-
Anesthesiology Jan 2022Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface... (Review)
Review
Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.
Topics: Animals; Diaphragm; Humans; Intraoperative Complications; Lung; Perioperative Care; Pulmonary Atelectasis; Respiration, Artificial
PubMed: 34499087
DOI: 10.1097/ALN.0000000000003943 -
Anesthesiology Jan 2022The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics... (Review)
Review
The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient's safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.
Topics: Humans; Intraoperative Complications; Lung; Manometry; Obesity; Perioperative Care; Positive-Pressure Respiration; Pulmonary Atelectasis; Respiration, Artificial; Risk Factors; Smoking
PubMed: 34710217
DOI: 10.1097/ALN.0000000000004009 -
Anesthesiology Apr 2005Atelectasis occurs in the dependent parts of the lungs of most patients who are anesthetized. Development of atelectasis is associated with decreased lung compliance,... (Review)
Review
Atelectasis occurs in the dependent parts of the lungs of most patients who are anesthetized. Development of atelectasis is associated with decreased lung compliance, impairment of oxygenation, increased pulmonary vascular resistance, and development of lung injury. The adverse effects of atelectasis persist into the postoperative period and can impact patient recovery. This review article focuses on the causes, nature, and diagnosis of atelectasis. The authors discuss the effects and implications of atelectasis in the perioperative period and illustrate how preventive measures may impact outcome. In addition, they examine the impact of atelectasis and its prevention in acute lung injury.
Topics: Aging; Anesthesia; Humans; Intraoperative Complications; Pulmonary Atelectasis; Respiratory Function Tests; Vascular Resistance
PubMed: 15791115
DOI: 10.1097/00000542-200504000-00021 -
Respiratory Medicine Oct 2021Setting the proper level of positive end-expiratory pressure (PEEP) is a cornerstone of lung protective ventilation. PEEP keeps the alveoli open at the end of... (Review)
Review
Setting the proper level of positive end-expiratory pressure (PEEP) is a cornerstone of lung protective ventilation. PEEP keeps the alveoli open at the end of expiration, thus reducing atelectrauma and shunt. However, excessive PEEP may contribute to alveolar overdistension. Electrical impedance tomography (EIT) is a non-invasive bedside tool that monitors in real-time ventilation distribution. Aim of this narrative review is summarizing the techniques for EIT-guided PEEP titration, while providing useful insights to enhance comprehension on advantages and limits of EIT for current and future users. EIT detects thoracic impedance to alternating electrical currents between pairs of electrodes and, through the analysis of its temporal and spatial variation, reconstructs a two-dimensional slice image of the lung depicting regional variation of ventilation and perfusion. Several EIT-based methods have been proposed for PEEP titration. The first described technique estimates the variations of regional lung compliance during a decremental PEEP trial, after lung recruitment. The optimal PEEP value is represented by the best compromise between lung collapse and overdistension. Later on, a second technique assessing alveolar recruitment by variation of the end-expiratory lung impedance was validated. Finally, the global inhomogeneity index and the regional ventilation delay, two EIT-derived parameters, showed promising results selecting the optimal PEEP value as the one that presents the lowest global inhomogeneity index or the lowest regional ventilation delay. In conclusion EIT represents a promising technique to individualize PEEP in mechanically ventilated patients. Whether EIT is the best technique for this purpose and the overall influence of personalizing PEEP on clinical outcome remains to be determined.
Topics: Electric Impedance; Humans; Lung; Monitoring, Physiologic; Point-of-Care Testing; Positive-Pressure Respiration; Pulmonary Atelectasis; Respiratory Distress Syndrome; Tomography
PubMed: 34352563
DOI: 10.1016/j.rmed.2021.106555 -
JAMA Surgery Jul 2019Incentive spirometers (ISs) were developed to reduce atelectasis and are in widespread clinical use. However, without IS use adherence data, the effectiveness of IS... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Incentive spirometers (ISs) were developed to reduce atelectasis and are in widespread clinical use. However, without IS use adherence data, the effectiveness of IS cannot be determined.
OBJECTIVE
To evaluate the effect of a use-tracking IS reminder on patient adherence and clinical outcomes following coronary artery bypass grafting (CABG) surgery.
