INTRODUCTION — Intravenous (IV) infusion pumps are used to administer medications and fluids to all patients in perioperative and critical care settings. This topic will review the technology and use of IV infusion pumps, including simple manual flow regulators that use gravity and a roller clamp, syringe pumps, elastomeric pumps, more complex "smart" pumps that require operator programming, and closed-loop target-controlled infusion (TCI) systems. Since all IV infusion systems have potential to cause harm, the topic emphasis is on patient safety during use of these devices.

Additional aspects regarding prevention of medication errors and adverse drug events in the perioperative and other in-hospital settings are addressed in separate topics:

●(See "Prevention of perioperative medication errors".)

●(See "Prevention of adverse drug events in hospitals".)

OVERVIEW OF INFUSION DEVICES

●Types of infusion devices – The earliest (and still common) method for regulation of an intravenous (IV) infusion is a roller clamp on the IV tubing (see 'Manual flow regulators' below). This was followed by development of syringe and elastomeric pumps (see 'Syringe pumps' below and 'Elastomeric pumps' below). Early, simple pumps were set to deliver fluids at a given rate per hour and required the user to manually calculate and enter an infusion for each medication. More complex devices called "smart pumps" have been developed to improve medication safety and include a library with high-alert medications such as vasoactive agents (see 'Smart pumps' below) [1,2]. These pumps require programming, have high and low flow rate alarms with a dosing error reduction system (DERS), and are able to log alerts to improve clinical ability to detect and prevent serious medication errors. However, the benefits of smart pumps depend on the operator's compliance with the drug library incorporated within the pump [3,4]. Different areas of the hospital may have different drug libraries (eg, the operating rooms, cardiothoracic intensive care unit [ICU], medical ICU) may have a different library than the cardiothoracic ICU or the operating rooms. Target-controlled infusion (TCI) systems are computer-assisted IV infusion pumps that use pharmacokinetic and pharmacodynamic mathematical modeling to maintain a target plasma concentration of a medication. (See 'Target-controlled infusion systems' below.)

●Selection of infusion devices – General considerations for selection of an appropriate infusion device include:

•For high-alert IV medications such as vasoactive agents (eg, vasopressors, inotropes, vasodilators) or insulin, we prefer smart pumps containing a standardized medication library [1].

•For delivery of small quantities of IV fluids or medications such as sedatives, opioids, or vasoactive agents at a precise rate, syringe pumps are an appropriate choice and are widely available for use in the perioperative setting.

•For ambulatory infusion therapies (eg, continuous peripheral nerve blockade or IV analgesic agents for postoperative analgesia), elastomeric pumps are an appropriate choice.  

•For approximate control of IV fluid infusion rates in intraoperative settings where continuous observation is possible, the simplicity of assembly and use, ready availability, and low cost of manual flow regulators make them a good choice.

RISK MITIGATION — In the intraoperative setting, the continuous presence of an anesthesia provider means that IV infusions are monitored closely. Conversely, operator supervision of IV infusion pumps is more variable in most other inpatient areas of a hospital. (See "Prevention of adverse drug events in hospitals", section on 'Smart pumps' and "Prevention of perioperative medication errors", section on 'Medication infusion 'smart' pumps'.)

Risks for medication errors — A US Food and Drug Administration review noted that dosing errors accounted for 17 percent of in-hospital medication errors [2], and the primary cause is misprogramming of IV infusion pumps [5]. In the perioperative setting, errors during infusion of IV anesthetic agents include failure to deliver the intended agent, underdosing with possible awareness, and overdosing [6]. Although smart infusion pumps can theoretically prevent pump programming errors, they cannot prevent all error types [7]. It is still possible for a clinician to administer the wrong medication or wrong concentration, or to administer a medication to the wrong patient [8] (see "Prevention of perioperative medication errors", section on 'Types and incidence of errors'). Also, bypassing the preprogrammed dose limits in the smart pump medication library that is site-specific may result in inappropriate drug delivery [9], although this is sometimes necessary in the perioperative setting, particularly in emergency situations. Furthermore, violation of hospital policies such as using nonstandardized medication concentrations or covering labels on IV bags or tubing may contribute to drug dosing errors despite use of a smart pump. (See "Prevention of perioperative medication errors", section on 'Standardized concentrations of high-alert medications' and "Prevention of perioperative medication errors", section on 'Standardized labels'.)

