Optofluidic magnetometer developed in a microstructured optical fiber.

A directional, in-fiber optofluidic magnetometer based on a microstructured optical fiber (MOF) Bragg-grating infiltrated with a ferrofluidic defect is presented. Upon application of a magnetic field, the ferrofluidic defect moves along the length of the MOF Bragg grating, modifying its reflection spectrum. The magnetometer is capable of measuring magnetic fields from 317 to 2500 G. The operational principle of such in-fiber magnetic field probe allows the elaboration of directional measurements of the magnetic field flux.

A spectrally tunable microstructured optical fibre Bragg grating utilizing an infiltrated ferrofluid.

The spectral response of a Bragg grating reflector inscribed in a microstructured optical fibre is tuned by employing an infiltrated ferrofluid, while modifying the overlap of the ferrofluidic medium with the grating length. Significant spectral changes in terms of Bragg grating wavelength shift and extinction ratio were obtained under static magnetic field actuation. Spectral measurements revealed non-bidirectional propagation effects dependent upon the relative position between the ferrofluid and the grating. The actuation speed of the device was measured to be of the order of few seconds.

Rotation of antimicrobial therapy in the intensive care unit: impact on incidence of ventilator-associated pneumonia caused by antibiotic-resistant Gram-negative bacteria.

The development of antibiotic resistance is associated with high morbidity and mortality, particularly in the intensive care unit (ICU) setting. We evaluated the effect of an antibiotic rotation programme on the incidence of ventilator-associated pneumonia (VAP) caused by antibiotic-resistant Gram-negative bacteria. We conducted a 2-year before-and-after study at two medical-surgical ICUs at two different tertiary referral hospitals. We included all mechanically ventilated patients admitted for > or =48 h who developed VAP. From 1 January through 31 December 2007, a quarterly rotation of antibiotics (piperacillin/tazobactam, fluoroquinolones, carbapenems and cefepime/ceftazidime) for the empirical treatment of VAP was implemented. We analysed the incidence of VAP and the antibiotic resistance patterns of the responsible pathogens in 2006, before (P1) and, in 2007, after (P2) the introduction of the scheduled rotation programme. Overall, there were 79 VAP episodes in P1 and 44 in P2; the mean incidence of VAP was 20.96 cases per 1,000 days of mechanical ventilation (MV) during P1 and 14.97 in P2, with no significant difference between periods on segmented regression analysis. We observed a non-significant reduction of the number of both the poly-microbial (14 [17.7%] in P1 and 5 [10.6%] in P2 [p = 0.32]) and of the antibiotic-resistant Gram-negative bacteria-related VAP (42 [45.2%] in P1 and 16 [34%] in P2 [p = 0.21]). Conversely, the number of VAP caused by Pseudomonas aeruginosa passed from 8.35 per 1,000 days of MV in P1 to 2.33 per 1,000 days of MV in P2 (p = 0.02). No difference in ICU mortality and crude in-hospital mortality between P1 and P2 was noted. Moreover, no significant change of microbial flora isolated through clinical cultures was observed. We were able to conclude that, despite global microbial flora not being affected by such a programme, antibiotic therapy rotation may reduce the incidence of VAP caused by antibiotic-resistant Gram-negative bacteria in the ICU, such as Pseudomonas aeruginosa. The application of this programme may also improve antibiotic susceptibility. However, further studies are needed to confirm our results.

The early phase of critical illness is a progressive acidic state due to unmeasured anions.

BACKGROUND AND OBJECTIVE: Stewart's and Fencl's methods have recently been proposed to interpret acid-base disorders where traditional theory has proven inadequate. Our objectives were to evaluate: (1) the occurrence of acid-base disturbances in critically ill patients and their trend over the first 3 intensive care unit days, (2) whether Stewart's theory offers advantages over the traditional theory in the diagnosis of acid-base metabolic disturbances and (3) whether variables derived from Stewart's and Fencl's methods offer advantages over the traditional method to predict patient mortality. METHODS: A prospective cohort study in a general intensive care unit. Blood samples were analysed for arterial blood gases, electrolytes and proteins. PaCO2, pH, bicarbonate, base excess, standard base-excess, sodium, potassium, chloride, phosphorous, calcium, magnesium and lactate were measured. Anion gap, Stewart's and Fencl's variables were calculated. RESULTS: When using Stewart's method, metabolic acidosis and metabolic alkalosis were found in 92.9% and 93.4% of samples, respectively. Corresponding figures obtained with the traditional method were 15% and 18.7%. In 245 (64.5%) samples, Stewart's method revealed that metabolic acidosis and alkalosis were simultaneously present, whereas the traditional method revealed a normal acid-base status. Strong ion gap increased significantly over the first 3 intensive care unit days. Strong ion gap and lactate were independent predictors of 28-day mortality. CONCLUSIONS: Metabolic acidosis by unmeasured anions is a clinically relevant phenomenon, which is correlated with mortality. Progressive metabolic acidosis may be ongoing in the early phase of critical illness despite the absence of acidaemia.

