Seated and semi-recumbent positioning of the ventilated intensive care patient - effect on gas exchange, respiratory mechanics and hemodynamics

Semirecumbent Positioning During Anesthesia Recovery and Postoperative Hypoxemia: A Randomized Clinical Trial

Importance

The efficacy of a semirecumbent position (SRP) in reducing postoperative hypoxemia during anesthesia emergence is unclear despite its widespread use.

Objective

To determine the differences in postoperative hypoxemia between patients in an SRP and a supine position.

Design, Setting, and Participants

This randomized clinical trial was performed at a tertiary hospital in China between March 20, 2021, and May 10, 2022. Patients scheduled to undergo laparoscopic upper abdominal surgery under general anesthesia were enrolled. Study recruitment and follow-up are complete.

Interventions

Patients were randomized to 1 of the following positions at the end of the operation until leaving the postanesthesia care unit: supine (group S), 15° SRP (group F), or 30° SRP (group T).

Main Outcomes and Measures

The primary outcome was the incidence of postoperative hypoxemia in the postanesthesia care unit. Severe hypoxemia was also evaluated.

Results

Out of 700 patients (364 men [52.0%]; mean [SD] age, 47.8 [11.3] years), 233 were randomized to group S (126 men [54.1%]; mean [SD] age, 48.2 [10.9] years), 233 to group F (122 men [52.4%]; mean [SD] age, 48.1 [10.9] years), and 234 to group T (118 women [50.4%]; mean [SD] age, 47.2 [12.1] years). Postoperative hypoxemia differed significantly among the 3 groups (group S, 109 of 233 [46.8%]; group F, 105 of 233 [45.1%]; group T, 76 of 234 [32.5%]; P = .002). This difference was statistically significant for groups T vs S (risk ratio [RR], 0.69 [95% CI, 0.55-0.87]; P = .002) and groups T vs F (RR, 0.72 [95% CI, 0.57-0.91]; P = .007), but not for groups F vs S (RR, 0.96 [95% CI, 0.79-1.17]; P = .78). Severe hypoxemia also differed among the 3 groups (group S, 61 of 233 [26.2%]; group F, 53 of 233 [22.7%]; group T, 36 of 234 [15.4%]; P = .01). This difference was statistically significant for groups T vs S (RR, 0.59 [95% CI, 0.41-0.85]; P = .005).

Conclusions and Relevance

In this randomized clinical trial of SRP during anesthesia recovery in patients undergoing laparoscopic upper abdominal surgery, postoperative hypoxemia was significantly reduced in group T compared with group F or group S.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2100045087.

Comparator Groups in ICU-Based Studies of Physical Rehabilitation: A Scoping Review of 125 Studies

To characterize comparator groups (CGs) in ICU-based studies of physical rehabilitation (PR), including the type, content, and reporting.

DATA SOURCES

We followed a five-stage scoping review methodology, searching five databases from inception to June 30, 2022. Study selection and data extraction were completed independently, in duplicate.

STUDY SELECTION

We screened studies by title and abstract, then full-text. We included prospective studies with greater than or equal to two arms enrolling mechanically ventilated adults (≥ 18 yr), with any planned PR intervention initiated in the ICU.

DATA EXTRACTION

We conducted a quantitative content analysis of authors' description of CG type and content. We categorized similar CG types (e.g., usual care), classified content into unique activities (e.g., positioning), and summarized these data using counts (proportions). We assessed reporting using Consensus on Exercise Reporting Template (CERT; proportion of reported items/total applicable).

DATA SYNTHESIS

One hundred twenty-five studies were included, representing 127 CGs. PR was planned in 112 CGs (88.2%; 110 studies), representing four types: usual care (n = 81, 63.8%), alternative treatment than usual care (e.g., different from intervention; n = 18, 14.2%), alternative treatment plus usual care (n = 7, 5.5%), and sham (n = 6, 4.7%). Of 112 CGs with planned PR, 90 CGs (88 studies) reported 60 unique activities, most commonly passive range of motion (n = 47, 52.2%). The remaining 22 CGs (19.6%; 22 studies) reported vague descriptions. PR was not planned in 12 CGs (9.5%; 12 studies), and three CGs (2.4%; three studies) reported no details. Studies reported a median (Q1-Q3) of 46.6% (25.0-73.3%) CERT items. Overall, 20.0% of studies reported no detail to understand planned CG activities.

CONCLUSIONS

The most common type of CG was usual care. We identified heterogeneity in planned activities and CERT reporting deficiencies. Our results could help guide the selection, design, and reporting of CGs in future ICU-based PR studies.

