Accelerometry May be Superior to EMG for Early Evaluation of Vocal Cord Function After Nerve Injury in a Pig Model.

Objective: Vocal cord (VC) movement has been demonstrated by the use of accelerometry (ACC) to decrease in parallel with the electromyographic amplitude (EMG) during ongoing traction injury to the recurrent laryngeal nerve (RLN). When RLN function recovers, discrepancies between EMG and VC movement have been reported in clinical and experimental studies. The present study was conducted to clarify the actual relationship between EMG and VC movement measured by ACC during nerve recovery.

An experimental study on intraoperative recovery of recurrent laryngeal nerve function.

Objective: If bilateral thyroid surgery is planned and staged thyroidectomy considered in case of loss of neuromonitoring signal (LOS), a waiting time of 20 minutes is suggested for evaluation of early nerve recovery. This recommendation is based on clinical observations and has not been thoroughly validated experimentally.

Methods: Sixteen pigs were randomly studied, and electromyogram (EMG) was continuously recorded during traction injury until an amplitude decrease of 70% from baseline (BL) (16 nerves) or LOS (16 nerves), and further during 40-minute recovery time.

Vocal cord function during recurrent laryngeal nerve injury assessed by accelerometry and EMG.

Objective: Gradual impairment of nerve conduction is expected to be tightly associated with simultaneous gradual loss of vocal cord contractility, related to the fact that injured axons are connected to a defined number of muscle cells. In clinical studies, there is a time gap between observed adverse electromyographic (EMG) changes and examination of vocal cord function. This study evaluates the impact of intraoperative EMG changes on synchronous vocal cord contractility by simultaneous use of continuous intraoperative neuromonitoring (C-IONM) and accelerometry for registration of actual vocal cord function at a given change of EMG amplitude.

Hypothermia outcome prediction after extracorporeal life support for hypothermic cardiac arrest patients: The HOPE score.

Aims: Currently, the decision to initiate extracorporeal life support for patients who suffer cardiac arrest due to accidental hypothermia is essentially based on serum potassium level. Our goal was to build a prediction score in order to determine the probability of survival following rewarming of hypothermic arrested patients based on several covariates available at admission.

Methods: We included consecutive hypothermic arrested patients who underwent rewarming with extracorporeal life support.

Is the use of hydroxyethyl starch as priming solution during cardiac surgery advisable? A randomized, single-center trial.

Introduction: The use of cardiopulmonary bypass (CPB) leads to increased fluid filtration and edema. The use of artificial colloids to counteract fluid extravasation during cardiac surgery is controversial. Beneficial effects on global fluid loading, leading to better cardiac performance and hemodynamics, have been claimed.

Injury mechanisms and electromyographic changes after injury of the recurrent laryngeal nerve: Experiments in a porcine model.

Background: Recurrent laryngeal nerve (RLN) injury during surgery may reveal differences in electromyographic (EMG) changes after sustained compression or traction.

Methods: In 20 pigs with the NIM-FLEX EMG-endotracheal tube, EMG was recorded at baseline, during sustained RLN compression, or traction until 70% amplitude decrease and during 30 minutes of recovery.

Results: Seventy percent amplitude decrease from baseline was reached after 110 ± 98 seconds (compression group) and 2034 ± 2108 seconds (traction group).

Microvascular fluid exchange during CPB with deep hypothermia circulatory arrest or low flow.

Objective: Use of deep hypothermic low-flow (DHLF) cardiopulmonary bypass (CPB) has been associated with higher fluid loading than the use of deep hypothermia circulatory arrest (DHCA). We evaluated whether these perfusion strategies influenced fluid extravasation rates and edema generation differently per-operatively.

Materials And Methods: Twelve anesthetized pigs, randomly allocated to DHLF (n = 6) or DHCA (n = 6), underwent 2.

Outcome After Rewarming From Accidental Hypothermia by Use of Extracorporeal Circulation.

Background: Accidental hypothermia with arrested circulation remains a condition associated with high mortality. In our institution, extracorporeal circulation (ECC) rewarming has been the cornerstone in treating such patients since 1987. We here explore characteristics and outcomes of this treatment, to identify significant merits and challenges from 3 decades of experience in ECC rewarming.

Does Roller Pump-Induced Pulsatile CPB Perfusion Affect Microvascular Fluid Shifts and Tissue Perfusion?

Background: Pulsatile versus nonpulsatile cardiopulmonary bypass (CPB) perfusion remains debated. Beneficial effects on tissue perfusion, inflammation, and microvascular fluid exchange have been linked to pulsatile perfusion by some investigators and denied by others. This study evaluated fluid extravasation and tissue perfusion during nonpulsatile or pulsatile roller pump-induced CPB perfusion.

EMG changes during continuous intraoperative neuromonitoring with sustained recurrent laryngeal nerve traction in a porcine model.

Purpose: Traction is the most common cause of injury to the recurrent laryngeal nerve (RLN) in endocrine neck surgery. The purpose of this study was to evaluate specific alterations to the electromyogram (EMG) and verify safe alarm limits in a porcine model of sustained traction of the RLN using continuous intraoperative neuromonitoring (C-IONM).

Methods: Sixteen Norwegian Landrace pigs were anesthetized and intubated with a tracheal tube with a stick-on laryngeal electrode.

