic pressure ventilation induced a transient increase in plasma ANP level, but changes in plasma ANP level were not statistically significant. Although there was no significant difference in urine volume and urinary sodium excretion among three successive periods, a slight but significant increase in creatinine clearance was noticed during CNETPV. These results indicate that CNETPV with continuous negative extrathoracic pressure of -10 cm H2O does not induce the major change in ANP secretion and renal function in normal subjects.

[The effect of hypocapnia and hypercapnia on myocardial oxygen tension in hemorrhaged dogs]

To investigate the effect of carbon dioxide on the myocardial oxygenation during hemorrhagic shock, myocardial oxygen tension and coronary flow were measured during normocapnia, hypocapnia and hypercapnia. Eight adult mongrel dogs were anesthetized with pentobarbital, intubated and ventilated mechanically with 100% oxygen to maintain normocapnia. Then their chest was opened. An electromagnetic blood flow probe was applied on the left anterior descending artery. Two pairs of combined polarographic needle electrodes were carefully inserted, one pair in the epicardial layer, and the other in the endocardial layer of the heart. The animals were progressively bled in increments of 35-40ml.kg-1 (body weight). Hypocapnia was produced by increasing respiratory rate, and then normocapnia and hypercapnia were induced by adding the exogenous carbon dioxide. Hypocapnia decreased the coronary flow, and myocardial oxygen tension in outer and inner layer. On the contrary, hypercapnia increased them. It is possible that hypocapnia may compromise the oxygenation of the myocardium during hemorrhagic shock.

[The effects of hypocapnia and hypercapnia on tissue surface PO2 in hemorrhaged dogs]

To investigate the effects of carbon dioxide on the local blood flow during hemorrhagic shock, the tissue surface PO2 of liver, kidney and femoral muscle was measured during normocapnia, hypocapnia and hypercapnia. Eight adult mongrel dogs were anesthetized with pentobarbital, intubated and ventilated mechanically with 100% oxygen to maintain normocapnia. After laparotomy, miniature clark-type polarographic oxygen electrodes were placed on the surface of the liver, kidney and femoral muscle. The animals were hemorrhaged via arterial catheter to a mean arterial blood pressure of 50mmHg. The hypocapnia was produced by increasing respiratory rate and the hypercapnia was induced by adding the exogenous carbon dioxide. Hypocapnia decreased the liver and kidney surface PO2, and increased the muscle surface PO2. On the contrary, hypercapnia increased the liver and kidney surface PO2 and decreased the muscle surface PO2. So, it is possible that hypocapnia may compromise the oxygenation of the liver and kidney in the hemorrhagic shock.

[Power spectral analysis of EEG during simple deep hypothermia under ether anesthesia]

Power spectral analysis of electroencephalogram was performed during simple deep hypothermia under ether anesthesia, compared with that during hypothermic cardiopulmonary bypass under morphine anesthesia. In ether anesthesia group, EEG isoelectricity developed at average esophageal temperature of 27.2 degrees C which is higher than the temperature previously reported. This remarkable depression of the EEG may be due to deep ether anesthesia, because severe hypotension episodes were not associated with this and no neurological complication was noticed post-operatively. In cardiopulmonary bypass group, EEG activity persisted throughout the procedures even at the lowest esophageal temperature reached of 22.3 degrees C. In ether anesthesia group, the temperature at which EEG activity reappeared correlated with the duration of circulatory arrest. During simple deep hypothermia under ether anesthesia, the EEG is not useful to detect brain ischemia during cooling period, because EEG activity was lost in the early course of cooling, but during rewarming period the EEG demonstrated depression of cerebral function due to total circulatory arrest.

