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Biomedical subjects

T Mizuguchi

Publications and source records attributed to T Mizuguchi.

At least 127 records · Page 7Linked to original sources
PubMed1988

Breathing pattern of anesthetized humans during pancuronium-induced partial paralysis.

We investigated the breathing patterns of 17 subjects anesthetized with enflurane before and after partial muscle paralysis produced by pancuronium bromide. In the face of significant muscle weakness produced by pancuronium, breathing patterns are characterized by decreases in both tidal volume and respiratory frequency. The decreased tidal volume corresponded to the decrease in occlusion pressure, indicating that the decreased tidal volume results solely from a decreased contractile force of the respiratory muscles. The decreased respiratory frequency was due to prolongation of both inspiratory and expiratory time without changing the ratio of the inspiratory time to the total breath time. Withdrawal of phasic vagal influence by airway occlusion before partial muscle paralysis revealed that an active Breuer-Hering inflation reflex was operative in only 8 of all 17 subjects. Since the contribution of the Breuer-Hering inflation reflex alone does not seem to account for the consistent decrease in respiratory frequency, some other mechanisms modulating respiratory frequency might be involved in the characteristic breathing patterns during partial muscle paralysis under enflurane anesthesia.

Adult↗
PubMed1988

Respiratory reflex responses to stimulation of tracheal mucosa in enflurane-anesthetized humans.

We investigated respiratory reflex responses to tracheal mucosa stimulation induced by injection of distilled water in 13 female patients under three different depths of enflurane anesthesia (0.7, 1.0, and 1.3 minimum alveolar concentration). Detailed analysis of the types of reflex responses revealed that there are at least six different responses: 1) the apneic reflex, 2) the expiration reflex, 3) spasmodic, panting breathing, 4) the cough reflex, 5) slowing of breathing, and 6) rapid, shallow breathing. Among these reflex responses, the cough reflex was the most sensitive and the apneic reflex followed by slowing of breathing was the most resistant to deepening anesthesia, whereas the sensitivity of other types of reflex responses was in between. Our results indicate that the types of respiratory reflex responses to tracheal mucosa stimulation are associated with depths of anesthesia and that the differences in sensitivity to anesthesia may be a valuable sign in clinical assessment of depth of anesthesia.

Adult↗
PubMed1988

Responses to severe hypoxia of phrenic and recurrent laryngeal nerve activity in vagotomized cats.

We investigated changes in activities of phrenic nerve (PN) and the recurrent laryngeal nerve (RLN) during progressive hypoxia produced by administration of a mixture of 5% O2 in N2 and a mixture of 5% O2 in N2O in 8 vagotomized, paralyzed, and artificially ventilated cats anesthetized with halothane. During progressive hypoxia produced by administration of 5% O2 in N2, both PN and RLN activities initially increased and then decreased at approximately the same rate. The relationship between PN and RLN activities during the respiratory stimulation and the relationship between PN and RLN activities during the depression due to hypoxia were both linear and were represented by the same linear regression line. The responses of PN and RLN activities to progressive hypoxia produced by administration of 5% O2 in N2O were basically similar to those observed during administration of 5% O2 in N2 although a concomitant increase in depth of anesthesia with N2O enhanced the occurrence of hypoxic respiratory depression. These results suggest that the respiratory modulation of recurrent laryngeal motoneuron activity is closely related to that of phrenic motoneuron activity and that both motoneurons share similar control mechanisms. Neither severe hypoxia nor addition of N2O to a halothane-anesthetized cat seems to affect the close linear relationship between PN and RLN activities.

Animals↗
PubMed1987

Serum osmolality gap in postoperative patients in intensive care.

The serum osmolality gap (OG), the difference between measured and predicted serum osmolality, was determined in 161 postoperative patients. A significantly increased OG was found in patients with failure of one or more organs, but rarely seen in those without organ failure. OG in non-survivors was significantly increased and sustained at a high level. Thus, the change in OG correlated with the severity of the patients' condition and their outcome. There was also a significant correlation between OG and hepatic cell function tests (arterial ketone body ratio and hepaplastin test). Analysis of non-aminoacid OG revealed that about 75% of the increased OG could be attributed to increased aminoacid concentrations, but that the remainder should be attributed to other undetermined solutes. Serial determination of OG provides information on metabolic abnormalities and prognosis of patients with progressively developing organ failure.

Amino Acids↗
PubMed1987

Effects of salbutamol and hyperventilation on the rise in serum potassium after succinylcholine administration.

It is known that circulating catecholamines stimulating beta 2-receptors and the acid-base balance play important roles in the regulation of serum potassium (K+). The present study was undertaken to investigate the effect of salbutamol (SB), a highly selective beta 2 agonist, and hyperventilation (HV)-induced alkalosis on the change in serum K+ after succinylcholine (SCh) administration in dogs. Pretreatment with SB (0.4 microgram.kg-1.min-1 for 30 min) produced sustained decreases in serum K+ and mean arterial pressure, and transient increases in cardiac output and serum insulin concentration. Maintaining respiratory alkalosis with HV (PaCO2 = 2.6-3.3 kPa) produced sustained decreases in serum K+ and cardiac output. Although both pretreatment with SB and HV-induced alkalosis significantly reduced the absolute increases in serum K+ after SCh, the effect of SB was more remarkable than that of HV. These results suggest that the degree of beta 2-receptor activity can strongly modulate the change in serum K+ after SCh administration.

Albuterol↗
PubMed1986

New equations to calculate temperature correction factors for PO2 in human blood.

Effects of hemoglobin concentration (Hb), pH, and body temperature (T) on the relationships between delta log PO2/delta T and PO2 were studied by means of a mathematical model using a Newton-Raphson iteration method. The functions between delta log PO2/delta T and PO2 were affected by the above three factors. New equations considering the effects of Hb, pH, and T were proposed by modifying the equation reported by Severinghaus: delta log PO2/delta T = (L +(U-L)/(A(vPO237)B + 1))(10(-2) where U = 3.15-0.45(7.4-pH37) L = 0.68-0.09(7.4-pH37) A = 5.86(exp10(0.074(T)-0.294(7.4-pH37)-11))((Hb)0.913) B = 6.33(exp10(-0.0051(T)))((Hb)-0.113) + 0.24(7.4-pH37) and vPO237 is virtual PO237 which may exist when PO237 is corrected to standard conditions (pH = 7.4, BE = 0) by the following equations: vPO237 = PO237(exp10(fB(7.4-pH37)-0.0013(BE))) fB = (PO237/26.6)0.08-1.52 where fB is the Bohr factor. The above equations provided values of delta log PO2/delta T which fit closely to those obtained by the complex iteration method with maximum differences of less than 1.3 X 10(-3) at T = 27, indicating that maximum % errors for PO2 at T (PO2T) are less than 3.0% at T = 27 and that our equations can be applied over a wide range of Hb, pH37 and T.

Bicarbonates↗