Quantitative Sensory Testing in pain assesment and treatment. Brief review and algorithmic management proposal

Quantitative Sensory Testing (QST) is used to globally analyze the nociceptive system in order to obtain a more objective understanding of pain perception. In recent years, QST has become a common tool in many pain clinics and anesthesiology departments worldwide. In 2013, the Neuropathic Pain Special Interest Group of the IASP put forward the first recommendations for conducting QST in clinical practice and research. However, the wide variety of QST methodologies and standards in the literature make it difficult to generalize the used of this tool in clinical practice. In this study, we present the basic concepts of QST, the type of tests and devices used, how they are applied, and the role of QST in anesthesiology and pain management.

[Epiduroscopy]

Epiduroscopy is a minimally invasive diagnostic and therapeutic technique used in patients with chronic low back pain with or without radiculopathy. Epiduroscopic procedures are particularly indicated in cases of failed spinal surgery. This review discusses the indications, contraindications, and complications of the technique, describing in detail the sacral (caudal) and interlaminar approaches and noting their advantages and disadvantages. Practical recommendations are made, along with an attempt to assess future prospects for epiduroscopy.

Interlaminar approach for epiduroscopy in patients with failed back surgery syndrome

BACKGROUND

Epiduroscopy is a relatively new diagnostic and therapeutic technique used in patients with chronic low back pain with or without radiculopathy. We present our experience with a new interlaminar approach in patients with failed back surgery syndrome (FBSS).

METHODS

Patients with severe symptoms of FBSS who did not respond to other treatments were included. Lumbar epiduroscopy was performed via interlaminar approach through a 14 G epidural needle under fluoroscopy. A flexible, 0.77 mm, endoscope was introduced through a 4F catheter into the epidural space and advanced in a cephalad direction. Flushes of normal saline through the catheter (via a Y-adapter/haemostasis valve) enabled distension of the space. Adhesions were mechanically mobilized under direct vision. A mixture of triamcinolone 60 mg, hyaluronidase 600 IU, and bupivacaine 0.0625% was instilled.

RESULTS

Nineteen patients were included. The mean number of operations at lumbar level was 2.26. Major findings included adhesions, inflammation, stenosis, and nerve root hypotrophia. The visual analogue scale (VAS) score was 7.89 at baseline, 5.95 (P<0.001) 3 months later, and 6.05 (P<0.001) 6 months later. Six patients (31.6%) did not show any improvement, and six other patients showed a very significant improvement (at least three points reduction in the VAS) 3 months later. We had four cases of dural puncture, but only one patient required hospital admission.

CONCLUSIONS

We have described a new procedure for epiduroscopy with approximately 50% reduced outer diameter of the catheter, which allows interlaminar approach. Its diagnostic efficacy is clear and there were a significant number of patients who had improved outcome.

Trigeminal nerve palsy and Horner’s syndrome following epidural analgesia for labor: a subdural block?

Horner's syndrome is a rare complication of epidural analgesia for labor. Much more uncommon is trigeminal nerve palsy. Both complications may be attributed to a subdural localization of the catheter, as we demonstrated clinically by a repeat injection and patchy sympathetic block and with the typical image on epidurography.

Bolus application of remifentanil with propofol for dilatation and curettage

BACKGROUND AND OBJECTIVE

This study was designed to determine which single bolus dose of remifentanil in combination with propofol and nitrous oxide is best to control the haemodynamic, autonomous and somatic responses in patients scheduled for dilatation and curettage of the uterine cervix. We evaluated the adequacy of different bolus doses of remifentanil, associated with propofol and nitrous oxide, for dilatation and curettage in a prospective double-blind study.

METHODS

After institutional approval and informed consent, 34 healthy females undergoing curettage to remove material from the uterus after spontaneous abortion were randomized to receive remifentanil 0.5 microg kg(-1) intravenously (i.v.) (Group A; n = 4), 1 microg kg(-1) i.v. (Group B; n = 15) or 1.5 microg kg(-1) i.v. (Group C; n = 15), with propofol 2 mg kg (-1) i.v. in all groups. Anaesthesia was maintained with 60% nitrous oxide in oxygen. Haemodynamic, somatic and autonomic signs of light anaesthesia were registered to assess the response to surgical stress. Recovery times and Aldrete score were recorded at the end of the procedure.

RESULTS

The groups were similar with regard to biometric data and duration of surgery. The poor results using the lowest dose of remifentanil obliged us to abandon this dose. The total dose of remifentanil was larger in Group C (100 +/- 5.7 microg vs. 65 +/- 4.1 microg in Group B; P < 0.05), but more patients required extra bolus injections in Group B (69% vs. 38% in Group C; P < 0.01). Recovery times were significantly shorter in Group C. Aldrete scores when leaving the operation room was similar.

CONCLUSIONS

Remifentanil 1.5 microg kg(-1) i.v. with propofol 2 mg kg(-1) i.v. and 60% nitrous oxide in oxygen provided the best anaesthetic control with the fastest recovery times.

Cardiopulmonary resuscitation training for students of odontology: skills acquisition after two periods of learning

INTRODUCTION

Although life threatening emergencies in dental practice are not frequent, dentists have to be competent in providing basic life support (BLS).

OBJECTIVES

The aim of this work was to study the level of skills acquisition among dentistry students in two different periods of one rescuer-BLS training, a first short practice training of 2 h followed by 8 h of practice over a period of 2 months.

METHODS

One hundred and sixteen second-year undergraduate students of Anesthesiology at the Dental School of the Complutense University in Madrid were tested at the end of the two periods of learning using a recording manikin with a validated scoring system (Laerdal Resusci-Anne). This manikin recorded the percentage of adequate chest compressions and insuflations, rate of chest compressions and the causes of error in each case.

