|ORIGINAL RESEARCH REPORT
|Year : 2019 | Volume
| Issue : 2 | Page : 57-60
“Hidden fluid” in the critically ill patient: A wake-up call
Babatunde Babasola Osinaike1, Arinola A Sanusi1, Shete Kunle Phillips2
1 Department of Anaesthesia, College of Medicine, University of Ibadan; Department of Anaesthesia, University College Hospital, Ibadan, Oyo State, Nigeria
2 Department of Anaesthesia, University College Hospital, Ibadan, Oyo State, Nigeria
|Date of Web Publication||20-May-2019|
Dr. Shete Kunle Phillips
Department of Anaesthesia, University College Hospital, PMB 5116, Ibadan, Oyo State
Source of Support: None, Conflict of Interest: None
Background and Aim: Fluid overload and unfavorable outcomes in critically ill patients have been demonstrated in many clinical settings, such as acute lung injury/acute respiratory distress syndrome, septic patients, and those with acute kidney injury. Fluid overload has been reported in up to 70% of patients admitted to the intensive care unit (ICU). Fluid optimization strategies are often used to prevent fluid overload. Less obvious sources of fluid intake are often overlooked. The aim of this study was to determine the contribution of intravenous medications to daily fluid intake and balance in our ICU. Methodology: We conducted a retrospective study on adult patients admitted to the ICU of the University College Hospital, Ibadan, from January to December 2015. Daily ICU record charts were reviewed to determine the sources and volumes of various fluids for the study patients. Fluid other than intravenous fluid, enteral feeds, and blood/blood products were categorized as hidden fluid. These were mainly intravenous medications. Data were analyzed using the Statistical Package for the Scientific Solutions Version 20. Results: A total of 286 patients were admitted during the study year. There were 26 nonadults (≤16 years) excluded, and the records of 74 patients were not available. The mean daily volume of drug solutions (473.4 ml) was about 16% of the mean daily intake (2846.1 ml). The percentage of hidden fluid was highest in the neurology group (26.7%). No group had <10%. The use of vasopressor was significantly associated with higher volume of hidden fluid (P = 0.001). Hidden fluid constituted 13% of the total fluid administered during the study period. Conclusion: Intravenous drug solutions were important contributions to fluid intake and balance in our review. ICU clinician should always consider this when calculating daily fluid maintenance. Further study is needed to determine their contribution to the development of fluid overload and ICU mortality.
Keywords: Fluid balance, fluid overload, hidden fluid, intensive care unit, intravenous medication
|How to cite this article:|
Osinaike BB, Sanusi AA, Phillips SK. “Hidden fluid” in the critically ill patient: A wake-up call. J Clin Sci 2019;16:57-60
| Introduction|| |
Inadvertent fluid overload and unfavorable outcomes in critically ill patients have been demonstrated in many clinical settings such as acute lung injury (ALI) or acute respiratory distress syndrome (ARDS),, as well as in patients with sepsis  and those with acute kidney injury. Fluid optimization strategies are often used to prevent fluid overload. Less obvious sources of fluid intake are often overlooked; they include intravenous medication pushes, intravenous drugs, flushes to maintain catheter patency, and continuous infusions of vasoactive drugs and sedatives, especially when they are administered as large-volume infusions in the intensive care unit (ICU) with a paucity of infusion pumps. A study showed that they constituted important sources of fluid intake.
In a study by Basso et al., bioelectric impedance vector analysis was employed to assess hydration in 64 patients following ICU admission. They observed that overhydration was seen in 70% of the patients for most period of the ICU stay. Fluid management is a key feature in the hemodynamic resuscitation of critically ill patients, and its optimization is important for favorable patient outcome. Assessing fluid responsiveness and balance in the critically ill is important to avoid unnecessary and potentially deleterious fluid administration and overload.
Fluid overload is related to increased mortality and also results in several complications such as pulmonary edema, cardiac failure, delayed wound healing, tissue breakdown, and impaired bowel function; hence, management and optimization of fluid balance become a central component of the management of critically ill patients. Fluid overload has been shown to be associated with higher mortality, increased health-care resources, and increased cost of care in critically ill patients. This study aims to determine the contribution of intravenous medications to daily fluid intake and balance in our ICU.
| Methodology|| |
We conducted a retrospective study on adult patients admitted to the ICU of the University College Hospital (UCH), Ibadan, between January and December 2015. The ICU of the UCH Ibadan is a 12-bed general ICU that admits medical, surgical, and obstetric patients.
Daily ICU patient charts were reviewed to determine the sources and volumes of various fluids for the study patients. Fluid other than intravenous fluid, enteral feeds, and blood/blood products were categorized as "hidden fluid." The mean daily volume of fluid in the different patient categories following common ICU interventions were computed. Only patients who spent at least 24 h were recruited and no patient was recruited more than once.
