Level of consciousness affects the excitability of spinal motor neurones during propofol sedation in humans

Clinical and electrophysiological features of acute flaccid myelitis: A national cohort study

OBJECTIVE

To summarize the neurophysiological properties of acute flaccid myelitis (AFM) and evaluate limb-based motor outcomes.

METHODS

Nerve conduction studies (NCS) in 49 patients (21 females, 28 males; median age = 52 m) with AFM (median = 7 d after onset; range 1-122 d) were reviewed. Neurophysiological findings, together with treatment and prognosis, and neurophysiology-neuroimaging correlations were analyzed.

RESULTS

The findings indicated that 64% of paralytic limbs during the acute stage (≤14 d after onset) showed diminished or absent compound muscle action potentials (CMAPs), 79% showed normal motor nerve conduction velocities, 55% showed decreased persistence or absent F-waves, and 95% showed normal sensory nerve conduction velocities. The rate of CMAP abnormalities increased from 41% on days 1-2 to 83% on days 13-14. The reduction in CMAP amplitude was correlated with weaker muscle strength at both the peak neurological deficit and the last follow-up. The baseline limb-based muscle strength at nadir and anterior horn-localized magnetic resonance imaging lesions at recovery stage (>14 d) were strong predictors of outcome at the last follow-up.

CONCLUSIONS

AFM typically shows neurophysiological features of neuronopathy.

SIGNIFICANCE

NCS is probably useful in the diagnosis and evaluation of AFM.

Demonstration of analgesic effect of intranasal ketamine and intranasal fentanyl for postoperative pain after pediatric tonsillectomy

OBJECTIVE

Tonsillectomy is one of the oldest and most commonly performed surgical procedure in otolaryngology. Postoperative pain management is still an unsolved problem. In this study, our aim is to demonstrate the efficacy of intranasal ketamine and intranasal fentanyl for postoperative pain relief after tonsillectomy in children.

MATERIAL AND METHOD

This randomized-controlled study was conducted to evaluate the effects of intranasal ketamine and intranasal fentanyl in children undergoing tonsillectomy. Tonsillectomy performed in 63 children were randomized into three groups. Group I received: Intravenous paracetamol (10 mg/kg), Group II received intranasal ketamine (1.5 mg/kg ketamine), Group III received intranasal fentanyl (1.5 mcg/kg). The Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and Wilson sedation scale scores were recorded at 15, 30, 60 min, 2 h, 6hr, 12 h and 24 h postoperatively. Patients were interviewed on the day after surgery to assess the postoperative pain, nightmares, hallucinations, nausea, vomiting and bleeding.

RESULTS

Intranasal ketamine and intranasal fentanyl provided significantly stronger analgesic affects compared to intravenous paracetamol administration at postoperative 15, 30, 60 min and at 2, 6, 12 and 24 h in CHEOPS (p < 0.05). Sedative effects were observed in three patients in the intranasal ketamine administration group. No such sedative effect was seen in the groups that received intranasal fentanyl and intravenous paracetamol in Wilson Sedation Scale (p < 0.05). Cognitive impairment, constipation, nausea, vomiting and bleeding were not observed in any of the groups.

CONCLUSION

This study showed that either intranasal ketamine and intranasal fentanyl were more effective than paracetamol for postoperative analgesia after pediatric tonsillectomy. Sedative effects were observed in three patients with the group of intranasal ketamine. There was no significant difference in the efficacy of IN Ketamine and IN Fentanyl for post-tonsillectomy pain.

A randomized study of surgical site infiltration with bupivacaine or ketamine for pain relief in children following cleft palate repair

BACKGROUND

Wound infiltration with ketamine reduces postoperative pain after tonsillectomy by NMDA receptor blockade and local anesthetic effect.

OBJECTIVES

To evaluate the postoperative analgesia after surgical site infiltration with bupivacaine or ketamine in children undergoing cleft palate surgery.

MATERIALS AND METHODS

After institutional ethics committee approval and parental consent, 50 ASA-1 children of age 1-6 years undergoing palatoplasty were included in this prospective randomized double-blind study. A standardized technique of general anesthesia was used. The surgical site was infiltrated with either 2 mg·kg(-1) of bupivacaine (Group B) or 0.5 mg·kg(-1) of ketamine (Group K). Pain (Children Hospital Eastern Ontario Pain Score), sedation, dysphagia, nausea, vomiting, and sleep pattern were assessed postoperatively up to 24 h.

