Thursday, November 26, 2009

Effect of different anesthetic agents on oculocardiac reflex in pediatric strabismus surgery

Abstract
Purpose The oculocardiac reflex (OCR) occurs frequently during pediatric strabismus surgery. The aim of this study was to assess the effects of various anesthetic regimens on the incidence of OCR during the surgery.
Methods Two hundred and eighty children, 1 to 9 years old, undergoing elective strabismus surgery, were randomly assigned to eight groups; ketamine-sevoflurane (KS), ketamine-desflurane (KD), ketamine-propofol (KP), ketamine-remifentanil (KR), midazolam-sevoflurane (MS), midazolam-desflurane (MD), midazolam-propofol (MP), and midazolam-remifentanil (MR). No premedication was given. Anesthesia was induced using ketamine 1 mg·kg−1 or midazolam 0.15 mg·kg−1 with 66% N2O in O2. Laryngeal mask airways (LMAs) were placed with rocuronium 0.5 mg·kg−1. Anesthesia was maintained with sevoflurane 2–3 vol. %, desflurane 5–6 vol. %, propofol 7–8 mg·kg−1·h−1, or remifentanil 0.75 µg·kg−1 over 1 min, followed by a continuous infusion of remifentanil 0.5 µg·kg−1·min−1 with 66% N2O in O2. Heart rate (HR) was recorded during extraocular muscle (EOM) manipulation. OCR was defined as a reduction in HR of more than 20% induced by the traction of an EOM.
Results In patients given ketamine, OCR occurred more frequently in the KP (65.7%) and KR (62.9%) groups than in the KD (29.4%) and KS (37.1%) groups (P <>P <>
Conclusion Propofol or remifentanil anesthesia was associated with a higher incidence of OCR during pediatric strabismus surgery than sevoflurane and desflurane anesthesia, when either ketamine or midazolam was used as an induction agent.

A comparison of intra-articular magnesium and/or morphine with bupivacaine for postoperative analgesia after arthroscopic knee surgery


Purpose Both magnesium and morphine provide enhanced patient analgesia after arthroscopic knee surgery when administered separately via the intra-articular route. Magnesium sulfate amplifies the analgesic effect of morphine. This study was designed to compare the analgesic effects of intra-articular magnesium and morphine, with bupivacaine, when used separately and in combination.
Methods Eighty patients undergoing arthroscopic menisectomy were randomized blindly into four intra-articular groups: group B+Mor+Mg received 20 ml 0.25% bupivacaine, morphine 2 mg, and magnesium 150 mg; group B+Mor received 20 ml 0.25% bupivacaine and morphine 2 mg; group B+Mg received 20 ml 0.25% bupivacaine and magnesium 150 mg; and group B received 20 ml 0.25% bupivacaine. Pain scores at rest and during movement, analgesic duration, and total analgesic consumption were recorded.
Results Group B+Mor and group B+Mg patients had equally effective postoperative analgesia. Group B+Mor+Mg patients had significantly reduced visual analogue scale (VAS) values both at rest and during movement and significantly increased time to first postoperative analgesic request, as well as significantly reduced total analgesic consumption, compared with the other groups.
Conclusion Intra-articular administration of magnesium sulfate or morphine, with bupivacaine, had comparable analgesic effects in the doses used. Their combination provided more effective postoperative analgesia than either drug alone.

Presurgical fentanyl vs caudal block and the incidence of adverse respiratory events in children after orchidopexy

Background: There is controversy about the etiology of early postoperative hypoxemia. Age, weight, intubation, surgical procedure, use of muscle relaxants, and/or administration of opioids may affect the incidence of early postoperative hypoxemia. In this prospective, randomized, and single-blinded study, we evaluated whether the administration of caudal analgesia vs i.v. fentanyl affected the number of children who develop postextubation adverse upper airway respiratory events, (upper airway obstruction, laryngospasm) and/or early postoperative hypoxemia.

