Hypoxaemia during recovery after surgery for colorectal cancer: a prospective observational study

Role of continuous pulse oximetry and capnography monitoring in the prevention of postoperative respiratory failure, postoperative opioid-induced respiratory depression and adverse outcomes on hospital wards: A systematic review and meta-analysis

OBJECTIVE

The current standards of postoperative respiratory monitoring on medical-surgical floors involve spot-pulse oximetry checks every 4-8 h, which can miss the opportunity to detect prolonged hypoxia and acute hypercapnia. Continuous respiratory monitoring can recognize acute respiratory depression episodes; however, the existing evidence is limited. We sought to review the current evidence on the effectiveness of continuous pulse oximetry (CPOX) with and without capnography versus routine monitoring and their effectiveness for detecting postoperative respiratory failure, opioid-induced respiratory depression, and preventing downstream adverse events.

METHODS

We performed a systematic literature search on Ovid Medline, Embase, and Cochrane Library databases for articles published between 1990 and April 2023. The study protocol was registered in Prospero (ID: 439467), and PRISMA guidelines were followed. The NIH quality assessment tool was used to assess the quality of the studies. Pooled analysis was conducted using the software R version 4.1.1 and the package meta. The stability of the results was assessed using sensitivity analysis.

DESIGN

Systematic Review and Meta-Analysis.

SETTING

Postoperative recovery area.

PATIENTS

56,538 patients, ASA class II to IV, non-invasive respiratory monitoring, and post-operative respiratory depression.

INTERVENTIONS

Continuous pulse oximetry with or without capnography versus routine monitoring.

MEASUREMENTS

Respiratory rate, oxygen saturation, adverse events, and rescue events.

RESULTS

23 studies (17 examined CPOX without capnography and 5 examined CPOX with capnography) were included in this systematic review. CPOX was better at recognizing desaturation (SpO2 < 90%) OR: 11.94 (95% CI: 6.85, 20.82; p < 0.01) compared to standard monitoring. No significant differences were reported for ICU transfer, reintubation, and non-invasive ventilation between the two groups.

CONCLUSIONS

Oxygen desaturation was the only outcome better detected with CPOX in postoperative patients in hospital wards. These comparisons were limited by the small number of studies that could be pooled for each outcome and the heterogeneity between the studies.

The incidence of hypoxemia in dogs recovering from general anesthesia detected with pulse-oximetry and related risk factors

The postoperative period is critical for the development of complications, including hypoxemia. To detect hypoxemia early and provide appropriate care, continuous monitoring of saturation is necessary: pulse oximetry is an easily accessible and simple method for this purpose. However, a SpO2 cut-off value to detect hypoxemia in dogs recovering from general anesthesia is lacking in the veterinary literature. The objectives of this clinical study are to validate the room air SpO2 test (SpAT), to identify a cut-off value to discriminate hypoxemia (Phase 1), and to apply the SpAT to study the incidence of transient postoperative hypoxemia (TPH) (Phase 2) in dogs with healthy lungs recovering from general anesthesia. Phase 1: 87 dogs recovering from general anesthesia with an arterial line were included. After extubation, SpAT was performed simultaneously with arterial blood sampling. A PaO2 < 80 mmHg was considered hypoxemia. Phase 2: 654 dogs were enrolled. They underwent general anesthesia with different ventilation settings for different procedures. After extubation, dogs were classified as hypoxemic if the SpO2 was lower than the cut-off obtained in phase 1. Phase 1 showed that the SpO2 cut-off is < 95% (sensitivity 100%, specificity 97.4%; area under the curve, AUC = 0.996; 95% Confidence Interval = 0.944-1; P<0.0001). In Phase 2, 169 dogs were hypoxemic. Body Condition Score (BCS) > 3/5, dorsal recumbency, FiO2 1, absence of Positive End-Expiratory Pressure (PEEP) had a significant odds ratio to induce TPH (5.8, 1.9, 3.7, 1.7, respectively). These results showed that SpO2 < 95% indicates PaO2 < 80 mmHg in dogs and TPH occurs in up to 28% of cases. Identification of associated risks could be useful to prevent and to increase awareness for monitoring and treatment.

