## 6 Open Issues and Research Challenges  
This section discusses the open issues and research challenges associated with the smart healthcare systems which eventually have a detrimental effect on the patients' health during the remote monitoring of their health status. * There is a lack of security standardization in smart healthcare--current health safety standards are too conventional and have become obsolete. Neither are they robust enough to sustain modern security attacks. The need for standardization, particularly in health care, can minimize the risk of mistakes, increase patient safety, and make a real difference to the patients experience. Moreover, arising security issues arising from the remote monitoring of patients can have a deleterious impact on their health, and can discourage them from taking medication from that particular healthcare provider. Thus, it can affect the reputation of the hospital's management which can reduce their overall revenue [110];
* Inefficient first line of defence--The spectrum of security risks and newly discovered security vulnerabilities for intelligent health systems keeps expanding. Security threats have less of an impact on smart healthcare environments when a variety of defences, including firewalls and intrusion detection systems, are used effectively and efficiently. However, despite the fact that they offer a number of advantages that can safeguard health systems, they are ineffective at spotting contemporary security threats; hence they continue to be open to assault [111];
* Non-availability of physical layer access control--The basis of all security measures is the physical security layer. The access control restrictions imposed by the existing security measures apply only to the application layer. Because the wireless communication in the physical layer is unprotected, the new security threats target it. The loss of physical security typically leaves the smart healthcare system completely exposed. Further, an adversary can easily modify the data extracted from implantable medical  
Figure 9: Evaluation of the scalability comparison of the blockchain network. devices such as pacemaker, artificial joints, cardiac implants., attached to the patient's body, which gives rise to security issues in wireless communication between patient and healthcare professionals during the remote treatment [112];
* Modern security attacks on smart healthcare systems--In addition to the typical attacks such as DDoS, MITM, ransomware., the attackers have discovered new methods of system attacking a system. The latest attacks include: software supply chain attacks; attackers take advantage of the supplier network of a healthcare institution and capitalize on the system's vulnerability. Internet of Things (IoT) attacks, A wide variety of endpoint devices is now remotely connected to the Internet. The malware interprets the changes caused by the system and manipulates the signals it receives to carry out destructive activities [113];
* Accessibility of advanced technology in smart healthcare--With the modernization of smart healthcare systems, healthcare professionals and staff have to manage advanced technologies to handle the medical equipment for the remote monitoring of patients. However, not all the healthcare professionals have had sufficient experience and training enabling them to tackle the patient's health symptoms through the usage of innovative technologies. Thus, hospital management should train their professionals or staff so that they become familiar with these technologies, although this can be costly for hospitals [111; 114];
* Scalability: Scalability is one of the major concerns that needs to be managed during the wireless communication between patient and doctor in the remote treatment set up. Depending on the patient's health symptoms, healthcare professionals may require several items of medical equipment and various implantable sensors to gather the health data of patients and determine further treatment.