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Biomedical subjects

S Dohi

Publications and source records attributed to S Dohi.

At least 127 records · Page 7Linked to original sources
PubMed1994

Comparisons of tetracaine spinal anesthesia with clonidine or phenylephrine in normotensive and hypertensive humans.

To compare the hemodynamics and anesthetic effects of spinal tetracaine containing either clonidine or phenylephrine administered to normotensive or hypertensive patients, we studied 75 patients allocated to one of three groups, each of which included nine hypertensive patients: clonidine group (n = 25) received 2 mL of 0.5% tetracaine (10 mg) containing clonidine (0.15 mg); phenylephrine group (n = 25) received 2 mL of 0.5% tetracaine (10 mg) containing phenylephrine (3 mg); and control group (n = 25) received 2 mL of 0.5% tetracaine (10 mg) alone. Analgesic levels and the intensity of motor block obtained did not differ significantly among the three groups. However, the regression of sensory block (skin dermatome) was significantly slower in patients given clonidine (T9 +/- 3) or phenylephrine (T9 +/- 3) at 300 min after the injection than in those (L1 +/- 3) in the control group (P < 0.01). Between normotensive and hypertensive patients, there was no significant difference in sensory and motor block in the three groups. Mean blood pressure (MBP) in both hypertensive and normotensive patients given tetracaine-clonidine remained approximately 20% lower than that in the control group for as long as 7 h after the injection (P < 0.05). We conclude that the inclusion of clonidine can provide similar effects to that of phenylephrine with respect to prolongation of hyperbaric tetracaine spinal anesthesia, but could cause more hypotension, without bradycardia, in both normotensive and hypertensive patients for a prolonged time (i.e., 420 min).

Adult↗
PubMed1994

[Strategies of general anesthesia for cleft palate surgery in Cambodia].

Hare lip and cleft palate surgery team activities in Cambodia were launched in 1989 by a non-governmental Japanese organization, Operations Unies. The objectives of the project are to provide appropriate surgical treatment and safe general anesthesia for local patients and also to conduct technology transfer of general anesthesia and surgery to the local medical staffs. From June 1991 to January 1993, a surgery/anesthesia team was dispatched 4 times and a total of 130 patients received surgical treatments under general anesthesia. Anesthesia techniques employed included total intravenous anesthesia in 70 patients (54%) and intravenous anesthesia with 0.3-0.7% of halothane in 60 patients (46%). There were no major complications, such as airway obstruction and apnea, in the recovery room and in the ward. The reasons why we chose intravenous agents are difficulty in obtaining inhaled agents in Cambodia and lack of scavenging system in a operating room. Although halothane anesthesia with spontaneous breathing has been recommended in developing countries, total intravenous anesthesia could be one of the applicable techniques in these countries. In Cambodia, shortage of medical doctors and the absence of anesthesiologist constitute a major barrier to technology transfer in clinical anesthesia.

Anesthesia, General↗
PubMed1994

[The concentration effects of isoflurane-N2O anesthesia on cardiovascular responses to skin incision].

To investigate the concentration effects of isoflurane-nitrous oxide anesthesia on cardiovascular responses to skin incision, we studied 24 non-premedicated patients undergoing lower abdominal operation. Anesthesia was induced with inhalation of 70% nitrous oxide and isoflurane, and maintained with 70% nitrous oxide and three different concentrations of isoflurane (1.25, 1.6, 1.95 MAC). Blood pressure and heart rate were recorded continuously before and after skin incision. Because more than half the patients with 1.95 MAC became hypotensive with systolic blood pressure of less than 80 mmHg just before the skin incision, it was difficult to define the values of MAC BAR (blocking adrenergic responses) in the present study. Cardiovascular responses at skin incision were not completely suppressed at 1.6 MAC isoflurane-N2O anesthesia and no further blocking effects were obtained at 1.95 MAC isoflurane-N2O anesthesia. These results suggest that higher concentration of isoflurane does not guarantee stronger protective effects on stimulation like skin incision.

