UROLOGY ANZJSurg.com
Accuracy of surgical wound drainage measurements: an analysis and comparison Brian Yue,* Danielle Nizzero,† Chunxiao Zhang,† Natasha van Zyl* and Jeannette Ting† *Plastic and Reconstructive Surgery, Royal Melbourne Hospital, Melbourne, Victoria, Australia and †Plastic and Reconstructive Surgery, Austin Hospital, Melbourne, Victoria, Australia
Key words drain, post-operative, reading, reliability, suction. Correspondence Dr Brian Yue, Plastic and Reconstructive Surgery, Royal Melbourne Hospital, 300 Grattan Street, Melbourne, Vic. 3053, Australia. Email: [email protected] B. Yue MBBS, Dip Anat; D. Nizzero MBBS, Dip Anat; C. Zhang MBBS; N. van Zyl, MBChB (Cape Town), FRACS; J. Ting MBBS, MS. Accepted for publication 6 February 2014. doi: 10.1111/ans.12657
Abstract Background: Surgical drain tube readings can influence the clinical management of the post-operative patient. The accuracy of these readings has not been documented in the current literature and this experimental study aims to address this paucity. Methods: Aliquots (10, 25, 40 and 90 mL) of black tea solution prepared to mimic haemoserous fluid were injected into UnoVac, RedoVac and Jackson-Pratt drain tubes. Nursing and medical staff from a tertiary hospital were asked to estimate drain volumes by direct observation; analysis of variance was performed on the results and significance level was set at 0.05. Results: Doctors and nurses are equally accurate in estimating drain tube volumes. Jackson-Pratt systems were found to be the most accurate for intermediate volumes of 25 and 40 mL. For extreme of volumes (both high and low), all drainage systems were inaccurate. Conclusion: This study suggests that for intermediate volumes (25 and 40 mL), Jackson-Pratt is the drainage system of choice. The accuracy of volume measurement is diminished at the extremes of drain volumes; emptying of drainage systems is recommended to avoid overfilling of drainage systems.
Introduction
Methods
Surgical wound drainage is an integral part of modern surgical practice used mainly to drain collections in the post-operative wound bed that may develop. The use of drain tubes has also been shown to decrease wound complications.1–3 Conversely, most authors do not advocate leaving drain tubes in situ for extended periods of time due to risk of retrograde bacterial contamination.4,5 A widely accepted method of determining the optimal time to remove drain tubes is measurement of the volume of wound drainage over a period of time, usually 24 h.3,6–8 Accurate drain tube readings can therefore influence the clinical outcome of the postoperative patient including days of hospital stay, outsourcing of nursing care post discharge and risks of infection and seroma formation. To date, there have been no published studies to investigate the accuracy of surgical wound drainage system volume readings. This study aims to address this paucity by quantifying and comparing the accuracy of drainage volume readings in three common systems by hospital staff.
Study design
© 2014 Royal Australasian College of Surgeons
This study was conducted at a tertiary teaching hospital in Melbourne, Australia. A solution was prepared by mixing 100 g of Lipton Black Tea (Unilever, Surrey, UK) leaves in 1000 mL of boiling water to mimic the colour and concentration of haemoserous fluid. The solution was subsequently cooled to room temperature and filtered. Aliquots of 10, 25, 40 and 90 mL were then carefully prepared with syringes and the volumes validated by two independent experimenters. Each aliquot was introduced into three commonly used drainage systems: UnoVac 600 mL (Unomedical, Birkerød, Denmark) (Fig. 1), RedoVac 600 mL (PFM Medical, Köln, Germany) (Fig. 2) and Jackson-Pratt 100 mL (Cardinal Health, Dublin, OH, USA) (Fig. 3), producing a total of 12 testing samples. These samples were randomly presented to consenting nursing (n = 36) and medical (n = 29) staff in the surgical ward, who then estimated the drain volumes by direct observation of the fluid levels’ proximity to the volume gradients of each drainage system. The results were recorded by an independent observer. ANZ J Surg 85 (2015) 327–329
328
Fig. 1. UnoVac drainage system containing black tea solution mimicking haemoserous fluid.
Yue et al.
