Evaluation of the Effect of Endotracheal Suctioning Applied at Different Head Height on Oxygenation of the Brain by Non-Invasive Method in Intensive Care Patients

Although the brain is only 2% of body weight,it is the most metabolically active and vital organ of the body.Cells in the brain; they need higher amounts of oxygen and energy than other organs in the body. Therefore, in order to maintain brain functions,rich and continuous blood flow and optimal oxygen saturation are required. Cerebral blood flow(SKA) is the most important factor in nutrition that provides oxygen saturation. Cerebral blood flow;Cerebral perfusion pressure(SPB) is affected by mean arterial pressure(MAP) and intracranial pressure(KIB).Under normal conditions, while SPB is constant, the conditions affecting blood pressure and cerebral venous return and elevation of KIB affect SPB.While normal cerebral blood flow is 50-70 ml/100 g/tissue/min;In cases where blood flow is interrupted,serious flow disruptions occur in cerebral circulation when the flow rate drops below 20 ml and vital conditions such as cerebral ischemia occur.

In cerebral blood flow intensive care patients;it may be disrupted during some maintenance procedures that cause painful stimuli such as position change,head height,endotracheal suctioning,oral care, and invasive procedures.In the literature;It is reported that if the cerebral blood flow drops below 20 ml/100 g/min for 30 minutes,it will reversibly stop the function of neurons,and if it falls below 10 ml/100 g/min for 30 minutes, irreversible neuron damage will occur.Therefore, in order to prevent unwanted cerebral ischemia in intensive care patients;Before each procedure applied to the patient, the amount of oxygen in the bloodstream circulating in the brain tissue should be constantly monitored. In the last guide published by the Brain Trauma Association;It is recommended that partial carbon dioxide pressure(PaCO2) is 35-40 mmHg, partial oxygen pressure(PaO2) is above 60 mmHg, and arterial oxygen saturation is 90% and above.In order to preserve these values, the patients are followed up in the mechanical ventilator for a while in the first period they exit the operation.

While the fact that the patients are connected to the mechanical ventilator may provide advantage in terms of providing continuous oxygenation,it may bring additional risks for the patients. Because the endotracheal suctioning suctioning need arises in the patient in the mechanical ventilator.There are important risks of endotracheal suctioning of mechanically ventilated patients with artificial in patients receiving mechanical ventilator support to prevent hypercarbia and hypoxia caused by secretion accumulated in the respiratory tract.These risks include hypoxia, arrhythmia, increase in MPD,hypertension,hypotension,agitation,pain,etc. countable.Especially during endotracheal suctioning, the increase of intracranial pressure in the patient, then the cough reflex induced and the high course of intracranial pressure after suctioning will disrupt cerebral perfusion,thus oxygenation of the brain is endangered.While blood flow and perfusion may be normal before and during the procedure,it changes to critical value afterwards and if it lasts more than 30 minutes,it poses a threat to patients.The position of the patient and the length of stay in the same position affect the cerebral circulation,reducing SPB.In this case,if the nursing follow-ups are insufficient or the attempts to protect the SME are ineffective;it becomes difficult for the brain to perform its functions, and even becomes unable to perform.

In the intensive care units,raising the head and positioning is a routine nursing initiative in order to protect patients from KIB and cerebral complications that may occur due to KIB.Different head heights and body positions applied after the neurosurgical intervention have been observed to affect secondary complications by affecting SME, PB and SKA.According to researches; lateral position given by raising the head of the bed, long-term flexion and extension of the head, the head being constantly 45° high are positions that may be harmful for neurosurgical patients.In addition, it has been reported that rotating or repositioning causes more secondary brain damage(7%) by increasing the ICU compared to other nursing interventions applied to patients. Secondary brain damage may result from 5 minutes after nursing interventions or more than 10 minutes from the beginning of nursing intervention,20 mmHg above KIB,60 mmHg below SPB,and 100 mmHg below systolic blood pressure. Responsibility of neurosurgical nurses;It is the safest way to provide the care that the patient needs without experiencing any undesirable side effects and secondary complications (respiratory events,cerebral ischemia,increased ICP,arrhythmia, etc.).This is directly related to the quality of the treatments. The results of the research showed that nurses should follow the cerebral oxygenation with non-invasive technique by constantly moving away from the invasive methods that cause many complications such as infection,arrhythmia,vascular injury to patients in the neurosurgery intensive care unit.

Since the oxygenation status of intensive care patients is measured and monitored with a pulse oximeter,the hypoxia state occurring in oxygenation in the brain tissue cannot be detected early. Standard methods used in the measurement of cerebral oxygenation have significant limitations in these patients.Jugular venous bulb oximetry measurement is an expensive method that requires invasive procedure;there is a risk of many complications such as infection on the patient, risk of tissue integrity deterioration,vascular injuries during bleeding of the catheter,bleeding; assessment of the measurement is essential by neurosurgeons;In addition, this method may miss regional ischemia.Non-invasive techniques such as transcranial doppler ultrasonography or electroencephalography(EEG) are other methods used indirectly to assess the adequacy of cerebral blood flow or the presence of ischemia.However,transcranial doppler and EEG are difficult to interpret by non-specialists. Cerebral oximetry device that measures oxygenation of the brain;It is important because it is a non-invasive method that monitors changes in cerebral oxygen metabolism,can provide continuous at the bedside, provides accurate and precise results as well as invasive methods,can provide nurses the convenience of interpretation independently in order not to cause secondary complications in nursing applications.Therefore,it can be easily evaluated in terms of nurses who are able to provide reliable and real-time data from several areas of the brain simultaneously, which is effective for the prevention and early detection of secondary injuries such as re-bleeding, vasospasm,cerebral ischemia,cerebral edema and seizure,and for 24 hours of patients.Cerebral oximetry device that works with near infrared spectroscopy(NIRS) technology,which can be used as a bedside monitor, is considered to be the most suitable device for patients and healthcare workers.