Abdomen↗
PubMed1994

[The effects of ephedrine and phenylephrine on arterial partial pressure of oxygen during one-lung ventilation].

We investigated the effects of ephedrine (EP) and phenylephrine (PH) on partial pressure of oxygen and intra-pulmonary shunt during one-lung ventilation under general anesthesia with enflurane, fentanyl and oxygen. When systolic blood pressure decreased to less than 80% of the resting values, 30 adult patients who were randomly assigned into 2 groups, received either EP 0.15 mg.kg-1 or PH 2 micrograms.kg-1. In group-EP, PaO2 increased significantly from 187 +/- 112 to 205 +/- 114 mmHg (FIO2 = 1.0, P < 0.05), while in group-PH, PaO2 changed from 209 +/- 129 to 248 +/- 84 mmHg without statistical significance. Intra-pulmonary shunts were essentially unchanged in both groups. Neither dysrhythmia, ST-T changes on electrocardiography, congestive heart failure, nor severe hypoxemia were observed in any patient during the study. These results indicate that EP and PH in above doses can be safely administered to treat arterial hypotension during one-lung ventilation.

Adult↗
PubMed1994

[A case of elevated serum creatine-kinase after anesthesia].

An elevation of creatine-kinase was noted postoperatively in a 50 year-old male who had cerebral aneurysm surgery under isoflurane, N2O and O2 anesthesia. Serum CK concentration reached as high as 5919 IU.l-1 immediately after surgery and elevation was associated with the temperature elevation of above 39.5 degrees C and port-wine urine. The postoperative course was uneventful and elevated serum creatine-kinase was corrected within next 6 days. Since elevated serum creatine-kinase is known to occur in acute stage of cerebrovascular accident, and since the influence of myocardial infarction, malignant hyperthermia and drugs could be neglected, we assumed that an abnormal elevation of CK values observed in the present patient resulted from stimulation of sympathetic nervous system due to cerebral bleeding and to hyperpermeability of sarcolemma of skeletal muscle.

Anesthesia, Inhalation↗
PubMed1993

Heterogeneity in the molecular species of heat-stable enterotoxin of Vibrio cholerae non-O1 expressed by Escherichia coli carrying the cloned toxin gene.

The biological activity of the heat-stable enterotoxin of Vibrio cholerae non-O1 (NAG-ST) was found to be predominantly associated with the periplasmic extract (about four-fold higher than the culture supernatant) of a recombinant E. coli (JM109) strain carrying the NAG-ST toxin gene. Four molecular species of NAG-ST, two each from the periplasmic extract and culture supernatant of JM109, were purified. Amino acid sequence analysis of the four NAG-ST peptides isolated by HPLC revealed that they all differed from that of the mature 17-amino acid residue NAG-ST released by V. cholerae non-O1. The M(r)-values of the peptides obtained from the periplasmic extract were 4331 and 2785, while those recovered from the culture supernatant were 3154 and 2785. It thus appears that V. cholerae NAG-ST is synthesized as larger molecules in the recombinant E. coli strain. The differences in sizes of the exported NAG-ST molecule could relate to differences in the enzyme cleavage system between E. coli and V. cholerae.

Amino Acid Sequence↗
PubMed1993

Transesophageal Doppler echocardiographic assessment of pulmonary venous flow pattern in subjects without cardiovascular disease.

