Tatsuhiko Kano

Epidural recording of spinal electrogram in man

Abstract A safe, simple method of recording human spinal electrogram (SEG) is described. The method is based on established techniques for administering epidural anesthesia and could be applied to the diagnosis of human spinal diseases and to physiological or pharmacological study of the human nervous system.

Fundamental patterns and characteristics of the laser-doppler skin blood flow waves recorded from the finger or toe

Three different components, Basic Wave (BW), Cardiac Wave (CW) and Reflex Wave (RW), among the laser-Doppler (L-D) skin blood flow waves on the finger- or toe-tip, were studied in 32 healthy volunteers. The cycle of the rhythmic BW was 8.1 +/- 1.7.min-1 and was independent of respiratory movements. The BW was synchronous with the baseline fluctuation in the digit-photoplethysmogram. Power spectral analysis of rhythmic fluctuations in the simultaneously recorded R-R interval on ECG, systolic blood pressure, and L-D skin blood flow disclosed that the BW was correspondent with the Mayer wave, i.e., low frequency component. The cycle of the CW was consistent with the heart rate and was superimposed on the BW. The RW was a transient marked reduction in blood flow, which was induced by a deep inspiration or various sensory stimuli. A sympathetic skin response on the palm and a venoconstrictive response on the occluded arm were observed concomitantly with the RW. Good synchronization was observed in each component of the L-D skin flow waves between the fingers and toes. These findings suggest that the BW and the RW on the finger- or toe-tip are predominantly driven by tonic and reflex phasic activities of descending sympathetic outflows via the supraspinal center, respectively.

Dermal patch anaesthesia: comparison of 10% lignocaine gel with absorption promoter and EMLA cream

The analgesic effects of transdermally applied 10% lignocaine aquagel containing 3% glycyrrhetinic acid monohemiphthalate disodium (as an absorption enhancer) and EMLA cream were compared on the forearms of 34 adult volunteers in a double‐blind fashion. The mean pinprick pain scores (graded by noting the number of painful pinpricks out of five) at 30, 60 and 90 min after application and 30 min after removal of the anaesthetics were 3.3 (0.3) (mean SE), 1.2 (0.3), 0.3 (0.1) and 0.3 (0.1) respectively, in the lignocaine gel group. Corresponding scores were 3.5 (0.3), 1.5 (0.3), 0.7 (0.2) and 0.1 (0.1) respectively, in the EMLA group. Insertion of a 26‐gauge needle into the treated skin to a depth of 1 mm at 90 min after application was not painful in 91% of the volunteers in the lignocaine gel group and 88% of those in the EMLA group. There was no significant difference in any of the corresponding pain scores between the two groups.

Evaluation of the central nervous function in resuscitated comatose patients by multilevel evoked potentials

Multilevel evoked potentials were examined in 17 patients who became comatose after cardiac arrest and resuscitation. In 4 patients, the P1 through N3 components of the somatosensory evoked cerebral potential (SECP) were present altogether within 100 ms after the ischemic insults. They all subsequently regained consciousness, though three of them developed intelligence and motor disturbances to some extent. In 11 patients who regained consciousness, or remained in a vegetative state, the evoked potentials which reflect brainstem functions, such as the auditory evoked brainstem potential, the R1 wave of the orbicularis oculi reflex and the slow positive wave of the somatosensory evoked brainstem potential, were recognized. The somatosensory evoked spinal potential and spinal monosynaptic reflex showed normal appearances in the state of vegetation and even after the determination of brain death. The measures of SECP could be useful in predicting restoration of consciousness.

Cardiopulmonary-cerebral resuscitation by using cardiopulmonary bypass through the femoral vein and artery in dogs.

Twenty-seven dogs, divided into three groups, were subjected to a normothermic ventricular fibrillation (VF) cardiac arrest of 15 min and resuscitated by using cardiopulmonary bypass through the femoral veins and artery (F-F bypass). Group I (n = 15): Cardiac beating did not return in any dogs during an initial 3-min conventional cardiopulmonary resuscitation, but it returned 5.2 +/- 3.8 min (mean +/- S.D.) after the successive initiation of the F-F bypass in all dogs, except in one with bypass trouble. Intermittent burst waves appeared on the electroencephalogram and continuous waves returned, 90.0 +/- 24.7 min and 130.7 +/- 28.1 min after the start of resuscitation, respectively. Values of blood glucose, lactate and potassium 5-15 min after the F-F bypass were significantly higher than those before induction of VF, while those of blood pH, base excess, hemoglobin, hematocrit, platelet and serum protein decreased significantly. Group II (n = 7): Both local cerebral (CBF) and myocardial blood flow (MCBF) returned to the pre-arrest level soon after the initiation of the F-F bypass, even though spontaneous cardiac beating was not yet restored. Closed or open chest cardiac massage could not produce as much blood flow as the F-F bypass did. In the early stage of restoration of spontaneous circulation, temporary interruption of the bypass led to a decrease in both local CBF and MCBF. Group III (n = 5): Spontaneous circulation was restored in all five dogs 5.2 +/- 1.1 min after the institution of the F-F bypass, which was continued for 164 +/- 30 min under mild hypothermia. After intensive care for a subsequent 6-36 h, the animals barked, moved their forelegs and could drink water. The mean neurological deficit score (normal: 0, brain death: 500) was 100.6. However, macroscopic examination of the brain in two dogs with prominent recovery revealed atrophy of the central gyrus and microscopic examination revealed injuries of the vulnerable neurons of the brain.