RESULTS

CHEOPS scores were similar in both the groups up to 12 h but were lower with ketamine compared with bupivacaine at 24 h postoperatively (P = 0.01). Fewer children required rescue analgesics in Group K (28%) than in Group B (64%; P < 0.01). The time to first rescue analgesic and the amount of analgesics used in 24 h were similar in the two groups. Fewer children suffered from dysphagia in Group K (52%) than in Group B (88%; P < 0.01). More children in Group B had disturbed sleep than in Group K at 6 (88% vs 56%; P = 0.012) and 12 h (60% vs 24%; P = 0.01) postoperatively. None of the children had deep sedation, desaturation or respiratory depression.

CONCLUSION

Surgical site infiltration with either bupivacaine or ketamine provides adequate analgesia and is devoid of major side effects. Ketamine is superior to bupivacaine in terms of requirement of rescue analgesic, peaceful sleep pattern and early resumption of feeding.

Association between bispectral index and age and use of sedative drugs in high spinal anaesthesia

OBJECTIVES

A prospective, randomized, double-blind study using bispectral index values to objectively quantify the sedative effect of high spinal anaesthesia in patients stratified according to age, and to determine whether sedative drugs are associated with additional adverse respiratory and haemodynamic effects in older patients.

METHODS

Patients who were electively scheduled for lower limb or abdominal surgery were recruited and allocated into one of three groups according to their age and whether midazolam and fentanyl were used: younger (20-40 years); and older (61-80 years) with or without midazolam and fentanyl intravenous infusion.

RESULTS

The study recruited a total of 90 patients (n = 30 per group). Intraoperative bispectral index values were significantly lower than preoperative values in all groups. Patients in the older age group had significantly lower intraoperative bispectral index values than younger patients. Older patients were significantly more likely to experience respiratory depression (arterial oxyhaemoglobin saturation <90%) than younger patients.

CONCLUSIONS

The sedative effect of high spinal anaesthesia is greater in older patients than in younger patients, with an increase in respiratory instability.

The preventative analgesic effect of preincisional peritonsillar infiltration of two low doses of ketamine for postoperative pain relief in children following adenotonsillectomy. A randomized, double-blind, placebo-controlled study

BACKGROUND

In literature, the use of ketamine for the preventative analgesia in the management of postoperative pain is controversial. The purpose of the present study was the clinical assessment of the efficacy of preincisional peritonsillar infiltration of two doses of ketamine on postoperative pain relief compared with peritonsillar saline in children undergoing adenotonsillectomy.

METHODS/MATERIALS

Seventy-five ASA physical status I and II patients, aged 3-12 years, scheduled for adenotonsillectomy were enrolled in this randomized, double-blind, placebo-controlled study. Patients were divided into three groups of 25 each and received a local peritonsillar infiltration of 0.9% saline (group S), ketamine 0.5 mg x kg(-1) (group K1), or ketamine 1 mg x kg(-1) (group K2). All medications were 2 ml in volume which was applied 1 ml per tonsil 3 min prior to tonsillectomy. The Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) and Wilson sedation scale were used to evaluate pain levels and sedative conditions, respectively.

RESULTS

Group S had significantly higher CHEOPS scores than group K1 and K2. Both K1 and K2 groups had comparable scores, which were not statistically significant (P > 0.05). During 24 h after surgery, 16 patients in group S and no patients in groups K1 or K2 needed analgesics (P < 0.001).

CONCLUSIONS

A 0.5 or 1 mg.kg(-1) dose of ketamine given at approximately 3 min before surgery by peritonsillar infiltration provides efficient pain relief during 24 h after surgery without side-effects in children undergoing adenotonsillectomy.

Multi-level approach to anaesthetic effects produced by sevoflurane or propofol in humans: 2. BIS and tetanic stimulus-induced withdrawal reflex †

BACKGROUND

General anaesthesia could be assessed at two sites: cortical structures and the spinal cord. However, the practicalities of measurement at these two sites differ substantially.

