Cardiovascular observations (II)
William T. Blows in The Biological Basis of Clinical Observations, 2018
Blood pressure (BP) is an index of some of the most fundamental physiological processes in the body, and an understanding of arterial blood pressure and its measurement is essential for the accurate determination of physiological processes and disturbances. Neurogenic shock occurs when the sympathetic nervous system supply to the cardiovascular system is blocked, causing a low cardiac output, reduced peripheral resistance and venous blood pooling. Post-operative observations are critical to the patient's full recovery, and BP checks are paramount among these. Low or a falling blood pressure after surgery may indicate blood loss is occurring, either internally or externally, and should be reported and acted on quickly. The question concerning accuracy of blood pressure arises because of the possible variability that must occur within the same individual at different times and circumstances. Abnormalities of systemic blood pressure means either the pressure is too high (hypertension) or too low (hypotension).
Shock
Brice Antao, S Irish Michael, Anthony Lander, S Rothenberg MD Steven in Succeeding in Paediatric Surgery Examinations, 2017
Septic shock occasionally progresses to require increasingly aggressive treatment modalities. The paediatric intensive care unit patient has exhausted conventional therapy, including fluids, inotropy, antibiotic therapy and source control. The six-year-old child is suffering from neurogenic shock after a spinal cord injury, which is a form of distributive shock. This results in the complete loss of intravascular tone without accompanying tachycardia. After a fluid challenge, the optimal treatment of this patient is early administration of vasopressors. Dissociative shock represents an inability to deliver oxygen to the tissues. 'Cold' shock manifests as cool extremities and delayed capillary refill. Anaphylaxis is a form of distributive shock. The cardiorespiratory system is often deranged in shock states and an understanding of the basic concepts in cardiovascular physiology underpins most of the treatment decisions made in caring for patients with shock. Stroke volume is the volume of blood pumped from one ventricle of the heart with each beat.
Case 9: Head-on motor vehicle collision
Eamon Shamil, Praful Ravi, Dipak Mistry in 100 Cases in Emergency Medicine and Critical Care, 2018
This chapter presents a case study of a 35-year-old male who was the driver of a vehicle involved in a head-on collision with another vehicle. On arrival to the resuscitation area of the Emergency Department, he is confused and disorientated, unable to confirm his name or age. The patient has sustained blunt trauma that has caused cardiac tamponade, bilateral haemothoraces and hypovolaemic shock. The commonest cause in an injured patient is hypovolaemic shock due to blood loss, but other causes include cardiogenic shock due to myocardial dysfunction, neurogenic shock due to sympathetic dysfunction or obstructive shock due to obstruction of the great vessels or heart. The medical students and junior doctors should not wait for a trauma patient to develop hypotension before starting fluid replacement therapy. Ensure that the patient is haemodynamically stable before transfer to the CT scanner as transfer times may be prolonged and deterioration whilst en route or in the scanner is difficult to deal with.
Hemodynamic Parameters and Timing of Surgical Decompression in Acute Cervical Spinal Cord Injury
Published in The Journal of Spinal Cord Medicine, 2007
Sagun Tuli, Jayshree Tuli, William P. Coleman, Fred H. Geisler, Andrei Krassioukov
Background/Objectives: To evaluate the relationship between the severity of cervical spinal cord injury (SCI) (American Spinal Injury Association [ASIA] grade), presence of neurogenic shock, and timing of surgical intervention. This is a post-hoc analysis from the Sygen multicenter randomized controlled trial. Methods: Blood pressure (BP) and heart rate (HR) data were collected when patients were first assessed in the emergency room (Time A) and at the time of randomization (Time B). Individuals were subdivided by ASIA grade and by the level of the systolic BP (SBP). Results: Only individuals with cervical SCI from the Sygen trial (n = 577) were evaluated. Severe complete SCI (ASIA grade = A) was established in 57% of these patients. A total of 74 (13%) patients with neurogenic shock (SBP < 90 mmHg) at Time A were identified. The SBP increased significantly from Time A to Time B (P < 0.0001). The median time from SCI to surgical intervention, for ASIA A, was 80.9 hours for patients with initial SBP < 90 mmHg and 58 hours for patients with initial SBP > 90 mmHg (P = 0.025). Multivariable analysis after adjusting for confounders revealed a statistically significant difference in the time to surgical intervention based on SBP for ASIA A (P = 0.026), yet not for ASIA B or C/D. Conclusions: The presence of neurogenic shock was associated with a delay in the timing of surgical intervention in patients with cervical SCI. Detailed evaluation of autonomic dysfunctions following SCI including cardiovascular instability could improve our understanding of the complexities of clinical presentations and possible neurological outcomes.
Related Knowledge Centers
- Autonomic Nervous System
- Bradycardia
- Hypotension
- Sympathetic Nervous System
- Vascular Resistance
- Distributive Shock
- Shock