Protocol-driven vs. physician-driven electrolyte replacement in adult critically ill patients
Abstract and Figures
The intensive care unit is a dynamic environment, where high numbers of patients cared for by health care workers of different experiences and backgrounds might result in great variability in patient care. Protocol-driven interventions may facilitate timely and uniform care of common problems, like electrolyte disturbances. We prospectively compared protocol-driven (PRD) vs. physician-driven (PHD) electrolyte replacement in adult critically ill patients.
In the first month of the two-month study, potassium, magnesium, and phosphate levels were checked by a physician before ordering replacement (PHD replacement period). Over the second month, ICU nurses proceeded with replacement according to the protocol (PRD replacement period). We collected demographic data, admission diagnosis, number of potassium, magnesium, and phosphate levels done per day, number of low levels per day, number of replacements per day, time between availability of results to ordering replacement, time to starting replacement, post-replacement levels, serum creatinine, replacement dose, arrhythmias and replacement route.
During the PHD replacement period, 43 patients meeting the inclusion criteria were admitted to the ICU, while 44 were admitted during the PRD month. The mean time (minutes) from identifying results to replacement of potassium, phosphate and magnesium was significantly longer with PHD replacement compared with PRD replacement (161, 187, and 189 minutes vs. 19, 26, and 19 minutes) (P<0.0001). The number of replacements needed and not given was also significantly lower in the PRD replacement period compared with the PHD replacement period (2, 4, and 0 compared with 9, 6 and 0) (P<0.05). No patients had high post-replacement serum concentrations of potassium, phosphate or magnesium.
This study shows that a protocol-driven replacement strategy for potassium, magnesium and phosphate is more efficient and as safe as a physician-driven replacement strategy.
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... [2,[9][10][11] Unfortunately, there is great variability in the dosing, timing, and monitoring of electrolyte repletion by individual clinicians. [6,[12][13][14] By virtue of this, many institutions have implemented electrolytes replacement protocols. Numerous trials have documented the utility, safety, effectiveness and efficacy of protocol driven care among the CIPs. ...
... This tool was developed by the researcher after reviewing the relevant literature. [1,13,33,34] It was used to assess the effect of applying unit routine electrolytes replacement interventions and nurses driven electrolytes repletion protocol on electrolyte disturbances control. It consists of two parts: ...
... These findings comes in accordance with by Kanji and Jung (2009), [35] Todd et al. (2009), [36] and Hijazi and Al-Ansari (2005). [13] As regard the effectiveness of electrolytes protocol, first, the mean potassium level did not differ between the study and the control group in the first day without difference in the replacement doses, but there was a highly statistical differ-ence throughout the following sixth consecutive days and in the total mean of potassium level with significantly lower replacement doses in the study group. Moreover, patients in the study group have achieved the target potassium level (4-5) mEq/dl from the second day of the study in contrary with patients in the control group who have not achieved this target level throughout the seven consecutive days of the study. ...
Background and objective: Electrolyte disturbances remain a common lifesaving issue in the intensive care units. They are associated with increased morbidity and mortality. They are mostly resulted secondary to critical illness itself or associated treatment modalities. Therefore, electrolytes repletion should be done effectively and timely. This could be ensured using nurse driven protocols rather than traditional methods of repletion. These protocols are nurse initiated and collaboratively developed. They have been shown to improve patient care outcomes through the provision of high quality care. They are increasingly being used in the critical care setting. Objective: Determine the effect of applying nurses driven electrolytes repletion protocol on electrolytes disturbance control among critically ill patients.Methods: Quasi experimental research design was used. Sixty two critically ill patients with electrolytes loss were enrolled in the study at Alexandria Main University Hospital intensive care units, Egypt. All episodes of electrolyte loss were evaluated. Repletion of electrolyte loss was done according to unit routine for the control group and nurses driven electrolytes repletion protocol for the study group. Episodes of electrolyte disturbances, adverse events and timing of repletion were evaluated.Results: Neurological disorders represent the most encountered diagnosis. The most common cause of electrolyte loss in was the use of diuretics. Furthermore, there was a highly statistical difference between the two groups as regard electrolytes levels, effectiveness and timing of replacement.Conclusions: Application of nurses driven electrolyte repletion protocol resulted in improvements in the effectiveness and timeliness of electrolyte replacement.
