Bispectral index-guided intraoperative sedation with dexmedetomidine and midazolam infusion in outpatient cataract surgery.

BACKGROUND: This study aimed to evaluate the role of alfa-2 agonist infusion, with dexmedetomidine or midazolam, on hemodynamic and respiratory parameters while titrating the sedation level with the bispectral index (BIS) during cataract surgery. METHODS: Ninety consenting ASA class I-III patients who were electively undergoing cataract surgery were enrolled in the double blind study. A random infusion of 0.25 microg kg(-1) hr(-1) Dexmedetomidine (Group D), 25 microg kg(-1) hr(-1) midazolam (Group M), or saline for controls (Group C) was administered after mounting a BIS monitor and routine anesthetic care. The target BIS level was >85. An additional bolus dose in 1 mL increments of the study drug or cessation of the infusion was adjusted according to the BIS level. Changes in respiratory and vital parameters were noted and, in case of mild pain, 25 microg fentanyl was administered as a bolus. Pain and sedation were evaluated in the early postoperative period using visual analogue and four rating sedation scales. RESULTS: In Group D, heart rate decreased in the later periods of surgery (35-50 min) and in the early postoperative period (5(th) and 15(th) min). Dose adjustments were required in six and ten patients in Groups D and M, respectively. Pain scores were lower with dexmedetomidine infusion. CONCLUSIONS: Dexmedetomidine infusion mildly decreased heart rate in the later periods of surgery with better pain scores in the postoperative period. Dexmedetomidine should be an alternative for intraoperative sedation in outpatient cataract surgery.

Preliminary report on surgical mask induced deoxygenation during major surgery.

OBJECTIVES: This study was undertaken to evaluate whether the surgeons' oxygen saturation of hemoglobin was affected by the surgical mask or not during major operations. METHODS: Repeated measures, longitudinal and prospective observational study was performed on 53 surgeons using a pulse oximeter pre and postoperatively. RESULTS: Our study revealed a decrease in the oxygen saturation of arterial pulsations (SpO2) and a slight increase in pulse rates compared to preoperative values in all surgeon groups. The decrease was more prominent in the surgeons aged over 35. CONCLUSIONS: Considering our findings, pulse rates of the surgeon's increase and SpO2 decrease after the first hour. This early change in SpO2 may be either due to the facial mask or the operational stress. Since a very small decrease in saturation at this level, reflects a large decrease in PaO2, our findings may have a clinical value for the health workers and the surgeons.

Preliminary report on surgical mask induced deoxygenation during major surgery

Objetivos. Este estudio se realizó para determinar si la saturación de oxígeno del cirujano se afectaba por el uso de la mascarilla, durante intervenciones de larga duración .Métodos. Se hizo un estudio longitudinal y prospectivo en 53 cirujanos con medidas de la hemoglogina realizadas con un oxímetro para medir la saturación del pulso arterial. Se hicieron estudios antes y después de la operación. Resultados. Nuestro estudio puso de manifiesto una disminución de la saturación de oxígeno de las pulsaciones arteriales (SpO2) y un ligero aumento de las pulsaciones en comparación con el estado preoperatorio en todos los grupos de cirujanos. La disminución era mayor en el grupo de edad superior a los 35 años. Conclusiones. Según nuestros hallazgos, el ritmo del pulso aumenta y la concentración de SpO2 disminuye después de la primera hora de la operación. Este cambio temprano de SpO2 puede deberse a la mascarilla o al estrés de la intervención. Puesto que un ligero descenso en la saturación a este nivel refleja una mayor disminución de la PaO2, nuestros datos pueden tener un valor clínico para la salud del personal sanitario y para los cirujanos

Objectives. This study was undertaken to evaluate whether the surgeons' oxygen saturation of hemoglobin was affected by the surgical mask or not during major operations. Methods. Repeated measures, longitudinal and prospective observational study was performed on 53 surgeons using a pulse oximeter pre and postoperatively. Results. Our study revealed a decrease in the oxygen saturation of arterial pulsations (SpO2) and a slight increase in pulse rates compared to preoperative values in all surgeon groups. The decrease was more prominent in the surgeons aged over 35.Conclusions. Considering our findings, pulse rates of the surgeon's increase and SpO2 decrease after the first hour. This early change in SpO2 may be either due to the facial mask or the operational stress. Since a very small decrease in saturation at this level, reflects a large decrease in PaO2, our findings may have a clinical value for the health workers and the surgeons

An intraoperative unexpected respiratory problem in a patient with Apert syndrome.

