kidou wo kakuninsuru.

It is read:

きどう を かくにんする

• 気道（きどう） = airway
• を = object marker
• 確認する（かくにんする） = to check, confirm, verify

So the full sentence is きどうをかくにんする.

気道 means airway.

In medical Japanese, it refers to the passage through which air moves during breathing. In first-aid or emergency contexts, checking the 気道 means making sure the person’s airway is open and not blocked.

を marks the direct object of the verb.

In this sentence:

• 気道 = the thing being checked
• 確認する = to check/confirm

So 気道を確認する literally means to check the airway.

A very literal breakdown is:

• 気道 = airway
• を = object marker
• 確認する = check/confirm

確認する means to confirm, to verify, or to check carefully.

It is more formal and deliberate than 見る, which simply means to see or to look.

Compare:

• 気道を見る = look at the airway
• 気道を確認する = check/confirm the airway

In a medical or procedural context, 確認する is much more natural because it implies making sure something is in the proper condition.

Yes. 確認する is the plain/dictionary form.

This form is commonly used in:

• manuals
• instructions
• procedural steps
• note-taking
• headings
• neutral descriptions of actions

So 気道を確認する。 sounds like an instruction step such as Check the airway.

If you wanted to make it polite, you could say:

• 気道を確認します。

Japanese often omits the subject when it is obvious from context.

So 気道を確認する。 does not explicitly say who is checking the airway. Depending on context, it could mean:

• Check the airway.
• I check the airway.
• We check the airway.
• The responder checks the airway.

In instructional or medical contexts, the omitted subject is often understood as the person performing the procedure.

Not directly in grammar, but it can function like an instruction.

Grammatically, 確認する is just the plain dictionary form, not the direct command form. However, in manuals and step-by-step instructions, the dictionary form often works like an instruction:

• 気道を確認する。 = Check the airway.

A stronger direct command would be:

• 気道を確認しろ。
• 気道を確認してください。 (polite request)

So the original sentence is best understood as a neutral procedural instruction, not a harsh command.

Normally, Japanese is written without spaces.

So the usual writing would be:

気道を確認する。

Spaces are often added only for learners, textbooks, or clarity. They help beginners see the parts of the sentence more easily, but they are not standard in ordinary Japanese writing.

Yes.

確認 is a noun meaning confirmation/check, and when combined with する, it becomes a verb:

• 確認 = confirmation
• 確認する = to confirm / to check

This is very common in Japanese. Other examples:

• 勉強する = to study
• 説明する = to explain
• 連絡する = to contact

So 確認する is a very typical suru-verb.

This phrase is especially common in:

• first aid
• emergency response
• CPR instructions
• medical training
• hospital or nursing procedures

For example, when following an emergency checklist, one step might be:

• 気道を確認する。
• 呼吸を確認する。
• 脈を確認する。

So it sounds like a step in a professional or instructional sequence.

Yes, in many real-life situations it would.

Compare:

• 気道を確認する。
  Neutral, manual-like, instructional, checklist style

• 気道を確認してください。
  Polite request: Please check the airway.

• 気道を確認します。
  Polite statement: I will check the airway / We check the airway

So the original sentence is natural if it is being used as a procedure step or written instruction. In direct spoken conversation, a polite form is often more natural.

Yes. The exact English translation depends on context.

In many situations, 確認する can mean:

• check
• confirm
• verify
• make sure

In this sentence, check the airway is the most natural English translation. But the Japanese nuance includes the idea of making sure the airway is in the proper state. So it is a little more careful and purposeful than simply look at the airway.