Abstract

Objectives. The ongoing conflict in Afghanistan continues to generate a large number of complex trauma injuries and provides unique challenges to military anesthetists working in forward field hospitals. We report successful use of ultrasound-guided continuous transversus abdominis plane (TAP) block in two Afghan war casualties who sustained major trauma with coagulopathy. The use of bilateral continuous TAP blocks following major thoracoabdominal trauma in a combat environment is unique in the literature.

Design. Case report.

Results. The acute perioperative outcomes of two Afghan civilian patients were improved with bilateral continuous TAP blocks. Multiple benefits shared by both patients included early extubation, excellent analgesia, and minimal post-operative morphine requirements despite the setting of a massive blood transfusion and coagulopathy.

Conclusions. A continuous TAP block technique can be utilized to provide excellent analgesia following major abdominal surgery when neuraxial anesthesia is contraindicated. The TAP block's ease of placement under ultrasound guidance makes this technique particularly useful in the austere battlefield hospital environment.

Introduction

The ongoing conflict in Afghanistan continues to generate a large number of complex multi-trauma patients. This provides a unique challenge to military anesthetists working in forward field hospitals. These hospitals are primarily in place to treat coalition forces' injuries as well as civilian casualties.

Regional anesthesia techniques have been introduced in combat theater to assist with acute pain management and aeromedical evacuation of coalition forces [1]. Our experiences have demonstrated that these techniques assist with early extubation, encourage rapid mobilization, and serve as a viable alternative to an opioid based approach in a local population where manufacturing poppy and opium is a significant contribution to Afghanistan's economy.

We report the successful use of ultrasound-guided continuous TAP block in two Afghan civilian war casualties who had sustained major thoracoabdominal injuries and developed significant coagulopathies. This case report demonstrates the utility of ultrasound-guided continuous TAP block in managing acute postoperative pain when multimodal pain therapy is limited.

Case Presentation

Case Report #1

A 20-year-old (American Society of Anesthesiologist physical status 3E) Afghan civilian male sustained multiple blast and fragmentation injuries from an individual wearing a suicide vest packed with ball bearing explosives. He was rapidly evacuated by helicopter to a coalition field hospital. Initial examination revealed multiple chest and abdominal injuries which included bilateral pneumothoraces, gastric and bowel injuries as well as an extensive liver fracture, which was due to multiple metal projectiles from the blast.

A damage control exploratory laparotomy was performed upon arrival, which included repair of his right iliac vein, perihepatic packing, segmental resection of the bowel, and bilateral placement of thoracostomy tubes. His resuscitation included 10 units of packed red blood cells (PRBCs), 4 units of fresh frozen plasma (FFP), and 1 unit of cryoprecipitate. After the surgery, he remained intubated and was transferred to the intensive care unit (ICU) where his temperature and coagulopathy could be further managed.

On post-operative day (POD) two, he returned to the operating room for a laparotomy, small bowel anastamosis, and abdominal wound closure. During his perioperative course, the patient manifested a mild coagulopathy (Prothrombin time [PT] 24.9 seconds [s], Activated partial thromboplastin time [aPTT] of 33.7 s, hemoglobin 9.8 g/dL, platelets 107,000/mm3).

Case Report #2

A 25-year-old (American Society of Anesthesiologist physical status IIIE) Afghan civilian male sustained a gunshot wound to the abdomen and was transferred by helicopter to a coalition field hospital. Initial examination revealed multiple abdominal injuries to include a bowel and gallbladder injury, as well as a grade IV liver injury.

A damage control exploratory laparotomy was performed on arrival, which included hepatic packing, segmental resection of the bowel as well as a cholecystectomy. His resuscitation included 8 units of PRBCs, 10 units of FFP, 1 unit of cryoprecipitate, and 2 units of platelets. After surgery, he remained intubated and was transferred to the ICU for a 48-hour period.

On POD two, he returned to the operating room for a laparotomy, small bowel anastamosis and abdominal wound closure. Perioperatively, his laboratory values (PT 22.1 s, aPTT 33.6 s, hemoglobin 9.6 g/dL, platelets 109,000/mm3) demonstrated a dilutional coagulopathy in addition to his anemic state.

Post-operative Pain Management

Upon completion of both patients' procedures, the surgeon consulted with the acute pain service to discuss postoperative analgesic options. Maintenance of ICU bed space is a constant issue within a field hospital that is subject to frequent war casualties. The acute pain service provides a unique opportunity to facilitate patient transfers as patients with acceptable pain control will be earlier candidates for evacuation. Effective analgesia following thoracoabdominal trauma permits early weaning from mechanical ventilation which ultimately results in earlier extubation and patient transfer.