DESIGN, SETTING, AND PARTICIPANTS
This randomized clinical trial was conducted from June 5, 2017, to December 29, 2017, at a tertiary referral teaching hospital and included 212 patients who underwent CABG, of whom 160 participants were randomized (intent to treat), with 145 completing the study per protocol. Participants were stratified by surgical urgency (elective vs nonelective) and sex (men vs women).
INTERVENTIONS
A use-tracking, IS add-on device (SpiroTimer) with an integrated use reminder bell recorded and timestamped participants' inspiratory breaths. Patients were randomized by hourly reminder "bell on" (experimental group) or "bell off" (control group).
MAIN OUTCOMES AND MEASURES
Incentive spirometer use was recorded for the entire postoperative stay and compared between groups. Radiographic atelectasis severity (score, 0-10) was the primary clinical outcome. Secondary respiratory and nonrespiratory outcomes were also evaluated.
RESULTS
A total of 145 per-protocol participants (112 men [77%]; mean age, 69 years [95% CI, 67-70]; 90 [62%] undergoing a nonelective procedure) were evaluated, with 74 (51.0%) in the bell off group and 71 (49.0%) in the bell on group. The baseline medical and motivation-to-recover characteristics of the 2 groups were similar. The mean number of daily inspiratory breaths was greater in bell on (35; 95% CI, 29-43 vs 17; 95% CI, 13-23; P < .001). The percentage of recorded hours with an inspiratory breath event was greater in bell on (58%; 95% CI, 51-65 vs 28%; 95% CI, 23-32; P < .001). Despite no differences in the first postoperative chest radiograph mean atelectasis severity scores (2.3; 95% CI, 2.0-2.6 vs 2.4; 95% CI, 2.2-2.7; P = .48), the mean atelectasis severity scores for the final chest radiographs conducted before discharge were significantly lower for bell on than bell off group (1.5; 95% CI, 1.3-1.8 vs 1.8; 95% CI, 1.6-2.1; P = .04). Of those with early postoperative fevers, fever duration was shorter for bell on (3.2 hours; 95% CI, 2.3-4.6 vs 5.2 hours; 95% CI, 3.9-7.0; P = .04). Having the bell turned on reduced noninvasive positive pressure ventilation use rates (37.2%; 95% CI, 24.1%-52.5% vs 19.2%; 95% CI, 10.2%-33.0%; P = .03) for participants undergoing nonelective procedures. Bell on reduced the median postoperative length of stay (7 days; 95% CI, 6-9 vs 6 days; 95% CI, 6-7; P = .048) and the intensive care unit length of stay for patients undergoing nonelective procedures (4 days; 95% CI, 3-5 vs 3 days; 95% CI, 3-4; P = .02). At 6 months, the bell off mortality rate was higher than bell on (9% vs 0%, P = .048) for participants undergoing nonelective procedures.
CONCLUSIONS AND RELEVANCE
The incentive spirometer reminder improved patient adherence, atelectasis severity, early postoperative fever duration, noninvasive positive pressure ventilation use, ICU and length of stay, and 6-month mortality in certain patients. With the reminder, IS appears to be clinically effective when used appropriately.
TRIAL REGISTRATION
ClinicalTrials.gov identifier: NCT02952027.
Topics: Aged; Coronary Artery Bypass; Coronary Artery Disease; Female; Follow-Up Studies; Humans; Incidence; Intensive Care Units; Male; Patient Compliance; Postoperative Complications; Pulmonary Atelectasis; Retrospective Studies; Spirometry; Survival Rate; United States
PubMed: 30969332
DOI: 10.1001/jamasurg.2019.0520 -
Anesthesiology Dec 2018WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications... (Randomized Controlled Trial)
Randomized Controlled Trial
WHAT WE ALREADY KNOW ABOUT THIS TOPIC
WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Intraoperative lung-protective ventilation has been recommended to reduce postoperative pulmonary complications after abdominal surgery. Although the protective role of a more physiologic tidal volume has been established, the added protection afforded by positive end-expiratory pressure (PEEP) remains uncertain. The authors hypothesized that a low fixed PEEP might not fit all patients and that an individually titrated PEEP during anesthesia might improve lung function during and after surgery.
