Noninvasive respiratory support in the perioperative period

Noninvasive respiratory support in the perioperative setting: a narrative review

The application of preoperative noninvasive respiratory support (NRS) has been expanding with increasing recognition of its potential role in this setting as a physiological optimization for patients with a high risk of developing atelectasis and postoperative pulmonary complications (PPC). The increased availability of high-performance anesthesia ventilator machines providing an easy way for NRS support in patients with reduced lung function should not be under-evaluated. This support can reduce hypoxia, restore lung volumes and theoretically reduce atelectasis formation after general anesthesia. Therapeutic purposes should also be considered in the perioperative setting, such as preoperative NRS to optimize treatment of patients' pre-existing diseases, e.g., sleep-disordered breathing. Finally, the recent guidelines for airway management suggest preoperative NRS application before anesthesia induction in difficult airway management to prolong the time needed to secure the airway with an orotracheal tube. This narrative review aims to revise all these aspects and to provide some practical notes to maximize the efficacy of perioperative noninvasive respiratory support.

Perioperative Pulmonary Complications in the Elderly: The Forgotten System

With a rapidly aging population and increasing global surgical volumes, managing the elevated risk of perioperative pulmonary complications has become an expanding focus for quality improvement in health care. In this narrative review, we will analyze the evidence-based literature to provide high-quality and actionable management strategies to better detect, stratify risk, optimize, and manage perioperative pulmonary complications in geriatric populations.

Effects of continuous positive airway pressure administered by a helmet in cats under general anaesthesia

OBJECTIVES

The aim of this study was to evaluate the respiratory effects of non-invasive continuous positive airway pressure (CPAP) administered by a helmet in healthy cats under anaesthesia.

METHODS

Fifteen healthy male cats scheduled for castration were anaesthetised with medetomidine (20 µg/kg), ketamine (10 mg/kg) and buprenorphine (20 µg/kg) intramuscularly. When an adequate level of anaesthesia was achieved, a paediatric helmet was placed on all subjects. The helmet was connected to a Venturi valve supplied with medical air and cats received the following phases of treatments: 0 cmH2O (pre-CPAP), 5 cmH2O (CPAP) and 0 cmH2O (post-CPAP). Each treatment lasted 10 mins. At the end of each phase an arterial blood sample was drawn. The following data were also collected: mean arterial pressure, respiratory rate, heart rate and the anaesthesia level score (0 = awake, 10 = deep anaesthesia). The alveolar to arterial oxygen gradient (P[A-a]O2) and the venous admixture (Fshunt) were also estimated. Data were analysed with two-way ANOVA (P <0.05).

RESULTS

The arterial partial pressure of oxygen was higher (P <0.001) at CPAP (103.2 ± 5.1 mmHg) vs pre-CPAP (77.5 ± 7.4 mmHg) and post-CPAP (84.6 ± 8.1 mmHg). The P(A-a)O2 and the Fshunt were lower (P <0.001) at CPAP (4.4 ± 2.3 mmHg; 7.4 ± 3.1%) vs pre-CPAP (18.9 ± 6.4 mmHg; 22.8 ± 4.6%) and post-CPAP (15.6 ± 7.3 mmHg; 20.9 ± 4.6 %). No other parameters differed between groups.

CONCLUSIONS AND RELEVANCE

Non-invasive CPAP applied by a helmet improves oxygenation in cats under injectable general anaesthesia.

Heated humidified high-flow nasal cannula oxygen after thoracic surgery - A randomized prospective clinical pilot trial

BACKGROUND

Thoracic surgery patients are at high-risk for adverse pulmonary outcomes. Heated humidified high-flow nasal cannula oxygen (HHFNC O₂) may decrease such events. We hypothesized that patients randomized to prophylactic HHFNC O₂ would develop fewer pulmonary complications compared to conventional O₂ therapy.

METHODS AND PATIENTS

Fifty-one patients were randomized to HHFNC O₂ vs. conventional O₂. The primary outcome was a composite of postoperative pulmonary complications. Secondary outcomes included oxygenation and length of stay. Continuous variables were compared with t-test or Mann-Whitney-U test, categorical variables with Fisher's Exact test.

RESULTS

There were no differences in postoperative pulmonary complications based on intention to treat [two in HHFNC O₂ (n=25), two in control (n=26), p=0.680], and after exclusion of patients who discontinued HHFNC O₂ early [one in HHFNC O₂ (n=18), two in control (n=26), p=0.638]. Discomfort from HHFNC O₂ occurred in 11/25 (44%); 7/25 (28%) discontinued treatment.

CONCLUSIONS

Pulmonary complications were rare after thoracic surgery. Although HHFNC O₂ did not convey significant benefits, these results need to be interpreted with caution, as our study was likely underpowered to detect a reduction in pulmonary complications. High rates of patient-reported discomfort with HHFNC O₂ need to be considered in clinical practice and future trials.

[Non-invasive mechanical ventilation in postoperative patients. A clinical review]

Non-invasive ventilation (NIV) is a method of ventilatory support that is increasing in importance day by day in the management of postoperative respiratory failure. Its role in the prevention and treatment of atelectasis is particularly important in the in the period after thoracic and abdominal surgeries. Similarly, in the transplanted patient, NIV can shorten the time of invasive mechanical ventilation, reducing the risk of infectious complications in these high-risk patients. It has been performed A systematic review of the literature has been performed, including examining the technical, clinical experiences and recommendations concerning the application of NIV in the postoperative period.