We present a case of a 5-year-old child who underwent four operations (three for syndactyly of the hands and one for craniofacial corrections). At the third hour of his craniofacial operation, his EtCO2 started to increase and airway resistance was encountered during manual ventilation. The position of the head and neck was checked. An increase in secretion with oral and endotracheal aspiration and a decrease in saturation were observed. When breath sounds disappeared, the patient was reintubated orally. The nasal tube was obstructed with a mucolytic plug. There was no problem during the other operations. This case is presented since anaesthesiologists should be aware of the high incidence of respiratory complications in Apert syndrome.

Postoperative magnesium sulphate infusion reduces analgesic requirements in spinal anaesthesia.

BACKGROUND AND OBJECTIVES: Magnesium sulphate infusion during general anaesthesia reduces anaesthetic consumption and analgesic requirements. The aim of this study was to assess the effects of postoperative magnesium infusion on duration of block, sedation and analgesic consumption after spinal anaesthesia. METHODS: Fifty ASA I-II patients were included in the randomized double blind study. Spinal anaesthesia was performed at L3-4 or L4-5 interspace with 12.5 mg 0.5% heavy bupivacaine, using a 25 G Quincke needle. Patients received a 5 mg kg(-1) bolus of magnesium sulphate followed by a 500 mg h(-1) infusion or saline in the same volumes for 24 h. Time to first pain, analgesic request, return of motor function, visual analogue pain and sedation scores were evaluated every 4 h during the 24 h postoperative period. The t- and U-tests were used for statistical analyses. Data were expressed as mean +/- SD, with P < 0.05 being considered significant. RESULTS: Vital signs were stable during spinal anaesthesia and postoperative period. When compared to the control group, time to analgesic need was increased and total analgesic consumption was reduced in the magnesium group (meperidine consumption 60.0 +/- 73.1 mg control group, 31.8 +/- 30.7 mg magnesium group, P = 0.02). CONCLUSIONS: Magnesium sulphate infusion may be used as an adjunct for reducing analgesic consumption after spinal anaesthesia.

Perioperative intravenous adenosine infusion to extend postoperative analgesia in brachial plexus block.

BACKGROUND AND OBJECTIVE: Adenosine infusions have been shown to reduce requirements of anaesthetics, to decrease the need for postoperative analgesics and to attenuate hyperaesthesia related to neuropathic pain. We decided to investigate the effects, beneficial or otherwise, of an adenosine infusion administered during surgery. A brachial plexus block was used to produce anaesthesia for the surgery. METHODS: Sixty adults undergoing upper extremity surgery were included in the study. Brachial plexus block was performed via an axillary approach with lidocaine 1.25% and epinephrine 1/200 000 (40 mL). Patients were randomly assigned to two groups. During surgery, saline (control) or adenosine 80 microg kg min was infused intravenously in a double-blind fashion for 1 h. Visual analogue scores every 4 h, analgesic consumption, time to first spontaneous pain sensation, time to first rescue analgesic and adverse effects were noted during the first 24 h. RESULTS: Vital signs were stable in both groups throughout surgery. During the adenosine infusion, one patient fainted while another complained of palpitations and tightness of the chest; both patients were excluded from further analyses. The time to first sensation of pain was significantly longer in the adenosine group compared to the control group (438 +/- 387 vs. 290 +/- 227 min, P = 0.02). The time to first rescue analgesic, the visual analogue scale scores and analgesic consumption in the postoperative period were similar. CONCLUSIONS: In patients undergoing surgery with an axillary plexus block, a perioperative adenosine infusion prolongs the duration of postoperative analgesia to some extent. However, the time to first rescue analgesic, total analgesic requirements and pain scores were unchanged; the risk of potentially serious adverse effects is high. This therapy cannot be recommended.

Effect of bispectral index monitoring on sevoflurane consumption.

