Makoto Fukusaki

Symptoms of spinal stenosis do not improve after epidural steroid injection.

OBJECTIVE This study was carried out to evaluate the therapeutic effect of epidural steroid injection on pseudoclaudication in patients with lumbar degenerative spinal canal stenosis. DESIGN Fifty-three patients who complained of pseudoclaudication of less than 20 m in walking distance were randomly divided into three groups. Group 1 (n = 16) underwent epidural injection with 8 ml of saline. Group 2 (n = 18) underwent epidural block with 8 ml of 1% mepivacaine. Group 3 (n = 19) underwent epidural block with a combination of 8 ml of 1% mepivacaine and 40 mg of methylprednisolone. The criteria of evaluation were as follows: excellent effect, > 100 m in walking distance; good effect, 20-100 m in walking distance; poor effect, <20 m in walking distance. RESULTS In group 1, the numbers of patients who showed a good effect were two (12.5%) after 1 week, one (6.5%) after 1 month, and one (6.5%) after 3 months. In group 2, the numbers of patients who showed a good or excellent result were 10 (55.5%) after 1 week, three (16.7%) after 1 month, and one (5.6%) after 3 months. In group 3, the numbers of patients who showed a good or excellent result were 12 (63.2%) after 1 week, three (15.8%) after 1 month, and one (5.3%) after 3 months. There was no significant difference in the effectiveness of treatment between group 2 and group 3 throughout the time course. CONCLUSION The results suggest that epidural steroid injection has no beneficial effect on the pseudoclaudication associated with spinal canal stenosis as compared with epidural block with a local anesthetic alone.

Effects of sevoflurane with and without nitrous oxide on human cerebral circulation : Transcranial Doppler study

Background This study was designed to evaluate the effects of sevoflurane with and without nitrous oxide on human middle cerebral artery (MCA) flow velocity, cerebrovascular carbon dioxide reactivity, and autoregulation compared with the awake state using transcranial Doppler ultrasonography. Methods In 14 patients, the time‐mean middle cerebral artery flow velocity (Vmca) was measured when the end‐tidal carbon dioxide level was approximately 30, 40, and 50 mmHg under the following conditions: (1) awake; (2) with 2% (1.2 MAC) sevoflurane; and (3) with 1.2 MAC sevoflurane‐60% nitrous oxide. In six other patients, the cerebrovascular autoregulation during anesthesia was determined using intravenous phenylephrine to increase blood pressure. Results Sevoflurane (1.2 MAC) significantly decreased Vmca compared with the awake value at each level of end‐tidal carbon dioxide, whereas 1.2 MAC sevoflurane‐60% nitrous oxide did not exert significant influence. The Vmca in normocapnic patients decreased from 69 cm/s to 55 cm/s with 1.2 MAC sevoflurane and then increased to 70 cm/s when nitrous oxide was added. Sevoflurane (1.2 MAC) with and without 60% nitrous oxide had a negligible effect on cerebrovascular carbon dioxide reactivity. A phenylephrine‐induced increase of mean arterial pressure did not influence Vmca during anesthesia. Conclusions Sevoflurane (1.2 MAC) reduced Vmca compared with the awake condition, whereas the addition of nitrous oxide caused Vmca to increase toward the values obtained in the awake condition. The cerebrovascular carbon dioxide reactivity and autoregulation were well maintained during 1.2 MAC sevoflurane with and without 60% nitrous oxide.

Quantitative analysis of the relationship between sedation and resting energy expenditure in postoperative patients.

