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Adverse lighting condition effects on the assessment of capillary refill
Adverse Lighting Condition Effects on the Assessment of Capillary Refill LAWRENCE H. BROWN, EMT-P,* N. HERAMBA THEODORE W. WHITLEY, PtiD-f In 1969, Champion et al’ recommended revising the Trauma Score to exclude capillary refill because it is “difficult to assess at night. . . .‘I However, a literature search produced no studies evaluating the effecl of lighting conditions on the assessment of capillary refill. This study was undertaken to determine if any such effect exists. Three hundred nine participants at an emergency medical services (EMS) seminar were asked to assess each others’ capillary refill in both light and dark environments. The participants were nurses, emergency medical technicians (EMTs), and paramedics who had been instructed in the assessment of capillary refill. In daylight conditions (partly cloudy day, lux meter = 15 to 16), capillary refill was repotted as normal in 94.2% of the participants, delayed in 1.9% of the participants, and undetected in 3.9% of the participants. In dark conditions (moonlight or street lamp, lux meter = 4 to 6), capillary refill was reported as normal in 31.7% of the participants, delayed in 1.6% of the participants, and undetected in 66.7% of the participants. x2 analysis demonstrated a statistically significant difference between capillary refill assessment in light versus dark environments (P < .OOl). (Am J Emerg Med 1994;12:46-47. Copyright 0 1994 by W.6. Saunders Company)
Recent studies have questioned the correlation between delayed capillary refill and central circulation.‘-’ In addition to discussing the variation in capillary refill among specific subject groups and the appropriate location to assess capillary refill,’ some of these studies have asserted that adverse lighting conditions affect the assessment of capillary refill, particularly in the prehospital setting. ‘.4.5 Although the Revised Trauma Score has excluded capillary refill based on this concern,’ a literature search produced no studies evaluating the effect of lighting conditions on the ability to assess capillary refill. Therefore, this study was undertaken to determine the effect adverse lighting conditions have on the assessment of capillary refill. METHODS The study was conducted during a general session at a statewide emergency medical services (EMS) conference. Institutional review board approval was not required for this study. Three hundred nine EMS providers attending the conference voluntarily participated as subjects. All of the participants were nurses, emergency medical technicians (EMTs), or paramedics. Fifty-one percent of the partic-
From the *Division of Emergency Medical Services, Department of Emergency Medicine,tCenter for Medical Education, East Carolina University School of Medicine, Greenville, NC. Manuscript received April 23, 1993; revision accepted June 25, 1993. Address reprint requests to Mr Brown, EMT-P, Division of Emergency Medical Services, Department of Emergency Medicine, East Carolina University School of Medicine, Building M, Physicians’ Quadrangle, Greenville, NC 27858. Key Words: Assessment, capillary refill, circulation, shock. Copyright 0 1994 by W.B. Saunders Company 0735-6757/94/l 201-0010$5.00/O 46
PRASAD, MD,*
ipants were women and 49% were men. Ages ranged from I5 to 70 years of age (mean age, 36.6 ? 10.7 years). A Gossen Lunapro lux meter (Gossen, a Division of Berkey Marketing Companies, Greenwich, CT) was used to establish lighting conditions. Light levels were measured outside in bright sunshine. partial cloud cover, at dusk, and in darkness. The auditorium lights were adjusted to simulate lighting conditions. At their brightest level, the lights produced a lux meter reading of 15 to 16. slightly less than the reading of 18 obtained for a partly cloudy afternoon. A lux meter reading of 4 to 6 was comparable to standing outside on a bright, moonlit night, or within 50 ft of a street lamp at night. Participants were asked to assess each others’ capillary refill in both light and dark environments using the pulp of the index finger. A pilot study showed that capillary refill should be assessed in the finger pulp to avoid any problems with nail polish. Before the trials, one of the authors reviewed and demonstrated the procedure for assessing capillary refill. Because the auditorium had already been darkened for approximately 30 minutes for the preceding presentation. assessment in the dark environment was performed first. The participants blanched each others’ capillary bed, the moderator of the session said “go.” and the participants assessed each others’ capillary refill. After 2 seconds, the auditorium lights were turned completely off, creating total darkness and thus limiting the assessment to 2 seconds. The participants then recorded the capillary refill as normal, delayed, or not detected on a data collection card. The auditorium lights were then set at a their brightest level, and the process was repeated. x’ analysis using a 2 x 3 x’ was performed to detect differences in capillary refill assessment under each of the lighting conditions. An u level of ,001 was used to determine statistical significance.