Fig. 4. Modified bar and whisker graph demonstrating the absolute difference between measurements from hospital staff and actual volume at 10, 25, 40 and 90 mL. Whiskers represent 95% confidence interval.
of observer (nurses or doctors). The accuracy of the reading is expressed as the absolute difference between observed and actual volumes unless otherwise stated. The significance level for the study was set at 0.05, with Bonferroni (post hoc) correction applied to all significant pairwise comparisons.
Results Fig. 2. RedoVac drainage system containing black tea solution mimicking haemoserous fluid.
Comparison between drainage systems For moderate-to-high volumes (≥25 mL) the volume of fluid in the Jackson-Pratt system was generally more accurately estimated when compared with UnoVac and RedoVac. At low volumes (10 mL) there was no difference in the accuracy of volume reading between the drain systems (Fig. 4).
Comparison between drainage volumes Drainage systems were in general less accurate at high volumes (90 mL) than at low volumes (10 mL) (P < 0.0001).
Comparison between nursing staff and doctors No significant difference in accuracy was identified between nurses and doctors. Fig. 3. Jackson-Pratt drainage system containing black tea solution mimicking haemoserous fluid.
Statistical analysis In order to analyse and compare the accuracy of readings between different drainage systems, different drainage volumes and different hospital staff (nursing versus medical), a three-way analysis of variance with repeated measures was performed. The three independent variables were the type of drain system (UnoVac, RedoVac and Jackson-Pratt), the drain volume (10, 25, 40 and 90 mL) and the type
Discussion Appropriate use of wound drainage has been documented to decrease post-operative wound seroma and haematoma formation.1–3 For example, the use of suction drainage in breast surgery has been shown to decrease the incidence of seroma.2,9–12 In head and neck surgery, Perkins et al. found that use of surgical wound drains decreased the rate of seroma and haematoma formation in patients undergoing facelift surgery.13 Although there are benefits to surgical wound drainage, the risk of infection increases proportionately with the duration of drainage © 2014 Royal Australasian College of Surgeons
Accuracy of drainage systems
placement.5,14,15 To determine the optimal time to remove drain tubes, the measurement of wound drainage volume is used in many types of surgery.3,4,6–8 For example, post mastectomy management, most surgeons advocate removal of drains when the daily drainage falls below 30 mL regardless of the time elapsed post surgery.3,4,6–8 A higher incidence of seroma formation was observed post removal of drains when the 24-h drainage volume was >50 mL.6 It is therefore important for medical and nursing staff to estimate drainage system volumes accurately to ensure appropriate timing of drain tube removal. Measurements of volume amounts are generally performed by one of two methods: direct observation of the fluid in the drainage system or through emptying of the fluid into a measuring container. In clinical practice, it is often preferable to estimate the drainage volume via direct observation, as this reduces the likelihood that suction drainage systems will inadvertently be changed to an ‘off suction’ state and allows a fast measurement reading of volume in drain. UnoVac 600 mL (Fig. 1), RedoVac 600 mL (Fig. 2) and JacksonPratt 100 mL (Fig. 3) were selected for this study because they are the most commonly available drainage systems for surgical wounds in Australia. Among these systems, we recommend using the Jackson-Pratt drainage system as it was markedly more accurate than UnoVac and RedoVac for operations where drain tube volumes are the main determinant of drain tube removal, although the aberrant finding of increased accuracy of Jackson-Pratt drains may be attributed to its smaller size of 100 mL. To put this finding into clinical perspective, our study estimates that only 5% of nurses and 1% of doctors will report values more than 30 mL in Jackson-Pratt drainage systems filled with 25 mL of fluid; therefore, these drains are more likely to be removed at the appropriate time. On the other hand, 58% of nurses and 51% of doctors will report values more than 30 mL when the RedoVac drainage system is used. Consequently when a RedoVac drainage system is used, the drains are more likely to be kept in for longer than required. Furthermore, in a drainage system that is filled with 40 mL of fluid, 0% of doctors will report less than 30 mL using the JacksonPratt system; however, 9% of doctors will report less than 30 mL using the UnoVac system. This translates to premature removal of the UnoVac system drain tubes in approximately 10% of the cases if volume of less than 30 mL is used as a threshold for drain removal. This study found that doctors and nurses are equally proficient in estimating drain tubes. Some differences may be attributed to their familiarity with the type of drainage system being used. For example, nurses tend to be more accurate than doctors with the UnoVac system. Using the UnoVac drainage systems, doctors are more accurate than nurses for 10 mL of aliquots, but are less accurate for higher volumes. However, the reduced accuracy for 10-mL volumes in nurses using UnoVac compared with doctors may be explained by nurses tending to round down to 0 mL for low volumes in drains. This study demonstrated that the accuracy of volume measurement is diminished at the extremes of drain volumes. Accuracy is expected to be worse with greater drain volumes, given that the more volume there is, the greater the margin for error. The authors recommend emptying the drainage systems when volumes are esti© 2014 Royal Australasian College of Surgeons
329
mated to be greater than 90 mL to ensure continued accuracy of drain tube volume estimates. If emptying of drainage systems at high volumes is not possible, we recommend use of the Jackson-Pratt or UnoVac drainage systems as medical and nursing staff were more accurate with these drainage systems compared with the RedoVac system at volumes greater than 90 mL. The aberrant finding of reduced accuracy with 10-mL volumes may be explained by the fact that at very low volumes, accuracy may also be impeded by other factors, such as the tendency for observers to round down to zero, or the difficulty in visualizing the drain fluid when making an assessment.