Antibiotic prophylaxis of early onset pneumonia in critically ill comatose patients. A randomized study.

OBJECTIVE: To evaluate if a 3-day ampicillin-sulbactam prophylaxis can reduce the occurrence of early-onset pneumonia (EOP) in comatose mechanically-ventilated patients. DESIGN: This was a single-centre, prospective, randomised, open study. SETTING: A 10-bed general-neurological ICU in a 2,000-bed university hospital. PATIENTS AND PARTICIPANTS: Comatose mechanically-ventilated patients with traumatic, surgical or medical brain injury. INTERVENTIONS: Patients were randomized to either ampicillin-sulbactam prophylaxis (3 g every 6 h for 3 days) plus standard treatment or standard treatment alone. MEASUREMENTS AND RESULTS: Main outcome was the occurrence of EOP. Secondary outcome measures were occurrence of late-onset pneumonia, percentage of non-pulmonary infections and of emerging multiresistant bacteria, duration of mechanical ventilation and of ICU stay and ICU mortality. Interim analysis at 1 year demonstrated a statistically significant reduction of EOP in the ampicillin-sulbactam group, and the study was interrupted. Overall, 39.5% of the patients developed EOP, 57.9% in the standard treatment group and 21.0% in the ampicillin-sulbactam group (chi-square 5.3971; P =0.022). Relative risk reduction of EOP in patients receiving ampicillin-sulbactam prophylaxis was 64%; the number of patients to be treated to avoid one episode of EOP was three. No differences in other outcome parameters were found; however, the small sample size precluded a definite analysis. CONCLUSIONS: Antibiotic prophylaxis with ampicillin-sulbactam significantly reduced the occurrence of EOP in critically ill comatose mechanically ventilated patients. This result should encourage a large multicenter trial to demonstrate whether ampicillin-sulbactam prophylaxis reduces patient mortality, and whether antibiotic resistance is increased in patients receiving prophylaxis.

Negative pressure ventilation vs external high-frequency oscillation during rigid bronchoscopy. A controlled randomized trial.

STUDY OBJECTIVES: To compare the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO). DESIGN: Prospective, controlled, randomized, nonblinded study. SETTING: University-affiliated hospital. PATIENTS: Seventy patients undergoing interventional rigid bronchoscopy for tracheobronchial lesions were enrolled into the study. INTERVENTIONS: Mechanical ventilation was performed by INPV or EHFO. When pulse oximetry was < 90%, manually assisted ventilation was delivered. MEASUREMENTS AND RESULTS: Arterial blood gases were sampled preoperatively and intraoperatively. Most patients in both groups had normal intraoperative PaCO(2) (mean, 43. 6 +/- 11.8 mm Hg under EHFO and 37.4 +/- 8.2 mm Hg under INPV; p = 0.012), and acidemia occurred in 9 of 35 patients of EHFO group and in 2 of 35 patients of INPV group (p = 0.049). Hypercapnia (PaCO(2) > 50 mm Hg) was observed in 10 patients under EHFO and in 2 with INPV (p = 0.026). Intraoperative mean PaO(2) was similar (101.4 +/- 52.9 mm Hg with EHFO and 124.2 +/- 50.3 mm Hg with INPV; p = 0.07), but O(2) supply was different (3.5 +/- 2.3 L/min during INPV and 8.5 +/- 6.2 L/min during EHFO; p < 0.001). Intraoperative hypoxemia (PaO(2) < 60 mm Hg) occurred in five patients with EHFO and two with INPV (p = 0.426). Three EHFO patients required manually assisted ventilation (mean, 0.2 +/- 0.9), but no INPV patient did (p = 0.142). CONCLUSIONS: External negative pressure ventilation appears to be a suitable choice during rigid bronchoscopy: both EHFO and INPV ensure effective ventilation and comfortable operating conditions in the majority of patients. Some patients may receive inadequate ventilation with EHFO, developing respiratory acidosis and requiring manually assisted ventilation. In comparison with INPV, EHFO requires a higher fraction of inspired oxygen.

