Precordial compression without airway management induces lung injury in the rodent cardiac arrest model with central apnea.

To investigate whether the lung injury induced by precordial compression without ventilation or not, in the cardiac-arrest animal model with central apnea. Thirty male Sprague-Dawley rats were anesthetized with halothane. The cardiac arrest was induced by 100 mg/kg ketamine (IV) and accompanied with central apnea. They were allocated to four groups by means of resuscitation. Group A was treated with only precordial compression without the other treatments. In group B with tracheotomy and precordial compression. In group C was performed tracheotomy, oxygenation, and precordial compression. The animals in group D were treated with tracheotomy, oxygen administration, artificial ventilation, and precordial compression. Four minutes after cardiac arrest, the resuscitation was started and continued for 20 min. PaCO(2) in the group without mechanical ventilation increased significantly after the start of the resuscitation. All animals were sacrificed after resuscitation procedure. The wet/dry weight ratio of lung in group A (6.9+/-0.8) was significantly higher than that of the other groups B, C and D (5.9+/-0.6, 5.7+/-0.4 and 5.6+/-0.4, P<0.05 in each). The pathological findings also demonstrated the lung injuries, such as edema, migration, and destruction of structure in group A. The precordial compression alone did not improve CO(2) elimination in the gasping-less cardiac arrest model, as well as maybe inducing more severe lung injury than that with the protective management. This experimental model raises the possibility that chest compressions without airway management might result in lung injury.

Global brain ischemia produced by clamping left subclavian artery and bicarotid trunk in the rabbit.

Thirty-five rabbits were divided randomly into 5 groups: sham operation, 10 minutes clamping bicarotid trunk (partial ischemia, PI), and 3 groups of 5, 7, and 10 minutes clamping left subclavian artery and bicarotid trunk (global ischemia, GI). Systolic arterial pressure increased slightly in the PI group, but doubled in the GI groups during clamping. Heart rate did not change in the PI group, but decreased transiently in the GI groups during clamping. Brain temperature decreased gradually in the GI groups during clamping, but did not change in the PI group. Necrotic changes were present 96 hours later in approximately 50% of the hippocampal CA1 cells in the GI groups, but in none of the cells in the PI and sham operation groups. The present results may indicate that clamping left subclavian artery and bicarotid trunk in the rabbit brings about global brain ischemia.

[The study of the anesthetic action of halothane on the rat spinal cord by fos immunoreactivity].

This study was performed to examine the anesthetic action of halothane on the spinal cord of rats by using fos immunoreactivity, a marker for neuronal activity following noxious stimulation. Sprague-Dawley rats were injected with 150 microliters of 5% formalin subcutaneously into the left hindpaw. Control group (n = 5) received 100% oxygen for 3 hours after injection. 1 MAC group (n = 5) and 1.5 MAC group (n = 5) of rats were anesthetized with 1 MAC or 1.5 MAC halothane, respectively, for 3 hours after injection. The number of fos immunoreactive cells was counted in the lumbar spinal cord of each rat. All rats showed escape reactions against noxious stimulation in the control group. In the 1 MAC and 1.5 MAC groups, two of five rats showed response to noxious stimulation and the another three showed no response, respectively. There was profound relation between the responding rats and the expression of fos immunoreactivity in the spinal dorsal horn. The number of fos immunoreactive cells decreased in the cord of rats that showed no response to noxious stimulation by halothane 1 or 1.5 MAC. These findings suggest that halothane has analgesic action on spinal nociceptive neurons in the rats on the condition that its reactions to noxious stimulation are suppressed by halothane of any concentration.

Utility of colorimetric end-tidal carbon dioxide detector for monitoring during prehospital cardiopulmonary resuscitation.

The purpose of this study was to evaluate a colorimetric end-tidal CO2 (ETCO2) detector (EASY CAP) as a monitor during prehospital cardiopulmonary resuscitation (CPR) without tracheal intubation. This detector was used for 121 patients during CPR with a laryngeal mask airway or face mask by authorized emergency lifesaving technicians. At 7 to 15 minutes after the initiation of CPR, ETCO was <0.5% in 30 cases (group A), 0.5% to 2.0% in 46 cases (group B) and >2.0% in 45 cases (group C). The rate of return of spontaneous circulation was 17% in group A, 24% in group B, and 48% in group C (groups A v C, P < .01). There was a significant difference in the rate of hospital admission between groups A and C. The ETCO2 value may be useful for monitoring during prehospital CPR with a laryngeal mask airway or face mask.

Ca(2+)-activated K+ current induced by external ATP in PC12 cells.