Conclusion Doctors and nurses are equally proficient in estimating drain tubes. This study suggests that for moderate-to-high volumes (≥25 mL), Jackson-Pratt is the drainage system of choice. The accuracy of volume measurement is diminished at the extremes of drain volumes, emptying of drainage systems is recommended to avoid overfilling of drainage systems.
References 1. Liu CD, McFadden DW. Overnight closed suction drainage after axillary lymphadenectomy for breast cancer. Am. Surg. 1997; 63: 868–70. 2. Aitken DR, Hunsaker R, James AG. Prevention of seromas following mastectomy and axillary dissection. Surg. Gynecol. Obstet. 1984; 158: 327–30. 3. Scevola S, Youssef A, Kroll SS, Langstein H. Drains and seromas in TRAM flap breast reconstruction. Ann. Plast. Surg. 2002; 48: 511–4. 4. Williams J, Toews D, Prince M. Survey of the use of suction drains in head and neck surgery and analysis of their biomechanical properties. J. Otolaryngol. 2003; 32: 16–22. 5. Drinkwater CJ, Neil MJ. Optimal timing of wound drain removal following total joint arthroplasty. J. Arthroplasty 1995; 10: 185–9. 6. Yii M, Murphy C, Orr N. Early removal of drains and discharge of breast cancer surgery patients: a controlled prospective clinical trial. Ann. R. Coll. Surg. Engl. 1995; 77: 377–9. 7. Tarazi R, Esselstyn CB Jr, Kuivila T, Hardesty I. Early hospital discharge following mastectomy. Cleve. Clin. Q. 1984; 51: 579–84. 8. Cohen AM, Schaeffer N, Chen ZY, Wood WC. Early discharge after modified radical mastectomy. Am. J. Surg. 1986; 151: 465–6. 9. Morris AM. A controlled trial of closed wound suction. Br. J. Surg. 1973; 60: 357–9. 10. Cameron AE, Ebbs SR, Wylie F, Baum M. Suction drainage of the axilla: a prospective randomized trial. Br. J. Surg. 1988; 75: 1211. 11. Soon PS, Clark J, Magarey CJ. Seroma formation after axillary lymphadenectomy with and without the use of drains. Breast 2005; 14: 103–7. 12. Barton A, Blitz M, Callahan D, Yakimets W, Adams D, Dabbs K. Early removal of postmastectomy drains is not beneficial: results from a halted randomized controlled trial. Am. J. Surg. 2006; 191: 652–6. 13. Perkins SW, Williams JD, Macdonald K, Robinson EB. Prevention of seromas and hematomas after face-lift surgery with the use of postoperative vacuum drains. Arch. Otolaryngol. Head Neck. Surg. 1997; 123: 743–5. 14. Willett KM, Simmons CD, Bentley G. The effect of suction drains after total hip replacement. J. Bone Joint Surg. Br. 1988; 70: 607–10. 15. Simchen E, Rozin R, Wax Y. The Israeli Study of Surgical Infection of drains and the risk of wound infection in operations for hernia. Surg. Gynecol. Obstet. 1990; 170: 331–7.
