Effect of Interscalene Brachial Plexus Block on the Pulmonary Function of Obese Patients: A Prospective, Observational Cohort Study.

Background: The effect of interscalene block (ISB) on pulmonary function of obese participants has not been investigated. The goal of this study is to assess the association of obesity (body mass index [BMI] >29 kg/m vs BMI <25 kg/m) and change in forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) after ISB in participants undergoing outpatient shoulder surgery.

Methods: This prospective, observational cohort study compared obese (BMI >29 kg/m) and normal-weight (BMI <25 kg/m) groups undergoing ISB for ambulatory shoulder surgery, on preblock and postblock FVC and FEV1, at 30 minutes postblock and in the postanesthesia care unit (PACU).

Changes in Brain Resting-state Functional Connectivity Associated with Peripheral Nerve Block: A Pilot Study.

Background: Limited information exists on the effects of temporary functional deafferentation (TFD) on brain activity after peripheral nerve block (PNB) in healthy humans. Increasingly, resting-state functional connectivity (RSFC) is being used to study brain activity and organization. The purpose of this study was to test the hypothesis that TFD through PNB will influence changes in RSFC plasticity in central sensorimotor functional brain networks in healthy human participants.

Long-acting serotonin antagonist (Palonosetron) and the NK-1 receptor antagonists: does extended duration of action improve efficacy?

In a growing outpatient surgical population, postdischarge nausea and vomiting (PDNV) is unfortunately a common and costly anesthetic complication. Identification of risk factors for both postoperative nausea and vomiting and PDNV is the hallmark of prevention and management. New pharmacologic interventions with extended duration of action, including palonosetron and aprepritant, may prove to be more efficacious.

New medications and techniques in ambulatory anesthesia.

Novel anesthetic and analgesic agents are currently under development or investigation to improve anesthetic delivery and patient care. The pharmacokinetic and analgesic profiles of these agents are especially tailored to meet the challenges of rapid recovery and opioid minimization associated with ambulatory anesthesia practice.

Peripheral nerve stimulation in regional anesthesia.

Peripheral nerve stimulation has a long history in regional anesthesia. Despite the advent of ultrasound-guided peripheral nerve blockade, nerve stimulation remains a popular technique used alone or, now, in combination with ultrasound-guided techniques. In light of this evolving utility of nerve stimulation, this is an appropriate time to review the basic concepts and knowledge base of this historically important tool.

Management of postdischarge nausea and vomiting after ambulatory surgery.

Purpose Of Review: Although there are extensive studies of postoperative and postdischarge nausea and vomiting (PONV/PDNV) up to 24  h, few investigate 'delayed PDNV'. With an increasing outpatient surgical population, specific 'delayed PDNV' risk identification and management is necessary for improving outcomes and helping patients after discharge. This review will discuss possible PDNV specific risk factors, successful prevention and management of PDNV following ambulatory anesthesia and the principles and pharmacology of these interventions.

Contralateral local anesthetic spread from an outpatient interscalene catheter.

Purpose: Ambulatory continuous infusions have been associated with improved analgesia and few serious complications. This report describes an unusual case of a patient with a continuous interscalene nerve block who developed a contralateral upper extremity sensory block. The complication did not occur until postoperative day two while the patient was at home.

Processed electroencephalogram during donation after cardiac death.

We present a case series of increased bispectral index values during donation after cardiac death (DCD). During the DCD process, a patient was monitored with processed electroencephalogram (EEG), which showed considerable changes traditionally associated with lighter planes of anesthesia immediately after withdrawal of care. Subsequently, to validate the findings of this case, processed EEG was recorded during 2 other cases in which care was withdrawn without the use of hypnotic or anesthetic drugs.

Double-blind comparison of granisetron, promethazine, or a combination of both for the prevention of postoperative nausea and vomiting in females undergoing outpatient laparoscopies.

Purpose: Postoperative nausea and vomiting (PONV) and postdischarge nausea and vomiting (PDNV) are common problems after surgery. Prophylactic combination antiemetic therapy is recommended for patients at high risk for developing PONV and PDNV. Granisetron, a serotonin antagonist, is an effective antiemetic that is devoid of sedative side effect.

Computer-based finite element modeling of insulated Tuohy needles used in regional anesthesia.

Background: Differences in needle design may impact nerve localization. This study evaluates the electrical properties of two insulated Tuohy needles using computational finite element modeling.

Methods: Three-dimensional geometric computer-based models were created representing two 18-gauge, insulated Tuohy needles: (1) with an exposed metal tip and (2) with an insulated tip.

Piezoelectric vibrating needle and catheter for enhancing ultrasound-guided peripheral nerve blocks.

