Analysis of pulmonary function and comparison of time to early mobilization in patients undergoing laparoscopic bariatric surgery: a quasi-experimental studyABSTRACT
Early mobilization applied after bariatric surgery aims to reduce postoperative complications. Notably, there is no consensus on the appropriate time to start it. This study aimed to analyze the recovery of lung function and length of stay in patients undergoing bariatric surgery at different mobilization times. Quasi-experimental, interventional study with 167 patients divided into three groups: the first 55 patients began early mobilization 6 hours after surgery (G6); other 55 patients started after 4 hours (G4) and the last 57 patients started after 2 hours (G2). Spirometry was performed preoperatively and before mobilization, the measurements obtained were forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), maximum voluntary ventilation (MVV) and forced expiratory flow by 25-75% (FEF25-75%). There was a prevalence of females (82.04%), hospitalization time was shorter in G2 (p<0.050) and vital signs remained at physiological values. There was a significant reduction in FEV1, FVC, MVV, FEF25-75% and PEF values in the immediately after surgery, followed by a gradual increase (p≤0.05) as the days progressed. This study identified that the physiotherapeutic protocol initiated 2, 4 or 6 hours after surgery was effective regarding hemodynamic stability, reduction of hospitalization time and recovery of lung function over time in patients undergoing bariatric surgery. However, no difference was observed regarding lung function in relation to early mobilization groups.
Keywords|
Early Mobilization; Respiratory Physical Therapy; Postoperative Period
RESUMO
A mobilização precoce aplicada após cirurgia bariátrica tem o objetivo de reduzir complicações pós-operatórias, no entanto, não há consenso sobre qual é o momento adequado para iniciá-la. O objetivo deste estudo foi analisar a recuperação da função pulmonar e o tempo de internação de pacientes submetidos à cirurgia bariátrica em diferentes tempos de mobilização. Estudo quase-experimental, intervencionista com 167 pacientes divididos em três grupos: os primeiros 55 pacientes começaram a mobilização precoce 6 horas após a cirurgia (G6). Na sequência, mais 55 pacientes começaram após 4 horas (G4) e os últimos 57 pacientes deram início após 2 horas (G2). A espirometria foi realizada no pré-operatório e antes da mobilização, as medidas obtidas foram: volume expiratório forçado no primeiro segundo (VEF1), capacidade vital forçada (CVF), pico de fluxo expiratório (PFE), ventilação voluntária máxima (VVM) e fluxo expiratório forçado em 25-75% (FEF 25-75%). Houve prevalência do sexo feminino (82,04%), o tempo de internação foi menor no G2 (p<0,050) e os sinais vitais permaneceram em valores fisiológicos. Houve redução significativa dos valores de VEF1, CVF, VVM, FEF25-75% e PEF no pós-operatório imediato, seguido por aumento gradual (p≤0,05) com a evolução dos dias. O presente estudo identificou que o protocolo fisioterapêutico iniciado 2, 4 ou 6 horas no pós-operatório foi efetivo quanto à estabilidade hemodinâmica, redução do tempo de internação e recuperação da função pulmonar ao longo do tempo de pacientes submetidos à cirurgia bariátrica. No entanto, não foi observada diferença em relação à função pulmonar em grupos da mobilização precoce.
Descritores|
Mobilização Precoce; Fisioterapia Respiratória; Período Pós-Operatório
RESUMEN
La movilización temprana aplicada después de la cirugía bariátrica tiene como objetivo reducir las complicaciones posoperatorias, sin embargo, no existe consenso sobre el momento adecuado para iniciarla. El objetivo de este estudio fue analizar la recuperación de la función pulmonar y la estancia hospitalaria en pacientes sometidos a cirugía bariátrica en diferentes tiempos de movilización. Se trata de un estudio intervencionista cuasiexperimental con 167 pacientes divididos en 3 grupos: los primeros 55 pacientes iniciaron la movilización temprana 6 horas después de la cirugía (G6); otros 55 pacientes, a las 4 horas después (G4); y 57 pacientes la empezaron después de 2 horas (G2). Se realizó espirometría en el preoperatorio y antes de la movilización, las mediciones obtenidas fueron volumen espiratorio forzado en el primer segundo (VEF1), capacidad vital forzada (CVF), flujo espiratorio máximo (FEM), ventilación voluntaria máxima (VVM) y flujo espiratorio forzado a los 25-75% (FEF 25-75%). Hubo predominio del sexo femenino (82,04%), el tiempo de hospitalización fue menor en el G2 (p<0,050) y los signos vitales se mantuvieron en valores fisiológicos. Hubo una reducción significativa en los valores de VEF1, CVF, VVM, FEF 25-75% y FEM en el posoperatorio inmediato, seguido de un aumento gradual (p≤0,05) a medida que avanzaban los días. Este estudio identificó que el protocolo fisioterapéutico iniciado a las 2, 4 o 6 horas del posoperatorio fue efectivo en la estabilidad hemodinámica, la reducción del tiempo de hospitalización y recuperación de la función pulmonar en el tiempo en pacientes sometidos a cirugía bariátrica. Sin embargo, no se observaron diferencias en relación con la función pulmonar en grupos de movilización temprana.