Myocardial injury and long-term oncological outcomes in patients undergoing surgery for colorectal cancer

PURPOSE

Myocardial injury after noncardiac surgery (MINS) is associated with increased mortality and postoperative complications. In patients with colorectal cancer (CRC), postoperative complications are a risk factor for cancer recurrence and disease-free survival. This study investigates the association between MINS and long-term oncological outcomes in patients with CRC in an ERAS setting.

METHODS

This retrospective cohort study was conducted at Zealand University Hospital, Denmark, between June 2015 and July 2017. Patients undergoing CRC surgery were included if troponin was measured twice after surgery. Outcomes were all-cause mortality, recurrence, and disease-free survival within five years of surgery.

RESULTS

Among 586 patients, 42 suffered MINS. After five years, 36% of patients with MINS and 26% without MINS had died, p = 0.15. When adjusted for sex, age and UICC, the hazard ratio (aHR) for 1-year all-cause mortality, recurrence, and disease-free survival were 2.40 [0.93-6.22], 1.47 [0.19-11.29], and 2.25 [0.95-5.32] for patients with MINS compared with those without, respectively. Further adjusting for ASA status, performance status, smoking, and laparotomies, the aHR for 3- and 5-year all-cause mortality were 1.05 [0.51-2.15] and 1.11 [0.62-1.99], respectively. Similarly, the aHR for 3- and 5-year recurrence were 1.38 [0.46-4.51], and 1.49 [0.56-3.98] and for 3- and 5-year disease-free survival the aHR were 1.19 [0.63-2.23], and 1.19 [0.70-2.03].

CONCLUSION

In absolute numbers, we found no difference in all-cause mortality and recurrence in patients with and without MINS. In adjusted Cox regression analyses, the hazard was increased for all-cause mortality, recurrence, and disease-free survival in patients with MINS without reaching statistical significance.

Continuously monitored vital signs for detection of myocardial injury in high-risk patients - An observational study

Background

Patients are at risk of myocardial injury after major non‐cardiac surgery and during acute illness. Myocardial injury is associated with mortality, but often asymptomatic and currently detected through intermittent cardiac biomarker screening. This delays diagnosis, where vital signs deviations may serve as a proxy for early signs of myocardial injury. This study aimed to assess the association between continuous monitored vital sign deviations and subsequent myocardial injury following major abdominal cancer surgery and during acute exacerbation of chronic obstructive pulmonary disease.

Methods

Patients undergoing major abdominal cancer surgery or admitted with acute exacerbation of chronic obstructive pulmonary disease had daily troponin measurements. Continuous wireless monitoring of several vital signs was performed for up to 96 h after admission or surgery. The primary exposure was cumulative duration of peripheral oxygen saturation (SpO₂) below 85% in the 24 h before the primary outcome of myocardial injury, defined as a new onset ischaemic troponin elevation assessed daily. If no myocardial injury occurred, the primary exposure was based on the first 24 h of measurement.

Results

A total of 662 patients were continuously monitored and 113 (17%) had a myocardial injury. Cumulative duration of SpO₂ < 85% was significantly associated with myocardial injury (mean difference 14.2 min [95% confidence interval −4.7 to 33.1 min]; p = .005). Durations of hypoxaemia (SpO₂ < 88% and SpO₂ < 80%), tachycardia (HR > 110 bpm and HR > 130 bpm) and tachypnoea (RR > 24 min⁻¹ and RR > 30 min⁻¹) were also significantly associated with myocardial injury (p < .04, for all).

Conclusion

Duration of severely low SpO₂ detected by continuous wireless monitoring is significantly associated with myocardial injury in high‐risk patients admitted to hospital wards. The effect of early detection and interventions should be assessed next.