BACKGROUND AND OBJECTIVE: The bispectral index, a parameter derived from the electroencephalograph, has been shown to correlate with the loss of consciousness and sedation. This study was designed to assess the effects of bispectral index monitoring on sevoflurane and its recovery profiles. METHODS: Sixty ASA I and II patients undergoing open abdominal surgery were randomized into two groups: one monitored using the bispectral index (Group BIS) and the other without its use (controls). After a standardized induction, anaesthesia was maintained with sevoflurane in both groups. In Group BIS, sevoflurane was titrated to maintain the bispectral index in the range 40-60. In the control group, the administered sevoflurane concentration was adjusted according to the signs of anaesthesia. The end-tidal sevoflurane concentration, bispectral index and routine haemodynamic variables were noted every 5 min during surgery. The consumption of sevoflurane was computed. At the conclusion of surgery operations, the time to 'open eyes on verbal command', 'motor response to verbal command' and Aldrete's score were recorded by a blinded anaesthesiologist. RESULTS: The difference in the consumption of sevoflurane was not significant between the groups. Bispectral index monitoring was associated with a reduction of 4.73% in sevoflurane usage and 2.19 mL h(-1) was saved. CONCLUSIONS: Bispectral index monitoring during anaesthesia provides only a small advantage related to the need to monitor the depth of anaesthesia.

A comparison of four intravenous sedation techniques and Bispectral Index monitoring in sinonasal surgery.

This study was performed to investigate the quality of different intravenous sedation techniques, and the correlation between the Bispectral Index (BIS) values and the Observer's Assessment of Alertness/Sedation (OAA/S) scores. Eighty patients undergoing sinonasal surgery were randomly assigned to one of four groups. Group MF received midazolam and fentanyl, group PF received propofol and fentanyl, group MR received midazolam and remifentanil, and group PR received propofol and remifentanil. Heart rate and mean arterial pressure values were not different among the groups. SpO2 decreased only after intravenous medication in groups MF and MR (P < 0.017). Emesis was less common with propofol. A positive relationship existed between the BIS values and OAA/S scores during the operation in all groups and the strongest correlation was observed in group PR (r = 0.565 and P < 0.001). In conclusion, these four intravenous sedation techniques did not change mean arterial pressure, heart rate or SpO2 clinically and produced a similar level of light sedation. The BIS was useful for monitoring of sedation during sinonasal surgery under local anaesthesia with intravenous sedation.

Combination of adenosine with prilocaine and lignocaine for brachial plexus block does not prolong postoperative analgesia.

Adenosine analogues have been used by subarachnoid injection for the treatment of inflammatory and neuropathic pain. There is no data on the use of adenosine in peripheral nerve blocks. The aim of the present study was to determine the analgesic efficacy of adenosine in combination with a local anaesthetic solution for brachial plexus (BP) block. With local ethics committee approval, 50 consenting adult patients undergoing upper limb surgery were enrolled in this double-blind, prospective, randomized study. Patients with a history of bronchospastic disease were excluded. Patients were instructed not to take theophylline-containing drugs and beverages for at least one day before surgery or on the first postoperative day. A supraclavicular BP block was performed by injecting a mixture totalling 35 ml made up of prilocaine 1% 10 ml and lignocaine 2% 20 ml with adrenaline 1:200,000, and adenosine 10 mg in 5 ml saline (Group 1) or 5 ml saline (Group 2) as a placebo control group. Postoperative analgesia was assessed by time to first rescue analgesia, analgesic consumption in the first 24 hours, and VAS at rest at 4, 8, 12, 16, 20 and 24 hours. Side-effects were also noted. Vital signs were stable in both groups throughout the operation. There were no significant differences between the groups in onset of motor and sensory block. Time to first pain sensation from block was not significantly longer in the adenosine group (379 +/- 336 min) compared with controls (304 +/- 249 min, mean +/- SD, P = 0.14). Time to first analgesic requirements and analgesic consumption in the first 24 hours were also similar in both study groups. In the present study, the addition of adenosine to local anaesthetic in brachial plexus block did not significantly extend the duration of analgesia.

Comparison of three analgesics for extracorporeal shock wave lithotripsy.