... Potassium replacement protocols are increasingly being used throughout adult critical care settings (Zielenski et al., 2017) to standardise practice, ensure uniform, effective, and timely therapy (Hijazi & Al-Ansari, 2005) and reduce actual or potential harm to patients (Webster et al., 2015;Zielenski et al., 2017). A retrospective observational study conducted in the USA with N = 300 medical patients treated using a potassium replacement protocol demonstrated a significant improvement in the time from blood collection to potassium replacement (p < 0.0001) and time to achieve target potassium level (p <.05) (Zielenski et al., 2017). ...
... When the design and development process is multidisciplinary and collaborative, protocols improve patient outcomes (Wall et al., 2001), increase patient safety (Kahol et al., 2011), reduce medical errors (Chang et al., 2012), and enhance routine clinical care (Holcomb et al., 2001;Meade & Ely, 2002). Protocol directed interventions contribute to highly efficient care and productive use of resources (Hijazi & Al-Ansari, 2005;Zimmerman et al., 2003). Importantly however, protocol driven care must also be underpinned by sound clinical judgement and expert decision making (Chang et al., 2012;Wall et al., 2001), with ICU nurses needing to possess a thorough knowledge of electrolyte homeostasis, the patient's clinical condition and responses to treatment and management (Kraft et al., 2005). ...
Background:
Potassium replacement protocols are used to standardise practice, reduce risk, and ensure timely potassium replacement, but there is considerable variability in their development and use, particularly as part of critical care nursing practice.
Aim:
To synthesise the research evidence on how potassium replacement protocols are used in adult critical care; and how critical care nurses' role and practice is influenced by a potassium replacement protocol. The research question was 'How are protocols used by intensive care clinicians to guide potassium replacement in adult critical care?'
Design:
A structured integrative review was undertaken. A combination of keywords, synonyms, and Medical Subject Headings were used across the Ovid Medline and Embase databases. Records were independently assessed against inclusion and exclusion criteria. All papers were assessed for quality. A narrative synthesis was used to analyse and present the findings.
Results:
Ten studies were included in this review from 4076 records identified. Narrative synthesis revealed five categories: (i) protocol design demonstrating variation in protocol mechanisms, (ii) protocol rationale eliciting reasonings for protocol implementation, (iii) protocol use describing how protocols were nurse-driven enabling nursing autonomy (iv) protocol adherence highlighting variability in protocol compliance and (v) critical care nurse acceptability and feasibility coupling greater shared responsibility for patient care and improved clinician satisfaction.
Conclusion:
Safe, high-quality care, supported by evidence continues to be a priority. Protocolised potassium replacement can improve patient outcomes and promote nurses' autonomy, efficiency, and job satisfaction.
Implications for clinical practice:
Recognising and promoting critical care nurses' expert assessment skills and clinical decision-making is essential for optimising efficient, safe, and high-quality patient care. Although protocol deviations are accommodated in protocol development, comprehensive documentation to justify protocol deviations is key to justifying practice. Understanding protocol deviations are crucial to inform future protocol development, improvements, and evaluation to further enhance critical care nursing practice.
... 15,16 Electrolyte repletion in the ICU is a common daily practice to normalize derangements. [17][18][19][20] These electrolytes are frequently administered intravenously and diluted in the form of a crystalloid or other solution. However, the impact of this practice on the daily FB has not been adequately quantified. ...
... 17 Furthermore, active repletion of all electrolytes, except phosphate, resulted in minimal effect on serum levels. Protocolbased electrolyte repletion orders might have resulted in improved provider satisfaction, although not necessarily a decrease in adverse events, [18][19][20][21][22] and their impact on the patients' FB remains unclear. Although there is no protocolized electrolyte repletion in our surgical ICU, the culture of repletion is perpetuated. ...
Avoiding excess fluid administration is necessary when managing critically ill surgical patients. The aim of this study was to delineate the current practices of IV electrolyte (IVE) replacement in a surgical ICU and quantify their contribution to the fluid balance (FB) status. Patients admitted to the surgical ICU over a six-month period were reviewed. Patients undergoing dialysis and those with ICU stay <72 hours were excluded. A total of 248 patients were included. The median age was 60 years, and 57 per cent were male. Overall, 1131 patient ICU days were analyzed. The median daily FB was 672 mL. IVEs were administered in 62 per cent of ICU days. In days that IVEs were used, negative FB was significantly less likely to be achieved (62% vs 69%, P = 0.02). The most commonly administered IVE was calcium (32% of ICU days); however, the largest volume of IVE was administered in the form of phosphorus (median 225 mL). Diuretics were administered in 17 per cent of ICU days. Patients who received diuretics were significantly more likely to receive IVE (70% vs 61%, P = 0.02). Administration of IVE may contribute to the daily positive FB of surgical ICU patients. Implementation of practices that can ameliorate this effect is encouraged.