RESULTS Table 1 shows the results of the capillary refill assessments for each lighting condition. Capillary refill in daylight (lux meter = I5 to 16) conditions was reported as normal for 291 (94.2%) of the participants and not detected in 12 (3.9%) of the participants. Capillary refill in dark (lux meter = 4 to 6) conditions was reported as normal for 98 (31.7%) of the participants and not detected in 206 (66.7%) of the participants. The x’ analysis showed significant differences in capillary refill assessment for each lighting condition (P < .OOI). Our analysis did not show any trends or variations in capillary refill assessment attributable to age and/or sex. DISCUSSION
Previous studies have addressed the accuracy and reliability of capillary refill as an indicator of perfusion. Schriger and Baraff examined the normal limits of capillary refill and suggested that the limits should be modified to correlate with age and sex.’ In a later study, the same authors were unable to demonstrate a relationship between capillary refill and 450 mL blood loss, hypotension, or hypovolemia. These authors
BROWN ET AL n LIGHTING
TABLE1.
Capillary Environments
Refill Assessment
Light Normal Delayed Undetected
CONDITIONS
Environment
291 (94.2%) 6 (1.9%) 12 (3.9%)
AND CAPILLARY
REFILL
in Both Light and Dark
Dark Environment 98 (31.7%) 5 (1.6%) 206 (66.7%)
concede that their study used clinical findings and history to determine the subjects’ hemodynamic status. They suggest that direct measurement of cardiac output would have been a better contro1.4 A study that used pulmonary artery catheters to determine central circulation also found no relationship between capillary refill and circulatory status on the day of coronary artery bypass graft surgery. These patients, however, were likely to be hypothermic on admission to the intensive care unit.3 Low body temperature, low skin temperature, and ambient room temperature have been shown to affect capillary refill.‘.‘.” In 1989, Champion et al recommended revising the Trauma Score to exclude capillary refill because “field use . . has revealed that capillary refill . . . [is] difficult to assess at night. . . .“I None of the studies cite clinical trials to support their assertions that capillary refill is difficult to assess in poor lighting conditions. This study demonstrates that lighting conditions are likely to affect the assessment of capillary refill. Capillary refill could not be assessed in more than two thirds of the study participants in the dark environment. Many EMS scenes involve dark rooms or roadsides, however, flashlights and floodlights are likely to provide enough light to permit the assessment of capillary refill. Follow-up studies should be conducted to validate capillary refill assessment using these lighting sources. This study presumes that the circulatory status of the subjects did not change significantly during the course of the study, which was approximately 15 minutes. Also, this study does not address the effect of environmental factors, such as temperature or dirty hands, on the assessment of capillary refill. Nor does the study resolve questions about the specificity or sensitivity of capillary refill as a test.
47
Currently, capillary refill remains in emergency care curricula as a method of assessing circulation.‘,’ Even if further studies diminish the use of capillary refill in assessing central circulation, it will still be used in the assessment of circulation distal to extremity injuries.‘,” As long as capillary refill is used in the evaluation of emergency patients, it is important to recognize factors that may affect assessment. It is most important to remember that patient care decisions should be based on the entire physical assessment and not just one finding.’ In addressing concerns about capillary refill, decisions on its use should be based on practical experience and on current and future studies of the efficacy of the test. Concerns about the ability to assess capillary refill in uncontrolled lighting conditions appear to have some merit, and should be considered when using capillary refill to assess circulatory status. REFERENCES 1. Champion HR, Sacco WJ, Copes WS, et al: A revision of the Trauma Score. J Trauma 1989;29:623-629 2. Schriger DL, Baraff L: Defining normal capillary refill: Variation with age, sex, and temperature. Ann Emerg Med 1988; 17:932-935 3. Bailey JM, Levy JH, Kopel MA, et al: Relationship between clinical evaluation of peripheral perfusion and global hemodynamics in adults after cardiac surgery. Critical Care Medicine 1990;18:1353-1356 4. Schriger DL, Baraff LJ: Capillary refillls it a useful predictor of hypovolemic states? Ann Emerg Med 1991;20:601-605 5. Knopp RK: Capillary refill: New concerns about an old bedside test. Ann Emerg Med 1988;17:990-991 (editorial) 6. Stoner HB, Barker P, Riding GSG, et al: Relationships between skin temperature and perfusion in the arm and leg. Clinical Physiology 1991 ;11:27-40 7. Bledsoe BE, Porter RS, Shade BR: Paramedic Emergency Care, ed 1. Englewood Cliffs, NJ, Prentice-Hall, 1991, pp 161-162 8. Fowler RL: Shock, In Campbell JE (ed): Basic Trauma Life Support Advanced Prehospital Care, ed 2. Englewood Cliffs, NJ, Prentice Hall Inc. 1988 pp 107-118 9. Applebaum R, Yellin AE, Weaver FA, et al: Role of routine arteriography in blunt lower extremity trauma. Am J Surgery 1990;160:221-224 10. Weaver FA, Yellin AE, Bauer M, et al: Is arterial proximity a valid indication for arteriography in penetrating extremity trauma? Arch Surg 1990;125:1256-1260