Accuracy of surgical wound drainage measurements: an analysis and comparison Brian Yue,* Danielle Nizzero,† Chunxiao Zhang,† Natasha van Zyl* and Jeannette Ting† *Plastic and Reconstructive Surgery, Royal Melbourne Hospital, Melbourne, Victoria, Australia and †Plastic and Reconstructive Surgery, Austin Hospital, Melbourne, Victoria, Australia
Key words drain, post-operative, reading, reliability, suction. Correspondence Dr Brian Yue, Plastic and Reconstructive Surgery, Royal Melbourne Hospital, 300 Grattan Street, Melbourne, Vic. 3053, Australia. Email: [email protected] B. Yue MBBS, Dip Anat; D. Nizzero MBBS, Dip Anat; C. Zhang MBBS; N. van Zyl, MBChB (Cape Town), FRACS; J. Ting MBBS, MS. Accepted for publication 6 February 2014. doi: 10.1111/ans.12657
Abstract Background: Surgical drain tube readings can influence the clinical management of the post-operative patient. The accuracy of these readings has not been documented in the current literature and this experimental study aims to address this paucity. Methods: Aliquots (10, 25, 40 and 90 mL) of black tea solution prepared to mimic haemoserous fluid were injected into UnoVac, RedoVac and Jackson-Pratt drain tubes. Nursing and medical staff from a tertiary hospital were asked to estimate drain volumes by direct observation; analysis of variance was performed on the results and significance level was set at 0.05. Results: Doctors and nurses are equally accurate in estimating drain tube volumes. Jackson-Pratt systems were found to be the most accurate for intermediate volumes of 25 and 40 mL. For extreme of volumes (both high and low), all drainage systems were inaccurate. Conclusion: This study suggests that for intermediate volumes (25 and 40 mL), Jackson-Pratt is the drainage system of choice. The accuracy of volume measurement is diminished at the extremes of drain volumes; emptying of drainage systems is recommended to avoid overfilling of drainage systems.
Introduction
Methods
Surgical wound drainage is an integral part of modern surgical practice used mainly to drain collections in the post-operative wound bed that may develop. The use of drain tubes has also been shown to decrease wound complications.1–3 Conversely, most authors do not advocate leaving drain tubes in situ for extended periods of time due to risk of retrograde bacterial contamination.4,5 A widely accepted method of determining the optimal time to remove drain tubes is measurement of the volume of wound drainage over a period of time, usually 24 h.3,6–8 Accurate drain tube readings can therefore influence the clinical outcome of the postoperative patient including days of hospital stay, outsourcing of nursing care post discharge and risks of infection and seroma formation. To date, there have been no published studies to investigate the accuracy of surgical wound drainage system volume readings. This study aims to address this paucity by quantifying and comparing the accuracy of drainage volume readings in three common systems by hospital staff.
Study design
© 2014 Royal Australasian College of Surgeons
This study was conducted at a tertiary teaching hospital in Melbourne, Australia. A solution was prepared by mixing 100 g of Lipton Black Tea (Unilever, Surrey, UK) leaves in 1000 mL of boiling water to mimic the colour and concentration of haemoserous fluid. The solution was subsequently cooled to room temperature and filtered. Aliquots of 10, 25, 40 and 90 mL were then carefully prepared with syringes and the volumes validated by two independent experimenters. Each aliquot was introduced into three commonly used drainage systems: UnoVac 600 mL (Unomedical, Birkerød, Denmark) (Fig. 1), RedoVac 600 mL (PFM Medical, Köln, Germany) (Fig. 2) and Jackson-Pratt 100 mL (Cardinal Health, Dublin, OH, USA) (Fig. 3), producing a total of 12 testing samples. These samples were randomly presented to consenting nursing (n = 36) and medical (n = 29) staff in the surgical ward, who then estimated the drain volumes by direct observation of the fluid levels’ proximity to the volume gradients of each drainage system. The results were recorded by an independent observer. ANZ J Surg 85 (2015) 327–329
328
Fig. 1. UnoVac drainage system containing black tea solution mimicking haemoserous fluid.
Yue et al.
