Intrathecal morphine reduces postoperative tramadol consumption in patients undergoing radical retropubic prostatectomy: a randomized trial.

BACKGROUND: Intrathecal (IT) morphine provides prolonged analgesia after major surgery. AIM: The aim of our study was to assess the impact of intrathecal morphine 200 µg on patient-controlled analgesia (PCA) tramadol consumptions and postoperative pain in patients who underwent radical retropubic prostatectomy (RRP) under general anesthesia. MATERIALS AND METHODS: In this prospective trial, 56 men who underwent radical retropubic prostatectomy (RRP) were randomized into 2 groups. Group M received intrathecal morphine (200 µg) before the induction of general anesthesia. Group C did not receive intrathecal morphine. Postoperative analgesia was provided with tramadol PCA. Pain scores, tramadol consumption, adverse effects, rescue analgesia were recorded. RESULTS: Total tramadol consumption at 24 hours and pain scores during 12 hours postoperatively were significantly lower in Group M compared with Group C (p < 0.05). Rescue analgesia and postoperative nausea were lower in Group M than in Group C (p < 0.05). CONCLUSIONS: Intrathecal morphine 200 µg provided a significant reduction in tramadol consumption, postoperative pain scores, rescue analgesia, and postoperative nausea after RRP without serious adverse effects.

Optimization of parameters in coherent spin dynamics of radical pairs in quantum biology.

Identification of the external electromagnetic fields and internal hyperfine parameters which optimize the quantum singlet-triplet yield of simplified radical pairs modeled by Schrödinger system with spin Hamiltonians given by the sum of Zeeman interaction and hyperfine coupling interaction terms are analyzed. A method that combines sensitivity analysis with Tikhonov regularization is implemented. Numerical results demonstrate that the quantum singlet-triplet yield of the radical pair system can be significantly reduced if optimization is pursued simultaneously for both external magnetic fields and internal hyperfine parameters. The results may contribute towards understanding the structure-function relationship of a putative magnetoreceptor to manipulate and enhance quantum coherences at room temperature and leveraging biofidelic function to inspire novel quantum devices.

Cancer detection through Electrical Impedance Tomography and optimal control theory: theoretical and computational analysis.

The Inverse Electrical Impedance Tomography (EIT) problem on recovering electrical conductivity tensor and potential in the body based on the measurement of the boundary voltages on the $ m $ electrodes for a given electrode current is analyzed. A PDE constrained optimal control framework in Besov space is developed, where the electrical conductivity tensor and boundary voltages are control parameters, and the cost functional is the norm difference of the boundary electrode current from the given current pattern and boundary electrode voltages from the measurements. The novelty of the control-theoretic model is its adaptation to the clinical situation when additional "voltage-to-current" measurements can increase the size of the input data from $ m $ up to $ m! $ while keeping the size of the unknown parameters fixed. The existence of the optimal control and Fréchet differentiability in the Besov space along with optimality condition is proved. Numerical analysis of the simulated model example in the 2D case demonstrates that by increasing the number of input boundary electrode currents from $ m $ to $ m^2 $ through additional "voltage-to-current" measurements the resolution of the electrical conductivity of the body identified via gradient method in Besov space framework is significantly improved.

First principles investigations of the structural, elastic, vibrational, and thermodynamic properties of TiMg2O4 oxide spinels: cubic and tetragonal phases.

In the present study ab initio methology under density functional theory with generalized gradient approximation is used to study the structural, elastic, and vibrational properties of TiMg2O4 with cubic and tetragonal phases with space groups (Fd[Formula: see text]m) and P4_122, respectively. The present study shows that the studied compound TiMg2O4 is mechanically stable in both phases. Both phases have ductile nature and strong anisotropic properties, and it is also observed that the tetragonal phase has more anisotropic properties compared to the cubic phase. Obtained structural parameters are in good agreement with related literature.

Identification of parameters in systems biology.

We consider the inverse problem for the identification of the finite dimensional set of parameters for systems of nonlinear ordinary differential equations (ODEs) arising in systems biology. A numerical method which combines Bellman's quasilinearization with sensitivity analysis and Tikhonov's regularization is implemented. We apply the method to various biological models such as the classical Lotka-Volterra system, bistable switch model in genetic regulatory networks, gene regulation and repressilator models from synthetic biology. The numerical results and application to real data demonstrate the quadratic convergence.

Patient-controlled sedation and analgesia during SWL.