Breathing pattern and arterial blood gases during Nd-YAG laser photoresection of endobronchial lesions under general anesthesia: use of negative pressure ventilation: a preliminary study.

STUDY OBJECTIVE: To evaluate the efficacy of negative pressure ventilation (NPV) in avoiding or reducing apneas and related hypoxemia and respiratory acidosis during laser therapy (LT) of endobronchial lesions. DESIGN: A prospective, controlled, randomized study. SETTING: An operating theater of a respiratory endoscopy and laser therapy unit. POPULATION AND INTERVENTION: Twenty-seven consecutive patients referred to LT were entered into the study. Fourteen patients were randomly assigned to LT under general anesthesia and spontaneous assisted ventilation (control group) whereas in 13 cases, NPV by a poncho-wrap ventilator (NPV group) was added to the procedure. MEASUREMENTS AND RESULTS: The prevalence and the duration of apnea/hypopnea periods assessed by respiratory inductive plethysmography during LT were significantly reduced under NPV, compared to the control group. As compared to baseline, during LT, all control patients developed mild to severe hypercapnia (PaCO2 ranging from 55 to 76 mm Hg) and respiratory acidosis (pH from 7.33 to 7.19), whereas only three patients undergoing NPV (23%) developed hypercapnia (PaCO2 from 52 to 68 mm Hg) and related acidosis (pH from 7.29 to 7.21). Optimal oxygenation was achieved in all of the patients; nevertheless, patients under NPV needed a lower mean oxygen supply; five of them (38%) could be treated at a fraction of inspired oxygen of 0.21 for the whole procedure. CONCLUSION: NPV may be useful in reducing apneas during laser therapy under general anesthesia, thus reducing hypercapnia, related acidosis, and need of oxygen supplementation.

Clinical applications of independent lung ventilation with unilateral high-frequency jet ventilation (ILV-UHFJV).

Six patients with unilateral acute lung injury (ALI) were treated with a new form of ventilatory support: independent lung ventilation with unilateral high-frequency jet ventilation (ILV-UHFJV). The first three patients suffered from unilateral ALI complicated by a bronchopleural fistula (BPF); they were at first ventilated with HFJV, but remained unresponsive to treatment, showing a progressive impairment of the ventilation/perfusion ratio with a deterioration in clinical condition. After selective bronchial intubation, ILV-UHFJV was started, ventilating the healthy lung with CPPV and the contralateral with HFJV. ILV-UHFJV caused a significant improvement in alveolar gas exchange leading to a rapid fall in Qs/Qt; it was also associated with a stable haemodynamic condition throughout the duration of the treatment. Subsequently, three more patients were treated; their respiratory failure was due to a unilateral ALI without BPF, unresponsive to either HFJV or CPPV. Once again, ILV-UHFJV was followed by a dramatic improvement in respiratory function; the haemodynamics remained unchanged and it was also possible to demonstrate a rapid improvement in individual and overall lung function.

Bedside burr hole for intracranial pressure monitoring performed by intensive care physicians. A 5-year experience.

OBJECTIVE: To assess the results of a 5-year experience with bedside burr hole for intracranial pressure (ICP) monitoring performed by intensive care physicians. DESIGN: Prospective, observational study in 120 patients. SETTING: A general-neurologic Intensive Care Unit in a University Hospital. PATIENTS: Patients admitted for acute neural lesion requiring ICP monitoring. METHOD: A 2.71 mm burr hole was made with positioning of a subarachnoid screw, through which a miniaturized fiberoptic, tip transducer device (Camino) was advanced and inserted 2 mm in the frontal cortex. MAIN RESULTS: Over a 5-year period 120 patients, mainly with severe head trauma, underwent ICP monitoring. None of the planned patients was excluded because of technical difficulties. No life-threatening complications were reported, and the overall morbidity rate related to the ICP monitor was 3.3%. Complications were infectious in nature, with 2.5% wound infections and 0.8% meningitis. Although seven patients bled when opening the dura, no intracranial hematomas were recorded due to the ICP monitor. The fiberoptic device was left in place for 5 +/- 1.6 (SD) days (range 1-12 days). Five patients (4.1%) required catheter substitution due to breakage of the system components (fiberoptics). CONCLUSIONS: Bedside insertion of a ICP monitor performed by intensive care physicians is a safe procedure, with a complication rate comparable to other series published by neurosurgeons. The overall morbidity rate is comparable to, or even lower than, that caused by central vein catheterization.

