The "Hypotension Prediction Index" in Patients Undergoing Lung Surgery
The "Hypotension Prediction Index" in Patients Undergoing Lung Surgery
The "Hypotension Prediction Index (HPI)" was established by the Edwards Lifescience Company
 (Irvine, California, USA) and is CE certified. As part of the Edwards Acumen
 Decision-Support-Software-Suite the HPI is supported by the minimal invasive FloTrac Sensor.
 The HPI displays the probability of an occurring hypotension. The software was established
 with the help of 20.000 analyzed patient events. If the upper limit of the HPI is reached,
 the software is alarming the treating physician 8. At the university hospital of Giessen HPI
 analyses are used in the daily clinical routine as well as for scientific purposes.
 Preliminary data of the HPI-I-Trial ("Influence of the Hypotension Prediction Index on the
 number and duration of intraoperative hypotension in primary hip-endoprothetic replacement",
 University Hospital of Giessen) included patients, which underwent hip-endoprothetic
 replacement surgery and revealed that the use of HPI with a goal directed therapy (GDT)
 protocol compared to standard care significantly reduced the incidence and duration of
 intraoperative hypotension. Therefore HPI with GDT might reduce the incidence of hypotension
 related complications in a sicker patient cohort.

 The aim of the study is to investigate whether a goal directed treatment according to the
 Hypotension Prediction Index compared to standard care can reduce the incidence of
 intraoperative hypotension in patients under single lung ventilation.
Monitoring of blood pressure is a basic tool to assess the patients' hemodynamic status.
 Physiological blood pressure is usually close to 120/80 mmHg. Hypotension is not clearly
 defined as shown in previous studies 1, 20, 21. Some studies defined hypotension as a
 systolic blood pressure below 100 mmHg or a mean arterial pressure below 60 mmHg 1,2.
 Depending on the definition intraoperative hypotension (IOH) hypotension can occur in 38% of
 patients undergoing non-cardiac surgery. 53% of these patients die within one year. Monk et
 al. noted that the 1-year-mortality was raised by 3.6% for every minute the systolic blood
 pressure was below 80 mmHg. The risk of mortality was raised up to 1.4 times when the MAP was
 under 55 mmHg for more than 10 minutes 3. Additionally, in 2015 it was shown that even short
 duration of MAP under 55 mmHg is associated with a high risk for acute kidney injury and
 myocardial infarction 4. A recent definition of hypotension was published by of Vernooij et
 al. that defined IOH as a decrease of MAP < 65 mmHg for more than one minute in this study
 22. Perioperative hypotension is a complication that can occur in the induction period and in
 the following phase. Recent unpublished data from the Sessler group presented at the 2018 ASA
 meeting in San Francisco showed that about 1/3 of hypotensive episodes are unrelated to
 surgery as those occur before the surgeon is in the OR 28. The reasons for hypotension can be
 found in vasodilatation (e. g. drug induced), volume deficit (based on blood loss), or
 negative inotropic effect of surgery and anesthetic drugs (reduced left ventricular
 function). Main factors causing intraoperative hypotension according to literature are age,
 preexisting diseases (especially ASA > 3), duration of surgery, acuteness of surgery
 (emergency), anti-hypertensive medication and anesthesia combining general and regional
 anesthesia 5,6. Complications related to hypotension can be detected in most organ systems.
 One important source of hypotension-associated complications are cardiovascular
 complications. Recently, a syndrome that was termed myocardial injury after non-cardiac
 surgery (MINS) was shown to be associated with hypotension and lead to increased
 postoperative mortality rate 23, 24. Acute kidney injury (AKI) affects up to 25% of patients
 in the intensive care unit 7. Liu et al. described that an episode of relative hypotension is
 often followed by AKI (a decrease in systolic blood pressure relative to pre-morbid value was
 a significant independent predictor of the development of AKI and of RIFLE classes I and F;
 odds ratio 1.084 for every -1 mmHg change in systolic blood pressure) 8. As stated,
 'normotensive renal failure' is not common and a rare phenomenon in the absence of septic and
 other complications. This results are supported by other publications, like Lehmann et al. 9.
 Their results indicate that the risk of AKI was related to the severity of hypotension with
 an odds ratio (OR) of 1.03, 95% CI 1.02-1.04 (p < 0.0001) per 1 mmHg decrease in minimum MAP
 ≥ 80 mmHg. For each additional hour MAP was less than 70, 60, 50 mmHg, the risk of AKI
 increased by 2% (OR 1.02, 95% CI 1.00-1.03, p = 0.0034), 5% (OR 1.05, 95% CI 1.02-1.08, p =
 0.0028), and 22% (OR 1.22, 95% CI 1.04-1.43, p = 0.0122).

