fig1 - 3 show embodiments of the invention wherein intravenous fluid delivery may be automated , or manually adjusted , based on feedback from one or more sensors . in these embodiments , the infusion catheter may have a sensor to aid in insertion , but this is not necessary for this invention . in one embodiment , the infusion catheter also is used to detect the parameters used to optimize therapy . fig1 shows an infusion system with an infusion controller 10 operably connected to an intravenous infusion catheter 12 via an infusion line 14 . infusion catheter 12 also has a sensor ( not shown ) attached to or associated with it to monitor a patient parameter . the sensor also communicates with controller 10 either through line 14 or via some other communication channel . suitable patient parameters include electrocardiograph monitoring , electroencephalograph monitoring , pulse oximetry ( either internally or peripherally ), blood pressure , central venous pressure , cardiac output , cardiac stroke volume , cardiac rate , blood flow ( e . g ., in superior mesenteric , celiac , renal or other arteries ), total circulating blood volume , pressure in veins ( particularly those that empty into the inferior vena cava , e . g ., femoral vein ), pressure in arteries ( particularly those distal to the aorta , e . g ., the femoral artery ), blood oxygenation ( e . g ., in rectal mucosa , peripheral fingers and toes , etc . ), whole body oxygen consumption , ph , arterial po 2 , or any other parameter that shows a measurable change with intravascular volume overload . as shown in fig1 , additional catheters , here envisioned as a peripherally inserted central catheter ( picc ) 16 and / or a peritoneal catheter 18 , or additional sensors on infusion catheter 12 may be used to monitor these or other parameters , and to optimize the infusion rate and achieve euvolemia without fluid overload or dehydration . flow of fluid and or a fluid solid mixture ( e . g ., an ice slurry ) to catheters 16 and / or 18 is controlled by controller 10 through lines 14 , 15 and / or 17 , respectively . the information from the sensors may then be transmitted to central controller 10 , which integrates all of this information to determine the flow of intravenous fluid through catheter 12 and / or catheter 16 and flow of peritoneal fluid through catheter 18 . this information may be used to achieve or maintain euvolemia ( e . g ., in sepsis , hemorrhagic shock , etc .) or to maximize infusion for delivery of a therapeutic agent , e . g ., chilled fluid and / or solids to achieve hypothermia . alternatively , catheters 16 and 18 may be used with sensors to obtain patent information , and fluid may be infused into the patient solely through catheter 16 or catheter 18 . in yet further embodiments , the depth of hypothermia and / or rate of hypothermia induction or rewarming may be tailored based on intracranial pressure sensor ( s ) ( not shown ) communicating with controller 10 via communication line 35 . this system and method may be used with any method of inducing hypothermia ( e . g ., cooling blankets , intravascular catheters , intravenous fluid infusion , peritoneal lavage , etc .) so long as the change in temperature , particularly rewarming , is controlled at least in part by an intracranial pressure sensor . the sensor or sensors , whether cables / catheters or percutaneous monitoring technologies , and whether wired or wireless , may also be separate from the infusion line so long as the information from this sensor or sensors is transferred to the control unit in order to optimize fluid flow . thus , as shown in fig2 , the patient parameter sensor may be associated with picc 24 and communicate with controller via line 26 , and infusion to the patient may be via line 22 and infusion catheter 20 , as controlled by controller 10 . in some embodiments , of course , sensing and infusion may be performed through a single catheter , such as picc 30 , and controlled by controller 10 through lines 32 and 34 , as shown in fig3 . in some embodiments , the infusion and monitoring device of the current invention may incorporate an access sensor , such as that described in a commonly owned patent application , u . s . patent application ser . no . 12 / 098 , 355 , filed apr . 4 , 2008 , titled “ device and method for safe access to a body cavity ”. one example of such a device is a peripheral venous , central venous or arterial catheter that is capable of maintaining hydration without causing fluid overload . the catheter may incorporate a sensor that may detect central venous pressure , total circulating blood volume , peripheral venous pressure , cardiac output or osmolarity , and / or solute concentrations e . g ., chloride , sodium , etc .) in order to prevent fluid overload . the sensor may also be external to catheter , so long as the output of said sensor is capable of controlling fluid flow through the catheter . in this embodiment , fluid flow is controlled by the output of the sensor , which is integrated by a fluid flow control unit which alters the rate of fluid flow based on this output . this embodiment may allow the user to bolus large volumes of fluids or solids into the vascular space in order to rehydrate , induce hypothermia or reverse hypothermia , or deliver a therapeutic agent or maintain blood pressure in sepsis . in addition , this technology may provide a fully automated mechanism to optimize fluid flow into the vessel without fluid overloading the patient . without this automated fluid delivery coupled to hemodynamic parameter monitoring , the patient is in danger of dehydration or fluid overload from infusion of fluid into any body cavity . this technology may also be applied to liquid