You're listening to the Anesthesia Patient Safety Podcast , the official podcast of the Anesthesia Patient Safety Foundation . We're bringing you the very best from the APSF newsletter and website , as well as the latest information in perioperative patient safety . Thanks for joining us .
Hello and welcome back to the Anesthesia Patient Safety Podcast . My name is Allie Bechtel and I'm your host . Thank you for joining us for another show . When was the last time that you were providing anesthesia care for a patient in the prone position ? Perhaps you positioned a patient prone for a surgical procedure earlier today , before listening to this episode .
Prone positioning is required for many different surgical procedures and , depending on your practice , may be common in the operating rooms and procedural suites where you work . This is an important time to remain vigilant , since patients are at risk for positioning injuries as well as significant physiologic changes while in the prone position .
Stay tuned for an important discussion as we review the potential injuries , highlight the physiologic changes and provide practical considerations when positioning and managing patients in the prone position . Before we dive into the episode today , we'd like to recognize GE Healthcare , a major corporate supporter of APSF .
Ge Healthcare has generously provided unrestricted support to further our vision that no one shall be harmed by anesthesia care . Thank you , ge Healthcare . We wouldn't be able to do all that we do without you . Be able to do all that we do without you . Our featured article today is an article between issues .
It is the Underappreciated Dangers of the Prone Position published on 30th April 2024 , and written by Taizun Dun and colleagues . To follow along with us , head over to apsforg and click on the newsletter heading . The second one down is articles between issues and from here scroll down until you get to our featured article today .
I will include a link in the show notes as well . Our case is just about to get underway . The patient is under general anesthesia , the endotracheal tube is in place and we have just positioned our patient prone . What is the patient at risk for due to being in the prone position ? Let's start by reviewing pressure-related injuries .
These are injuries from direct pressure with excessive strain on areas of the body that are not used to this sustained stress or load . The resulting injury may be from the direct pressure load or indirect damage due to decreased arterial blood flow or obstructed venous outflow , leading to ischemia or edema .
Other types of pressure-related injuries occur due to friction from slight body movements , leading to skin damage or blistering on the head and face or extremities . Vulnerable areas include the eyes , nose , cheekbones and cheeks , forehead , chest , arms , breasts , genitalia and pelvis , including the superior iliac spines , knees and feet .
Have you ever seen a shoulder dislocation from repositioning prone ? This may occur due to pressure in the prone position combined with abduction and external rotation , leading to anterior shoulder dislocation Trauma , and elderly patients are at higher risk . Patients may also develop postoperative shoulder joint pain related to this intraoperative position .
It is vital to protect these vulnerable areas to help reduce the risk of developing pressure sores or nerve injuries during longer surgical procedures . And speaking of nerve , injuries this is definitely something that we want to avoid to help keep our patients safe during anesthesia care in the prone position .
Nerve ischemia may occur from excessive stretching or direct pressure leading to microvascular compression . Risk factors for nerve injuries include improper positioning of limbs , long cases , inadequate padding , anatomic variations , hypotension , anatomic variations , hypotension , diabetes , hypothermia , malnutrition .
Nerves that are at high risk in the prone position include the following the superior orbital nerves , lingual and buccal nerves , often strained due to unintentional jaw retraction caused by tension between master muscles .
The phrenic nerve and recurrent laryngeal nerve , potentially impacted by overextension or rotation of the neck , the brachial plexus , the ulnar nerve and the lateral cutaneous nerve of the thigh Next up . Let's review the physiologic changes that occur in the prone position . Go ahead and refresh your cup of coffee and grab a pen and paper . Here we go .
Let's start with changes that can impact the eyes . Patients in the prone position are at risk for ocular injuries due to direct or indirect pressure . Direct pressure on the eye may be due to improper positioning and this can cause ischemia .
In addition , prone positioning may lead to decreased venous outflow and increased intraocular pressure , with the resultant decreased intraocular perfusion .
Intraocular perfusion may be further compromised in the prone position by increased intra-abdominal pressure , decreased preload and decreased mean arterial blood pressure , putting patients at increased risk for optic nerve ischemia , ischemic optic neuropathy and central retinal artery occlusion .
Risk factors for postoperative visual loss following prone position include increased surgical duration , large blood loss and administration of large volumes of crystalloid IV fluid .
Patients with closed-angle glaucoma are at risk for blindness from prone positioning , even during short procedures if there is reduced aqueous humor outflow , leading to increased intraocular pressure , reduced blood flow and optic nerve injury .
Finally , it is important to remain vigilant for complete eye closure , since there is decreased tear production under general anesthesia and patients are at risk for corneal injury and irritation . We are going to stay at the patient's head and review head and neck changes in the prone position .
This position may increase intracranial pressure , combined with decreased cerebral blood flow , leading to intracranial vessel distension . You must remain vigilant , especially for patients with intracranial space-occupying lesions . Careful attention to neutral neck positioning is vital , since patients are at risk for vascular injury in the head , neck and chest .
Over-rotation of the neck may decrease carotid or vertebral artery blood flow and decrease venous drainage , while in the prone position , hydrostatic pressure increases , which may lead to dependent edema . This combination puts patients at risk for stroke , tongue swelling , tracheal compression and oropharyngeal and glottic edema .