Methods/materials: Institutional approval and written parental informed consents were obtained. Thirty-eight healthy outpatient boys, aged 1–6 years, scheduled for elective orchidopexy were randomized to receive pain relief either with a presurgical caudal block or by i.v. fentanyl. The primary outcome of the study was the number of children who developed postextubation adverse upper airway respiratory events and/or early postoperative hypoxemia.

Results: The number of boys who developed postextubation adverse upper airway respiratory events and/or early postoperative hypoxemia in the caudal group was less compared with those in the fentanyl group (P = 0.04).

Conclusions: Compared to fentanyl, placement of a presurgical caudal block in boys scheduled for orchidopexy was associated with a lower incidence of postextubation adverse upper airway respiratory events and/or early postoperative hypoxemia.

Epidural steroid injections: An update on mechanisms of injury and safety

Epidural steroid injections (ESIs) are the most commonly performed intervention in the United States to manage chronic and subacute low back and neck pain with radiculopathy. ESIs have been used for decades for the treatment of discogenic and osteoarthritic radicular conditions originating from the cervical, thoracic, and lumbar spine, as well as spondylosis, nonspecific radiculitis, and spinal stenosis.

With the ever-increasing use of epidural steroids, there has been a disproportionate increase in popularity of transforaminal ESIs in particular. Since 2002, there has been a growing body of largely transforaminal epidural steroid case report literature that describes paralysis, stroke, and death that immediately follows the performance of these procedures. These complications are thought to be related to a combination of factors, which may include the technique used, underlying pathophysiology that is being treated, anatomical variations in the blood supply, as well as the specific injectate used.

This article discusses the pathogenesis of these complications and puts the role of steroids in their causation into perspective.

Sunday, November 22, 2009

Management of back pain in pregnancy

Back pain during pregnancy is a common problem experienced by many pregnant women. Physiological changes during pregnancy are a contributing factor for the development of back pain. Laxity of the sacroiliac joints causes instability and development of sacroiliac pain. The pain may be severe and can interfere with daily activities. Neurological examination is usually normal. A positive straight leg-rising test may indicate herniated disc, which is rare during pregnancy. Noncontrast magnetic resonance imaging is safe in pregnancy. To date, there are no identified adverse effects of the magnetic resonance on the developing fetus, but long-term effects need to be examined. Most back pain in pregnancy can be treated conservatively. Acetaminophen is the drug of choice to treat pain during pregnancy. Epidural steroid injection (ESI) may be considered in certain cases. Data in the literature are deficient regarding the use of ESI in pregnancy, but it appears to be safe based on expert clinical experience. More work is needed to examine the long-term effect of ESI on the mother and the fetus. Surgery is usually postponed until the postpartum period, unless there is progressive neurological deficits or cauda equina syndrome.

Ultrasound guidance for epidural steroid injections

– Ultrasound (US) guidance is practiced widely in regional anesthesia. It is becoming increasingly used for pain medicine interventions. US–guided neuraxial analgesia has also been demonstrated despite many technical challenges. The applicability of US guidance for neuraxial steroid injections adds the dimension of complications secondary to particulate steroids. This review will discuss the available evidence for the use of US in neuraxial analgesia and for epidural steroid injections (ESIs), the technique and limitations, and the potential uses of US for ESIs.

Friday, November 20, 2009

The Efficacy and Safety of Continuous Intravenous Administration of Remifentanil for Birth Pain Relief: An Open Study of 205 Parturients

OBSTETRIC ANESTHESIOLOGY
In an observational study, we prospectively evaluated the efficacy and safety of remifentanil in 205 parturients. Remifentanil was administered as a continuous infusion. The initial infusion of 0.025 µg · kg–1 · min–1 was increased in a stepwise manner to a maximum dose of 0.15 µg · kg–1 · min–1. Maternal pain, other maternal and fetal variables, side effects, and satisfaction were recorded. The mean (±sd) visual analog score before the start of the infusion was 9.4 ± 1.2 cm and decreased to 5.1 ± 0.4 cm after 5 min and 3.6 ± 1.5 cm after 30 min. The maternal side effects were minimal and no fetal or neonatal side effects were noted.

