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 ::  Abstract
 ::  Introduction
 ::  Case report
 ::  Discussion
 ::  References

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Year : 1996  |  Volume : 42  |  Issue : 4  |  Page : 127-8

Anaesthetic management of a morbidly obese patient.

Department of Anaesthesia, K E M Hospital, Parel, Mumbai.

Correspondence Address:
L V Tuteja
Department of Anaesthesia, K E M Hospital, Parel, Mumbai.

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Source of Support: None, Conflict of Interest: None

PMID: 0009715317

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 :: Abstract 

Morbid Obesity (MO) is associated with various pathophysiological changes which affect the outcome of anaesthesia and surgery. We report here anaesthetic management of a fit morbidly obese patient for transcervical resection of endometrium (TCRE) under spinal subarachnoid block. The preoperative preparation, intraoperative and postoperative management is described and the various problems in morbidly obese patients are discussed.

Keywords: Anesthesia, Spinal, methods,Case Report, Female, Human, Middle Age, Obesity, Morbid, complications,Perioperative Care, Preoperative Care, Uterine Hemorrhage, complications,surgery,

How to cite this article:
Tuteja L V, Vanarase M Y, Deval D B. Anaesthetic management of a morbidly obese patient. J Postgrad Med 1996;42:127

How to cite this URL:
Tuteja L V, Vanarase M Y, Deval D B. Anaesthetic management of a morbidly obese patient. J Postgrad Med [serial online] 1996 [cited 2023 Sep 23];42:127. Available from:

  ::   Introduction Top

Morbid obesity is defined by weight alone. {Over 100 Lbs above Ideal Body Weight (IBW) or twice IBW or by BMI (Body mass index) > 35 or truncal obesity with waist 1 hip ratio > 0.9 in women}. Pickwickian Syndrome was named by Bur-well in 1956. The syndrome consists of MO, somnolence, alveolar hypoventilation, periodic respiration, hypoxemia, secondary polycythemia, right heart failure and right ventricular hypertrophy.

It is not common to encounter morbidly obese patient in India.

  ::   Case report Top

A 45-year-old, 130 kg weight, 152 cm tall female patient was taken up for TCRE for dysfunctional uterine bleeding. The patient had no significant past medical history and had undergone tubal ligation and dilation and curettage a few years ago (in non-obese state) under genera) anaesthesia with uneventful recovery. Patient gradually put on weight over two years. It was dietary in origin and endocrine causes like Cushings syndrome, hypothyroidism, hypogonadism, hypothalamic dysfunction were ruled out. The IBM of the patient was 47 kgs and BMI was 58. Patient had normal mouth opening and neck movements; cardiovascular and respiratory systems were normal on clinical examination. The routine haematological investigations, biochemistry, liver function tests, thyroid function tests and lipid profile were normal. ECG and X-ray chest were normal. X-ray neck AP, Lateral and indirect laryngoscopy did not reveal evidence of difficult airway intubation. ABG, PFT, oxygen consumption were done to assess the extent of cardiopulmonary derangement. 2D Echo and ABG were, within normal limits and PFT showed moderate restrictive pulmonary function.

The patient was morally prepared and informed valid consent was taken for hysterectomy as TCRE could proceed to hysterectomy. On the previous day the patient was taken to the operation theatre to combat the technical difficulties like size of the table. BP cuff, intravenous line access and lithotomy position. Spine was examined and L4-5 space was palpated.

Patient was given 20 mg. Omeprazol 8 hours before surgery. Anaesthesia trolley was prepared in view of regional, general anaesthesia, difficult intubation and resuscitation. Drug doses were calculated and loaded; isoflurane was kept ready, smaller endotracheal tubes, stylet and large blade laryngoscope were kept ready.

Patient was given subarachnoid block with no. 22 disposable spinal needle in sitting position at L4-5 space with 3.5 cc. of 0.5% Bupivacaine heavy it took some time to position the patient supine. Vital parameters were monitored clinically Blood pressure was monitored using a large sized cuff with mercury sphygmomanometer on one arm and automatic sphygmomanometer on the other. Cardioscope Ah the defibrillator, pulse oximeter and capnometer by face mask were used to monitor cardiovascular function.

Within 5 minutes, the sensory level reached T4 simultaneously BP decreased to 70 mm of Hg and pulse to 56/min but SaO2 was normal and patient was comfortable and had normal breathing. Intravenous fluids (rapid) and Inj. atropine 0.6 mg IV was given. Head high was given, as the drug was not fixed yet. O2 with FiO2 0.4 was started. All these maneuvers helped in restoring pulse and B P to 70/min and 1441 84 mm of Hg respectively within the next 15 minutes. Surgery was done in lithotomy position, which lasted for 1 and 112 hrs. Patient was given 500 ml 5% dextrose arid 250 ml of Ringer Lactate and had 150 ml blood loss. Patient was monitored continuously, the records were maintained every 5 min. No sedative or anxiolytic was given, as the patient was comfortable arid relaxed.

