Ventilatory frequency during intraoperative mechanical ventilation and postoperative pulmonary complications: a hospital registry study

Abstract

Background: High ventilatory frequencies increase static lung strain and possibly lung stress by shortening expiratory time, increasing intrathoracic pressure, and causing dynamic hyperinflation. We hypothesised that high intraoperative ventilatory frequencies were associated with postoperative respiratory complications. Methods: In this retrospective hospital registry study, we analysed data from adult non-cardiothoracic surgical cases performed under general anaesthesia with mechanical ventilation at a single centre between 2005 and 2017. We assessed the association between intraoperative ventilatory frequency (categorised into four groups) and postoperative respiratory complications, defined as composite of invasive mechanical ventilation within 7 days after surgery or peripheral oxygen desaturation after extubation, using multivariable logistic regression. In a subgroup, we adjusted analyses for arterial blood gas parameters. Results: A total of 102 632 cases were analysed. Intraoperative ventilatory frequencies ranged from a median (interquartile range [IQR]) of 8 (8e9) breaths min À1 (Group 1) to 15 (14e18) breaths min À1 (Group 4). High ventilatory frequencies were associated with higher odds of postoperative respiratory complications (adjusted odds ratio¼1.26; 95% confidence interval, 1.14e1.38; P<0.001), which was confirmed in a subgroup after adjusting for arterial partial pressure of carbon dioxide and the ratio of arterial oxygen partial pressure to fractional inspired oxygen. We identified considerable variability in the use of high ventilatory frequencies attributable to individual provider preference (ranging from 22% to 88%) and temporal change; however, the association with postoperative respiratory complications remained unaffected. Conclusions: High intraoperative ventilatory frequency was associated with increased risk of postoperative respiratory complications, and increased postoperative healthcare utilisation.

A comparison of postoperative respiratory complications associated with the use of desflurane and sevoflurane: a single‐centre cohort study

“…Immediate post‐extubation desaturation is associated with an increase in postoperative pulmonary complications, including increased re‐intubation risk, and may be caused by atelectasis, shunting and other respiratory complications [27]. We have validated these objective markers of respiratory failure in our database and have used this composite outcome in previous studies [17]. Definitions of postoperative respiratory complications previously described [28, 29], include a composite of respiratory infection; respiratory failure; pleural effusion; atelectasis; pneumothorax; bronchospasm; and aspiration pneumonitis, and require accurate temporal clinical coding of ICD diagnoses, which was a limitation within the dataset of the present study.…”

“…Postoperative respiratory failure or the need for post‐extubation respiratory support is an important quality indicator associated with significant morbidity and mortality, and has been shown to be a significant predictor of poor patient outcome, longer stays in hospital and increased costs [16, 25, 26]. Our study explored the primary endpoint of postoperative respiratory complications, which maintains a focus on the immediate post‐extubation and early postoperative phase and are accepted as reliable indicators of risk in this setting [17]. Re‐intubation and the need for invasive ventilation is a significant postoperative event and a reliably documented and accepted patient safety indicator [24].…”

“…The primary outcome was defined beforehand as the occurrence of postoperative respiratory complications. This was in turn defined as a composite of early post-extubation desaturation captured as a peripheral S p O 2 measurement of < 90% within 10 min of tracheal extubation, or the requirement for re-intubation within 7 days postoperatively [16,17]. Secondary outcomes included recovery area length of stay and any delay in discharge from the recovery area for respiratory or sedation-related causes.…”

“…Case‐specific confounders included: surgical specialty; emergency surgery; duration of surgery; work relative value units; and high‐risk surgery, that is, neurosurgery, general, transplant, thoracic, vascular or burns [20]. The following intra‐operative factors were also included in the adjusted analysis [17]: administration of long‐ and short‐acting intravenous opioids (dose expressed as total oral morphine equivalents); use of adjunct analgesic or sedative medications (ketamine, dexmedetomidine, regional anaesthesia); age‐adjusted MAC of nitrous oxide; use of neuromuscular blocking (non‐depolarising and succinylcholine) and reversal agents (neostigmine and sugammadex); total volume of intravenous fluids administered; red blood cell transfusion and vasopressor requirements; duration of intra‐operative hypotension, that is, mean arterial pressure < 55 mmHg; airway device, that is, tracheal tube and/or supraglottic airway; and ventilation parameters, that is, median F I O2, median positive end‐expiratory pressure (PEEP), median peak inspiratory pressure (PIP), weight‐adjusted tidal volume, S p O 2 /F I O 2 ratio and use of a non‐protective ventilation strategy. Non‐protective ventilation strategy was defined as either median PEEP = 0 cmH 2 O or median PEEP > 15 cmH 2 O, median PIP > 35 cmH 2 O; or median tidal volume > 10 ml.kg −1 ) [21].…”

Management of Intraoperative Mechanical Ventilation to Prevent Postoperative Complications after General Anesthesia: A Narrative Review

“…While the primary role of RR could be to keep ETCO 2 in range, we should also consider that RR is directly proportional to the mechanical power and thus is unlikely to be innocent in the genesis of VILI [ 64 ]. Pathophysiologically, a higher respiratory frequency results in higher flow rates to maintain a given VT [ 65 ]. Accordingly, in an experimental model, a reduction of respiratory rate improves indices of lung damage [ 66 ], and recently high ventilatory frequencies (≥14 breath/min) were associated with higher odds of PPCs in 102,632 patients [ 65 ].…”