Although there are numerous studies that have documented the safety of epidural anesthesia and analgesia in the anticoagulated patient, epidural anesthesia options were limited in these two cases due to massive blood transfusion and subsequent coagulopathy. With concerns for epidural hematoma and catastrophic neurologic dysfunction, the decision to withhold neuraxial anesthesia was based on the findings of the American Society of Regional Anesthesia and Pain Medicine Second Consensus Conference on Neuraxial Anesthesia and Antiocoagulation [2]. As an alternative to neuraxial anesthesia, a bilateral ultrasound-guided continuous transversus abdominis plane (TAP) block was selected for both patients in an attempt to improve abdominal wall analgesia and respiratory mechanics.

Technique

Prior to the initation of the TAP block, both patients were intubated and anesthetized with a general anesthetic technique consisting of oxygen, air and Sevoflurane. Using the SonoSite MicroMaxx® (SonoSite Inc., Bothell, WA) with a HFL38 high frequency probe (13–6 MHz), we identified the TAP under direct visualization. After hydrodissection of the tissue planes, we then placed bilateral continuous catheters via an 18-gauge Contiplex Tuohy needle system (B. Braun Medical Inc., Bethlehem, PA) using the technique described by Carney et al. [3] (Figure 1).

Figure 1

Ultrasound visualization of TAP anatomy. PP = parietal peritoneum; TAF = transversus abdominis fascia; IOF = internal oblique fascia; EOF = external oblique fascia.

Figure 1

Ultrasound visualization of TAP anatomy. PP = parietal peritoneum; TAF = transversus abdominis fascia; IOF = internal oblique fascia; EOF = external oblique fascia.

To facilitate catheter insertion, both patients' blocks were bolused with 20 mL of 0.5% bupivacaine with epinephrine 1:400,000. Each catheter was secured with Dermabond® (Ethicon Inc., Somerville, NJ), Steri-Strips™ (3M, St. Paul, MN) and a transparent dressing (Tegaderm™, 3M, St. Paul, MN). Two separate infusion pumps (Braun Compact Infuser, Melsungen Germany) were programmed to infuse 0.125% bupivacaine at 8 mL/h and were subsequently connected to each catheter. The patients were then transferred to the ICU where they were both uneventfully extubated within 6 hours. The critical care team considered the analgesia provided by the blocks as a decisive factor in the successful extubation of these two patients. The acute pain service (accompanied by a Pashto language interpreter) reviewed both patients' pain scores at 6, 12, and 24 hours post-operatively.

Over a 24-hour period, Patient A received 4 mg of morphine in addition to his regular doses of paracetamol (1 g every 6 hours) The patient's pain was assessed using a verbal numeric 0–3 rating scale that corresponded to: 0 = no pain, 1 = minimal pain, 2 = moderate pain, and 3 = severe pain. Patient A reported his pain as “minimal” on each occasion. The patient's vital signs remained stable during his hospitalization and he was evacuated to a civilian hospital within 48 hours. Prior to his transfer, the two catheters were removed.

Patient B received 2 mg of morphine in addition to his regular doses of paracetamol (1 g every 6 hours) over the 24-hour period. Similar to patient A, patient B's pain was assessed using the verbal numeric 0–3 rating scale. Patient B reported his pain as “minimal” on each occasion which prompted his transfer to a civilian hospital within 24 hours of his hospitalization. Similar to Patient A, his catheters were also removed prior to his evacuation.

Discussion

The use of the continuous TAP block described in this case report provided multiple benefits to the two civilian trauma patients (Table 1). Multiple perioperative benefits of the TAP block include excellent analgesia, rapid extubation, early hospital discharge, as well as an alternative technique to central neuraxial anesthesia when a coagulopathy is present.

Table 1

Perioperative benefits of TAP block

• Excellent analgesia 
• Rapid extubation 
• Timely transfer to civilian facilities 
  • Promotes early patient-family interaction 
  • Reduces strain on limited military resources in austere combat environment 
• Avoidance of central neuraxial blockade in a patient with established coagulopathy (trauma) 
• Alternative to opioid-based therapy in patients with a known tolerance to opioids due to prior abuse and culture 
• Excellent analgesia 
• Rapid extubation 
• Timely transfer to civilian facilities 
  • Promotes early patient-family interaction 
  • Reduces strain on limited military resources in austere combat environment 
• Avoidance of central neuraxial blockade in a patient with established coagulopathy (trauma) 
• Alternative to opioid-based therapy in patients with a known tolerance to opioids due to prior abuse and culture 

The TAP block has been described as opioid sparing for multiple surgeries including cesarean delivery, open retropubic prostatectomy, and large bowel resections [4–6]. Although the ultrasound guided TAP block has been described before for major abdominal surgery [3], the use of continuous bilateral TAP catheters in the setting of combat multisystem trauma and coagulopathy is unique.

