The perioperative combination of methadone and ketamine reduces post-operative opioid usage compared with methadone alone.

BACKGROUND: A synergy between ketamine and methadone (ME) to produce antinociception has been demonstrated in experimental neuropathy. We wanted to compare post-operative opioid requirements in patients undergoing multilevel lumbar arthrodesis after the administration combined ME-ketamine (MK) or ME alone. METHODS: This was a randomised double-blind study. During sevoflurane-remifentanil anaesthesia, 11 patients in each group received the following: ketamine bolus (0.5 mg/kg) after tracheal intubation, followed by an infusion of 2.5 µg/kg/min in the MK or saline bolus plus infusion in the ME group. Post-operative analgesia - during 48 h - was provided by patient-controlled analgesia (PCA), delivering bolus containing the following: ME 0.25 mg plus ketamine 0.5 mg in the MK group or ME 0.5 mg in the ME group. Lockout was 10 min, maximum of 3 boluses/h in both groups. Before closing the wound, all the patients received intravenous (i.v.) ME 0.1 mg/kg, dexketoprophen and paracetamol. Pain intensity was evaluated by a numerical rating scale (NRS), on arrival at recovery room (RR) and 24 and 48 h after surgery. In the RR, i.v. ME was administered until NRS was 3 when PCA was started. Dexketoprophen and paracetamol were administered 48 h. RESULTS: Remifentanil requirements were higher in the MK group (P = 0.004). Patients in the MK group received 70% less ME by PCA at 24 h (MK vs. ME group, median and interquartile range) - 3.43 mg (1.9-6.5) vs. 15 mg (9.65-17.38) (P < 0.001) - and at 48 h - 2 mg (0.5-3.63) vs. 9.5 mg (3.5-13.75) (P = 0.001). Patients in the MK group also attempted less doses, at 24 h: 19.5 (12.75-79.5) vs. 98 (41.5-137) (P = 0.043). Both groups had similar NRS values and comparable side effects. CONCLUSIONS: Perioperative ketamine-ME combination significantly decreased opioid consumption by PCA.

Dexmedetomidine in difficult airway management with a fibre-optic bronchoscope in the awake patient with Klippel-Feil Syndrome. / Dexmedetomidina en el manejo de la vía aérea difícil con fibrobroncoscopio en paciente despierto afecto de síndrome de Klippel-Feil.

Klippel-Feil Syndrome is a disease characterised by congenital fusion of cervical vertebra, which leads to cervical limitation and instability. In these cases, the best option is the orotracheal intubation with the fibre-optic bronchoscope with the patient awake. The advantage is that cervical movements that could lead to neurological damage are minimised. In these patients, adequate sedation, together with instillation of local anaesthetic in the pharynx and hypopharynx, is the key to reducing patient discomfort and achieving successful orotracheal intubation. Dexmedetomidine is a selective α2- adrenergic receptor agonist that produces sedation and analgesia at the locus coeruleus without producing respiratory depression, as well as maintaining patient collaboration. The case is presented of a patient with Klippel-Feil Syndrome and difficult airway management, who was given a dexmedetomidine infusion at 0.6µg/kg/h as sedation for an awake fibre-optic endotracheal intubation.

Density spectral array of BIS VISTA™ monitoring system in a functional hemispherectomy. / Monitorización con espectrograma del sistema de monitorización BIS VISTA™ en una hemisferectomía funcional.

We present the case of an adult patient with drug-resistant epilepsy caused by extensive inflammation in the right cerebral hemisphere. She was scheduled to undergo right functional hemispherectomy, which is common in pediatric surgery, but about which few studies have been published with respect to adult patients. During the intraoperative period, the density spectral array of the bilateral bispectral index (BIS) VISTATM monitoring system was used. We observed a power increase in low frequency (0.1-4Hz) and alpha bands (8-12Hz) in the right hemisphere, where the epileptogenic focus was. During disconnection from the frontal lobe, there was a marked decrease of power in low frequency and alpha bands on the right side, with no changes during disconnection from other areas of the brain. We think that further studies are needed to determine whether the density spectral array can be a useful tool for monitoring the effectiveness of functional hemispherectomy.