Fortunately, not all medication errors result in an adverse event (figure 1) (see "Prevention of perioperative medication errors", section on 'Errors resulting in adverse medication events'). In a review of documented IV infusion errors occurring during use of a smart pump in 478 patients (1164 medications), causes included administration of medications not in the pump library (24 percent), bypassing the drug library (10 percent), incorrect infusion rate (5 percent), and failure to include IV fluid necessary to keep the vein open (ie, KVO fluid) in calculations of total infused fluids (5 percent) [10]. However, only four errors in this study were rated as having potential to cause significant harm. An observational study noted similar findings, with only 1 percent of 231 errors occurring in more than 2000 IV medication infusions that could have caused significant harm [9]. In that study, the error rate was similar with or without use of a smart pump.

When programming a pump, checking two values (eg, micrograms per kilogram per minute and rate in milliliters per hour) may help to prevent medication errors. For example, the user might overlook an infusion rate that was set to 1 mcg/kg/minute instead of 10 mcg/kg/minute, but an infusion rate that lasts 36 hours instead of 3.6 hours would be more visible. A detailed discussion of prevention of medication errors occurring in the perioperative setting is provided in a separate topic. (See "Prevention of perioperative medication errors".)

Risks for incompatibility of medications during multiple infusions — It is often necessary to infuse several medications through the same IV catheter, typically a central venous catheter. In such cases, the compatibilities of all infused medications must be considered [11]. Physical incompatibilities may result in precipitation of the active drug, color change, gas production, and particle formation. Any of these issues may significantly reduce the amount of medication administered to the patient [12]. Chemical incompatibilities can lead to drug degradation and the formation of toxic substances. Multi-lumen catheters with up to eight ports have been developed in an attempt to solve such compatibility issues [12].

Risks of infusion in a tucked limb — When the limb containing an IV catheter is tucked at the patient's side table or not continuously visible due to surgical draping, disconnection of the IV tubing from the IV catheter may occur with failure to administer the intended medication. Also, unrecognized IV infiltration and extravasation of a continuous IV infusion into the tissue of a tucked limb may result in compartment syndrome [13,14]. A "high infusion pressure" or "obstruction" alarm indicates the need for rapid inspection of the IV site. Unfortunately, many extravasations result in only modest changes in pressure that do not generate an alarm; thus, a developing compartment syndrome may not be detected.

Cybersecurity risks — Although the ability to connect IV infusion pumps to the electronic health record (EHR) increases available data, provides a decision support resource, and may lead to improved patient outcomes, this interface incurs risks in the absence of stringent cybersecurity measures. Hackers can theoretically steal control of a device to disable hospital networks or cause harm to many patients as part of a bioterrorist attack [15,16]. Ransomware hackers have previously attacked entire hospital systems (eg, the WannaCry ransomware attack in the United Kingdom's National Health Service [NHS]) [17].

Important cybersecurity precautions include access management and cloud storage. However, there are scant data to inform development of comprehensive guidelines and standardized best practice measures [18].

MANUAL FLOW REGULATORS — The oldest way to regulate IV infusions is to manually provide simple, adjustable resistance with a roller clamp on the IV tubing. Another example is use of an incorporated Dial-a-Flow apparatus, which provides a mechanism to change the resistance to flow from partial to complete occlusion by compressing a longer length of IV tubing inside the device. Typically, numbers on a Dial-a-Flow apparatus range from zero to 100, with zero representing complete tubing occlusion, while 100 is the lowest resistance setting allowing for maximum flow. Notably, Dial-a-Flow is an analog device that can be set to an approximate flow rate and changed incrementally.

