[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.

Mechanisms of vasodilation of cerebral vessels induced by the potassium channel opener nicorandil in canine in vivo experiments

BACKGROUND AND PURPOSE

Nicorandil, a potent antianginal agent characterized as a potassium channel opener, could produce cerebrovascular dilation in in vitro studies. Our aim was to investigate the pharmacologic response to the topical application of nicorandil on the vasomotor tone of pial vessels in vivo. To elucidate its mechanism, we also studied the inhibitory action of methylene blue and glibenclamide against nicorandil-induced vasodilation.

METHODS

In 14 dogs prepared with a parietal cranial window, we administered five different concentrations of nicorandil solution (10(-7), 10(-6), 10(-5), 10(-4), and 10(-3) mol/L) under the window and measured pial arterial and venular diameters. After pretreating pial vessels with either 10(-5) mol/L methylene blue or 10(-5) mol/L glibenclamide, we examined inhibitory action after the application of 10(-5) mol/L nicorandil. In additional experiments with 9 dogs, we evaluated the effects of nitroglycerin and cromakalim on pial vessels in the absence or presence of 10(-5) mol/L methylene blue and 10(-5) mol/L glibenclamide, respectively.

RESULTS

Nicorandil produced significant, concentration-dependent dilation of pial vessels (P < .05). Methylene blue blocked nicorandil-induced dilation, whereas glibenclamide only attenuated such action of nicorandil. Nitroglycerin and cromakalim also produced a concentration-dependent increase in pial arteriolar and venular diameters (P < .05), and those effects were blocked in the presence of methylene blue or glibenclamide, respectively.

CONCLUSIONS

Our in vivo study demonstrates that topical application of nicorandil dilates both pial arterioles and venules in a concentration-dependent manner and suggests that the mechanisms of such actions are most likely due to both cyclic GMP-mediated vascular smooth muscle dilation and the regulation of K+ flux.

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).

[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.

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.

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.

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.

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.

Nonrespiratory rhythmic fluctuations in systemic arterial pressure in anesthetized humans

STUDY OBJECTIVE

To clarify the frequency of nonrespiratory rhythmic fluctuations in systemic arterial pressure (vasomotor waves) and to identify the clinical conditions in which the vasomotor waves develop in humans under anesthesia.

DESIGN

Retrospective analysis of collected data.

SETTING

Inpatient surgery clinic at a university hospital.

PATIENTS

Five hundred thirteen consecutive ASA physical status II-V patients.

INTERVENTIONS

Direct arterial pressure monitoring and general anesthesia, including high-dose fentanyl, enflurane, enflurane plus fentanyl, cervical or thoracic epidural, and lumbar epidural anesthesia.

MEASUREMENTS AND MAIN RESULTS

Among the anesthesia techniques used, vasomotor waves occurred most frequently in patients anesthetized with high-dose fentanyl (31.1%) and least frequently in those with high-level epidural blockade (7.4%). As a result of multiple logistic analysis, the contributing factors to the appearance of vasomotor waves were the institution of cardiopulmonary bypass (CPB) and the patient's age. It is also a novel finding that nearly one-third of the vasomotor waves developed in patients under stable hemodynamic conditions.

CONCLUSIONS

Vasomotor waves are a common phenomenon in relatively high-risk patients during general anesthesia. The appearance of vasomotor waves is significantly related to CPB and patient age.

[Perioperative pulmonary thromboembolism. A clinical study]

Pulmonary embolism (PE) is a major catastrophe during postoperative period. We had six patients who developed PE after surgery and one during anesthesia and surgery. Severe arterial hypoxemia (PaO2 41 +/- 14 mmHg) occurred in all six postoperative patients, but not in a patient who developed PE under anesthesia. In 3 patients with pulmonary artery catheter in place, pulmonary arterial pressure (PAP) increased significantly during the embolic events. PAP tended to decrease before the apparent improvement of PaO2 in each patient. This suggests that increases in anastomotic bronchial blood flow occurred following the events. In a patient who developed PE under enflurane-N2O-O2 anesthesia, neither hypoxemia nor hypotension occurred despite significant increase in PAP. All patients received heparin and urokinase intravenously, which caused persistent bleeding in two patients. It remains for further investigations to study the mechanisms of serious hypoxemia in postoperative patients with PE as well as those of favorably maintained pulmonary oxygenation in a patient with PE under general anesthesia.