METHODS
Forty patients were studied in the operating room (20 laparoscopic and 20 open-abdominal). They underwent elective abdominal surgery and were randomized to institutional PEEP (4 cm H2O) or electrical impedance tomography-guided PEEP (applied after recruitment maneuvers and targeted at minimizing lung collapse and hyperdistension, simultaneously). Patients were extubated without changing selected PEEP or fractional inspired oxygen tension while under anesthesia and submitted to chest computed tomography after extubation. Our primary goal was to individually identify the electrical impedance tomography-guided PEEP value producing the best compromise of lung collapse and hyperdistention.
RESULTS
Electrical impedance tomography-guided PEEP varied markedly across individuals (median, 12 cm H2O; range, 6 to 16 cm H2O; 95% CI, 10-14). Compared with PEEP of 4 cm H2O, patients randomized to the electrical impedance tomography-guided strategy had less postoperative atelectasis (6.2 ± 4.1 vs. 10.8 ± 7.1% of lung tissue mass; P = 0.017) and lower intraoperative driving pressures (mean values during surgery of 8.0 ± 1.7 vs. 11.6 ± 3.8 cm H2O; P < 0.001). The electrical impedance tomography-guided PEEP arm had higher intraoperative oxygenation (435 ± 62 vs. 266 ± 76 mmHg for laparoscopic group; P < 0.001), while presenting equivalent hemodynamics (mean arterial pressure during surgery of 80 ± 14 vs. 78 ± 15 mmHg; P = 0.821).
CONCLUSIONS
PEEP requirements vary widely among patients receiving protective tidal volumes during anesthesia for abdominal surgery. Individualized PEEP settings could reduce postoperative atelectasis (measured by computed tomography) while improving intraoperative oxygenation and driving pressures, causing minimum side effects.
Topics: Abdomen; Adult; Aged; Anesthesia, Intravenous; Elective Surgical Procedures; Female; Humans; Intraoperative Care; Laparoscopy; Length of Stay; Male; Middle Aged; Oxygen Consumption; Positive-Pressure Respiration; Postoperative Complications; Precision Medicine; Pulmonary Atelectasis; Respiration, Artificial; Tidal Volume; Tomography
PubMed: 30260897
DOI: 10.1097/ALN.0000000000002435 -
Journal of Cardiothoracic Surgery Aug 2021Postoperative pulmonary complications (PPCs) often occur after cardiac operations and are a leading cause of morbidity, inhibit oxygenation, and increase hospital length... (Randomized Controlled Trial)
Randomized Controlled Trial
Preoperative incentive spirometry for preventing postoperative pulmonary complications in patients undergoing coronary artery bypass graft surgery: a prospective, randomized controlled trial.
BACKGROUND
Postoperative pulmonary complications (PPCs) often occur after cardiac operations and are a leading cause of morbidity, inhibit oxygenation, and increase hospital length of stay and mortality. Although clinical evidence for PPCs prevention is often unclear and crucial, measures occur to reduce PPCs. One device usually used for this reason is incentive spirometry (IS). The aim of the study is to evaluate the effect of preoperative incentive spirometry to prevent postoperative pulmonary complications, improve postoperative oxygenation, and decrease hospital stay following coronary artery bypass graft (CABG) surgery patients.
METHODS
This was a clinical randomized prospective study. A total of 80 patients were selected as candidates for CABG at An-Najah National University Hospital, Nablus-Palestine. Patients had been randomly assigned into two groups: incentive spirometry group (IS), SI performed before surgery (study group) and control group, preoperative spirometry was not performed. The 40 patients in each group received the same protocol of anesthesia and ventilation in the operating room.
RESULT
The study findings showed a significant difference between the IS and control groups in the incidence of postoperative atelectasis. There were 8 patients (20.0%) in IS group and 17 patients (42.5%) in the control group (p = 0.03). Mechanical ventilation duration was significantly less in IS group. The median was four hours versus six hours in the control group (p < 0.001). Hospital length of stay was significantly less in IS group, and the median was six days versus seven days in the control group (p < 0.001). The median of the amount of arterial blood oxygen and oxygen saturation was significantly improved in the IS group (p < 0.005).