... Baseline demographics and clinical characteristics were described by using descriptive statistics. We determined that a sample size of 272 days of replacement would have 90% power to detect a 15.5% absolute difference (actual 28% vs expected 12.5%) in the percentage of hypokalemic events with adequate replacement at a = .05. [3][4][5][6][7] ...
... overall and 35% when rule-of-thumb estimation was provided) of potassium replacements in our study that resulted in attainment of the target serum concentration is within the range reported for other cohorts of critically ill patients in whom replacement was determined by using or not using a replacement protocol. [4][5][6][7][8][9] Before beginning use of a nurseinitiated, evidence-based order form in an MICU, Owen et al 5 observed achievement of the target serum potassium concentration in 18% of cases. After implementation, the percentage of target attainment increased to 72%. ...
Background:
Rules of thumb for potassium replacement are used in intensive care units despite minimal empirical validation.
Objective:
To evaluate the effectiveness and safety of rule-of-thumb potassium replacement in critically ill patients with mild and moderate hypokalemia.
Methods:
A retrospective, observational study was done of patients with mild (potassium, 3-3.9 mEq/L) and moderate (potassium, 2-2.9 mEq/L) hypokalemia admitted to a medical intensive care unit who received potassium replacement. Expected and actual frequencies of replacement that achieved target potassium concentrations (≥ 4 mEq/L) were compared by using a χ2 test. Logistic regression analysis was used to assess whether rule-of-thumb administration affected the probability of target attainment within 24 hours of replacement.
Results:
Serum potassium concentrations were checked within 24 hours after potassium replacement on 354 of 577 days (61.4%) when replacement was provided. Concentrations were within target range in 82 instances (23.2%). Of 62 episodes of replacement expected to achieve the target according to the rule-of-thumb estimation, 22 did (35%). Rule-of-thumb administration was associated with greater likelihood of target attainment (odds ratio, 2.12; 95% CI, 1.18-3.85; P = .01). This difference in likelihood remained significant after adjustment for covariates (odds ratio, 2.18; 95% CI, 1.04-4.56; P = .04).
Conclusion:
In critically ill patients given potassium replacement without regard to a formal protocol, the target serum potassium concentration was achieved more often than expected according to the rule-of-thumb estimation but less than one-third of the time.
... Protocols for phosphorus replacement have been used since the 1970s [88]. Protocols standardize replacement and significantly increase the number of patients who are treated, reduce time to replacement, and result in more optimal dosing [80,89]. Protocols can help decrease infusion times safely through standardization. ...
Introduction
The majority of patients in the intensive care unit (ICU) are at risk for at least one electrolyte abnormality and critically ill patients are the most vulnerable population to the effects of suboptimal electrolyte levels. These patients have unique characteristics impacting implications of the electrolyte disturbances and management.
Areas Covered
In the ICU, magnesium, potassium, calcium, phosphorous, and sodium are the most commonly encountered electrolytes that can be abnormal in the critically ill. Critical illness both is affected by and affects disturbances of these electrolytes which can result in more severe illness, longer duration of mechanical ventilation, increased dialysis support, longer length of stay, and increased mortality. Often, patients have multiple imbalances that require correction. Removal or mitigation of the cause should be undertaken whenever possible and should be concurrent with any therapeutic management used to correct the electrolyte imbalance. Selection of medication to correct electrolyte imbalances should be undertaken according to available evidence and drug-specific characteristics that impact medication delivery in the critically ill.
Electrolyte disturbances, measurements, and corrections are ubiquitous in the ICU. Published literature on the management of electrolytes in the critically ill is limited. Management should consider factors unique to the critically ill when selecting optimal treatment approach and it is essential to individualize treatment to a patient’s unique needs and adapt management to the patient’s chancing clinical situation.
