spinal anesthesia for ambulatory surgery

Spinal Anesthesia for Ambulatory Surgery

SubTitles :• Ambulatory Surgeries:

- Overview.

- Criteria of Selection.• Anesthesia Management:

- Pre-operative Assessment.- Intra-operative (Spinal).- Post-operative care.

Overview on Ambulatory Surgeries

• History: – Historians dispute whether Crawford Long, in 1842, or

William Morton, in1846, first used Ether for anesthesia in the United States. But what these two pioneers had in common was that their patients were outpatients.

– After that time and for more than 100 years, hospitalization of patients both before and after operation was the norm.

Overview on Ambulatory Surgeries

• History:- Over the past 4 decades, ambulatory surgery has grown

from less than 10% to over 70% of all elective surgical procedures.

Rationale for Ambulatory Surgery

Facility Design

Essential Components of Ambulatory Surgery Facility:

Facility Design

1. Hospital Integrated. (shared with inpatients)

2. Hospital-based. (Facility within a hospital handles only out patients)

3. Freestanding. (separated buildings for outpatients associated to a hospital or medical center)

4. Office-based. (usually are private diagnostic and operative suites managed by conjunction of physicians and health care providers for patients convenience)

Role of Anesthesiologist In Ambulatory Surgery

Patient Selection Criteria

• Selection of procedure.• Duration of surgery.• Patient characteristics ( ASA, Age, MH

susceptibility ).• Contraindications.

Selection of Procedure• Suitable procedures for ambulatory Surgery:

Selection of Procedure

• Non-Suitable procedures for ambulatory Surgery:

- Procedures associated with major postoperative complications, i.e. bleeding or major fluid shifts (e.g. extensive plastic surgery, reduction mammoplasty, liposuction).

- Procedures requiring prolonged immobilization and parenteral opioid analgesic therapy.

Duration of Surgery

• Was originally limited to procedures lasting less than 90 minutes.

• Now, 3 – 4 hours surgeries are routinely performed on an ambulatory basis.

Patient Characteristics• Originally, ASA I and II patient are only eligible for ambulatory surgery.• Now, with improvement in Anesthesia and surgical care ASA III and

even some ASA IV in whom medical condition is stable are eligible for ambulatory surgery.

• Therefore, the ASA physical status should not be considered in isolation because the type of surgical procedure, the anesthetic technique, and a multitude of medical and social factors can also influence decisions regarding a patient's suitability for ambulatory surgery.

Evidence Base:In a large, prospective outcome study, 24% of ambulatory surgical patients were ASA physical status III, and these patients had the same low incidence of morbidity as ASA I and II patients.

by Warner and coworkers, JAMA, 1993

Patient Characteristics• Morbid Obesity ( BMI > 40 kg/m2 ) is no longer considered an

exclusionary criterion for day-case surgery. However morbidly obese patients with preexisting cardiovascular (e.g., hypertension, congestive heart failure, angina) or respiratory (e.g., asthma, chronic obstructive pulmonary disease) conditions had a higher incidence of perioperative morbidity than did healthy outpatients undergoing similar procedures on an ambulatory basis.

• Elderly obese patients are more likely to experience natural oxygen desaturation and episodic airway obstruction.

Patient Characteristics• OSA syndrome was not associated with increased risk of

unanticipated hospital admission.

• Smoking associated with increased risk of respiratory complications and wound infection.

• MH-susceptible patients are not appropriate criteria for admission and is eligible for ambulatory surgery provided that anesthesia and surgery was uneventful.

Patient Characteristics

Extreme of Age

• Elderly patients: Even the “elderly elderly” patient (>100 years) should not be denied ambulatory surgery solely on the basis of age, provided that: medical condition is stable, the procedure went uneventfully, family care for transportation and home care is available.