Fig. 4. Modified bar and whisker graph demonstrating the absolute difference between measurements from hospital staff and actual volume at 10, 25, 40 and 90 mL. Whiskers represent 95% confidence interval.
of observer (nurses or doctors). The accuracy of the reading is expressed as the absolute difference between observed and actual volumes unless otherwise stated. The significance level for the study was set at 0.05, with Bonferroni (post hoc) correction applied to all significant pairwise comparisons.
Results Fig. 2. RedoVac drainage system containing black tea solution mimicking haemoserous fluid.
Comparison between drainage systems For moderate-to-high volumes (≥25 mL) the volume of fluid in the Jackson-Pratt system was generally more accurately estimated when compared with UnoVac and RedoVac. At low volumes (10 mL) there was no difference in the accuracy of volume reading between the drain systems (Fig. 4).
Comparison between drainage volumes Drainage systems were in general less accurate at high volumes (90 mL) than at low volumes (10 mL) (P < 0.0001).
Comparison between nursing staff and doctors No significant difference in accuracy was identified between nurses and doctors. Fig. 3. Jackson-Pratt drainage system containing black tea solution mimicking haemoserous fluid.
Statistical analysis In order to analyse and compare the accuracy of readings between different drainage systems, different drainage volumes and different hospital staff (nursing versus medical), a three-way analysis of variance with repeated measures was performed. The three independent variables were the type of drain system (UnoVac, RedoVac and Jackson-Pratt), the drain volume (10, 25, 40 and 90 mL) and the type
Discussion Appropriate use of wound drainage has been documented to decrease post-operative wound seroma and haematoma formation.1–3 For example, the use of suction drainage in breast surgery has been shown to decrease the incidence of seroma.2,9–12 In head and neck surgery, Perkins et al. found that use of surgical wound drains decreased the rate of seroma and haematoma formation in patients undergoing facelift surgery.13 Although there are benefits to surgical wound drainage, the risk of infection increases proportionately with the duration of drainage © 2014 Royal Australasian College of Surgeons
Accuracy of drainage systems
placement.5,14,15 To determine the optimal time to remove drain tubes, the measurement of wound drainage volume is used in many types of surgery.3,4,6–8 For example, post mastectomy management, most surgeons advocate removal of drains when the daily drainage falls below 30 mL regardless of the time elapsed post surgery.3,4,6–8 A higher incidence of seroma formation was observed post removal of drains when the 24-h drainage volume was >50 mL.6 It is therefore important for medical and nursing staff to estimate drainage system volumes accurately to ensure appropriate timing of drain tube removal. Measurements of volume amounts are generally performed by one of two methods: direct observation of the fluid in the drainage system or through emptying of the fluid into a measuring container. In clinical practice, it is often preferable to estimate the drainage volume via direct observation, as this reduces the likelihood that suction drainage systems will inadvertently be changed to an ‘off suction’ state and allows a fast measurement reading of volume in drain. UnoVac 600 mL (Fig. 1), RedoVac 600 mL (Fig. 2) and JacksonPratt 100 mL (Fig. 3) were selected for this study because they are the most commonly available drainage systems for surgical wounds in Australia. Among these systems, we recommend using the Jackson-Pratt drainage system as it was markedly more accurate than UnoVac and RedoVac for operations where drain tube volumes are the main determinant of drain tube removal, although the aberrant finding of increased accuracy of Jackson-Pratt drains may be attributed to its smaller size of 100 mL. To put this finding into clinical perspective, our study estimates that only 5% of nurses and 1% of doctors will report values more than 30 mL in Jackson-Pratt drainage systems filled with 25 mL of fluid; therefore, these drains are more likely to be removed at the appropriate time. On the other hand, 58% of nurses and 51% of doctors will report values more than 30 mL when the RedoVac drainage system is used. Consequently when a RedoVac drainage system is used, the drains are more likely to be kept in for longer than required. Furthermore, in a drainage system that is filled with 40 mL of fluid, 0% of doctors will report less than 30 mL using the JacksonPratt system; however, 9% of doctors will report less than 30 mL using the UnoVac system. This translates to premature removal of the UnoVac system drain tubes in approximately 10% of the cases if volume of less than 30 mL is used as a threshold for drain removal. This study found that doctors and nurses are equally proficient in estimating drain tubes. Some differences may be attributed to their familiarity with the type of drainage system being used. For example, nurses tend to be more accurate than doctors with the UnoVac system. Using the UnoVac drainage systems, doctors are more accurate than nurses for 10 mL of aliquots, but are less accurate for higher volumes. However, the reduced accuracy for 10-mL volumes in nurses using UnoVac compared with doctors may be explained by nurses tending to round down to 0 mL for low volumes in drains. This study demonstrated that the accuracy of volume measurement is diminished at the extremes of drain volumes. Accuracy is expected to be worse with greater drain volumes, given that the more volume there is, the greater the margin for error. The authors recommend emptying the drainage systems when volumes are esti© 2014 Royal Australasian College of Surgeons
329
mated to be greater than 90 mL to ensure continued accuracy of drain tube volume estimates. If emptying of drainage systems at high volumes is not possible, we recommend use of the Jackson-Pratt or UnoVac drainage systems as medical and nursing staff were more accurate with these drainage systems compared with the RedoVac system at volumes greater than 90 mL. The aberrant finding of reduced accuracy with 10-mL volumes may be explained by the fact that at very low volumes, accuracy may also be impeded by other factors, such as the tendency for observers to round down to zero, or the difficulty in visualizing the drain fluid when making an assessment.
