Transcutaneous Electrical Stimulation for Apnea Detected by Capnography

After surgery, patients often recover in a special area called the Post Anesthesia Care Unit (PACU). Patients may receive pain medications either during the surgery or afterward in the PACU. While these medications are important for controlling pain, some of them can slow down breathing.

To ensure patients' breathing remains safe, the nurses in the PACU monitor respiratory rate (how many breaths a patient takes per minute) and oxygen levels using standard monitoring equipment. This is the usual way they check for breathing concerns. If these monitors show that a patient's breathing has slowed down too much, nurses may wake the patient up or stimulate them using their voice or gentle physical touch to encourage deeper breaths.

What is this study about? This research is testing a new approach that uses an additional monitor called capnography. Capnography helps detect slowing or stopping of breathing by measuring the carbon dioxide (CO2) exhaled by patients. If the monitor shows slowed or stopped breathing (called apnea, lasting at least 10 seconds), this study will test using a technology called transcutaneous electrical stimulation (TES) to encourage normal breathing.

How does TES work? TES provides a slight, annoying sensation on the patient's skin-enough to wake them up without causing pain. This has been used in other studies to safely restore breathing after surgery. In this study, the researchers are testing whether a new automated device can deliver TES when the capnography monitor detects breathing issues. The goal is to test the feasibility (can this system work in the PACU?) and acceptability (how do patients feel about this approach?) of this technology.

Who can join this study? Adults aged 18 or older who received general anesthesia and medications (opioids) for pain control during or after surgery are eligible. Patients recovering from surgery in the PACU at Toronto General Hospital may be invited to participate.

Why is this study important? The study aims to reduce the risk of opioid-related breathing problems after surgery, making recovery safer and more comfortable for patients.


Eligibility Criteria:
Inclusion Criteria:

* Males and females at least 18 years old
* Adults undergoing an elective (General, Plastics, Urology, Gynecologic Oncology, Vascular, Otolaryngology, Transplant) surgery with general anesthesia who are recovering in the PACU
* American Society of Anesthesiologists (ASA) grade I-IV
* Scheduled to be seen at the Pre-Admission Clinic or Surgery Inpatient Unit
* Able to complete questionnaires with or without assistance
* Able to understand the study protocol, its requirements, risks, and discomforts
* Able to provide written informed consent

Exclusion Criteria:

* A) Preoperative exclusion criteria:

  * American Society of Anesthesiologists (ASA) grade V-VI
  * Urgent or emergent surgical procedures that there is insufficient time prior to anticipated commencement of the procedure for participation in the study
  * Patients with implantable medical electronic devices (eg, pacemaker, implantable cardioverter defibrillator, catheter, and so on.)
  * Patients with febrile illnesses or acute infectious diseases
  * Pregnancy
  * Epilepsy.
* B) Postoperative exclusion criteria:

  * Surgery that would preclude the use of a nasal cannula or face mask used for capnography monitoring (e.g., facial reconstruction)
  * Postoperative mental status precludes application of study equipment, including a nasal cannula/face mask and/or the stimulation pads (e.g., delirium or agitation during recovering from anesthesia, repeated removal of cannula)
  * Postoperative admission to the ICU or any site other than the PACU
  * Need for postoperative assisted ventilation via an endotracheal tube or tracheostomy
  * An abnormal respiratory tract identified during or immediately after surgery can lead to severe respiratory obstruction
  * Patients with cardiac arrhythmia (history of atrial fibrillation or bundle branch block)
  * Skin conditions such as open sores preventing proper application of electrodes
  * Presence of metal implants in both arms
  * Lack of access to upper extremities following surgery for application of the stimulation pads