[Bronchiectasis treated with negative extra-thoracic pressure ventilation]

A 25-year old man with 5-year history of bronchiectasis was admitted to the ICU complaining of severe shortness of breath. He had a respiratory rate of 40 to 50 breath/min. On 0.5 l/min of oxygen with nasal cannula, arterial blood pH was 7.39, Paco2 52.3 mmHg, Pao2 45.0 mmHg. Then, on 1 l/min of oxygen, Pao2 was unchanged, but Paco2 increased to 58 mmHg. As his consciousness was so clear, we applied to him the negative extra-thoracic pressure ventilator which was designed by the authors. Negative extra-thoracic pressure ventilation (NETPV) was maintained at a IMV rate of 30 breath/min, peak negative extra-thoracic pressure of -20 to -30 cmH2O, and an inspiratory/expiratory ratio of 1:2. During NETPV, his respiratory rate and oxygen consumption were decreased and Pao2 was increased compared with his spontaneous breathing. He made a recovery from dyspnea, especially, he was able to take a deep breath. When NETPV was applied to him, pulmonary artery and arterial catheterizations revealed that central venous pressure was slightly decreased, cardiac index unchanged or slightly decreased, heart rate, systemic blood pressure, and pulmonary arterial pressure unchanged compared with spontaneous breathing. The patient was able to read books and maintained communication in his voice with his family and the medical staff. After 3 days of the treatment with NETPV, a marked improvement was noted and the patient was discharged from the ICU. NETPV has the benefits as follows. First, it is very easy for both a patient and a doctor to assist his breathing because an endotracheal intubation is not necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of carbon dioxide (hypocapnia and hypercapnia) on tissue blood flow and oxygenation of liver, kidney and skeletal muscle in the dog]

We investigated the effects of carbon dioxide on the splanchnic visceral organs (liver and kidney) as well as skeletal muscle in the anesthetized dog. Thirty two adult mongrel dogs were anesthetized with sodium pentobarbital, intubated and ventilated mechanically with 100% oxygen to maintain normocapnia. After laparotomy, miniature Clark-type polarographic oxygen electrodes were placed on the surfaces of liver, kidney and rectus femoris muscle. Electromagnetic blood flow (BF) probes were also applied to hepatic artery (HA), portal vein (PV), left renal artery (RA) and left femoral artery (FA). After a stable normocapnic ventilation, the hypocapnia was produced by increasing respiratory rate, and the hypercapnia was induced by adding the exogenous carbon dioxide.

RESULTS

Hyperventilation resulted in a significant decrease in HABF, PVBF, liver surface PO2 and kidney surface PO2 in parallel with the decreased PaCO2, but these parameters increased dose dependently when the carbon dioxide was added to the inspired gas (hypercapnic hyperventilation). On the contrary, FABF and skeletal muscle surface PO2 increased by hypocapnia and decreased during hypercapnia. Neither PaCO2 or cardiac output showed any significant change during the entire experiment. Arterial PCO2 appears to exert significant effects on both splanchnic and skeletal muscle perfusion as well as corresponding changes in tissue oxygenations. It is possible that injudicious and prolonged hypocapnic hyperventilation may seriously compromise splanchnic organ perfusion and oxygenation.

[Evaluation of the performance of a negative extra-thoracic pressure ventilator (OKT-86)]

We evaluated the performance of a new negative extra-thoracic pressure ventilator (OKT-86, which was designed by the authors) applying it on ten patients with ASA Physical Status I (mean body weight: 54.4 +/- 12.1 kg) during anesthesia. Uneven distribution of negative extra-thoracic pressure was not observed within the chamber that a patient was wearing. Tidal volumes of more than 10ml.kg-1 were obtained at a respiratory rate of 10 or 16 breath.min-1 and a peak negative extra-thoracic pressure of -18 to -20 cmH2O. The values of delta FRC were 5.4 and 11.9 ml.kg-1 at continuous negative extra-thoracic pressure of -5 and -10 cmH2O, respectively, and these values were three times as those of the conventional cuirass ventilator. Consequently, sufficient tidal volumes and delta FRC were obtained using OKT-86.

