犬・猫の呼吸器臨床研究会

短頭種気道症候群(BAS)研究班の報告(2019.1.7更新 計45)

短頭種気道症候群一般、非短頭種の咽頭閉塞、重度上気道閉塞疾患に対する気管切開、犬の睡眠時無呼吸症候群の文献レビュー

テーマは、「BASの術前評価に応じた術式選択」「咽頭気道閉塞症候群89例」「気管切開下軟口蓋拡大切除術の外科成績」、「睡眠時無呼吸症候群の定義と定量」、「一時的気管切開200例-適応、周術期安全性、救命率の向上」、「永久気管切開術70例-適応、新術式による術後合併症の減少と長期QOLの安定」、「Tチューブによる重度喉頭気管閉塞疾患の管理」

短頭種気道症候群 BAS、一般


Hendricks JC. Brachycephalic Airway Syndrome In: King LG, ed. Textbook of Respiratory Diseases in Dogs and Cats. Philadelphia: Elsevier SAUNDERS, 2004;310-318.

コメント:良著。とくに咽頭気道の代償不全に関して詳細に記述しています。BASを語るのなら本書を少なくとも3回は熟読していただきたいと思います(犬・猫の呼吸器科 城下-2018.11.28)。


Hoareau GL, Jourdan G, Mellema M, et al. Evaluation of arterial blood gases and arterial blood pressures in brachycephalic dogs. J Vet Intern Med 2012;26:897-904.

短頭犬種の動脈血ガスと血圧の評価

BACKGROUND: Brachycephalic dogs (BD) are prone to congenital upper airway obstruction (brachycephalic syndrome, BS). In humans suffering from sleep apnea, upper airway obstruction is known to cause hypertension. There is no information regarding the influence of BS in dogs on cardiorespiratory physiology.

HYPOTHESIS: BD are prone to lower P(a) O(2), higher P(a) CO (2), and hypertension compared with meso- or dolicocephalic dogs (MDD). ANIMALS: Eleven BD and 11 MDD.

METHODS: After a questionnaire was completed by the owner, a physical examination was performed. Height and thoracic circumferences were measured. Arterial blood gases, electrolyte concentrations, and packed cell volume (PCV) were measured. Systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressure recordings were performed.

RESULTS: A total of 7 French and 4 English bulldogs met the inclusion criteria. The control group consisted in 6 Beagles, 2 mixed breed dogs, 1 Staffordshire Bull Terrier, 1 Parson Russell Terrier, and 1 Australian Cattle Dog. Statistically, BD had lower P(a) O(2), higher P(a) CO2, and higher PCV when compared with controls (86.2 +/- 15.9 versus 100.2 +/- 12.6 mmHg, P = .017; 36.3 +/- 4.6 versus 32.7 +/- 2.6 mmHg, P = .019; 48.2 +/- 3.5 versus 44.2 +/- 5.4%, P = .026, respectively). Also, they had significantly higher SAP (177.6 +/- 25.0 versus 153.5 +/- 21.7 mmHg, P = .013), MAP (123.3 +/- 17.1 versus 108.3 +/- 12.2 mmHg, P = .014), and DAP (95.3 +/- 19.2 versus 83.0 +/- 11.5 mmHg, P = .042). BD with a P(a) CO (2) >35 mmHg were significantly older than those with a P(a) CO (2) </=35 mmHg (58 +/- 16 and 30 +/- 11 months, P = .004).

CONCLUSION: Results of this study suggest that some BD are prone to lower P(a) O(2), higher P(a) CO (2), and hypertension when compared with MDD. Age may be a contributing factor.

コメント:短頭種では、非短頭種に比べ低O2血症、高CO2血症、高血圧が認められることを示し、それらの機序を考察した文献(まるふく動物病院 福田大介-2019.1.5)。


Johnson LR, Mayhew PD, Steffey MA, et al. Upper airway obstruction in Norwich Terriers: 16 cases. J Vet Intern Med 2013;27:1409-1415.

ノーリッチテリアにおける上気道閉塞:16症例

BACKGROUND: Norwich Terriers have grown increasingly popular as show animals and pets, and awareness of respiratory problems within the breed is growing. OBJECTIVE: To describe components of obstructive upper airway syndrome in a nonbrachycephalic terrier breed. ANIMALS: Sixteen Norwich Terriers; 12 with and 4 without clinical signs of respiratory disease. METHODS: Prospective case series. Physical and laryngoscopic examinations were performed by 1 investigator in all dogs. Medical and surgical interventions were summarized and results of follow-up examination or owner reports were recorded. RESULTS: The study population was comprised of 9 females (6 intact) and 7 males (5 intact). Median age was 3.0 years (range, 0.5-11 years). Of 12 dogs presented for a respiratory complaint, physical examination was normal in 4 dogs. Laryngoscopic examination was abnormal in 11/12 dogs with redundant supra-arytenoid folds, laryngeal collapse, everted laryngeal saccules, and a narrowed laryngeal opening in most. Of 4 dogs lacking clinical signs, all had normal physical examination; however, 3/4 dogs had similar appearance of the larynx to dogs with clinical signs. Response to surgical intervention was minimal to moderate in all dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Norwich Terriers suffer from an upper airway obstructive syndrome that differs from that encountered in brachycephalic breeds. Affected dogs are difficult to identify without laryngoscopic examination because of the lack of clinical signs and abnormalities in physical examination findings, despite severe airway obstruction. Care is warranted when anesthetizing Norwich Terriers because of the small size of the laryngeal opening.

コメント:ノーリッチテリアは、短頭犬種とは異なる上気道閉塞症候群(余剰な披裂軟骨上ヒダ、喉頭虚脱、反転喉頭小嚢、狭窄した喉頭開口部)に罹患していることがあり、重度の狭窄にもかかわらず臨床徴候や身体検査に異常がないことがある(いいのペットクリニック 飯野 亮太-181228)。


Packer RM, Hendricks A, Tivers MS, Burn CC. Impact of Facial Conformation on Canine Health: Brachycephalic Obstructive Airway Syndrome. PLoS One. 2015 Oct 28;10(10):e0137496.(Free full text)

短頭種気道閉塞症候群(BOAS)-頭蓋構造が犬の健康に与える影響

The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly–foreshortening of the facial skeleton–is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring.

コメント:解剖学的な構造によって特徴づけられるBASは定量的な診断指標がない。今回、回顧的な検討により、マズル長が短縮する程にBAS発症のリスクが増加すること、BASは頭蓋長の半分以下のマズル長の犬のみで発症すること、頚囲の増大や肥満がBASの発症リスクを増加させることを発見した(ダクタリ動物病院 東京医療センター 田畑達彦-2018.11.29)。


Haimel G, Dupre G. Brachycephalic airway syndrome: a comparative study between pugs and French bulldogs. J Small Anim Pract 2015;56:714-719.

短頭種気道症候群:パグとフレンチブルの比較研究

OBJECTIVE: To compare clinical features of brachycephalic airway syndrome and long-term surgical outcomes between pugs and French bulldogs and evaluate the influence of laryngeal collapse.

METHODS: This retrospective study included 72 dogs that underwent wedge rhinoplasty and folded flap palatoplasty for brachycephalic airway syndrome. Epidemiological data, clinical signs, postoperative complications and owners’ responses to a questionnaire at least six months after surgery were compared between pugs and French bulldogs. Spearman’s rank correlation tests were used for associating laryngeal collapse with age and respiratory signs before and after surgery.

RESULTS: On the basis of the results of the owners’ questionnaires (available in 52/72 dogs), French bulldogs presented with lower activity levels and more severe digestive signs than pugs. Owners perceived clinical improvement in 88 . 5% of all dogs. The grades of respiratory and digestive signs were not different between the breeds in the long-term follow-up, and the grade of laryngeal collapse did not influence the grade of respiratory signs or surgical outcome.

CLINICAL SIGNIFICANCE: Surgical treatment resulted in improved clinical signs in pugs and French bulldogs with brachycephalic airway syndrome, with a high owner satisfaction rate. There were no correlations between the severity of laryngeal collapse and overall respiratory signs or prognosis.

コメント:外鼻孔狭窄・軟口蓋過長整復術を行ったフレンチ・ブルドッグとパグ72頭について比較した後ろ向き研究。両犬種とも術後経過はおおむね良好で、オーナーの満足度も高かった。喉頭虚脱の重症度は、臨床症状や予後と相関が認められなかった(まるふく動物病院 福田大介-2018.12.20)。


Liu NC, Troconis EL, Kalmar L, et al. Conformational risk factors of brachycephalic obstructive airway syndrome (BOAS) in pugs, French bulldogs, and bulldogs. PLoS One 2017;12:e0181928.