Data were analyzed using the Statistical Package for the Scientific Solutions Version 20. Categorical data were expressed as frequencies and percentages and continuous variables were presented as means (standard deviation). Analysis of variance was used to compare the volume of hidden fluid in the different categories, and the significance level was set at P < 0.05.
| Results|| |
A total of 286 patients were admitted to the ICU during the study period. Twenty-six patients aged <16 years were excluded, and the records of 74 patients were not available for review. Thus, only records of 186 patients were included in the analysis. The baseline characteristics of the patients admitted during the study period are shown in [Table 1].
The mean daily volume for drug solutions was 473.4 ml, which was about 16% of the mean daily intake that was 2846.1 ml (including blood/blood products) [Table 2].
When the mean volume of hidden fluid was compared to the mean daily fluid intake, those in the neurology group had the highest percentage (26.7%), and no group had <10% [Figure 1]. The average volume of hidden fluid in the respiratory, neurology, sepsis, and obstetric related admissions was more than 50% of average daily balance [Figure 2].
|Figure 1: Mean volume of daily hidden fluid in the different patient groups|
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The use of vasopressor was significantly associated with higher volume of hidden fluid (P = 0.001) compared to mechanical ventilation and the use of diuretics [Figure 3].
|Figure 3: Volume of hidden fluid related to interventions in the intensive care unit|
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When the total volume of fluid employed over the study period was summed up (1,898,774 ml), hidden fluid constituted 13% of the fluid administered during the study period [Figure 4].
| Discussion|| |
This study found that about 10%–25% of daily fluid input was from intravenous medications, and this result is similar to 25.7% obtained by Bashir et al., when the mean volume of intravenous medications was compared to that of standard maintenance fluid. This finding may negatively influence the outcome in the critically ill patients, for example, increased length of hospital stay, cost, and increased mortality. Upadya et al. demonstrated that a negative fluid balance was independently associated with weaning success in mechanically ventilated patients. Furthermore, Sakr et al. demonstrated that mean fluid balance was an independent determinant of ICU outcome in patients with ALI and ARDS.
Child et al. demonstrated that the fluid overload cohort had a significantly higher inpatient mortality than the nonfluid overload cohort (20% vs. 16.8%, P < 0.001) and are more likely to use ventilator during their stay (47.7% vs. 28.3%, P < 0.001).
In patients with sepsis, the relationship between a positive fluid balance and a negative outcome has also been described. Alsous et al. demonstrated an increased mortality risk in patients failing to achieve a negative fluid balance within the first 3 days of treatment (relative risk 5.0, 95% confidence interval, 2.3–10.9).
As shown in [Figure 2], there is a higher volume of "hidden fluid" in relation to the daily fluid balance in the respiratory, neurologic, sepsis, and obstetric related groups. This finding could be because these groups of patients were likely to have presented with shock (hemorrhagic, septic, and neurogenic), with concomitant antibiotics usage and need for sedation and vasopressors, all contributing to higher fluid use.
Furthermore, the significantly higher volume of "hidden fluid" in those who had vasopressor therapy may not be unexpected; a similar result was obtained by Bashir et al. This underlines the importance of careful calculation of maintenance fluid and the use of more concentrated solutions of vasoactive drugs, and this should help to reduce the volume of diluent. Furthermore, intravenous medications for analgesia and sedation, fluid diluents for antibiotics, electrolytes replacements, and intravenous flushes were employed to keep lines open before and after medication infusion, and all contribute to the increasing "hidden fluid" volume in ICU patients.
Undue fluid overload and a positive fluid balance may follow unchecked volume of intravenous drug medications. This study showed a significant contribution of intravenous drug solutions to positive fluid balance in some patient groups.
Fluids should be considered as drugs, each having indications, contraindications, and potential side effects (e.g., hyperchloremic metabolic acidosis). The 4 Ds of antibiotics should be adhered to during intravenous fluid therapy, i.e., drug, dosing, duration, and de-escalation. The type of fluid should be considered. There may be a need to give colloids instead of crystalloids to curtail administering large intravenous fluid. Furthermore, when large intravenous drug solutions are envisaged, fluid input can be reduced by making enteral feed more dense and/or reducing intravenous fluid volume. The maintenance volume and duration should be reviewed from time to time to prevent unwarranted fluid loading.
| Conclusions|| |
Intravenous drug solutions were important contributors (10%–25%) to fluid intake and balance in our review. The ICU clinician should always consider this when calculating daily fluid maintenance. Further study is needed to determine the contribution of intravenous medications to the development of fluid overload and ICU mortality.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]