Influence of working shift on the formation of lower limb edema in normal individuals

Abstracts

CONTEXTO: A presença de edema vespertino nos membros inferiores de indivíduos normais, após jornada habitual de trabalho, foi demonstrada na literatura nacional e internacional. O ritmo de formação e o acúmulo desse edema variam de acordo com os distintos turnos laborais. OBJETIVO: O edema de membros inferiores tem sido descrito após jornadas habituais de trabalho e representa uma queixa freqüente na prática vascular. O objetivo deste estudo foi avaliar a evolução do edema em indivíduos normais durante os distintos turnos laborais. MÉTODO: Foram feitas avaliações volumétricas de ambos os membros inferiores em 20 profissionais da área da saúde do Hospital e Maternidade São Marcos de Maringá, no Paraná. A escolha dos participantes foi por ordem de chegada, e as volumetrias foram feitas por técnica de deslocamento de água às 7, 13 e 19 h. Para análise estatística foi utilizado o teste t de Student, considerando erro alfa de 5%. RESULTADO: Dos 20 participantes, 19 eram do sexo feminino e 1 do masculino, sem evidência de doença venosa nos membros inferiores e pertencentes a C0 e C1 da classificação CEAP (C = clínica, E = etiologia, A = segmento anatômico, P = fisiopatologia). As idades dos participantes variaram entre 20 e 53 anos. Detectou-se aumento significativo de volume nos membros inferiores entre os distintos períodos avaliados, com p = 0,0001 e 0,0001, respectivamente. A maior variação ocorreu no período da manhã, com média ± desvio padrão de 107,2±63,5 mL, enquanto que à tarde, a variação foi de 44,5±35,4 mL. CONCLUSÃO: O edema é uma constante durante atividades laborais, mesmo em pessoas sem doença venosa manifesta e sofre influência do turno laboral ao qual o trabalhador se encontra exposto.

Edema; insuficiência venosa; fisiologia do trabalho; turno laboral

ORIGINAL ARTICLE

Influence of working shift on the formation of lower limb edema in normal individuals

Cleusa Ema Quilici Belczak^I; José Maria Pereira de Godoy^II; Rubiana Neves Ramos^III; Márcia Aparecida de Oliveira^III; Sergio Quilici Belczak^IV; Roberto Augusto Caffaro^V

^IPhD student in General Surgery, Faculdade de Ciências Médicas da Santa Casa de São Paulo (FCMSCSP), São Paulo, SP, Brazil. Professor, Graduation in Lymphovenous Rehabilitation, Faculdade de Medicina de São José do Rio Preto (FAMERP), São José do Rio Preto, SP, Brazil

^IIPhD in Cardiology and Cardiovascular Surgery. Professor, associate professor, Department of Surgery, FAMERP, São José do Rio Preto, SP, Brazil Researcher, National Counsel of Technological and Scientific Development (CNPq)

^IIIPhysical therapists, Centro Vascular João Belczak, Maringá, PR, Brazil

^IVResident in Vascular Surgery, Hospital das Clínicas da Universidade de São Paulo (HCUSP), São Paulo, SP, Brazil

^VPhD in Vascular Surgery. Associate professor, FCMSCSP, São Paulo, SP, Brazil

Correspondence

ABSTRACT

BACKGROUND: Presence of evening edema of lower limbs in normal individuals after a regular working shift has been shown in the national and international literature. Formation rhythm and accumulation of this type of edema vary according to different work shifts.

OBJECTIVE: Edema of the legs has been described after regular work shifts and is a common complaint in vascular practice. The objective of this study was to evaluate the evolution of edema in apparently normal individuals during distinct work shifts.

METHOD: Volumetric assessments of both legs were performed in 20 healthcare professionals at São Marcos Hospital and Maternidade in Maringá, Brazil. Individuals were selected on a consecutive basis with water displacement volumetry being performed at 7:00 a.m., 1:00 p.m. and 7:00 p.m. Student's t test was used for statistical analysis with an alpha error of 5% being considered acceptable.

RESULTS: The study group consisted of 19 women and one man with ages ranging from 20 to 53 years old. The participants had no evidence of venous diseases of the lower limbs and were C0 or C1 according to the CEAP classification (C = clinical, E = etiology, A = anatomy, P = pathophysiology). Significant increases in the volume of both legs were seen after both shifts (p = 0.0001 in both cases). The greatest variation occurred during the morning with a mean ± standard deviation of 107.2±63.5 mL, while in the afternoon mean increase was 44.5±35.4 mL.