Anaesthesia management in epilepsy surgery with intraoperative electrocorticography. / Manejo anestésico en la cirugía de epilepsia con electrocorticografía intraoperatoria.

Epilepsy surgery is a well-established treatment for patients with drug-resistant epilepsy. The success of surgery depends on precise presurgical localisation of the epileptogenic zone. There are different techniques to determine its location and extension. Despite the improvements in non-invasive diagnostic tests, in patients for whom these tests are inconclusive, invasive techniques such intraoperative electrocorticography will be needed. Intraoperative electrocorticography is used to guide surgical resection of the epileptogenic lesion and to verify that the resection has been completed. However, it can be affected by some of the anaesthetic drugs used by the anaesthesiologist. Our objective with this case is to review which drugs can be used in epilepsy surgery with intraoperative electrocorticography.

[Utility of monitoring with the PiCCO system during lung resection surgery]. / Utilidad de la monitorización con sistema PiCCO durante cirugía de resección pulmonar.

OBJECTIVES: To evaluate the practical utility of the PiCCO system for monitoring cardiac output and its derived variables during lung resection surgery. PATIENTS AND METHODS: Patients scheduled for lung resection surgery were enrolled. After anesthesia had been induced, a Pulsiocath catheter was placed in the femoral artery ipsilateral to the thoracotomy. The following parameters were evaluated: ease of placement of the arterial catheter, functioning of the system, and appearance of complications. When the catheter was connected to the PiCCO monitor, cardiac output and derived variables were recorded throughout the procedure. RESULTS: Fifteen patients were enrolled in the study. Placement of the catheter in the femoral artery was easy in 9 cases (60%), difficult in 4 cases (27%), and impossible in 2 cases (13%). The catheter functioned correctly in 7 patients but problems developed in 6 patients (2 cases of a poor-quality pressure curve, 1 case of a discrepancy of more than 20% in comparison with blood pressure, and 3 cases of impossibility of extracting blood samples through the arterial catheter because the patients were in a lateral decubitus position). No complications relating to arterial puncture were observed. Hemodynamic monitoring showed increased cardiac output after surgery. CONCLUSIONS: The results suggest that using the PiCCO system during lung resection surgery is of limited utility, given that problems developed in relation to 53% of the catheters. This makes the technique unreliable in the event of its being required.

Femoral and sciatic nerve block for knee arthroscopy in a patient with acute intermittent porphyria.

Acute intermittent porphyria is an autosomal dominant disorder that results from a partial deficiency of porphobilinogen deaminase and that causes very severe symptoms. Attacks may be triggered by a series of drugs and by other factors that the anesthesiologist should be aware of in order to reduce morbidity and mortality. Our objective is to review anesthetic considerations in acute intermittent porphyria. We present the case of a patient diagnosed with acute intermittent porphyria who was scheduled for knee arthroscopy. The anesthetic technique used was a femoral and sciatic nerve block under sedation with an infusion of remifentanil. The surgery proceeded without incident and the patient was discharged home after 24h. We consider the use of a peripheral plexus block of the lower limb to have been the safest anesthetic technique for this patient.

[Obstetric analgesia in 28 women with idiopathic thrombocytopenic purpura]. / Analgesia obstétrica en 28 partos de gestantes con purpura trombocitopénica idiopáitica.