Conclusion Doctors and nurses are equally proficient in estimating drain tubes. This study suggests that for moderate-to-high volumes (≥25 mL), Jackson-Pratt is the drainage system of choice. The accuracy of volume measurement is diminished at the extremes of drain volumes, emptying of drainage systems is recommended to avoid overfilling of drainage systems.
References 1. Liu CD, McFadden DW. Overnight closed suction drainage after axillary lymphadenectomy for breast cancer. Am. Surg. 1997; 63: 868–70. 2. Aitken DR, Hunsaker R, James AG. Prevention of seromas following mastectomy and axillary dissection. Surg. Gynecol. Obstet. 1984; 158: 327–30. 3. Scevola S, Youssef A, Kroll SS, Langstein H. Drains and seromas in TRAM flap breast reconstruction. Ann. Plast. Surg. 2002; 48: 511–4. 4. Williams J, Toews D, Prince M. Survey of the use of suction drains in head and neck surgery and analysis of their biomechanical properties. J. Otolaryngol. 2003; 32: 16–22. 5. Drinkwater CJ, Neil MJ. Optimal timing of wound drain removal following total joint arthroplasty. J. Arthroplasty 1995; 10: 185–9. 6. Yii M, Murphy C, Orr N. Early removal of drains and discharge of breast cancer surgery patients: a controlled prospective clinical trial. Ann. R. Coll. Surg. Engl. 1995; 77: 377–9. 7. Tarazi R, Esselstyn CB Jr, Kuivila T, Hardesty I. Early hospital discharge following mastectomy. Cleve. Clin. Q. 1984; 51: 579–84. 8. Cohen AM, Schaeffer N, Chen ZY, Wood WC. Early discharge after modified radical mastectomy. Am. J. Surg. 1986; 151: 465–6. 9. Morris AM. A controlled trial of closed wound suction. Br. J. Surg. 1973; 60: 357–9. 10. Cameron AE, Ebbs SR, Wylie F, Baum M. Suction drainage of the axilla: a prospective randomized trial. Br. J. Surg. 1988; 75: 1211. 11. Soon PS, Clark J, Magarey CJ. Seroma formation after axillary lymphadenectomy with and without the use of drains. Breast 2005; 14: 103–7. 12. Barton A, Blitz M, Callahan D, Yakimets W, Adams D, Dabbs K. Early removal of postmastectomy drains is not beneficial: results from a halted randomized controlled trial. Am. J. Surg. 2006; 191: 652–6. 13. Perkins SW, Williams JD, Macdonald K, Robinson EB. Prevention of seromas and hematomas after face-lift surgery with the use of postoperative vacuum drains. Arch. Otolaryngol. Head Neck. Surg. 1997; 123: 743–5. 14. Willett KM, Simmons CD, Bentley G. The effect of suction drains after total hip replacement. J. Bone Joint Surg. Br. 1988; 70: 607–10. 15. Simchen E, Rozin R, Wax Y. The Israeli Study of Surgical Infection of drains and the risk of wound infection in operations for hernia. Surg. Gynecol. Obstet. 1990; 170: 331–7.
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