Total and Compartmental Chest Wall Volumes, Lung Function, and Respiratory Muscle Strength in Individuals with Abdominal Obesity: Effects of Body Positions

Background

Abdominal obesity is a chronic condition that can contribute to impairments in lung function, leading to increased risks for respiratory-related diseases. Body position is an important technique that effectively restores and increases lung function and chest wall volumes. The objective of the current study was to examine the effects of the body positions on total and compartmental chest wall volumes, lung function, and respiratory muscle strength in individuals with and without abdominal obesity.

Methods

Twenty obesity and twenty healthy males performed in four body position including sitting without and with back support, Fowler's, and supine positions. Each position was performed for five minutes. Chest wall volumes, lung function, and respiratory muscle strength were assessed in each position.

Results

Sitting without and with back support resulted in higher total and rib cage compartmental chest wall volumes, lung function, and inspiratory muscle strength than Fowler's and supine positions in both groups (p < 0.001). Abdominal obesity subjects had significantly less total and compartmental chest wall volumes and lung function across four body positions than healthy subjects (p < 0.001). Respiratory muscle strength in the obesity group was less than that in the healthy control group (p > 0.05).

Conclusions

This study provides new information regarding the effect of obesity and body position on chest wall volumes, lung function, and respiratory muscle strength. Among obesity individuals who are bedridden, sitting increases lung function, total and rib cage compartmental chest wall volumes, and inspiratory muscle strength-and would therefore likely to decrease the risk of respiratory-related disease-relative to Fowler's and supine positions.

Physical rehabilitation interventions in the intensive care unit: a scoping review of 117 studies

BACKGROUND

Physical rehabilitation (PR) interventions in the intensive care unit (ICU) can improve patients' functional outcomes, yet systematic reviews identified discordant effects and poor reporting. We conducted a scoping review to determine the extent of ICU PR interventions and how they were reported and measured.

METHODS

We searched five databases from inception to December 2016 for prospective studies evaluating adult ICU PR interventions. Two independent reviewers screened titles, abstracts, and full texts for inclusion. We assessed completeness of reporting using the Consolidated Standards of Reporting Trials, Strengthening the Reporting of Observational Studies in Epidemiology, or Standards for Quality Improvement Reporting Excellence guidelines, as appropriate. For planned PR interventions, we evaluated reporting with the Consensus on Exercise Reporting Template (CERT) and assessed intervention and control groups separately. We calculated completeness of reporting scores for each study; scores represented the proportion of reported items. We compared reporting between groups using Kruskal-Wallis with Bonferroni corrections and t tests, α = 0.05.

RESULTS

We screened 61,774 unique citations, reviewed 1429 full-text publications, and included 117: 39 randomized trials, 30 case series, 9 two-group comparison, 14 before-after, and 25 cohort. Interventions included neuromuscular electrical stimulation (NMES) (14.5%), passive/active exercises (15.4%), cycling (6.8%), progressive mobility (32.5%), and multicomponent (29.9%). The median (first,third quartiles) study reporting score was 75.9% (62.5, 86.7) with no significant differences between reporting guidelines. Of 87 planned intervention studies, the median CERT score was 55.6%(44.7,75.0); cycling had the highest (85.0%(62.2,93.8)), and NMES and multicomponent the lowest (50.0% (39.5, 70.3) and 50.0% (41.5, 58.8), respectively) scores. Authors reported intervention groups better than controls (p < 0.001).

CONCLUSIONS

We identified important reporting deficiencies in ICU PR interventions, limiting clinical implementation and future trial development.

Effects of patient positioning on respiratory mechanics in mechanically ventilated ICU patients

Changes in the body position of patients receiving mechanical ventilation in intensive care unit are frequent. Contrary to healthy humans, little data has explored the physiological impact of position on respiratory mechanics. The objective of present paper is to review the available data on the effect of changing body position on respiratory mechanics in ICU patients receiving mechanical ventilation. Supine position (lying flat) or lateral position do not seem beneficial for critically ill patients in terms of respiratory mechanics. The sitting position (with thorax angulation >30° from the horizontal plane) is associated with improvement of functional residual capacity (FRC), oxygenation and reduction of work of breathing. There is a critical angle of inclination in the seated position above which the increase in abdominal pressure contributes to increase chest wall elastance and offset the increase in FRC. The impact of prone position on respiratory mechanics is complex, but the increase in chest wall elastance is a central mechanism. To sum up, both sitting and prone positions provides beneficial impact on respiratory mechanics of mechanically ventilated patients as compared to supine position.