Effects of neural blockade and general anesthesia on the laser-Doppler skin blood flow waves recorded from the finger or toe

Effects of neural blockade and general anesthesia on the basic wave (BW) and the reflex wave (RW) among the laser-Doppler (L-D) skin blood flow waves recorded on the finger or toe were studied in 2 volunteers and 42 patients. The BW was continuous, rhythmic and independent of respiratory movements. The RW, which was induced by a deep inspiration or a snapping sound, was a transient marked reduction in blood flow. The BW was almost flattened and the RW was no longer induced at the finger under complete wrist block (n = 2), or under cervical or upper thoracic epidural anesthesia extended caudally over T7 (n = 2). On the other hand, the BW was still detected with reducing frequency and the RW could be provoked with one exception at the finger on the side with a sympathetic ganglion block at the C6 vertebral level (n = 14). The BW and RW at the toe were retained under lumbar subdural anesthesia (n = 6) as well. However, under the combination of lumbar subdural anesthesia and lower thoracic epidural anesthesia extending rostrally over T4 (n = 6), both the BW and the RW disappeared at the toe. In the course of deepening nitrous oxide/enflurane anesthesia (n = 10), the BW gradually reduced in frequency until it was almost flattened, and it became difficult to provoke the RW. L-D flowmetry of the finger or toe could be a useful clinical measure for detecting the presence or absence of sympathetic function controlling cutaneous vasomotion.

Quantitative assessment of the autonomic nervous system activities during atropine-induced bradycardia by heart rate spectral analysis

Using power spectral analysis of heart rate fluctuation, autonomic nervous system activities in bradycardia appearing in the initial phase of atropine administration were evaluated quantitatively in 16 healthy females. Atropine sulfate (10 micrograms/kg), diluted in 100 ml of 0.9% NaCl solution, was intravenously infused at a rate of 0.5 micrograms/kg per min. Electrocardiograms were sampled for 4 min for later analysis before and 0, 5, 10, 15 and 20 min after initiation of atropine infusion. Powers of low (LFC, 0.05-0.15 Hz) and high-frequency (HFC, 0.15-0.4 Hz) components in the power spectrum of R-R interval variations, and the LFC/HFC ratio were determined at each sampling point. HFC power at 0-4 min increased from 1.11 +/- 0.18 ms2 (mean) of baseline value to 1.37 +/- 0.19 ms2 (P < 0.05). The next 5-9-min value of 1.48 +/- 0.14 ms2 was the maximum, and the amount of atropine infused by 9 min was 4.5 micrograms/kg. The HFC powers following this point decreased. The 20-24-min value after 10 micrograms/kg atropine decreased to 0.21 +/- 0.03 ms2 (P < 0.01), which was lower than the previous 15-19-min value of 0.36 +/- 0.04 ms2 (P < 0.01). The LFC/HFC ratios showed no significant change for the initial 9 min of the atropine infusion. However, these ratios at 15-19 min and 20-24 min were increased from 0.50 +/- 0.04 (mean) of baseline value to 0.75 +/- 0.09 and 0.81 +/- 0.09, respectively (P < 0.01). A transient vagotonic state after atropine administration, followed by the well-known vagolytic state, was quantitatively detected by non-invasive spectral analysis of heart-rate fluctuation.

A case of colonic gas explosion caused by electrocautery.

A 70-year-old female with disturbed consciousness was admitted on the suspicion of liver cirrhosis, and potal embolism was detected. Since hepatic encephalopathy repeatedly occured thereafter, bypassing of the splanchnic vein and the umbilical vein was planned. Anesthesia was induced by thiamylal 250 mg IV and endotracheal intubation was performed using soccinylcoline 60 mg IV. Anesthesia was maintained with nitrous oxide (50%)oxygen-enflurane (0.5~1.5%) at a total flow of 4 [·minI • Pancuronium was used for muscle relaxation when necessary. The planned bypass operation proceeded without problems for about 9 hr until closure of the abdomen. However, the entire intestine was

Dermal patch anaesthesia for venous cannulation with 10% lignocaine gel containing glycyrrhetinic acid monohemiphthalate disodium as an absorption promoter

The clinical efficacy of transdermal 10% lignocaine gel mixture containing 3% w/w glycyrrhetinic acid monohemiphthalate disodium as an absorption promoter was evaluated at venous cannulation in 17 paediatric (6–11 years) and 17 adult (29–65 years) patients. After about 60 min of occlusive application, the mean (SD) pinprick pain score was 0.7 (0.7) in the paediatric group, compared with 1.4 (1.3) in the adults (p < 0.05). Twenty‐five patients (14 children and 11 adults) who had a pinprick score of 0 or 1 underwent venous cannulation without intradermal local anaesthetic. The mean (SD) pain scores at venepuncture showed no significant differences between children and adults.

Periodic abnormal fluctuations of blood pressure, heart rate and skin blood flow appearing in a resuscitated comatose patient

Fluctuations with a period of several tens of seconds, so called third-order waves, were recognized in the blood pressure, heart rate and Laser Doppler skin blood flow of a comatose patient following cardiac arrest and resuscitation. The waves fluctuated with an abnormally high amplitude and were apparently synchronous with each other. These abnormal fluctuations appeared continuously over 6 h on the day of resuscitation, while their periodicity gradually lengthened. The patient remained in a comatose state for the next 4 days. During that period, functional signs of the sympathetic nervous system, such as peripheral vasomotion and perspiration, were also absent. However, on the 6th post-resuscitation day, when the patient exhibited signs of restoring consciousness, he also regained some sympathetic function. This patient subsequently recovered full consciousness, although abnormalities of intelligence and motor function remained to some extent.