Thursday, November 19, 2009

Time course of rocuronium-induced neuromuscular block after pre-treatment with magnesium sulphate: a randomised study

Background: A previously published study suggested that pre-treatment with magnesium sulphate (MgSO4) had no impact on the speed of onset of rocuronium-induced neuromuscular block. We set out to verify this assumption.

Methods: Eighty patients (18–60 years) were randomly allocated to MgSO4 60 mg/kg or placebo (saline). Study drugs were given intravenously for 15 min before induction of anaesthesia with propofol, sufentanil and rocuronium 0.6 mg/kg. Anaesthesia was maintained with a target-controlled propofol infusion. Neuromuscular transmission was measured using train-of-four (TOF)-Watch SX® acceleromyography.

Results: Onset was analysed in 37 MgSO4 and 38 saline patients, and recovery in 35 MgSO4 and 37 saline patients. Onset time (to 95% depression of T1) was on average 77 [SD=18] s with MgSO4 and 120 [48] s with saline (P<0.001). The total recovery time (DurTOF0.9) was on average 73.2 [22] min with MgSO4 and 57.8 [14.2] min with saline (P<0.003). The clinical duration (Dur25%) was on average 44.7 [14] min with MgSO4 and 33.2 [8.1] min with saline (P<0.0002). The recovery index (Dur25–75%) was on average 14.0 [6] min with MgSO4 and 11.2 [5.2] min with saline (P<0.02). The recovery time (Dur25%TOF0.9) was on average 28.5 [11.7] min with MgSO4 and 24.7 [8.4] min with saline (P=0.28).

Conclusion: Magnesium sulphate given 15 min before propofol anaesthesia reduces the onset time of rocuronium by about 35% and prolongs the total recovery time by about 25%.

Wednesday, November 18, 2009

Malignant Hyperthermia - Diagnostics, Treatment and Anaesthetic Management

In malignant hyperthermia (MH) susceptible individuals volatile anaesthetics and the depolarizing muscle relaxant succinylcholine may induce a potentially lethal hypermetabolic syndrome of skeletal muscle due to an uncontrolled sarcoplasmic calcium release. Immediate discontinuation of triggering agents, oxygenation, correction of acidosis and electrolyte abnormalities and dantrolene application are essential for MH treatment. This article reviews the clinical symptoms of MH, the diagnostic criteria and the actual guidelines for treatment and management of anaesthesia in susceptible individuals.

Tuesday, November 17, 2009

Ketamine, but not priming, improves intubating conditions during a propofol–rocuronium induction

Purpose Both ketamine and priming may shorten the onset time of rocuronium. This study investigates the effects of ketamine and priming as components of a propofol induction on intubating conditions and onset of neuromuscular block.
Methods This prospective randomized double-blind study was performed in 120 American Society of Anesthesiologists (ASA) I–II patients who were assigned to one of four groups of 30 patients each: control, priming, ketamine, and ketamine-priming. Ketamine 0.5 mg ∙ kg−1 or saline was given before priming and induction. Rocuronium 0.06 mg ∙ kg−1 or saline was injected 2 min before propofol 2.5 mg ∙ kg−1. This was followed by rocuronium 0.6 mg ∙ kg−1 or by rocuronium 0.54 mg ∙ kg−1 if priming was given. Intubation was performed one minute later. Intubating conditions were graded as excellent, good, or poor. Heart rate, noninvasive blood pressure, and train-of-four (TOF) response were monitored.
Results Intubating conditions were graded excellent in 20% of the control group, 30% of the priming group, 47% of the ketamine group, and 57% of the ketamine-priming group. Analysis using forward stepwise regression indicated that ketamine improved intubating conditions (P = 0.001) but priming did not (P = 0.35). Time to reach a TOF count of zero was shortened by ketamine (P = 0.001) but not by priming (P = 0.94): 216 ± 20 s in the control group, 212 ± 27 s in the priming group, 162 ± 18 s in the ketamine group, and 168 ± 22 s in the ketamine-priming group.
Conclusion A low-dose ketamine used with a propofol–rocuronium induction improved intubating conditions and shortened onset time. Priming did not influence intubating conditions or onset time.