Effect of Recumbent Body Positions on Dynamic Lung Function Parameters in Healthy Young Subjects

INTRODUCTION

The change in body position can alter pulmonary functions parameters, therefore it is important to understand the physiological basis of these alteration. Ideally, spirometry is done in sitting position until the subject is unable to do so. Hospitalized patients often assume recumbent body positions irrespective of underlying pathology. Hence, need arises to find out best recumbent body positions for the benefit of these patients to make breathing comfortable for them.

AIM

The aim of this study was to find out whether the change from the supine position to crook lying and Fowler's position (45° dorsal elevation) causes change in spirometric parameters.

MATERIALS AND METHODS

The present work was carried out at Department of Physiology, King George's Medical University, Lucknow. A total 131 apparently healthy individuals were enrolled in this cross-sectional study. Lung function was assessed using a PC-based spirometer according to American Thoracic Society guideline in the supine, crook lying and Fowler's position (45° dorsal elevation).

RESULTS

The study consisted of 131 subjects (male 66%, female 34%), with mean age of 20.15±2.71 years and BMI 21.20±3.28 Kg/m². Repeated measures ANOVA with post hoc Bonferroni test was used to compare the mean values between each body position. Compared with the other two positions, Fowler's position showed significantly (p<0.05) higher values for FVC, FEV₁, PEF, FEF_25-75%.

CONCLUSION

Recumbent body position influences spirometric parameters in young healthy subjects. We demonstrated that spirometric values are higher in the Fowler's position than in the supine or crook lying position. The results of this study will help in the selection of the best alternative position for the spirometry in bed ridden patients.

[Physiotherapy interventions in the ICU : Outcome-relevant measurement parameters]

BACKGROUND

Guidelines cannot provide differentiated recommendations for physiotherapy (PT) in intensive care medicine. Scientific publications for PT in the intensive care unit (ICU) usually only have low levels of evidence and often express safety and feasibility of PT in the ICU.

OBJECTIVE

Which measurement parameters are relevant for defining outcome and what interventions should one take into consideration?

MATERIALS AND METHODS

A literature review was conducted. This was based on a PubMed search with full text access, as well as specific definitions for physical therapy, intensive care and four out of seven conditions from the manual "Physiotherapy in intensive care".

RESULTS

The availability of 172 studies clearly shows that there is certainly PT research concerning the critical environment of the ICU. However, parameters for quantitative and qualitative detection of vigilance and state of consciousness as well as assessments to evaluate the mobility and the ability to help themselves are important for everyday use.

CONCLUSIONS

The difficulties of using PT in the ICU are not useful in ensuring the safety of the patient or performing a PT treatment. The conditions of the intensive care environment are not an obstacle. It is of immanent importance to use the limited resources of PT in an optimal and targeted manner in the ICU environment. The determination of ICU-adapted goals plays a crucial role.

Teamwork enables high level of early mobilization in critically ill patients

BACKGROUND

Early mobilization in critically ill patients has been shown to prevent bed-rest-associated morbidity. Reported reasons for not mobilizing patients, thereby excluding or delaying such intervention, are diverse and comprise safety considerations for high-risk critically ill patients with multiple organ support systems. This study sought to demonstrate that early mobilization performed within the first 24 h of ICU admission proves to be feasible and well tolerated in the vast majority of critically ill patients.

RESULTS

General practice data were collected for 171 consecutive admissions to our ICU over a 2-month period according to a local, standardized, early mobilization protocol. The total period covered 731 patient-days, 22 (3 %) of which met our local exclusion criteria for mobilization. Of the remaining 709 patient-days, early mobilization was achieved on 86 % of them, bed-to-chair transfer on 74 %, and at least one physical therapy session on 59 %. Median time interval from ICU admission to the first early mobilization activity was 19 h (IQR = 15-23). In patients on mechanical ventilation (51 %), accounting for 46 % of patient-days, 35 % were administered vasopressors and 11 % continuous renal replacement therapy. Within this group, bed-to-chair transfer was achieved on 68 % of patient-days and at least one early mobilization activity on 80 %. Limiting factors to start early mobilization included restricted staffing capacities, diagnostic or surgical procedures, patients' refusal, as well as severe hemodynamic instability. Hemodynamic parameters were rarely affected during mobilization, causing interruption in only 0.8 % of all activities, primarily due to reversible hypotension or arrhythmia. In general, all activities were well tolerated, while patients were able to self-regulate their active early mobilization. Patients' subjective perception of physical therapy was reported to be enjoyable.

CONCLUSIONS

Mobilization within the first 24 h of ICU admission is achievable in the majority of critical ill patients, in spite of mechanical ventilation, vasopressor administration, or renal replacement therapy.