パグ、フレンチブル、ブルドッグのBASの構造的危険因子

Extremely brachycephalic, or short-muzzled, dog breeds such as pugs, French bulldogs, and bulldogs are prone to the conformation-related respiratory disorder-brachycephalic obstructive airway syndrome (BOAS). Affected dogs present with a wide range of clinical signs from snoring and exercise intolerance, to life-threatening events such as syncope. In this study, conformational risk factors for BOAS that could potentially aid in breeding away from BOAS were sought. Six hundred and four pugs, French bulldogs, and bulldogs were included in the study. Soft tape measurements of the head and body were used and the inter-observer reproducibility was evaluated. Breed-specific models were developed to assess the associations between the conformational factors and BOAS status based on functional grading. The models were further validated by means of a BOAS index, which is an objective measurement of respiratory function using whole-body barometric plethysmography. The final models have good predictive power for discriminating BOAS (-) and BOAS (+) phenotypes indicated by the area under the curve values of >80% on the receiver operating curves. When other factors were controlled, stenotic nostrils were associated with BOAS in all three breeds; pugs and bulldogs with higher body condition scores (BCS) had a higher risk of developing BOAS. Among the standardized conformational measurements (i.e. craniofacial ratio (CFR), eye width ratio (EWR), skull index (SI), neck girth ratio (NGR), and neck length ratio (NLR)), for pugs EWR and SI, for French bulldogs NGR and NLR, and for bulldogs SI and NGR showed significant associations with BOAS status. However, the NGR in bulldogs was the only significant predictor that also had satisfactory inter-observer reproducibility. A NGR higher than 0.71 in male bulldogs was predictive of BOAS with approximately 70% sensitivity and specificity. In conclusion, stenotic nostrils, BCS, and NGR were found to be valid, easily applicable predictors for BOAS (+).

コメント:604頭のパグ、フレンチブル、ブルドッグで、BASの構造的危険因子を調べた報告。3犬種すべてに共通する危険因子:外鼻孔狭窄の重症度。パグ、ブルドッグに共通する危険因子:BCS。NGR(胸郭に対する首の太さ)は、測定者間の誤差が少なく、オスのブルドッグで信頼できる危険因子である。ただし、これら構造的評価だけでなく、機能的評価を組み合わせることがとても重要である(まるふく動物病院 福田大介-2018.12.20)


Rutherford L, Beever L, Bruce M, et al. Assessment of computed tomography derived cricoid cartilage and tracheal dimensions to evaluate degree of cricoid narrowing in brachycephalic dogs. Vet Radiol Ultrasound 2017;58:634-646.  doi:10.1111/vru.12526

短頭犬種の輪状軟骨狭窄評価のための輪状軟骨と気管横断面のCT評価

The aims of this observational, analytical, retrospective study were to (i) obtain computed tomographic (CT) cricoid dimensions (height, width, and transverse-sectional area), (ii) compare the cricoid dimensions between brachycephalic and mesaticephalic breeds, and (iii) compare cricoid cartilage dimensions between dogs without and affected with brachycephalic airway syndrome. The study is important to help to further evaluate and understand the anatomical components of brachycephalic airway syndrome. Measurements were performed in 147 brachycephalic and 59 mesaticephalic dogs. The cricoid cartilage was found to be significantly more oval in Pugs and French Bulldogs compared to mesaticephalic breeds. The cricoid cartilage transverse-sectional area was smallest for the Pug and, after adjusting for weight, significantly smaller for Pugs (P < 0.001), Boston Terriers (P = 0.001), and French Bulldogs (P < 0.001) compared to Jack Russell Terriers. The tracheal transverse-sectional area at C4 of English Bulldogs was significantly smaller than for Jack Russell Terriers (P = 0.005) and Labradors (P < 0.001). The cricoid cartilage transverse-sectional area:weight ratio was significantly lower in brachycephalic breeds compared to mesaticephalic breeds (P < 0.001). The cricoid cartilage:trachea at C4 transverse-sectional area for brachycephalic dogs was significantly larger than for mesaticephalic dogs (<0.001), demonstrating that the trachea was the narrowest part of the airway. No significant differences were found for cricoid dimensions between dogs affected with and without brachycephalic airway syndrome. However, large individual variation was found among the brachycephalic breeds and further studies investigating the relationship between cricoid cartilage size, laryngeal collapse, concurrent tracheal hypoplasia, and/or severity of brachycephalic airway syndrome are warranted.

コメント:CTを用いて体重で標準化した輪状軟骨の横断径などを犬種別で比較した論文。パグ、フレンチブルドッグが特に喉頭の狭い犬種として挙げられている(ダクタリ動物病院 東京医療センター 田畑達彦-2018.12.30


Ellis J, Leece EA. Nebulized Adrenaline in the Postoperative Management of Brachycephalic Obstructive Airway Syndrome in a Pug. J Am Anim Hosp Assoc 2017;53:107-110. doi: 10.5326/JAAHA-MS-6466

短頭種気道症候群の術後管理にアドレナリンを配合したネブライザー療法が有効であった1例

Brachycephalic obstructive airway syndrome is a common problem in certain breeds, and may necessitate surgical procedures, such as rhinoplasty, palatoplasty, laryngeal sacculectomy, and/or arytenoid laryngoplasty, to improve the quality of life. However, laryngeal edema may necessitate the use of temporary tracheostomy tubes postoperatively to maintain a patent airway. This case demonstrates that administration of nebulized adrenaline in the immediate postoperative period where upper airway obstruction is life threatening can be used to reduce edema, therefore avoiding the need for tracheostomy.

コメント:パグにおいて短頭種気道症候群ope後の喉頭浮腫に対し、一時気管切開でなくアドレナリン噴霧の有用性を検討した論文(ダクタリ動物病院 東京医療センター 田畑達彦-2018.11.29)。


Shaver SL, Barbur LA, Jimenez DA, et al. Evaluation of Gastroesophageal Reflux in Anesthetized Dogs with Brachycephalic Syndrome. J Am Anim Hosp Assoc 2017;53:24-31.

BAS犬の麻酔下胃食道逆流の評価

Brachycephalic airway syndrome may predispose to gastroesophageal reflux (GER) because of the high negative intrathoracic pressures required to overcome conformational partial upper airway obstruction. To investigate this, 20 dogs presenting for elective correction of brachycephalic airway syndrome (cases) and 20 non-brachycephalic dogs (controls) undergoing other elective surgeries were prospectively enrolled. Dogs underwent a standardized anesthetic protocol, and esophageal pH was monitored. Signalment, body weight, historical gastrointestinal and respiratory disease, complete blood count, serum biochemical values, radiographic findings, and anesthetic and surgical time were compared between cases and controls, and dogs that did and did not have basic (pH > 7.5), acidic (pH < 4), or any GER. Controls had higher mean esophageal pH (6.3) compared to cases (5.6, P = .019), but there was no difference in % with GER (cases 60%, controls 40%, P = .34). When all dogs were evaluated, dogs with GER had increased creatinine (P = .01), % positive for esophageal fluid on radiographs (P = .05), and body weight (P = .04) compared to those without GER. GER was common in both cases and controls, and cases had lower esophageal pH; however, greater numbers are required to determine if a true difference exists in % GER.

コメント:全身麻酔時、短頭種ではGER(胃食道逆流)が発生しやすいのかを調べるため、前向き研究を実施(短頭種20頭と非短頭種20頭で比較)した。結果として、短頭種群では麻酔中の食道内pHは非短頭種群に比べ低かったが、GERの発生率に有意差を認められなかった(まるふく動物病院 福田大介-2019.1.5)


Downing F, Gibson S. Anaesthesia of brachycephalic dogs. J Small Anim Pract 2018;59:725-733.

短頭種の麻酔

Brachycephalic breeds of dog have grown in popularity in the UK and so form an increasing proportion of cases requiring anaesthesia. These breeds are predisposed to several conditions, notably brachycephalic obstructive airway syndrome and gastro-oesophageal reflux, that have important implications for anaesthetic management and carry high risk for complications. This review incorporates peer-reviewed veterinary literature with clinical experience in a discussion on perioperative management of brachycephalic dogs. We focus on preoperative identification of common concurrent conditions, practical strategies for reducing anaesthetic risk and improving postoperative management. Comparisons of brachycephalic obstructive airway syndrome with the human condition of obstructive sleep apnoea are included where appropriate.