The user of a manual flow regulator sets a flow rate that is determined by the pressure gradient between the patient and the IV fluid in the bag according to the following formula:

The resultant flow is a function of this pressure gradient, and is also a function of resistance to flow, according to the following formula (figure 2):

If desired, the IV bag can be placed in a manual infuser system that maintains a constant pressure on the bag, which makes the system less sensitive to changes in the height of the table or the height of the fluid in the bag [19]. However, this may increase risk of extravasation if the IV is in a tucked limb. (See 'Risks of infusion in a tucked limb' above.)

Notably, resistance to flow may also be imposed by an IV catheter. If a large-bore IV catheter and tubing are used, the drip chamber imposes approximately the same resistance to flow as that of the IV catheter and the infusion is driven only by gravity. However, if a small-bore IV catheter is used, the catheter itself produces more resistance and becomes the limiting factor.

The approximate flow rate can be determined by counting the drops in the infusion set's drip chamber. Macrodrop and microdrop infusion sets are available, including sets with 10, 15, 20, or 60 drops constituting 1 mL.

Advantages and disadvantages of manual flow regulators include:

●Advantages

•They are simple to assemble and easily adjusted to change the IV tubing resistance to allow increases or decreases in the rate of IV infusion.

•There is no need for batteries, electrical power, or manual programming.

•Low cost and ready availability allows frequent use to control approximate fluid infusion rates in settings where continuous observation is possible (eg, the intraoperative setting).

●Disadvantages

•Gravity-fed administration systems are generally inaccurate because a variety of factors may affect the flow rate, including:

-Changing the height of the bag relative to the patient's heart will change the pressure differential and thereby the flow rate. For example, lowering the operating room table will increase the flow rate.

-As fluid is infused into the patient from the bag, the height of the fluid in the bag decreases, which also decreases the pressure gradient and the flow rate (figure 2).

-The resistance of the drip chamber is important for achieving the range of the infusion set. The diameter of the IV catheter is the rate-limiting component of the infusion set, but also can provide greater resistance and allow less flow than large-bore catheters [19].

One study evaluated drop rates in a variety of infusion sets (macrodrop and microdrop) [20]. Less than 15 percent of observations were within 10 percent of the desired flow rate after initially setting the roller clamp, while only 21 percent were within 20 percent of the desired flow rate. Overall, there were substantial differences between the observed and desired flow rate, indicating that manual regulation is less accurate than infusion pumps.

•A disadvantage for the Dial-a-Flow apparatus is its inability to deliver a calibrated flow rate. The user must understand the limitations of the device as there is a high risk for overdosing or underdosing, potentially causing patient harm. For this reason, manual flow regulators are unsuitable for administration of potent medications such as vasoactive agents (eg, vasopressors, inotropes, vasodilators).

•Infusions administered via any manual flow regulator cannot be left unattended. However, such infusions can be used to control approximate fluid infusion rates in intraoperative settings with continuous observation.

•Accurate documentation of changes in rate of administration of a medication or fluid (eg, in an electronic health record [EHR]) is not possible since flow rates are not monitored. Potential solutions for this problem include devices that monitor the drop rate through the infusion chamber (eg, DripAssist). Such battery-powered devices display the flow in mL/minute, as well as the total volume infused. They may be useful in certain situations (eg, disaster scenarios with a power outage).

SYRINGE PUMPS — Syringe pumps are small infusion pumps that can administer small amounts of fluid at a precise rate set by the user. The accuracy of the pump depends on selection of the correct syringe during pump programming, but most pumps can automatically identify the size of syringe if the user correctly enters the syringe manufacturer name.

Advantages and disadvantages of syringe pumps include [21]:

●Advantages

•Syringe pumps are widely available for use in the perioperative setting to deliver small quantities of fluids or medications (eg, sedatives, general anesthetics, vasoactive agents) at a precise rate.