OBJECTIVE: To assess complications arising from regional analgesia for obstetric labor and delivery in women with idiopathic thrombocytopenic purpura (ITP). MATERIAL AND METHODS: Retrospective study of case records of women with ITP who gave birth at our hospital over the 10-year period from 1993 through 2002. Quality control checklists were applied to case records before including them for study. The chart had to contain information on the type of analgesia/anesthesia used during labor or cesarean section, the results of complete peripartum coagulation tests, and a record of the presence or absence of anesthetic complications. Twenty-eight births involving 24 patients with ITP were studied. RESULTS: Regional analgesia/anesthesia, usually by epidural infusion, was the technique most often used. All patients had prothrombin and cephalin times within the normal ranges. Regional analgesia/anesthesia was never used in cases where the platelet count was less than 70,000/mm3. In such cases, general anesthesia was used for cesareans, with endovenous administration of opioids. No analgesia was used when the patient declined it for normal deliveries. Eleven cesarean deliveries and 17 vaginal deliveries were recorded. No complications were observed either with regional or endovenous techniques. CONCLUSIONS: The regional neuroaxial techniques used in this series of women with ITP, in whom platelet counts exceeded 70,000/mm3, were not associated with hemorrhagic complications.

Changes in bilateral bispectral index VISTA monitoring system during Wada test.

The Wada test is a procedure used in the preoperative assessment before epilepsy surgery in order to determine language lateralization, to assess the post-operative risk of an amnesia syndrome, and to evaluate the risk of material-specific memory deficits, in particular verbal memory deficits. This test involves inserting a cannula into the internal carotid artery via the femoral artery, and then to inject amobarbital to shut down brain function, usually in one of the brain hemispheres. The bilateral bispectral index (BIS) VISTA™ monitoring system (BVMS) was used to detect changes in EEG, and in the power spectrum distribution using the density spectral array (DSA) of both hemispheres. We describe a patient with an agenesis of the A1 segment of the right anterior cerebral artery, scheduled for a Wada test, in whom the BVMS demonstrated its potential value.

[Extreme leucocytosis can lead to an erroneous diagnosis of severe hypoxaemia. Description of a case]. / La leucocitosis extrema puede inducir a un diagnóstico erróneo de hipoxemia severa. Descripción de un caso.

The diagnosis and treatment of respiratory failure is a part of the anaesthesist's daily practice, as well as the hypoxaemia that is one of its physiological and analytical consequences. Patients with an extreme leucocytosis secondary to leukaemia can suffer an incorrect diagnosis of hypoxemia, called "pseudohypoxaemia". This is basically due to the rapid in vitro oxygen consumption, and is characterized by a low partial pressure of oxygen in arterial blood (PaO2) despite a normal oxygen saturation (SpO2) measured by pulse oximetry. Pseudohypoxaemia appears in patients with thrombocytosis or hyper-leucocytosis occurring during blastic crisis of a leukaemia. It must be suspected in patients with a discrepancy between the SpO2 measured by oximetry and the PaO2. In this context, pulse oximetry is the most accurate way to establish the diagnosis and to avoid unnecessary actions. We report the case of a patient with chronic myeloid leukaemia and extreme leucocytosis requiring emergency surgery, and diagnosed with pseudohypoxaemia during the perioperative period that led to a delay in the extubation of the patient.

[Regional cerebral blood flow monitoring using thermal diffusion flowmetry. Description of 3 cases]. / Monitorización del flujo sanguíneo regional cerebral mediante la flujometría por difusión termal. Descripción de 3 casos.

Cerebral blood flow is the most important physiologic parameter in the setting of brain injury. A regional measurement of the flow (rCBF), can be obtained using continuous methods such as thermal diffusion flowmetry (TD-rCBF). This technology of monitoring allows us to detect and quantify ischemic events related with the temporary artery clipping or malposition of the definitive clip and in patients who have suffered a subarachnoid hemorrhage (SAH) or a traumatic brain injury. Likewise, the precocious detection of ischemic events might help us to adopt more rapidly therapeutic measures and more efficienty. Three cases show during aneurysm clipping procedures and at intensive care: the effects of different hypnotics on TD-rCBF values; the relationship between TD-rCBF and somatosensory and motor evoked potentials; and changes in TD-rCBF and transcranial Doppler ultrasonography (TDU) during a vasospasm. TD-rCBF showed in real-time flow variations induced by anaesthetics and detected changes of CBF earlier than evoked potentials and TDU.