ObjectiveTo analyze quantitatively the relationship between sedation and resting energy expenditure or oxygen consumption in postoperative patients. DesignA prospective, clinical study. SettingAn eight-bed intensive care unit at a university hospital. PatientsThirty-two postoperative patients undergoing either esophagectomy or surgery of malignant tumors of the head and neck who required mechanical ventilation and sedation for ≥2 days postoperatively. InterventionsNone. Measurements and Main ResultsA total of 133 metabolic measurements were performed. Ramsay sedation scale (RSS), body temperature, and the dose of midazolam were evaluated at the time of the metabolic cart study. All patients received analgesia with buprenorphine at a fixed dose of 0.625 &mgr;g·kg−1·hr−1 continuously. Midazolam was used for induction and maintenance of intravenous sedation after admission to the intensive care unit. The initial dose was 0.04 mg·kg−1·hr−1 and was adjusted to achieve a desired depth of sedation at 3, 4, or 5 on the RSS every 4 hrs. The degree of sedation was classified into three states: light sedation (RSS 2–3; n = 49), moderate sedation (RSS 4; n = 39), and heavy sedation (RSS 5–6; n = 45). ResultsWith increasing the depth of sedation, oxygen consumption index (mL·min−1·m−2), resting energy expenditure index (REEI; kcal·day−1·m−2), and REE/basal energy expenditure (BEE) decreased significantly. Oxygen consumption index (mean ± sd), REEI, and REE/BEE were 151 ± 18, 1032 ± 120, and 1.29 ± 0.17 in the light sedation, 139 ± 22, 947 ± 143, and 1.20 ± 0.16 in the moderate sedation, and 125 ± 16, 865 ± 105, and 1.13 ± 0.12 in the heavy sedation, respectively. ConclusionAn increase in the depth of sedation progressively decreases in oxygen consumption index and REEI in postoperative patients.

The effects of propofol with and without ketamine on human cerebral blood flow velocity and CO2 response

UNLABELLED The combination of propofol and ketamine has been used for total IV anesthesia. This study was designed to clarify the effects of propofol-ketamine anesthesia on cerebral circulation by using transcranial Doppler ultrasonography. In Study 1, we examined the time course of time-mean middle cerebral artery blood flow velocity (Vmca) after ketamine (n = 10) or saline (n = 6) administration during propofol anesthesia. In Study 2, CO(2) responses were measured under the following conditions: awake (Group C, n = 7), propofol anesthesia (Group D, n = 7), and propofol-ketamine anesthesia (Group E, n = 8). Ketamine administration during propofol anesthesia administration did not affect Vmca, mean arterial pressure, or heart rate. Vmca under normocapnia in Groups D and E were 36 +/- 3 and 37 +/- 3 cm/s (mean +/- SE), respectively. The values were significantly lower than that of Group C (70 +/- 3 cm/s). The CO(2) response slopes of Groups D and E were significantly lower than that of Group C, although there was no significant difference between Groups D and E. These results suggest that ketamine does not influence Vmca or the cerebrovascular CO(2) response during propofol anesthesia administration, although the sample size in each group was small. IMPLICATIONS Our study suggests that ketamine does not influence middle cerebral artery blood flow velocity or the cerebrovascular CO(2) response assessed by transcranial Doppler ultrasonography during propofol anesthesia administration in patients without neurological complications.

Preoperative administration of intravenous flurbiprofen axetil reduces postoperative pain for spinal fusion surgery.

PurposeThe aim of the study was to investigate postoperative analgesia and the opioid-sparing effect of the preoperative administration of intravenous flurbiprofen axetil in patients undergoing spinal fusion surgery.MethodsThirty-six patients were randomly allocated into one of three groups. Group A received preoperative flurbiprofen axetil, 1 mg·kg−1. Group B received postoperative flurbiprofen axetil, 1 mg·kg−1. Group C received a placebo. All groups were given a standardized anesthesia and intravenous morphine via a patient-controlled analgesia device for postoperative analgesia. The pain score was evaluated by a visual analog scale (VAS) at 0 (T0), 1 (T1), 2 (T2), 6 (T3), 12 (T4), and 24 (T5) h after surgery, and the morphine requirement was recorded during the study period.ResultsVAS in group A was significantly lower than that in group B at T0 and T1. VAS in group A was significantly lower than that in group C throughout the time course after surgery. Postoperative morphine consumption in group A was significantly lower than that in groups B and C at T0 to T3.ConclusionAs compared with postoperative administration, preoperative administration of intravenous flurbiprofen axetil provides better postoperative analgesia and an opioid-sparing effect in patients undergoing spinal fusion surgery under general anesthesia.

