Validation of a novel point-of-care ultrasound method to assess diaphragmatic excursion.

INTRODUCTION: Point-of-care ultrasound can assess diaphragmatic function and rule in or rule out paresis of the diaphragm. While this is a useful bedside tool, established methods have significant limitations. This study explores a new method to assess diaphragmatic motion by measuring the excursion of the uppermost point of the zone of apposition (ZOA) at the mid-axillary line using a high-frequency linear ultrasound probe and compares it with two previously established methods: the assessment of the excursion of the dome of the diaphragm (DOD) and the thickening ratio at the ZOA. METHODS: This is a single-centre, prospective comparative study on elective surgical patients with normal diaphragmatic function. Following research ethics board approval and patient written consent, 75 elective surgical patients with normal diaphragmatic function were evaluated preoperatively. Three ultrasound methods were compared: (1) assessment of the excursion of the DOD using a curvilinear probe through an abdominal window; (2) assessment of the thickening fraction of the ZOA; and (3) assessment of the excursion of the ZOA. The last two methods performed with a linear probe on the lateral aspect of the chest. RESULTS: Seventy-five patients were studied. We found that the evaluation of the excursion of the ZOA was more consistently successful (100% bilaterally) than the evaluation of the excursion of the DOD (98.7% and 34.7% on the right and left sides, respectively). The absolute values of the excursion of the ZOA were greater than and well correlated with the values of the DOD. CONCLUSION: Our preliminary data from this exploratory study suggest that the evaluation of the excursion of the ZOA on the lateral aspect of the chest using a linear probe is consistently successful on both right and left sides. Future studies are needed to establish the distribution of normal values and suggest diagnostic criteria for diaphragmatic paresis or paralysis. TRIAL REGISTRATION NUMBER: NCT03225508.

Cannabinoid hyperemesis.

A 21-year-old woman presented with a 4-week history of sudden onset vomiting, nausea and anorexia. Questioning revealed that she had a 7-year history of heavy cannabis use (smoking). She did not describe abdominal pain, change in bowel habit, antibiotic use, foreign travel or contact with gastroenteritis. Biochemistry results demonstrated mild metabolic derangement with a low potassium and a low bicarbonate, and urine toxicology was positive for cannabinoids. Other investigations, including a full blood count, renal function tests, liver function tests, a coagulation sample, an ECG, urinary ß-hCG and a CT head scan, were all normal. A diagnosis of cannabinoid hyperemesis was made and her symptoms resolved after treatment with intravenous fluids, antiemetics and abstinence from cannabis. Since her discharge and abstinence she has had several relapses, each related to cannabis use and each resolving with abstinence. The patient is now seeking cognitive behavioural therapy to achieve permanent abstinence.

Cannabinoid hyperemesis.

A 21-year-old woman presented with a 4-week history of sudden onset vomiting, nausea and anorexia. Questioning revealed that she had a 7-year history of heavy cannabis use (smoking). She did not describe abdominal pain, change in bowel habit, antibiotic use, foreign travel or contact with gastroenteritis. Biochemistry results demonstrated mild metabolic derangement with a low potassium and a low bicarbonate, and urine toxicology was positive for cannabinoids. Other investigations, including a full blood count, renal function tests, liver function tests, a coagulation sample, an ECG, urinary ß-hCG and a CT head scan, were all normal. A diagnosis of cannabinoid hyperemesis was made and her symptoms resolved after treatment with intravenous fluids, antiemetics and abstinence from cannabis. Since her discharge and abstinence she has had several relapses, each related to cannabis use and each resolving with abstinence. The patient is now seeking cognitive behavioural therapy to achieve permanent abstinence.

Meningeal and brainstem infiltration by a malignant mesothelioma.

Malignant mesothelioma is an uncommon neoplasia which primarily involves the pleura or peritoneum. Central nervous system involvement is rare. A rare presentation of metastatic pleural mesothelioma, which had infiltrated the meninges and brainstem, is described. The patient presented with diplopia following a 2-week history of malaise, myalgia, mild headache and diarrhoea. Clinical examination found global areflexia, cerebellar ataxia and bilateral sixth nerve palsies. Differential diagnoses included the Miller-Fisher variant of Guillain-Barre syndrome, malignant meningitis and infectious meningitis. The patient was treated with immunoglobulins, plasmaphoresis and corticosteroids; however, he deteriorated and died 31 days after admission. Retrospective examination of the MRI of the brain found diffuse low attenuation changes within the pons and cerebral peduncles. Postmortem examination favoured a diagnosis of an early sarcomatoid malignant mesothelioma of pleural origin with leptomeningeal metastatic deposits.