This study was designed to assess pulmonary venous flow dynamics using transesophageal Doppler echocardiography. Under general anesthesia, we studied 54 surgical patients with no history or physical evidence of cardiac disorders. In all patients pulmonary venous flow was easily identified by transesophageal color flow mapping. Pulmonary venous flow pattern, which was obtained clearly in 85% (4654) of patients by transesophageal pulsed Doppler echocardiography, was tri- or quadriphasic. The first wave, which was often biphasic in elderly patients, occurred during ventricular systole (S wave). The second wave occurred in diastole during the early ventricular filling phase of mitral flow (D wave). The third wave was reverse flow toward the pulmonary vein during atrial contraction (A wave). The following variables were measured: the peak flow velocities of each wave (PFVs, PFVd, PFVa), and the ratio of PFVs to PFVd (PFV(S/D)). The PFVd correlated with age (r = -0.56, P < 0.001), indicating age-related decrease. The PFV(S/D) correlated with age (r = 0.61, p < 0.001), indicating age-related increase. These results would indicate that the contribution of pulmonary venous flow during diastole to total pulmonary venous flow decreases with age. Our data suggest that age-related diastolic dysfunction of the left ventricle would affect pulmonary venous flow dynamics and that left atrial storage volume during ventricular systole would increase with age.

Adolescent↗
PubMed1993

Halothane concentrations required to block the cardiovascular responses to incision (MAC CVR) in infants and children.

The purpose of this study was to determine the halothane concentration in N2O required to block the cardiovascular responses to skin incision (MAC CVR) in infants and children. We studied 64 unpremedicated ASA 1 infants and children (one month to seven years). In each infant or child, anaesthesia was induced slowly with halothane and N2O, and an endotracheal tube was placed. The MAC CVR was assessed, after a steady state end-tidal halothane concentration had been established for ten minutes, by the "up and down technique" of Dixon. Positive responses were defined as an increase in MAP or HR > 10%. The MAC CVR50 values of halothane with 60% N2O were 1.16 +/- 0.23% at 1-6 mo, 1.17 +/- 0.18% at 7-12 mo, 0.95 +/- 0.26% at 1-3 yr, and 1.12 +/- 0.16% at 4-7 yr. The value at 1-3 years children was less than those in the other age groups (P < 0.05). The changes of MAP were correlated with changes of both HR and pupillary diameter. These results indicate that the values of MAC CVR50 of halothane in infants and children are higher than those required to block motor responses (MAC). The halothane requirement to block cardiovascular responses is lowest in the children aged one to three years.

Adrenergic Fibers↗
PubMed1993

Lumbar epidural anaesthesia prevented prostaglandin E1-induced diuretic effect in enflurane anaesthetized patients.

Prostaglandin E1 (PGE1) is used to induce deliberate hypotension during anaesthesia. The purpose of this study was to compare the PGE1-induced diuretic effect in anaesthetized patients with and without lumbar epidural anaesthesia. The changes in haemodynamic variables, urinary flow, one-hour creatinine clearance (Ccr), and fractional excretion of sodium (FENa) during injection of PGE1 or a vehicle were compared in 42 surgical patients during enflurane anaesthesia with lumbar epidural anaesthesia (EPI group) with those in 44 surgical patients during enflurane anaesthesia alone (GA group). Patients in the GA group demonstrated increases in urinary flow (114 +/- 46%) (mean +/- SE), Ccr (74 +/- 26%), and FENa (54 +/- 23%) during PGE1 infusion, which were not observed in the patients in the EPI group. Mean arterial pressure decreased during PGE1 infusion from 92 +/- 3 to 70 +/- 2 mmHg in the GA group (P < 0.01) and from 85 +/- 2 to 65 +/- 1 mmHg in the EPI group (P < 0.01). Plasma antidiuretic hormone concentration during surgery was 12.5 +/- 2.6 U.L-1 in the GA group and 2.3 +/- 0.8 U.L-1 in the EPI group (P < 0.001). It is concluded that PGE1-induced diuresis was prevented by lumbar epidural anaesthesia.

Alprostadil↗
PubMed1993

Errors in the measurement of cardiac output by thermodilution.