... Recommendations are presented in an interpretable and hierarchical way in which the system first suggests whether or not a repletion is needed, along with the best route for repletion, and followed by the most appropriate dosage in the event that the clinician chooses to administer a repletion. This is a more controlled system of prescribing electrolyte repletion, reflecting a quantitative data-driven decision-making pathway that caregivers often fail to follow if the decision-making process is provider-or protocol-driven [13]. The RL system provides flexibility in deciding what the clinical priorities should be, adapting them according to the electrolyte considered and to challenging clinical situations, such as chronic renal failure, liver failure, or severe morbidity, or to the workflows of the specific healthcare center [31]. ...
Both provider- and protocol-driven electrolyte replacement have been linked to the over-prescription of ubiquitous electrolytes. Here, we describe the development and retrospective validation of a data-driven clinical decision support tool that uses reinforcement learning (RL) algorithms to recommend patient-tailored electrolyte replacement policies for ICU patients. We used electronic health records (EHR) data that originated from two institutions (UPHS; MIMIC-IV). The tool uses a set of patient characteristics, such as their physiological and pharmacological state, a pre-defined set of possible repletion actions, and a set of clinical goals to present clinicians with a recommendation for the route and dose of an electrolyte. RL-driven electrolyte repletion substantially reduces the frequency of magnesium and potassium replacements (up to 60%), adjusts the timing of interventions in all three electrolytes considered (potassium, magnesium, and phosphate), and shifts them towards orally administered repletion over intravenous replacement. This shift in recommended treatment limits risk of the potentially harmful effects of over-repletion and implies monetary savings. Overall, the RL-driven electrolyte repletion recommendations reduce excess electrolyte replacements and improve the safety, precision, efficacy, and cost of each electrolyte repletion event, while showing robust performance across patient cohorts and hospital systems.
Rationale:
Potassium repletion is common in critically ill patients. However, practice patterns and outcomes related to different intensive care unit (ICU) potassium repletion strategies are unclear.
Objectives:
(1) Describe potassium repletion practices in critically ill adults, (2) compare the effectiveness of potassium repletion strategies, and (3) compare effectiveness and safety of specific potassium repletion thresholds on patient outcomes Methods: Retrospective analysis of the PINC AI Healthcare Database (2016-2022), including all critically ill adults admitted to an ICU on hospital day 1 and with a serum potassium level measured on hospital day 2. We determined the frequency of potassium repletion (any formulation) at each measured serum potassium level in each ICU, then classified ICUs as having threshold-based (a large increase in potassium repletion rates at a specific serum potassium level) or probabilistic (linear relationship between serum level and the repletion probability) patterns of repletion. Between patients in threshold-based and probabilistic repletion ICUs, we compared outcomes (primary outcome: potassium repletion frequency).. We reported unadjusted percentages per exposure group and the adjusted odds ratios (from hierarchical regression models) for each outcome. Among patients in threshold-based ICUs with the most common repletion thresholds (3.5 mEq/L and 4.0 mEq/L), we conducted regression discontinuity analyses to examine the effectiveness of potassium repletion at each potassium threshold.
Results:
We included 190,490 patients in 88 ICUs; 35.0% received at least one dose of potassium on the same calendar day. Rates of potassium repletion were similar between 22 threshold-based strategy ICUs (33.5%) and 22 probabilistic strategy ICUs (36.4%). There was no difference in the adjusted risk of potassium repletion between patients admitted threshold-based strategy ICUs versus probabilistic strategy ICUs (adjusted odds ratio 1.09, 95% confidence interval 0.76-1.57). In regression discontinuity analysis, crossing the 3.5 mEq/L threshold from high to low potassium levels resulted in a 39.1% (95% confidence interval 23.7-42.4) absolute increase in potassium repletion but no change in other outcomes. Similarly, crossing the 4.0 mEq/L threshold resulted in a 36.4% (95% confidence interval 22.4-42.2) absolute increase in potassium repletion but no change in other outcomes.
Conclusions:
Potassium repletion is common in critically ill patients and occurs over a narrow range of 'normal' potassium levels (3.5-4.0 mEq/L); use of a threshold-based repletion strategy to guide potassium repletion in ICU patients is not associated with clinically meaningful differences in outcomes.