(EB: A study found that elderly patients experienced less postoperative cognitive dysfunction and disorientation after ambulatory (versus inpatient surgery). ( Kitz DS, et al, Anesthesiology 1988)

Patient Characteristics

Extreme of Age• Premature infants:

– Under GA, there is increased risk which is greatest in premature infants younger than 46 weeks’ postconceptual age of postoperative apnea. In some studies, this risk persist until the 60th postconceptual week. ( Fisher LA, et al: Anesthesiology 1995),(Malviya S, et al: Anesthesiology 1993)

– Anemia ( hematocrit < 30%) in this group of patient alone increase the risk postoperative apnea by evidence. (Welborn LG, Hannallah RS, et al: Anesthesiology 1991).

– There was no relationship between apnea and use of intraop opioid or muscle relaxant, and the use of IV caffeine may prevent apnea and desaturation in this group of patients. ( Cote CJ, et al Anesthesiology 1995),(Welborn LG, Hannallah RS, et al: Anesthesiology 1989)

Contraindication to Ambulatory Surgery

1. Potentially life-threatening chronic illnesses (e.g., brittle diabetes, unstable angina, symptomatic asthma).

2. Morbid obesity complicated by symptomatic cardiorespiratory problems (e.g., angina, asthma).

3. Multiple chronic centrally active drug therapies (e.g., use of monoamine oxidase inhibitors such as pargyline and tranylcypromine) and/or active cocaine abuse.

4. Ex-premature infants less than 60 weeks’ postconceptual age requiring general endotracheal anesthesia.

5. No responsible adult at home to care for the patient on the evening after surgery.

Anesthesia Management

• Pre-operative Assessment: - Pre-operative evaluation.- Pre-operative preparation.

• Intra-operative ( Spinal ).- Facts.- Literature Review.

• Post-operative care.

Pre-operative Evaluation

Objective : to identify patients who have concurrent medical problems requiring further diagnostic evaluation or active treatment before elective surgery in order to minimize cancellations or complications.1.History ( most valuable tool ) and Physical Examination:

- Identify the general and specific medical condition of patient, medications, and risk assessment.

- Specific anesthetic concerns: airway assessment, active cardiac or respiratory disease, previous operations and anesthesia charts if available.

- Preoperative assessment 1 to 2 weeks before surgery was found to reduce preoperative anxiety when compared with assessment on the evening before surgery.

Pre-operative Evaluation

2. Laboratory testing: - Routine preoperative laboratory testing of patients before ambulatory surgery is unjustified and extremely wasteful of valuable health care resources.- For outpatients undergoing superficial surgical procedures (e.g., biopsy, dilatation and curettage, herniorrhaphy, arthroscopy, vein stripping), no laboratory tests appear to be indicated in males, and only a hemoglobin (or hematocrit) test is indicated for adult females of child-bearing age. - Obviously patient with chronic disease require additional workup accordingly.

Pre-operative Preparation

Objective: reducing the risks inherent in ambulatory surgery, improving patient outcome, and making the surgical experience more pleasant for the patient and their family.


• Non-pharmacological:• pre-anesthesia visit alone can be more effective than

medications in relieving preoperative anxiety.• Educational programs: video instructions, books, pamphlets,

and hypnosis all seems to be beneficial.• Preoperative preparation should also include written and

verbal instructions regarding arrival time and place, fasting instructions, and information concerning the postoperative course, effects of anesthetic drugs on driving and cognitive skills immediately after surgery, and the need for a responsible adult to care for the patient during the early postdischarge period (<24 hours).


• Pharmacological:

- The use of premedication in the outpatient setting has been a subject of considerable debate over the past 30 years.

- The primary indications for preoperative medication include anxiolysis, sedation, analgesia, amnesia, and prophylaxis against postoperative emesis and aspiration pneumonia.

Pharmacologic Preparation

• Benzodiazepines:- Superior to barbiturate(residual sedation)- Prospective studies have not found recovery to be

prolonged after the use of appropriate doses of sedative premedication in the outpatient setting (midazolam 1-2mg IV).