コメント:BASのレビュー。BASとヒトのOSAを比較している。OSA患者では、術前術後のCPAP療法や呼吸理学療法が必須となっているが、獣医療では、メリット・デメリットなどを考慮し適応を検討する必要がある(まるふく動物病院 福田大介-2018.12.20)。


 

フレンチ・ブルドッグ

Sabino CV, Holowaychuk M, Bateman S. Management of acute respiratory distress syndrome in a French Bulldog using airway pressure release ventilation.J Vet Emerg Crit Care(San Antonio). 2013 Jul-Aug;23(4):447-54.

フレンチブルドッグに生じた  ARDSに対し気道圧開放換気(APRV)で管理した1例

OBJECTIVE: To describe the successful clinical management of a dog with acute respiratory distress syndrome (ARDS) using airway pressure release ventilation (APRV).

CASE SUMMARY: An 18-month-old female French Bulldog was presented for routine ovariohysterectomy and correction of brachycephalic airway obstruction syndrome. Following the surgical procedures, the dog developed aspiration pneumonia and ARDS. Her clinical condition failed to improve with conventional pressure-support mechanical ventilation and she was subsequently managed with APRV. She recovered fully and exhibited no clinical or radiographic abnormalities during follow-up examinations.

NEW OR UNIQUE INFORMATION PROVIDED: This is the first reported use of APRV to manage refractory hypoxemia associated with ARDS in a dog. This alternative mode of mechanical ventilation can be considered a feasible alternative in canine patients with ARDS.

コメント:18か月雌FBの不妊およびBAS整復手術後に生じた吸引性肺炎に続発するARDSの管理において気道圧開放換気(APRV)が奏功した症例報告(ダクタリ動物病院 東京医療センター 田畑達彦-2018.11.29)


Packer RM, Tivers MS. Strategies for the management and prevention of conformation-related respiratory disorders in brachycephalic dogs. Vet Med(Auckl). 2015 Jun 4;6:219-232. (Free full text)

短頭犬種における構造異常関連呼吸器障害の管理や予防法について

Brachycephalic (short-muzzled) dogs are increasingly popular pets worldwide, with marked increases in registrations of breeds such as the Pug and French Bulldog over the past decade in the UK. Despite their popularity, many brachycephalic breeds are affected by an early-onset, lifelong respiratory disorder, brachycephalic obstructive airway syndrome (BOAS). This disorder arises due to a mismatch in the proportions of the skull and the soft tissues held within the nose and pharynx, resulting in obstruction of the airway during respiration. Increased airway resistance encourages secondary changes such as eversion of the laryngeal saccules and collapse of the larynx. Clinical signs of BOAS are often early onset and chronic, including dyspnea, exercise intolerance, heat intolerance, and abnormal and increased respiratory noise. Episodes of severe dyspnea can also occur, leading to cyanosis, syncope, and death. BOAS may have a severe impact upon the welfare of affected dogs, compromising their ability to exercise, play, eat, and sleep. Although a well-described condition, with surgical treatments for the palliation of this disorder published since the 1920s, many dogs still experience airway restrictions postsurgically and a compromised quality of life. In addition, the prevalence of this disorder does not appear to have substantially reduced in this time, and may have increased. Ultimately, strategies to improve the breeding of these dogs to prevent BOAS are required to improve brachycephalic health and welfare. Recent studies have revealed conformational risk factors associated with BOAS, such as short muzzles and thick necks, which should be discouraged to avoid perpetuating this serious disorder. Positive changes to brachycephalic health may be impeded by a perception of BOAS being “normal for the breed”. This perception must be avoided by owners, breeders, and vets alike to prevent undertreatment of individuals and the perpetuation of this serious disorder to future generations of dogs.

コメント:短頭種の飼養頭数は増加しており、これらの犬種で認められる頭蓋骨と軟部組織比率のミスマッチによって生じるBASは、気道抵抗を上昇させることで喉頭小嚢の反転や喉頭虚脱、ひいてはチアノーゼや失神、死を引き起こしうる。BASに対する外科的治療は1920年代頃より文献が認められるが、いまだに術後の気流制限や不完全なQOLを経験している短頭種は多い。さらに、その罹患率は減るどころか、おそらく増加している。’その犬種では普通の構造である’という感覚が短頭種のQOLや健康を制限している(ダクタリ動物病院 東京医療センター 田畑達彦-2018.11.29)。


Reeve EJ, Sutton D, Friend EJ, Warren-Smith CMR. Documenting the prevalence of hiatal hernia and oesophageal abnormalities in brachycephalic dogs using fluoroscopy. J Small Anim Pract. 2017 Dec;58(12):703-708.

透視検査を用いた短頭種犬種における食道裂孔ヘルニアと食道異常の有病率の調査について

OBJECTIVES: To report the prevalence of abnormal fluoroscopic findings in brachycephalic dogs that were presented to a referral hospital for obstructive airway syndrome.

METHODS: Hospital records between May 2013 and November 2015 identified 36 brachycephalic dogs investigated for obstructive airway disease: 21 French bulldogs, six bulldogs, four Boston terriers, two pugs, two boxers and one shih-tzu. The presence or absence of hiatal hernia, delayed oesophageal transit, gastro-oesophageal reflux and redundant oesophagus were recorded.

RESULTS: Of the 36 dogs, 16 had hiatal hernia, all of which were French bulldogs; 31 dogs had delayed oesophageal transit time, 27 had gastro-oesophageal reflux, and four had redundant oesophagus.

CLINICAL SIGNIFICANCE: Clinical Significance: The prevalence of hiatal hernia is higher than expected in the French bulldog, and there was a high prevalence of oesophageal disease in this group in general. These results suggest a need to investigate similar cases for evidence of gastrointestinal disease that may also require attention.

コメント:単一施設において閉塞性気道疾患と診断された36頭の短頭種を用いた回顧的検討であり、食道裂孔ヘルニア、食道通過時間の遅延、胃食道逆流および食道過長の合併率を調査した。全体的に食道疾患の合併率は高く、特にFBは全例において食道裂孔ヘルニアを合併していた(ダクタリ動物病院 東京医療センター 田畑達彦-2018.11.29)。


 

犬の咽頭閉塞の病態


城下幸仁. 【子どものいびき・睡眠時無呼吸症候群を探求する】 犬の短頭種気道症候群の病態から学ぶもの. 小児歯科臨床 2016;21:25-32.

コメント:分野の違う歯科医や小児科医にも分かりやすいように記述しました(犬・猫の呼吸器科 城下-2018.11.28)。


Rubin JA, Holt DE, Reetz JA, et al. Signalment, clinical presentation, concurrent diseases, and diagnostic findings in 28 dogs with dynamic pharyngeal collapse (2008-2013). J Vet Intern Med 2015;29:815-821.

動的咽頭虚脱をもつ犬28頭のシグナルメント、臨床症状、併発疾患、および診断所見

BACKGROUND: Most information about pharyngeal collapse in dogs is anecdotal and extrapolated from human medicine. A single case report describing dynamic pharyngeal collapse in a cat has been published, but there is no literature describing this disease process in dogs. OBJECTIVE: To describe the signalment, clinical presentation, concurrent disease processes, and imaging findings of a population of client-owned dogs with pharyngeal collapse. ANIMALS: Twenty-eight client-owned dogs with pharyngeal collapse. METHODS: Radiology reports of dogs for which fluoroscopy of the respiratory system was performed were reviewed retrospectively. Patients with a fluoroscopic diagnosis of pharyngeal collapse were included in the study population. Data regarding clinical signs, diagnostic, and pathologic findings were evaluated. RESULTS: Twenty-eight dogs met the inclusion criteria. The median age of affected patients was 6.6 years, whereas median body condition score was 7/9. The most common clinical signs were coughing (n = 20) and stertor (n = 5). In 27 of 28 cases, a concurrent or previously diagnosed cardiopulmonary disorder was detected. The most common concurrent disease processes were mainstem bronchi collapse (n = 18), tracheal collapse (n = 17), and brachycephalic airway syndrome (n = 8). Fluoroscopy identified complete pharyngeal collapse in 20 of 28 dogs. CONCLUSIONS: Pharyngeal collapse is a complex disease process that likely is secondary to long-term negative pressure gradients and anatomic and functional abnormalities. Based on the findings of this study, pharyngeal fluoroscopy may be useful diagnostic test in patients with suspected tracheal and mainstem bronchial collapse to identify concurrent pharyngeal collapse.