Acute neuromuscular respiratory failure after ICU discharge. Report of five patients.

OBJECTIVE: To describe a syndrome of acute neuromuscular respiratory failure (NM-ARF) caused by ICU-acquired acute myopathy and neuropathy. DESIGN: Case series. SETTING: General Regional University Hospital in Brescia, Italy. PATIENTS: Five adult patients with NM-ARF after prolonged ICU stay and successful weaning from the ventilator and ICU discharge. INTERVENTIONS: None. MEASUREMENTS: Clinical signs of NM-ARF, electroneurography and electromyography (ENMG) of peripheral nerves and muscles, and functional assessment of respiratory muscles. RESULTS: NM-ARF was diagnosed at the time of (one case), or 1-3 days after, ICU discharge. Limb weakness alarmed the physicians, while the signs of the NM-ARF were initially undetected. In the first observed case the acute respiratory failure was near fatal, and necessitated ICU readmission, while in the other cases 2 weeks of aggressive chest physiotherapy permitted resolution of the respiratory failure. History, clinical course and ENMG indicated the diagnosis of critical illness myopathy and neuropathy (CRIMYNE). Three patients recovered fully, while two had persisting evidence of axonal polyneuropathy several months after the onset. CONCLUSIONS: Critically ill patients with prolonged ICU stay, sepsis and MOF are at great risk of developing CRIMYNE, which in turn may be responsible for NM-ARF. This latter complication may arise after resolution of the respiratory and cardiac dysfunctions and successful weaning from the ventilator. As NM-ARF may cause unplanned ICU readmission or even unexpected death, strict clinical surveillance and monitoring of respiratory muscle function is recommended after discharge to the general ward of patients with proven NM-ARF. Early intensive chest physiotherapy can resolve the condition.

Clinical use of differential continuous positive airway pressure in the treatment of unilateral acute lung injury.

In some instances of unilateral acute lung injury (ALI) refractory to conventional ventilatory support, the intact lung is still able to ensure an efficient CO2 washout, the concomitant hypoxaemia being due to the loss of volume of the injured parenchyma. In these cases, the administration of a sufficient selective continuous distending pressure by means of differential continuous positive airway pressure may restore to normal the resting volume and thus the ventilatory performance of the affected lung, contemporarily avoiding the occurrence of pulmonary and systemic barotrauma.

Free radical-induced lipoperoxidation and severe head injury. A clinical study.

Ten severely head injured patients (GCS less than or equal to 8), aged 17-62 years, were studied in order to investigate the role of lipoperoxidation in secondary brain damage. No patients had intracranial mass lesions, shock, hypoxemia, fever or sepsis. Blood samples were taken from the jugular bulb and from the right atrium, and thiobarbituric acid reacting substances (TBARS) were measured in plasma by spectrophotometry. Arterio-jugular venous oxygen differences (AVDO2) were obtained in seven patients, in order to estimate cerebral blood flow. Jugular TBARS (TBARSj) were always elevated (from To, to 2 h after injury) and correlated in a linear fashion with TBARS of right atrium (TBARSv): r = 0.74, p less than 0.001. TBARSj and AVDO2 are closely correlated, in accordance with an exponential function (R = 0.45, p less than 0.001) which describes how any cerebral perfusion derangement determines high levels of TBARSj, confirming lipoperoxidation as a key factor in the final common pathway of secondary posttraumatic brain damage.

Increase of intraerythrocytic fructose-1,6-diphosphate after incubation of whole human blood with fructose-1,6-diphosphate.