- Midazolam has become the drug of choice because its shorter elimination half-life and its anesthetic sparing effects and lack of significant side effects facilitate the recovery process after ambulatory surgery.


• Benzodiazepines:- In addition to its well-known anxiolytic properties,

midazolam may be effective in reducing postoperative pain and nausea and improving patient satisfaction.

- Midazolam (0.5 mg/kg PO) allowed children to be separated from their parents as early as 15 minutes after oral ingestion, without prolonging recovery even after brief surgical procedures.

- In geriatric patients, premedication with midazolam (0.5-1.0 mg IV) did not adversely affect mental and psychomotor recovery, even after brief ambulatory procedures.


• α2-Adrenergic Agonists: ( Clonidine and dexmedetomidine)

- Premedication with α2-adrenergic agonist drugs produce sedation and anxiolysis while also decreasing the heart rate and blood pressure during anesthesia and opioid requirements after surgery.

Pharmacologic Preparation• α2-Adrenergic Agonists: • Clonidine: Shown to be :

- Effective in decreasing emergence delirium after sevoflurane anesthesia.

- Reduce emetic symptoms after breast surgery under GA.- Facilitate glycemic control in type-2 diabetic patients.- Reduce postoperative myocardial ischemia in patients

with preexisting cardiac disease.- When compared to oral midazolam, less effective in

reducing anxiety but produced greater anesthetic- and analgesic-sparing effects in children.


• α2-Adrenergic Agonists: • Dexmedetomidine: ( like clonidine but..)

- More highly selective α2-agonist that has a shorter duration of action than clonidine.

- Could prove valuable adjunct during surgery because of its anesthetic and analgesic sparing effects and ability to decrease postoperative pain.


• Nausea and Vomiting Prevention:- Very common postoperative complication and contribute

to patients’ dissatisfaction and delayed discharge.- The cost-effective combination of droperidol,

dexamethasone, and ondansetron is increasingly being used for antiemetic prophylaxis of outpatients undergoing a wide variety of surgical procedures.

- Antihistamines (e.g. Dimenhydrinate, hydroxyzine) used effectively to prevent PONV specially in middle ear or strabismus surgery. In combination with droperidol can reduce vomiting up to 24 hours without delaying discharge.

Intra-operative Management• Monitored Anesthesia Care.• Local Infiltration Techniques.• Regional Anesthesia:

- Peripheral Nerve Block.- IV regional anesthesia.- Epidural.- Spinal.

• General Anesthesia.

Spinal Anesthesia• Bier's breakthrough in spinal

anaesthesia was made in 1898 when he performed the first planned spinal anaesthetic on a series of 6 patients for lower extremity surgery. Each of them received a spinal dose of cocaine and did well except for having nausea, vomiting and headache afterwards.

August Karl Gustav Bier (24 November 1861, Bad Arolsen – 12 March 1949) was German surgeon and the pioneer of spinal anaesthesia.


Facts :• Probably considered the simplest and most reliable regional

anesthetic technique, but …..• Unfortunately, the incidence of side effects is surprisingly high.• Needs longer recovery time.• Most troublesome complication is the residual effect of the

block on motor, sensory, and sympathetic nervous system function ( delayed ambulation, impaired balance, dizziness, and urinary retention ).


Facts :• Although the incidence of post–dural puncture headache can

be minimized with the use of small-bore, 25-gauge pencil-point needles, the incidence of failed blocks appears to be higher.

• The goal is to apply the most appropriate technique and to select the most appropriate anesthetic-adjuvant combination to avoid prolonged undesirable effects and thus, delayed discharge.


What to use:• Local Anesthetics used for spinal like: Lidocaine, tetracaine,

Bupivacaine, Levobupivacaine, Ropivacaine, Prilocaine.

• Adjuncts i.e.: Vasoconstrictors (Epinephrine, phenylphrine), Opioids (fentanyl, sufentanyl, morphine), α-adrenergic agonists (clonidine).