コメント:気管および主気管支の虚脱のある犬では、透視検査にて咽頭虚脱の併発が確認されるかもしれない。また、肥満も素因もしくは悪化因子として関連しているかもしれない。8頭が短頭種、残り20頭のうち12頭はヨークシャーテリアであった(いいのペットクリニック 飯野 亮太-181228)。


Pollard RE, Johnson LR, Marks SL. The prevalence of dynamic pharyngeal collapse is high in brachycephalic dogs undergoing videofluoroscopy. Vet Radiol Ultrasound 2018;59:529-534.

ビデオ透視検査を実施した短頭犬種での動的咽頭虚脱の高い有病率

The aim of this retrospective study was to determine the frequency of pharyngeal collapse in a large group of brachycephalic dogs undergoing videofluoroscopic assessment of swallowing or airway diameter. We hypothesized that brachycephalic dogs would have pharyngeal collapse more frequently than dolichocephalic or mesocephalic dogs with or without airway collapse. The medical records database was searched for brachycephalic dogs undergoing videofluoroscopy of swallowing or airway diameter between January 1, 2006 and December 31, 2015. A cohort of dolichocephalic/mesocephalic dogs with videofluoroscopically confirmed airway collapse was age and time matched for comparison. A control group of dolichocephalic/mesocephalic dogs that did not have documented airway collapse was also evaluated. All fluoroscopic studies were assessed by a board certified veterinary radiologist for the presence and degree of pharyngeal collapse. Results demonstrate that pharyngeal collapse was significantly more common in brachycephalic dogs (58/82; 72%) than in nonbrachycephalic dogs with (7/25; 28%) and without (2/30; 7%) airway collapse. Pharyngeal collapse is more prevalent in brachycephalic dogs undergoing videofluoroscopy than in dolichocephalic/mesocephalic dogs with or without airway collapse.

コメント:長頭/中頭犬種を比較対照とした、短頭犬種大規模グループでの透視検査による咽頭虚脱の回顧的研究。気道虚脱の有無にかかわらず、短頭犬種は長頭/中頭犬種より咽頭虚脱が多くみられる(いいのペットクリニック 飯野 亮太-181228)。


睡眠時無呼吸

ヒトの睡眠時無呼吸

一般


American Academy of Sleep Medicine : The international classification of sleep disorders, 2nded : Diagnostic and coding manual. American Academy of Sleep Medicine, Westchester, 2005

榊原博樹. 睡眠時無呼吸症候群 診療ハンドブック. 東京:医学書院, 2010

人の睡眠時無呼吸の概要について

用語解説

  • 無呼吸(apnea):成人では呼吸気流の停止〜基準振幅の10%未満が10秒以上持続したイベント。乳幼児、小児では持続時間を2呼吸サイクル分の時間とする。
  • 低呼吸(hypopnea):換気量が規定以上に減少した状態。人ではresearch definitionおよびclinical definitionと呼ばれる2つの診断基準がある。research definitionでは3%以上の酸素飽和度低下あるいは覚醒反応を伴う呼吸気流の減少を低呼吸とする(ほとんどの施設がこの基準を採用)。clinical definitionでは呼吸気流の30%以上の減少に、4%以上の酸素飽和度低下を伴うイベントを低呼吸とする。
  • 無呼吸指数(apnea index AI):全睡眠時間(total sleep time TST)1時間当たりの無呼吸の回数
  • 無呼吸低呼吸指数(apnea hypopnea index AHI):TST1時間当たりの無呼吸+低呼吸の回数
  • 睡眠呼吸障害(sleep disordered breathing SDB):睡眠時の無呼吸および低呼吸、あるいは酸素飽和度の低下を伴う呼吸異常のことで、症状の有無は問わない。
  • 睡眠時無呼吸(sleep apnea SA)
  • 閉塞型睡眠時無呼吸(obstructive sleep apnea OSA):上気道閉塞による睡眠時無呼吸。呼吸気流の停止は見られるが、胸腹部の呼吸運動は残存している。
  • 中枢型睡眠時無呼吸(central sleep apnea CSA):呼吸中枢からの呼吸刺激出力の停止による睡眠無呼吸。呼吸気流の停止とともに、胸腹部の呼吸運動も停止する。
  • 混合型睡眠時無呼吸(mixed sleep apnea MSA):CSAに続いてOSAが生じる無呼吸
  • 閉塞型睡眠時無呼吸症候群(obstructive sleep apnea syndrome OSAS):1時間に5〜10以上のOSA主体のSDBが見られるSAS
  • 中枢型睡眠時無呼吸症候群(central sleep apnea syndrome CSA):1時間に5〜10以上のCSA主体のSDBが見られるSAS
  • 睡眠呼吸異常症(sleep breathing disorder SBD):SASに加えて、上気道抵抗症候群、いびき、肥満低換気症候群など睡眠時の呼吸異常を広く組み入れた概念のこと

OSASの概念

1時間に5〜10以上のOSA主体のSDBが見られるSAS。長時間継続すると徐々にPaCO2が上昇するが、覚醒によってほとんどが終了する。

OSASの診断基準は以下の二つである。(AASM 2005)

1 A+B+D

2 C+D

A   少なくとも以下の1項目を満たす

  • 覚醒時の睡眠発作、昼間の眠気、熟睡感欠如、倦怠感、不眠
  • 呼吸停止、喘ぎあるいは窒息館とともに覚醒
  • ベッドパートナーによる大きないびきや呼吸停止の報告

B   終夜睡眠ポリグラフ検査による以下の所見を満たす

  • AHI ≧ 5
  • 各呼吸イベントの全てあるいは一部で呼吸努力が確認される

C   終夜睡眠ポリグラフ検査による以下の所見を満たす

  • AHI ≧ 15
  • 各呼吸イベントの全てあるいは一部で呼吸努力が確認される

D   他の睡眠障害、医学的あるいは神経学的異常、治療薬や薬物と関連した異常では説明できない

コメント:人では睡眠時無呼吸は特殊なモニター機器を終夜装着し、睡眠状態を記録して上記のような指標を算出して診断される。低呼吸については診断基準が2つあり、目的によって使い分けられている(乙訓どうぶつ病院 中森正也-2018.11.27)


 

閉塞性睡眠時無呼吸症候群(OSAS)


磯野史朗. 【睡眠時無呼吸 最近の進歩と展望】 睡眠時無呼吸の病態生理と呼吸調節 閉塞型睡眠時無呼吸 咽頭閉塞とその周期性のメカニズム. 最新医学 2009;64:14-21.

閉塞型睡眠時無呼吸(OSA)の病態は,依然としてすべてが解明されたわけではない.肥満あるいは顎顔面形態異常による咽頭周囲の解剖学的アンバランスが,咽頭閉塞性を増加させることは確かなようである.さらに,特に肥満OSA患者では,肺容量減少が咽頭閉塞性増加に大きく寄与しているようである.呼吸器系の不安定性が高い患者では,OSAを周期的に繰り返し重症化しやすいと考えられている.(著者抄録)

コメント:


 

中枢性睡眠時無呼吸症候群(CSAS)


掲載準備中


 

乳幼児突然死症候群(SIDS)


磯野史朗. ピットフォール 乳幼児突然死症候群(SIDS)の病態生理 最近の概念. 呼吸(0286-9314) 2012;31:259-263.

乳幼児突然死症候群(SIDS)発症の病態は依然として解明されていないが、閉塞型睡眠時無呼吸(OSA)とSIDSとの関連性が強く支持されている。通常OSAは致死的な疾患ではないが、OSAから回復し呼吸を再開する生体防御過程が障害されることでSIDSへ進展する可能性がある。SIDS乳児は、巨舌・小顎などの咽頭閉塞性を高める解剖学的特徴を有し、事実SIDS乳児は生前OSAの頻度が正常乳児よりも多いことが判明した。このような解剖学的特徴を有しない場合でも、うつぶせによって咽頭閉塞性が増加し神経性代償が働かない状況ではOSAを発症する可能性もある。SIDSあるいはALTE乳児では、呼吸の化学調節系、覚醒反応、自律神経機能などの障害を示唆する報告も多い。今後の研究の進展が期待されるとともに、乳児におけるOSAの診断と治療の重要性が広く認識されるべきと考える。(著者抄録)

コメント:


 

犬の睡眠時無呼吸

城下幸仁, 山本洋史, 松田岳人ら. 犬の睡眠時無呼吸症と考えられた5例. 第30回動物臨床医学会年次大会プロシーディング 2009:159-160.