Palabras clave|
Movilización Temprana; Fisioterapia Respiratoria; Periodo Posoperatorio
INTRODUCTION
The prevalence of obesity is steadily increasing worldwide. Approximately 39% of the adult population is overweight. Studies predict that by 2030, obesity will affect more than 20% of the world’s population, with such conditions being a risk factor for mortality due to comorbidities such as cardiovascular diseases and type 2 diabetes mellitus1), (2.
Laparoscopic bariatric surgery is recommended as an effective treatment when compared to non-surgical treatments, such as medicine therapy or intensive lifestyle interventions, to achieve significant and lasting weight loss in individuals with obesity2), (3), (4.
However, the risk of pulmonary complications must be considered after laparoscopic bariatric surgery. Restrictive pulmonary problems, reduced respiratory muscle function, and pain are common complications after surgery and may prolong hospitalization5.
In patients with morbid obesity, anesthesia may result in reduced functional residual capacity, early narrowing of the small airways, greater hypoxemia, and an increased incidence of atelectasis3), (6.
In this context, early mobilization plays a key role in preventing postoperative complications; improving and restoring lung function, muscle strength, mobility, and physical and mental well-being; in addition to reducing the length of hospital stays7.
A program consisting of physical therapy techniques that promote adequate lung ventilation, venous return and mobility during hospitalization, supervision on bed positioning, and posture maintenance is effective for patient rehabilitation and prevention of postoperative complication6), (7.
Objective
This study aimed to analyze pulmonary function recovery and length of hospital stay in patients undergoing laparoscopic bariatric surgery at different times of early mobilization.
METHODOLOGY
Quasi-experimental, interventional, double-blind (data collection and statistical analysis), non-randomized study with convenience sampling conducted at the Galileo Hospital and Maternity, in Valinhos (SP). All participants signed an informed consent form. All researchers complied with Resolution No 466/2012.
The inclusion criteria were: adults aged 18 years or older; patients who underwent laparoscopic bariatric surgery, with normal or impaired lung function, without radiological changes in the preoperative period, and those who agreed to sign the consent form. Patients who required conversion from laparoscopy to laparotomy were excluded from the study, as were those who had intraoperative adjustments in ventilatory parameters that interfered with protective mechanical ventilation (plateau pressure above 30 cmH2O and distension pressure above 15 cmH2O), hemodynamic instability with systolic blood pressure greater than 180 mmHg or less than 90 mmHg, or an increase or decrease of 20% from the preoperative value, and heart rate above 140 beats per minute, or an increase of 50% from the initial value measured preoperatively at the time scheduled to perform the physical therapy protocol.
Weight and height were measured using a Welmy® digital scale with an attached stadiometer. Body mass index was calculated according to the World Health Organization’s classification of obesity for adolescents and adults.
All pre- and postoperative pulmonary function tests were performed by the same researcher, following the Brazilian Society of Pulmonology and Phthisiology guidelines8, and in accordance with the acceptance and reproducibility criteria established and recommended by the American Thoracic Society9.
Spirometry was performed using the Contec™ Med SP10 Digital Spirometer, and the following measurements were obtained: forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), maximum voluntary ventilation (MVV), and forced expiratory flow at 25-75% (FEF 25-75%).
The FVC maneuver was performed at least three times, with at least two reproducible maneuvers, and the highest value was used for data analysis8. The reproducibility criterion for the FVC maneuver was considered to be a difference of less than 0.2 L between the highest FEV1 and FVC values after obtaining acceptable spirometry curves8.
The first 55 patients began early mobilization 6 hours after surgery (Group 6 - G6); another 55 patients started mobilization after 4 hours (Group 4 - G4); and the last 57 patients began mobilization after 2 hours (Group 2 - G2).
