腰椎穿刺の検査後「頭痛予防のため検査後は水分を取って横になる」は間違いか?

久しぶりに麻酔科領域に関する記事です。麻酔科で行う神経ブロックや脊髄くも膜下麻酔、髄液検査である腰椎穿刺などの後、頭痛を起こす場合があります。脊髄くも膜下麻酔では非常に針が細いので、頭痛の頻度は非常に低いのですが、それ以外は針が太くかなりの頻度で穿刺後の頭痛を起こします。その頭痛の予防のため「十分な水分補給と、安静」を指示する場合が多く、手術時の麻酔の場合はもちろんしばらく横になっていることになります。

しかし、コクランのデータベースのシステマティックレビューでは、「水分補給」はしてもしなくても変わらないこと、「安静」に関しては腰椎穿刺の直後から動く場合に比べて、腰椎穿刺の後、横になって安静にしている方が穿刺後頭痛の発生が多くなっていました。

これまで、いろいろな昔から行われてきた医療行為や治療が否定されていますが、いまだに当たり前のように行われています。今回の頭痛予防に関しても医学的根拠がなく行われてきたのでしょう。何となく頭痛予防には「安静」が良さそうですし、髄液が漏れてきてしまうのでそれを「水分補給」で補うという考えになったのでしょう。単なるイメージで行われてきた習慣だったのかもしれません。

最近「WELQ」などが医学的根拠のない記事を掲載して問題になっていますが、そもそもの医療行為の中にも医学的根拠がないものもいっぱい存在しています。

エビデンスはデータを意図的に十分操作可能ですし、最初に結論があって、その結論と異なった研究はそもそも発表されない傾向が強いですし、研究費がどこから出ているかでスポンサー有利の結果が出てしまいます。

根拠、根拠と言っていますが、不確かなことなので研究でエビデンスを出し、あたかも正しいことのように見せる必要があるのですが、実際は明確な根拠とはなり得ません。本当に確かなことであれば、どの研究も同じ結果になるはずです。「心臓の動きが止まり、呼吸も止まれば、人は死ぬ」ということは誰が確かめても同じ答えです。「いやいや、私の研究では心肺停止状態で5年以上生きている人が80%います。」なんてこと言う人はいません。そもそも、エビデンスが必要だと言われることは全て不確かなことであり不明瞭であり、絶対正しいなどとは言えないのです。また、エビデンスを出すとき、個々のデータは重要視されず、統計的な処理された、有意差があるかどうかが問題になるだけです。つまりデータは平均化され、個々の個人差などは無視されてしまいます。

そうなると、通常の治療で改善しない患者さんは見放されてしまいます。ひどい場合にはそのような患者さんを精神科疾患にしてしまいます。

もう一度ヒポクラテスの時代に戻って、医療の原点に帰ることが必要なのかもしれません。

Posture and fluids for preventing post-dural puncture headache.

Cochrane Database Syst Rev. 2016 Mar 7

Abstract
BACKGROUND:
Post-dural puncture headache (PDPH) is a common complication of lumbar punctures. Several theories have identified the leakage of cerebrospinal fluid (CSF) through the hole in the dura as a cause of this side effect. It is therefore necessary to take preventive measures to avoid this complication. Prolonged bed rest has been used to treat PDPH once it has started, but it is unknown whether prolonged bed rest can also be used to prevent it. Similarly, the value of administering fluids additional to those of normal dietary intake to restore the loss of CSF produced by the puncture is unknown. This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (Issue 7, 2013) on “Posture and fluids for preventing post-dural puncture headache”.
OBJECTIVES:
To assess whether prolonged bed rest combined with different body and head positions, as well as administration of supplementary fluids after lumbar puncture, prevent the onset of PDPH in people undergoing lumbar puncture for diagnostic or therapeutic purposes.
SEARCH METHODS:
We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and LILACS, as well as trial registries up to February 2015.
SELECTION CRITERIA:
We identified randomized controlled trials that compared the effects of bed rest versus immediate mobilization, head-down tilt versus horizontal position, prone versus supine positions during bed rest, and administration of supplementary fluids versus no/less supplementation, as prevention measures for PDPH in people who have undergone lumbar puncture.
DATA COLLECTION AND ANALYSIS:
Two review authors independently assessed the studies for eligibility through the web-based software EROS (Early Review Organizing Software). Two different review authors independently assessed risk of bias using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. We resolved any disagreements by consensus. We extracted data on cases of PDPH, severe PDPH, and any headache after lumbar puncture and performed intention-to-treat analyses and sensitivity analyses by risk of bias. We assessed the evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and created a ‘Summary of findings’ table.
MAIN RESULTS:
We included 24 trials with 2996 participants in this updated review. The number of participants in each trial varied from 39 to 382. Most of the included studies compared bed rest versus immediate mobilization, and only two assessed the effects of supplementary fluids versus no supplementation. We judged the overall risk of bias of the included studies as low to unclear. The overall quality of evidence was low to moderate, downgraded because of the risk of bias assessment in most cases. The primary outcome in our review was the presence of PDPH.There was low quality evidence for an absence of benefits associated with bed rest compared with immediate mobilization on the incidence of severe PDPH (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.68 to 1.41; participants = 1568; studies = 9) and moderate quality evidence on the incidence of any headache after lumbar puncture (RR 1.16; 95% CI 1.02 to 1.32; participants = 2477; studies = 18). Furthermore, bed rest probably increased PDPH (RR 1.24; 95% CI 1.04 to 1.48; participants = 1519; studies = 12) compared with immediate mobilization. An analysis restricted to the most methodologically rigorous trials (i.e. those with low risk of bias in allocation method, missing data and blinding of outcome assessment) gave similar results. There was low quality evidence for an absence of benefits associated with fluid supplementation on the incidence of severe PDPH (RR 0.67; 95% CI 0.26 to 1.73; participants = 100; studies = 1) and PDPH (RR 1; 95% CI 0.59 to 1.69; participants = 100; studies = 1), and moderate quality evidence on the incidence of any headache after lumbar puncture (RR 0.94; 95% CI 0.66 to 1.34; participants = 200; studies = 2). We did not expect other adverse events and did not assess them in this review.
AUTHORS’ CONCLUSIONS:
Since the previous version of this review, we found one new study for inclusion, but the conclusion remains unchanged. We considered the quality of the evidence for most of the outcomes assessed in this review to be low to moderate. As identified studies had shortcomings on aspects related to randomization and blinding of outcome assessment, we therefore downgraded the quality of the evidence. In general, there was no evidence suggesting that routine bed rest after dural puncture is beneficial for the prevention of PDPH onset. The role of fluid supplementation in the prevention of PDPH remains unclear.

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