New Research In Anesthesia 3/2015

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Specializes in Anesthesia.

Hi Everyone,

I thought I would start a new research in anesthesia summary about once a month. Please, feel free to add any interesting articles that you feel are current and relevant.

Penn Medicine Researchers Discover Possible New General Anesthetics

Findings hold potential for development of first new anesthetics in 40 years

Penn Medicine Researchers Discover Possible New General Anesthetics

Abstract

Background and Objectives: Perineural dexamethasone prolongs the duration of single-injection peripheral nerve block when added to the local anesthetic solution. Postulated systemic mechanisms of action along with theoretical safety concerns have prompted the investigation of intravenous dexamethasone as an alternative, with decidedly mixed results. We aimed to confirm that addition of intravenous dexamethasone will prolong the duration of analgesia after single-injection supraclavicular block compared with conventional long-acting local anesthetic alone or in combination with perineural dexamethasone for ambulatory upper extremity surgery.

Methods: Seventy-five patients were randomized to receive supraclavicular block using 30-mL bupivacaine 0.5% alone (Control), with concomitant intravenous dexamethasone 8 mg (DexIV), or with perineural dexamethasone 8 mg (DexP). Duration of analgesia was designated as the primary outcome. To test our hypothesis, the superiority of DexIV was first compared with Control and then with DexP. Motor block duration, pain scores, opioid consumption, opioid-related side effects, patient satisfaction, and block-related complications were also analyzed.

Results: Twenty-five patients per group were analyzed. The duration of analgesia (mean [95% confidence interval]) was prolonged in the DexIV group (25 hours [17.6–23.6]) compared with Control (13.2 hours [11.5–15.0]; P

Conclusions: In a single-injection supraclavicular block with long-acting local anesthetic, the effectiveness of intravenous dexamethasone in prolonging the duration of analgesia seems similar to perineural dexamethasone.

Intravenous Dexamethasone and Perineural Dexamethasone Simil... : Regional Anesthesia and Pain Medicine

Abstract

Background and Objectives: The comparative incidences of hemidiaphragmatic paralysis associated with contemporary ultrasound-guided supraclavicular versus infraclavicular blockade have not received extensive study. We tested the hypothesis that the infraclavicular approach results in a lower incidence of hemidiaphragmatic paralysis compared with supraclavicular blockade when a standard local anesthetic volume and concentration are used.

Methods: With institutional human ethics board approval, we enrolled 64 patients undergoing right-sided upper extremity surgery in a randomized, blinded, parallel-group trial. Patients were assigned to ultrasound-guided supraclavicular or infraclavicular blockade with 30 mL of 0.5% ropivacaine. The primary end point was complete hemidiaphragmatic paralysis at 30 minutes, defined as a greater than 75% reduction in diaphragmatic excursion measured with the voluntary sniff test using M-mode ultrasonography. Partial paralysis was defined as a 25% to 75% reduction.

Results: Eleven (34%) of 32 patients in the supraclavicular group versus 1 (3%) of 32 in the infraclavicular group had complete hemidiaphragmatic paralysis (P = 0.001 [1-tailed]; relative risk, 11.0 [95% confidence interval, 1.5–80.3]); 44% versus 13% had any (complete or partial) paralysis (P = 0.006; relative risk, 3.5 [95% confidence interval, 1.3–9.5]). Eight (25%) of 32 patients in the supraclavicular group versus 5 (16%) of 32 in the infraclavicular group reported dyspnea (P = 0.54).

Conclusions: Ultrasound-guided supraclavicular blockade with 30 mL of 0.5% ropivacaine produced complete hemidiaphragmatic paralysis in approximately one-third of patients. The infraclavicular approach greatly reduced this risk but did not eliminate it. These data may aid in the selection of the approach to brachial plexus blockade, particularly in ambulatory patients and/or those with respiratory comorbidities.

Hemidiaphragmatic Paralysis Following Ultrasound-Guided Supr... : Regional Anesthesia and Pain Medicine

Abstract

BACKGROUND:

Insufficient fasting prior to endoscopic procedures performed under sedation may result in potential aspiration of gastric contents. Fasting as per ASA guidelines is recommended prior to these procedures. However, the effect of chewing gum on fasting status has been a subject of debate and often leads to procedural delays.

OBJECTIVE:

Evaluation of the effect of chewing gum on the gastric volume and pH.

METHODS:

In this randomized controlled prospective observer blinded trail, ASA I-III patients aged more than 18 years scheduled for esophagogastroduodenoscopy (EGD) or a combined EGD and colonoscopy under conscious sedation were studied. Patients randomized to the chewing gum group (Group-C) were allowed to chew gum until just before the start of their procedure; the remaining patients were included into Group-NC. After sedation and endoscope insertion, stomach contents were aspirated under vision of a gastroenterologist (blinded to groups).

RESULTS:

Volume and pH of gastric contents aspirated from 67 patients (34 in Group-C and 33 in Group-NC) were analyzed. The demographic parameters of the groups were comparable. Gastric volume (median-interquartile range) was statistically higher in Group-C (13 ml (7.75-40.75) vs Group-NC 6 ml (1.00-14.00) (P

CONCLUSION:

Although our results show gastric volume in patients chewing gum was statistically higher, clinical relevance of such a small difference is questionable. Thus patients who chewed gum inadvertently prior to procedure should not be denied or delayed administration of sedative and anesthetic medications.

Effect of Gum Chewing on the Volume and pH of Gastric Contents: A P... - PubMed - NCBI

[h=2]Abstract[/h]Objectives Childhood asthma is a complex condition where many environmental factors are implicated in causation. The aim of this study was to complete a systematic review of the literature describing associations between environmental exposures and the development of asthma in young children.

Setting A systematic review of the literature up to November 2013 was conducted using key words agreed by the research team. Abstracts were screened and potentially eligible papers reviewed. Papers describing associations between exposures and exacerbation of pre-existing asthma were not included. Papers were placed into the following predefined categories: secondhand smoke (SHS), inhaled chemicals, damp housing/mould, inhaled allergens, air pollution, domestic combustion, dietary exposures, respiratory virus infection and medications.

Participants Children aged up to 9 years.

Primary outcomes Diagnosed asthma and wheeze.

Results 14 691 abstracts were identified, 207 papers reviewed and 135 included in the present review of which 15 were systematic reviews, 6 were meta-analyses and 14 were intervention studies. There was consistent evidence linking exposures to SHS, inhaled chemicals, mould, ambient air pollutants, some deficiencies in maternal diet and respiratory viruses to an increased risk for asthma (OR typically increased by 1.5–2.0). There was less consistent evidence linking exposures to pets, breast feeding and infant dietary exposures to asthma risk, and although there were consistent associations between exposures to antibiotics and paracetamol in early life, these associations might reflect reverse causation. There was good evidence that exposures to house dust mites (in isolation) was not associated with asthma risk. Evidence from observational and intervention studies suggest that interactions between exposures were important to asthma causation, where the effect size was typically 1.5–3.0.

Conclusions There are many publications reporting associations between environmental exposures and modest changes in risk for asthma in young children, and this review highlights the complex interactions between exposures that further increase risk.

A systematic review of associations between environmental exposures and development of asthma in children aged up to 9 years -- Dick et al. 4 (11) -- BMJ Open

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