Page 192 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 14 · Surgery of the lung

Problem Causes Solutions
Hypothermia
• Slow warming using water blankets or forced hot air warmers
Prolonged surgical time; open
VetBooks.ir thorax; loss of
thermoregulation due to
anaesthesia
Fluid loss
Hypovolaemic shock
Pain • Intravenous fluid support monitor urine output
• Provide supplemental analgesia (note: opiates are respiratory depressants)
Hypothermia • Slow warming using water blankets or forced hot air warmers
Acid–base disturbances (lactic • Fluid and colloid support to ensure good oxygen delivery to the tissues
acidosis from poor tissue
perfusion)
Hypoventilation Anaesthetic protocols • artial reversal of opiate medication if used using butorphanol tartrate at . mg/kg
(blood pCO 2
mmHg) Pain • Provide supplemental analgesia (note: opiates are respiratory depressants) and local
anaesthesia with intercostal blocks at surgery and interpleural bupivacaine
postoperatively
Pneumothorax • Address pneumothorax
• rovide o ygen therapy maintain blood haemoglobin saturation 3
pO mm g
Thoracic bandage • Loosen restrictive bandage
Hypoxaemia Atelectasis • rovide o ygen therapy maintain blood haemoglobin saturation 3
pO mm g
Pleural space disease • Aspirate thoracostomy tube and alternate recumbency of patient
Pain Thoracic surgery; underlying • Intercostal nerve blocks 1. mg/kg total dose bupivacaine infiltrating the nerves at
disease the thoracotomy and two rib spaces cranial and caudal to this incision
• Interpleural bupivacaine 1. mg/kg total dose infused via thoracostomy tube
incision-dependent repeat h as needed
• egional anaesthesia ith preservative-free morphine at .1 mg/kg given as high
epidural or via epidural catheter
• ystemic analgesics e.g. morphine o ymorphone hydromorphone . lo infusion of
lidocaine into surgical ound using soaker/diffusion catheter at a rate of 1 mg/kg/h
14.4 Postoperative problems in the thoracic surgery patient.

bandages or pneumothorax. Hypoventilation is confirmed pressure, and qualitative and quantitative assessment of
by an arterial blood pCO 2 mmHg. If hypoventilation is thoracic drainage (Guillaumin and Adin, 2015).
suspected secondary to anaesthetic medications, a partial Perioperative pain management is essential in the
opiate reversal agent such as butorphanol tartrate can be recovery of the thoracotomy patient. Intercostal nerve
used and benzodiazepines can be reversed with flumazenil. blocks may be performed intraoperatively with bupi-
Hypoventilation secondary to pain should be addressed by vacaine or ropivacaine at 1.5 mg/kg total dose, infiltrating
providing supplemental analgesia, but caution should be the nerves of the intercostal incision and two rib spaces
used as many opiates are respiratory depressants at high cranial and caudal to the incision. Long-acting liposome-
doses. If a thoracic drain is in place it should be aspirated encapsulated bupivacaine at a dose of 5.3 mg/kg can also
to rule out or address pneumothorax or accumulation of be infiltrated into the tissues during closure. Regional
pleural effusion. Oxygen therapy should be provided during anaesthesia and pain control with either a high epidural
initial recovery as many patients are hypoxaemic second- (single injection) or an epidural catheter for repeated injec-
ary to the primary disease, acidosis or atelectasis. tions can also be very useful. Preservative-free morphine
Oxygenation can be monitored with pulse oximetry and is used at a dose of 0.1 mg/kg and may be administered
arterial blood gas analysis. The goal of the therapy is to every 1 4 hours via the epidural catheter. Alternatively,
maintain blood haemoglobin saturation 9 93 or pO 2 bupivacaine can be administered interpleurally (1.5 mg/kg
>80 mmHg, respectively. total dose) via the thoracostomy tube. The patient should
In general, the patient will have had a thoracostomy be placed in sternal or lateral recumbency with the incision
tube placed intraoperatively for use in postoperative down to deliver medication effectively to the surgical site.
management (see also Chapter 12, or the BSAVA Guide to This method of local analgesia is useful for supplemental
Procedures in Small Animal Practice). The thoracostomy analgesia after surgery, as it can be repeated every 6 8
tube is essential to monitor and manage complications hours as needed. Another option is the use of wound/diffu-
such as pneumothorax or haemothorax. The thora- sion catheters (MILA International, Inc.), which are polyure-
costomy tube should be aspirated every 6 hours until thane catheters with micropores in the distal end. They
the fluid or air production is ml kg day, at which time can be placed in the thoracotomy incision at the time of
the tube may be removed. All connections should be closure, like a drain, but infused with local anaesthetic (2
secure and the tube should be handled aseptically to mg/kg lidocaine and 1.5 mg/kg bupivacaine) (see BSAVA
prevent iatrogenic pneumothorax and nosocomial infec- Manual of Canine and Feline Anaesthesia and Analgesia).
tions. The tube should be covered with a light bandage to Systemic analgesia, in the form of opiates such as
protect it, but care should be exercised so that the band- morphine, oxymorphone or hydromorphone, can be used
age does not interfere with ventilation. Possible postop- as necessary. It is generally safer to start with the lower
erative haemorrhage should be monitored by periodic doses and repeat dosing to titrate analgesia while trying to
assessment of packed cell volume/total protein and blood avoid excess respiratory depression.

183

Ch14 HNT.indd 183 31/08/2018 13:20