METHODS

We simultaneously analysed effects of sevoflurane (Group S; n = 16) or propofol (Group P; n = 17) on bispectral index (BIS) and the tetanic stimulus-induced withdrawal reflex (TIWR). TIWR was quantified by the area under the curve of the electromyogram of the biceps femoris muscle after electrical stimulation of the sural nerve. After loss of consciousness, TIWR was evoked once per minute. The anaesthetic was increased until TIWR disappeared. After discontinuation of the anaesthetic and reappearance of TIWR, the amount of anaesthetic was increased again. Using a sigmoid E(max) model and a first-order rate constant k(e0), we characterized the dose-response relationships for BIS and TIWR.

RESULTS

Concentration-dependent depression of TIWR was reasonably well modelled for sevoflurane, but poorly for propofol. TIWR was completely suppressed by sevoflurane, but not propofol. Sevoflurane reduced TIWR to 5 mV ms (very weak movement) at 1.68 vol% end-expired concentration [approximately minimum alveolar concentration (MAC value)]. The k(e0)s for TIWR were smaller than those for BIS: 0.25 (0.16-0.39) vs 0.41 (0.33-0.51) min(-1) for Group S; 0.25 (0.22-0.30) vs 0.34 (0.29-0.40) min(-1) for Group P [geometric mean (95% CI)].

CONCLUSIONS

High concentrations of sevoflurane depress TIWR more than propofol. With propofol, we frequently observed a paradoxical behaviour of muscles of the lower leg. TIWR lags behind BIS, indicating different effect sites for two intended anaesthetic effects: unresponsiveness to noxious stimulation and unconsciousness.

Ketamine in post-tonsillectomy pain

OBJECTIVE

There has yet been no ideal method for postoperative analgesia in children. Ketamine demonstrates a potent analgesic effect by central blockage of perception of pain with sub-anesthetic doses. Preoperative intramuscular administration of ketamine for sedation decreases the pain during swallowing after tonsillectomy, while it provides long-term analgesia when applied around the incision. The aim of this study is to compare the effectiveness of ketamine administered to the tonsillar region following tonsillectomy for postoperative pain management.

METHODS

After obtaining consent from the local ethics committee and the parents, 60 patients from the ASA groups I and II, between 3 and 7 years of age, planned for adenotonsillectomy as outpatients, were included in the study. Subjects were randomly assigned to two equal groups and 2ml 0.9% saline for group S, and 0.5mgkg(-1) ketamine and saline 2ml in volume for group K were administered into the tonsillar region. All subjects were monitored in a standard manner and SpO(2), systolic arterial pressure (SAP), and cardiac pulse rates were recorded in 5min intervals. The CHEOPS and Wilson sedation scale were used to evaluate pain levels and sedative condition, respectively. Nausea and vomiting scores of the subjects were also noted. The time of the first analgesic administration and the total amount of analgesics in an 8-hour period were recorded. Student-T and Chi-Square tests were used for the statistical evaluation of the data and a p value of <0.05 was accepted as significant.

RESULTS

There were no significant differences between groups according to age, sex, weight, intermittent SAP and cardiac pulse rates. However, the CHEOPS value, the first analgesic need and the total amount of analgesic need were in favor of ketamine (p<0.05).

CONCLUSIONS

In previous studies, no significant differences were demonstrated in pre-emptive analgesia with ketamine, magnesium, morphine, and clonidine. The dose of ketamin and the volume used in this study caused no sedation or nausea and provided a high level of analgesia. Ketamine infiltration into the tonsillar region after tonsillectomy was found to be easy and effective.

Influence of the baricity of a local anaesthetic agent on sedation with propofol during spinal anaesthesia

BACKGROUND

This study examined the effect of different levels of spinal anaesthesia, induced by solutions of different baricity but containing the same amount of local anaesthetic agent, on the requirement for sedation with propofol.

METHODS

Thirty-six patients undergoing varicose vein surgery under spinal anaesthesia were randomly allocated to receive tetracaine 15 mg in 3 ml of either glucose 5% (hyperbaric) or CSF (isobaric). I.V. propofol was started 5 min after the intrathecal injection and was titrated to maintain a bispectral index (BIS) score of 65-75. The propofol requirements to maintain this range in the two groups were compared every 5 min.

RESULTS

The propofol requirement was always lower in the hyperbaric group, with the differences becoming statistically significant 20 min after the intrathecal injection. Total consumption of propofol over the 55 min of the study was also less in the hyperbaric group.

CONCLUSION

The known difference in level of spinal anaesthetic block induced by solutions of different baricity, but the same dose of local anaesthetic, was associated with different requirements for propofol sedation as determined by BIS assessment.