•Most commercially available devices include integrated safety features such as a drug library. In one study of 133,601 in-hospital medication infusions, the institutional medication library was used to set dose rates for 92.8 percent of syringe pump infusions [22]. The most frequently administered medication classes were vasoactive agents, followed by sedatives [22].

●Disadvantages

•Delays in starting an infusion

-If there is a gap between the syringe driver and the plunger, delivery of the medication to the patient may be delayed. This brief delay may not be clinically significant when an adult is receiving an antibiotic, but may be critical when beginning an urgently needed fluid infusion in a neonate or a vasoactive drug in any pediatric or adult patient. The time from beginning the infusion to reaching a steady-state infusion rate depends in part on the set flow rate (0.1, 0.5, or 1 mL/hour), and in part on the syringe volume size (eg, 10, 20, 30, or 50 mL). Delays as long as 20 to 75 minutes have been noted if the syringe size is large and the set flow rate is low [23,24]. The shortest delays (approximately four minutes) occurred with smaller syringes (eg, 10 mL) and flow rates of at least 1 mL/hour. Clinicians have used "workarounds" for this problem such as doubling the flow rate for a few minutes before connecting the infusion to the patient, but this practice is not recommended as it may result in an overdose if the clinician is distracted and fails to reset the pump to the correct rate.

-A delay may also occur due a hysteresis effect as the pump's motor must turn multiple gears during startup.

•Keyboard entry errors may occur. For example, it may not be clear which units of measurement the user is expected to enter (weight in pounds may be entered when the infusion pump requires weight in kilograms).

•The infusion pump may fail to generate an audible alarm for a critical problem, such as an occlusion (eg, clamped tubing) or the presence of air in the infusion tubing. Conversely, the pump may generate an occlusion alarm in the absence of an occlusion. Also, an alarm indicating low battery charge may not be displayed in time for a user to prevent pump shut-off during a critical infusion while a patient is in transport [21].

•Warning messages may be unclear. An example is the message "Volume in the syringe is inadequate to deliver the programmed dose – PRESS CONFIRM;" it is unclear if the user is confirming the desired infusion settings or his or her understanding of the warning message itself.

ELASTOMERIC PUMPS — Elastomeric pumps have an elastic chamber or balloon that stretches to store energy and pressure (typically 260 to 520 mmHg) as the chamber is filled with the fluid or medication to be administered. The balloon then returns to its original form as it pushes the liquid out through the tubing. The flow controller is used to restrict flow as desired, similar to setting the resistance on a manual flow regulator. (See 'Manual flow regulators' above.)

Elastomeric pumps rely upon the physical characteristics of the balloon to drive the infusion and do not use batteries or any other source of electric power. The figure illustrates the assembly of an elastomeric pump, depicting an initially deflated elastomeric balloon reservoir covered by a hard outside shell that protects the balloon, the filling port, the delivery tube that includes a filter, and the flow controller (figure 3).

Elastomeric pumps were designed to provide ambulatory infusion therapies, such as chemotherapy and postoperative analgesia [25]. They are commonly used for continuous peripheral nerve blockade or IV analgesic agents (eg, methadone, tramadol, dexketoprofen, ondansetron) [26-28].

Advantages and disadvantages of elastomeric pumps include:

●Advantages

•Elastomeric pumps are simple to use and have been associated with fewer human errors during setup and fewer technical difficulties during use compared with other pumps [25,29].

•There is no need for batteries or electrical power.

•For ambulatory patients, specific advantages include:

-Portability for use to deliver postoperative analgesia at home in the immediate postoperative period [28].

-Single-use disposable pumps that can be refilled several times before being discarded, with maintenance of delivery rate and performance after repeated filling [30].

-Infusion duration that may last for several hours up to seven days.

-Overall safety. In one study, fewer than 2 percent of patients receiving home-based analgesic administration had device-related adverse effects or catheter-related complications (eg, phlebitis, extravasation, device dysfunction) [28].