Postoperatively, the patient was given supine position with FiO2, 0.4 Vital parameters were recorded, patient was observed for respiratory obstruction and pain. Effect of subarachnoid block wore off at the end of 4 hours. Early mobilisation was achieved from the evening of 2nd day of surgery.

  ::   Discussion Top

The various pathophysiological changes in MO should be taken into consideration for planning anaestheso. The respiratory changes in these patients are decreased FRC, increased CC to FRC increased ventilation perfusion mismatch and later pulmonary hypertension. Therefore, hypoxia and hypercarbia should be avoided [1]. The patient on controlled ventilation should be ventilated at low rate, more tidal volume and adequate expiratory pause. MO requires high FiO2 to achieve adequate oxygenation and therefore the ratio of nitrous oxide and oxygen should be kept at 3:2. Patient should be supplemented with oxygen in case of regional anaesthesia. Head low and head low with lithotomy might have precipitated hypoxia and hypercarbia in our patient, therefore head low was avoided in the intra as well as postoperative period in our patient, abdominal procedure was avoided to avoid postoperative pulmonary complications.

The changes that are expected in the cardiovascular system are: increased blood volume, cardiac output. ventricular work load, increased oxygen consumption arid CO, production, systemic and pulmonary hypertension and later biventricular failure [2]. The MO are more prone to arrhythmias due to ischemic heart disease, electrolyte imbalance, drugs and sleep apnoea. The cardiovascular responses to various stimuli are of extremes. Thus, they should be fully investigated and monitored. In our patient, pulmonary artery pressure was not done, as ABG, 2D Echo and PFT did not indicate its need.

The other challenges in these patients are of maintaining airway, intubation difficulties, associated diabetes mellitus and acid aspiration. In our patient, we used proton pump inhibitor omeprazol to prevent acid aspiration. Awake or spontaneous intubation may be required and the patient should not be paralysed when difficulty is anticipated.

The changes in pharmacokinetics and dynamics of the drugs in MO are due to decreased total body water, increased fat, increased lean body mass, blood volume cardiac output plasma triglycerides and cholesterol and absolute body water. Thus lipophilic drugs require larger inducing doses and have large, volumes of distribution and prolonged elimination Therefore, thiopentone and propofol are required in higher inducing doses (7 and 5 mg/kg LBW resp.) and benzodiazepines are given in usual doses/kg body weight[4].

Though the blood volume and therefore the plasma cholesterol amount is increased. Succinylcho-line upto 120-140 mg is adequate in most of the MO patient. Water-soluble non depolarising muscle relaxants like pancuronium, vecuronium and atracurium are given in same doses per kg body weight but neuromuscuiar blockade should be monitored.

The MO patients metabolise halothane and enflurane to a greater extent than non obese leading to higher fluoride levels. High serum bromide levels and halothane hepatitis are more common in obese patients[2],[3],[4].

Regional anaesthesia not interfering with the cardiovascular status of the patient is preferred[4], Doses of lignocaine are calculated similar to that in the non obese. The doses of local anaesthetics should be reduced by 25% for subarachnoid and epidural blocks. If the level goes above T4 intensive cardiorespiratory monitoring should be done. Regional analgesia like epidural analgesia with light general anaesthesia may have several advantages like cardiovascular stability adequate oxygenation, reduced doses of narcotics or inhalation agents[5]. Technical difficulties may be faced during regional analgesia. Postoperative consideration should be given to hypoxia, positioning, fluid intake - output, humidification of the oxygen, chest physiotherapy and incentive spirometry, deep vein thrombosis, analgesia respiratory obstruction and wound infection, and early ambulation.

 :: References Top

1. Stolting RK. Anaesthesia and co-existing diseases. pp 541-546  Back to cited text no. 1    
2.Buckley FP. Anaesthesia for morbidly obese patient. Can J of Anaesthesia 1994/41; 5/pp R: 94-100.  Back to cited text no. 2    
3.Shenkman Z. Preoperative management of the obese patient. Br J of Anaesthesia 1993; 70:349-359.  Back to cited text no. 3    
4.Fox GS. Anaesthesia for morbidly obese Br J of Anaesthesia 1981; 53:811-816.  Back to cited text no. 4    
5.Hanrem CW. The implications of MO for anaesthesia Anaesthesiology Review. 1979; 6:29-35.   Back to cited text no. 5    


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Online since 12th February '04
2004 - Journal of Postgraduate Medicine
Official Publication of the Staff Society of the Seth GS Medical College and KEM Hospital, Mumbai, India
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