Increased incidence of emergency airway management after combined anterior-posterior cervical spine surgery.

Among some kinds of cervical spine surgeries, combined anterior-posterior cervical spine surgery (CAP-CS surgery) requires prolonged operative time and highly invasive procedure. This study was performed to determine whether CAP-CS surgery was associated with increased risk of emergency airway management compared with other cervical spine surgeries (O-CS surgeries). The records of the patients who underwent cervical spine surgery between July 2001 and March 2003 at our institution were reviewed retrospectively, and we determined whether the CAP-CS surgery was associated with an increased risk of emergency airway management in comparison with O-CS surgeries, using the logistic regression analysis. A total of 165 were eligible for inclusion in the study. A total of 127, 20, 11, 5, and 2 patients suffered from cervical myelopathy, traumatic cervical spinal cord injury, atlantoaxial dislocation, cervical spinal tumors, and cervical pyogenic spondylitis, respectively. The operative approaches were CAP-CS surgery, anterior surgery, posterior surgery, and atlantoaxial surgery in 10, 56, 88, and 11 patients, respectively. Thus, the operative approaches were CAP-CS surgery in 10 patients and O-CS surgeries in 155 patients. Postoperative emergency airway management was required in 7 of the 10 patients (70%) who underwent CAP-CS surgery, and 2 of the 155 patients (1%) who underwent O-CS surgeries. The increased risk of postoperative emergency airway management imposed by CAP-CS surgery was 178.5 by an odds ratio, with a 95% confidence interval of 25.6 to 1246. The results show that CAP-CS surgery provides a major risk factor for postoperative emergency airway management.

Sevoflurane protects stunned myocardium through activation of mitochondrial ATP-sensitive potassium channels

We sought to determine the hemodynamic and cardioprotective effects of sevoflurane in canine stunned myocardium. Forty-nine dogs were allocated to one of seven groups (n = 7 for each). In six separate groups, dogs received vehicle, glibenclamide (a nonselective adenosine triphosphate-dependent potassium [KATP] channel antagonist) (0.3 mg/kg IV) or 5-hydroxydecanoic acid (a mitochondrial KATP channel antagonist) (5 mg/kg IV) in the presence or absence of 1 minimum alveolar concentration (1 MAC) sevoflurane. In an additional group, dogs received 1 MAC sevoflurane with hemodynamic correction. Regional myocardial contractility was evaluated with segment shortening. Measurements were made before and during 15-min ischemia and 90-min reperfusion. Recovery of segment shortening 90 min after reperfusion was significantly improved in the dogs anesthetized with sevoflurane either with or without hemodynamic correction (70.1 ± 4.2 and 75.9 ± 3.1% of baseline, respectively), whereas the recovery was poor in control and glibenclamide or 5-hydroxydecanoic acid pretreated dogs (33.3 ± 4.3, 33.8 ± 6.8, and 45.0 ± 5.5% of baseline, respectively). Regional myocardial perfusion showed no significant difference among groups. The results indicate that sevoflurane has a cardioprotective effect mediated through activation of mitochondrial KATP channels and independent of coronary blood flow or reduction in cardiac work.

Sequential use of midazolam and propofol for long-term sedation in postoperative mechanically ventilated patients.

Acute withdrawal syndromes, including agitation and a long weaning time, are common adverse effects after long-term sedation with midazolam. We performed this study to determine whether the sequential use of midazolam and propofol could reduce adverse effects as compared with midazolam alone. We studied 26 patients receiving mechanical ventilation for three or more days after surgery. Patients were randomly assigned to two groups. In Group M, patients were sedated with midazolam alone. In Group M-P, midazolam was switched to propofol approximately 24 h before the expected stopping of sedation. The level of sedation was maintained at 4 or 5 on the Ramsay sedation scale. The sedation agitation scale was evaluated for 24 h after extubation. The recovery time from stopping of sedation to extubation was significantly shorter in Group M-P (1.3 ± 0.4 h) compared with Group M (4.0 ± 2.4 h). The incidence of agitation in Group M-P (8%) was significantly less frequent than that in Group M (54%). The results indicate that sequential use of midazolam and propofol for long-term sedation could reduce the incidence of agitation compared with midazolam alone.