コメント:重度な無呼吸症状を呈した合計6例報告。4例が永久気管切開術にて治療しQOL改善をえられた。4例中3例は非短頭種であった(犬・猫の呼吸器科 城下-2018.11.29)


城下幸仁. 【犬と猫の睡眠】 睡眠時無呼吸症. MVM 2018;27:26-37.

コメント:6症例を提示した。上記報告の追跡を行なった。永久気管切開術を実施した3例はQOL良好を維持し長期生存した(1331、2761、2826日間)。犬の睡眠時無呼吸症の診断基準を以下のように定義した。

  • 睡眠時に閉塞性無呼吸がある(2呼吸以上もしくは10秒以上)
  • 無呼吸発作関連症状が認められる
  • 覚醒時頭部X線または透視検査にて咽頭閉塞を認める

上記、全てを満たす。

(犬・猫の呼吸器科 城下-2018.11.28)。


Hinchliffe TA, Liu NC, Ladlow J. Sleep-disordered breathing in the Cavalier King Charles spaniel: A case series. Vet Surg 2018. http://doi org/10.1111/vsu.13148  (PDF)

キャバリア・キング・チャールズの睡眠呼吸障害の5例

OBJECTIVE: To describe sleep-disordered breathing (SDB) in the Cavalier King Charles spaniel (CKCS).

STUDY DESIGN: Retrospective case series.

ANIMALS: Five client-owned dogs referred for SDB.

METHODS: Medical records were reviewed including recheck appointments and routine preoperative and postoperative questionnaires. Whole-body barometric plethysmography was used to categorize SDB.

RESULTS: All dogs presented with multiple episodes of stertorous breathing, choking, and apnea during sleep. Severe nasal septal deviation, aberrant nasal turbinates, and soft palate elongation and thickening were noted on computed tomography and rhinoscopy of each dog. Whole-body barometric plethysmography measurements during sleep (in 3 dogs) documented periods of choking, snoring, and apnea. Treatment combined laser turbinectomy, folding flap palatoplasty, tonsillectomy, laryngeal sacculectomy, and cuneiform process resection. All dogs improved in terms of incidence and severity of sleep apnea within 1 week, with 4 of 5 dogs achieving complete resolution.

CONCLUSION: The objective measurements used to characterize SDB in this population of CKCS provided some evidence to support an obstructive cause for this condition, which improved with surgical treatment.

CLINICAL SIGNIFICANCE: Sleep-disordered breathing in the CKCS is a different clinical presentation of brachycephalic obstructive airway syndrome. Our finding of intranasal abnormalities in these 5 dogs with SDB provides justification for future research into its clinical significance.

コメント:(報告概要)睡眠時呼吸障害を示したキャバリア5例の後ろ向き記述研究。問診票で治療前後の主観評価、睡眠中の体プレチスモグラフィーをもちいて睡眠呼吸障害の客観的分類を試みた。5例全ての犬が睡眠中いびき呼吸、無呼吸、息がつまるといった経験を複数回経験していた。重度の鼻中隔の変位、鼻甲介の変形、軟口蓋の肥厚・過長がそれぞれの犬でCTや鼻鏡検査で明らかになった。3頭で睡眠中の体プレチスモグラフィーで息詰まり、いびき、無呼吸が計測された。治療はレーザーでの鼻甲介切除術、軟口蓋形成術、扁桃切除、喉頭小嚢切除、楔状突起の切除の組み合わせで行われた。1週間以内に無呼吸の重症度と頻度が改善され、5頭中4頭が完全に寛解した。

この犬種における睡眠時呼吸障害は外科的な治療によって寛解したため、上部気道閉塞が原因である可能性が高いと考えられる。キャバリアはキアリ奇形と心臓病の好発犬種であり、中枢性の睡眠時無呼吸との関連、心不全と睡眠時無呼吸との関連など今後の研究対象として興味深い(ぬのかわ犬猫病院-布川智範-2019.1.2)。


 

犬の咽頭閉塞と周術期リスク


城下幸仁. 時間軸で考える短頭種気道症候群. 中島尚志編集. 時間軸で考える獣医外科病態生理学. 東京: インターズー, 2018;24-37.

コメント:ある学会後のアンケートで全回答者の30%が短頭種の麻酔後死亡事故を経験していた(犬・猫の呼吸器科 城下-2018.11.28)


Gruenheid M, Aarnes TK, McLoughlin MA, et al. Risk of anesthesia-related complications in brachycephalic dogs. J Am Vet Med Assoc 2018;253:301-306.   (PDF)

短頭犬種における麻酔関連合併症のリスク

OBJECTIVE To determine whether brachycephalic dogs were at greater risk of anesthesia-related complications than nonbrachycephalic dogs and identify other risk factors for such complications. DESIGN Retrospective cohort study.

ANIMALS 223 client-owned brachycephalic dogs undergoing general anesthesia for routine surgery or diagnostic imaging during 2012 and 223 nonbrachycephalic client-owned dogs matched by surgical procedure and other characteristics.

PROCEDURES Data were obtained from the medical records regarding dog signalment, clinical signs, anesthetic variables, surgery characteristics, and complications noted during or following anesthesia (prior to discharge from the hospital). Risk of complications was compared between brachycephalic and nonbrachycephalic dogs, controlling for other factors.

RESULTS Perianesthetic (intra-anesthetic and postanesthetic) complications were recorded for 49.1% (n = 219) of all 446 dogs (49.8% [111/223] of brachycephalic and 48.4% [108/223] of nonbrachycephalic dogs), and postanesthetic complications were recorded for 8.7% (39/446; 13.9% [31/223] of brachycephalic and 3.6% [8/223] of nonbrachycephalic dogs). Factors associated with a higher perianesthetic complication rate included brachycephalic status and longer (vs shorter) duration of anesthesia; the risk of perianesthetic complications decreased with increasing body weight and with orthopedic or radiologic procedures (vs soft tissue procedures). Factors associated with a higher postanesthetic complication rate included brachycephalic status, increasing American Society of Anesthesiologists status, use of ketamine plus a benzodiazepine (vs propofol with or without lidocaine) for anesthetic induction, and invasive (vs noninvasive) procedures.

CONCLUSIONS AND CLINICAL RELEVANCE Controlling for other factors, brachycephalic dogs undergoing routine surgery or imaging were at higher risk of peri- and postanesthetic complications than nonbrachycephalic dogs. Careful monitoring is recommended for brachycephalic dogs in the perianesthetic period.

コメント:(論文概要)短頭種は他の犬種よりも麻酔の周術期リスクがあることを確認するため、オハイオ州立大学で2012年1月から12月まで手術や画像診断のために全身麻酔を受けた非短頭種と短頭種の診療記録をもとにしたマッチドケースコンロール研究。ASA分類のⅠ~ Ⅲを対象とし、麻酔前危険度評価の高いⅣ~Ⅴは除外した。多変量ロジスティック回帰分析にてリスクファクターを抽出した。本研究では非短頭種と比べ、短頭種の麻酔中の合併症は1.57倍で周術期では4.33倍であった。全体の周術期の合併症は49.1%(n=219/全446頭中)で麻酔中の合併症は40.4%(n=180)手術後の合併症は8.7%(n=39)だった。短頭種は上記の順に49.8%(n=111)49.3%(n=110)13.9%(n=31)で非短頭種では順に48.4%(n=108)48.9%(n=109)3.6%(n=8)だった。術後の合併症で最も一般的なのは誤嚥性肺炎で9頭の短頭種(4.0%)で非短頭種ではなかった。麻酔リスクの低い症例を選択したにもかかわらず、短頭犬種で2例の周術期死亡例があった。1例の短頭種は硝子体内ゲンタマイシン注入の為、プロポフォールで麻酔導入中に心停止を起こした。もう1例の短頭種はビルロート2型の手術後4日で死亡した。この症例は朝処置の間に呼吸が止まり、心停止を起こした。短頭種犬は非短頭種と比較して周術期に合併症のリスクが今回の研究では高く、特に麻酔後に顕著であった。抜管時に気道閉塞が起こり得るため、麻酔中よりもむしろ麻酔後に合併症がより起きやすい傾向にある。

短頭種は麻酔のリスクが高いということを論文で出したことに大きな意義がある。短頭種気道症候群の重症度に分類したオッズ比のデータがないことは残念。ASA分類Ⅱに分類している短頭種がASAⅡよりも麻酔の合併症のリスクが高いので、Ⅱ以上に分類すべきだと思う(ぬのかわ犬猫病院-布川智範-2019.1.2)。


 

非外科群の生存期間やQOL評価


掲載準備中


 

非短頭種の咽頭閉塞性疾患「咽頭気道閉塞症候群、Pharyngeal airway obstruction syndrome (PAOS)」


城下幸仁、稲葉健一:咽頭気道閉塞症候群89例. 第39回動物臨床医学会年次大会プロシーディングno.3  2018:18-22.

