Pulse oximeter oxygen saturation in prediction of arterial oxygen saturation in liver transplant candidates

Risk factors for hypoxaemia following hip fracture surgery in elderly patients who recovered from COVID-19: a multicentre retrospective study

Objectives

To explore the risk factors associated with postoperative hypoxaemia in elderly patients who have recovered from coronavirus disease (COVID-19) and underwent hip fracture surgery in the short term.

Design

Multicentre retrospective study.

Setting

The study was performed in three first 3A-grade hospitals in China.

Participants

A sequential sampling method was applied to select study participants. Medical records of 392 patients aged ≥65 years who had recovered from COVID-19 and underwent hip fracture surgery at three hospitals in China between 1 November, 2022, and 15 February, 2023, were reviewed.

Interventions

Patients were assigned to hypoxaemia or non-hypoxaemia groups, according to whether hypoxaemia occurred after surgery. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for postoperative hypoxaemia.

Results

The incidence of postoperative hypoxaemia was 38.01%. Statistically significant differences were found between the two groups in terms of age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, presence of expectoration symptoms, preoperative hypoxaemia, chronic obstructive pulmonary disease, pulmonary inflammation, time between recovery from COVID-19 and surgery, anaesthetic mode, surgical procedure, intraoperative blood loss, intraoperative infusion, duration of surgery, and length of hospital stay (p < 0.05). Furthermore, patients with BMI ≥28.0 kg/m², expectoration symptoms, presence of preoperative hypoxaemia, ASA classification III, time between recovery from COVID-19 and surgery ≤2 weeks, and general anaesthesia were potential risk factors for postoperative hypoxaemia.

Conclusion

Obesity, expectoration symptoms, preoperative hypoxaemia, ASA classification III, time between recovery from COVID-19 and surgery ≤2 weeks, and general anaesthesia were potential risk factors for postoperative hypoxaemia in elderly patients who recovered from COVID-19 and underwent hip fracture surgery in the short term.

Accuracy of two pulse-oximetry measurements for INTELLiVENT-ASV in mechanically ventilated patients: a prospective observational study

Recently, maintaining a certain oxygen saturation measured by pulse oximetry (SpO₂) range in mechanically ventilated patients was recommended; attaching the INTELLiVENT-ASV to ventilators might be beneficial. We evaluated the SpO₂ measurement accuracy of a Nihon Kohden and a Masimo monitor compared to actual arterial oxygen saturation (SaO₂). SpO₂ was simultaneously measured by a Nihon Kohden and Masimo monitor in patients consecutively admitted to a general intensive care unit and mechanically ventilated. Bland–Altman plots were used to compare measured SpO₂ with actual SaO₂. One hundred mechanically ventilated patients and 1497 arterial blood gas results were reviewed. Mean SaO₂ values, Nihon Kohden SpO₂ measurements, and Masimo SpO₂ measurements were 95.7%, 96.4%, and 96.9%, respectively. The Nihon Kohden SpO₂ measurements were less biased than Masimo measurements; their precision was not significantly different. Nihon Kohden and Masimo SpO₂ measurements were not significantly different in the “SaO₂ < 94%” group (P = 0.083). In the “94% ≤ SaO₂ < 98%” and “SaO₂ ≥ 98%” groups, there were significant differences between the Nihon Kohden and Masimo SpO₂ measurements (P < 0.0001; P = 0.006; respectively). Therefore, when using automatically controlling oxygenation with INTELLiVENT-ASV in mechanically ventilated patients, the Nihon Kohden SpO₂ sensor is preferable.

Trial registration UMIN000027671. Registered 7 June 2017.

A multicentre prospective observational study comparing arterial blood gas values to those obtained by pulse oximeters used in adult patients attending Australian and New Zealand hospitals

Background

Pulse oximetry is widely used in the clinical setting. The purpose of this validation study was to investigate the level of agreement between oxygen saturations measured by pulse oximeter (SpO₂) and arterial blood gas (SaO₂) in a range of oximeters in clinical use in Australia and New Zealand.

Methods

Paired SpO₂ and SaO₂ measurements were collected from 400 patients in one Australian and two New Zealand hospitals. The ages of the patients ranged from 18 to 95 years. Bias and limits of agreement were estimated. Sensitivity and specificity for detecting hypoxaemia, defined as SaO₂ < 90%, were also estimated.