Monday, November 16, 2009

Tracheal intubation in patients with rigid collar immobilisation of the cervical spine: a comparison of Airtraq® and LMA CTrach™ devices*

The aim of this study was to evaluate the effectiveness of the Airtraq® and CTrach™ in lean patients with simulated cervical spine injury after application of a rigid cervical collar. Eighty-six consenting adult patients of ASA physical status 1 or 2, who required elective tracheal intubation were included in this study in a randomised manner. Anaesthesia was induced using 1 μg.kg−1 fentanyl, 3 mg.kg−1 propofol and 0.6 mg.kg−1 rocuronium, following which a rigid cervical collar was applied. Comparison was then made between tracheal intubation techniques using either the AirTraq or CTrach device. The mean (SD) time to see the glottis was shorter with the Airtraq than the CTrach (11.9 (6.8) vs 37.6 (16.7)s, respectively; p < 0.001). The mean (SD) time taken for tracheal intubation was also shorter with the Airtraq than the CTrach (25.6 (13.5) and 66.3 (29.3)s, respectively; p < 0.001). There was less mucosal damage in the Airtraq group (p = 0.008). Our findings demonstrate that use of the Airtraq device shortened the tracheal intubation time and reduced the mucosal damage when compared with the CTrach in patients who require cervical spine immobilisation.

Thursday, November 12, 2009

Comparison of the laryngeal mask airway Supreme and laryngeal mask airway Classic in adults

Background and objective: The laryngeal mask airway (LMA) is an important airway device that was developed in 1983. From the first classic LMA models up to now, LMA models have been developed that are easily and quickly inserted, provide ventilation at higher airway pressures, have lower cuff pressure, a reduced risk of gastric aspiration and cause fewer stress responses. We aimed to compare the LMA Classic with the LMA Supreme in assessing the success rate and time for insertion, number of attempts and leak pressure.

Methods: A total of 70 patients of ASA group I or II were included in our study. Regarding the airway device used during surgery, the patients were randomly assigned into two groups: the LMA Supreme group and the LMA Classic group. In order to provide common conditions for inserting the laryngeal mask, insertion was made while the bispectral index was between 50 and 60 and T1 was 0. The success rate of inserting the LMA, the duration of insertion, the number of attempts, the insertion complications, ventilation parameters, haemodynamic parameters and postoperative adverse effects were recorded for each group.
Results: In the LMA Classic group and the LMA Supreme group, the LMA was successfully inserted in 27 (88.5%) and 34 (97%) patients, respectively. The duration of insertion in the LMA Supreme group was shorter and the cuff pressure was lower than that in the LMA Classic group (P < 0.001).

Conclusion: The LMA Supreme is superior to the LMA Classic because of its ease of insertion with low cuff pressure and high oropharyngeal leakage pressure

Sexuality During Pregnancy

Introduction. Sexuality is an important part of health and well-being. Sexual behavior modifies as pregnancy progresses, influenced by biological, psychological, and social factors.

Aim. To evaluate changes in sexual perceptions and activities during pregnancy and to determine sexual dysfunctions in that period.

Main Outcome Measures. Sexual perceptions (desire from the partner, feelings of attractiveness, and fear of sexual intercourse), sexual activities during pregnancy (sexual intercourse frequency, the most frequent sexual intercourse trimester, sexual activity during the birth week, type(s) of sexual intercourse, changes in sexual satisfaction and desire compared with the pre-pregnancy period, and changes in sexual intercourse frequency during each trimester compared with the pre-pregnancy period), and sexual dysfunctions.

Methods. Puerperal women were asked to anonymously complete a self-administered and structured questionnaire at the day of discharge from hospital.