Paracetamol is an intravenous formulation of acetaminophen known as Perfalgan® (Bristol-Myers Squibb Pharmaceuticals Ltd, Middlesex, United Kingdom) which was launched in the United Kingdom in 2004 as a treatment for acute pain and fever. The recommended dose for adults weighing more than 50 kg is 1 g every 6 hours as needed with a maximum dose not to exceed 4 g per day. Contraindications to paracetamol include allergies or hypersensitivities to paracetamol and severe liver disease. Although both patients presented with penetrating abdominal injuries to include liver injury, a dilutional coagulopathy was most likely related to massive blood transfusion. Without evidence of diffuse parenchymal liver failure, the acute pain service and surgeon both felt sufficient liver metabolic reserve was present to justify a short course of intravenous paracetamol in order to facilitate early pain relief, which subsequently permitted a ventilator to be available for the next trauma patient.

While this case report only describes our experience with two patients, continuous bilateral TAP blocks represent a unique alternative in patients who have contraindications to neuraxial anesthesia.

Due to the need for rapid transfer of patients, we recognize the main limitation of this report as the short time period available to evaluate the effectiveness of the continuous TAP blocks. Since these patients were sent to a civilian hospital within 48 hours of their injury, we were unable to obtain any follow-up information.

Risks associated with the TAP nerve block technique should always be considered prior to performing the procedure. These risks include block failure, catheter-related infection, inadvertent intravascular local anesthetic injection, and bowel perforation. Farooq and Carey describe a case report of liver trauma with a blunt needle while performing the TAP block [7]. In an attempt to minimize these risks, ultrasound-guided placement of bilateral catheters by a skilled operator is essential.

Conclusions

Pain management of major trauma casualties in a combat environment provides a unique set of challenges to an acute pain management service. This case report demonstrates that a continuous TAP block technique can be utilized to provide excellent analgesia following major abdominal surgery when neuraxial analgesia is contraindicated. The TAP block's ease of placement under ultrasound guidance makes this technique particularly useful in the austere battlefield hospital environment. Future studies should be directed at comparing epidural analgesia and TAP continuous peripheral nerve block in abdominal surgery patients.

References

1
Buckenmaier
CC
McKnight
GM
Winkley
JV
et al
Continuous peripheral nerve block for battlefield anesthesia and evacuation
.
Reg Anesth Pain Med
 
2005
;
30
:
202
5
.
2
Horlocker
TT
Wedel
DJ
Benzon
H
et al
Regional anesthesia in the anticoagulated patient: Defining the risks (the Second ASRA Consensus Conference on neuraxial anesthesia and anticoagulation)
.
Reg Anesth Pain Med
 
2003
;
28
:
172
97
.
3
Carney
JJ
McDonnell
JG
Bhinder
R
Maharaj
CH
Laffey
JG
.
Ultrasound guided continuous transversus abdominis plane block for post-operative pain relief in abdominal surgery
.
Reg Anesth Pain Med
 
2007
;
32
(
suppl 1
):
24
.
4
McDonnell
JG
Curley
G
Carney
J
et al
The analgesic efficacy of transversus abdominis plane block after cesarean delivery: A randomized controlled trial
.
Anesth Analg
 
2008
;
106
:
186
91
.
5
O'Donnell
BD
.
The Transversus Abdominis Plane (TAP) block in open retropubic prostatectomy
.
Reg Anesth Pain Med
 
2006
;
31
:
91
.
6
McDonnell
JG
O'Donnell
B
Curley
G
Heffernan
A
Power
C
Laffey
JG
.
The analgesic efficacy of transversus abdominis plane block after abdominal surgery: A prospective randomized controlled trial
.
Anesth Analg
 
2007
;
104
:
193
7
.
7
Farooq
M
Carey
M
.
A case of liver trauma with a blunt regional anesthesia needle while performing transversus abdominis plane block
.
Reg Anesth Pain Med
 
2008
;
33
:
274
5
.
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Disclaimer: The views expressed in this presentation are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, the U.K. Ministry of Defence or the U.S. & U.K. Governments.