[Periodic sublingual buprenorphine for pain relief after upper abdominal surgery]

Analgesic effects were evaluated in patients who received sublingual administration of buprenorphine (0.2mg ampule for injection) as programmed every 8 hours for 3 days following upper abdominal surgery. Patients who received periodic sublingual buprenorphine obtained satisfactory postoperative analgesia and also required less analgesics than those who never received periodic administration of analgesics. Approximately one half of patients who received periodic sublingual buprenorphine required no additional analgesics. Arterial blood-gas analysis showed a significant increase in carbon dioxide tension after sublingual buprenorphine. One patient revealed marked respiratory acidosis after sublingual buprenorphine. These results suggest that periodic sublingual buprenorphine makes up for slow onset in sublingual administration and that it is also effective, convenient, and safe for pain relief after upper abdominal surgery. We, however, should pay attention to the respiratory depression caused by sublingual buprenorphine.

A new closed-system using partially frozen injectate for thermodilution cardiac output determinations

The FI (partially frozen injectate) system, a new closed-system devised by the authors for thermodilution cardiac output determinations, has two major features: 1) it needs no ice-filled receptacle to keep injectate cold because it uses partially frozen injectate, and 2) it can go without monitoring the injectate temperatures during the whole process of cardiac output determinations. The author evaluated the accuracy and reproducibility of cardiac output determinations with the FI system in 10 critically ill patients, as compared with another closed-system (which is commercially available) and the standard open method. The injectate temperatures in the FI system were also measured in vitro. The mean injectate temperature in the FI system was 0.71 +/- 0.26 degrees C and 80% of the injectate temperatures were lower than 1.0 degrees C. Even when no monitoring of injectate temperatures was made, the predicated error in the calculated cardiac output resulted as low as 2% with the FI system. The mean cardiac output values were not statistically different between the FI system and the other two systems.

[Changes in serum pancreatic secretory trypsin inhibitor (PSTI) during and after heart surgery]

Serum pancreatic secretory trypsin inhibitor (PSTI) is considered to be one of the acute phase reactants which increase after tissue injuries like surgery or major trauma. 25 patients were studied to investigate the changes in serum PSTI during and after heart surgery. 18 patients underwent the operation with the aid of cardiopulmonary bypass (CPB)-CPB group, and the other 7 patients, all pediatric cases, were treated under simple deep hypothermia by surface cooling without CPB-simple hypothermia group. Serum amylase, serum C reactive protein (CRP), cardiac index and A-aDO2 after surgery were examined, and the duration of CPB or circulatory arrest were recorded. The correlation between serum level of PSTI after surgery and these parameters were also studied. During surgery, a transient elevation of serum PSTI was noticed in the period of CPB, but no significant change of serum PSTI was seen under simple deep hypothermia and circulatory arrest. On the first post operative day, a slight but significant increase of serum PSTI was seen in CPB group, on the other hand no significant increase was seen in simple hypothermia group. Postoperative increase of serum PSTI was correlated to circulatory arrest time in simple hypothermia group, and was inversely correlated to cardiac index determined immediately after the operation in CPB group. No correlation was seen between serum level of PSTI after surgery and serum amylase, CRP, A-aDO2 or duration of CPB. The magnitude of increase of serum PSTI after heart surgery was small, and did not seem to be well correlated to the extent of surgical insults.

Continuous intercostal nerve block for pain relief after lumbar incision

To relieve postoperative pain along a lumbar incision in 9 patients the intercostal nerves were blocked with catheters for continuous epidural anesthesia. The catheters were inserted near the intercostal nerves, above and beneath the incision, just before the wound was closed and 0.25% bupivacaine hydrochloride solution was infused periodically through the catheters. With this technique 5 of 9 patients had a satisfactory analgesic effect and could breathe deeply or cough without pain. The other 4 patients did not have satisfactory results and this was believed to be owing to inadequate insertion of the catheters. None of the patients had any complications. The technique is simple and can produce an analgesic effect repeatedly without causing pain for the patient.