kanzya ha heiki da to iimasita.

は marks 患者 as the topic of the quoted statement.

So inside 患者は平気だ, the speaker is talking about the patient and saying something about that patient.

A useful way to think about it is:

• 患者は = as for the patient
• 平気だ = is fine / is okay

In Japanese, は often sets up what the sentence is about, rather than simply marking the grammatical subject the way English does.

と is the quotation particle here.

It marks the content of what was said:

• 患者は平気だ = the quoted statement
• と言いました = said

So the structure is:

• [quoted content] + と + 言いました

This is one of the most common patterns in Japanese for reporting speech or thoughts.

Examples:

• 行くと言いました = said that they would go
• 大丈夫だと言いました = said that it was okay

Because 平気 behaves like a na-adjective / noun-like predicate, and in plain style it needs だ when it stands at the end of a clause.

So:

• 平気だ = is okay / is fine

In this sentence, that whole clause is being quoted before と, so the plain form だ is used.

This is very important: with na-adjectives and nouns, you normally need だ before と in this kind of plain quoted statement.

Compare:

• 静かだと言いました = said it was quiet
• 学生だと言いました = said that he/she was a student

If you leave out だ here, it usually sounds ungrammatical.

Yes, but it means something slightly different in feel.

• 平気だと言いました reports the content in a neutral/plain way.
• 平気ですと言いました sounds more like quoting the exact polite wording that someone used.

So:

• 平気だと言いました = said that the patient was fine
• 平気ですと言いました = said The patient is fine in polite speech

The version with だ is very common when summarizing what someone said, not necessarily repeating their exact words.

Because Japanese usually puts the main verb at the end of the sentence.

Here, the action of the whole sentence is said, so 言いました comes last.

The quoted content comes before it:

• 患者は平気だ = what was said
• と言いました = said

This is a very standard Japanese word order pattern.

That is normal in Japanese. The subject of 言いました is omitted because it is understood from context.

So this sentence does not explicitly tell you who said it. Depending on context, it could mean:

• the doctor said it
• a nurse said it
• he said it
• she said it

Japanese often leaves out information that is already known or easy to infer.

Not exactly. 患者 is the topic of the quoted clause, not necessarily the subject of the entire sentence.

The sentence has two layers:

1. Quoted clause: 患者は平気だ
2. Main clause: と言いました

So 患者 belongs to the inner statement, while the outer verb 言いました has an omitted subject such as he/she/the doctor.

That is why this sentence can feel a little tricky at first: one noun appears, but the sentence is actually about two different things:

• what was said
• who said it

Yes, you could, but the nuance changes.

• 患者は平気だ focuses on the patient as the topic: as for the patient, he/she is fine
• 患者が平気だ puts more direct focus on the patient as the one who is fine

So:

• 患者は平気だと言いました = said that the patient was fine
• 患者が平気だと言いました = said that it was the patient who was fine / said the patient was fine, with more focus on patient

In many contexts, は is the more natural neutral choice if you are simply talking about the patient.

平気 is usually treated as a na-adjective (or a noun-like word that can act as a predicate with だ).

That is why you get forms like:

• 平気だ = is fine
• 平気です = is fine
• 平気な人 = a calm/unbothered person
• 平気で = calmly / without concern

In this sentence, 平気だ is the predicate of the quoted clause.

This is very common in Japanese.

The quoted content often appears in plain form, while the main sentence can still be polite.

So you can have:

• quoted clause: plain
• main verb: polite

Example pattern:

• Aだと思います
• Aだと言いました
• Aだと聞きました

This does not make the sentence rude. It is just the normal grammar of embedding a statement inside a larger sentence.

It is usually understood as an indirect quote or a content quote: reporting what was said.

So it is closer to:

• said that the patient was fine

rather than necessarily:

• said, The patient is fine

Japanese と can be used for both direct and indirect quotation, and context decides how exact the wording is supposed to be.

Because this sentence uses 平気だ in plain form, it often feels more like reporting the content than reproducing exact spoken words.

Yes.

By itself, 患者は平気だ is a complete plain-style sentence meaning that the patient is fine/okay.

In your full sentence, that complete sentence is being embedded before と and then followed by 言いました.

So you can think of the full sentence as:

• 患者は平気だ。
• Someone said that.

That is a helpful way to understand Japanese quotation structure.