All groups followed the same standardized Conventional Physical Therapy protocol, established by the hospital, consisting of daily motor and respiratory physical therapy twice per day. Motor physical therapy included active mobilization of upper and lower limbs, sitting in a chair, and assisted walking supervised by the assigned physical therapist, covering 50 meters. Respiratory physical therapy consisted of voluntary fractionated breathing patterns in one, two, and three stages along with unloaded flow incentive spirometry. The first set involved raising only the first ball, the second set raising two balls, the third set raising three balls, and the fourth set raising the first ball and holding it at the spirometer marker for five seconds.
All patients were evaluated at four specific time points: preoperative (pre-op), immediate postoperative (iPO), first postoperative day (PO1), and second postoperative day (PO2). The evaluation was performed before the early mobilization session (according to each group’s designated time) and was assessed by the researcher together with the pulmonologist’s report.
In the immediate postoperative period, patients from all groups were taken from their beds and placed in a chair after their designated early mobilization start time, post-surgery. After one hour of sitting in the chair, patients performed their first assisted walk with the physical therapist while using the incentive spirometer according to the above protocol. Patients were instructed to perform the spirometer sequence along with 50-meter walks every hour during the immediate postoperative period.
On the first postoperative day, after walking 50 meters, four sets of 10 repetitions were performed with the incentive spirometer without loading. Moreover, three sets of 10 repetitions of voluntary ventilatory patterns were added, divided into one, two, and three times, respectively.
On the second and third postoperative days, in addition to the four sets of incentive spirometry and three sets of voluntary breathing patterns, three more sets of 10 repetitions of voluntary breathing patterns combined with upper limb mobilization were added. The first set consisted of 10 deep inhalations, the second of fractionated inhalations in two stages, and the third of fractionated inhalations in three stages.
In addition to the variables mentioned above, length of hospital stay was recorded, from the admission date to hospital discharge.
The sample calculation was performed with 10 individuals per group, totaling 30 individuals, based on the difference in the values observed at each moment of the study. To calculate the sample size, an analysis of variance (ANOVA) for repeated measures was performed to compare the variables between groups and times, with a 5% type I error (significance level) and a 95% test power.
The Statistical Package for the Social Sciences (SPSS; version 20.0) was used for statistical analysis. Data with non-normal distribution were presented as medians and 50% of the interquartile range. The Kolmogorov-Smirnov test was used to verify data normality. The Wilcoxon test was used for intragroup comparisons and the Kruskal-Wallis test followed by the Mann-Whitney U test for intergroup comparison. Finally, the Friedman test followed by the Wilcoxon test were used to compare times.
RESULTS
A total of 167 patients were included in the study, distributed as follows: 55 patients in G6, 55 in G4, and 57 in G2, with a prevalence of 137 women (82.04%) and 30 men (18.96%) distributed in three groups. The mean age of patients was: 34.43±9.43 years old in G6; 35.7±9.97 years old in G4; and 38.07±9.56 years old in G2. Mean length of hospital stay were: G6 4.81±0.38; G4 4.23±0.42; and G2 4. According to the analysis of the Torrington and Henderson scale criteria, all patients had a low risk of respiratory complications.
Regarding smoking, 79.04% of individuals had never smoked; 10.78% were smokers and 10.18% were former smokers. In terms of obesity classification, 4.19% of individuals were classified as Grade 1 obese; 53.29% as Grade 2 obese, and 42.51% as Grade 3 obese.
Regarding length of hospital stay, we observed a significant reduction in the groups studied, with the length of hospital stay being shorter in G2 (p<0.050), as shown in Table 1.
Regarding oxygen saturation (SpO2) and respiratory rate (RR), there was no statistical difference between groups. However, a decrease in SpO₂ was observed in the immediate postoperative period compared to the preoperative period, followed by an increase in values when comparing the immediate postoperative period with the first and second postoperative periods in groups G4 and G2 (p<0.05). The same variation was observed for respiratory rate, which decreased in the immediate postoperative period, followed by an increase in the first and second postoperative periods. Despite the increase in RR, values remained within the physiological range (Table 2).
When analyzing heart rate (HR) and mean arterial pressure (MAP), we observed statistical differences (p<0.05) between groups and time points. There was a reduction in mean arterial pressure over time across all groups (p<0.05). For HR, an increase occurred in the immediate postoperative period and first postoperative period in G6, while a decrease in HR was observed over time in groups G4 and G2. However, the magnitude of these differences was minimal relative to the variables scale, with vital signs remaining stable within normal limits.