1. The effect of external ATP on the membrane current was investigated in PC12 cells by whole-cell voltage-clamp techniques. 2. Lower concentrations of ATP (1 or 10 mumol/L) induced only an inward current at 1 mmol/L EGTA in the K+ pipette solution, while higher concentrations of ATP (100 mumol/L and 1 mmol/L) induced an outward current following the inward current. 3. Lowering the EGTA concentration in the pipette solution induced a larger outward current following ATP application. The membrane potential at which the outward current crossed with the control before ATP application was more negative at lower concentrations of EGTA in the pipette. 4. The development of the outward current was blocked by a Ca(2+)-free external solution, 5 mmol/L tetraethylammonium and a Cs+ pipette solution instead of K+, indicating that the outward current was a Ca(2+)-activated K+ current. 5. Charybdotoxin (0.1 mumol/L) and iberiotoxin (0.1 mumol/L), but not apamin (0.2 mumol/L) blocked the development of the outward current, indicating the ATP-induced outward current is a BK-type Ca(2+)-activated K+ channel current and not the SK type. 6. UTP had no effect on the membrane current, indicating that the ATP-induced current change was not mediated by P2u but by P2x purinoceptor. 7. In conclusion, stimulation of P2x purinoceptors by ATP induces a Ca(2+)-permeable inward current that results in increases in intracellular Ca2+ concentrations and activation of a BK-type Ca(2+)-activated K+ current in PC12 cells.

[The effect of cervical sympathectomy on the pituitary and pineal endocrine system].

It was reported previously that continuous exposure to light in male rats increased serum luteinizing hormone (LH) and bilateral cervical sympathectomy inhibited such a change. In the present report, to examine the effect of cervical sympathectomy on the pineal endocrine function, 30 male rats were assigned to five groups. The control (C) group and the light (L) group underwent sham sympathectomy as well as sham pinealectomy. The sympathectomy (S) group underwent sympathectomy and sham pinealectomy. The pinealectomy (P) group and pinealectomy-melatonine (PM) group underwent sympathectomy and pinealectomy. The C group was kept under a normal circadian rhythm for 10 days, and the other groups were kept under continuous exposure to light for the same period. The PM group received subcutaneously 10 mg.kg-1 of melatonine every day. Serum LH levels were measured 10 days following these experiments. With regard to serum LH levels, the differences among C group, L group, and S group were similar to those previously reported. It was higher in P group (2.53 +/- 0.40 ng.ml-1) than in S group (1.58 +/- 0.61 ng.ml-1), and lower in PM group (2.08 +/- 0.31 ng.ml-1) than in P group. In conclusion, it is suggested that the endocrine activity of melatonine from the pineal gland plays an important role in the appearance of the effect of cervical sympathectomy.

[Effect of positive end-expiratory pressure on respiration and hemodynamics in dogs with pulmonary edema caused by increased membrane permeability].

The effect of PEEP on the extravascular lung water, respiratory mechanics and hemodynamics were studied in dogs with oleic acid-induced pulmonary edema. The dogs were randomized into one of three groups according to PEEP of 0, 5 and 10 cmH2O, 60 minutes after oleic acid (0.1 ml.kg-1) injection. PEEP improved oxygenation accompanied by increased FRC and DLco. However, oxygen delivery decreased in association with the decreased cardiac index caused by application of PEEP. PEEP failed to decrease the extravascular lung water volume measured by double-indicator dilution technique after lung edema formation.

[A case of ABO blood group incompatibility treated by exchange transfusion].

A patient with ABO blood group incompatibility who was treated by exchange transfusion is reported. A 63-year-old woman with blood group B type Rh (+) was accidentally transfused approximately 120 ml of A type Rh (+) packed red cells. She developed shock state, complaining chilliness, trepidation, nausea and vomiting just after the atypical blood transfusion. Fortunately, we could save her life without any complication by doing exchange transfusion in addition to anti-shock therapy and anticoagulant therapy preventing disseminated intravascular coagulation. The exchange transfusion was performed while monitoring central venous pressure. The total withdrawn blood reached 4300 ml, and 18 units of B type Rh (+) packed red cells, 10 units of AB type Rh (+) fresh frozen plasmas, 1250 ml of plasma protein fractions and 1750 ml of plasma expanders were infused with crystalloid fluid therapy. Although the amount of atypical blood transfusion to her was relatively small, it is considered that the exchange blood transfusion which seems to be only the fundamental therapy against atypical blood transfusion, took effect in saving her life without any complication.

[Placental transfer of vecuronium administered with priming principle regimen in patients undergoing cesarean section].