or solid infusion into any body cavity or space in so long as the fluid flow is automated based on feedback from sensors within the body ( possibly incorporated into the catheter itself ) in order to optimize the volume of infusion . this device and method of automating fluid flow based on hemodynamic sensor - based feedback may also be used to generate intravenous hypothermia . in its current state , iv hypothermia induction is limited due to concerns of fluid overload . if the hemodynamic parameters of the patient can be measured and fluid flow directly or indirectly controlled based on the output of these measurements , the volume of fluid can be maximized while ensuring hemodynamic instability . in this embodiment , the sensor may be incorporated within the catheter , and fluid flow into the vasculature may be tailored based on central venous pressure , total circulating blood volume , peripheral venous pressure , cardiac output or osmolarity , and / or solute concentrations ( e . g ., chloride , sodium , etc .) in order to prevent fluid overload . in one embodiment , the fluid infusion catheter also may function as a thermodilution cardiac output sensor such that the same fluid that is used to generate hypothermia may also be used to detect cardiac output . this information may then be relayed , either directly or indirectly , back to the fluid infusion controller to increase , decrease or even halt fluid flow based on these parameters . for example , if cardiac output is low and venous pressure or total circulating volume is low , the patient has a low circulating volume and large volumes of fluid may be safely delivered . if the cardiac output is normal , fluid may also be safely delivered , but the cardiac output must be monitored to ensure that it does not begin to decrease ( an indication of fluid overload ). blood flow , as detected by , for instance , thermodilution may be determined in a peripheral vessel as well . these data , while relatively useless on their own in a clinical setting due to variability in peripheral blood flow , may provide a baseline flow profile which may be rechecked over time in order to compare flow within that individual vessel to the baseline flow . relatively improved flow may be correlated to improved cardiac output , while a relative reduction in flow may be correlated to fluid overload . this same system may be used to infuse normal fluids or hypothermic fluids to sepsis patients or patients requiring intensive maintenance of their hemodynamic status . sepsis patients that are aggressively monitored do much better than those that are not . aggressive monitoring is very nurse - intensive , however . a system that provides automated optimal fluid infusion based on sensed parameters to ensure that fluid overload does not occur and that fluid infusion is not insufficient would be an improvement over current methods of treating sepsis patients . the devices and methods for automated sensor - based input to control fluid flow to a patient may be applicable to a wide range of conditions and should not be limited to the narrow scope of the conditions requiring fluid infusion described here . the logic controller of the present invention may provide improved safety by monitoring for any of the deleterious changes expected with excess fluid flow , e . g ., into the peritoneal cavity or vascular space . examples of monitored parameters that may signal a warning or automatically result in an adjustment to rate of fluid infusion / extraction and / or fluid temperature include : electrocardiograph monitoring , electroencephalograph monitoring , pulse oximetry ( either internally or peripherally ), peritoneal cavity compliance , intrathoracic pressure , intraperitoneal pressure , intraperitoneal pressure waveforms , bladder pressure , rectal pressure , cardiac output , cardiac stroke volume , cardiac rate , total circulating blood volume , blood flow ( e . g ., in superior mesenteric , celiac , renal or other arteries ), pressure in veins ( particularly those that empty into the ivc , e . g ., femoral vein ), pressure in arteries ( particularly those distal to the aorta , e . g ., the femoral artery ), blood oxygenation ( e . g ., in rectal mucosa , peripheral fingers and toes , etc . ), whole body oxygen consumption , ph and arterial po 2 and any other parameter that shows a measurable change once the peritoneal or vascular spaces have been overloaded . these parameters in particular have been found to change with increases in peritoneal pressure , with significantly negative impact on each parameter found at 40 mmhg . thus , monitoring for these changes in conjunction with a peritoneal infusion catheter of the present invention will allow for even greater safety with peritoneal infusion . these parameters may be measured a variety of ways and the data transmitted either wirelessly or via wires to the logic controller in order to alert the healthcare provider or to automatically adjust the fluid flow / temperature in order to optimize both the flow of the peritoneal fluid and patient safety .
an automated therapy system having an infusion catheter ; a sensor adapted to sense a patient parameter ; and a controller communicating with the sensor and programmed to control flow output from the infusion catheter into a patient based on the patient parameter without removing fluid from the patient . the invention also includes a method of controlling infusion of a fluid to a patient . the method includes the following steps : monitoring a patient parameter with a sensor to generate a sensor signal ; providing the sensor signal to a controller ; and adjusting fluid flow to the patient based on the sensor signal without removing fluid from the patient .