OBJECTIVE: The aim of the study was to compare the clinical efficacy of three different analgesic drugs with respect to their level of sedation, analgesia and quick mobilisation without cardiopulmonary depression, for outpatient extracorporeal shock wave lithotripsy (ESWL) procedure. MATERIAL AND METHODS: Sixty outpatients undergoing elective ESWL using a third generation lithotriptor were studied. The patients were randomly divided into three groups of twenty patients. All patients received midazolam (2 mg) intravenously five minutes before the procedure. In group F, fentanyl was given (1 microg kg(-1) IV) at the same time with midazolam. In group D, diclofenac sodium was given (1 mg kg(-1), IM) intramuscularly 45 minutes before ESWL. In group T, tramadol was given (1.5 mg kg(-1)) 30 minutes before ESWL. Arterial pressure, heart rate, respiratory rate and oxygen saturation were recorded before the procedure, after sedation, at the first minute, and every ten minutes during the procedure. Pain intensity was identified with a Visual Analogue Scale. The level of sedation was evaluated by using the Observer's Assessment of Alertness/Sedation Scale. All patients were asked to assess their satisfaction with the seven point Verbal Rating Scale before discharge. Side-effects were also recorded during the procedure. RESULTS: The incidence of nausea and vomiting was higher in fentanyl group compared with the other groups. In patients who received fentanyl, the decrease of oxygen saturation at the first and tenth minute of the procedure was statistically significant (p < 0.05). CONCLUSIONS: Diclofenac sodium and tramadol were found to be safe and effective analgesics with lower side-effects than fentanyl.

Diclofenac and metamizol in postoperative analgesia in plastic surgery.

BACKGROUND: Postoperative pain relief after major surgery cannot be achieved with opioids alone in all patients without respiratory depression or other significant drawbacks. Modern medical practice, therefore, dictates the use of alternative analgesic agents as an adjunct or substitute to minimize the deleterious effects and to facilitate an earlier return to work and daily activities. Diclofenac and metamizol inhibit prostaglandin synthesis, thus attenuate the peripheral nociceptive sensitization caused by the surgical trauma. This investigation was conducted to determine the potency of diclofenac compared with metamizol in the control of postoperative pain after various plastic surgical operations under general anesthesia. METHODS: A multiple-dose, randomized, double-blind clinical trial composed of one hundred and sixty-six patients was conducted. Group M patients received 1 g intramuscular metamizol (every 8 hours) and Group D patients received 75 mg intramuscular diclofenac (every 12 hours). Additional analgesia requirements were recorded and meperidine was used as the complementary analgesic when needed. Pain was assessed by visual analogue scores. Platelet count and bleeding time analyses were performed preoperatively and on the first postoperative day. RESULTS: Metamizol decreased the additional analgesia requirement during the 18 hours following surgery. This was also associated with significantly lower pain scores. There was no significant difference between the patients receiving either metamizol or diclofenac in terms of pain scores, additional request for analgesia and frequency of side effects from the 18th until the 48th hour postoperatively. However, the use of diclofenac was associated with reduced side effects, though a reduction in platelet number and prolongation of bleeding time was noted in the majority of the patients receiving diclofenac. CONCLUSIONS: Metamizol is significantly superior to diclofenac for the reduction of postoperative pain after plastic surgery in the first 18 hours after plastic surgery procedures and reduces the need for additional analgesia.

Blood oxidant/antioxidant status of atherosclerotic patients.

In the present study, it is aimed to investigate oxidant/antioxidant status of plasma and erythrocytes from atherosclerotic patients and to establish the possible role of oxidant stress in the formation and progression of atherosclerosis. Antioxidant potential (AOP) values and malondialdehyde (MDA) levels were studied in erythrocyte and plasma samples from 40 atherosclerotic patients and 38 healthy controls. A total of 13 subjects in each group were smokers. AOP was found unchanged in erythrocytes but lower in plasma samples (P<0.0005) from atherosclerotic patients as compared with those of the controls. MDA levels were however higher in erythrocyte hemolysate (P<0.025), erythrocyte membrane (P<0.0005) and blood plasma samples (P<0.0005) from atherosclerotic patients than those of the controls. Moreover, AOP was found to be lower in plasma samples of smoker patients than that of non-smoker patients (P<0.05). In the control group, erythrocyte MDA level was higher in smoker group than that of non-smoker group (P<0.05). Results reveal the presence of oxidant stress in the blood samples from patients with atherosclerosis. It seems antioxidant therapy might give beneficial results for atherosclerotic patients.