Eight women having cesarean section under general anesthesia received vecuronium (VCB) 0.01 mg.kg-1 as a priming dose, followed 180 s later by 0.11 mg.kg-1 as an intubation dose. Subsequently, VCB concentrations of umbilical venous and maternal arterial blood at delivery were assayed. The time from the injection of intubation dose to delivery was 283 +/- 55 (mean +/- SD) s. Umbilical and maternal VCB concentrations at delivery were 79.4 +/-36.1 1ng.ml-1 (UV) and 1258.3 +/- 464.1 ng.ml-1 (MA). respectively. Thus, the umbilical venous to maternal arterial VCB concentration ratio (UV.MA-1) was 0.07 +/- 0.02. One-min and 5-min Apgar scores were 8-9 and 9-10, respectively. Judging from previous reports concerning VCB administration during cesarean section, total of VCB 0.12 mg.kg-1 may be an overdose. We concluded therefore that of total VCB 0.10 mg.kg-1 seems to be an appropriate dose for cesarean section.

[The effect of nicardipine hydrochloride upon the pulmonary arterial pressure].

This study examines the effects of induced hypotension with intravenous administration of nicardipine hydrochloride (NIC) upon pulmonary arterial pressure (PAP) undergoing modified radical mastectomy with neuroleptanesthesia (NLA-group; 3 cases) and inhalation anesthesia (N2O+ isoflurane; GOI-group; 3 cases). Systolic arterial pressure was reduced and maintained at 80 mmHg. During and after induced hypotension in NLA-group, heart rate (HR), cardiac index, pulmonary arterial pressure (PAP) increased remarkably. On the other hand, systemic vascular resistance index was reduced. In GOI group, no significant changes were seen in PAP. The acceleration of the autonomic baro-reflex induced by decreased blood pressure produced by NIC may be depressed under anesthesia to initiate this difference in response of HR to NIC. The data indicate that this depressive effect of NLA on this reflex is weak, and NIC is a potent systemic vasodilator with hyperdynamic hemodynamic effects in addition to an increase in right ventricular function, and PAP was increased.

Cervical sympathectomy affects adrenocorticotropic hormone and thyroid-stimulating hormone in rats.

To examine the effects of bilateral cervical sympathectomy on the secretion of adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), and prolactin (PRL), 18 male rats were divided into three groups: control (Cont), sham operation (Sham), and bilateral cervical sympathectomy (Symp). All rats were kept under a normal circadian rhythm for 2 weeks. Subsequently, blood was collected and plasma ACTH as well as serum TSH, GH, and PRL levels were measured. The difference in ACTH levels between the Cont and Sham groups was not significant, but ACTH levels in the Symp group were significantly higher than those in the other groups. The difference in TSH levels between the Cont and Sham groups was also not significant, but TSH levels in the Symp group were significantly lower than those in the Cont group. There were no statistically significant differences in GH and PRL levels among these groups. The present results suggest that cervical sympathectomy in the rat increases ACTH secretion and decreases TSH secretion in the pituitary. These effects seem to be due to a mildly increased secretion of melatonin in the pineal body that probably in turn increases corticotropin-releasing factor (CRF) secretion and decreases thyrotropin-releasing hormone (TRH) secretion in the hypothalamus. Extrapolation of these findings to humans suggests that longterm and repeated stellate ganglion block would affect the pituitary secretions of ACTH and TSH.

Cervical sympathectomy inhibits axonal transport of gonadotropin-releasing hormone during continuous exposure to light in male rats.

To examine the effects of cervical sympathectomy on the transport of gonadotropin-releasing hormone (GnRH) between the hypothalamic neurons and the median eminence, 16 male rats were assigned into four groups: control (C), light (L), light-sympathectomy (LS), and light-colchicine (LC). The C group was kept under a normal circadian rhythm for 2 weeks, and the L group was kept under continuous exposure to light for the same period. The LS group underwent bilateral cervical sympathectomy before being kept under continuous light conditions for 2 weeks. The LC group received colchicine into the cerebral ventricle after being kept under continuous light for 12 days; subsequently, this group was also housed for 2 days under continous light. After these procedures, blood was collected and serum luteinizing hormone (LH) levels were measured. All rats were perfused with a fixative, and GnRH neurons around the anterior commissure, as well as GnRH fibers and granules in the median eminence, were stained immunohistochemically. The L group showed a decreased number of GnRH neurons, increased concentrations of GnRH fibers and granules, and an increased LH level; however, in the LS and LC groups, these changes were not seen. The response in the LS group resembled that in the LC group. Considering the action of colchicine, which inhibits axonal transport, it is suggested that cervical sympathectomy also inhibits axonal transports of GnRH between the GnRH neurons and the median eminence during continuous exposure to light.

In vivo pharmacological study of spermine-induced neurotoxicity.