Results. One hundred and eighty-eight women, aged between 17 years and 40 years with a mean age of 28.9 years, were analyzed. The first trimester was considered the most frequent period of sexual intercourse (44.7%), followed by the second trimester (35.6%). Fifty-five percent reported a decrease of sexual activity during the third trimester. Fear of sexual intercourse was referred by 23.4% of the women questioned. Sexual satisfaction was unchanged in 48.4% of the subjects and decreased in 27.7% (P < 0.0001); sexual desire is reported to be unchanged in 38.8% and decreased in 32.5% (P = 0.196) of the population. Vaginal, oral, anal sex, and masturbation were performed by 98.3%, 38.1%, 6.6%, and 20.4% of the women, respectively.

Conclusions. We determined in our study that sexual satisfaction do not change in pregnancy compared with the pre-pregnancy patterns despite a decline of sexual activity during the third trimester. A discussion of expected changes in sexuality should be routinely done by the doctor in order to improve couples' perception of possible sexual modifications induced by pregnancy. Pauleta JR, Pereira NM, and Graça LM. Sexuality during pregnancy. J Sex Med **;**:**–**.

Wednesday, November 11, 2009

The effect of intrathecal fentanyl on Cerebral State Index-guided sedation during spinal anaesthesia*

This study investigated the effect of intrathecal fentanyl on the dose of propofol during sedation guided by Cerebral State Index monitoring. Seventy patients were randomly assigned to receive either fentanyl 25 μg (n = 35) or normal saline (n = 35) with hyperbaric bupivacaine 12.5 mg for spinal anaesthesia. Propofol was infused to maintain a Cerebral State Index value of 65–75 for 30 min. The propofol infusion time and dose required to reach a Cerebral State Index value of 75 were recorded together with the time required to reach a Cerebral State Index value higher than 90 after cessation of sedation. The onset time for sedation was faster and the recovery time was slower in the fentanyl group compared to those in the saline group (p = 0.018 and 0.027, respectively). The propofol doses required for onset and maintenance of sedation were significantly lower in the fentanyl group compared to those in the control group (p = 0.018 and < 0.001, respectively). In conclusion, adding intrathecal fentanyl 25 μg during spinal anaesthesia significantly reduced the dose of propofol required for sedation and prolonged the subsequent recovery time.

Tuesday, November 10, 2009

Perioperative pain management in the patient treated with opioids: Continuing Professional Development

Purpose The objective of this continuing professional development module is to describe the perioperative anesthesia and pain management of patients taking opioids because of chronic pain or drug addiction.
Principal findings The number of patients under opioid treatment is increasing. Pain management is problematic in these patients, because regular opioid intake is associated with mechanisms of tolerance and dependence. More recently, opioid-induced hyperalgesia phenomena have been brought to light. As a rule, the usual opioid dose should be administered with the appropriate conversions, and additional requirements should be anticipated because of the surgical procedure. Local and regional anesthesia, and multimodal analgesia are indicated whenever possible. For the patient addicted to heroin or other opioids, the perioperative period is not a suitable time to initiate weaning.
Conclusion The physiological and pharmacological changes caused by chronic opioid intake must be understood in order to provide optimal pain management with respect to each individual and the type of procedure.

Inotrope and Vasopressor Therapy of Septic Shock

When fluid administration fails to restore an adequate arterial pressure and organ perfusion in patients with septic shock, therapy with vasoactive agents should be initiated. The ultimate goals of such therapy in shock are to restore effective tissue perfusion and to normalize cellular metabolism. The efficacy of hemodynamic therapy in sepsis should be assessed by monitoring a combination of clinical and hemodynamic parameters. Although specific end points for therapy are debatable, and therapies will inevitably evolve as new information becomes available, the idea that clinicians should define specific goals and end points, titrate therapies to those end points, and evaluate the results of their interventions on an ongoing basis remains a fundamental principle.

Monday, November 9, 2009

Depth of anesthesia

– The present review article provides a summary of the recent literature evaluating the technology for monitoring depth of anesthesia and patient outcomes associated with its use. The goal of precisely dosed general anesthesia guided by brain monitoring remains elusive.

