Acta Anaesthesiologica Taiwanica

Inhalational anesthetic agents in postoperative cognitive dysfunction

Chih-Cherng Lu, Wen-Jinn Laiw, Shung-Tai Ho — 2011-12-26

Advancement of health care and continuous improvement of perioperative medicine which result in reduction of surgical mortality and morbidity have led to an exponential increase in the safety of surgery. The number of elderly patients undergoing surgical procedures is progressively increasing, and postoperative cognitive decline in these patients has emerged as a major health concern. Postoperative cognitive dysfunction (POCD) refers to cognitive problems that involve memory, learning, and the ability to concentrate after surgery. In 1982, Savageau first described cognitive dysfunction, which had a strong association with surgery and anesthesia exposure. Particularly among the elderly, a number of cases with short-term or long-term POCD have been globally reported.

Equal volumes of undiluted nalbuphine and lidocaine and normal diluted saline prevents nalbuphine-induced injection pain

2011-12-26

Abstract: Objectives: To determine if the intravenous co-administration of equal volumes of lidocaine and nalbuphine, with undiluted normal saline, prevents injection pain caused by nalbuphine.Methods: Eighty adult patients who were scheduled for minor surgeries under general anesthesia delivered via a laryngeal mask airway (LMA) were enrolled in this prospective, randomized, single-blind clinical trial. In the saline group (control) (n = 40), 1 mL (10 mg) nalbuphine was diluted with 9 mL normal saline. In the lidocaine group (experimental) (n = 40), 1 mL (10 mg) nalbuphine was diluted with 1 mL lidocaine (20 mg). The two respective nalbuphine solutions were injected into the cephalic vein at a rate of 20 mL/minute (0.33 mL/second). Pain scores were categorized into five grades. Pain responses upon intravenous injection of nalbuphine, site of cannulation, size of the catheter, and hemodynamic responses to nalbuphine were also recorded.Results: Overall, the median pain score of patients in the lidocaine group was lower than that of the saline group (p < 0.001). In addition, the incidence of injection pain was lower in the lidocaine group than the saline group (2.5% vs. 30%, p = 0.001).Conclusion: A solution of equal volumes of lidocaine and nalbuphine can decrease intravenous nalbuphine-induced injection pain.

Closed-loop isoflurane administration with bispectral index in open heart surgery: Randomized controlled trial with manual control

J. Sethu Madhavan, G.D. Puri, Preethy J. Mathew — 2011-12-26

Abstract: Objective: Improved anesthetic agent delivery system (IAADS), a modification of closed-loop anesthesia delivery system (CLADS), is designed to deliver inhalational anesthetics and propofol through closed-loop control with bispectral index (BIS) as target. We compared the performance of IAADS with the manual control isoflurane administration during cardiac surgery.Methods: Forty patients of ASA (American Society of Anesthesiologists) physical status class II–III, undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) in a tertiary care hospital in India were randomized to receive isoflurane through a closed-loop system (IAADS group) or through a Tech 7 vaporizer adjusted manually (manual group) to achieve a target BIS of 50. Patients were induced with a propofol infusion and isoflurane was started after intubation. During CPB, patients received propofol; isoflurane was restarted after separation from CPB. The efficacy of IAADS in controlling depth of anesthesia and hemodynamic variations was compared with that of manual control.Results: IAADS was able to maintain BIS within ± 10 of target for significantly longer period (84.6 ± 7.2% in IAADS group vs. 75.9 ± 11.2 in manual group, p < 0.01). Both overall performance, as assessed by global score (p < 0.01), and precision, as judged by median absolute performance error (MDAPE) (p < 0.04), were significantly better in the IAADS group. The IAADS group required significantly less propofol for induction (1.3 ± 0.4 mg/kg in IAADS vs. 1.6 ± 0.5 mg/kg in manual, p < 0.05) and less isoflurane during maintenance of anesthesia (3.3 ± 0.8 ml/h vs. 3.4 ± 0.9 ml/h, p < 0.01).Conclusion: The present study proves the feasibility and efficacy of inhalation anesthetic administration through closed-loop control. This is the first system that has been developed to control intravenous and inhalational anesthetic agents in a closed-loop model using BIS.