Electrolyte repletion in the ICU is one of the most ubiquitous tasks in critical care, involving significant resources while having an unclear risk/benefit ratio. Prior data indicate most replacements are administered while electrolytes are within or above reference ranges with little effect on serum post-replacement levels and potential harm. ICU electrolyte replacement patterns were analyzed using the MIMIC-III database to determine the threshold governing replacement decisions and their efficiency. The data of serum values for potassium, magnesium, and phosphate before and after repletion events were evaluated. Thresholds for when repletion was administered and temporal patterns in the repletion behaviors of ICU healthcare providers were identified. Most electrolyte replacements happened when levels were below or within reference ranges. Of the lab orders placed, a minuscule number of them were followed by repletion. Electrolyte repletion resulted in negligible (phosphate), small (potassium), and modest (magnesium) post-replacement changes in electrolyte serum levels. The repletion pattern followed hospital routine work and was anchored around shift changes. A subset of providers conducting over-repletion in the absence of clinical indication was also identified. This pattern of behavior found in this study supports previous studies and may allude to a universal pattern of over-repletion in the ICU setting.
Background:
Torsade de pointes is a form of polymorphic ventricular tachycardia associated with heart rate-corrected QT (QTc ) interval prolongation. With approximately 24-61% of critically ill patients experiencing QTc interval prolongation, a predictive tool to identify high-risk patients could assist in monitoring and management in the intensive care unit (ICU). The Tisdale et al. Risk Score (TRS) is a predictive tool that was developed and validated in a Cardiac Critical Care Unit.
Objectives:
The objective of this study was to evaluate the predictive validity (sensitivity and specificity) and likelihood ratios of the TRS in a medical ICU.
Methods:
This was a longitudinal, retrospective, cohort study of consecutive patients who met the inclusion criteria from October 2017 to June 2018 with a sample size of 264 patients. The sample size was derived based on the number of TRS covariates and an exploratory variable. Baseline characteristics and risk factors were documented from electronic health records. The first occurrence of QTc interval prolongation, defined as a QTc interval >500ms or an increase ≥60ms above baseline, was the primary endpoint. Main Results The sensitivity and specificity of the TRS for low-risk patients against the moderate-risk and high-risk patients were 97% (95% CI 91-99%) and 16% (95% CI 11-23%), respectively. These results corresponded to a positive likelihood ratio of 1.15 (95% CI 1.07-1.24) and a negative likelihood ratio of 0.20 (95% CI 0.06-0.65).
Conclusions:
In this study, the TRS showed high sensitivity, making it useful in identifying patients at low risk of QTc interval prolongation. However, the low specificity of the TRS suggests that it should not be used to identify patients at moderate or high risk of QTc interval prolongation. Future studies should explore a tool with improved specificity in critically ill patients to identify and manage those at risk of QTc interval prolongation.
Objective:
Hypokalemia in children following cardiac surgery occurs frequently, placing them at risk of life-threatening arrhythmias. However, renal insufficiency after cardiopulmonary bypass warrants careful administration of potassium (K+). Two different nurse-driven protocols (high dose and tiered dosing) were implemented to identify an optimal K+ replacement regimen, compared to an historical low-dose protocol. Our objective was to evaluate the safety, efficacy, and timeliness of these protocols.
Design:
A retrospective cohort review of pediatric patients placed on intravenous K+ replacement protocols over 1 year was used to determine efficacy and safety of the protocols. A prospective single-blinded review of K+ repletion was used to determine timeliness.
Patients:
Pediatric patients with congenital or acquired cardiac disease.
Setting:
Twenty-four-bed cardiothoracic intensive care unit in a tertiary children's hospital.
Interventions:
Efficacy was defined as fewer supplemental potassium chloride (KCl) doses, as well as a higher protocol to total doses ratio per patient. Safety was defined as a lower percentage of serum K+ levels ≥4.8 mEq/L after a dose of KCl. Between-group differences were assessed by nonparametric univariate analysis.
Results:
There were 138 patients with a median age of 3.0 (interquartile range: 0.23-10.0) months. The incidence of K+ levels ≥4.8 mEq/L after a protocol dose was higher in the high-dose protocol versus the tiered-dosing protocol but not different between the low-dose and tiered-dosing protocols (high dose = 2.2% vs tiered dosing = 0.5%, P = .05). The ratio of protocol doses to total doses per patient was lower in the low-dose protocol compared to the tiered-dosing protocol ( P < .05). Protocol doses were administered 45 minutes faster ( P < .001).
