Anesthesiology

Respiratory depression following general anesthesia, presenting as desaturation and bradypnea, is common during
the early postoperative period. Analysis of anesthesia related closed claims demonstrated that delayed detection
of bradypnea, resulting in desaturation, was a major cause of morbidity and mortality during and following procedures under general anesthesia.

Ventilatory response

Fifty percent of cases of respiratory depression requiring cardiopulmonary resuscitation in hospitals are due to opioid administration. Opioids induce hypercapnia by reducing respiratory rate  and simultaneously decreasing the ventilatory response to both hypercapnia and hypoxemia.

Although providing supplemental oxygen to patients after general anesthesia improves their oxygenation, the opioid-induced bradypnea persists. In a previous study, the majority of postoperative respiratory depression events were judged as preventable with better monitoring and responses.

Although intermittent postoperative monitoring of the patients’ cardio respiratory parameters is performed by nurses, detection of respiratory depression using common clinical signs has been shown to be difficult, suggesting that continuous monitoring of oxygen saturation and respiratory rate can improve patient safety during the postoperative period.

Implementation

Previous studies recommended continuous and centralized monitoring of oxygen saturation and respiratory rate for all
patients in the early phase following general anesthesia. However, the barriers to implementation of continuous and centralized monitoring and adoption of monitoring technology, and lack of staff familiarity with such monitors, are
significant, which makes use of the system in general wards uncommon.

Few reports exist regarding the incidence and risk factors of postoperative respiratory depression in non ICU patients following the use of continuous and centralized monitoring systems. We hypothesized that postoperative desaturation and bradypnea might occur even in non-ICU patients who did not have serious complications and did not undergone major surgery, making it necessary to evaluate them with a continuous and centralized monitoring system.

Centralized monitoring

The Patient SafetyNet system (Masimo Corp., Irvine, CA, USA) with a pulse oximeter and rainbow acoustic respiratory rate monitoring (RRa™) sensor, a non-invasive respiratory rate monitor using an acoustic transducer positioned on the patient’s throat, provides continuous and centralized monitoring of oxygen saturation and respiratory rate. The purpose of the present study was to identify the predictors and incidence of desaturation and bradypnea in non-ICU patients following general anesthesia using the Patient SafetyNet system.
study indicates the incidence and predictors of postoperative desaturation and bradypnea in non-ICU patients
after general anesthesia, determined using a continuous and centralized monitoring system. Postoperative patient
care in general wards represents a high-risk situation . Hence, it is important to clarify risk factors for desaturation and bradypnea, as well as providing context.
The incidence of desaturation and bradypnea in our study was only 12.1% and 5.1%, respectively. The low incidence of desaturation and bradypnea might be due to exclusion of serious cases requiring intensive care, avoidance of long-acting opioids, and reversal of muscle relaxation with sugammadex. Siddiqui. suggested that the most important predictor of desaturation was postoperative care without oxygen supplementation.