The incubation of whole blood with fructose-1,6-diphosphate (FDP) entails a statistically significant increase of intraerythrocytic FDP together with a decrease of blood glucose. The increase is not significant when equimolar amounts of fructose plus twice molar phosphate are used. The effect of FDP is decreased in the presence of an excess of oxygen. FDP added to the whole blood is removed from plasma by the activity of plasma enzymes and by the presence of blood cells as well. No specific interaction of FDP with plasma proteins seems to occur and the effects of FDP addition last longer than is compatible with the presence of FDP in the plasma.

Limits of intermittent jugular bulb oxygen saturation monitoring in the management of severe head trauma patients.

OBJECTIVE: To evaluate, in a prospective, observational study, whether bilateral monitoring of jugular bulb oxyhemoglobin saturation (SjO2), in addition to standard monitoring, results in modification of the management of severe head trauma. METHODS: The patients underwent bilateral jugular bulb cannulation and observation at 8-hour intervals, during which SjO2 was measured and the neurological condition and physiological variables were assessed. The study group was responsible for evaluating whether the physician's decision-making process was influenced by the detection of SjO2 abnormalities. The SjO2 discrepancy in simultaneous bilateral samples was also evaluated to determine whether it interfered with the interpretation of data and with clinical decision-making. The SjO2-related complications were monitored. RESULTS: Thirty patients underwent 319 observations. In 96% of patients, SjO2 was normal or high and had no influence on the diagnostic or therapeutic strategies. Treatment decisions were dictated by changes in clinical status and in intracranial and cerebral perfusion pressure. When these parameters were abnormal, treatment was administered, even if SjO2 was normal (101 observations). Conversely, when SjO2 was the only detected abnormality (34 observations), no treatment was administered. Abnormally low SjO2 values, caused by hypovolemia and hypocapnia, were detected in 3.4% of observations and actually modified the management. The discrepancies in simultaneous bilateral samples were substantial and gave rise to relevant interpretation problems. Fifteen percent of jugular catheters showed evidence of bacterial colonization. CONCLUSION: Intermittent SjO2 monitoring did not substantially influence the management of severe head trauma. Therefore, recommendation for its routine use in all patients seems inadvisable, and indications for this invasive method should no longer be defined on the basis of experts' opinions, but rather on randomized, prospective studies.

Acute quadriplegia with delayed onset and rapid recovery. Case report.

The authors describe a patient with severe head injury and sepsis who became acutely quadriplegic 3 days postinjury because of a critical illness polyneuropathy (CIP) and critical illness myopathy (CIM), which resolved rapidly after treatment of the underlying infection. In only 3 days the patient developed septic shock together with flaccid quadriplegia and absent deep tendon reflexes with no clinical or radiological evidence of central nervous system deterioration. Neurophysiological studies showed an acute axonal sensorimotor polyneuropathy, whereas the clinical course strongly suggested a concurrent myopathy. A severe Staphylococcus epidermidis infection accompanied by bacteremia was treated and the patient recovered fully within a few days. Although the case described here is unique because of its very early onset and rapid resolution, CIP and CIM are frequent complications of sepsis and multiple organ failure. The authors suggest that severely head injured patients with sepsis should be evaluated for CIP and CIM when presenting with unexplained muscle weakness or paralysis.

Effects of L-carnitine administration on mitochondrial electron transport activity present in human muscle during circulatory shock.

Carnitine was administered to a group of patients in shock, and the activities of cytochrome oxidase and succinate cytochrome c reductase in muscle needle biopsies from these patients were compared to those activities present in a non-carnitine treated control group of patients. Carnitine seemingly exerted a significant protective action on cytochrome oxidase activity during the initial phases of shock, but not to such an extent on succinate cytochrome c reductase activities.

[Primary lymphoma of the kidney. Description of a case and brief review of the literature]. / Il linfoma primitivo del rene. Descrizione di un caso e breve revisione della letteratura.

Stage IV disseminated non-Hodgkin lymphomas show kidney involvement with frequency; on the contrary, primary kidney lymphoma, as the sole presenting feature, is a very rare disease. Non-Hodgkin histological pattern, atypical symptoms, marked discrepancy between parenchymal involvement and impairment of renal function are the main features of this tumor. A case-report of a primary kidney non-Hodgkin lymphoma will be described; a short review of literature on this subject will be discussed.