●Disadvantages

•Accuracy and consistency of delivery rate are generally poor. Accuracy is ±15 percent. For example, a pump with a nominal 5 mL/hour actually delivers in the range of 4.25 mL/hour to 5.75 mL/hour [30].

•Variations in actual versus set flow rate may occur due to many factors [27]:

-Initial infusion rates are generally faster than the specified flow rate, as illustrated in the figure (figure 4) [30].

-Actual pressure exerted by the elastomeric balloon is determined by the filling volume.

-Catheters greater than 22 gauge should be used in order to maximize accuracy.

-The vertical height of the pump in relationship to infusion site may send positive or negative back pressure depending on whether the pump is above the IV catheter or wound site (positive pressure) or below this site (negative pressure).

-Flow rate is inversely proportional to the viscosity of the administered fluid. For calibrations of flow, 5% dextrose in water (D₅W) is used.

-Temperature affects elastomeric pump function, with variations from 2 to 3 percent for each 1°C. Devices are most accurate at 92°F or 33.3°C.

-Partial filling of an elastomeric pump can alter the exerted internal pressure and consequently the flow rate [27].

•The amount of drug or total volume delivered cannot be measured, a particular disadvantage in pediatric patients [31].

•There are no alarms on elastomeric devices.

•Degradation of antibiotics within the elastomeric chamber may occur [29,32,33]. Nevertheless, with changes of the elastomeric pump every 24 hours, continuous antibiotic therapy has been administered for 13 days to manage persistent osteoarticular infections, with a reported success rate of 96 percent [30].

SMART PUMPS — So-called "smart" pumps for IV medication infusion ensure that the programmed infusion rate for a given medication is within pre-existing limits using an institutional standardized medication library approved by the institution's pharmacy department. Audiovisual feedback is provided in response to attempted programming outside the predetermined dosing limits or use of incorrect concentrations or duration thresholds. This dose error reduction system (DERS) is programmed with "hard" limits determined by the maximum and minimum safe doses that cannot be bypassed by the user programming the pump.

Smart pumps also have "soft" limits usually determined by the most commonly used infusion rates for a medication. Exceeding a soft limit causes a warning to be displayed noting that the dose is too high or too low, but the user is permitted to proceed with the desired programming and start the infusion after acknowledging the warning. As an example, the figure shows a DERS system, with a mean flow of 10 mg/hour (figure 5) [34]. The normal therapeutic range for the flow is 5 to 30 mg/hour. If 10 mg/hour is not enough, the clinician may bypass the soft upper limit and increase the flow to 40 mg/hour. However, if the desired flow is >60 mg/hour, the pump will not permit the pump to function, as the hard upper limit has been exceeded thereby shutting the pump down. Opportunities for improvement include approaches to minimize "workarounds" that bypass safety limits, but without increasing the number of unnecessary (false) and distracting alarms [7,9]. A recent study of patient-controlled analgesia (PCA) pumps concluded that device-related errors are relatively uncommon, occurring in less than 0.2 percent of patients, and that the most common error is underflow, resulting in inadequate analgesia. The authors found no instances of patient mortality [35].

In practice, the safety and efficacy of smart pumps depends primarily on the operator's use of the medication library incorporated within the pump, and acceptance of the suggested dosing limits for most patients (rather than manual programming that is possible to bypass these safeguards) (figure 6) [3,4,7]. Most smart pumps can be programmed to revert to a "basic" mode (eg, mL/hour). Clinicians may be tempted to use this mode because it is familiar, but doing so bypasses the safety features incorporated in the drug library.

In the operating room, smart pumps are frequently used to administer potent anesthetics and vasoactive medications (eg, vasopressors, inotropes, vasodilators). These agents must be continuously titrated to achieve the desired effect. Ideal features for a smart infusion pump in the perioperative setting include operator ability to rapidly change the flow rate with minimal keystrokes. For example, nine or more characters may be required for entry of the patient's identification number and other information such as weight, followed by multiple keystrokes to enter the medication name, concentration, and desired initial dose. Error rates increase with the number of required keystrokes [7]. In some perioperative circumstances, adjustment of the flow rate to provide doses that are outside the device's preprogrammed limits may be necessary. However, in all such instances, appropriate warnings should be displayed on the device.