RESULTS

Final global results were, 51.66+/-3.0% adequate chest compressions; and 54.44+/-3.61% adequate insuflations. The kinds of errors where different in both tests were, wrong hand position (26.92+/-2.96 vs. 12.29+/-2.40%, P<0.001); excessive compressions (27.71+/-2.90 vs. 16.02+/-2.33%, P<0.05); and weak compressions (23.28+/-3.24 vs. 16.77+/-2.57%, P<0.05). Regression analysis found a positive correlation among excessive compression, height and weight (P<0.001) and a negative correlation between weak compression, height and weight (P<0.001).

CONCLUSIONS

The poor overall results, although similar to those shown in the literature, have made us question the validity of our methods of teaching BLS. We were able to establish a correlation between demographic and sociocultural variables with the typical errors, and to begin the process of improving our teaching methods.

Continuous monitoring of oesophageal pH during general anaesthesia with laryngeal mask airway in children

We studied the incidence of gastro-oesophageal reflux (GOR) during general anaesthesia with the laryngeal mask airway (LMA) in a paediatric population with two ventilatory regimes: spontaneous breathing and controlled mechanical ventilation (CMV). Thirty children between 6 months and 15 years, ASA I-II, for routine surgery, were randomly assigned in two groups: spontaneous ventilation (n=14), and CMV (n=16). A pH probe was situated in the central third of the oesophagus. Some 66% of the patients breathing spontaneously had GOR episodes vs. 92% of the patients with CMV (P < 0,01). Reflux took place mainly after LMA removal (21% vs. 68%; P < 0,01) and in the Postanaesthetic Care Unit (PACU) (29% vs. 43%; P < 0,05). There was a high incidence of GOR during general anaesthesia and in the PACU in paediatric patients anaesthetized with the LMA. GOR episodes were significantly more evident in the CMV group, mainly after LMA removal, but without clinical significance.

Fatal paradoxical air embolism during liver transplantation

We describe a case of fatal paradoxical coronary air embolism during liver transplantation. The literature on the diagnosis and prophylaxis of paradoxical air embolism during liver transplantation is reviewed and discussed.

Presence of a nitric oxide synthase inhibitor in the graft efflux during reperfusion in human liver transplantation

Involvement of the nitric oxide (NO) system in complications following human orthotopic liver transplants (OLT) has been reported, but the contribution of the graft to the modulation of the NO system during reperfusion in normal OLT has not been characterized. We have studied the contribution of the graft efflux to the modulation of the NO system in 20 consecutive OLT. We evaluated its effects on isolated vascular reactivity of the rabbit and on rat cultured macrophages stimulated with lipopolysaccharide (LPS). In none of the donor liver biopsies was expression of inducible NO synthase (iNOS) activity by Northern or Western blot analysis found. Graft efflux after the onset of liver reperfusion, but not pre-transplant patient plasma, reversibly inhibited the acetylcholine-induced relaxation of norepinephrine-contracted rabbit aortic rings. Moreover, graft efflux reversibly inhibited NO production in rat macrophages treated with LPS, as evidenced by both a decrease in nitrite plus nitrate formation and a decrease in the production of [14C]citrulline from [14C]arginine. Addition of a 10% dilution of graft efflux to cultured rat macrophages incubated with LPS increased iNOS mRNA levels, suggesting direct inhibition of the enzyme but not of its expression. These results cannot be ascribed to the depletion of arginine the iNOS substrate since they can be reproduced even in the presence of an excess (10 mM) of exogenously added arginine. No correlation was found between the iNOS inhibitory activity in each sample and the corresponding clinical parameters related to either the graft function after the OLT or the existence of post-reperfusion syndrome. Our results indicate the existence of a soluble factor in the graft efflux from human OLT that reversibly and unspecifically inhibits NOS activity. Its involvement in the physiology and/or pathology of human liver diseases deserves further study.

Protective effects of cyclopiazonic acid on ischemia-reperfusion injury in rabbit hearts

The cardioprotective effects on myocardial ischemia of the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA) inhibitor, cyclopiazonic acid (CPA), were studied. We used the isolated arterially perfused interventricular septum of the rabbit heart submitted to 30-min global ischemia/30-min reperfusion. Mechanical [maximal increase in resting tension (MIRT), and the recovery of developed tension (RDT)], and biochemical parameters [creatine phosphokinase activity (CPK) in the effluent] were analyzed. CPA, 1 microM, perfused 30 min before the ischemia intervention significantly increased RDT by 54% and lessened MIRT by 66%. CPA also decreased CPK in the perfusate by 67.7 and 71.4% at 0-2 and 5-7 min of reperfusion, respectively. No additional benefits were shown either when the drug was perfused, both during ischemia and reperfusion, or with higher CPA concentrations (10-30 microM). The CPA cardioprotection was lost when the drug was present only during the reperfusion period. CPA exhibits functional and biochemical cardioprotective effects on myocardial ischemia. We postulated a decreased SR calcium contribution to the initial cytoplasmic calcium overload as the most probable mechanism involved.

Pourfour du Petit syndrome: a case following a traffic accident with severe cranioencephalic trauma

Poufour du Petit syndrome is an extraordinarily unusual clinical condition produced by hyperactivity of the sympathetic cervical chain as a consequence of irritation of these nerves. It causes an ipsilateral mydriasis, which, in patients suffering a head injury as in the case reported here, can confuse the diagnosis and disconcert physicians.