Sixty unpremedicated outpatients undergoing elective extracorporeal shockwave lithotripsy (SWL) using a Dornier MPL 9000 lithotripter were randomly assigned to receive either propofol-alfentanil (PA group; N = 30) or midazolam-alfentanil (MA group; N = 30) by a patient-controlled analgesia (PCA) device for sedation and analgesia. Although pain intensity scores were lower after 20 minutes and sedation was more pronounced in the MA group, both drug regimens produced satisfactory sedation and analgesia and allowed the maximum number of shockwaves to be given. Alfentanil consumption was less in the MA group (P < 0.05). Both groups were hemodynamically stable. The patients in the MA group had slower ventilation rates, lower oxygen saturation, and higher end-tidal carbon dioxide levels. Use of MA was associated with more episodes of oxygen desaturation to < 90% (30% vs. 11%; P < 0.05). One patient in the PA group and three patients in the MA group developed bradypnea (< 10 breaths/min). Patient satisfaction was very high with the two sedative-analgesic techniques. Propofol and midazolam, when given in combination with alfentanil using a PCA pump, may provide safe, effective analgesia and sedation during lithotripsy. Patient-controlled sedation and analgesia may provide optimal conditions for SWL of urinary tract stones and is a useful alternative to other forms of anesthesia and analgesia.

Giant cholesteatoma of the external auditory canal.

Cholesteatomas are found almost exclusively in the middle ear and mastoid. Occasionally this disease is seen in the external auditory canal. Cholesteatoma of the external auditory canal is a rare condition. Severe pain and profuse discharge associated with a normal eardrum and normal hearing are essential clinical features. In addition, we found facial paresis and conductive hearing loss in our case. Smaller cholesteatomas can be managed by frequent debridement in the office; larger lesions require surgical intervention. Surgery is successful in resolving otorrhea and relieving pain. In addition, our own experience has shown that surgery is successful in relieving facial paresis.

Effects of preoperative gabapentin on postoperative pain after radical retropubic prostatectomy.

OBJECTIVE: The impact of preoperative gabapentin on tramadol consumption using patient-controlled analgesia (PCA) and postoperative pain was assessed in patients undergoing radical retropubic prostatectomy (RRP). METHODS: In this prospective, randomized trial, 51 patients undergoing RRP were randomized into two groups: the gabapentin group received 900 mg gabapentin orally 2 h before surgery; the control group did not receive gabapentin. Postoperative analgesia was provided by tramadol PCA. Pain was assessed using a visual analogue scale for 24 h, postoperatively. RESULTS: Mean cumulative tramadol consumption at 24 h was comparable in the two groups. Pain scores at 45 min, 60 min and 2 h postoperatively, and the number of patients who required rescue analgesia, were significantly lower in the gabapentin group than in the control group. Side-effects were similar in the two groups. CONCLUSIONS: Preoperative administration of 900 mg gabapentin did not decrease tramadol consumption, but was associated with lower pain scores in the early postoperative phase and a reduced need for rescue analgesia, compared with controls, in patients undergoing RRP.

Complete spontaneous regression of a total pneumothorax in a patient with chronic obstructive lung disease.

A 61-year old man presented with a sudden onset of breathlessness. The total left pneumothorax was overlooked on the initial chest radiograph. One month later, the patient had a partial pneumothorax less than 20% on the radiograph, although he did not receive any therapy against pneumothorax, such as oxygen inhalation or needle aspiration. After the observation for one month, the lungs totally expanded. Pulmonary function tests demonstrated severe chronic obstructive pulmonary disease. To our knowledge, this is the first case in which the total secondary pneumothorax showed a spontaneous remission.

Remifentanil versus alfentanil in total intravenous anaesthesia for day case surgery.

BACKGROUND AND OBJECTIVE: We assessed the intraoperative haemodynamic responses and recovery profiles of total intravenous anaesthesia with remifentanil and alfentanil for outpatient surgery. METHODS: Patients in Group 1 (n = 20) received alfentanil 20 microg kg(-1) followed by 2 microg kg(-1) min(-1) intravenously; patients in Group 2 (n = 20) received remifentanil 1 microg kg(-1) followed by 0.5 microg kg(-1) min(-1) intravenously. Both groups then received propofol 2 mg kg(-1) followed by 9 mg kg(-1) h(-1) intravenously. Five minutes after skin incision, infusion rates were decreased, and at the end of surgery, all infusions were discontinued. Early recovery was assessed by the Aldrete score, whereas intermediate recovery was assessed with the postanaesthetic discharge scoring system (PADS). RESULTS: Perioperative arterial pressure was similar in both groups; heart rate was lower in Group 2 (P < 0.05). The times to spontaneous and adequate respiration, response to verbal commands, extubation and times for Aldrete score > or = 9 were shorter in Group 2 patients (P < 0.05). Pain scores were higher in Group 2 patients (P < 0.05). Overall times for postanaesthetic discharge scores > or = 9 were similar. CONCLUSIONS: Early recovery of patients after day surgery is significantly shorter after total intravenous anaesthesia with remifentanil compared with that with alfentanil but postoperative pain management must be planned ahead.