Recent studies have questioned the correlation between delayed capillary refill and central circulation.‘-’ In addition to discussing the variation in capillary refill among specific subject groups and the appropriate location to assess capillary refill,’ some of these studies have asserted that adverse lighting conditions affect the assessment of capillary refill, particularly in the prehospital setting. ‘.4.5 Although the Revised Trauma Score has excluded capillary refill based on this concern,’ a literature search produced no studies evaluating the effect of lighting conditions on the ability to assess capillary refill. Therefore, this study was undertaken to determine the effect adverse lighting conditions have on the assessment of capillary refill. METHODS The study was conducted during a general session at a statewide emergency medical services (EMS) conference. Institutional review board approval was not required for this study. Three hundred nine EMS providers attending the conference voluntarily participated as subjects. All of the participants were nurses, emergency medical technicians (EMTs), or paramedics. Fifty-one percent of the partic-
From the *Division of Emergency Medical Services, Department of Emergency Medicine,tCenter for Medical Education, East Carolina University School of Medicine, Greenville, NC. Manuscript received April 23, 1993; revision accepted June 25, 1993. Address reprint requests to Mr Brown, EMT-P, Division of Emergency Medical Services, Department of Emergency Medicine, East Carolina University School of Medicine, Building M, Physicians’ Quadrangle, Greenville, NC 27858. Key Words: Assessment, capillary refill, circulation, shock. Copyright 0 1994 by W.B. Saunders Company 0735-6757/94/l 201-0010$5.00/O 46
PRASAD, MD,*
ipants were women and 49% were men. Ages ranged from I5 to 70 years of age (mean age, 36.6 ? 10.7 years). A Gossen Lunapro lux meter (Gossen, a Division of Berkey Marketing Companies, Greenwich, CT) was used to establish lighting conditions. Light levels were measured outside in bright sunshine. partial cloud cover, at dusk, and in darkness. The auditorium lights were adjusted to simulate lighting conditions. At their brightest level, the lights produced a lux meter reading of 15 to 16. slightly less than the reading of 18 obtained for a partly cloudy afternoon. A lux meter reading of 4 to 6 was comparable to standing outside on a bright, moonlit night, or within 50 ft of a street lamp at night. Participants were asked to assess each others’ capillary refill in both light and dark environments using the pulp of the index finger. A pilot study showed that capillary refill should be assessed in the finger pulp to avoid any problems with nail polish. Before the trials, one of the authors reviewed and demonstrated the procedure for assessing capillary refill. Because the auditorium had already been darkened for approximately 30 minutes for the preceding presentation. assessment in the dark environment was performed first. The participants blanched each others’ capillary bed, the moderator of the session said “go.” and the participants assessed each others’ capillary refill. After 2 seconds, the auditorium lights were turned completely off, creating total darkness and thus limiting the assessment to 2 seconds. The participants then recorded the capillary refill as normal, delayed, or not detected on a data collection card. The auditorium lights were then set at a their brightest level, and the process was repeated. x’ analysis using a 2 x 3 x’ was performed to detect differences in capillary refill assessment under each of the lighting conditions. An u level of ,001 was used to determine statistical significance.
RESULTS Table 1 shows the results of the capillary refill assessments for each lighting condition. Capillary refill in daylight (lux meter = I5 to 16) conditions was reported as normal for 291 (94.2%) of the participants and not detected in 12 (3.9%) of the participants. Capillary refill in dark (lux meter = 4 to 6) conditions was reported as normal for 98 (31.7%) of the participants and not detected in 206 (66.7%) of the participants. The x’ analysis showed significant differences in capillary refill assessment for each lighting condition (P < .OOI). Our analysis did not show any trends or variations in capillary refill assessment attributable to age and/or sex. DISCUSSION
Previous studies have addressed the accuracy and reliability of capillary refill as an indicator of perfusion. Schriger and Baraff examined the normal limits of capillary refill and suggested that the limits should be modified to correlate with age and sex.’ In a later study, the same authors were unable to demonstrate a relationship between capillary refill and 450 mL blood loss, hypotension, or hypovolemia. These authors
BROWN ET AL n LIGHTING
TABLE1.