非短頭犬種では、頭部X線検査で短頭犬種とは異なる咽頭気道の構造異常があることに着目し、咽頭気道閉塞症候群を定義した。当院呼吸器科4年間の診療記録からこの画像所見を示す89例を抽出し、臨床像、治療、転帰について後向きに調査した。犬種では、ポメラニアン、ヨークシャー・テリア、チワワで好発し、発症年齢中央値は9歳であり、主訴では慢性咳嗽、徴候では肥満、最終診断では気管虚脱が最も多かった。治療は約半数で体重減量が処方され3ヶ月後にはその86.7%で初期症状は改善した。一方、進行例では睡眠時無呼吸や陰圧性肺水腫を発症し、特に後者では60日生存率が66.7%であった。早期に本疾患を認識し減量治療を開始すべきである。

コメント:2009.1~2013.10の犬・猫の呼吸器科(旧:相模が丘動物病院 呼吸器科)初診全例を対象とした。データ集計後、5年が経過しているが、本研究結果の矛盾する所見は未だに得られておらず、犬の上気道閉塞の一疾患としてのentityとして妥当であると考えられる(犬・猫の呼吸器科 城下-2018.11.28)。


 

肥満と咽頭気道(ヒト)

Lopata M, Onal E. Mass loading, sleep apnea, and the pathogenesis of obesity hypoventilation. Am Rev Respir Dis1982;126:640-645.  

体脂肪、睡眠時無呼吸と、肥満低換気症候群の病因との関係

To define the roles of mechanical loading, respiratory neuromuscular control, and sleep apnea in the pathogenesis of obesity hypoventilation, respiratory muscle drive and output, assessed by diaphragmatic electromyogram (EMGdi) and mouth occlusion pressure (P 0.15), respectively, were determined during CO2 chemostimulation in nonobese volunteers who were subjected to abdominal mass loading, and in three groups of markedly obese patients: eucapnic obese without sleep apnea (O), eucapnic obese with sleep apnea (OSA), and hypercapnic obese with sleep apnea (OH). The P0.15 responses were decreased in OSA and OH, but the EMGdi responses were not significantly different from those in control subjects. In O patients EMGdi responses were significantly greater than those in control subjects as well as those in OSA and OH patients. EMGdi and P0.15 responses increased in all nonobese subjects when they were subjected to mass loading. We conclude that both OSA and OH patients were equally unable to develop the expected increase in respiratory muscle drive and output. The presence of sleep apnea, possibly by causing nocturnal hypoxemia and/or sleep fragmentation, may result in impaired mass load compensation and predispose obese patients to develop hypercapnia.

 コメント:肥満低換気症候群(OHS)では、低O2換気応答、高CO2換気応答とも抑制されているが、気管切開やCPAPなどの治療により正常化することから、低酸素血症や高炭酸ガス血症、呼吸筋疲労などが関与して二次的に発生したものと考えられている(犬・猫の呼吸器科 城下-2018.11.28)。


Horner RL, Mohiaddin RH, Lowell DG, et al. Sites and sizes of fat deposits around the pharynx in obese patients with obstructive sleep apnoea and weight matched controls. Eur Respir J1989;2:613-622.

OSAS肥満患者と非OSAS肥満患者における咽頭周囲の脂肪沈着の部位と量の比較

 It has been suggested that deposition of fat in the soft tissues surrounding the upper airway may be an important factor in the pathogenesis of obstructive sleep apnoea (OSA) in obese subjects. We have used magnetic resonance imaging to determine the site(s) and size(s) of fat deposits around the upper airway in six obese patients with OSA (116-153% of ideal body weight) and five weight-matched controls without OSA (107-152% of ideal body weight). In all subjects, large deposits of fat were present postero-lateral to the oropharyngeal airspace at the level of the soft palate. Significantly more fat was present in these regions in the patients with OSA (p = 0.03). Fat deposits in the soft palate were observed in 4 of the 6 patients with OSA but none of the controls. Fatty streaks were observed in the tongue in 2 of the 5 controls and 3 of the 6 patients with OSA. Fat deposits were observed anterior to the laryngopharyngeal airspace, in submental regions, in all obese subjects. This study shows that more fat is present in those areas surrounding the collapsible segment of the pharynx in patients with OSA, compared to equally obese control subjects without OSA.

コメント:MRI検査にて、肥満でOSASと診断された患者(n=6)には、同じ肥満で非OSASの患者(n=5)に比べ上気道への脂肪沈着が高度であった。軟口蓋への脂肪沈着はOSASのみにみられ、喉頭咽頭より前の顎下領域への脂肪沈着はOSAS患者に特徴的であった(犬・猫の呼吸器科 城下-2018.11.28)。


Ryan CF, Love LL. Mechanical properties of the velopharynx in obese patients with obstructive sleep apnea. Am J Respir Crit Care Med1996;154:806-812.

OSAを示す肥満患者における後咽頭のメカニクス特性について

Epidemiologic data indicate that the relationship between obesity and obstructive sleep apnea (OSA) is largely explained by variation in neck size. Fat deposits in the neck may predispose to upper airway (UA) occlusion during sleep by altering the mechanical properties of the UA, particularly at the level of the velopharynx (VP). To determine whether effective compliance (CEFF) of the VP is related to obesity in the neck, we have performed anthropometrics, polysomnography, and dynamic UA videoendoscopy in 18 patients with OSA and eight nonapneic control subjects. Following topical anesthesia (cocaine 4%) to one nasal passage, subjects were examined with a thin fiberscope (outer diameter [OD] 3.8 mm) while awake, supine, breathing exclusively through the nose, during a maximal vital capacity (VC) maneuver against an unoccluded airway. UA cross-sectional area (CSA), anteroposterior (AP) and lateral (L) diameters were measured from stored images. CEFF was expressed as the ratio of CSAVP in expiration (E) to inspiration (I) during the maximal VC maneuver (expiratory CSAMAX/inspiratory CSAMIN), and airway shape as AP/L diameter. The OSA patients were divided into two groups based on median neck circumference (NC). CEFF of the VP was greater in OSA patients compared with control subjects (CEFF 2.0 +/- 0.8 versus 1.1 +/- 0.5; p < 0.001). CEFF was greater in the large NC group compared with both the small NC group (p < 0.05) and control subjects (p < 0.01), but the difference between the small NC group and control subjects was not significant. CEFF was related to NC (r = 0.63; p = 0.001; n = 26), body mass index (r = 0.54; p < 0.01, n = 26), and apnea-hypopnea index (r = 0.43; p < 0.05; n = 23). The change in CSAVP during the maximal VC maneuver was mainly due to inspiratory narrowing. Obese patients with large necks have a more collapsible velopharynx during wakefulness, which may predispose to upper airway obstruction during sleep.

コメント:首回りが太い肥満患者では、覚醒期でも後咽頭は虚脱しやすく、それは睡眠時の上気道閉塞を生じやすいことを示唆するものである(犬・猫の呼吸器科 城下-2018.11.28)。


Peppard PE, Young T, Palta M, et al. Longitudinal study of moderate weight change and sleep-disordered breathing. JAMA2000;284:3015-3021.