Conclusion:
The tiered-dosed, nurse-driven K+ replacement protocol was associated with decreased supplemental K+ doses without increased risk of hyperkalemia, administering doses faster than individually ordered doses; the protocol was effective, safe, and timely in the treatment of hypokalemia in pediatric patients after cardiac surgery.
Context Delirium is a common problem in the intensive care unit (ICU). Accurate
diagnosis is limited by the difficulty of communicating with mechanically
ventilated patients and by lack of a validated delirium instrument for use
in the ICU.Objectives To validate a delirium assessment instrument that uses standardized
nonverbal assessments for mechanically ventilated patients and to determine
the occurrence rate of delirium in such patients.Design and Setting Prospective cohort study testing the Confusion Assessment Method for
ICU Patients (CAM-ICU) in the adult medical and coronary ICUs of a US university-based
medical center.Participants A total of 111 consecutive patients who were mechanically ventilated
were enrolled from February 1, 2000, to July 15, 2000, of whom 96 (86.5%)
were evaluable for the development of delirium and 15 (13.5%) were excluded
because they remained comatose throughout the investigation.Main Outcome Measures Occurrence rate of delirium and sensitivity, specificity, and interrater
reliability of delirium assessments using the CAM-ICU, made daily by 2 critical
care study nurses, compared with assessments by delirium experts using Diagnostic and Statistical Manual of Mental Disorders, Fourth
Edition, criteria.Results A total of 471 daily paired evaluations were completed. Compared with
the reference standard for diagnosing delirium, 2 study nurses using the CAM-ICU
had sensitivities of 100% and 93%, specificities of 98% and 100%, and high
interrater reliability (κ = 0.96; 95% confidence interval, 0.92-0.99).
Interrater reliability measures across subgroup comparisons showed κ
values of 0.92 for those aged 65 years or older, 0.99 for those with suspected
dementia, or 0.94 for those with Acute Physiology and Chronic Health Evaluation
II scores at or above the median value of 23 (all P<.001).
Comparing sensitivity and specificity between patient subgroups according
to age, suspected dementia, or severity of illness showed no significant differences.
The mean (SD) CAM-ICU administration time was 2 (1) minutes. Reference standard
diagnoses of delirium, stupor, and coma occurred in 25.2%, 21.3%, and 28.5%
of all observations, respectively. Delirium occurred in 80 (83.3%) patients
during their ICU stay for a mean (SD) of 2.4 (1.6) days. Delirium was even
present in 39.5% of alert or easily aroused patient observations by the reference
standard and persisted in 10.4% of patients at hospital discharge.Conclusions Delirium, a complication not currently monitored in the ICU setting,
is extremely common in mechanically ventilated patients. The CAM-ICU appears
to be rapid, valid, and reliable for diagnosing delirium in the ICU setting
and may be a useful instrument for both clinical and research purposes.
Background
Therapist-implemented protocols have beenused to extubate or wean patients in the ICU setting. Barlow Respiratory Hospital (BRH) functions as a center for weaning patientsfrom prolonged mechanical ventilation (PMV) in the post-ICU setting ofa long-term acute-care (LTAC) facility. A therapist-implementedpatient-specific (TIPS) weaning protocol was developed at BRH tostandardize weaning from PMV.
Study design
Prospective cohort study with historical control.
Methods
A weaning protocol incorporating the proceduresand pace of LTAC weaning was developed using available scientificevidence and expert consensus. After training of staff, collection andanalysis of pilot data, and revisions and refinement of the protocol, the TIPS protocol was implemented hospital-wide. It was monitored foroutcome, variance, and respiratory care practitioner (RCP) andphysician compliance.
Results
Forty-six RCPs workedwith eight pulmonologists treating 271 consecutive patients admittedfor weaning from PMV during an 18-month period. Nineteen patients wereexcluded from weaning attempts by any method after initial physicianevaluation. The remaining 252 patients (9,135 total ventilator days)were compared with a group of 238 patients treated by the samephysicians in the 2 years before instituting protocol weaning. Mediantime to wean declined significantly from 29 days in historical controlsubjects to 17 days for TIPS protocol patients (p < 0.001). Outcomes(scored at discharge) were comparable for the two groups (TIPS group vscontrol group): weaned, 54.7% vs 58.4%; ventilator-dependent, 17.9% vs 10.9%; died, 27.4% vs 30.7% (p = 0.10). Variances incurred byphysicians and RCPs were 324 and 136, respectively, for the 9,135ventilator days.