Advantages and disadvantages of smart pumps include [7]:

●Advantages

•The potential to detect and prevent serious medication errors and improve patient safety. In a 2014 systematic review, use of smart pumps reduced programming errors but did not eliminate them [7]. This study found that compliance with drug libraries and smart pump limits was the best way to prevent drug errors. Drug library hard limits were the most effective way to minimize medication errors, while soft limits were not as effective because users override them.

•Inclusion of features that can usually identify the source of medication errors due to retention of a log of all alerts. In one study, smart pump alert data were collected to determine which medications were associated with the most and least clinically meaningful pump alerts [36]. These data were then used to optimize the drug library limits and also to decrease clinician "alert fatigue". (See "Safety in the operating room", section on 'Techniques to minimize distractions and disruptions'.)

•Other technology to detect problems such as occlusion, infiltration, siphoning, and air bubbles in the IV fluid is incorporated within such devices [37].

•Inclusion of a barcode-assisted medication administration scanning system is possible [38]. Scanning of barcodes may include those on medications, the patient's wristband identification, and the clinician's identification badge.

●Disadvantages

•Possible errors include:

-Pump setting errors that may go undetected (eg, wrong rate, wrong dose, wrong concentration, wrong medication)

-Use of the wrong medication library

-Overriding soft limits

-Compliance issues (ie, workarounds)

•The medication library cannot contain every medication that may be used in the intraoperative setting, or may contain only very narrow parameters for a given medication, so that manual programming may be necessary. In such cases, the user must take extra care to ensure that the infusion rate is correct.

•Limits are set for typical patients. It is not possible to predict the needs of every patient and clinical circumstance. For this reason, many IV smart pumps allow the users to bypass the DERS low end limits and use manual programming as needed. However, this ability to bypass the pump may also be a disadvantage that can cause medication errors in some instances.

•Smart pumps are not assigned to individual patients and are not associated with intended therapy for an individual patient. Thus, they cannot intercept wrong patient medications or prevent wrong drug selection.

•Implementation of the use of smart pumps throughout an institution requires consolidation of the hospital medication formulary and elimination of use of unapproved abbreviations. Typically, there is a necessary "learning curve" for clinicians during initial clinical use. Nevertheless, follow-up at one year after implementation noted a reduction in pump-related dosing errors from 41 to 22 percent in one study, with more minor reductions in wrong dose and incorrect infusion rate errors [39].

TARGET-CONTROLLED INFUSION SYSTEMS — Target-controlled infusion (TCI) systems are computer-assisted IV infusion pumps that use pharmacokinetic and pharmacodynamic mathematical modeling to maintain a user-designated target concentration at an effect site (typically the brain) [40,41]. With TCI systems, the clinician enters a desired target concentration for an anesthetic or other agent. The computer calculates the amount of the agent required to achieve the target concentration at the effect site, and directs an infusion pump to deliver the calculated boluses or infusions. Subsequently, the computer constantly recalculates how much drug is in the tissues and how that influences the amount of drug required to achieve the desired target concentration at the effect site. Calculations include the drug's pharmacokinetics as well as patient covariate data (eg, age, weight).

Mathematical modeling for TCI infusions must account for redistribution and elimination of the medication into multiple compartments. A three-compartment model is typically used (figure 7) [42]. The central compartment (V1) represents the plasma concentration as the pump injects the medication intravenously, and one peripheral compartment is largely comprised of fat tissue (V2), while the other peripheral compartment represents lean tissue concentration (V3). Calculations of rate and direction of drug movement among these compartments occur continuously throughout the period that the medication is administered in order to maintain a targeted effect site concentration.

