Dr Hanna, who is interim head of the trust's Evelina London Children's Hospital, said up to half of all planned treatments could be cancelled as the trust redeployed its senior doctors - and this is on top of the impact of postponements during previous walkouts.
She said the cumulative impact of this was particularly problematic for children who are growing and developing.
NHS Providers, which represents health managers, said such concerns were widespread.
Chief executive Sir Julian Hartley said: "It's clear from our extensive dialogue with trust leaders that we are in uncharted territory.
"We need a solution to prevent further strikes and we need it now."
The organisation also released a series of statements provided by hospital chief executives.
Writing a nursing paper can be a challenging task, especially when balancing a full workload, clinical hours, and personal responsibilities. Crafting a well-researched, comprehensive, and properly formatted paper requires significant time, focus, and expertise in the field of nursing. Many students find themselves overwhelmed with the depth of research needed and the specific guidelines that must be followed.
If you're struggling to meet deadlines or need professional assistance, a nursing paper writing service can offer the support you need. These services connect you with expert writers who specialize in nursing and healthcare topics, ensuring your paper is accurate, informative, and meets academic standards. With such a service, you can receive custom-written papers, personalized to your requirements, and backed by research that enhances the quality of your work.