Conclusions
Patients weaned from PMVusing a new therapist-implemented protocol at BRH, an LTAC facilityspecializing in weaning, had significantly shorter time to weaning thanhistorical control subjects, with comparable outcomes. The weaningoutcome data collected after the implementation of the TIPS protocolare in fact attributable to its use, as we found a high degree ofcompliance with the protocol.
We retrospectively reviewed the charts of 308 admissions to a pulmonary disease ward and 100 admissions to the general medical service over one year to find the prevalence, sequelae, and etiology of hypophosphatemia. The overall prevalence of low serum phosphate levels (less than 2.4 mg/dl) occurring at least once during hospitalization in chest patients was 17 percent, but was higher in patients with respiratory infections (28 percent). Moreover, the prevalence of hypophosphatemia on admission (before institution of intravenous fluid or drug therapy) was ten times higher in patients with respiratory infections than in patients with noninfectious respiratory illness or general medical patients (21 vs 2 percent, p less than 0.001). Serum phosphate less than 2.0 mg/dl occurred in 4 percent of patients. Twenty-seven percent of the patients (including two with ventilatory failure) with abnormally low serum phosphate levels had symptoms or signs of uncertain etiology later explicable by the presence of hypophosphatemia. The most common additional laboratory finding associated with hypophosphatemia was elevation of muscle enzymes. Although mortality was no higher in hypophosphatemic patients, hospital stay was twice as long as that of patients with normal levels of serum phosphate. No correlation was found between simultaneous arterial blood gases and serum phosphate levels. Two patients given antacids had severe hypophosphatemia and worsened ventilatory function; phosphate-binding antacids should be used judiciously in patients with severe respiratory disease, since they may lead to the development or worsening of hypophosphatemia and diminished ventilatory function.
Development of clinically effective protocols for use in managing mechanical ventilation is a time-consuming process that requires allocation of substantial resources. Clear development of protocol goals, incorporation of the best available evidence, coordination of a multidisciplinary protocol development team, and extensive bedside testing and protocol refinement are essential steps in protocol development. Safe implementation of the protocol requires an effective, ongoing training program. Protocols that direct clinical care require careful monitoring to ensure compliance and to identify adverse events. Finally, protocols must be followed and updated when new evidence becomes available.
Magnesium is clearly an important mineral in normal bodily function. This article details a number of abnormalities in physiologic function in the setting of hypomagnesemia and provides a strategy for Mg repletion.
To evaluate the efficacy and safety of potassium replacement infusions in critically ill patients.
Prospective cohort study.
Multidisciplinary critical care unit.
Forty-eight critically ill adult patients, age 25 to 86 yrs. Patients entered the study when hypokalemia (potassium less than 3.5 mmol/L) was noted on routine laboratory blood analysis. Most common primary diagnoses on ICU admission included postoperative cardiac surgery (n = 9), sepsis and multiple organ system failure (n = 9), complicated myocardial infarction (n = 7), and respiratory failure (n = 5).
Potassium chloride infusions (20, 30, or 40 mmol in 100 mL normal saline over 1 hr) were administered to patients for serum potassium levels of less than 3.5 but greater than 3.2 mmol/L (n = 26), 3.0 to 3.2 mmol/L (n = 11), and less than 3.0 mmol/L (n = 11), respectively. Serum and urine potassium levels were monitored during and for 1 hr after the infusion.
All patients tolerated the infusions without evidence of hemodynamic compromise, ECG change, or new dysrhythmia requiring treatment. The mean maximum potassium increase was 0.5 +/- 0.3 mmol/L, 0.9 +/- 0.4 mmol/L, and 1.1 +/- 0.4 mmol/L in the 20-, 30-, and 40-mmol groups, respectively. The increase in serum potassium was maximal at the completion of the infusion and was significant (p less than .05) compared with baseline in all groups. Peak potassium levels were the same in patients with normal renal function (n = 33) compared with those with renal insufficiency (n = 15). Urinary excretion of potassium increased in all groups during the infusion and was significant (p less than .05) in the 30- and 40-mmol groups, but was no greater in those patients who had received diuretics (n = 8) compared with those patients who had not (n = 40).