CONCLUSION: Edema is constant in work activities, even in individuals without obvious venous diseases, and is influenced by work shift.

Keywords: Edema, venous insufficiency, physiology of work, work shift.

Introduction

In normal individuals, presence of lower limb edema after a usual working shift has been detected and evaluated in some studies.^1,2 Edema formation and prevention using elastic stockings have also been shown.² Other researchers have detected several volumetric variations in the lower limbs along a working day in healthy patients, whose numbers were different between dominant and non-dominant limbs and are influenced by use of drugs, such as calcium channel blockers.^3-5

It is known that there is a venous hemodynamic variation throughout the day as a consequence of valve cusp separation, which causes an increase in venous reflux.⁶ Circadian rhythm is known as part of the human physiology in many systems, whether they are influenced or not by posture or variations in blood biochemistry, such as in the case of estrogen levels acting on smooth muscle cells.^7-9

Lower limb edema is considered to be the most important factor in quality of life, as it causes great discomfort, early fatigue and feeling of weight, which certainly reduces professional performance.¹⁰ Such clinical manifestations almost always represent a first manifestation of venous system decompensation, whose severe complication culminates with occurrence of chronic venous insufficiency (CVI) of the lower limbs, a disease to be prevented as it represents the 14th cause of absenteeism at work, resulting in embarrassment and economic impairment for the individual and the society.¹¹

This justifies not only research on the etiopathogenic characteristics of the edema but also the quantification of its magnitude to support studies of efficacious prophylactic methods to prevent morbid evolution of CVI and to interpret its clinical expression as to the working shift to which the individual is exposed.

This study aims at detecting presence of edema in normal individuals, accumulated throughout a working shift, and evaluating its evolution during different work shifts.

Method

Volumetric evaluations of the lower limbs were performed in 20 health professionals of Hospital e Maternidade São Marcos de Maringá, in Paraná, Brazil, from December 10, 2007 to January 20, 2008. Nineteen women and one man were evaluated, with ages ranging from 20 to 53 years, including nurses, janitors, receptionists, kitchen maids, and assistants in the surgical center. The participants' work activities intercalated periods of static and dynamic upright and sitting position, similarly to time proportion. The selection was performed by invitations, consecutively based on hospital admittance, excluding employees that remained standing or sitting for prolonged time through the whole working period. The participants were recruited when they were on 12-hour duty. Each individual was assessed before starting their work shift, at 7 a.m., after the morning shift, at 1 p.m., and at the end of the work shift, at 7 p.m., after 12 hours of work, in a total of 120 measurements in 40 assessed limbs.

Volumetry was performed using the technique of water displacement by the lower limbs (feet and legs). All the participants were part of the same urban population group and signed a consent term after being informed about the objective of this study, which was previously approved by the Ethics Committee of the Centro Universitário de Maringá (PR).

To avoid inclusion of people with CVI in the lower limbs in the sample (a factor that could interfere with quantity of accumulated edema volume in the lower limbs), only participants with limbs classified as C0 an C1 according to the CEAP classification of the International Consensus Committee on Venous Disease (in which C = clinical, E = etiologic, A = anatomic and P = pathophysiologic) were included. C0 means absence of signs and symptoms of venous insufficiency, and C1 refers to presence of telangiectasias.^12-14 Anamnesis and clinical examination of selected individuals were performed by a vascular physician of the hospital.

Exclusion criteria were also ischemic, hypertensive and diabetic patients and/or those under use of drugs, such as diuretics and hormones, which could also influence formation of edema, in addition to individuals with systemic lower limb edema, such as congestive heart, renal and liver failure, myxedema and traumatic or rheumatic joint diseases. Individuals who had lymphedema or that routinely used elastic stockings or that had any type of dermatologic lesion were also excluded.

Volumetric measures were performed by the same physical therapist, using glass water tanks at room temperature, built for this purpose. The tanks had two outputs: one for initial water leveling and another for the output of displaced water. Liquid volume equivalent to the distance between both outputs was previously evaluated, allowing perfect stabilization of the liquid level before and during the examination. The volume of the immersed limb is equivalent to the volume of displaced water upward plus the volume of water entering the graduated recipient, where exceeding millimeters are measured in absolute numbers (Figure 1).¹

Results

Table 1 shows the volumetric variations of the limbs throughout the day.