Effects of preoperative physiotherapy on signs and symptoms of pulmonary collapse and infection after major abdominal surgery: secondary analysis of the LIPPSMAck-POP multicentre randomised controlled trial

Background

Preoperative education and breathing exercise training by a physiotherapist minimises pulmonary complications after abdominal surgery. Effects on specific clinical outcomes such as antibiotic prescriptions, chest imaging, sputum cultures, oxygen requirements, and diagnostic coding are unknown.

Methods

This post hoc analysis of prospectively collected data within a double-blinded, multicentre, randomised controlled trial involving 432 participants having major abdominal surgery explored effects of preoperative education and breathing exercise training with a physiotherapist on postoperative antibiotic prescriptions, hypoxemia, sputum cultures, chest imaging, auscultation, leukocytosis, pyrexia, oxygen therapy, and diagnostic coding, compared to a control group who received a booklet alone. All participants received standardised postoperative early ambulation. Outcomes were assessed daily for 14 postoperative days. Analyses were intention-to-treat using adjusted generalised multivariate linear regression.

Results

Preoperative physiotherapy was associated with fewer antibiotic prescriptions specific for a respiratory infection (RR 0.52; 95% CI 0.31 to 0.85, p = 0.01), less purulent sputum on the third and fourth postoperative days (RR 0.50; 95% CI 0.34 to 0.73, p = 0.01), fewer positive sputum cultures from the third to fifth postoperative day (RR 0.17; 95% CI 0.04 to 0.77, p = 0.01), and less oxygen therapy requirements (RR 0.49; 95% CI 0.31 to 0.78, p = 0.002). Treatment effects were specific to respiratory clinical coding domains.

Conclusions

Preoperative physiotherapy prevents postoperative pulmonary complications and is associated with the minimisation of signs and symptoms of pulmonary collapse/consolidation and airway infection and specifically results in reduced oxygen therapy requirements and antibiotic prescriptions.

Trial registration

ANZCTR 12613000664741; 19/06/2013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-021-00206-3.

Perioperative high inspired oxygen fraction induces atelectasis in patients undergoing abdominal surgery: A randomized controlled trial

STUDY OBJECTIVE

We evaluated the feasibility of use and effects on postoperative atelectasis and complications of lower inspired oxygen fraction (FIO₂) compared to conventional oxygen therapy.

DESIGN

Single center, randomized clinical trial.

SETTING

University hospital, operating room and postoperative recovery area.

PATIENTS

One hundred ninety patients aged ≥50 with an American Society of Anesthesiologists physical status of I-III who underwent abdominal surgery with general anesthesia.

INTERVENTIONS

Participants were randomly assigned to either the low FIO₂ group (intraoperative: FIO₂ 0.35, during induction and recovery: FIO₂ 0.7) or the conventional FIO₂ group (intraoperative: FIO₂ 0.6, during induction and recovery: FIO₂ 1.0).

MEASUREMENTS

The primary outcome was postoperative atelectasis measured with lung ultrasonography at postoperative 30 min in the post-anesthesia care unit (consolidation score: each region 0-3, 12 region, total score range of 0 to 36, a lower score indicating better aeration).

MAIN RESULTS

Seven patients in the low FIO₂ group were omitted from the study due to changing FIO₂ during intervention (7/95 (8.4%) vs. 2/95 (2.1%), p = 0.088; low FIO₂ group vs. conventional FIO₂ group). Overall, atelectasis was detected in 29.7% (51/172) of patients 30 min after surgery by lung ultrasound and 40.1% (69/172) of patients after 2 days after surgery by chest X-ray. The scores of lung ultrasonography and the incidence of significant atelectasis (consolidation score ≥ 2 at any region) were lower in the low FIO₂ group than in the conventional FIO₂ group (median [IQR]: 3 [1,6] vs. 7 [3,9], p < 0.001 and 17/85 (20%) vs. 34/87 (39%), RR: 0.512 [95% CI: 0.311-0.843], p = 0.006, respectively). The incidence of surgical site infection and length of hospitalization were not significantly different between the two groups.