In general, a TCI pump will initially deliver a bolus dose to rapidly achieve the desired end-organ concentration, followed by administration of an infusion or smaller bolus doses to maintain the target concentration. A TCI system typically reduces the infusion rate gradually over time, based on its calculations. These concepts are intuitive for anesthesiologists since they are similar to techniques used for delivery of inhalation anesthetics to achieve a desired end-tidal concentration, with a corresponding brain concentration of the anesthetic after equilibration has occurred. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Induction of general anesthesia' and "Inhalation anesthetic agents: Clinical effects and uses", section on 'Maintenance of general anesthesia (all inhalation agents)'.)

In the perioperative setting, TCI techniques have been used to induce and maintain general anesthesia or to provide computer-assisted personalized sedation [41,43,44]. However, TCI devices have not been approved in the United States [43,45,46].

Advantages and disadvantages of TCI systems include:

●Advantages

•Theoretically, TCI allows predictable induction and maintenance of general anesthesia or sedation, as well as predictable recovery from anesthetic effects when used in appropriate patients and settings [6,47-54].

•Improvements in performance and safety of TCI systems are likely with incorporation of closed-loop controls based on monitoring of pharmacodynamic end-points such as processed electroencephalographic (EEG) parameters or changes in the hemodynamic profile (eg, mean arterial pressure and heart rate) [6,48,49,52,55-57]. Such pharmacodynamic monitoring could supplement TCI pharmacokinetic modelling of effect-site concentrations. Closed loop systems are being developed that require continuous measurement of a biosensor output (eg, EEG), with continuous adjustments of the infusion rate to maintain a target value.

●Disadvantages

•Intersubject variability in the pharmacokinetic and pharmacodynamic parameters used in models to calculate the drug concentration at the effect site has limited the utility of TCI systems [6,44,47,58,59]. In particular, the following patient covariates affect modeling:

-Obesity is commonly associated with higher than anticipated plasma concentrations of propofol and other agents with use of standard models for TCI pumps [58,60,61]. Models that incorporate obesity are accurate only in obese patients, but risk underdosing for non-obese patients [60].

-Underweight individuals may experience either underdosing or overdosing with available models [62].

-Children may have different pharmacokinetic and pharmacodynamic profiles than adults. Use of TCI for propofol anesthetic administration can lead to higher propofol dosing in pediatric patients, with or without prolonged recovery time [42,63,64].

-Most TCI models do not compensate for patient comorbidities [6,65].

-Most TCI models do not compensate for drug-drug interactions or synergy when multiple medications are administered [6].

•Development of multiple pharmacokinetic models for each anesthetic agent in previous research studies of TCI system use has limited the clinical utility of these systems [44,48,66]. In the future, selection of the appropriate model for different patient groups (eg, obese patients, pediatric patients) will likely be automatic during device programming for an individual patient [44,45].

LIKELY FUTURE DEVELOPMENTS — Continuing developments to improve safety for intraoperative IV infusion technology include clinical integration with the anesthesia information management system, thereby incorporating use of clinical monitoring devices (pulse oximeter and capnography). For example, in an awake patient, if oxygen saturation decreases or carbon dioxide increases beyond certain preset limits during infusion of a medication such as an opioid or sedative agent, the infusion pump(s) would automatically stop, and alarms in the system would be activated [67].

The next generation of infusion management systems may be able to directly interface with the patient's electronic health record (EHR) and computerized physician order entry (CPOE) system, ideally with barcode-assisted medication administration. These wireless bidirectional connections will allow decision support for preprogramming of IV infusion devices to minimize risk of errors, including calculation of appropriate infusion rates based on factors such as patient weight and known standardized drug concentrations in an institution's premixed infusions [40,68,69]. In addition, electronic transmission of infusion information obtained from the pump will occur automatically to document titrations of infusion rates, thereby allowing continuous recording of medication dosing within the EHR [5,40]. The resulting electronic medication administration records would be used to target errors that occur in drug-dispensing transcription and administration within an institution. (See "Prevention of adverse drug events in hospitals", section on 'Electronic medication administration record' and "Prevention of adverse drug events in hospitals" and "Prevention of perioperative medication errors", section on 'Clinical decision support'.)