Ultrasound imaging has been used for performing single-injection peripheral nerve blocks and continuous catheters. One limitation with current technology is the inability to confirm the location of the needle or catheter tip. We describe a new needle and catheter design that permits distal tip visualization using color flow Doppler.

Pudendal nerve stimulation evokes reflex bladder contractions in persons with chronic spinal cord injury.

Aims: Although electrical stimulation of the pudendal nerve has been shown to evoke reflex micturition-like bladder contractions in both intact and spinalized cats, there is little evidence to suggest that an analogous excitatory reflex exists in humans, particularly those with spinal cord injury (SCI). We present two cases where electrical activation of pudendal nerve afferents was used to evoke excitatory bladder responses.

Subjects And Methods: A percutaneously placed catheter electrode was used to electrically stimulate the pudendal nerve trunk in two males with SCI.

A computer model of electrical stimulation of peripheral nerves in regional anesthesia.

Background: Nerve stimulation for regional anesthesia can be modeled mathematically. The authors present a mathematical framework to model the underlying electrophysiology, the development of software to implement that framework, and examples of simulation results.

Methods: The mathematical framework includes descriptions of the needle, the resulting potential field, and the active nerve fiber.

Brachial plexus blocks: infusions and other mechanisms to provide prolonged analgesia.

Purpose Of Review: Regional anesthesia has numerous benefits for upper extremity surgery such as improved analgesia, opioid sparing and reduced side effects. However, many of these advantages are lost after block regression. Recently, several strategies such as continuous ambulatory local anesthetic infusions and adjuvants that may potentiate analgesia after a brachial plexus block have been described and investigated.

Combined lumbar-plexus and sciatic-nerve blocks: an analysis of plasma ropivacaine concentrations.

Background And Objectives: Lumbar-plexus and sciatic-nerve blocks are commonly combined for lower-extremity anesthesia using large doses of ropivacaine. Limited information is available about the pharmacokinetics of this practice. We analyzed plasma ropivacaine concentrations after single-injection lumbar-plexus blocks with and without sciatic-nerve blocks.

The effect of age on sciatic nerve block duration.

The physiologic changes that occur with advancing age and their effect on the duration of peripheral nerve blocks have yet to be defined. We prospectively studied the duration of sciatic nerve block using mepivacaine in younger and older patients. Eighty ASA physical status I-III patients, aged 18-35 (n = 40) or 55-80 (n = 40) yr, having outpatient knee arthroscopy with a femoral block and a standardized sciatic nerve block were enrolled; 37 in each group completed the study.

Peripheral nerve block techniques for ambulatory surgery.

Peripheral nerve blocks (PNBs) have an increasingly important role in ambulatory anesthesia and have many characteristics of the ideal outpatient anesthetic: surgical anesthesia, prolonged postoperative analgesia, and facilitated discharge. Critically evaluating the potential benefits and supporting evidence is essential to appropriate technique selection. When PNBs are used for upper extremity procedures, there is consistent opioid sparing and fewer treatment-related side effects when compared with general anesthesia.

Continuous peripheral nerve block for battlefield anesthesia and evacuation.

Peripheral nerve and continuous peripheral nerve block (CPNB) have the potential to be valuable techniques in combat anesthesia. We describe the first successful application of CPNB in the pain management and surgical management of a combat casualty as he was evacuated from the Iraqi battlefield to the United States.

Peripheral nerve blocks and continuous catheter techniques.

Peripheral nerve blocks provide intense, site-specific analgesia and are associated with a lower incidence of side effects when compared with many other modalities of postoperative analgesia. Continuous catheter techniques further prolong these benefits. These advantages can facilitate a prompt recovery and discharge and achieve significant perioperative cost savings.

In situ images of the thoracic paravertebral space.

Background And Objectives: In situ knowledge about the anatomic structures and the path of a needle percutaneously placed into the paravertebral space is an area that continues to be investigated. We describe an endoscopic technique that permits imaging of the contents and boundaries of the thoracic paravertebral space in cadavers.

Technique: A 43-year-old, 157-cm, 45-kg unembalmed female cadaver was placed in the prone position.

Influence of obesity on surgical regional anesthesia in the ambulatory setting: an analysis of 9,038 blocks.

Background: Regional anesthesia is increasing in popularity for ambulatory surgical procedures. Concomitantly, the prevalence of obesity in the United States population is increasing. The objective of the present investigation was to assess the impact of body mass index (BMI) on patient outcomes after ambulatory regional anesthesia.

Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery - an analysis of 9,342 blocks.

Purpose: Regional anesthesia can be the technique of choice for selected ambulatory surgery procedures, but in spite of its benefits, it has an inherent failure rate even in experienced hands. We examine the efficacy and factors associated with failure of ambulatory regional anesthesia techniques.

Methods: This study included 9,342 blocks performed on 7,160 patients at the Duke University Ambulatory Surgery Center.