 Renal failure poses a relevant complication in the perioperative phase 5, 6. Over the last
 decade the cell cycle arrest biomarkers TIMP-2- and IGFBP7-quantification (Nephrocheck) has
 been successfully evaluated for the detection of AKI 7. The main advantage of both parameters
 is the opportunity of early detection of AKI and its point-of-care design, which makes them
 especially for the use on the intensive care unit valuable. Based on these facts, the
 predictive measurement of blood pressure is of great interest for the anesthesiologist to
 optimize patients' postoperative outcome.

 The "Hypotension Prediction Index (HPI)" was established by the Edwards Lifescience Company
 (Irvine, California, USA) and is CE certified. As part of the Edwards Acumen
 Decision-Support-Software-Suite the HPI is supported by the minimal invasive FloTrac Sensor.
 The HPI displays the probability of an occurring hypotension. The software was established
 with the help of 20.000 analyzed patient events. If the upper limit of the HPI is reached,
 the software is alarming the treating physician 8. At the university hospital of Giessen HPI
 analyses are used in the daily clinical routine as well as for scientific purposes.
 Preliminary data of the HPI-I-Trial ("Influence of the Hypotension Prediction Index on the
 number and duration of intraoperative hypotension in primary hip-endoprothetic replacement",
 University Hospital of Giessen) included patients, which underwent hip-endoprothetic
 replacement surgery and revealed that the use of HPI with a goal directed therapy (GDT)
 protocol compared to standard care significantly reduced the incidence and duration of
 intraoperative hypotension. Therefore HPI with GDT might reduce the incidence of hypotension
 related complications in a sicker patient cohort.

 The development of modern lung surgery started in the 19th century. Especially in Germany
 Rudolf Nissen (first pneumonectomy, 1931) and Ferdinand Sauerbruch were the first pioneers of
 lung surgery. With enhancement and refinement of thoracic anesthesiology (lung separation)
 and further specialization of surgery, thoracic surgery became a seperate discipline. During
 thoracic surgery lung separation and isolation with accomplished single-lung ventilation
 plays a key role in the development of thoracic surgery. Spectrum of indication contains
 thoracic surgery, procedure- and patient-dependent factors. Usually lung isolation is
 achieved with a double-lumen tube or a bronchial blocker. Major domain of thoracic surgery is
 nowadays oncological surgery of lung cancer. With modern imaging lung cancer is detected in
 early stage, so more operations can be performed. Additional in the last thirty years more
 and more minimal invasive procedures (VATS) were performed which result in gentle and
 successful treatment of thoracic surgical patients.

 Beside oncological surgeries (which make almost 50% of all procedures in thoracic surgery)
 plays surgery of inflammable diseases and pulmonary emphysema a major role.

 Approximately 182.821 thoracic surgical procedures are performed in Germany, 11.451 in
 Hessen. At the university clinic institution of Giessen more than 500 procedures are
 performed per year.

 Hypotension Prediction Index The "Hypotension Prediction Index (HPI) "was established by the
 Edwards Lifescience Company (Irvine, USA) and is CE certified. The HPI displays the
 probability of an occurring hypotension before its onset and therefore can theoretically
 prevent episodes of hypotension by guiding earlier therapy. This might improve outcome in
 certain patient populations by preventing episodes of hypotension 29. A recent paper
 describes the methodology of this prediction tool 25.

 Nephro Check NephroCheck is a point of care urine test that flags two biomarkers that
 indicate if a critically ill patient is at risk for acute kidney injury (AKI) 15. Currently,
 serum creatinine is the main test used to detect AKI, but it may take a day or more for serum
 creatinine levels to accumulate in the blood of a patient with a kidney injury consequently,
 it may not reflect real time kidney damage or loss of function 16. Results of the NephroCheck
 test are available within 20 minutes before clinical signs of kidney failure are apparent.
 The evidence suggests that the NephroCheck test has good sensitivity (89% at the 0.3 cutoff
 value) for detecting critically ill patients at risk for AKI 17, 18.

 The aim of the study is to investigate whether a goal directed treatment according to the
 Hypotension Prediction Index compared to standard care can reduce the incidence of
 intraoperative hypotension in patients under single lung ventilation.
Inclusion Criteria:

 -  Patients undergoing lung surgery with one-lung-ventilation

 -  General anesthesia

 -  Age ≥ 18 years

 Exclusion Criteria:

 -  Participation in another (interventional) study

 -  Pregnancy and nursing mothers

 -  Surgery without controlled ventilation

 -  ASA I or IV

 -  Contraindication for invasive blood pressure monitoring

 -  Coagulation disorder

 -  Arterial Fibrillation