CONCLUSIONS

Based on our findings, decreased inspired oxygen fraction during anesthesia and recovery did not cause hypoxic events, but instead reduced immediate postoperative atelectasis. The use of intraoperative conventional higher inspired oxygen did not afford any clinical advantages for postoperative recovery in abdominal surgery.

Hypoxemia following hospital discharge after fast-track hip and knee arthroplasty - A prospective observational study subanalysis

BACKGROUND

Post-operative hypoxemia is prevalent in hospitalized patients and may adversely affect recovery. However, little data exist on the post-discharge phase or details on duration, severity and potential risk factors. Thus, we investigated the incidence and risk factors for severe desaturation during the first post-operative week after THA/TKA by continuous nocturnal oxygen saturation monitoring.

METHODS

The study was a secondary analysis of a prospective cohort study of 112 patients undergoing fast-track THA/TKA. Patients with known sleep apnoea were excluded. Oxygen saturation and heart rate were recorded by a wireless wrist-worn pulse oximeter 2 nights before and 7 nights after surgery. Data on demographics, opioid consumption and cognitive function were collected from medical charts, patient diaries and clinical testing respectively. The primary outcome was occurrence of severe desaturation defined as periods with saturation <85% lasting ≥10 minutes. Secondary outcomes included description of various saturation levels and relevant risk factors.

RESULTS

Severe oxygen desaturation occurred in 35% of the patients during the first post-operative week. Duration and severity of hypoxemic episodes increased after the first post-operative day. Pre-operative episodes of hypoxemia significantly increased the risk of post-operative hypoxemic events (OR 2.4-4.4, CI 0.4-46), while pre- and post-operative opioid use, age, gender, ASA classification, type of surgery or anaesthesia were significantly related to the development of post-operative hypoxemia.

CONCLUSIONS

One third of the patients suffered from increased and prolonged episodes of severe nocturnal hypoxemia during the first week after THA/TKA discharge. Increased risk for severe hypoxemic episodes was related to pre-operative hypoxemia.

Noninvasive respiratory support in the hypoxaemic peri-operative/periprocedural patient: a joint ESA/ESICM guideline

Hypoxaemia is a potential life-threatening yet common complication in the peri-operative and periprocedural patient (e.g. during an invasive procedure at risk of deterioration of gas exchange, such as bronchoscopy). The European Society of Anaesthesiology (ESA) and the European Society of Intensive Care Medicine (ESICM) developed guidelines for the use of noninvasive respiratory support techniques in the hypoxaemic patient in the peri-operative and periprocedural period. The panel outlined five clinical questions regarding treatment with noninvasive respiratory support techniques [conventional oxygen therapy (COT), high flow nasal cannula, noninvasive positive pressure ventilation (NIPPV) and continuous positive airway pressure (CPAP)] for hypoxaemic patients with acute peri-operative/periprocedural respiratory failure. The goal was to assess the available literature on the various noninvasive respiratory support techniques, specifically studies that included adult participants with hypoxaemia in the peri-operative/periprocedural period. The literature search strategy was developed by a Cochrane Anaesthesia and Intensive Care trial search specialist in close collaboration with the panel members and the ESA group methodologist. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the level of evidence and to grade recommendations. The final process was then validated by both ESA and ESICM scientific committees. Among 19 recommendations, the two grade 1B recommendations state that: in the peri-operative/periprocedural hypoxaemic patient, the use of either NIPPV or CPAP (based on local expertise) is preferred to COT for improvement of oxygenation; and that the panel suggests using NIPPV or CPAP immediately post-extubation for hypoxaemic patients at risk of developing acute respiratory failure after abdominal surgery.