When evaluating spirometry variables, a significant reduction in FEV1, FVC, MVV, FEF25-75%, and PEF values was observed in the immediate postoperative period. Notably, a gradual and significant increase (p≤0.05) with the progression of days (first and second postoperative days) was also observed, although these values did not return to baseline levels. When comparing the spirometry data between the studied groups in the preoperative, immediate postoperative, first and second postoperative periods, no significant differences were observed between groups G6, G4, and G2, as shown in Table 3.
DISCUSSION
The main findings of this study indicate that, when early mobilization was initiated two hours after bariatric surgery, there was greater recovery of lung capacity compared to patients who began the physical therapy protocol four and six hours after surgery.
This study observed a higher prevalence of female patients aged around 30 years, and BMI analysis indicated that most individuals had an average BMI of 39.9 kg/m2. Such data corroborates the epidemiological profile described by Araújo et al.10: patients undergoing bariatric surgery consisted of female patients aged 30 to 40 years with an average BMI of 45.10 kg/m2, classified as morbidly obese.
According to the study, 89.22% of patients did not have ventilatory disorders in the preoperative pulmonary function test. It can be explained by the predominance of grade II obesity in patients (53.29%). This differs from the study by Paisani et al.11 evaluating patients with a mean BMI of 50.4 kg/m2 and observing a higher incidence of ventilatory disorders. Moreover, 79.04% of patients in our study had never smoked, which may be related to the results obtained from the preoperative pulmonary function test.
In a systematic review, Malczak et al.12 demonstrated that the early recovery protocol in bariatric surgery is safe in postoperative care, favoring a reduction in hospitalization time and a tendency toward fewer readmissions, corroborating our study, in which the hospitalization rate was reduced with the application of early mobilization two hours after surgery.
In this study, monitoring of respiratory and hemodynamic variables demonstrated that the postoperative physical therapy protocol was performed safely, as heart and respiratory rate, mean arterial pressure, and peripheral oxygen saturation parameters remained at physiological levels throughout the days analyzed. Similarly, Svensson-Raskh et al.13 found that moving patients out of bed within two hours after abdominal surgery was feasible and there were no adverse consequences related to the intervention. In addition, the authors observed that mobilization out of bed, with or without breathing exercises, within two hours after elective abdominal surgery improved pulmonary gas exchange as identified in the parameters.
We observed that oxygen saturation remained at physiological levels during all evaluations of all groups. Similarly, Duymaz et al.6 detected that postoperative respiratory physical therapy applied to patients undergoing bariatric surgery led to improved respiratory function, regulation of pulmonary gas exchange, increased oxygen saturation, improved functional capacity and quality of life, and decreased levels of dyspnea.
The patients in the study had higher values preoperatively than immediately postoperatively, when they showed a decline in pulmonary function values. However, an improvement in lung volumes and capacities was observed from the first postoperative day onwards. This may be due to the effects of anesthesia and analgesics in the immediate postoperative period, and further studies are needed for analysis. According to the review by Delgado and Lunardi14, changes in respiratory function can be observed in patients with obesity in the postoperative period of bariatric surgery, as evidenced by spirometry, mainly a reduction in vital capacity.
In this study, patients in all groups underwent daily physical therapy, starting at different times, and all three groups improved (intragroup comparison), corroborating the current literature that highlights the importance of physical therapy interventions in patients undergoing bariatric surgery. According to studies by Manzano et al.15 and Duymaz et al.6, physical therapy interventions have benefits for the recovery of respiratory function in the postoperative period of upper abdominal surgeries. Thus, maneuvers such as sustained maximum inspiration breathing exercises, chest expansion exercises, use of incentive spirometry, diaphragmatic mobilization, and early mobilization are often used for therapeutic purposes.
CONCLUSION
This study found that the physical therapy protocol of early mobilization started two, four, or six hours after surgery was safe regarding hemodynamic stability and effective in reducing hospital stay and improving lung function over time in patients who had bariatric surgery. However, early mobilization did not change lung function.
REFERENCES
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1
Approved by the Research Ethics Committee of the University of Campinas [Protocol No. 5,302,567 - RBR-5cmtnk].
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Financing source:
nothing to declare.
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5
Study conducted at the Universidade Federal de Alfenas (UNIFAL) - Alfenas (MG), Brazil and at the Hospital e Maternidade Galileo - Valinhos (SP), Brazil.
Publication Dates
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Publication in this collection
18 Aug 2025 -
Date of issue
2025
History
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Received
26 Mar 2024 -
Accepted
14 Oct 2024