体重変化と睡眠呼吸障害との関連についての縦断研究

CONTEXT: Excess body weight is positively associated with sleep-disordered breathing (SDB),a prevalent condition in the US general population. No large study has been conducted of the longitudinal association between SDB and change in weight. OBJECTIVE: To measure the independent longitudinal association between weight change and change in SDB severity. DESIGN: Population-based, prospective cohort study conducted from July 1989 to January 2000. SETTING AND PARTICIPANTS: Six hundred ninety randomly selected employed Wisconsin residents (mean age at baseline, 46 years; 56% male) who were evaluated twice at 4-year intervals for SDB. MAIN OUTCOME MEASURES: Percentage change in the apnea-hypopnea index (AHI; apnea events + hypopnea events per hour of sleep) and odds of developing moderate-to-severe SDB (defined by an AHI > or =15 events per hour of sleep), with respect to change in weight. RESULTS: Relative to stable weight, a 10% weight gain predicted an approximate 32% (95% confidence interval [CI], 20%-45%) increase in the AHI. A 10% weight loss predicted a 26% (95% CI, 18%-34%) decrease in the AHI. A 10% increase in weight predicted a 6-fold (95% CI, 2.2-17.0) increase in the odds of developing moderate-to-severe SDB. CONCLUSIONS: Our data indicate that clinical and public health programs that result in even modest weight control are likely to be effective in managing SDB and reducing new occurrence of SDB.

コメント:体重が10%増えるとAHI(無呼吸-低呼吸指数)>15/hになるオッズ比が6.0になり、20%増えると36.6にも増大する(犬・猫の呼吸器科 城下-2018.11.28)。


Namyslowski G, Scierski W, Mrowka-Kata K, et al. Sleep study in patients with overweight and obesity. J Physiol Pharmacol2005;56 Suppl 6:59-65.

肥満患者における睡眠研究パラメーター

 Obstructive sleep apnea syndrome (OSAS) is a disorder characterized by repetitive collapse of the pharyngeal airway during sleep, which leads to oxygen desaturation, sleep fragmentation and daytime somnolence. Obesity is one of the most important risk factor for the development of OSAS. The exact mechanisms responsible for the relationship between obesity and OSAS are still unclear. The fat deposits in the pharynx region as well as the reduction in the lung volume have been considered as factors that might be responsible for the increase of the upper airway collapsibility. The aim of our study was to evaluate the correlation between the Body Mass Index (BMI) and sleep study parameters in overweight and obese patients suffering from breathing disturbances during sleep. In all cases, BMI and sleep studies (PolyMESAM) were examined. We evaluated relationship between the BMI and sleep study parameters such as Respiratory Disturbance Index (RDI), Apnea Index (AI), Desaturation Index (DI) and Average of Lowest Saturation (LSAT). The results showed the lack of significant statistical correlations between BMI and all the sleep parameters studied in the overweight patients and the statistical positive correlation between the BMI and RDI in the obese cases. We conclude that BMI determination may be considered as a simple, yet important predictor, of the OSAS in the group of obese patients.

コメント:BMI値は、肥満患者のOSAS評価として予測ほど重要な決定因子ではない(犬・猫の呼吸器科 城下-2018.11.28)。


榊原博樹. 睡眠呼吸障害. 日本呼吸器学会肺生理専門委員会編集. 臨床呼吸機能検査 第7版. 東京: メディカルレビュー社, 2008;224-245.

文中引用 「肥満者の全てがOSASを発症する訳ではない。種々の要因によりもともと上気道の狭い者が肥満するとOSASを発症するのである。」


磯野史朗. 【睡眠時無呼吸 最近の進歩と展望】 睡眠時無呼吸の病態生理と呼吸調節 閉塞型睡眠時無呼吸 咽頭閉塞とその周期性のメカニズム. 最新医学2009;64:14-21.

閉塞型睡眠時無呼吸(OSA)の病態は,依然としてすべてが解明されたわけではない.肥満あるいは顎顔面形態異常による咽頭周囲の解剖学的アンバランスが,咽頭閉塞性を増加させることは確かなようである.さらに,特に肥満OSA患者では,肺容量減少が咽頭閉塞性増加に大きく寄与しているようである.呼吸器系の不安定性が高い患者では,OSAを周期的に繰り返し重症化しやすいと考えられている.(著者抄録)(犬・猫の呼吸器科 城下-2018.11.28)


Brennick MJ, Pack AI, Ko K, et al. Altered upper airway and soft tissue structures in the New Zealand Obese mouse. Am J Respir Crit Care Med2009;179:158-169.     

肥満マウスの上気道とその軟部組織構造の変化

RATIONALE: The effect of obesity on upper airway soft tissue structure and size was examined in the New Zealand Obese (NZO) mouse and in a control lean mouse, the New Zealand White (NZW). OBJECTIVES: We hypothesized that the NZO mouse has increased volume of neck fat and upper airway soft tissues and decreased pharyngeal airway caliber. METHODS: Pharyngeal airway size, volume of the upper airway soft tissue structures, and distribution of fat in the neck and body were measured using magnetic resonance imaging (MRI). Dynamic MRI was used to examine the differences in upper airway caliber between inspiration and expiration in NZO versus NZW mice. MEASUREMENTS AND MAIN RESULTS: The data support the hypothesis that, in obese NZO versus lean NZW mice,airway caliber was significantly smaller (P < 0.03), with greater parapharyngeal fat pad volumes (P < 0.0001) and a greater volume of other upper airway soft tissue structures (tongue, P = 0.003; lateral pharyngeal walls, P = 0.01; soft palate, P = 0.02).Dynamic MRI showed that the airway of the obese NZO mouse dilated during inspiration, whereas in the lean NZW mouse, the upper airway was reduced in size during inspiration. CONCLUSIONS: In addition to the increased volume of pharyngeal soft tissue structures, direct fat deposits within the tongue may contribute to airway compromise in obesity. Pharyngeal airway dilation during inspiration in NZO mice compared with narrowing in NZW mice suggests that airway compromise in obese mice may lead to muscle activation to defend upper airway patency during inspiration.

コメント: Dynamic MRI検査。正常マウスに比べ、肥満マウスでは、咽頭周囲脂肪組織が有意に増加した(P < 0.0001)。上気道内構造では、舌(P=0.003)と咽頭側壁(P=0.01)と軟口蓋(P=0.02)の容積が増加し、咽頭気道径が減少した。さらに、吸気時に、正常マウスの咽頭は咽頭気道径が縮小したのに対し、肥満マウスは咽頭気道が拡張した。肥満マウスでは、上気道開存を維持するため、上気道開大筋活動によって代償している(犬・猫の呼吸器科 城下-2018.11.28)。


Kim AM, Keenan BT, Jackson N, et al. Tongue fat and its relationship to obstructive sleep apnea. Sleep2014;37:1639-1648.

舌の脂肪はOSAと関連する

STUDY OBJECTIVES: The objective of this study was to determine whether tongue fat is increased in obese sleep apneics compared to obese subjects without sleep apnea. We hypothesized that excess fat is deposited in the tongue in obese patients with sleep apnea. DESIGN: Case-control design. SETTING: Academic medical center. PATIENTS: We examined tongue fat in 31 obese controls (apnea-hypopnea index, 4.1 +/- 2.7 events/h) and 90 obese apneics (apnea-hypopnea index, 43.2 +/- 27.3 events/h). Analyses were repeated in a subsample of 18 gender-, race-, age-, and BMI-matched case-control pairs. INTERVENTIONS: All subjects underwent a MRI with three-point Dixon magnetic resonance imaging. We used sophisticated volumetric reconstruction algorithms to study the size and distribution of upper airway fat deposits in the tongue and masseter muscles within apneics and obese controls. MEASUREMENTS AND RESULTS: The data supported our a priori hypotheses that after adjustment for age, BMI, gender, and race, the tongue in apneics was significantly larger (P = 0.001) and had an increased amount of fat (P = 0.002) compared to controls. Similar results were seen in our matched sample. Our data also demonstrate that within the apneic and normal tongue, there are regional differences in fat distribution, with larger fat deposits at the base of the tongue. CONCLUSIONS: There is increased tongue volume and deposition of fat at the base of tongue in apneics compared to controls. Increased tongue fat may begin to explain the relationship between obesity and obstructive sleep apnea.

コメント:SAがない肥満患者に比べ、SAがある肥満患者は舌の容積が脂肪沈着によって有意に増大していた。肥満とOSAの関連は、舌への脂肪沈着によって説明できるかもしれない(犬・猫の呼吸器科 城下-2018.11.28)。


 

肥満と咽頭気道(犬)

PubMed検索

Upper Airway, fat deposits: 12 refs

Upper Airway, fat deposits, dog: 0 refs

Upper Airway, fat deposits, veterinary: 0 refs

肥満犬の上気道への脂肪沈着との関連を示した学術論文は獣医学では見当たらなかった(検査日:2018.10.31)。以下、逸話的記述をまとめた。


Hawkins EC. Pulmonary parenchymal diseases In: Ettinger SJ,Feldman EC, eds. Textbok of Veterinary Internal Medicine. 5th ed. Philadelphia, 2000;1061-1091.