Other likely future developments include:

●Elimination of most false ("nuisance") alarms that may decrease users' sensitivity to all alarms.

●Improvements in pharmacokinetic modeling and supplemental pharmacodynamic monitoring for target-controlled infusion (TCI) systems. (See 'Target-controlled infusion systems' above.)

●Systems that take advantage of alternate routes for medication administration (rather than IV delivery). Examples include intranasal, pulmonary, buccal mucosal, and intra-articular controlled-release drug therapy, as well as transdermal medication delivery systems [70].

●Site-specific medication delivery alternatives. An example is delivery of flow-sensitive nanoparticles coated in tissue plasminogen activator (tPA) that can release tPA at the site of a clot [70].

SUMMARY AND RECOMMENDATIONS

●Strategies to mitigate risks during perioperative use of intravenous (IV) infusion devices include:

•(See 'Risks for medication errors' above.)

•(See 'Risks for incompatibility of medications during multiple infusions' above.)

•(See 'Risks of infusion in a tucked limb' above.)

•(See 'Cybersecurity risks' above.)

●The oldest way to regulate IV infusions is to manually provide adjustable resistance with a roller clamp on the IV tubing or an incorporated Dial-a-Flow apparatus. Advantages of these manual flow regulators include simplicity and easy adjustability to allow changes in IV infusion rate; absence of need for batteries, electrical power, or manual programming; low cost; and ready availability. Disadvantages include the variety of factors that affect the flow rate (eg, changing the height of the bag relative to the patient's heart or the height of the fluid in the bag as fluid is infused, diameter of the IV catheter). Other disadvantages include inability to deliver a calibrated flow rate, leave the IV infusion unattended, or accurately document changes in rate of fluid administration. (See 'Manual flow regulators' above.)

●Syringe pumps are small infusion pumps that have the ability to administer small amounts of medication or fluid at a precise rate set by the user. Other advantages include integrated safety features such as a drug library. Disadvantages include delays in starting an infusion due to any gap between the syringe driver and the plunger and a hysteresis effect as the pump's motor turns to start multiple gears during startup. (See 'Syringe pumps' above.)

●Elastomeric pumps have a balloon that stretches to store energy and pressure as the chamber is filled with fluid, then returns to its original form as it pushes liquid out through the tubing. The flow controller is used to restrict flow as desired. Advantages include ease of use with fewer human errors during setup and fewer technical difficulties compared with other pumps, as well as absence of need for batteries or electrical power, and portability for use at home (eg, to deliver postoperative analgesia). Disadvantages include poor accuracy and inconsistent flow rate since many factors may cause variations in actual versus set flow rate. (See 'Elastomeric pumps' above.)

●"Smart" pumps ensure that the programmed infusion rate for a given medication is within the preset limits of a standardized medication library. Advantages include the potential to detect and prevent serious medication errors, as well as incorporated technology to detect problems such as occlusion, infiltration, siphoning, and air bubbles in the IV fluid. Disadvantages include dependence on the operator's compliance with institutional medication library limits and correct use of the pump in an individual patient. (See 'Smart pumps' above.)

●Target controlled infusion (TCI) systems are computer-assisted IV infusion pumps that use pharmacokinetic and pharmacodynamic mathematical modeling to maintain a user-designated target concentration at an effect site (typically the brain). Theoretical advantages include predictable induction and maintenance of general anesthesia or sedation, as well as predictable recovery from anesthetic effects. Disadvantages limiting utility of TCI systems include intersubject variations (eg, overweight or underweight status, comorbidities, age) that affect pharmacokinetic and pharmacodynamic parameters used in models to calculate drug concentration at the effect site, and the need to compensate for drug-drug interactions or synergy when multiple medications are administered. (See 'Target-controlled infusion systems' above.)