Dr. med. Leon Schmidt (Mainz / DE), Dr. Michael Kosterhon (Mainz / DE), PD Dr. med. Darius Kalasauskas (Mainz / DE), Prof. Dr. med. Florian Ringel (Mainz / DE), Dr. med. Thomas Kerz (Mainz / DE)
Abstract-Text (inkl. Referenzen und Bildunterschriften)
Objective
Airway Pressure Release Ventilation (APRV) is an alternate mode of ventilation in Acute Respiratory Distress Syndrome (ARDS), but there are inconsistent data to support its use. Because of increased intrathoracic pressure for most of the respiratory cycle, a negative impact on intracranial pressure (ICP) has been hypothesized. [1] We aimed to evaluate the impact on APRV on Horovitz index, ICP, Cerebral Perfusion Pressure (CPP), Mean Arterial Pressure (MAP), and Therapy Intensity Level (TIL).
Methods
Retrospective single-center analysis from January 2021 to March 2023 of neurosurgical ICU patients with ICP probes inserted. APRV was used as a rescue mode when the Horovitz index fell below 150 mmHg despite optimized ventilation.
Results
This study enrolled 28 patients undergoing 31 episodes of APRV. Median age was 56 (IQR 44-62) years, 12 (38.7%) were female. The main diagnosis was intracerebral hemorrhage (11, 35.5%), subarachnoid hemorrhage (7, 22.6%), traumatic brain injury (4, 2.9%) and other (9, 29%).
Before conversion to APRV, compliance was 38 (IQR 23-55) ml/cmH2O, Horovitz index 144 (IQR 136-160) mmHg, ICP 12 (IQR 5-17.5) mmHg, cerebral CPP 78 (IQR 62-84) mmHg (all median). The TIL was 0 in 5 (16.1%), 1 in 12 (38.7%), 2 in 11 (35.5%) and 3 in 3 (9.7%) cases.
Following conversion to APRV, there was a rise in the median Horovitz index (60min: 201,44|120min: 208,61 mmHg), indicating enhanced oxygenation. Additionally, there was a tendency towards a lower ICP (60min: 9,5|120min: 11 mmHg) with an increase in CPP (60min: 80|120min: 77 mmHg, all median). Differences, apart from CPP after 45 minutes (p=0.011), did not attain statistical significance. One-hour post-transition, TIL significantly decreased (Z=-2.4, p=0.008); yet there were no differences after two hours. No critical increases in ICP (>20 mmHg) were observed. No instances of pneumothorax, acute renal failure or myocardial injury was observed. ICP, MAP, CPP values and Horovitz Quotient are displayed in Figure 1.
Conclusion
APRV did not increase ICP or decrease CPP. TIL decreased in the first hour. The Horovitz index showed an increase after the use of APRV. APRV was safe regarding effects on ICP, MAP, and CPP and appears to be a possible ventilatory strategy in this patient population.
Fig 1- ICP, MAP, Horovitz-Quotient and CPP before and after transition to APRV.
1Marik P.E., et al. The effect of APRV ventilation on ICP and cerebral hemodynamics. Neurocrit Care, 2012.