Capillary Environments
Refill Assessment
Light Normal Delayed Undetected
CONDITIONS
Environment
291 (94.2%) 6 (1.9%) 12 (3.9%)
AND CAPILLARY
REFILL
in Both Light and Dark
Dark Environment 98 (31.7%) 5 (1.6%) 206 (66.7%)
concede that their study used clinical findings and history to determine the subjects’ hemodynamic status. They suggest that direct measurement of cardiac output would have been a better contro1.4 A study that used pulmonary artery catheters to determine central circulation also found no relationship between capillary refill and circulatory status on the day of coronary artery bypass graft surgery. These patients, however, were likely to be hypothermic on admission to the intensive care unit.3 Low body temperature, low skin temperature, and ambient room temperature have been shown to affect capillary refill.‘.‘.” In 1989, Champion et al recommended revising the Trauma Score to exclude capillary refill because “field use . . has revealed that capillary refill . . . [is] difficult to assess at night. . . .“I None of the studies cite clinical trials to support their assertions that capillary refill is difficult to assess in poor lighting conditions. This study demonstrates that lighting conditions are likely to affect the assessment of capillary refill. Capillary refill could not be assessed in more than two thirds of the study participants in the dark environment. Many EMS scenes involve dark rooms or roadsides, however, flashlights and floodlights are likely to provide enough light to permit the assessment of capillary refill. Follow-up studies should be conducted to validate capillary refill assessment using these lighting sources. This study presumes that the circulatory status of the subjects did not change significantly during the course of the study, which was approximately 15 minutes. Also, this study does not address the effect of environmental factors, such as temperature or dirty hands, on the assessment of capillary refill. Nor does the study resolve questions about the specificity or sensitivity of capillary refill as a test.
47
Currently, capillary refill remains in emergency care curricula as a method of assessing circulation.‘,’ Even if further studies diminish the use of capillary refill in assessing central circulation, it will still be used in the assessment of circulation distal to extremity injuries.‘,” As long as capillary refill is used in the evaluation of emergency patients, it is important to recognize factors that may affect assessment. It is most important to remember that patient care decisions should be based on the entire physical assessment and not just one finding.’ In addressing concerns about capillary refill, decisions on its use should be based on practical experience and on current and future studies of the efficacy of the test. Concerns about the ability to assess capillary refill in uncontrolled lighting conditions appear to have some merit, and should be considered when using capillary refill to assess circulatory status. REFERENCES 1. Champion HR, Sacco WJ, Copes WS, et al: A revision of the Trauma Score. J Trauma 1989;29:623-629 2. Schriger DL, Baraff L: Defining normal capillary refill: Variation with age, sex, and temperature. Ann Emerg Med 1988; 17:932-935 3. Bailey JM, Levy JH, Kopel MA, et al: Relationship between clinical evaluation of peripheral perfusion and global hemodynamics in adults after cardiac surgery. Critical Care Medicine 1990;18:1353-1356 4. Schriger DL, Baraff LJ: Capillary refillls it a useful predictor of hypovolemic states? Ann Emerg Med 1991;20:601-605 5. Knopp RK: Capillary refill: New concerns about an old bedside test. Ann Emerg Med 1988;17:990-991 (editorial) 6. Stoner HB, Barker P, Riding GSG, et al: Relationships between skin temperature and perfusion in the arm and leg. Clinical Physiology 1991 ;11:27-40 7. Bledsoe BE, Porter RS, Shade BR: Paramedic Emergency Care, ed 1. Englewood Cliffs, NJ, Prentice-Hall, 1991, pp 161-162 8. Fowler RL: Shock, In Campbell JE (ed): Basic Trauma Life Support Advanced Prehospital Care, ed 2. Englewood Cliffs, NJ, Prentice Hall Inc. 1988 pp 107-118 9. Applebaum R, Yellin AE, Weaver FA, et al: Role of routine arteriography in blunt lower extremity trauma. Am J Surgery 1990;160:221-224 10. Weaver FA, Yellin AE, Bauer M, et al: Is arterial proximity a valid indication for arteriography in penetrating extremity trauma? Arch Surg 1990;125:1256-1260