Table 51-2 -- Drug Selection for Hyperbaric Spinal Anesthesia

Local Anesthetic Mixture Dose (mg) * Duration (min)

To T10 To T4 Plain Epinephrine, 0.2 mg

Lidocaine (5% in 7.5% dextrose) 50-60 75-100 60 75-100

Tetracaine (0.5% in 5% dextrose) 6-8 10-16 70-90 100-150

Bupivacaine (0.75% in 8.5% dextrose) 8-10 12-20 90-120 100-150

Ropivacaine (0.5% in dextrose) 12-18 18-25 80-110 —

Levobupivacaine 8-10 12-20 90-120 100-150

* Doses are for use in a 70-kg adult male of average height.


Facts :• Prolonging subarachnoid-induced analgesia with fentanyl

rather than epinephrine avoids the prolonged time to micturition and reduces the time to discharge from the hospital. However, the adjunctive use of the opioid increases the incidence of pruritus and PONV.

• Mini-doses of lidocaine (10-30 mg), bupivacaine (3.5-7 mg), or ropivacaine (5-10 mg) techniques combined with a potent opioid analgesic (e.g., fentanyl, 10-25 µg, or sufentanil, 5-10 µg) results in faster recovery of sensory and motor function.


Facts: • The mini-dose spinal technique involving lidocaine (10- 30

mg) and fentanyl (10-25 µg) for outpatient laparoscopic gynecologic surgery has been reported to offer significant advantages over both conventional spinal and general anesthetic techniques with respect to hemodynamic stability and speed of recovery.

• Short-acting local anesthetics (e.g., lidocaine and procaine) are clearly preferable to bupivacaine, ropivacaine, and tetracaine in achieving a rapid recovery.


Facts:• The use of lidocaine is controversial because of numerous

reports of transient neuropathic symptoms (i.e., radicular nerve root pain).

• Intrathecal bupivacaine and ropivacaine should be reserved for ambulatory procedures with an anticipated duration of more than 2 hours because of their more prolonged recovery times.

• Compared with bupivacaine, the duration of sensory blockade with ropivacaine was two thirds and the duration of motor block was half.

• Hyperbaric ropivacaine also produces a faster onset of analgesia compared with isobaric ropivacaine.

Literature Review Abstracts

A comparison of spinal anesthesia with small-dose lidocaine and general anesthesia with fentanyl and propofol for ambulatory prostate biopsy procedures in elderly patients. (Namiki A et al, 2006).

Design: prospective, randomized blind study.

Patients: 80 patients, ASA 1-2, aged 60-80 years.

Intervention: group L: (40 patients received 10mg spinal hyperbaric Lidocaine), group F/P: (40 patients received 1 mcg/kg fent. and 1mg/kg propofol induction and 90mcg/kg/hr propofol maintenance)

Results: both groups provided acceptable operating conditions for surgeons – higher incidence of hypotension in F/P group – shorter time for discharge in group F/P – no major postop side effects and high rate of satisfaction in both groups – Significantly lower total costs in L group.

A randomised study of lidocaine and prilocaine for spinal anaesthesia (G.

Ostgaard, et al 2001)• Background: Transient neurologic symptoms (TNS) are common after

lidocaine-induced spinal anaesthesia (SA). Recent data indicate that TNS may be less frequent after prilocaine-induced spinal anaesthesia, for which reason the isobaric solution was compared with lidocaine.

Prilocaine is an amide local anesthetic with similar pharmacologic properties to lidocaine and equipotent to it within a range of 40-70 mg.

• Methods: 99 patients randomised to receive 80mg isobaric prilocaine or lidocaine, both concentration 20mg/ml.

• Results: TNS occurred in 7/49 patients in the lidocaine group and in 2/50 in the prilocaine group (ns).

