A Detailed Protocol for Physiological Parameters Acquisition and Analysis in Neurosurgical Critical Patients

Summary

Recently, we have developed a portable multimodality monitoring system for the monitoring of various physiological parameters in neurosurgical critical patients. Detailed protocols on how to use this multimodality monitoring system are presented here.

Abstract

Intracranial pressure (ICP) monitoring is now widely used in neurosurgical critical patients. Besides mean ICP value, the ICP derived parameters such as ICP waveform, amplitude of pulse (AMP), the correlation of ICP amplitude and ICP mean (RAP), pressure reactivity index (PRx), ICP and arterial blood pressure (ABP) wave amplitude correlation (IAAC), and so on, can reflect intracranial status, predict prognosis, and can also be used as guidance of proper treatment. However, most of the clinicians focus only on the mean ICP value while ignoring these parameters because of the limitations of the current devices. We have recently developed a multimodality monitoring system to address these drawbacks. This portable, user-friendly system will use a data collecting and storing device to continuously acquire patients' physiological parameters first, i.e., ABP, ICP, and oxygen saturation, and then analyze these physiological parameters. We hope that the multimodality monitoring system will be accepted as a key measure to monitor physiological parameters, to analyze the current clinical status, and to predict the prognosis of the neurosurgical critical patients.

Introduction

ICP monitoring is widely used to evaluate intracranial status in neurosurgery department, especially in neurosurgical critical patients^1,2,3. Besides mean ICP value, the ICP derived parameters such as ICP waveform, AMP, RAP, PRx, IAAC, and so on, can reflect the status of intracerebral circulation, cerebrospinal compensatory reserve, and brain compliance^{4,5,6,7,8,9,10,11,12,13}. They can be indicative of impending neurological deterioration and even outcome of patients^{14,15,16,17,18}. They can also be used as guidance of proper treatment¹⁹. However, most of the clinicians focus only on the mean ICP value while ignoring these parameters. This is partly because there are few specific devices that are suitable for clinicians in their daily clinical work.

To address these drawbacks, we have recently developed a multimodality monitoring system. We use an automatic data collecting and storing device to continuously acquire patients' physiological information such as blood pressure, ICP, and oxygen saturation, and analyze these physiological parameters in order to reveal the current clinical status and, hopefully, predict the prognosis of the neurosurgical critical patients. This multimodality monitoring system has several advantages: (1) it can collect real-time data at high frequency, (2) it can record multiple parameters, i.e., ICP waveform, PRx, RAP, and IAAC, (3) it can achieve long term continuous monitoring, and (4) it is portable and easy to learn.

The objective of this article, therefore, is to show a detailed method of how to use the multimodality monitoring system to record various physiological parameters in neurosurgical critical patients.

Protocol

This protocol was approved by the Institutional Review Board of Renji Hospital, Shanghai Jiaotong University School of Medicine.

1. Preparation of the Patient

NOTE: ICP sensor is placed in the patient by a surgical operation (Figure 1). The sensor is placed in the epidural space, subdural space, parenchyma, or ventricular system.

1. Connect the ICP monitoring machine with the bedside monitor via a specific communication cable.
2. Adjust the reference of patient's bedside monitor, so that the data from the bedside monitor are in accordance with the ICP monitoring machine.
3. Perform an arterial line placement on patient's left or right radial artery²⁰.
4. Connect the arterial line with the baroreceptor.
5. Connect the pressure transducer with patient's bedside monitor via a communication cable.
6. Zero adjust the bedside monitor so that the measured blood pressure coincides with the actual value.

2. Recording of Physiological Parameters

1. Connect the patient's bedside monitor with the data collecting and storing device via a network cable.
2. Press the power button to turn on the data collecting device.
3. Wait for a few seconds until the multimodality monitoring software runs automatically.
4. Enter the information of the patient, including the name, ID, diagnosis, and initial Glasgow Coma Scale (GCS).
5. Click the "Save and start monitoring" button to start data collecting and storing.
6. Click the "Turn off" button on the screen at the end of the data acquisition (Figure 2).
7. Enter the final GCS.

3. Parameter Analysis

1. Dump the stored data to a U-disk through universal serial bus (USB) interfaces on the host.
2. Enter a user name and password to log in to the analysis server.
3. Click the "Create new record" button and select the data file in the U-disk to start uploading.
4. Wait for around 10 to 20 min before the data are analyzed (depending on the data size).
5. Click the "Detail" button of each record to see the result.
6. Click the "Chart viewing" to see the final diagram.
7. Drag the timeline to see more detail.
8. Click the "scattergram" button to see the distribution of the parameters.

Results

This new multimodality monitoring system was applied on 22 neurosurgical critical patients (15 males). 12 of them (54.55%) had suffered from traumatic brain injury (TBI), 9 of them (40.91%) had intracranial hemorrhage and 1 of them (4.55%) had severe cerebral infarction. The total monitoring time is more than 1,900 h (about 88 h per patient). After successful surgery, we continuously monitored and analyzed their ICP, BP, CPP, PRx, RAP, and IAAC. Figure 3 show...

Discussion

This aim of this article is to introduce the new multimodality monitoring and analyzing system for neurosurgical critical patients, which can be used to monitor physiological parameters, analyze the current clinical status and, hopefully, predict the prognosis of the neurosurgical critical patients. Nowadays, the focus of ICP monitoring is mainly on the mean ICP value while ignoring other parameters, which may carry risks of inaccuracy or delay^4,5,

Materials

Name	Company	Catalog Number	Comments
Bedside monitor	Philips	IntelliVue MP40 M8003A	With interfacing module
ICP monitoring machine	Johnson & Johnson or Sophysa
Arterial cannula	BD	REF682245
Pressure transducer	Haisheng Medical	DBPT-0103
Data collection device	Shanghai Haoju	Neumatic
Computer			Requires Windows operating system