Renal function in patients during and after hypotensive anesthesia with sevoflurane

STUDY OBJECTIVES To evaluate renal function during and after hypotensive anesthesia with sevoflurane compared with isoflurane in the clinical setting. DESIGN Randomized, prospective study. SETTING Inpatient surgery at Rosai Hospital. PATIENTS 26 ASA physical status I and II patients scheduled for orthopedic surgery. INTERVENTIONS Patients received isoflurane, nitrous oxide (N2O), and fentanyl (Group I = isoflurane group; n = 13) or sevoflurane, N2O, and fentanyl (Group S = sevoflurane group; n = 13). Controlled hypotension was induced with either isoflurane or sevoflurane to maintain mean arterial pressure at 60 mmHg for 120 minutes. MEASUREMENTS AND MAIN RESULTS Measurements included serum inorganic fluoride (previously speculated to influence renal function), creatinine clearance (CCr; to assess renal glomerular function), urinary N-acetyl-beta-D-glucosaminidase (NAG; to assess renal tubular function), blood urea nitrogen (BUN), and serum creatinine (as clinical renal function indices). Serum fluoride, CCr, and NAG were measured before hypotension, 60 minutes, and 120 minutes after the start of hypotension, 30 minutes after recovery of normotension, and on the first postoperative day. BUN and serum creatinine were measured preoperatively and on the third and seventh postoperative days. Minimum alveolar concentration times hour was 3.6 +/- 1.8 in Group I and 4.0 +/- 0.7 in Group S. In both groups, BUN and serum creatinine did not change, and CCr significantly decreased after the start of hypotension. In Group I, serum fluoride and NAG did not change. In Group S, serum fluoride significantly increased after the start of hypotension compared with prehypotension values and compared with Group I values. In addition, NAG significantly increased at 120 minutes after the start of hypotension and at 30 minutes after recovery of normotension, but returned to prehypotension values on the first postoperative day. CONCLUSIONS Two hours of hypotensive anesthesia with sevoflurane under 5 L/min total gas flow in patients having no preoperative renal dysfunction transiently increased NAG, which is consistent with a temporary, reversible disturbance of renal tubular function.

Influence of low-molecular-weight hydroxyethyl starch on microvascular permeability in patients undergoing abdominal surgery : comparison with crystalloid

PurposeAdequate volume therapy is essential for stable hemodynamics and sufficient urinary output perioperatively. Hydroxyethyl starch (HES) has been reported to attenuate the microvascular hyperpermeability which occasionally occurs in surgical patients. This study was carried out to evaluate the effect of low-molecular-weight HES on the urinary microalbumin/creatinine ratio (MACR), a marker of microvascular permeability, in surgical patients.MethodsIn a prospective, controlled, and randomized clinical trial, 21 patients undergoing abdominal surgery were divided into two groups. Group HES (n = 10) received HES at 2 ml·kg−1·h−1 during surgery and at 1 ml·kg−1·h−1 after surgery, and additionally they received acetated Ringer’s solution (AR) at a rate to keep central venous pressure (CVP) 5 mm Hg. Group AR (n = 11) received AR at a rate to keep CVP at 3–5 mmHg. MACR, soluble intercellular adhesion molecule-1 (sICAM-1), and urinary output were measured intermittently in the perioperative period.ResultsMACR was significantly increased during surgery in both groups. There was no significant difference in MACR between the two groups throughout the study period. The serum concentration of sICAM-1 decreased during surgery in both groups, and that in group HES was significantly lower than that in group AR at the end of surgery. Postoperative urinary output in group HES was greater than that in group AR. The intensive care unit (ICU) stay in group HES was shorter than that in group AR.ConclusionAlthough low-molecular-weight HES does not improve microvascular hyperpermeability, the expansion of the intravascular volume by HES results in higher urinary output in the postoperative period than that seen with crystalloid solution. The lower concentration of sICAM-1 after surgery may be due to hemodilution.