• conclusions: TNS also occurred with isobaric prilocaine SA - The frequency was not significantly different from that following lidocaine SA but larger studies are needed to establish the relative risk of TNS following SA induced by the two local anaesthetics - . Isobaric prilocaine has a longer duration of action than an equal dose of lidocaine and may be an alternative drug for spinal anaesthesia of intermediate or short duration.

A Prospective Comparison of Spinal Anesthesia with Hyperbaric

Bupivacaine and Hyperbaric Prilocaine. (Serrati J et al, 2010)

• Design: double blind controlled clinical trial.

• Methods: 119 patients randomized to receive 5 mg hyperbaric bupivacaine 0.5% (HB group, 58 patients) and 30 mg of hyperbaric prilocaine (HP group, 61 patients). ( arthroscopy or inguinal hernioplasty)

• Results: - no difference in onset time and motor block at incision time. - at 60 minutes post anesthesia HP group had partial motor blocking while HB group remained under complete block. - from block time to filling discharge criteria in PACU: HP average time 92 minutes and HB 103 minutes. - Length of stay in PACU : HP 40 minutes, HB 52 minutes. - Fast-track (bypass phase 1 recovery) accomplished in 11 patients on HP and 6 patients of HB.

A Prospective Comparison of Spinal Anesthesia with Hyperbaric

Bupivacaine and Hyperbaric Prilocaine. (Serrati J et al, 2010

• Conclusion: - HP group sent home 25 minutes earlier than HB group .

- HP 1% is suitable agent for lower body surgical procedures lasting less than 60 minutes.- There was no incidence of TNS in both groups. - HP could be an alternative to lidocaine for ambulatory anesthesia.

A prospective, double-blinded, randomized, clinical trial comparing the efficacy of 40 mg and 60 mg hyperbaric 2% prilocaine versus

60 mg plain 2% prilocaine for intrathecal anesthesia in ambulatory surgery. (Camponovo C

et al - Anesth Analg – 2010)• Methods:

- 90 patients receive one of the three spinal agents for less than 60 minutes procedure.• Results and conclusion:

- No major adverse reactions or transient neurological symptoms were observed in the study.

- Onset and sensory level of block was comparable in all 3 agents. - The hyperbaric solution showed faster times to motor block onset

and shorter duration of surgical block, suggesting its superiority for the ambulatory setting.

Urinary retention after spinal anaesthesia with hyperbaric prilocaine 2% in an ambulatory setting. (Kreutziger J - Br

J Anaesth - 2010)• Background: This prospective study was carried out to evaluate the

time to spontaneous micturition, quantify the rate of necessary bladder catheterizations, and identify the risk factors for urinary retention after intrathecal prilocaine administration.

• Methods: ASA I/II patients (16-80 yr) undergoing ambulatory lower limb surgery were enrolled and received spinal anaesthesia using hyperbaric prilocaine 2% (60 mg). Ringer's lactate was administered for peroperative volume replacement. Bladder ultrasound was performed hourly until spontaneous micturition or catheterization, when bladder filling reached 600 ml, and they were unable to urinate spontaneously.

• Results: 86 patients completed the study (49 males and 37 females). 37.8% of the women and 12.2% of the men required catheterization. Mean time between spinal anesthesia and catheterization was 190 min, and 260 min to micturition. Age <40 or >60 yr and female gender were predisposing factors for urinary retention.

Urinary retention after spinal anaesthesia with hyperbaric prilocaine 2% in an ambulatory setting. (Kreutziger J - Br

J Anaesth - 2010)• Conclusion:

- After spinal anaesthesia with hyperbaric prilocaine 2% (60 mg) for ambulatory lower limb surgery, 23% of patients required postoperative urinary catheterization.

- Postoperative bladder ultrasound and early catheterization are essential to avoid bladder distension and facilitate discharge in patients after intrathecal prilocaine 2% administration in ambulatory surgery.

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spinal anesthesia for ambulatory surgery

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