In the select group of hypokalemic patients studied, potassium infusions of 20 to 40 mmol delivered over 1 hr were safe to administer and effectively increased serum potassium levels in a dose-dependent and predictable fashion. Furthermore, these results were independent of the patient's underlying renal function or associated diuretic administration.
We studied the effects of hypophosphatemia on diaphragmatic function in eight patients with acute respiratory failure who were artificially ventilated. Their mean serum phosphorus level was 0.55 +/- 0.18 mmol per liter (normal value, 1.20 +/- 0.10). The contractile properties of the diaphragm were assessed by measuring the transdiaphragmatic pressure generated at functional residual capacity during bilateral supramaximal electrical stimulation of the phrenic nerves. Diaphragmatic function was evaluated in each patient before and after correction of hypophosphatemia, which was achieved by administration of 10 mmol of phosphorus (as KH2PO4) as a continuous infusion for four hours. After phosphate infusion, the mean serum phosphorus level increased significantly (1.33 +/- 0.21 mmol per liter, P less than 0.0001). The increase in serum phosphorus was accompanied by a marked increase in the transdiaphragmatic pressure after phrenic stimulation (17.25 +/- 6.5 cm H2O as compared with 9.75 +/- 3.8 before phosphate infusion, P less than 0.001). Changes in the serum phosphorus level and transdiaphragmatic pressure were well correlated (r = 0.73). These results strongly suggest that hypophosphatemia impairs the contractile properties of the diaphragm during acute respiratory failure, and they emphasize the importance of maintaining normal serum inorganic phosphate levels in such patients.
We retrospectively reviewed the charts of 308 admissions to a pulmonary disease ward and 100 admissions to the general medical service over one year to find the prevalence, sequelae, and etiology of hypophosphatemia. The overall prevalence of low serum phosphate levels (less than 2.4 mg/dl) occurring at least once during hospitalization in chest patients was 17 percent, but was higher in patients with respiratory infections (28 percent). Moreover, the prevalence of hypophosphatemia on admission (before institution of intravenous fluid or drug therapy) was ten times higher in patients with respiratory infections than in patients with noninfectious respiratory illness or general medical patients (21 vs 2 percent, p less than 0.001). Serum phosphate less than 2.0 mg/dl occurred in 4 percent of patients. Twenty-seven percent of the patients (including two with ventilatory failure) with abnormally low serum phosphate levels had symptoms or signs of uncertain etiology later explicable by the presence of hypophosphatemia. The most common additional laboratory finding associated with hypophosphatemia was elevation of muscle enzymes. Although mortality was no higher in hypophosphatemic patients, hospital stay was twice as long as that of patients with normal levels of serum phosphate. No correlation was found between simultaneous arterial blood gases and serum phosphate levels. Two patients given antacids had severe hypophosphatemia and worsened ventilatory function; phosphate-binding antacids should be used judiciously in patients with severe respiratory disease, since they may lead to the development or worsening of hypophosphatemia and diminished ventilatory function.
The relationship between serum concentration of certain electrolytes and the pathogenesis of ventricular arrhythmia in myocardial infarction has been the subject of frequent review. The role of hypophosphatemia in the pathogenesis of arrhythmia in patients with acute myocardial infarction has not been as well studied. In our study group of 325 consecutive patients admitted to the coronary care unit of a community hospital, 111 were confirmed to have had a myocardial infarction. Patients were continuously monitored for ventricular arrhythmia during the first 24 hours, and the electrocardiographic records were reviewed for documentation of arrhythmia. From an admission blood sample, measurement of electrolytes included serum phosphate, calcium, bicarbonate, potassium, and magnesium. Associations between ventricular tachycardia and serum electrolyte abnormalities including magnesium, potassium, phosphate, calcium, and bicarbonate were studied. Low phosphate (less than 2.6 mg/dL) was a significant predictor of ventricular tachycardia in the myocardial infarction group. In the entire group of 325 patients prior to the confirmation of myocardial infarction, both low bicarbonate and low phosphate were significant predictors of ventricular tachycardia during the first 24 hours of hospitalization. Although management of acidosis is considered early in the hospital course, phosphate replacement therapy is usually not as often considered. We recommend further study on the effectiveness of replacement therapy in hypophosphatemic patients with chest pain to reduce the risk of ventricular tachycardia.