Systematic use of point of care ultrasound in neurosurgical intensive care unit: a practical approach

Abstract

Background: Point of care ultrasound (POCUS) is a cost-effective, non-invasive procedure with high diagnostic reliability and therapeutic utilities. For various reasons, it is not being used routinely in neurosurgical intensive care unit (ICU). We have introduced a systematic use of POCUS in critically ill patients in our neurosurgical ICU. We have studied the various indications and benefit of using this technique.

Methods: This is a prospective, single center cohort observational study done in patients who were admitted in a tertiary neurosurgical ICU over 1 year (17^th September 2020 to 16^th September 2021). POCUS was used daily as per a standardized format for multiple purposes. A formal training to the operator was provided and standardized method of evaluation and intervention was used. Outcome was studied to understand the impact of the POCUS and difficulties encountered during its use.

Results: POCUS was used in 240 patients, including all patients for primary and secondary surveys, 192 patients (80%) for optic nerve sheath diameter (ONSD) measurement, 14 myelomeningoceles for trans-fontanelle ultrasound study, 16 post operative cases of aneurysm clipping for transcranial Doppler (TCD) study, 86 patients for deep vein thrombosis (DVT) screening, 17 for evaluation of ventriculo-peritoneal (VP) shunt functionality, 30 for transcranial defect ultrasound, 45 for chest ultrasound, 4 for evaluation of hemodynamic shock and 67 patients who had difficult cannualtion or while insertion of central venous catheter placement. POCUS was also used for difficult cannulation, central catheter placement and e-FAST scan. Significant findings were reported 129 times, which led to immediate change in management in 62 patients (25.83%) as compared to 16 patients in whom significant findings were not reported using POCUS, but management was changed using other radiological modalities (P<0.01). There was initial lag in adopting the technique, however with practice, the team developed confidence. As a result, the accuracy and time taken to perform the procedure was reduced significantly.

Conclusions: Routine systematic use of POCUS can be beneficial not only for the rapid diagnosis and prompt management of patients, but also helpful in monitoring and performing various procedures in neurosurgical ICU. Though not all modalities mentioned in standardized format was used in all patients, use of this format has helped improved training and maintain proper use of POCUS in our ICU.

Keywords: Point of care ultrasound (POCUS); neurosurgical intensive care unit (ICU); sonoscopy; ultrasonography (USG).

Figure 1

POCUS record form for neurosurgical ICU. USG, ultrasonography; DOA, date of admission; ACom, anterior communicating artery; PCom, posterior communicating artery; ACA, anterior cerebral artery; BLUE, bedside lung ultrasound in emergency; VP, ventriculo-peritoneal; CVP, central venous pressure; POCUS, point of care ultrasound; ICU, intensive care unit.

Figure 2

Placement of the probe for ONSD measurement. A clear covering (e.g., tegaderm) may be used to avoid direct contact of gel with the eyelid. This image is published with patient’s party consent. ONSD, optic nerve sheath diameter.

Figure 3

ONSD measured 0.30 cm below the globe. ONSD, optic nerve sheath diameter.

Figure 4

Placement of the probe for transfontanelle measurement. This image is published with patient’s parents consent.

Figure 5

Measurement of the size of frontal horn of left lateral ventricle. With serial monitoring, the size can be appreciated.

Figure 6

Trans fontanelle ultrasound showing dilated ventricles in a case of congenital hydrocephalus.

Figure 7

TCD measurement through a transtemporal view in Doppler mode, red/blue color suggestive of blood flow towards/away respectively, thereby suggestive of the artery. TCD, transcranial Doppler.

Figure 8

TCD measurement, the depth of artery and color suggestive of blood flow away from the probe suggestive of anterior communicating artery. Here the velocity is around 150 cm/s. TCD, transcranial Doppler.

Figure 9

Transcranial defect ultrasound with a curvilinear probe in B mode of an adult showing diffuse brain swelling with effaced lateral ventricle.

Figure 10

Transcranial defect ultrasound of an adult patient showing septations within enlarged 3rd ventricle and lateral ventricles, suggestive of hydrocephalus.

Figure 11

Transcranial defect ultrasound of a hemicraniectomy patient in whom the size of the lateral ventricle is measured. This can be compared in serial monitoring.

Figure 12

Localization of VP shunt tube and checking the flow in M mode. The flow in the VP shunt is observed distal to the chamber by pressing/releasing the chamber. VP, ventriculo-peritoneal.

Figure 13

Standardized BLUE protocol points over right side of the anterior and lateral chest wall. BLUE, bedside lung ultrasound in emergency.

Figure 14

Lung ultrasound to check for lung sliding in M mode. Here a Seashore sign can be seen which is a normal finding.

Figure 15

M mode lung ultrasound showing a Barcode sign, suggestive of pneumothorax.

Figure 16

DVT screening in M mode showing the flow in popliteal vein in M mode using a linear probe. DVT, deep vein thrombosis.

Figure 17

Checking the compressibility of the femoral vein by pressing the probe to the skin in B mode.

Figure 18

Patient selection flowchart with different POCUS based study/procedures and number of patients with additional interventions performed for abnormality detected in each POCUS modality. ICU, intensive care unit; ONSD, optic nerve sheath diameter; DVT, deep vein thrombosis; TCD, transcranial Doppler; VP, ventriculo-peritoneal; USG, ultrasonography; CVP, central venous pressure; POCUS, point of care ultrasound.