Ultrasound-guided arterial catheterization: a narrative review

– A description of the procedure is provided, along with an online supplemental video. Most studies indicate that first–pass success will be improved with US–guided (USG) arterial catheterization. The technique is easy to learn, particularly if one is already familiar with USG for central venous catheter placement. More research, including formal analyses of cost effectiveness, is needed.
Abstract Arterial catheterization is the second most common invasive procedure performed in the intensive care unit. Despite the ubiquity of the procedure, complications including failure to place the catheter occur. While many clinicians are familiar with the use of ultrasound (US) guidance to decrease complication rates of central venous catheter insertion, fewer are familiar with the use of ultrasound to guide arterial catheterization. This manuscript reviews the evidence for the utility of ultrasound for this indication. Technical aspects of the procedure and limitations of the existing evidence are reviewed. A description of the procedure is provided, along with an online supplemental video. Most studies indicate that first-pass success will be improved with US-guided (USG) arterial catheterization. The technique is easy to learn, particularly if one is already familiar with USG for central venous catheter placement. More research, including formal analyses of cost effectiveness, is needed.
Electronic supplementary material The online version of this article (doi:10.1007/s00134-009-1699-6) contains supplementary material, which is available to authorized users.
Keywords Catheterization - Artery - Ultrasonography - Review

Wednesday, November 4, 2009

Use of oral ketamine in chronic pain management: A review

The analgesic effect of ketamine is primarily based on the antagonism of the N-methyl-D-aspartate (NMDA) receptor. Activation of NMDA receptors may play a crucial role in the pathogenesis of chronic pain. Little formal research has been performed on the efficacy and safety of ketamine in chronic pain, especially concerning long-term oral administration. This review provides an overview of the available clinical data on the use of oral ketamine in chronic pain management. A literature search was performed in MEDLINE, EMBASE and the Cochrane Library, resulting in 22 relevant articles. Because most retrieved articles were of a descriptive nature (e.g. case reports and case series) a quantitative analysis was not possible. There was no consistent dose–response relation. A recommended starting dosage in ketamine-naive patients is 0.5mg/kg racemic ketamine or 0.25mg/kg S-ketamine as a single oral dose. The dosage is increased by the same amount if required. For a continuous analgesic effect it is usually given 3–4 times daily. The injection fluid can be taken orally. When parenteral ketamine is switched to oral administration the daily dosage can be kept equal and, depending on clinical effect and/or adverse effects, is slowly increased. The pharmacologically active metabolite norketamine is believed to contribute to the analgesic effect of oral ketamine. Lack of evidence regarding efficacy, and the poor safety profile, do not support routine use of oral ketamine in chronic pain management. Oral ketamine may have a limited place as add-on therapy in complex chronic pain patients if other therapeutic options have failed.

Total intravenous anaesthesia techniques for ambulatory surgery

-Purpose of review: The purpose of the present review is to provide an updated discussion on the use of total intravenous anaesthesia (TIVA) for ambulatory surgery, based on results from recent studies put into the context of issues already known.

Recent findings: The current use of TIVA for ambulatory surgery seems to be abundant. It is encouraged by the simplicity of the method, increased experience and declining costs with the propofol and remifentanil combination. The TIVA methods are well tolerated and perceived to give good quality patient care; with rapid, clear-headed emergence and low incidence of postoperative nausea and vomiting. Cost-efficacy and other benefits of recovery from TIVA versus alternative techniques of anaesthesia seem to depend more on the patient and the individual perioperative setting than on the TIVA concept per se. Further development of TIVA will include the refinement of target control systems, the introduction of new drugs and adjuvants and advanced equipment for automatic drug delivery, as well as improved effect monitoring.

Summary: TIVA is well tolerated and simple. It is associated with less postoperative nausea and vomiting than inhalational anaesthesia and has no residual paralyses as are possible with locoregional techniques. Propofol with remifentanil seems to be the dominating TIVA technique, delivered either by conventional pumps or by target control systems.