Fluid filtration and vascular compliance during cardiopulmonary bypass: effects of two volatile anesthetics.

Background: As intraoperative fluid accumulation may negatively impact post-operative organ function, strategies minimizing edema generation should be sought for. During general anesthesia, isoflurane in contrast to sevoflurane has been associated with increased fluid extravasation and edema generation. In this study, we tested sevoflurane against isoflurane with focus on vascular compliance and fluid shifts in an experimental cardiopulmonary bypass (CPB) model.

Does insulin impact cold-induced fluid- and protein-extravasation?

Background: Insulin has been shown to stabilize the endothelial barrier via inactivation of the endothelial contractile machinery and enhancement of cell-cell adhesions. Here we explored if insulin by its endothelial-stabilizing and anti-inflammatory properties could influence the increase of fluid- and protein-extravasation during hypothermia.

Methods: Two groups of animals (n=10, each) were cooled to 28°C, with insulin-infusion (I-group) or without (C-group), in a randomly controlled study.

Intraaortic counterpulsation during cardiopulmonary bypass impairs distal organ perfusion.

Background: Recent studies have focused on the use of fixed-rate intraaortic balloon pumping (IABP) during cardiopulmonary bypass (CPB) to achieve pulsatile flow. Because application of an IABP catheter may represent a functional obstruction within the descending aorta, we explored the effect of IABP-pulsed CPB-perfusion with special attention to perfusion above and below the IABP balloon.

Methods: Sixteen animals received an IABP catheter that remained turned off position (NP group, n = 8) or was switched to an automatic mode of 80 beats/min during CPB (PP group, n = 8).

Acute elevation of intra-abdominal pressure contributes to extravascular shift of fluid and proteins in an experimental porcine model.

Background: Intra-abdominal hypertension and abdominal compartment syndrome contribute significantly to increased morbidity and mortality in critically ill patients. This study describes pathophysiologic effects of the acutely elevated intra-abdominal pressure on microvascular fluid exchange and microcirculation. The resulting changes could contribute to development of organ dysfunction or failure.

Portal cytokine response and metabolic markers in the early stages of abdominal sepsis in pigs.

Background: The portal vein could play a major role in disseminating the local inflammation of acute bacterial peritonitis since it is responsible for the venous drainage of the gastrointestinal tract. We hypothesized that after peritoneal exposure to Escherichia coli, a gradient between the portal and systemic levels of cytokines would be expected.

Methods: Acute peritonitis was induced by depositing 200 ml of broth with live E.

Microvascular fluid exchange during pulsatile cardiopulmonary bypass perfusion with the combined use of a nonpulsatile pump and intra-aortic balloon pump.

Objective: To evaluate how pulsed versus nonpulsed cardiopulmonary bypass influences microvascular fluid exchange in an experimental setup combining a nonpulsatile perfusion pump and an intra-aortic balloon pump.

Methods: A total of 16 pigs were randomized to pulsatile cardiopulmonary bypass perfusion with an intra-aortic balloon pump switched to an automatic 80 beats/min mode after the start of cardiopulmonary bypass (pulsatile perfusion [PP] group, n = 8) or to nonpulsatile cardiopulmonary bypass with the pump switched to the off position (nonpulsatile [NP] group, n = 8). Normothermic cardiopulmonary bypass was initiated after 60 minutes of stabilization and continued for 3 hours.

Isoflurane in contrast to propofol promotes fluid extravasation during cardiopulmonary bypass in pigs.

Background: A highly positive intraoperative fluid balance should be prevented as it negatively impacts patient outcome. Analysis of volume-kinetics has identified an increase in interstitial fluid volume after crystalloid fluid loading during isoflurane anesthesia. Isoflurane has also been associated with postoperative hypoxemia and may be associated with an increase in alveolar epithelial permeability, edema formation, and hindered oxygen exchange.

Does β2-adrenergic stimulation attenuate fluid extravasation during hypothermic cardiopulmonary bypass? An experimental study in pigs.

Objectives: Hypothermic cardiopulmonary bypass (CPB) is associated with increased fluid filtration, edema formation and, occasionally, organ dysfunction. Cold-induced reduction in endothelial barrier function may play a role. β(2)-adrenergic activation elevates cellular cyclic adenosine monophosphate (cAMP) which maintains endothelial barrier properties.

Isolation of interstitial fluid in skin during volume expansion: evaluation of a method in pigs.

The ability to isolate interstitial fluid (IF) from skin would make it possible to study the microcirculation and proteins in this environment both during normal and pathophysiological conditions. Traditional IF sampling using implanted wicks suffer from low volumes with risk of contamination by local inflammatory, intracellular, and vascular proteins. To sample larger volumes of true IF, a recently described tissue centrifugation method was compared with dry and wet wicks from porcine skin under normal conditions and following volume expansion.

Infusion of hypertonic saline/starch during cardiopulmonary bypass reduces fluid overload and may impact cardiac function.

Objective: Peri-operative fluid accumulation resulting in myocardial and pulmonary tissue edema is one possible mechanism behind post-operative cardiopulmonary dysfunction. This study aimed to confirm an improvement of cardiopulmonary function by reducing fluid loading during an open-heart surgery.

Materials And Methods: Forty-nine elective CABG patients were randomized to an intraoperative infusion of hypertonic saline/hydroxyethyl starch (HSH group) or Ringer's solution (CT group).