Effects of hypercarbia on arterial oxygenation during one-lung ventilation: prospective randomized crossover study

Effect of ultrasound-guided stellate ganglion block on lung protection for patients undergoing one-lung ventilation

OBJECTIVE

To explore the potential effect of ultrasound-guided stellate ganglion block (SGB) on lung protection for patients undergoing one-lung ventilation (OLV).

METHODS

A total of 123 patients undergoing elective one-lung ventilation surgery were selected as research subjects in this prospective study. These patients were randomly divided into the SGB group, control group and blank group on average. Stellate ganglion block was carried out in the SGB and control groups. Patients in the SGB group were injected with 6 ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, while those in the control group were injected with 6 mL of 0.9% saline. Punctures weren't performed for patients in the blank group. The same induction and maintenance of general anesthesia was adopted for all three groups. Hemodynamics, respiratory parameters and arterial blood gas analysis were recorded after entering the operation room (T0), pre-OLV (T1), 30 min after OLV (T2), 60 min after OLV (T3), at the end of surgery (T4), and 30 min after extubation (T5). Oxygenation index (OI), pulmonary shunt fraction (Qs/Qt) and pH value were compared at different time points. Intravenous serum was collected at T0, T3 and T5 for the detection of surfactant proteins A (SP-A), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-6 (IL-6) and interleukin-10 (IL-10) levels, respectively. The complications related to SGB after surgery and the postoperative pulmonary complications within 72 h were recorded.

RESULTS

At T1, T2, and T3, MAP level in SGB group was lower than that in blank and control groups (P<0.05). At T2, and T3, SGB group had lower hear rate (HR), peak airway pressure (Ppeak) and tidal volume (TV) than blank and control groups (all P<0.05). From T2 to T5, SGB group had higher OI but lower Qs/Qt than blank and control groups (both P<0.05). At T3 and T5, SGB group had lower SP-A, IL-6, and MDA levels but higher IL-10 and SOD levels than blank and control groups (all P<0.05). There was one case of hypoxemia in the blank group within 72 h after surgery.

CONCLUSION

Ultrasound-guided SGB has lung-protective effects on patients undergoing OLV, which significantly improves patients' OI, reduces intrapulmonary shunts, declines ventilator-induced lung damage, and inhibits inflammatory response as well as oxidative stress (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

Effect of permissive hypercarbia on lung oxygenation during one-lung ventilation and postoperative pulmonary complications in patients undergoing thoracic surgery: A prospective randomised controlled trial

BACKGROUND

The effect of hypercarbia on lung oxygenation during thoracic surgery remains unclear.

OBJECTIVE

To investigate the effect of hypercarbia on lung oxygenation during one-lung ventilation in patients undergoing thoracic surgery and evaluate the incidence of postoperative pulmonary complications.

DESIGN

Prospective randomised controlled trial.

SETTING

A tertiary university hospital in the Republic of Korea from November 2019 to December 2020.

PATIENTS

Two hundred and ninety-seven patients with American Society of Anaesthesiologists physical status II to III, scheduled to undergo elective lung resection surgery.

INTERVENTION

Patients were randomly assigned to Group 40, 50, or 60. An autoflow ventilation mode with a lung protective ventilation strategy was applied to all patients. Respiratory rate was adjusted to maintain a partial pressure of arterial carbon dioxide of 40 ± 5 mmHg in Group 40, 50 ± 5 mmHg in Group 50 and 60 ± 5 mmHg in Group 60 during one-lung ventilation and at the end of surgery.

MAIN OUTCOME MEASURES

The primary outcome was the arterial oxygen partial pressure/fractional inspired oxygen ratio after 60 min of one-lung ventilation.

RESULTS

Data from 262 patients were analysed. The partial pressure/fractional inspired oxygen ratio was significantly higher in Group 50 and Group 60 than in Group 40 (269.4 vs. 262.9 vs. 214.4; P  < 0.001) but was not significantly different between Group 50 and Group 60. The incidence of postoperative pulmonary complications was comparable among the three groups.

CONCLUSION

Permissive hypercarbia improved lung oxygenation during one-lung ventilation without increasing the risk of postoperative pulmonary complications or the length of hospital stay.

TRIAL REGISTRATION

NCT04175379.

Lung ultrasound score-based assessment of postoperative atelectasis in obese patients according to inspired oxygen concentration: A prospective, randomized-controlled study

BACKGROUND

According to a recent meta-analysis, in patients with a body mass index (BMI) ≥ 30, a high fraction of inhaled oxygen (FiO2) did not increase postoperative atelectasis. However, a high FiO2 generally increases the risk of postoperative atelectasis. Therefore, this study aimed to evaluate the effect of FiO2 on the development of atelectasis in obese patients using the modified lung ultrasound score (LUSS).

METHODS

Patients were assigned to 4 groups: BMI ≥ 30: group A (n = 21) and group B (n = 20) and normal BMI: group C (n = 22) and group D (n = 21). Groups A and C were administered 100% O2 during preinduction and emergence and 50% O2 during anesthesia. Groups B and D received 40% O2 for anesthesia. The modified LUSS was assessed before and 20 min after arrival to the postanesthesia care unit (PACU).

RESULTS

The difference between the modified LUSS preinduction and PACU was significantly higher in group A with a BMI ≥ 30 (P = .006); however, there was an insignificant difference between groups C and D in the normal BMI group (P = .076).

CONCLUSION

High FiO2 had a greater effect on the development of atelectasis in obese patients than did low FiO2; however, in normal-weight individuals, FiO2 did not have a significant effect on postoperative atelectasis.

Transparency considerations for describing statistical analyses in research

Researchers who use the results of statistical analyses to draw conclusions about collected data must write a statistical analysis section in their manuscript. Describing statistical analyses in precise detail is as important as presenting the dosages of drugs and methodology of interventions. It is also essential for scientific accuracy and transparency in scientific research. We evaluated the quality of the statistical analysis sections of clinical research articles published in the Korean Journal of Anesthesiology between February 2020 and February 2021. Using a Likert scale where 1, 2, and 3 represented “not described at all,” “partially described,” and “fully described,” respectively, the following 6 items were assessed: 1) stating of the statistical analysis methods used, 2) rationale for and detailed description of the statistical analysis methods used, 3) parameters derived from the statistical analyses, 4) type and version of the statistical software package used, 5) significance level, and 6) sidedness of the test (one-sided vs. two-sided). The first 3 items evaluate issues directly related to the statistical analysis methods used and last 3 are indirectly related items. In all the included articles, the statistical analysis methods used were stated (score of 3). However, only 4 articles (12.9%) fully described the sidedness of the test (score of 3). Authors tend not to describe the sidedness of statistical analysis tests in the methodology section of clinical research articles. It is essential that the sidedness be described in research studies.