Results

The majority of participants were recruited from the Outpatient, Ward or High Dependency Unit setting. Bias, oximeter-measured minus arterial blood gas-measured oxygen saturation, was − 1.2%, with limits of agreement − 4.4 to 2.0%. SpO₂ was at least 4% lower than SaO₂ for 10 (2.5%) of the participants and SpO₂ was at least 4% higher than the SaO₂ in 3 (0.8%) of the participants. None of the participants with a SpO₂ ≥ 92% were hypoxaemic, defined as SaO₂ < 90%. There were no clinically significant differences in oximetry accuracy in relation to clinical characteristics or oximeter brand.

Conclusions

In the majority of the participants, pulse oximetry was an accurate method to assess SaO₂ and had good performance in detecting hypoxaemia. However, in a small proportion of participants, differences between SaO₂ and SpO₂ could have clinical relevance in terms of patient monitoring and management. A SpO₂ ≥ 92% indicates that hypoxaemia, defined as a SaO₂ < 90%, is not present.

Trial registration

Australian and New Zealand Clinical Trials Registry (ACTRN12614001257651). Date of registration: 2/12/2014.

Accuracy of pulse oximeters in detecting hypoxemia in patients with chronic thromboembolic pulmonary hypertension

Purpose

Pulse oximetry is routinely used to continuously and non-invasively monitor arterial oxygen saturation (SaO₂). When oxygen saturation by pulse oximeter (SpO₂) overestimates SaO₂, hypoxemia may be overlooked. We compared the SpO₂ - SaO₂ differences among three pulse oximeters in patients with chronic thromboembolic pulmonary hypertension (CTEPH) who spent their daily lives in a poor oxygen state.

Material and Method

This prospective observational study recruited 32 patients with CTEPH undergoing elective cardiac catheterization. As we collected arterial blood samples in the catheter laboratory, SpO₂ values were simultaneously recorded. Three pulse oximeters were used on each patient, and SpO₂ values were compared with oximetry readings using a blood gas analyzer. To determine the optimal SpO₂ value by which to detect hypoxemia (SaO₂≦90%), we generated receiver operating characteristic (ROC) curves for each pulse oximeter.

Result

The root mean square of each pulse oximeter was 1.79 (OLV-3100), 1.64 (N-BS), and 2.50 (Masimo Radical). The mean bias (SpO₂ - SaO₂) for the 90%–95% saturation range was significantly higher for Masimo Radical (0.19 +/- 1.78% [OLV-3100], 0.18 +/- 1.63% [N-BS], and 1.61 +/- 1.91% [Masimo Radical]; p<0.0001). The optimal SpO₂ value to detect hypoxemia (SaO₂≦90%) was 89% for OLV-3100, 90% for N-BS, and 92% for Masimo Radical.

Conclusion

We found that the biases and precision with which to detect hypoxemia differed among the three pulse oximeters. To avoid hypoxemia, the optimal SpO₂ should be determined for each pulse oximeter.

The role of inhalational anesthetic drugs in patients with hepatic dysfunction: a review article

Context:

Anesthetic drugs including halogenated anesthetics have been common for many years. Consequent hepatic injury has been reported in the literature. The mechanism of injury is immunoallergic. The first generation drug was halothane; it had the most toxicity when compared to other drugs. The issue becomes more important when the patient has an underlying hepatic dysfunction.

Evidence Acquisition:

In this paper, reputable internet databases from 1957–2014 were analyzed and 43 original articles, 3 case reports, and 3 books were studied. A search was performed based on the following keywords: inhalational anesthesia, hepatic dysfunction, halogenated anesthetics, general anesthesia in patients with hepatic diseases, and side effects of halogenated anesthetics from reliable databases. Reputable websites like PubMed and Cochrane were used for the searches.

Results:

In patients with hepatic dysfunction in addition to hepatic system and dramatic hemostatic dysfunction, dysfunction of cardiovascular, renal, respiratory, gastrointestinal, and central nervous systems may occur. On the other hand, exposure to inhalational halogenated anesthetics may have a negative impact (similar to hepatitis) on all aforementioned systems in addition to direct effects on liver function as well as the effects are more pronounced in halothane.

Conclusions:

Despite the adverse effects of inhalational halogenated anesthetics (especially halothane) on hepatic patients when necessary. The effects on all systems must be considered and the necessary preparations must be provided. These drugs are still used, if necessary, due to the presence of positive effects and advantages mentioned in other studies as well as the adverse effects of other drugs.