Abstract
Nine harbor seals (age 21–34 years; X = 26; 7 females, 2 males) were anesthetized for bilateral lensectomy. Seven of the seals had preoperative bloodwork and electrocardiography (ECG) performed within one month of surgery. Three seals also had echocardiography performed, in addition to blood and ECG, prior to surgery. Three patients had no preoperative workup. All seals were clinically healthy at the time of surgery.
The seals were premedicated with midazolam (0.2–0.25 mg/kg IM) and atropine (0.02 mg/kg IM), followed by anesthetic induction with propofol, injected into the epidural sinus, to effect, for intubation. Anesthesia was maintained with isoflurane in rebreathing circuits. Anesthetic duration ranged from four to five hours. All seals had epidural-type catheters placed in the epidural sinus and received dobutamine (0.5–1 µg/kg/min IV) and crystalloidal fluids (lactated ringers solution or sodium chloride, 2–4 ml/kg/hour IV) continuously once catheterized. All seals received lactated ringer's solution (1–1.5 liters SC) near the end of surgery. Seven seals received a single dose of furosemide (0.5 mg/kg IM or SC) prior to recovery. All patients also received flumazenil (0.005–0.01 mg/kg IM, IV or both) in recovery. Atracurium, a non-depolarizing neuromuscular blocking agent, was used to attain proper position of the globe. Intermittent positive pressure ventilation was performed via mechanical ventilator or by hand (rebreathing bag) when paralyzed, at a rate of three to six breaths per minute, with a maximum inspiratory pressure of twenty to thirty centimeters of water. Most seals became cold during the procedure, and body temperature was maintained with various heating devices (circulating warm water or air, heating pads, blankets). Body temperature was monitored with probe-style thermometers placed in the rectum or esophagus (or both). Heart rate was monitored via electrocardiography, pulse oximetry, and auscultation. Oxygen saturation was measured using pulse oximeter devices with probes placed in the oral cavity, anus, vulva, or prepuce. End-tidal carbon dioxide was measured with various units incorporated into the airway circuit. Direct or indirect blood pressure was not measured. Periodic blood samples were collected for blood gas and other parameters utilizing i-STAT analyzers. Full blood profiles were performed on-site when possible. Venous samples were collected from the epidural sinus. Arterial samples were collected from the ventral coccygeal artery. Table 1 summarizes the data collected from the seals.
All seals survived. The anesthetic protocol appears to be safe for geriatric harbor seals. The data collected may help with future cases.
