Satoru Oku

Comparison of Percutaneous Electrical Nerve Stimulation with Transcutaneous Electrical Nerve Stimulation for Long- Term Pain Relief in Patients with Chronic Low Back Pain

The long-term effect of percutaneous electrical nerve stimulation (PENS) on chronic low back pain (LBP) is unclear. We evaluated the number of sessions for which PENS should be performed to alleviate chronic LBP and how long analgesia is sustained. Patients underwent treatment on a twice-weekly schedule for 8 wk. Group A (n = 18) received PENS for 8 wk, group B (n = 17) received PENS for the first 4 wk and transcutaneous electrical nerve stimulation (TENS) for the second 4 wk, and group C (n = 18) received TENS for 8 wk. Pain level, degree of physical impairment, and the daily intake of nonsteroidal antiinflammatory drugs (NSAIDs) were assessed before the first treatment, 3 days after Week 2, Week 4, and Week 8 treatments, and at 1 and 2 mo after the sessions. During PENS therapy, the pain level decreased significantly from Week 2 in Groups A and B (P < 0.05 or 0.01), and physical impairment and required NSAIDs decreased significantly from Week 4 (P < 0.05 or 0.01) in Group A but only at Week 4 in Group B (P < 0.05 or 0.01). These effects were sustained until 1-mo follow-up (P < 0.01) in Group A but not in Group B; these effects were not observed at 2-mo follow-up even in Group A. In Group C, pain level decreased significantly only at Week 8 (P < 0.05). Our results indicate that repeated PENS is more effective than TENS for chronic LBP but must be continued to sustain the analgesic effect.

Renal Sympathetic Nerve Activity After Dexmedetomidine in Nerve-Intact and Baroreceptor-Denervated Rabbits

To determine the effects of intravenous dexmedetomidine (DMED) on the sympathetic nervous system and to elucidate the mechanism of hypotension, we administered 3 micro gram/kg of DMED to nerve-intact and baroreceptor-denervated rabbits and compared the changes in renal sympathetic nerve activity (RSNA) and hemodynamic variables. In nerve-intact animals, mean arterial pressure (MAP) was increased briefly and then decreased significantly. Changes in RSNA were reciprocal to those of MAP. Heart rate decreased throughout the period of observation. In baroreceptor-denervated rabbits, both MAP and RSNA decreased significantly (-39.4% +/- 3.8% and -21.3% +/- 4.7%, respectively) after the initial increase of MAP. Twenty minutes after administration, hypotension had still continued (-21.1% +/- 3.2%) although RSNA returned to the baseline value. These results indicate that suppression of sympathetic nerve discharge is indeed one of the mechanisms of DMED-induced hypotension, although it may not be the principal one. (Anesth Analg 1996;83:477-81)

Reliability of central venous pressure to assess left ventricular preload for fluid resuscitation in patients with septic shock

BackgroundInitial fluid resuscitation is an important hemodynamic therapy in patients with septic shock. The Surviving Sepsis Campaign Guidelines recommend fluid resuscitation with volume loading according to central venous pressure (CVP). However, patients with septic shock often develop a transient decrease in cardiac function; thus, it may be inappropriate to use CVP as a reliable marker for fluid management.MethodsWe evaluated 40 adult patients with septic shock secondary to intra-abdominal infection who received active treatment and were monitored using transthoracic echocardiography (TTE) and CVP for 2 days after admission to our intensive care unit (ICU). We measured left ventricular end-diastolic diameter (LVEDD), left atrial diameter (LAD), and the pressure gradient of tricuspid regurgitation (TR∆P). The shock status was treated with volume loading and inotrope/vasopressor administration according to the TTE findings. We assessed left ventricular fractional shortening (LVFS) as an index of left ventricular contractility and TR∆P as an index of right ventricular afterload and then examined the correlation between CVP and LVEDD/LAD/TR∆P.ResultsLVFS decreased to ≤30% in 42.5% and 27.5% of patients with septic shock, and severe left ventricular dysfunction with LVFS ≤20% developed in 12.5% and 15.0% of patients on the first and second ICU days, respectively, despite the use of inotropes/vasopressors. Mild pulmonary hypertension as indicated by TR∆P ≥30 mmHg was present in 27.5% and 30.0% of patients on their first and second ICU days, respectively. There was no significant correlation between CVP and LVEDD/LAD/TR∆P. The hospital mortality rate in this study was 10.0%, although the predicted mortality based on the Acute Physiology and Chronic Health Evaluation II score was 58.7%.ConclusionsOur results suggest that CVP is not a reliable marker of left ventricular preload for fluid management during the initial phase of septic shock. Assessment of left ventricular preload, right ventricular overload, and left ventricular contractility using TTE seems to be more informative than the measurement of CVP for fluid resuscitation since some patients developed left ventricular dysfunction and/or right ventricular overload.

Halothane augments the interaction between succinylcholine and pancuronium.

We previously reported that prior administration of succinylcholine prolonged the pancuronium-induced neuronmuscular block during halothane anesthesia [1]. Recent publications [2-3], however, have reported conflicting results in which the same dose of succinylcholine did not affect the duration of the pancuronium-induced neuromuscular block during neuroleptanesthesia. Therefore, it is possible that halothane may have affected our previous results. The present study was performed to investigate if halothane augments the interaction between succinylcholine and pancuronium. The Study was approved by the local Ethics Committee. Informed consent was obtained from 30 adult patients (ASA class I; aged 18-60 years), none of whom was taking medication or suffering from an illness known to affect neuromuscular function. All patients were premedicated with a combination of pethidine 1 mg.kg 1 and atropine 0.01 mg.kg <, i.m. 1 h before induction of anesthesia. They were randomly divided into groups of the same size according to the anesthetic agents used. The two groups were similar in age and weight. In the neuroleptanesthesia (NLA) group (n = 15), anesthesia was induced with droperidol 0.15 mg.kg -1, thiopental 2mg.kg -1, and fentanyl 45 ~g.kg -1, and the trachea was intubated with a cuffed tube facilitated by transtracheal administration of 4% lidocaine. Anesthesia was maintained with 60% nitrous oxide in oxygen with intermittent administration of thiopental and fentanyl. In the halothane group