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Biomedical subjects

Y Okutsu

Publications and source records attributed to Y Okutsu.

At least 37 records · Page 2Linked to original sources
PubMed1991

[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.

Adult↗
PubMed1990

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.

Adult↗
PubMed1990

[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.

Adult↗
PubMed1990

[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.

Animals↗
PubMed1990

[The tidal volume, arterial blood gas and functional residual capacity changes during negative extra-thoracic pressure ventilation and positive airway pressure ventilation].

Eight patients, of ASA physical status I or II soon after total knee replacement under general anesthesia, were studied to compare negative extra-thoracic pressure ventilation (NETPV) with positive airway pressure ventilation (PAPV). The measured parameters during the two ventilatory modes were tidal volume, arterial blood gas and functional residual capacity change (delta FRC). Tidal volume obtained during NETPV was 60 to 80% of that during PAPV at the same absolute values of peak pressure. delta FRC obtained during NETPV was 30 to 40% of that during PAPV at the same absolute values of end-expiratory pressure. A decrease in the esophageal pressure was 4 to 11cmH2O at an end-expiratory negative extra-thoracic pressure of -10 to -20 cmH2O. When the patients were ventilated with the same values of minute ventilation on NETPV and PAPV, there was no significant difference in blood gas values. These findings suggest that efficiency of NETPV is less than that of PAPV at the same absolute working pressure but pulmonary gas exchange of NETPV is almost equal to that of PAPV at the same minute ventilation in the normal lung.

Aged↗
PubMed1990

[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.

Animals↗
PubMed1990

[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.

Animals↗
PubMed1989

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.

Journal Article↗
PubMed1989

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

UNLABELLED: 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.

Animals↗
PubMed1989

[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.

Animals↗
PubMed1989

[Which factors affect the liver function most after gastrectomy in the gastric cancer patients?].

We examined the factors which influence the postoperative liver function in the gastric cancer patients who received gastrectomy by a particular surgeon. One hundred and five patients had no history of liver diseases, no blood transfusions, and no infection after the operation. They also had normal liver function preoperatively. They were anesthetized with halothane-nitrous oxide oxygen or enflurane-nitrous oxide oxygen with epidural anesthesia by the same group of anesthesiologists. GOT was followed for one month after the operation to evaluate the liver function. In 44 patients, GOT went up to above 50 IU.l-1. The maximal GOT correlated with low hemoglobin level on the 1st postoperative day, the duration of hypotension below 80 mmHg of the systolic blood pressure, and duration of the operation. These results suggest that special attention should be paid to correct hemoglobin level and to avoid hypotension during anesthesia.

Adult↗
PubMed1989

[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.

Adult↗
PubMed1989

[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.

Abdomen↗
PubMed1989

[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.

Adult↗
PubMed1989

[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)

Adult↗
PubMed1989

[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.

Anesthesia↗