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.

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.

[Investigation of meropenem levels in the human bone marrow blood, bone, joint fluid and joint tissues]

A solution of 0.5 g of meropenem (MEPM) in 100 ml of saline was administered to adult patients before the orthopaedic surgery via intravenous drip infusion for 30 minutes. Eleven samples of bone marrow blood, 13 bone, 8 joint fluid and 8 joint tissues obtained from 15 clinical cases were analyzed for MEPM levels. At the same time, blood samples were taken from peripheral veins and serum served as control was analyzed. The concentration of MEPM in the marrow blood at 30 minutes after administration of MEPM reached 15.4 micrograms/ml, which was above 50% of the maximum concentration in serum. Ratios of concentration in bone marrow to that in serum were between 93% and 105% at that time. MEPM levels were 5.74-0.40 micrograms/g in bones, 20.3-4.55 micrograms/ml in joint fluid and 18.2-4.05 micrograms/g in joint tissues at 30 to 75 minutes after administration. In joint fluid and joint tissues, the concentration above 50% of maximum level in serum were maintained for more than an hour. MEPM is thought to be useful for the treatment of bone and joint infections and also prophylaxis of infections in cases of major surgery of skeletal tissue in the field of orthopaedic surgery.

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.

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.

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.

Age-related increase in systolic fraction of pulmonary vein flow velocity-time integral from transesophageal Doppler echocardiography in subjects without cardiac disease

The pulmonary vein flow velocity-time profile would be equivalent to the pulmonary vein flow volume-time profile, provided that the cross-sectional area of the pulmonary vein remains unchanged during 1 cardiac cycle. The systolic fraction of the pulmonary vein flow velocity-time integral, a ratio of velocity-time integral of the S wave to the sum of velocity-time integrals of the S and D waves, represents the ratio of left atrial storage volume to left ventricular stroke volume. This systolic fraction may help early filling of the left ventricle through an appropriate storage of blood and generation of driving pressure in the left atrium. Because early filling of the left ventricle is progressively impaired with age, it was hypothesized that this systolic fraction is increased with age. Forty-four noncardiac surgical patients (age range 17 to 70 years) who underwent transesophageal Doppler echocardiography under general anesthesia were studied, and left upper pulmonary vein flow and mitral inflow velocities were recorded. The ratio of peak velocity of the E wave to that of the A wave of mitral inflow velocity-time profile (y) decreased with age (y = -0.0245 x age + 2.41; r = -0.672, p < 0.01). Systolic fraction (y) increased with age (y = 0.00373 x age + 0.514; r = 0.656, p < 0.01). The age-related increase in the systolic fraction of pulmonary vein flow velocity-time integral may account for the compensation for impaired early filling of the left ventricle in elderly patients.

Haemodynamic changes associated with thermodilution cardiac output determination during myocardial ischaemia or pulmonary oedema in dogs

Since the technique of thermodilution (TD) cardiac output measurements per se causes haemodynamic alterations, the authors examined whether the alterations elicited by iced injectate are augmented in the presence of myocardial ischaemia (MI) or pulmonary oedema (PE), compromised conditions frequently associated with critically ill patients. MI (N = 7) or PE (N = 7) was induced by clamping the anterior descending coronary artery or by a slow infusion of oleic acid into the right atrium, respectively, in anaesthetized dogs. Injection of iced injectate, 3 ml, caused similar changes in heart rate, mean systemic and pulmonary arterial pressures, pulmonary blood flow, right ventricular dP/dt, and right atrial pressure in dogs with and without MI or PE. Cardiac output estimated by TD correlated closely with pulmonary blood flow measured by electromagnetic flowmeter in both MI and PE (r > 0.9). No profound alterations in haemodynamics were observed at any injection during TD cardiac output measurements under MI or PE. These results indicate that TD cardiac output determination does not cause serious haemodynamic alterations, and can estimate right ventricular output accurately under MI and PE.

