Prospects for limb salvage after tourniquet placement has become a crucial matter for thousands of soldiers and their surgeons in the Ukraine war. Near-peer fighting conditions, and lack of air superiority, can create extended evacuation times for casualties. Drone threats to moving vehicles have become so pervasive that, in many areas, the last few miles up to the zero line area only traversable on foot. Beyond this zone, mud, bombing damage, UXOs, and the impossibility of road maintenance make vehicle evacuation slow and bumpy. Patients must often wait for nightfall to evacuate, and dawn-dusk day length at the height of summer on the Eastern Front is 17 hours. Today, almost two years into the war, high attrition rates amongst experienced frontline medics means loss of TCCC tourniquet conversion knowledge along the frontline.
For medics and doctors in forward casualty collection and stabilization points, who are receiving tourniqueted patients after prolonged evacuations from a near-peer conflict area, assessing patient candidacy for tourniquet conversion (i.e. removal and replacement with a simple pressure dressing) or movement of tourniquet to a more distal location is a critical outcome-changing skill. Just as important as assessing limb salvageability is 1) readiness to manage acute complications such as acidosis and dysrhythmias, and 2) ensuring that timely transfer to higher-level care is available for potential mediu-term complications, such as compartment syndrome and acute renal failure.
Current TCCC guidance assumes that limb salvage becomes highly unlikely 6 hours or more after tourniquet placement. However, this guidance is unavoidably based on the extremely limited data pool available to date. Limb salvage after tourniquet placement is a young and weak science, which stands to benefit greatly from case reporting and retrospective studies originating from the Ukrainian conflict. If we look only at the small pool of my personal experience as a paramedic in Ukraine, several case examples of physician-directed conversions of tourniquets in place for over 6 hours have been performed, or given post-conversion management, by either myself or my immediate colleagues. Clearly, amputating every limb that has been touniqueted for more than 6 hours would result in unnecessary negative life impacts for patients.
Current tourniquet science is based on animal studies done in controlled environments, and a very small number of human case reports. Tourniquets are widely used in routine surgeries, but tourniquet use in traumatic wartime injuries is a completely different animal. The reality of warfare adds in a number of important and unforeseen variables, which defy efforts to cleanly categorize patients as <6 hours vs >6 hours:
1) initial tourniquet placement is likely to occur under extreme conditions. Often, the soldier placing the tourniquet has minimal medical training, may be physically and/or mentally exhausted (many Ukrainian soldiers have been deployed for nearly 2 years with little or no leave), he or she may be receiving and returning fire, and may be working in conditions of darkness, loud noise, and confusion. The soldier placing the tourniquet may have reduced fine motor control due to cold, exhaustion, or adrenaline, or may be injured themselves. Weather and fighting conditions may have led to heat exhaustion, dehydration, nutritional deficits, soaked clothing, icy gear, numb fingers, or cold injuries of feet and hands, and rapid assessment and tourniquet placement and/or other bleeding control measures may have to be performed over/through multiple layers of clothing and body armor. Tourniquet availability on the frontlines is limited and likely to consist of a mish-mash of tourniquet brands and styles. These factors often conspire to create "partial-tourniqueted" patients. Tourniquets may be tightened enough to slow, but not fully stop, bleeding and limb perfusion. Venous and capillary return may be cut off, without halting arterial inflow.
2) Due to frontline conditions, time of original placement of tourniquets is frequently estimated, or missing altogether.
3) Environmental conditions and threats during evacuation may necessitate rapid movement and rough handling of the patient, which may lead to tourniquet loosening or temporary dislodgement. Poorly made or re-used tourniquets may stretch over time or fail, lead to placement of multiple tourniquets, and intermittent periods of reperfusion or partial reperfusion.
4) Intentional attempts at tourniquet conversion may be made in the field. Due to fighting conditions, these field attempts may or may not be accurately recorded in the documentation that reaches field hospitals. Patients evacuation routes shift frequently, and patients may pass through multiple patient care teams, comprised of a shifting cast of medical providers.
5) The tourniqueted limb may be subjected to a variety of physiological and environmental conditions, including varying levels of external cooling, varying states of patient blood loss and shock, and varying levels of resuscitative care received.
Due to these variables, Ukrainian doctors cannot rely on hard-and-fast rules such as the 6-hour tourniquet rule. Many tourniquets were placed with good intent, but were never necessary in the first place. Doctors are often forced to decide, based on clinical observations and professional experience, whether tourniquet removal is in the patient's best interest. Does the probability of limb salvage outweigh potential systemic risks to patients? Objective numerical values from blood testing can inform these decisions, if lab services are available. But more often, the critical time for this decision occurs at minimally-equipped forward field treatment points, and thus it must be made based on time of injury, exposure to weather, limb skin color and temperature, injury patterns, and overall patient presentation.
Here is an interesting case report from Kragh et al, published in Orthopedic Trauma in 2007, which represents the realities of tourniquet placement in conflicts, as well as variability in limb salvage times. The patient, an American helicopter pilot in Afghanistan, was shot in the hand and received RPG shrapnel to one leg. Hemorrhage from the hand was stopped 1 hour after injury by a combination of one purpose-built and one improvised tourniquet. Bleeding recurred 6 hours after injury, and was stopped by tightening the tourniquet. The pilot lay in a snowdrift, with temperatures at -15C, for a half-day after injury. After that, he was insulated by blankets made from cut-out aircraft insulation. Evacuation was delayed due to an ongoing firefight, mountainous terrain, and inclement weather. The patient arrived at a forward surgical facility after 16 hours of continuous tourniquet placement. He had severe soft tissue loss, irreparable radial artery damage, and compartment syndrome. He underwent surgical debridement and irrigation, radial artery ligation, and 3 dorsal + 2 ventral hand fasciotomies, and the operating surgeon deemed hand preservation was questionable. Repeated surgical debridement and irrigation took place over the next month, first at Landstuhl, Germany, then at Walter Reed, before primary wound closure was accomplished. Several more surgeries and physical therapy followed, to correct pain and stiffness. By three years after injury, the patient had recovered sufficiently to use the hand for activities of daily living, and to return to piloting Chinook helicopters.
No comments:
Post a Comment