Spermine-induced neurotoxicity and its pharmacological manipulation was studied in the rat striatum in vivo. Spermine (50, 100, 250 nmol) was injected into the striatum and the volume of damage quantified by computer-based image analysis. Spermine produced a dose-dependent increase in the volume of damage. Co-administration of MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate; dizocilpine, 60 nmol), 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline (25, 40 nmol) and pretreatment with pentobarbital (40 mg/kg, i.p.) significantly reduced the volume of damage induced by 100 nmol spermine. MK-801 (30 nmol) was also effective in reducing the damage induced by 50 nmol spermine. Treatment with a specific inhibitor of nitric oxide synthase, N omega-nitro-L-arginine methyl ester (50 mg/kg, i.p., twice daily for 10 days) was ineffective. These results suggest an involvement of both N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors in the cascade of spermine-induced neurotoxicity.

[Changes in analgesic levels, plasma concentrations and epidurogram during long-term continuous epidural block].

The change of analgesic levels, plasma concentrations and the radiographical changes of epidural space due to continuous epidural block were studied in 54 patients receiving pain relief. All the patients received 2 ml per hour of 2% lidocaine or 0.5% bupivacaine via the catheter over two weeks. The effect of epidural block was determined on 1, 2, 4, 7, 10 and 14 days, the epidurogram was performed on 1, 7, 14 days, and plasma concentration of lidocaine or bupivacaine was measured on 1, 3, 7, 14 days. We removed catheters in 8 patients because of infection around the catheter, pain in the back during injection, the leakage of anesthetics, and spontaneous removal. The effects and plasma concentrations of epidural block decreased significantly after a week, and the mean segmental number of radiographic spread decreased significantly after two weeks. The decreasing effect or duration of epidural block was due to decrease in spread of anesthetics because of adhesion around the catheter in the epidural space. We conclude that the safety period of continuous epidural block is within 2 weeks.

[The effect of flumazenil in reversing midazolam, flunitrazepam or diazepam].

In 31 adult patients who had undergone spinal or epidural anesthesia, we evaluated the effect of flumazenil in reversing midazolam, flunitrazepam or diazepam. The patients received midazolam 5 mg, flunitrazepam 1 mg or diazepam 5 mg 15 min after the spinal or epidural anesthesia. After the completion of operation, flumazenil (0.2 mg-1.0 mg) was administered until the patient became awake. Blood pressure, pulse rate and respiratory rate before and after administration of flumazenil showed no statistically significant changes in these groups. There were no significant differences in necessary amount of flumazenil among these groups. The time necessary for the patient to be awake in midazolam group was significantly shorter than that in flunitrazepam or diazepam group. Half of the patients in flunitrazepam and diazepam groups slept again after leaving the operating room, but they presented no clinical problems. In conclusion, we consider that flumazenil does not affect circulation and respiration, so it seems to be safe and effective for reversing benzodiazepins in clinical situation.

[Use of ketamine combined with local anesthetics in epidural anesthesia].

Postoperative pain relief and sedation with epidural ketamine were studied. Twenty-four patients for elective upper abdominal surgery were divided into 4 groups. Epidural catheter was inserted into thoracic epidural space before induction of general anesthesia. In each group, either 0.25% bupivacaine 5 ml only, ketamine 0.1 mg.kg-1 + bupivacaine 5 ml, or ketamine 0.3 mg.kg-1 + bupivacaine 5 ml, or ketamine 0.5 mg.kg-1 + bupivacaine 5 ml was injected into epidural catheter for complaint of pain in recovery room. In ketamine injected groups, blood pressure and heart were unchanged, but respiration rate increased significantly. Patients in ketamine 0.3 or 0.5 mg.kg-1 injected groups, pain relief and sedation score were significantly intensified, but patients in ketamine 0.5 mg.kg-1 injected group, incidence of pain in the back during injection and headache was high. We conclude that epidural ketamine is useful for postoperative pain relief, and the superior dose of epidural ketamine is 0.3 mg.kg-1.

[A case of pulmonary infiltrates associated with a neutrophil-specific antibody transfusion reactions].

A normovolemic pulmonary edema associated with blood transfusion developed in a 38-year-old woman during gynecological operation. Bilateral pulmonary infiltrates and profound leucopenia (700.microliters-1) were observed. An antibody reactive with the recipient's neutrophils was found in a donor and an antibody reacting with the lymphocytes of the recipient was identified in another donor. Both donors were multiparous women. Respiratory failure was improved with mechanical ventilation but chest X-ray showed pulmonary infiltrates for the next 3 days. The white blood cell count rose to 2900.microliters-1 in the next day, and it took 2 weeks to be normalized. Transient pulmonary infiltrates can be caused by antileukocyte antibodies passively transfused by multiparous donors.