Resistance to vecuronium in burned children.

We compared the time-course of action of vecuronium in 16 burned children undergoing excision and autograft surgery with that of ten unburned children. Standardized anaesthesia was induced with thiopentone 4-6 mg kg-1 and fentanyl 1 microgram.kg-1 and maintained with endtidal 1-1.5% isoflurane in N2O/O2. Neuromuscular responses were monitored by acceleromyography (TOF-Guard, Organon Teknika/Biometer) with supramaximal train-of-four (TOF) stimuli delivered every 15s. Vecuronium 0.1 mg kg-1 was administered intravenously. Onset was recorded as the time, in seconds, between the initial bolus of vecuronium and a decline in the first twitch of TOF (T1) to 5% of control. The times for the recovery of T1-25%, 50% and 75% of control, recovery index and the recovery of TOF 25% and 50% were recorded. Onset of action was found slower in burned patients (189 +/- 70 s) than in control (98 +/- 20 s) (P < 0.01). Recovery times of T1(25), T1(50), T1(75), TOF25 and TOF50 were significantly shorter in burned patients indicative of decreased sensitivity to vecuronium (P < 0.01).

Tracheal intubation without muscle relaxants: remifentanil or alfentanil in combination with propofol.

BACKGROUND AND OBJECTIVE: In some situations, the use of muscle relaxants (neuromuscular blocking drugs) are undesirable or contraindicated. We compared intubating conditions without muscle relaxants in premedicated patients receiving either alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) followed by propofol 2 mg kg(-1). METHODS: In a randomized, double-blind study, 80 healthy patients were assigned to one of four groups (n = 20). After intravenous atropine, alfentanil 40 microg kg(-1) or remifentanil 2, 3 or 4 microg kg(-1) were injected over 90 s followed by propofol 2 mg kg(-1). Ninety seconds after administration of the propofol, laryngoscopy and tracheal intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of lung ventilation, jaw relaxation, laryngoscopy, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff. RESULTS: Seven patients who received remifentanil 2 microg kg(-1) and one patient who received remifentanil 3 microg kg(-1) could not be intubated at the first attempts. Excellent intubating conditions (jaw relaxed, vocal cords open and no movement in response to tracheal intubation and cuff inflation) were observed in those who received either alfentanil 40 microg kg(-1) (45% of patients) or remifentanil in doses of 2 microg kg(-1) (20%), 3 microg kg(-1) (75%) or 4 microg kg(-1) (95%). Overall, intubating conditions were significantly better (P < 0.05), and the number of patients showing excellent conditions were significantly higher (P < 0.05) in patients who received remifentanil 4 microg kg(-1) compared with those who received alfentanil 40 microg kg(-1) or remifentanil 2 microg kg(-1). No patient needed treatment for hypotension or bradycardia. CONCLUSIONS: Remifentanil 4 microg kg(-1) and propofol 2 mg kg(-1) administered in sequence intravenously provided good or excellent conditions for tracheal intubation in all patients without the use of muscle relaxants.

General anaesthesia or spinal anaesthesia for outpatient urological surgery.

BACKGROUND AND OBJECTIVE: A variety of drugs and techniques have been introduced into ambulatory anaesthesia. The technique as well as the drugs used may hasten or delay home discharge. We compared recovery profiles and side-effects of spinal anaesthesia and total intravenous anaesthesia. METHODS: Forty unpremedicated ASA I-II patients (18-65 yr) undergoing varicocele repair were randomly divided into two groups. Spinal anaesthesia (26-G atraumatic needle) with hyperbaric bupivacaine 0.5% 5 mg and fentanyl 25 microg were given to patients in Group Spinal (n = 20). Patients in Group TIVA (n = 20) received total intravenous anaesthesia with propofol and remifentanil given by continuous infusion; a laryngeal mask was used to secure the airway. The duration of surgery, time to home readiness and side-effects were recorded. RESULTS: The two groups were comparable with respect to patients' characteristics and duration of surgery. The times to achieve ambulation were similar between groups (Spinal = 78.4 +/- 40.9 min, TIVA = 75.9 +/- 13.8 min). Urinary voiding was a requirement for discharge after spinal anaesthesia and the time for home readiness was longer in Group Spinal (158.0 +/- 40.2 versus 94.9 +/- 18.8 min) (P < 0.05). Two patients reported pruritus and one reported postdural puncture headache in Group Spinal, whereas two patients reported nausea in Group TIVA. Patients in Group TIVA had a greater need for analgesia postoperation (P < 0.05). CONCLUSIONS: In healthy unpremedicated men undergoing minor urological operations, total intravenous anaesthesia with remifentanil and propofol provided as safe and effective anaesthesia as spinal block with the advantage of earlier home readiness.