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Quid novi in the eldery patient’s anesthesia

BMC Geriatrics201111(Suppl 1):A26

https://doi.org/10.1186/1471-2318-11-S1-A26

Published: 24 August 2011

Background

Today the availability of new local anesthetics and the use of analgesics, allow the modulation of the analgesia, maintaining a state of consciousness.

An answer to the needs of patients >75 years undergoing surgery is the technique Monitored Anesthesia Care (MAC), defined “the middle land” (Figure 1).
Figure 1

Monitored anestesia care

MAC allows:
  • the modulation of the level of analgesia at different stages of surgery due to the availability of analgesic action, but with rapid onset-time

  • the additional analgesia using local anesthetics with prolonged effect without the use of noradrenaline, dangerous for elderly patients

the consciousness and cooperation of the patient (Table 1).
Table 1

MAC.

Conscious Sedation (MAC)

Unconscious Sedation

Altered consciousness

Unconsciousness

Conscious patient

Unconscious patient

Protective reflexes intact and active

Protective reflexes decreased; airway obstruction may occur

Ventilation: hypoxia, hypercapnia

Cardiovascular system: , hypotension, hypertension, bradycardia, tachycardia

Stable vital signs

Unstable vital signs

Analgesia may be present; need for regional analgesia / local or systemic

Pain controlled centrally; does not require regional analgesia

Limited stay in the units of observation

Requiring hospitalization or prolonged hospitalization

Low risk of complications

High risk of complications

Infrequent postoperative complications

Frequent postoperative complications

Patients with psychiatric problems or mental deficiency may be difficult to manage

May be needed to manage patients with mental deficiency

Materials and methods

With this study we tested the efficacy, safety and limitations of the MAC.

The design of the study was a prospective, double-blind, parallel-group, with 42 patients randomly selected from 87 patients recruited between those eligible for inclusion in the circuit one-day surgery (Table 2)
Table 2

Patients’ criteria of homogeneity.

Patients’ criteria of homogeneity

same level of gravity ASA II/III

NYHA II class

same duration of surgery (40 min ± 10 min

Two groups were subjected to two different regimes of sedation with propofol and midazolam, pain controlled with remifentanil.
  • Primary end-point was verifying the level and quality of sedation achieved

  • Secondary end-point was identifying and quantifying potential adverse effects (Table 3-4)

Table 3

Access Criteria.

ACCESS CRITERIA

Weight 69 ± 6 Kg

Informed consent for MAC procedures

ASA II/III with stabilized cardio-circulatory impairments and respiratory parameters: pO2 ≤ 70 e pCO2 < 45 mmHg

Patients undergoing operations can be managed only with the cooperation of the patient

Age > 75 years

Table 4

Exclusion Criteria.

EXCLUSION CRITERIA

Patient desire

ASA III impairment of vital organs in acute and evolutionary phase

Patients with unexpected rapid intubation

Patients with high risk of bleeding

Severe neurological disorders

Levels of sedation, pain and mental status were assessed using different clinical approaches :
  • Observational data (Table 5).

Table 5

Observer’ s assessment of alertness/sedation scale (oaa/s scale).

Answer

Verbal expression

Facial expression

Eyes

 

Ready to the call, normal tone

Normal

Normal

Normal

5

Torpid to the call, normal tone

Initial slowdown

Medium relaxation

Medium relaxation

4

Only for repeat calls with high tone

slowdown

Marked relaxation

Marked ptosis

3

Only if shaken

Not understandable words

---

---

2

No answers, even if shaken

---

---

---

1

We proceeded as follows:
  1. 1)

    O2 inhalation (SpO2 > 98 and normocapnia)

     
  2. 2)

    during surgical manipulation a continuous infusion of remifentanil: 0.03 to 0.06 mg / kg / h was activated

     
Patients were randomly dichotomized into two arms with two different infusion regimens:
  • group P (45 patients): starter bolus of 0.5 mg / kg propofol (to fill the central compartment) → P infusion of 1-2 mg / kg / h (to offset the rapid deployment)

  • group M (41 patients): bolus starter from 0.03 to 0.05 mg / kg midazolam (average dose of 2-4 mg) infusion of 1-2 mg / kg / h

Every 10 m’ scores are recorded, BIS and OAA / S scale.
  • objective parameters based on Ramsay Scale (Table 6).

Table 6

Ramsay Scale.

1

Patient anxious and agitated or restless, or both

2

Patient co-operative, orientated and tranquil

3

Patient responds to commands only

4

Brisk response to a light glabellar tap or auditory stimulus

5

Sluggish response to a light glabellar tap or auditory stimulus

6

No response to the stimuli mentioned in items 4 and 5

  • Instrumental response with Bispectral Index (Table 789)

Table 7

Average values of clinical and instrumental group P.

 

T10m

T20m

T30m

T40m

BIS

72 (42-45)

66 (35-88)

70 (55-82)

74 (52-88)

OAA/S

4 (1-5)

3-4 (1-5)

3-4(1-5)

4 (1-5)

Table 8

Average values of clinical and instrumental group M.

 

T10m

T20m

T30m

T40m

BIS

64 (48-86)

58 (35-73)

62 (36-84)

66 (48-83)

OAA/S

4 (1-5)

3-4 (1-5)

3-4 (1-5)

4 (1-5)

Table 9

Propofol, Midazolam, Remifentanil during MAC.

 

Propofol

Midazolam

Remifentanil

onset of sedation

rapid

moderate

rapid

resolution pharmacological effects

rapid

lenta

rapid

injection pain

yes

no

no

intraoperative and postoperative pain

moderate

moderate

minimum

hemodynamic depression

moderate

minimum

minimum

respiratory variations

mild desaturation (<30%)

minimum

moderate

PONV

minimum

minimum

minimum

Conclusions

The combination midazolam-remifentanil presented a lower synergistic effect compared with propofol-remifentanil. The first fact documented a mean BIS of 62.5 +3 vs. 64.7 +4 midazolam-remifentanil association and has finally, although sporadic, incidents of desaturation content and never > 30%. The evaluation of the kinetic values of BIS, the interesting fact that emerges concerns the values> 70, which represented a significant predictor in the study to better recovery of consciousness, which has helped the fast-traking ongoing day-surgery.

Authors’ Affiliations

(1)
Department of Anaesthesia, Surgical and Emergency Science, Second University of Naples

References

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Copyright

© Lettieri et al; licensee BioMed Central Ltd. 2011

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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