Cardiac output (CO) determination by thermodilution, which was introduced by Fegler in 1954, has gained wide acceptance in clinical medicine and animal experiments because it has several advantages over other methods with respect to simplicity, accuracy, reproducibility, repeated measurements at short intervals, and because there is no need for blood withdrawal. However, errors in determination of CO by thermodilution may be introduced by technical factors and the patients' pathological conditions. The current review summarizes these issues and provides our recommendations, based on the medical literature published between 1954-1992. To obtain more reproducible and accurate CO values by thermodilution, one should make several determinations (1) by using 10 ml injectate at room temperature for adults and 0.15 ml.kg-1 injectate for infants and children; (2) at evenly spaced intervals of the ventilation cycle; (3) when rapid intravenous fluid administration is discontinued; (4) by observing thermodilution curves so that baseline pulmonary artery temperature drift or the existence of intra- and extracardiac shunts are noticed. Finally, CO determination by thermodilution may be unreliable or impossible in patients with low CO states and tricuspid or pulmonary regurgitation. Since non-invasive CO monitoring has not replaced CO determination by thermodilution, intimate knowledge of this method is crucial for anaesthetists to prevent errors in the management of patients.

Adult↗
PubMed1993

Coronary artery spasm with ventricular tachycardia after administration of methoxamine during cervical epidural anesthesia--a case report.

Coronary artery spasm occurred during thoracotomy under cervical epidural anesthesia in a 60-year-old male patient who had no prior history of myocardial ischemia. It is most likely that the administration of methoxamine induced the spasm. Hypotension and venodilatation induced by the epidural anesthesia and increased vagal tone might also contribute to the spasm.

Anesthesia, Epidural↗
PubMed1993

Assessment of enterotoxin production by Yersinia enterocolitica and identification of a novel heat-stable enterotoxin produced by a noninvasive Y. enterocolitica strain isolated from clinical material.

Twenty-eight clinical isolates of Yersinia enterocolitica were investigated for their abilities to produce heat-stable enterotoxin (YST). All 21 invasive strains (serogroup O3 biotype 4) carried the previously described gene for YST (yst), with toxin detectable in culture supernatants from 20 strains. One of seven noninvasive, biotype 1A strains also had enterotoxic activity, despite failure to hybridize with a probe for yst. The toxin produced by this noninvasive (serogroup O6) strain resembled YST in terms of molecular size, heat stability, and solubility in methanol. It differed from YST, however, with respect to regulation of its production by temperature and its mechanism of action, which did not appear to involve cyclic GMP.

Animals↗
PubMed1993

Mitral prosthetic dehiscence with laminar regurgitant flow signals assessed by transesophageal echocardiography.

A patient with a Björk-Shiley mitral prosthesis developed progressive heart failure without heart murmur and hemolysis. The prosthetic dehiscence was not diagnosed using transthoracic echocardiography, but transesophageal echocardiography. The regurgitant signals revealed laminar flow pattern with large regurgitant orifice. In patients with mitral prosthetic dehiscence with laminar flow pattern, transesophageal echocardiography can provide reliable diagnostic information.

Adult↗
PubMed1993

Haemodynamic changes associated with thermodilution cardiac output determination during metabolic acidosis or hypoxic hypoxia in dogs.

Haemodynamic alterations elicited by iced injectate during thermodilution cardiac output measurements were evaluated in the presence of metabolic acidosis or hypoxic hypoxia in 14 instrumented anaesthetized dogs. The alterations in some haemodynamic variables during slowing of the heart rate following injection of 3 ml iced injectate were slightly greater in metabolic acidosis and hypoxic hypoxia as compared to animals without metabolic acidosis or hypoxic hypoxia (P < 0.05), but the changes were clinically insignificant. No serious haemodynamic changes were found during any cardiac output measurement by thermodilution in the presence of metabolic acidosis or hypoxic hypoxia. The values of cardiac output measured by thermodilution correlated closely with those of pulmonary blood flow measured by an electromagnetic flowmeter in the metabolic acidosis and hypoxic hypoxia groups (r > 0.9). It is concluded that thermodilution using iced injectate will estimate right ventricular output accurately in conditions of metabolic acidosis and hypoxic hypoxia.

Acidosis↗