CONCLUSION
Preoperative incentive spirometry for two days along with the exercise of deep breathing, encouraged coughing, and early ambulation following CABG are in connection with prevention and decreased incidence of atelectasis, hospital stay, mechanical ventilation duration and improved postoperative oxygenation with better pain control. A difference that can be considered both significant and clinically relevant. Trial registration Thai Clinical Trials Registry: TCTR20201020005. Registered 17 October 2020-retrospectively registered.
Topics: Coronary Artery Bypass; Humans; Length of Stay; Motivation; Postoperative Complications; Prospective Studies; Pulmonary Atelectasis; Spirometry
PubMed: 34429138
DOI: 10.1186/s13019-021-01628-2 -
Anesthesiology Sep 2023Individualized positive end-expiratory pressure (PEEP) guided by dynamic compliance improves oxygenation and reduces postoperative atelectasis in nonobese patients. The... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Individualized positive end-expiratory pressure (PEEP) guided by dynamic compliance improves oxygenation and reduces postoperative atelectasis in nonobese patients. The authors hypothesized that dynamic compliance-guided PEEP could also reduce postoperative atelectasis in patients undergoing bariatric surgery.
METHODS
Patients scheduled to undergo laparoscopic bariatric surgery were eligible. Dynamic compliance-guided PEEP titration was conducted in all patients using a downward approach. A recruitment maneuver (PEEP from 10 to 25 cm H2O at 5-cm H2O step every 30 s, with 15-cm H2O driving pressure) was conducted both before and after the titration. Patients were then randomized (1:1) to undergo surgery under dynamic compliance-guided PEEP (PEEP with highest dynamic compliance plus 2 cm H2O) or PEEP of 8 cm H2O. The primary outcome was postoperative atelectasis, as assessed with computed tomography at 60 to 90 min after extubation, and expressed as percentage to total lung tissue volume. Secondary outcomes included Pao2/inspiratory oxygen fraction (Fio2) and postoperative pulmonary complications.
RESULTS
Forty patients (mean ± SD; 28 ± 7 yr of age; 25 females; average body mass index, 41.0 ± 4.7 kg/m2) were enrolled. Median PEEP with highest dynamic compliance during titration was 15 cm H2O (interquartile range, 13 to 17; range, 8 to 19) in the entire sample of 40 patients. The primary outcome of postoperative atelectasis (available in 19 patients in each group) was 13.1 ± 5.3% and 9.5 ± 4.3% in the PEEP of 8 cm H2O and dynamic compliance-guided PEEP groups, respectively (intergroup difference, 3.7%; 95% CI, 0.5 to 6.8%; P = 0.025). Pao2/Fio2 at 1 h after pneumoperitoneum was higher in the dynamic compliance-guided PEEP group (397 vs. 337 mmHg; group difference, 60; 95% CI, 9 to 111; P = 0.017) but did not differ between the two groups 30 min after extubation (359 vs. 375 mmHg; group difference, -17; 95% CI, -53 to 21; P = 0.183). The incidence of postoperative pulmonary complications was 4 of 20 in both groups.
CONCLUSIONS
Postoperative atelectasis was lower in patients undergoing laparoscopic bariatric surgery under dynamic compliance-guided PEEP versus PEEP of 8 cm H2O. Postoperative Pao2/Fio2 did not differ between the two groups.
Topics: Female; Humans; Positive-Pressure Respiration; Pulmonary Atelectasis; Obesity; Lung; Respiratory Distress Syndrome
PubMed: 37440205
DOI: 10.1097/ALN.0000000000004603 -
Anesthesiology Jun 2022
Topics: Humans; Lung; Positive-Pressure Respiration; Pulmonary Atelectasis; Respiration
PubMed: 35362084
DOI: 10.1097/ALN.0000000000004193 -
Anesthesiology Jan 2015
Topics: Anesthesia, General; Female; Humans; Lung; Male; Pulmonary Atelectasis; Ultrasonography
PubMed: 25611661
DOI: 10.1097/ALN.0000000000000500