AANA Journal Course: Update for Nurse Anesthetists-Optimizing Mechanical Ventilation During General Anesthesia.

Optimal mechanical ventilatory support is a vital component of intraoperative anesthesia care, lung protection, and minimizing postoperative pulmonary sequela. Although concepts surrounding ventilation can be multifaceted and ambiguous, a pragmatic approach coupled with contemporary evidence and skilled assessments will facilitate ideal intraoperative management. Effective mechanical ventilation is dependent on obtaining the best pulmonary mechanics, including compliance, resistance, and gas exchange. Optimally titrated positive end-expiratory pressure is the foundation for ideal pulmonary mechanics, preventing ventilator-induced lung injury, and minimizing postoperative pulmonary complications. A knowledgeable application of pressure support ventilation can offer additional advantages during general anesthesia and emergence, providing synchronized ventilation and augmenting the patient's own respiratory efforts. These concepts, coupled with clinical expertise, will offer insight into the methods, tools, and techniques available to modern anesthetists.

Increase in intra-abdominal pressure during airway suctioning-induced cough after a successful spontaneous breathing trial is associated with extubation outcome.

BACKGROUND: A patient's ability to clear secretions and protect the airway with an effective cough is an important part of the pre-extubation evaluation. An increase in intra-abdominal pressure (IAP) is important in generating the flow rate necessary for a cough. This study investigated whether an increase from baseline in IAP during a coughing episode induced by routine pre-extubation airway suctioning is associated with extubation outcome after a successful spontaneous breathing trial (SBT). METHODS: Three hundred thirty-five (335) mechanically ventilated patients who passed an SBT were enrolled. Baseline IAP and peak IAP during successive suctioning-induced coughs were measured with a fluid column connected to a Foley catheter. RESULTS: Extubation was unsuccessful in 24 patients (7.2%). Unsuccessful extubation was 3.40 times as likely for patients with a delta IAP (ΔIAP) of ≤ 30 cm H2O than for those with a ΔIAP > 30 cm H2O, after adjusting for APACHE II score (95% CI, 1.39-8.26; p = .007). CONCLUSION: ΔIAP during a coughing episode induced by routine pre-extubation airway suctioning is significantly associated with extubation outcome in patients with a successful SBT. Trial registration UMIN-CTR Clinical Trial, UMIN000017762. Registered 1 June 2015.

Clinical management of pressure control ventilation: An algorithmic method of patient ventilatory management to address "forgotten but important variables".

Pressure controlled ventilation is a common mode of ventilation used to manage both adult and pediatric populations. However, there is very little evidence that distinguishes the efficacy of pressure controlled ventilation over that of volume controlled ventilation in the adult population. This gap in the literature may be due to the absence of a consistent and systematic algorithm for managing pressure controlled ventilation. This article provides a brief overview of the applications of both pressure controlled ventilation and volume controlled ventilation and proposes an algorithmic approach to the management of patients receiving pressure controlled ventilation. This algorithmic approach highlights the need for clinicians to have a comprehensive conceptual understanding of mechanical ventilation, pulmonary physiology, and interpretation of ventilator graphics in order to best care for patients receiving pressure controlled ventilation. The objective of identifying a systematic approach to managing pressure controlled ventilation is to provide a more generalizable and equitable approach to management of the ICU patient. Ideally, a consistent approach to managing pressure controlled ventilation in the adult population will glean more reliable information regarding actual patient outcomes, as well as the efficacy of pressure controlled ventilation when compared to volume controlled ventilation.

Impact of physician education and availability of parameters regarding esophageal pressure and transpulmonary pressure on clinical decisions involving ventilator management.

PURPOSE: This study investigated the effects of physician education and the availability of Peso and PL data on physicians' decisions regarding ventilator management during specific simulated clinical conditions. MATERIALS AND METHODS: The study was a prospective, before-after study using a case scenario-based questionnaire and a case simulator device comprising an Avea ventilator and an artificial lung and esophagus, which was connected to a Series 1101 Electronic Breathing Simulator. The 99 physicians participating in the study were provided with five simulated cases with on-time ventilator graphics without Peso and PL and completed a questionnaire on decisions they would make regarding ventilator management of the cases. Then, after receiving instruction on Peso and PL, they were given the same cases along with ventilator graphics that included Peso and PL. RESULTS: After receiving instruction and data on Peso and PL, statistically significant numbers of physicians changed their answers regarding ventilator management decisions in all five cases. CONCLUSIONS: Providing education and data for Peso and PL had a significant effect on physician decisions regarding ventilator management in simulated cases. The use of case scenario-based education with simulator devices for physicians may hasten worldwide understanding and clinical application of Peso and PL.

Limiting volume with modern ventilators.

BACKGROUND: The acute respiratory distress syndrome (ARDS) network low tidal-volume study comparing tidal volumes of 12 ml/kg versus 6 ml/kg was published in 2000. The study was stopped early as data revealed a 22% relative reduction in mortality rate when using 6 ml/kg tidal volume. The current generation of critical care ventilators allows the tidal volume to be set during volume-targeted, assist/control (volume A/C); however, some ventilators include options that may prevent the tidal volume from being controlled. The purpose of this bench study was to evaluate the delivered tidal volume, when these options are active, in a spontaneously breathing lung model using an electronic breathing simulator. METHODS: Four ventilators were evaluated: CareFusion AVEA (AVEA), Dräger Evita® XL (Evita XL), Covidien Puritan Bennett® 840(TM) (PB 840), and Maquet SERVO-i (SERVO-i). Each ventilator was connected to the Hans Rudolph Electronic Breathing Simulator at an amplitude of 0 cm H2O and then 10 cm H2O. All four ventilators were set to deliver volume A/C, tidal volume 400 ml, respiratory rate 20 bpm, positive end-expiratory pressure 5 cm H2O, peak flowrate 60 L/min. The displayed tidal volume was recorded for each ventilator at the above settings with additional options OFF and then ON. RESULTS: The AVEA has two options in volume A/C: demand breaths and V-sync. When activated, these options allow the patient to exceed the set tidal volume. When using the Evita XL, the option AutoFlow can be turned ON or OFF, and when this option is ON, the tidal volume may vary. The PB 840 does not have any additional options that affect volume delivery, and it maintains the set tidal volume regardless of patient effort. The SERVO-i's demand valve allows additional flow if the patient's inspiratory flowrate exceeds the set flowrate, increasing the delivered tidal volume; this option can be turned OFF with the latest software upgrade. CONCLUSIONS: Modern ventilators have an increasing number of optional settings. These settings may increase the delivered tidal volume and disrupt a low tidal-volume strategy. Recognizing how each setting within a mode affects the type of breath delivered is critical when caring for ventilator-dependent patients.

Implementation of do not attempt resuscitate orders in a Japanese nursing home.

OBJECTIVE: To investigate whether do not attempt resuscitation (DNAR) orders can be implemented in a standard nursing home in Japan, where routine DNAR orders are not yet common in many facilities including hospitals. METHOD: Ninety-eight residents in a 100-bed nursing home were evaluated. All of the eligible residents and/or their family members were asked whether they wanted to receive resuscitation, including mechanical ventilation. RESULT: The residents were 54 to 101 years of age (mean 83.3), with 27 males and 71 females. After administering the questionnaire, 92 (94%) patients did not want resuscitation and mechanical ventilation. CONCLUSION: In a nursing home, it was possible to obtain advance directives by which most residents/families rejected resuscitation and mechanical ventilation. This could avoid unnecessary and undesirable resuscitation procedures.