You may notice that after repositioning from prone to supine , your patients developed facial , scleral and lingual edema . These patients may require a delayed extubation to allow time for the edema to resolve .
This is not the time to let down your guard , since patients who used to have a normal airway and were straightforward to intubate with a good view prior to prone positioning may become impossible to re-intubate or ventilate . Moving down the body , we made it to the lungs and the pulmonary system . So go ahead and take a deep breath .
There is some good news here , since pulmonary function may improve in the prone position due to the following Improvement in functional residual capacity , improved ventilation , perfusion matching and increased arterial oxygen tension . Chest wall and lung compliance are not affected in this position , but you may see increases in intrathoracic pressure and peak airway pressure .
There is a risk for increased pulmonary vascular resistance in the prone position . It is important to identify patients with obesity and sleep-related breathing disorders who may not tolerate prone positioning .
Consider obtaining a preoperative echocardiogram to evaluate systolic and diastolic function and identify patients with decreased heart function who may be at high risk for perioperative cardiac complications . And this brings us nicely to the next category cardiovascular system .
This review is sure to get your heart pumping , because we will be talking about changes in preload , afterload and contractility . The prone position can cause the cardiac index to decrease by 24% on average , and this is mostly from a decrease in stroke volume . Tachycardia and increased peripheral vascular resistance may also occur following repositioning prone .
In addition , patients with a history of heart failure , pulmonary hypertension or restrictive or obstructive lung disease who become acidotic may develop increased pulmonary vascular resistance and right ventricular strain , leading to significant hemodynamic instability . Constant vigilance is required . Hemodynamic instability Constant vigilance is required .
Here are some other changes in the cardiovascular system while patients are in the prone position Increased risk for mediastinal compression , with the right ventricle compressed against the sternum . Increased intrathoracic pressure , combined with decreases in IVC filling , atrial compliance and left ventricular compliance , leading to decreased cardiac output .
Local compression of the anterior chest wall or abdomen , leading to decreased right ventricular function or IVC preload . And we can't forget about the effects of volatile anesthetics and propofol on the cardiovascular system as well , since the combination can lead to hemodynamic instability .
These effects include decreased systemic vascular resistance , changes in heart rate and decreased cardiac contractility from myocardial suppression . Specially designed bolsters to provide support and padding for chest and abdominal positioning can help to minimize the physiologic changes .
Patients at higher risk from prone positioning include those with scoliosis , pectus excavatum or recent cardiothoracic surgery . Who is at risk for cardiovascular collapse in the prone position ? Risk factors include the following Massive blood loss , hypothermia , fluid shifts , cardiac comorbidities , venous air embolism , anatomic deformity such as thoracic lordosis or pectus excavatum .
The authors remind us that patients with right ventricular dysfunction , pulmonary hypertension , patients who are preload dependent and patients who are sensitive to increases in pulmonary vascular resistance are at risk for cardiovascular collapse in the prone position .
It may be necessary to have a conversation with the surgeon and patient to discuss the risks from prolonged prone positioning , which may include myocardial infarction and cardiac arrest , and determine how to proceed safely . Once again , we cannot let down our guard .
There are additional physiologic changes that occur in the prone position , especially in obese patients , due to abdominal compression , leading to decreased arterial inflow and venous outflow to the visceral organs . There are reports of postoperative pancreatitis and hepatic ischemia following surgery in the prone position .
Other complications from increased intra-abdominal venous compression include increased venous fleeting and increased risk for postoperative thrombotic complications . It is important to minimize direct pressure on the abdomen and specially designed bolsters or beds can help .
We also need to pay careful attention to the extremities in the prone position , especially for longer procedures and , depending on the patient's position , bending the hips and knees can decrease arterial blood flow and put patients at risk for limb compartment syndrome , rhabdomyolysis and the resultant renal failure .
The authors have highlighted quite a few threats to patient safety during anesthesia care in the prone position . We hope that you tune in next week because we are going to review some important clinical recommendations to help keep your patients safe .
In the meantime , we hope that you will check out episode number 16 of this podcast , all about postoperative vision loss from ischemic optic neuropathy , which is a complication following spine fusion surgery in the prone position . You can also check out the October 2020 APSF newsletter article Postoperative Vision Loss by Lori Lee .
I will include a link in the show notes as well . If you have any questions or comments from today's show , please email us at podcast at APSForg . Please keep in mind that the information in this show is provided for informational purposes only and does not constitute medical or legal advice .
We hope that you will visit APSForg for detailed information and check out the show notes to links to all the topics we discussed today . The APSF newsletter is the official journal of the Anesthesia Patient Safety Foundation . Readers include anesthesia professionals , perioperative providers , key industry representatives and risk managers .
It is free of charge and available in a digital format , with a focus on anesthesia-related perioperative patient safety issues . The June newsletter has just been published , but the deadline for the October 2024 APSF newsletter is right around the corner , on July 10th .
Check out the guide for authors over at APSForg for more information , and I will include a link in the show notes as well . Who knows , you could be the next APSF newsletter author and we might be featuring your article on a future anesthesia patient safety podcast . So what are you waiting for ? Go ahead and submit your article today .
Until next time , stay vigilant so that no one shall be harmed by anesthesia care .