The benefical effects of weight reduction in animals with chronic bronchial or pulmonary disease can be dramatic.”

コメント:人の「肥満低換気症候群(obesity-hypoventilation syndrome, OHS)=Pickwickian Syndrome」と関連付けて、肺実質疾患と肥満との関連について経験的に記載していた(犬・猫の呼吸器科 城下-2018.11.28)。


Wolfsheimer KJ. Obesity In: Ettinger SJ,Feldman EC, eds. Textbok of Veterinary Internal Medicine. 5th ed. Philadelphia, 2000;70-72.

コメント:「肥満とは、ある動物種や性別や種類の適正体重より10-20%以上である場合をいう。肥満動物では、胸郭内脂肪沈着と腹部脂肪による横隔膜の前方変位によって肺の大きさが制限されるので、肺気量が減少する。さらに過度な脂肪は、酸素需要や心拍出量が増加し、これが既存の肺疾患を悪化させる。」と記載していた(犬・猫の呼吸器科 城下-2018.11.28)


Kuehn NF. Chronic Bronchitis in Dogs In: King LG, ed. Textbook of Respiratory Disease in Dogs and Cats. St.Louis: SAUNDERS, 2004;379-387.

コメント:犬の慢性気管支炎では、肥満をよく伴い、その慢性咳のコントロールには体重管理を考慮すべきと考えられる、と記載していた(犬・猫の呼吸器科 城下-2018.11.28)


Mason RA. Tracheal hypoplasia In: King LG, ed. Textbook of Respiratory Diseases in Dogs and Cats. St.Louis: SAUNDERS, 2004;356-359.

コメント:気管低形成の補助療法として肥満犬には減量が有効であるかもしれない、と記載していた(犬・猫の呼吸器科 城下-2018.11.28)


Hendrick JC. Sleep Disorders In: Ettinger SJ,Feldman EC, eds. Textbook of Veterinary Internal Medicine. 6th ed. St. Louis, MO: Elsevier Saunders, 2005;176-181.

Similar signs as BAS associated sleep apnea have been described by owners of Shar Peis, pugs, beagles, and an obese, hypothyroid miniature poodle with obvious upper airway narrowing due to fat accumulation. This anecdotal evidence suggests that sleep apnea exists in several canine breeds.

コメント:脂肪沈着によって明らかに上気道の狭窄が生じている犬では、BASと同様に睡眠時無呼吸が生じることが飼い主たちからは確認されている。このようなまだ報告されていない情報ではあるが、いくつかの犬種では睡眠時無呼吸が生じるようである、と記載していた(犬・猫の呼吸器科 城下-2018.11.28)


Remillard RL. Obesity In: Ettinger SJ,Feldman EC, eds. Textbook of Veterinary Internal Medicine. 6th ed. St. Louis, MO: Elsevier Saunders, 2005;76-78.

コメント:肥満動物では、呼吸困難やうっ血性心不全がよく認められる。BCS 4-5/9の犬は、同じように生活し同じ食事を食べているBCS 6-7/9の犬より、15%長生きした、と記載していた(犬・猫の呼吸器科 城下-2018.11.28)


 

短頭種気道症候群への外科療法 外科適応基準と術式選択、非外科適応の判断


城下幸仁. 短頭種気道症候群の治療 病態生理に基づく周術期管理と術式選択. 日本獣医麻酔外科学雑誌 2016;47:104-107.

コメント:喉頭虚脱ステージ3は永久気管切開術選択の理由にはならない(犬・猫の呼吸器科 城下-2018.11.28)。


 

非外科適応群に対する温存対処法としてのネブライザー療法の効果


掲載準備中


 

中耳炎との関連

「キャバリアの原発性分泌性中耳炎」あるいは「キャバリアの浸出性中耳炎」

 Stern-Bertholtz W, Sjostrom L, Hakanson NW. Primary secretory otitis media in the Cavalier King Charles spaniel: a review of 61 cases. J Small Anim Pract2003;44:253-256. 

キャバリア・キング・チャールズの原発性分泌性中耳炎61例

Sixty-one episodes of primary secretory otitis media (PSOM) were diagnosed in 43 Cavalier King Charles spaniels over a 10-year period. The principal findings were signs of moderate to severe pain localised to the head or cervical area, and/or neurological signs. Diagnosis was made by examination of the tympanic membrane and middle ear with the aid of an operating microscope under general anaesthesia. A bulging, but intact, tympanic membrane was found in most cases. Following myringotomy, a highly viscous mucus plug was found filling the middle ear. Treatment, consisting of removal of the mucus plug, flushing of the middle ear, and local and systemic medical therapy, had to be repeated between one and five times. The prognosis was good in all cases. PSOM is an important differential diagnosis in Cavalier King Charles spaniels with signs of pain involving the head and neck, and/or neurological signs.

コメント:キャバリアには特発性に中耳内に浸出液が貯留する疾患があるようです。痛みや神経症状と伴い、耳鏡手術を繰り返して治療します(犬・猫の呼吸器科 城下-2018.11.28)


Hayes GM, Friend EJ, Jeffery ND. Relationship between pharyngeal conformation and otitis media with effusion in Cavalier King Charles spaniels. Vet Rec2010;167:55-58.  

キャバリア・キング・チャールズの咽頭構造と中耳内浸出液との関連

Otitis media with effusion (OME) is a common incidental finding in otherwise normal Cavalier King Charles spaniels (CKCS). In this study, measurements made on MRI were used to determine whether there was an association between OME and brachycephalic conformation. The results confirm that association and also demonstrate that, in CKCS, greater thickness of the soft palate and reduced nasopharyngeal aperture are significantly associated with OME. These results suggest that auditory tube dysfunction and OME may represent a previously overlooked consequence of brachycephalic conformation in dogs.

コメント:軟口蓋の著しく肥厚し、鼻咽頭が狭くなっているキャバリアに中耳内浸出液の増加があるようだ(犬・猫の呼吸器科 城下-2018.11.28)


Harcourt-Brown TR, Parker JE, Granger N, et al. Effect of middle ear effusion on the brain-stem auditory evoked response of Cavalier King Charles Spaniels. Vet J2011;188:341-345.  

キャバリアの中耳内浸出液の脳幹聴覚誘起反応に対する影響

Brain-stem auditory evoked responses (BAER) were assessed in 23 Cavalier King Charles Spaniels with and without middle ear effusion at sound intensities ranging from 10 to 100 dB nHL. Significant differences were found between the median BAER threshold for ears where effusions were present (60 dB nHL), compared to those without (30 dB nHL) (P=0.001). The slopes of latency-intensity functions from both groups did not differ, but the y-axis intercept when the x value was zero was greater in dogs with effusions (P=0.009), consistent with conductive hearing loss. Analysis of latency-intensity functions suggested the degree of hearing loss due to middle ear effusion was 21 dB (95% confidence between 10 and 33 dB). Waves I-V inter-wave latency at 90 dB nHL was not significantly different between the two groups. These findings demonstrate that middle ear effusion is associated with a conductive hearing loss of 10-33 dB in affected dogs despite the fact that all animals studied were considered to have normal hearing by their owners.

コメント:中耳内浸出液貯留が認められたキャバリアでは聴覚障害があるようだ(犬・猫の呼吸器科 城下-2018.11.28)


青木忍. 外耳・中耳からみた短頭種気道症候群.  動物臨床医学会年次大会プロシーディングno.1. 2018 :23-26.

コメント:短頭犬種の骨格形態や努力呼吸時の咽頭閉塞は、耳管の走行障害や開口部閉塞と関連し浸出性中耳炎を生じやすいと考えられる。また、さらにそれが進行すると真珠腫性中耳炎となり、外科手術でも再発しやすく難治化するかもしれない。(犬・猫の呼吸器科 城下-2018.11.28)


 

気管切開

全般

掲載準備中


 

一時的気管切開(Temporary tracheotomy)

掲載準備中


 

永久気管切開(Permanent tracheostomy)

掲載準備中


 

Tチューブ利用(T-tube)

掲載準備中