Table 1.
|
Sex
|
Age
(yrs)
|
Wt
(kg)
|
Premed
Midazolam = M
Atropine = A
|
Induction
agent
(total)
|
Gas
|
Reversal
agents
Flum =
Flumazenil
|
Time to
extubation
after gas
off
|
Duration
premed
to extub
|
Temp
range (F)
|
Heart
rate
range
(ave)
|
|
M
|
26
|
80
|
M 20 mg im
A 1.6 mg im
|
Propofol iv
(200 mg)
|
Iso
|
Flum
0.2 mg
im and iv
|
40 mins
|
4.5 hrs
|
91.4–92.3
|
81–105 (90)
|
|
F
|
29
|
66
|
M 15 mg im
A 1.6 mg im
|
Propofol iv
(150 mg)
|
Iso
|
Flum
0.3 mg
im and iv
|
45 mins
|
5 hrs
|
91.7–94
|
55–75 (70)
|
|
F
|
24
|
60
|
M 15 mg im
A 1.3 mg im
|
Propofol iv
(100 mg)
|
Iso
|
Flum
0.3 mg im
|
30 mins
|
4.5 hrs
|
93.1–94.3
|
78–100 (85)
|
|
F
|
26
|
61
|
M 15 mg im
A 1.3 mg im
|
Propofol iv
(120 mg)
|
Iso
|
Flum
0.3 mg im
|
35 mins
|
5 hrs
|
89.6–93.2
|
65–88 (75)
|
|
F
|
23
|
71
|
M 17.5 mg im
A 1.6 mg im
|
Propofol iv
(150 mg)
|
Iso
|
Flum
0.35 mg im
|
17 mins
|
4 hrs
|
91.6–92.3
|
80–100 (90)
|
|
F
|
35
|
87
|
M 17.5 mg im
A 1.6 mg im
|
Propofol iv
(180 mg)
|
Iso
|
Flum
0.2 mg im and iv
|
40 mins
|
4 hrs
|
91.7–93
|
70–85 (75)
|
|
F
|
27
|
68
|
M 17 mg im
A 1.4 mg im
|
Propofol iv
(150 mg)
|
Iso
|
Flum
0.3 mg im
|
13 mins
|
5 hrs
|
91.9–94.6
|
65–98 (85)
|
|
M
|
27
|
85
|
M 20 mg im
A 1.7 mg im
|
Propofol iv
(300 mg)
|
Iso
|
Flum
0.4 mg im
|
45 mins
|
4.5 hrs
|
89.5–91.0
|
72–85 (80)
|
|
F
|
21
|
79
|
M 16 mg im
A 1.6 mg im
|
Propofol iv
(200 mg)
|
Iso
|
Flum
0.3 mg im
|
26 mins
|
4 hrs
|
91.5–93.6
|
70–91 (85)
|
Table 1, cont.
|
Sex
|
Age
(yrs)
|
Wt
(kg)
|
Premed
Midazolam = M
Atropine = A
|
ETCO2 range
(ave)
|
Pulseox SpO2 range
(ave)
|
pH (A)
|
pH (V)
|
PO2 (A)
|
PO2 (V)
|
PCO2 (A)
|
PCO2 (V)
|
Lactate
|
iCal
|
|
M
|
26
|
80
|
M 20 mg im
A 1.6 mg im
|
24–32
(29)
|
100
|
7.30
7.31
|
7.40
|
371
451
|
85
|
61
55
|
43
|
|
|
|
F
|
29
|
66
|
M 15 mg im
A 1.6 mg im
|
31–36
(34)
|
81–99
(92)
|
|
7.37
7.38
7.36
7.36
|
|
82
86
105
122
|
|
50
47
46
47
|
2.92
2.48
|
0.95
1.07
|
|
F
|
24
|
60
|
M 15 mg
im
A 1.3 mg im
|
36–72
(44)
|
82–97
89)
|
7.12
7.24
|
|
231
304
|
|
109
62
|
|
|
1.16
|
|
F
|
26
|
61
|
M 15 mg im
A 1.3 mg im
|
34–43
(38)
|
94–98
(96)
|
7.21
7.22
|
7.30
|
302
341
|
38
|
69
62
|
54
|
|
1.10
0.98
0.75
|
|
F
|
23
|
71
|
M 17.5 mg im
A 1.6 mg im
|
36–61
(46)
|
85–100
(95)
|
7.36
7.23
|
7.35
|
592
337
|
40
|
55
67
|
50
|
|
1.07
1.09
0.77
|
|
F
|
35
|
87
|
M 17.5 mg im
A 1.6 mg im
|
41–46
(43)
|
97–100
(99)
|
|
|
|
|
|
|
|
|
|
F
|
27
|
68
|
M 17 mg im
A 1.4 mg im
|
42–53
(46)
|
97–98
(98)
|
|
7.19
7.23
|
|
67
74
|
|
83
78
|
|
1.16
1.15
|
|
M
|
27
|
85
|
M 20 mg im
A 1.7 mg im
|
42–50
(44)
|
95–98
(97)
|
|
7.26
|
|
155
|
|
65
|
|
|
|
F
|
21
|
79
|
M 16 mg im
A 1.6 mg im
|
37–54
(45)
|
|
|
|
|
|
|
|
|
|