Impact of heat and moisture exchangers on ventilatory pattern and respiratory mechanics in spontaneously breathing patients.

The upper airways warm and saturate inspired air with water vapour. In intubated or tracheotomized patients, this function is replaced either by hot water humidifiers or by heat and moisture exchangers (HMEs). The aim of this study was to quantify the modifications of ventilatory mechanics and patients' work when two different HMEs were added to spontaneously breathing patients. We studied nine consecutive patients with no previous history of chronic obstructive lung disease. All patients had been weaned from mechanical ventilation. They were breathing through devices supplying positive end-expiratory pressure and/or O2 enrichment. Two different HMEs were used: Icor Mediflux 1 and Icor Mediflux 2. These HMEs have identical chemical composition and configuration, but the Mediflux 1 is larger than the Mediflux 2. The humidification of the inspired gases was obtained alternatively by an active humidifier and the two HMEs. Data regarding ventilatory pattern and respiratory mechanics were collected by pulmonary monitor CP100 (Bicore). Tidal volume, work of breathing and pressure-time product were greater with Mediflux 1 than with Mediflux 2 or active humidifier. There were no significant differences in respiratory rate, intrinsic positive end-expiratory pressure (PEEPi), rapid shallow breathing index, arterial CO2 and O2 partial pressure. The larger HME (Mediflux 1) increased patient's effort, with no evidence of patient discomfort. However, the smaller HME (Mediflux 2) did not add a detectable load and provided adequate humidification. In conclusion, the smaller HME appears to be preferable for the management of spontaneously breathing patients.

[Lymphoma of the prostate: case reports and subject review]. / Il linfoma della prostata: contributo clinico e revisione dell'argomento.

Malignant lymphomas involving the prostate are rare whether as primary lymphoma or as secondary to generalized disease. Middle age, histotype prevalently non Hodgkin, intermediate and high grade of malignancy, symptoms of bladder outflow obstruction, diagnosis generally made after histological examination, severe prognosis are the most important features that result from literature review. The evaluation of therapeutic treatments is difficult as most reports do not include a sufficient number of cases. The Authors presenting two cases of lymphoma of the prostate point out the usefulness of radiotherapy since the prostate is usually a bulky seat of disease and suggest the combination with multiple drug chemotherapy for intermediate and high grade of malignancy and in advanced stages. The authors suggest that prognosis depends on histotype rather than on prostatic involvement of disease.

Buprenorphine versus tramadol as perineural adjuvants for postoperative analgesia in patients undergoing arthroscopic rotator cuff repair under middle interscalene block: a retrospective study.

BACKGROUND: The aim of this retrospective study was to compare buprenorphine and tramadol, in order to assess their different efficacy in prolonging postoperative analgesia and their associated side effects when used as perineural adjuvants with a local anesthetic. METHODS: The clinical records of 161 consecutive ASA 1-2 adult patients scheduled for arthroscopic rotator cuff repair and fulfilling the inclusion/exclusion criteria were reviewed retrospectively. The anaesthesia was performed using the middle interscalene block (MIB). The 161 patients were divided into three groups (A, B, T) according to their utilization of buprenorphine (B), tramadol (T) or neither of the latter (A) as perineural adjuvants: group A (54 patients) - levobupivacaine 0.75%, 0.4 mL/kg; group B (56 patients) - levobupivacaine 0.75%, 0.4 mL/kg + 0.15 mg buprenorphine; group T (51 patients) - levobupivacaine 0.75%, 0.4 mL/kg + 100 mg tramadol. RESULTS: The results showed that the group treated with buprenorphine benefited from a longer post-operative analgesia than that treated with local anesthetic alone (P<0.0001). Otherwise, a less evident not statistically significant (P=0.4825) difference turned out between the group treated with the anesthetic alone and the group treated with tramadol as adjuvant. No difference turned out to be between the local anesthetic alone treatment and the tramadol-local anesthetic one (P=0.4825; HR=0.863, 95% CI 0.574-1.299); on the contrary, a significant difference was demonstrated between the buprenophine-local anesthetic group and the local anesthetic alone one (P<0.0001; HR=0.330, 95% CI 0.216-0.530) CONCLUSION: Both buprenorphine and tramadol are effective as perineural adjuvants used in order to prolong the postoperative analgesia, buprenorphine proving more efficacious for this purpose than tramadol.