[Anaphylactoid reactions to contrast media which occurred during cholecystectomy and subsequent disseminated intravascular coagulation--a case report]

A 67-year-old woman without any history of allergic episode developed severe hypotension (40 mmHg) without skin rash one minute after the administration of amidotrizoic acid for intraoperative cholangiography during thoracic epidural and light general anesthesia. Although ephedrine, methoxamine, dopamine and norepinephrine were administered, severe hypotension persisted for three hours and epinephrine was only effective. Marked elevations of serum levels of histamine, leukotriene D4 and leukotriene E4 were noted after the episode, suggesting the occurrence of the anaphylactoid reaction to amidotrizoic acid and the activation of the immunological complement system. After the recovery from the anaphylactoid reaction, the patient developed disseminated intravascular coagulation (DIC) and severe bleeding around the wound for which reoperation was needed. It is necessary to consider some prophylactic treatments against DIC when severe anaphylactoid reaction occurred.

Distribution patterns and frequency of proliferating cells in cutaneous keratinocytic neoplasms. Immunohistochemical study with a monoclonal antibody (TOB7) used against proliferating cell nuclear antigen

BACKGROUND

Almost all markers for proliferating cells need freshly frozen tissues for evaluation; therefore retrospective study is impossible.

OBJECTIVE

In the present study, a murine monoclonal antibody (TOB7) against the proliferating cell nuclear antigen (PCNA) was used for the analysis of cell kinetics of cutaneous keratinocytic neoplasms. The antibody is applicable to formalin-fixed, paraffin-embedded tissues.

METHODS

The frequency of PCNA-positive cells and their distribution patterns were immunohistochemically investigated in various cutaneous keratinocytic neoplasms.

RESULTS

Squamous cell carcinoma and Bowen's disease showed significantly increased numbers of PCNA-positive cells when compared with other keratinocytic neoplasms. A characteristic marginal or random distribution pattern of PCNA-positive cells was observed in the lesions of each disease category.

CONCLUSION

Important information on the growth dynamics of keratinocytic neoplasms was obtained in this retrospective immunohistochemical study.

[Anaphylactic shock with ventricular fibrillation induced by chlorhexidine]

We experienced a case in which a 66 year-old male patient developed anaphylactic shock followed by ventricular fibrillation, possibly due to intravenous aspiration of chlorhexidine used for topical application when right internal jugular vein was punctured. He was successfully resuscitated without any sequelae. Although lymphocyte transformation test failed to identify the specific allergen, IgE antibodies against chlorhexidine in the patient's serum were detected by radioallergosorbent technique. Chlorhexidine is an extensively used antiseptic, but there have been many reports regarding severe adverse reactions associated with its use. Chlorhexidine does not seem to be a safe antiseptic.

[The relation between upper respiratory tract infection and mild hypoxemia during general anesthesia in children]

Anesthesiologists often face the problem of a child with symptoms of an acute upper respiratory infection (URI) presenting for surgery. Anesthesia in the presence of uncomplicated URI may not be contraindicated. However, we experienced three cases of such children in which lung atelectasis developed after the induction of general anesthesia. Because continuous monitoring of arterial oxygen saturation by pulse oximetry (SpO2) was useful for detecting mild hypoxemia in these patients, we retrospectively examined the possible association between URI symptoms and SpO2 in 63 children. Patients with symptoms of URI showed a significantly high incidence of decreased SpO2 to below 95% for 5 minutes. Our results suggest that, with URI symptoms even uncomplicated, symptomatic patients have increased risks for the development of mild hypoxemia during anesthesia.