Use of laryngeal mask airway in children with upper respiratory tract infection, compared with face mask: Randomized, single blind, clinical trial

2011-12-19

Abstract: Objective: The incidence of postoperative cough (primary outcome) and adverse respiratory events (secondary outcome) in children who received anesthesia by laryngeal mask airway (LMA) with children who received anesthesia by face mask (FM) was compared in a blind randomized trial with uncomplicated upper respiratory track infection (URI) undergoing general anesthesia. Previous studies of pediatric patients with URI receiving anesthesia by endotracheal tube have reported a greater number of anesthetic complications; however reports concerning adverse effects in pediatric patients with URI receiving anesthesia by LMA or FM are scanty.Method: For the present trial, 150 children with uncomplicated URI and requiring general anesthesia for ophthalmic procedures were enrolled. Once the severity of preoperative URI symptoms was stratified, the children were randomized to receive general anesthesia by FM or LMA. Anesthesia was induced with sevoflurane and nitrous oxide in oxygen (N2O in O2). Respiratory adverse events were evaluated peri- and post-operatively.Results: The two groups did not differ in age, weight, American Society of Anesthesiologists (ASA) physical status, sex, duration of surgery or severity of URI symptoms. The incidences of cough (19% in LMA vs. 42% in FM), vomiting (4% in LMA vs. 12% in FM) and intervention to maintain the patency of the airway were statistically higher in the FM group (p<0.05). There were no differences between the two groups with respect to the incidences of apnea, laryngospasm, desaturation, bronchospasm, readmission and sore throat.Conclusion: In children with uncomplicated URI, the administration of inhalation anesthetics in general anesthesia by LMA is likely to cause fewer adverse events than the use of FM.

Peribulbar block in 500 patients scheduled for eye procedures and treated with acetyl salicylic acid

2011-12-26

Abstract: Objectives: No guidelines are available in France for peribulbar block for eye procedures. It is our hypothesis that continued use of acetyl salicylic acid for forestalling myocardial or cerebrovascular ischemic events does not increase the risk of hemorrhage, compared with discontinuation of its use in patients who undergo eye procedures under peribulbar block.Methods: For this prospective control study we enrolled two groups of 500 patients scheduled for intra-ocular eye surgery requiring a peribulbar block. Patients treated with acetyl salicylic acid were included in group A (500 patients). Patients who had never been treated with acetyl salicylic acid constituted the control group (group B: 500 patients). Hemorrhages were graded as follows: 1=spot ecchymosis; 2=lid ecchymosis involving half of the lid surface area or less; 3=lid ecchymosis all around the eye, without increase in intra-ocular pressure; 4=retrobulbar hemorrhage with increased intraocular pressure.Results: In group A, lid hemorrhages (grade 1) were observed in 30 patients (6.0%). No grade 2, 3 or 4 hemorrhages were encountered in this group. In group B, lid hemorrhage (grade 1) was observed in 20 patients (4.0%) and grade 2 in one patient (0.2 %), but no grade 3 or 4 hemorrhages were encountered. Statistical tests showed the absence of significance between both groups.Conclusion: We conclude that between the groups with and without pre-operative acetyl salicylic acid the occurrence rate of lid hemorrhage was not significant in peribulbar block.

Biphasic effects of chronic intrathecal gabapentin administration on the expression of protein kinase C gamma in the spinal cord of neuropathic pain rats

Chin-Yi Yeh, Shih-Chieh Chung, Fan-Ling Tseng, Yu-Chuan Tsai, Yen-Chin Liu — 2011-12-26

Abstract: Objectives: Patients suffering from neuropathic pain are difficult to treat and many methods are used to resolve this issue. In this study, we used a model of neuropathic pain comprising rats with chronic constriction injury (CCI) on the left sciatic nerve to investigate the chronic effect of gabapentin via intrathecal administration. We also observed the expression of dorsal spinal protein kinase C gamma subunit (PKCγ) and other pain-related molecules in the spinal area which included cyclooxygenase 2 (COX2), c-Fos and cyclic AMP-dependent transcription factor (ATF3) in the neuropathic pain animals.Methods: Male Sprague-Dawley (SD) rats (250–380g) were randomly assigned to four groups, i.e., control, gabapentin (Gaba), MK801, and gabapentin plus MK801 (Gaba+M) groups. A PE-5 catheter was inserted into the lumbar spine area via the cervical spine area. CCI was performed the following day after the intrathecal catheter implant surgery. Gabapentin (1.05μmol/day) was then given the following day after CCI surgery. Intrathecal gabapentin was administrated for 14 consecutive days. Pain-related behavior was assessed every 2 days thereafter by measuring the latency of foot withdrawal elicited by noxious radiant heat or Von Frey microfilament applied to the hind-paw plantar surface. MK801 (30μg/day), an N-methyl-D-aspartate (NMDA) receptor blocker, was also added for potential effect. The tissue of dorsal horn of the lumbar spine was harvested on the 14th day for the expression of COX2, c-Fos, ATF3 and PKCγ with Western blotting, and positive finding protein was then checked on 7th day for further evaluation.Results: The beneficial effect of intrathecal gabapentin of statistic significance on thermal duration and mechanical microfilament appeared after 7-day and 11-day consecutive treatment, respectively. Furthermore, the NMDA receptor blocker also potentiated the effect on the behavior of thermal and mechanical stimulations. Gabapentin had no effect on the expression of COX2, c-Fos and ATF3. Interestingly, the expression of PKCγ in the spinal cord was initially inhibited by gabapentin on the 7th day but was potentiated on the 14th day.Conclusions: Our results indicate that chronic intrathecal gabapentin has beneficial effects on the behaviors of both thermal and mechanical stimulations in the neuropathic pain animals and the NMDA blocker can potentiate this effect. Furthermore, gabapentin has biphasic effect on the expression of PKCγ in the spinal cord on Day 7 and Day 14 for the model rats with CCI.