Table 2 shows the means, standard deviation, minimal and maximal values, median and p of Student's ttest.

Discussion

This study shows the volumetric variations of the lower limbs in individuals without apparent venous disease, in whom the edema is constant throughout the day. It is more significant in the first work shift, i.e., in the morning, as can be seen in Table 2. Water displacement volumetry was chosen to measure formation of edema, as it is a safe and low cost method that can be repeated, in addition to being easily performed and is still considered as the gold standard for this type of measurement.^15-18

Although the edema is associated with many systemic diseases and local causes that in our sample were exclusion criteria, this study warns to the fact that it is present in apparently healthy workers. In the surveyed literature, it was shown that the edema is also due to the posture adopted during a work shift.¹⁴ It is known that volumetric changes during the whole daily activity have prolonged standing position as the main aggravating factor. Therefore, this study included only individuals of similar work activity, as previously described, and those who maintained a static position for long periods, such as surgeons, surgical technologists and executive secretaries, due to the possibility of interference with obtained results.

Irrespective of origin or etiopathology, it is important to evaluate the quantity of edema in the lower limb in clinical practice before and after the individual ends his work shift, as well as investigate whether the shift in which the individual perform his activity interferes with the amount of edema. It is common to find individuals with symptoms suggesting CVI without established venous and lymphatic disease. It is believed that the rhythm of volumetric variation in the limb, throughout the day, could justify such symptoms. In these cases, volumetry could be suggested and, in case of changes, prophylactic measures could be prescribed (for example, interval with rest in the horizontal position, during the work period, to lower venous pressure and/or proper use of elastic stockings).

Our measurements were evaluated at a single seasonal period; it is known that the edema is sensitive not only to posture changes, but also to temperature.¹⁶ Vayssairat et al.,¹⁹ in 1994, using volumetry to measure normal volunteers, as in our study, and patients with varicose veins, observed that there was a significant difference between morning and afternoon measures in normal legs. This fact could corroborate change in venous hemodynamics detected by many authors in normal limbs during everyday work activity, and there is a full agreement as to the influence of prolonged standing position, reduced walking or sitting position for long periods.^6,9,20

Another important aspect to be considered is capillary permeability, as it can cause major changes in the limb volume of sedentary individuals. Differently from plasma volume, whose control is performed based on baroreceptors in the arterial territory and volume receptors in low pressure territories, control of interstitial flow is performed by means of local physical forces.²¹ It is necessary to consider the levels of fluid filtration and reabsorption in the tissues, whose unbalance is the genesis of venous and lymphatic diseases. When the edema factor is under investigation, it is relevant to remember the balance between hydrostatic and colloidosmotic pressures of the interstitium and plasma described by Starling in 1896 (apud Szuba et al.²²).

During sleep, i.e., in the supine position maintained by hours in night rest, reduction in gravitational pressure allows the limb to be emptied, that is, return to normal and stabilize the pressures at a microcirculatory level, balancing intra- and extravascular. It is supposed that in the morning, once the edema of the previous day is absorbed, the interstitial pressure is likely to be quite low, facilitating capillary filtration, which explains greater formation of edema in the morning shift seen in this study, with mean edema accumulation of 107.2 mL in this period. During the afternoon, due to increase in interstitial pressure resulting from a high filtration in the morning, there might be a compensatory response, causing greater reabsorption into the intravascular, which justifies, in pressure levels, the smaller formation of edema in the second shift, a fact that was also observed in our sample, whose mean edema accumulation in this period was 44.5 mL. Thus, it can be imagined that, early in the morning, when the edema is not swollen, it behaves as an empty sponge, and that, by noon, when it is partially filled, it will prevent formation of the same amount of edema, explaining the significant values found in this study.

It can be stated that the volume of accumulated edema in the morning is higher than in the afternoon due to a change in the balance of pressures caused by limitation of capillary filtration in the second shift, producing a deceleration of lymphovenous drainage.

Conclusion

It is concluded that the edema is constant during work activities even in individuals without manifested venous disease, and that it is influenced by the work shift to which the worker is exposed.

References

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Publication Dates

• Publication in this collection
  08 Dec 2008
• Date of issue
  Sept 2008

History

• Accepted
  24 June 2008
• Received
  03 May 2008