Do inhalational anesthetics cause cognitive dysfunction?

Rele Ologunde, Daqing Ma — 2011-12-21

Abstract: Increasing evidence indicates that inhalational anesthetics may cause or increase the risk of developing postoperative cognitive dysfunction (POCD), especially in the elderly population. POCD may exist as a transient or long-term complication of surgery and anesthesia and is associated with reduced quality of life. There remains great discrepancy between clinical studies investigating the prevalence of POCD and inhalational anesthetics as many fail to show an association. However, numerous animal studies have suggested that inhalational anesthetics may alter cognitive function via amyloid β accumulation, modified neurotransmission, synaptic changes and dysregulated calcium homeostasis. Other factors such as neuroinflammation and pro-inflammatory cytokines may also play a role. This paper reviews the role of inhalational anesthetics in the etiology and underlying mechanisms that result in POCD.

Hemodynamic monitoring and outcome—A physiological appraisal

Yoo-Kuen Chan, Zahid Hussain Khan — 2011-12-21

Abstract: Hemodynamic monitoring provides us with refined details about the cardiovascular system. In spite of increased availability of the monitoring process and monitoring equipment, hemodynamic monitoring has not significantly improved survival outcome. Care providers should be cognizant of the role of the cardiovascular system and its importance in oxygen delivery to the cells in order to sustain life. Effective hemodynamic monitoring should be able to delineate how well the system is performing in carrying out this role. Different hemodynamic monitors serve in this role to a different extent; some provide very little information on this. The cardiovascular system is only one of the many systems that need to function optimally for survival; others of equal importance include the integrity of the airway, the breathing process, the adequacy of hemoglobin level, and the health of the tissue bed, especially in the brain and the heart. Advances in hemodynamic monitoring with focus on oxygen delivery at the cellular level may ultimately provide the edge to effective monitoring that can impact outcome.

Trachway intubating stylet for tracheal intubation in an ankylosing spondylitis patient undergoing total hip replacement under general anesthesia

2011-12-19

Abstract: The Trachway is a new device which provides better glottic view than conventional direct laryngoscopy during tracheal intubation. This intubating stylet consists of a camera on the distal tip of the style, with a monitor attached to the rechargeable handle, so that it can overcome the difficulty of limited neck motion and mouth opening in tracheal intubation. We present here a 54-year-old man with ankylosing spondylitis, scheduled to undergo total hip replacement. Pre-operative airway assessment revealed a recognized difficult airway. The Trachway was successfully used for oral tracheal intubation at the first attempt. The Trachway can be an alternative choice for intubation in ankylosing spondylitis patients.

Interference of patent blue dye with pulse oximetry readings, methemoglobin measurements, and blue urine in sentinel lymph node mapping: A case report and review of the literature

2011-12-21

Abstract: Patent blue (PB) dye has been successfully used worldwide in breast and cervix surgeries with few complications. Interference of oxyhemoglobin saturation reading by pulse oximetry (SpO2) and methemoglobinemia, from injection of PB dye, have rarely been reported in breast and cervix surgeries. We report here the first case of interference of SpO2 reading, advent of methemoglobinemia, and blue urine from the use of PB dye, which occurred concurrently in a female undergoing bilateral modified radical mastectomy. The unexpected events might be a consequence of excessive administration of PB dye. We also reviewed the published discourses in literature on the adverse effects of PB dye.

Incidence of cardiac arrest increases with the indiscriminate use of dexmedetomidine: A case series and review of published case reports

Saswata Bharati, Anirban Pal, Chaitali Biswas, Rajasree Biswas — 2011-12-21

Abstract: Dexmedetomidine has predictable, complex, and negative cardiovascular effects that lead to additional adverse effects such as bradycardia and hypotension in up to 42% of patients and might cause profound left ventricular dysfunction and refractory shock. Usually, these temporary effects can be successfully counteracted with atropine, ephedrine, and volume supplementation. Clinicians need to be well informed about the potential of dexmedetomidine to cause bradycardia, which may progress to pulseless electrical activity, particularly in patients older than 50 years and patients with cardiac abnormalities. Here, we report the clinical characteristics of six patients who were scheduled for various neurosurgical procedures within a period of three months and suffered from cardiac arrest following dexmedetomidine administration. We urge clinicians to take caution against the negative effects of dexmedetomidine, especially when it is used in patients older than 50 years with underlying cardiac disease and in combination with cardiodepressant drugs.